Grinding in motion by nikeborome

VIEWS: 418 PAGES: 72

									                                                                    ISSUE 1/2009




MOTION                          THE CUSTOMER MAGAZINE OF THE SCHLEIFRING GROUP




Grinding in motion
Special edition: SCHLEIFRING Grinding Symposium 2009




KNOW-HOW: SCHLEIFRING Group innovations
BEST PRACTICE: Presentations by highly respected experts
PROFILE GRINDING
WITH WINTERTHUR:
            Y
PASSIONATEL PRECISE




Switzerland                    USA                                   United Kingdom                    Germany
Winterthur Schleiftechnik AG   Winterthur Corporation                Winterthur Technology UK Ltd.     Winterthur Schleiftechnik GmbH
Oberer Deutweg 4               10 Viking Road                        2 Oakham Drive                    Hundsschleestrasse 10
8411 Winterthur                Webster MA 01570                      Parkwood Industrial Estate        72766 Reutlingen
Tel.: +41 (0)52 234 41 41      Tel.: +1 (508) 949 10 61              Sheffield S3 9QX                   Tel.: +49 (0)7121 93 24 0
Fax: +41 (0)52 232 51 01       Fax: +1 (508) 949 20 86               Tel.: +44 (0)114 275 42 11        Fax: +49 (0)7121 93 24 24
wst@rappold-winterthur.com     info@winterthurusa.net                Fax: +44 (0)114 275 41 32         info@rappold-winterthur.de
                                                                     info@winterthurtechnology.co.uk

Germany                        Austria                               Sweden
WENDT GmbH                     Rappold Winterthur Technologie GmbH   SlipNaxos AB
Fritz-Wendt-Strasse 1          St. Magdalenerstrasse 85              Folksparksv. 31
40670 Meerbusch                9500 Villach                          59383 Västervik
Tel.: +49 (0)2159 671-0        Tel.: +43 (0)42 42 41 811 0           Tel.: +46 (0)490 843 00
Fax: +49 (0)2159 806 24        Fax: +43 (0)42 42 41 811 701          Fax: +46 (0)490 146 00
info@wendtgroup.de             office@rappold-winterthur.at           support@slipnaxos.se




www.winterthurtechnology.com
                                                                                           EDITORIAL




Technologies for the future


Dear Readers,


The economic and financial crisis has the world on tenterhooks. Even key sectors,
like the automotive, aircraft and machine construction industries, are severely
affected by the changes. Lots of people are asking: When will we emerge from the
crisis and how? And what will the future bring? Yet times of economic difficulty
also present opportunities. Firms that set the right objectives now will be in a good
position after the recession. Experts are sure that with expertise and cutting-edge
technology we can face the future with optimism.


The SCHLEIFRING Group is therefore aiming for technological leadership in all areas
of fine machining. See for yourself at the SCHLEIFRING Grinding Symposium 2009.
We will be demonstrating our latest products and developments live at 17 stations,
from solutions designed to increase productivity and quality to efficient software
tools and fully developed measuring technology. The demonstra-
tions will be supported by presentations given by leading
industry experts. Their talks will provide insights into the
latest research findings.


This special edition of MOTION brings together the key
information. You can look forward to a varied mix of
scientific research and practical application. We hope
you enjoy reading this issue of MOTION.




           rely
Yours sincerely




          mmermeier
Dr Ralf Kammermeier
Managing Director
           eifring
Körber Schleifring GmbH




                                                                                        MOTION 01/09   3
CONTENTS
20                                                                                    30
TOO L S & T EC H N O LO GY

     Cylindrical grinding                          Surface grinding                             Tool grinding
12   Station 4 – STUDERmodular                08   Station 1 – MÄGERLE                     24   Station 13 – EWAG COMPACT LINE
     From heavy-duty applications to               Optimum surface quality and accuracy.        The EWAG COMPACT LINE is
     flexible production – the S22 leaves           Manufacturing printing rollers on an         designed for the flexible manufacture
     nothing to be desired                         MFP traverse table machine                   of all types of inserts


13   Station 5 – STUDERmicro                  10   Station 2 – BLOHM JUNG                  25   Station 14 – EWAG EWAMATIC LINE
     Precise, productive and reliable – the        Forward-looking surface and profile           Fully automated machining of
     manufacture of small and micro parts          grinding with modern control and             PCD/PCBN equipped highly complex
     on the S21 and S12                            machining systems                            round tools


14   Station 6 – STUDERinternal               11   Station 3 – BLOHM JUNG GEOID            26   Station 15 – WALTER
     Flexible manufacture in small batch           The efficiency of diamond wear                HELITRONIC MICRO and HELICHECK
     and large batch production                    compensation using high-perfor-              PLUS – the high-performance double
                                                   mance blanking punches                       act for micro tools
17   Station 8 – MIKROSA
     Complete machining: High-speed                Service                                 27   Station 16 – WALTER
     grinding of jet needles on the           16   Station 7 – SERVICE Quality                  Perfect cutting edges of PCD tools
     MIKROSA KRONOS S                              Systematic servicing carried out             manufactured on the HELITRONIC
                                                   by SCHLEIFRING Service optimizes             POWER DIAMOND
19   Station 9 – SCHAUDT ShaftGrind S              machine availability
     Machining of drive shafts with                                                        28   Station 17 – WALTER
     swivel-in spindle technology                                                               Tapping the full potential
                                                                                                of tool grinding machines:
20   Station 10 – SCHAUDT CamGrind L2                                                           HELITRONIC ToolStudio is
     With swivel-in spindle technology                                                          the no. 1 software
     camshafts are machined complete in
     one clamping


22   Station 11 – STUDERflexible
     The STUDER S242 with three
     cross-slides is the most flexible
     hard fine machining center


23   Station 12 – STUDERintelligent
     StuderTechnology optimizes the
     grinding processes on the S 31 and
     S33 by up to 50 per cent                      14
4     MOTION 01/09
                                                                                                                                                                    CONTENT




                            32                                                                           44
MARKETS & TRENDS

        Technical Symposium I:                                                                48      Lecture III-2 Dr Bernd Möller: New grinding spindles for
        Innovative production                                                                         operation at extremely high rotary speeds
30      Lecture I-1 Prof. Thomas Straubhaar: The global
        economy in recession: what can be done?                                               50      Lecture III-3 Harro Wörner: Global strategy of standard ma-
                                                                                                      chines from the point of view of the large volume manufacturer
32      Lecture I-2 Prof. Eckart Uhlmann: Quo vadis
        precision machining?                                                                  52      Lecture III-4 Udo Mertens: High performance grinding
                                                                                                      wheels for external cylindrical grinding
34      Lecture I-3 Dr Hans-Werner Hoffmeister:
        Effective cooling and lubricating in grinding                                                 Technical Symposium IV: Tool grinding
                                                                                              54      Lecture IV-1 Prof. Wilfried Saxler: Tool grinding –
36      Lecture I-4 Johann Noichl: Dressing grinding                                                  the industry of the future
        wheels – a nice piece of work?
                                                                                              56      Lecture IV-2 Dr Dieter Kress: Multi-axis precision grinding
        Technical Symposium II:
        Surface and profile grinding                                                           58      Lecture IV-3 Christoph Hübert: New methods for
38      Lecture II-1 Prof. Taghi Tawakoli: Advantages of ultrasonic                                   the manufacture and use of micro cutting tools
        grinding and dressing compared to conventional grinding
        and dressing                                                                          60      Lecture IV-4 Oliver Wenke: Measuring technology
                                                                                                      guarantees cost-effective tool production
40      Lecture II-2 Prof. Wilhelm Schröder: Professionally
        compensating for form deviations during profile dressing                                       Technical Symposium V:
                                                                                                      Universal cylindrical grinding
42      Lecture II-3 Dr Christoph Zeppenfeld: Interactions of process                         62      Lecture V-1 Prof. Konrad Wegener: Simulation of abrasive
        and machine when surface grinding                                                             tools and processes


44      Lecture II-4 Dr August Kästner: Efficient grinding of                                  64      Lecture V-2 Dr Frank Fiebelkorn: Efficient hard fine machining
        components for vane pumps and motors
                                                                                              66      Lecture V-3 Dr Carsten Russner: Precision grinding of brittle
        Technical Symposium III:                                                                      hard ceramics under production conditions
        Production cylindrical grinding
46      Lecture III-1 Prof. Klaus Weinert: Innovative concepts for                            69      Lecture V-4 Walter Graf: How do you choose the ‘ideal’
        internal cylindrical machining                                                                abrasive material?




IMPRINT
Publisher: Körber Schleifring GmbH, Hamburg Chief editor: Peter Lütjens Realization: JDB MEDIA GmbH, Schanzenstraße 70, 20357 Hamburg, Germany Project management:
Jan Hawerkamp Art direction: Claudia Schiersch Editorial board: Marc-Oliver Prier (dir.), Dania Müller, Ira Schroers Layout: Steffi Pfl ugbeil (Ltg.), Yvonne Vahland Proofreading, editing
and translation: SKH SprachKontor Hamburg GmbH Photos: ddp-archiv (2), F1 online (1), Getty Images (2), PR/Hersteller (142) Lithography: Fire Dept. GmbH, Hamburg Printing: NEEF +
STUMME GmbH & Co. KG, Wittingen



                                                                                                                                                            MOTION 01/09               5
MOTIONS & MORE




SCHLEIFRING GRINDING SY MPOSIUM 20 0 9


Grinding in motion

At the heart of things, between
the machine presentations and
the lectures, experts in the
mechanical engineering sector
can meet in front of the bar to
exchange news and views




SCHLEIFRING is showing its comprehensive services from May 6 to 8, 2009. The SCHLEIFRING
Grinding Symposium will be rounded off with lectures by well-known experts in the grinding sector.




T    he SCHLEIFRING Grinding Sympo-
     sium 2009 is fully geared to for-
ward-looking development, effi cient
production and successful sales.              Technical symposium I, May 6, 2009, 14.00 to 17.00: The speakers on the
                                              subject of Innovative Production are Prof. Thomas Straubhaar, Prof. Eckart
    A varied program                          Uhlmann, Dr Hans-Werner Hoffmeister and Johann Noichl
The eight SCHLEIFRING companies will          Technical symposium II, May 7, 2009, 9.30 to 11.30: Prof. Taghi Tawakoli,
be present on 17 stands in all where          Prof. Wilhelm Schröder, Dr Christoph Zeppenfeld and Dr August Kästner are
visitors can have first-hand experience        our speakers on surface grinding and profile grinding
of the latest products and technical          Technical symposium III, May 7, 2009, 14.00 to 17.00: The subject of produc-
developments. In addition, there will be      tion grinding and cylindrical grinding will be dealt with by Prof. Klaus
presentations that clarify technological      Weinert, Dr Bernd Möller, Harro Wörner and Udo Mertens
improvements in productivity and qual-        Technical symposium IV, May 8, 2009, 9.30 to 11.30: Prof. Wilfried Saxler,
ity in finish machining and effi cient          Dr Dieter Kress, Christoph Hübert and Oliver Wenke are our experts on tool
software solutions. The machine pre-          grinding
sentations will be given in German,           Technical symposium V, May 8, 2009, 14.00 to 17.00: Visitors will hear all
English, French and Italian (see right-       about universal cylindrical grinding from Prof. Wegener, Dr Frank Fiebel-
hand column for details). In addition to      korn, Dr Carsten Russner and Walter Graf
these practical machine presentations
there is also a theoretical program of       A relaxing end to the day
fi ve colloquia with a total of 20 talks    After the machine presentations and lectures the evenings will finish with a pro-
given by well-known experts in the field    gram including musical highlights and exceptional performances in the Kursaal
to round off the three days of the sym-    Casino at Interlaken. This also gives all delegates another opportunity for network-
posium.                                    ing and exchanging ideas with colleagues.




6        MOTION 01/09
                                                            INFO
                                                                           ENTRANCE




                                                                                                                                     Overview: Using this plan (above) you can easily
                                                                                                                                     find your way to the various stands. The table
                                                                                                                                     below shows when each machine presentation
                                                                                                                                     will be given in which language




                                 SCHLEIFRING GRINDING SYMPOSIUM 2009 – SCHEDULE OF EVENTS
Station      Subject                                   9.30        10.00              10.30   11.00   11.30    12.00           14.00     14.30    15.00     15.30    16.00     16.30
             MÄGERLE: Optimum surface
1            quality and accuracy
                                                        D            F                 D        I       E                       D          F         D         I        D        E

             BLOHM JUNG Forward-looking surface
2            and profi le grinding
                                                        E           D                   F      D        I                       E          D         F        D         I        D

             BLOHM JUNG: GEOID diamond-wear
3            compensation
                                                        I            E                 D        F       D                      Press       E         D        F         D         I

4            STUDERmodular                              D            I                 E       D        F                        I         D         E        D         F        D

5            STUDERmicro                                F           D                   I      E        D                       D           I        D        E         D        F

6            STUDERinternal                             D            F                 D        I       E                        F       Press       I        D         E        D

7            SERVICE Quality                            E           D                   F      D        I                       D          F         D         I        D        E

             MIKROSA: High-speed grinding
8                                                       I            E                 D        F       D                       E          D         F        D         I        D
                                                                                                                 Lunch break




             of jet needles
             SCHAUDT: Machining of drive shafts
9            with swivel-in spindle technology
                                                        D            I                 E       D        F                       D          E      Press       F         D         I

             SCHAUDT: Complete machining of
10           camshafts
                                                        F           D                   I      E        D                        I         D         E        D         F        D

11           STUDERflexible                              D            F                 D        I       E                       D           I        D        E         D        F

12           STUDERintelligent                          E           D                   F      D        I                        F         D         I        D         E        D

13           EWAG: Flexible manufacturing of inserts    I            E                 D        F       D                       D          F         D         I     Press       E

14           EWAG: Machining of PCD tools               D            I                 E       D        F                       E          D         F        D         D         I

             WALTER: High-performance double act
15           for micro tools
                                                        F           D                   I      E        D                       D          E         D        F         I        D

             WALTER: PCD tools – perfect
16           cutting edge
                                                        D            F                 D        I       E                        I         D         E        D         F        D

17           WALTER: HELITRONIC ToolStudio              E           D                   F      D        I                       D           I        D      Press       E        F

    German           English            French                 Italian                          Press, May 6, 2009 only, otherwise in German




                                                                                                                                                           MOTION 01/09                 7
TOOLS & TECHNOLOGY




Optimum sur face qualit y


A strong worker
The MÄGERLE hydrostatic guidance systems set standards in the matter of precision when
machining larger components.




E   xperts in evolving solutions ex-
    actly tailored to the customer’s
needs – this is the specialty of the
SCHLEIFRING company MÄGERLE. In            piece in the machine, and together with the processing forces calculates ap-
particular when handling large com-        propriate corrections. In the grinding process which follows, the machine then
ponents, the hydrostatic guidance sys-     travels fully automatically precisely in accordance with the values given. The
tems of the MÄGERLE machine ranges
make the highest levels of precision
possible.


    Automatic compensation
At the SCHLEIFRING Grinding Sympo-
sium 2009 the Swiss company is show-
ing the ma-chining of large compo-
nents using a plate cylinder for the
printing industry as an example. The
task of grinding is precise machining
of the start and end of print line which
is longitudinally arranged on the
chrome-plated plate cylinder. High
standards are set here both for accu-
racy and for quality of the surface fi n-
ish. In components of this size and
weight (the cylinder measures 500 mil-
limeters in diameter, is 1,600 millime-
ters long and weighs 1,000 kg), special
strategies are necessary for machining.
Due to its weight and also the forces
on the machining, the workpiece bends
and becomes misshapen. Where high
levels of accuracy are demanded, there
must be precise compensation for
these sources of error.
For this purpose MÄGERLE has devel-
oped a compensation algorithm which
measures the deflection of the work-       Speaks for itself: Edges of the printing roller are ground absolutely precisely on the MFP-220




8      MOTION 01/09
                                                                  STAND



The combination professional:
The MÄGERLE MGC-L-330
with fully automatic tool changer




hydrostatic guidance concept makes it possible to move heavy work-
pieces almost without friction, which makes a decisive contribution to the
quality of the surface finish. The combination of machine concept with
hydrostatic guidance, integral measurement and fully automatic compen-
sation guarantees the customer an optimum result, even for the heaviest
components.                                                                  We optimize your
                                                                             grinding process
   Complex combined machining
However, modern MÄGERLE grinding centers don’t only solve pure grin-
ding tasks in a reliable manner. They also handle complex combination
machining with geometrically-defined cutting edge such as hard turning,
hard milling or drill-ing too. Machining the workpieces in a single clamp-
ing also has decisive influence on productivity and on quality of the com-
ponent. An ex-ample of such a combination machine is the MÄGERLE
MGC-L-330. The grinding center comprises a fully-automatic tool-chang-       Meet us
ing sys-tem, a horizontal grinding spindle and a table dressing device.
                                                                             Schleifring Grinding Symposium
Machining with geometrically defined cutting edges is carried out with
an additional vertical direct drive spindle, which can be swiveled through
                                                                                           2009
90°. Due to the extreme rigidity of the large-area hydrostatic guides, im-
pressive cutting values can be                                                         6.– 8. Mai
achieved. The result speaks for itself:       FURTHER INFORMATION                      Thun/Schweiz
reduced machining time and the            +++ sales@maegerle.com
greatest possible accuracy.               + + + w w w.maegerle.com + + +
                                                                             Dittel Messtechnik GmbH
                                                                             Tel.: +49 (0)8191 3351-0
                                                                             www.dittel.com
TOOLS & TECHNOLOGY




                                                                                                                                                STAND



For ward-looking sur face and profile grinding


The next generation
Fast and outstandingly user-friendly – these are the convincing advantages of the modern
con-trol and machining systems by BLOHM JUNG.




W       ith the CNC-Light Control, BLOHM
        JUNG introduces a new genera-
tion of controls. It can interpolate up to
                                                                     5-SIDED-GRINDING ON THE PROKOS
                                                               Workpiece: Length × breadth × height = 100 × 70 × 40 mm – 3 grinding wheels
four axes at the same time and traverse                            Operation stages 1 + 2
them towards each other. The technology                            Wheel No. 1 – traverse plunge – grinding wheel
is thus perfectly suited for high-end ma-                          set angle (A-axis) = 70°

chines with a limited number of axes. The                          Operation stages 3 + 4
special feature of the CNC-Light Control:                          Wheel No. 1 – traverse plunge –
both the FANUC control operator panel                              set angle 25°
and the functional scope of the machining                          Operation stage 5
possibilities (cycles) were a complete in-                         Wheel No. 2 – traverse plunge –
house development by BLOHM JUNG.                                   set angle 45°
A new feature is the method of working                             Operation stage 6
with the workstation editor, which is ori-                         Wheel 2 – profile traverse grinding with
ented towards the STUDER pictogram-                                three interpolating axes – set angle 45°
ming (see Station 5). Broadly in line with
                                                                   Operation stage 7
the motto ‘more pictures – less words’,                            Wheel 3 – flat grinding with continuous
BLOHM JUNG introduces the user-                                    traverse – set angle 20°
friendly working method of the new con-
trol on a PROFIMAT at Station 2.
                                                outstanding performance and process reliability are thoroughly convincing. As
     Breathtaking speed                         a basic machine equipped with three axes, it can be upgraded to a five-axis ma-
Also at Station 2: the latest news in           chine with a high-speed rotary table and a swiveling grinding spindle drive. It
speed-stroke technology, as exempli-            can grind different profiles in a single clamping – with concave or convex radii,
fied by the PROKOS, which grinds fi ve            as desired, and it can also be used for drilling, milling or grinding. Speed-stroke
sides of a workpiece in seven grinding          grinding is known for its fast traverse speeds and acceleration and a fast machin-
operations (see table). Its features of         ing process and very short cycle times. On account of the fast feed rate – 80 to
                                                120 m/min at infeed rates of up to 0.01 millimeters per traverse stroke – a large
                                                proportion of the process heat is carried away by the chips. The edges of the
                                                workpiece remain undamaged even where the cooling and grinding conditions
                                                are less than optimum. A well thought-out procedure for the process rounds off
                                                the profile of the PROKOS. The selection of parameters is simpler, the coolant
                                                feed is less critical and the performance limit can easily be determined from the
                                                wear on the grinding wheels.
                                                                                                                FURTHER INFORMATION

                                             Right at the top: The speed-stroke technology of
                                                                                                         + + + p e t e r. o p p e l t @ b l o h m j u n g . d e
                                             the PROKOS means very short cycle times                     + + + w w w.blohmjung.de + + +




10      MOTION 01/09
                                                                                                                                          STAND



G EO I D d i a m o n d - w e a r c o m p e n s a t i o n


It all depends on the contour
GEOID wear compensation
eliminates faults on dressing
tools accurate to the last μ.




G     rinding wheel profiles cannot be
      exactly dressed without the use of
a geometrically-perfect dressing tool.
Even new diamonds are not always per-
fect. At the SCHLEIFRING Grinding Sym-
posium 2009, BLOHM JUNG pre-sents
for the first time ever under the expres-
sion GEOID a new development for                             Swiveling: GEOID in combination with
compensa-tion of contour faults in dress-                    flexible dressing systems guarantee perfect
                                                             contours on the grinding wheel [1 + 2]
ing tools. The example shows the quick
manufacture of a blanking punch on the                                                                                        [1]
VARIO D. GEOID was developed in con-
cert with the Georg Simon Ohm Univer-                        Ready for use in six minutes
sity in Nuremberg. The software for                        For profile grinding, different dressing systems are
com-pensation of uneven wear in dress-                     available for the VARIO range of profile grinders by
ing tools is a further development of the                  BLOHM JUNG. According to requirements, profiled
automatic diamond adjustment by                            crushing units, fixed profile diamonds or swiveling
BLOHM JUNG and is used in conjunction                      diamond wheels are mounted on the grinding table.
with the CNC PA37K profile dressing de-                     Highlight is the CNC PA37K head dressing unit. The
vice and the table version PA130TM.                        possibility of using both individual diamonds and
Topography of the cutting edge of the                      driven diamond wheels for profiling is unique in the
                                                                                                                              [2]
dressing tool can be determined with                       world. Even when preparing the diamond tools the
μ-accuracy using GEOID. The correction                     automatic diamond adjustment saves a lot of time. A diamond star with six dia-
values calculated are fed directly into                    monds is ready for use in only six minutes, a diamond wheel in ten. The function
the dressing program and create a per-                     ‘CD Abrichten’ (continuous dressing), or parallel dressing, cuts machining times
fect contour on the grinding wheel. Re-                    by up to 50 per cent.
sult: an increased service life for the
dressing tool, reduced costs of tools and                    Determine, analyze, compensate
the contour accuracy is improved.                          But even the best dressing tools wear, and this has an influence on dressing con-
                                                           tours. BLOHM JUNG shows at Station 3 how the GEOID correction software
                                                           determines the actual contour of the diamond via a measuring probe and then cor-
                                                           rects the dressing program accordingly. Thus GEOID compensates for the wear in
                                                           individual diamonds and diamond
Best contour
accuracy:                                                  wheels, in-creases the usability of the             FURTHER INFORMATION
Produce perfect
                                                           dressing tools by a multiple and re-            +++ achim.bauder@blohmjung.com
workpieces with
GEOID                                                      duces the costs of tools considerably.          + + + w w w.blohmjung.c om + + +




                                                                                                                                MOTION 01/09   11
TOOLS & TECHNOLOGY




                                                                                                                                                   STAND



STUDERmodular


Your personalized S22
The customer’s workpiece is the focal point. The customer chooses what he really needs,
just like a construction kit. No more and no less. The choice leaves nothing to be desired.




T     he new production platform can be
      configured for almost every grin-
ding task. Effi cient production grinding,
high-speed grinding or heavy-duty
applications – the S22 has a construc-
tion set at its disposal filled with every
component STUDER has ever devel-
oped and produced for CNC production
machines. From workpiece spindle
heads with chuck or universal design,
to standard or high-precision C-axes
with different power settings of belt or
motor spindle head, to tailstocks for
standard, synchronous or fine grinding
applications. Various dressing options
and accessories such as measuring
                                            Modular design: Production grinding and dressing (top right), heavy-duty plunge grinding (be-low right),
control and clamping devices complete       high-speed grinding with two grinding wheels (below) or non-circular grinding (below left) – the S22 can be
the range of services. In short, indi-      configured flexibly and individually to customer requirements

vidually equipped to customer require-
ments, the S22 is the perfect machine
– for heavy-duty applications as well
as fl exible production.                        High-speed grinding (HSG) with cutting speeds of 80 to 140 m/s or heavy-
                                               duty applications for grinding wheels of 610 mm diameter and 160 mm width.
     Sophisticated software                    The S22 is compatible with various loading and unloading systems and can
Sophisticated software completes               be loaded from both sides and from above. The platform is suitable for linking
the mechanical concept of the S22.             several machines together
StuderWIN operator interface and               Two different axis drive systems are available. The X-axis has antifriction
StuderGRIND software modules guar-             guideways as standard and the Z-axis has guideways with a patented surface
antee the effi ciency of the machine.           structure. Both axes have ball screw linear drives
Integral measuring system, handling            Direct drive and non-contact guideways are optional for both axes. The
system, sen-sor technology for process         combination of hydrostatic guides and linear motors permits axis movements
monitoring and automatic balancing             of up to 30 m/min. Precision to a tenth of a micrometer is easily achieved,
systems ensure standardized program-           thanks to the measuring system resolution of 0.01 μm
ming of the different systems. These
and the following performance fea-          The platform concept can be experi-                             FURTHER INFORMATION
tures make the STUDER S22 a real all-       enced close up at the Grinding Sym-                      + + + m i c h e l e .f a h r n i @ s t u d e r. c o m
rounder:                                    posium.                                                  + + + w w w. s t u d e r. c o m + + +




12      MOTION 01/09
                                                                                                                                          STAND



S T U D E R m i c ro


You can’t get more accurate than this
STUDER shows the machining of small precision parts for individual and production operations
with accuracies of up to a tenth of a micrometer.




M      anufacturers of small and micro
       parts have known the secret for
some time: STUDER cylindrical grinding
machines impress with precision, pro-               an automatic swivel function. A tiltable dressing
ductivity and reliability. If all-purpose           unit ensures perfect dressing conditions for internal
and highly effi cient machining of small             grinding without compromising geometries.
parts is required, then the S21 universal           Using three grinding wheels brings distinct advan-
cylindrical grinder or the S12 cylindrical          tages. Machining the workpiece in one set-up guar-
production grinder is for you.                      antees optimum concentricity and at the same time
                                                    eliminates downtime for re-clamping. Special
   Pressure piece with external                     STUDER grinding software helps to utilize the ma-
                                                                                                                               Angular infeed grinding
   thread on the S21                                chine’s full potential. ‘Pictogramming’ software
The largest external diameter of the                supports the operator when creating effi cient grin-
30-millimeter-long component is 18                  ding and dressing programs. STUDER Quick-Set ®
millimeters; the internal diameter is 7             set-up software facilitates workpiece set-up and
millimeters. The S21 grinds workpieces              changeover. StuderThread software helps when
in one set-up and can be equipped with              programming the dressing program for thread
two external grinding wheels and one                grinding. Following the completion of this machin-                                 Thread grinding
high-frequency spindle for internal                 ing process, the workpiece is ready for the next
grinding. The B-axis is equipped with               process steps.


                                                      Bearing inner ring on the S12
High-tech machine: The S12 with linear motors and   The high-tech S21 excels at machining a bearing
hydrostatic guideways
                                                    inner ring. A combination of linear drives and hy-                                Internal grinding
                                                        drostatic guideways gives excellent results
                                                                                                                 Example: Machining of a
                                                         when traveling in interpolation mode. The po-           pressure piece with external
                                                                                                                 thread on the S21
                                                         sition measuring system used also offers ma-
                                                         jor advantages. A resolution of 0.01 μm can
                                                         achieve accuracies in the region of a tenth of a micrometer.
                                                         All the benefi ts of the S12 are demonstrated to their best advantage by
                                                         the example on show. Nowadays, radius dressing devices often guarantee
                                                         the dimensional accuracy of the radius. They prevent fl exible manipulation
                                                         of the radius, however. The S12 is definitely more fl exible in this instance,
                                                         thanks to the high traverse accuracy
                                                         of the guideway and the ability to               FURTHER INFORMATION
                                                          program the radius with the CNC          + + + m i c h e l e .f a h r n i @ s t u d e r. c o m
                                                          control system.                          + + + w w w. s t u d e r. c o m + + +




                                                                                                                          MOTION 01/09                     13
TOOLS & TECHNOLOGY




                                                                                                                                               STAND



S T U D E R i n t e rn a l


From the inside out
STUDER further expands its portfolio with machines produced by COMBITEC, its new subsidiary. The
aim is to increase technical knowhow and application possibilities for internal cylindrical grinding.




S     trong partners for every possible
      task: With the takeover of Com-
bitec AG of Switzerland, STUDER has
substantially increased its grinding
expertise in the internal cylindrical
grinding sector. Whether die grinding,
series production of precision parts for
the aerospace and hydraulics industry
or diesel injection technology, at Sta-
tion 6, STUDER presents three techni-
cally mature production solutions: the
CT-450L, the CT-960 and the S120.


     CT-450L – entry-level
     model for new users
The CT-450L CNC internal and universal
cylindrical grinder for new users is the
light version of the COMBITEC bestsell-
er CT-450. With a wide range of applica-
tions, the CT-450L is equally suited to     Innovative injection technology: Just one of many uses in the application area of internal cylindrical grinding

universal internal grinding applications,



                                            grinding collet chucks and machining brittle hard materials. Special features are
                                            the linear spindle arrangement, use of either one or two belt spindles with speeds
                                            of between 28,000 and 60,000 min -1 and cross-slide design. The CT-450 provides
                                            a range of expansion options, such as a C-axis for grinding all types of threads.


                                               CT-960 – a high-end universal machine
                                            The internal, universal and radius grinder CT-960 is a high-precision machine,
                                            with a B-axis swivel to 91 degrees. A turret for up to four spindles permits effi -
                                            cient grinding of small to medium-sized workpieces. In this particular design,
                                            the machine is suited for universal grinding tasks as well as specifi cally for grin-
                                            ding complex workpieces of brittle hard materials like carbide, ceramics or sap-
                                            phire. The optimum stability and rigidity of the CT-960 also permit grinding die
                                            with radii, cones or path contours. The finished workpieces have polished surface
The light version of the CT-450:
The entry-level CT-450L                     quality. An optional CNC-controlled C-axis is available for grinding threads or




14        MOTION 01/09
                                                                Excellent: The
                                                                 STUDER S120
                                                                    combines
Internal cylindrical grinding: Efficient machining of         productivity and
high-precision small parts                                          flexibility



non-circular shapes. Sim-CT software                    dent grinding tasks. Optimally suited for an efficient machining of high-precision
helps with programming, set-up and                      small parts, it is well established in large batch production. Typical applications
simulation.                                             are in the area of hydraulic components and increasingly in medical technology,
                                                        for example grinding ceramic balls for hip joints. Different handling systems can
   S120 – a speedy                                      be integrated via the well-defined loading interface without too much effort. The
   production machine                                   automated solution on show perfect-
The S120 production internal cylindrical                ly combines productivity with flexibil-           FURTHER INFORMATION
grinding machine is the ideal compact                   ity and in addition, it impresses with    + + + m i c h e l e .f a h r n i @ s t u d e r. c o m
internal grinder for one or two indepen-                short retooling times.                    + + + w w w. s t u d e r. c o m + + +




                                                                                                                                MOTION 01/09              15
TOOLS & TECHNOLOGY




                                                                                                                                            STAND



SERVICE Qualit y


Fountain of youth for machines
Anyone who is familiar with possible wear phenomena starts to think about the health of his
machine. A professional overhaul extends its service life.




H    igh blood pressure is the number
     one cause of illness in most indus-
trialized countries. If not detected and
                                               Servicing with System TM

                                                 More than 100 testing and
                                                                                        Life Cycle Monitoring

                                                                                        The test measurements are
                                                                                                                                Diagnostics and
                                                                                                                               recommendations
                                                                                                                              Information on the current
                                                    measuring points                     evaluated by specialists            state of the grinding machine
left untreated, it can lead to serious con-
sequences such as heart attacks and            Maintenance cycle: Professional machine diagnostics in three steps
strokes. Yet high blood pressure cannot
be felt; only health checks can supply
the information as to whether it is high-
er than it should be even though every-           Preventive SCHLEIFRING Service
thing appears normal. If caught at the         SCHLEIFRING machines are similar to our bodies in this respect: systematic
right time, medicines or a preventive          servicing carried out by SCHLEIFRING SERVICE (which can be compared to rou-
change in lifestyle can help. We often         tine checks by the doctor) extend machine running times and availability and in
do not realize how important our health        addition improve the grinding result. Preventive servicing documents the current
is until it is too late.                       state of the machine. We recommend an annual service with SystemTM. Using
                                               this, SCHLEIFRING SERVICE checks more than 100 points on a checklist and
                                               measures the geometric values and the hysteresis. All the wear parts in the ma-
            New from old: An assembly before
            and after overhaul                                 replaced as a preventive measure. In addition to this, SERVICE
                                               terial list are repla
                                               diagnostics and life cycle monitoring provide valuable insights into the condition
                                                                machine and recommend that corresponding precautions are
                                                of the grinding m
                                                               tha
                                                   taken. More than 3,000 satisfied customers are already enjoying the benefi ts
                                                             Check. The specialist knowledge of the SCHLEIFRING experts
                                                  of SERVICE Che
                                                                 can avoid cost-intensive machine down times, particularly in
                                                  means that you c
                                                        economica
                                                  these economically diffi cult times.


                                                                         Good and beneficial
                                                                         After a complete overhaul by SCHLEIFRING SERVICE the ma-
                                                                             chines once again operate just as precisely and reliably as
                                                                             new machines. The modular overhaul system thus works
                                                                             rather like a fountain of youth. And the process is even more
                                                                             beneficial. The cost of a complete overhaul is between 40 and
                                                                             70 per cent of the price of a new machine.
                                                                         And by the way: more than 100 overhauls are carried out an-
                                                                         nually, using nothing but SCHLEIFRING original components.
                                                                         They are only done in
                                                                         the relevant produc-                       FURTHER INFORMATION
                                                                         tion factory of the                +++ sandro.botazzo@ser viceag.net
                                                                         SCHLEIFRING Group.                 + + + w w w.s er v ic e ag.ne t + + +




16      MOT ION
        MO
        MOTION 01/09
                                                                                                                                             STAND



M I K R O S A K R O N O S S 12 5


Fit for every challenge
In the high speed grinding of injector needles the MIKROSA KRONOS S 125 demonstrates an
unusually flexible ability to adapt to the grinding task.




T    he KRONOS S 125 centerless ex-
     ternal cylindrical grinding machine
is designed with a special construction
                                                                                                                                  Two workpieces are
                                                                                                                                  machined simultane-
                                                                                                                                  ously in two different
principle for the use of the CBN grin-                                                                                            operations with CBN
ding technique. It is based on a ther-                                                                                            wheels using the an-
mally stable and vibration-damped                                                                                                 gular plunging pro-
moulded mineral machine bed. The                                                                                                  cess. The cycle time,
cross-slide systems that are built onto                                                                                           including a dressing
this bed for the grinding and regulating                                                                                          component, is less
wheel side make the centerless grin-                                                                                              than 13 seconds. The
ding machine enormously versatile.                                                                                                workpieces are trans-
The large number of variations, rang-                The angular plunging process: Simultaneous grinding of injection nozzles     ported and sent on
                                                     with CBN wheels using different operations on the KRONOS S 125
ing from throughfeed grinding and                                                                                                 using a paced triple
plunge grinding to reciprocating grin-                                                                                            gripper system.
ding including angular plunging, cycle               One of the machine’s special highlights is the dressing system for the CBN
changing and offset grinding.                        wheels. This uses software that MIKROSA has developed in-house. It uses in-
                                                     tegrated sound sensors in two directions to set the dressing start points. This
   Two operations at once                            guarantees a preset dressing depth, not exceeding three μm, on the surface and
At the 2009 Grinding Symposium,                      the shoulder of the CBN wheel.
MIKROSA is demonstrating the ma-                     A standardized handling system uses the ‘keyhole principle’ to transport the
chine’s versatility, using the machining             workpieces into the machine and out again. External handling systems such as
of injector needles (Ø 4.0 × 48 mm) in               palletizing machines can easily be connected via an interface. Centerless precision
a high-speed process.                                – if all its process technology features are fully utilized, the potential of the KRONOS
                                                     S 125 is enormous. The highest quality and productivity, the ability to process a
                                                     wide variety of different materials and
                                                     the use of versatile grinding techniques                          FURTHER INFORMATION
                                                     – MIKROSA grinding machines meet                            +++ irina.hafner@mikrosa.com
                                                     every requirement of the market.                            + + + w w w.mik rosa.com + + +




                                                           DESIGN HIGHLIGHTS
                                                     Operation 1                                               Operation 2
                                                       CBN grinding by angular plunging                           CBN grinding by angular plunging
                                                       Pregrinding the shoulder                                   Contour grinding
                                                       Pregrinding the tip                                        Finishing the face
Vast potential: The KRONOS S 125 was designed from     Securing with a pressure roller
the start with CBN grinding in mind.




                                                                                                                                   MOTION 01/09       17
  Meister Abrasives AG · Switzerland · www.meister-abrasives.com




Meister Abrasives
Make A Quality Decision               International
                                                                                                                              STAND



S C H AU D T S h a f t G r i n d S


The perfect shaft
Transmission shafts up to 650 millimeters long are the province of the SCHAUDT ShaftGrind S
with tilting spindle technology




T    he SCHAUDT ShaftGrind S is de-
     signed to machine a variety of shafts
efficiently. It has WOP-S programming,
which is based on the Siemens 840D
control panel and helps to generate sur-
face contours such as polygons, ellipses
and free profiles with ease. The machine
                                             Efficient machining
is also eminently suitable for high-speed    taken care of:
                                             Machine configura-
peel grinding (HSP) processes and slot
                                             tion of the ShaftGrind
grinding with CBN.                           S with tilting spindle
                                             that can be swung in

   Machining transmission shafts                                                                     Outstanding results: The ShaftGrind S
Seats for transmission shafts are usu-                                                                      has cutting speeds of 200 m/s

ally ground in an indexing process, ei-
ther by straight plunging or high-speed
peel grinding. The ShaftGrind S with its     with wear-free drives enables the tool spindle to be positioned with extreme pre-
S2 tilting spindle enables different         cision and at the same time maximizes service life. This ensures the most accurate
widths of grinding wheel to be used and      grinding results, even in the case of camshafts. The CamGrind S version of this
permits the interpolation of undercutting    machine is already used successfully for camshaft grinding.
and plunge cutting with an electroplated
grinding wheel. This markedly increases
the productivity of the machine. When                           ADVANTAGES AND PERFORMANCE
high speed plunge grinding with CBN,
                                                             Machining of round and non-round materials up to 650 mm long,
the ShaftGrind S reaches cutting speeds
                                                             weighing up to 50 kg
of 200 m/s. This, together with the car-
                                                             Programming with WOP-S is quick and easy
bon-carrier system of the machine,                           Hydrostatic guide for the X axis (optional extra)
makes the process even more produc-                          Moulded mineral machine bed (Granitan® S 103) with optimized damping
tive. The ShaftGrind S is designed for                       properties and extremely high thermal stability
lubrication with emulsion or oil in com-                 Technical specifications
bination with CBN grinding wheels.                           Sinumerik 840D controller
Grinding wheels that are 480 millimeters                     Integral SPEED-LOAD loader (option)
in diameter guarantee long tool life. An                     Grinding length/tip height: 650 mm / 175 mm
optional hydrostatic guide for the X axis                Spindle configuration
                                                           Grinding wheel diameters large/small wheel: 480 mm / 140 mm
     FURTHER INFORMATION                                   Grinding wheel widths large/small wheel: 80 mm / 70 mm
                                                           Output using large/small wheel: 40 kW/8 kW
+++ irina.hafner@schaudt.com
                                                           2 grinding spindle locations (one spindle can be tilted)
+ + + w w w.schaudt .com + + +




                                                                                                                 MOTION 01/09                19
TOOLS & TECHNOLOGY




                                                                                                                                STAND



S C H AU D T C a m G r i n d L 2


Synchronicity wins on points
The SCHAUDT CamGrind L2 with swivel-in spindle technology and specially-designed
speed profile machines two cam contours synchronously – main and auxiliary machining
times are drastically reduced.




T     he     SCHLEIFRING
      SCHAUDT shows the latest devel-
opment of the CamGrind L at Station
                                       company
                                                              ADVANTAGES AND PERFORMANCE
                                                            Simultaneous machining with two grinding wheels reduces working times
10. The current machine concept is de-                      Reduction in the auxiliary times by one tool-change procedure
signed to meet the requirements for                         Low marginal costs for an additional investment with increasing production
                                                            quantities
mass production of series components
                                                            Portal loading system or integrated loader SPEED-LOAD (option)
– with the greatest possible fl exibility
and ease of refi tting. The two-cross-                     Technical specifications
                                                            Sinumerik 840D control
slide version with its special speed
                                                            Grinding length/maximum height: 800 mm/220 mm
profi le makes it possible to machine
two offset cam contours at the same                       Spindle configuration
                                                            Grinding wheel diameter large/small wheel: 480 mm/250 mm
time in one clamping. The new hydro-
                                                            Grinding wheel thickness large/small wheel: 80 mm/55 mm
statically suspended workhead even
                                                            Output large/small wheel: 40 kW/30 kW
permits, with optimum machine spec-                         Three grinding spindle positions (one swivel-in grinding spindle)
ifi cation with four grinding spindles,



                                                                                                             synchronous grinding of in-
                                                                                                             clined cam radii. A forward-
                                                                                                             looking machine concept.


                                                                                                                A successful design
                                                                                                                principle
                                                                                                             Know-how of camshaft grin-
                                                                                                             ding has for years been based
                                                                                                             very successfully on the WOP-
                                                                                                             S programming system. High-
                                                                                                             resolution glass scales guar-
                                                                                                             antee the accuracy of the
                                                                                                             X-slides. Hydrostatic guides
                                                                                                             for the slides and the use of
                                                                                                             the swivel-in spindle technol-
                                                                                                             ogy round off the well-thought-
                                                                                                             out concept to perfection.
                                                                                                             In this way, the new CamGrind
Fast and simple: Complete finishing in just one clamping                                                      L2 is suitable for cylindrical




20       MOTION 01/09
                                                                                          Deep insight: [1] Example
                                                                                          of a machine configura-
                                                                                          tion with a swivel-in
                                                                                          grinding spindle [2] View
                                                                                          of the inside of the
                                                                                          CamGrind L2 with the
                                                                                          two-slide version




[1]                                        [2]



and non-circular grinding as well as for
keyway plunge grinding and HSP-grin-
ding with CBN. On this type of machine,
only CBN tools with ceramic, galvanic
or metallic bonding are used.



      FURTHER INFORMATION

+++ irina.hafner@schaudt.com
+ + + w w w.schaudt .com + + +                    Finished: A camshaft after the grinding process




                                                 When clamping becomes critical …
                                                 Extraordinary applications demand extraordinary solutions.
                                                 Many workpieces cannot be properly clamped by virtue of
                                                 their unique characteristics. We develop targeted customized
                                                 chucking systems.

                                                 FORKARDT SCHWEIZ GMBH
                                                 Industriestrasse 3, CH-8307 Effretikon
                                                 Tel. +41 52 355 31 31, info-ch@forkardt.com
                                                 an ITW Workholding Comp




                                                                                                                     W W W.FORK ARDT.CH
                                                                                          Highest quality and precision within the μm range
                                                                                                                      MOTION 01/09   21
TOOLS & TECHNOLOGY




                                                                                                                                             STAND


STUDERflexible


Seven at one stroke
With the upgrade to three cross-slides, the unique combined machining system STUDER S242
has become the most flexible hard fine machining center available.



                                                                           confi guration possibilities for external and internal grinding
                                                                           (with up to three internal grinding spindles). External or internal
                                                                           hard turning, hard reaming, milling (with up to twelve driven
                                                                           tool positions) and drilling all benefi t from the wide range of
                                                                           configurations. Equipped with two cross-slides, the S242 has a
                                                                           center distance of 400 and 1000 millimeters. With the three cross-
                                                                           slide version, an additional variant with a center distance of 800
                                                                           millimeters is available. Unrestricted chip removal when hard
                                                                           turning is ensured by the inclined GRANITAN ® machine bed. A
                                                                           chip conveyor takes care of swarf discharge.


                                                                              Quick retooling
Flexible and multi-functional: S242 with three cross-slides (external      The S242 is mainly used in the sectors of machine tools and tool
grinding, turret, internal grinding turret)
                                                                           making, pneumatics/hydraulics and the electrical/electronic
                                                                           sector. High fl exibility of the machine and fast retooling with a


A      range of capabilities that is second
       to none: ongoing continued devel-
opment has meant that nowadays the
                                                          synchronous opposed spindle on the tailstock (W-axis) makes the S242 an in-
                                                          teresting proposition, also for contract manufacturers who machine mainly in-
                                                          dividual components (part families) and small lot sizes. Newly developed control
STUDER S242 is capable of at least                        measuring cycles with a measuring probe mounted in the revolving turret allows
seven machining processes: external                       the automatic calculation of insert wear. This process allows measuring data to
hard turning and grinding, milling of                     be recorded and printed. The well-proven in-house design STUDER easyLoad
small grooves, internal hard turning and                  XL is offered for workpiece automation. Combining the machining processes of
grinding, external thread turning, drill-                 cylindrical grinding and hard turning with parallel grinding spindles and a turret
ing and hard reaming. This means that                     guarantees productive, accurate and reliable complete machining of workpieces.
the S242 is capable of machining spin-                    STUDER demonstrates these processes
dles and guide pillars, pump pinions,                     visually during the Grinding Symposium                  FURTHER INFORMATION
armature shafts, tool holders and other                   with machining shafts and chuck compo-           + + + m i c h e l e .f a h r n i @ s t u d e r. c o m
specifi c components, among others.                        nents at Station 11.                             + + + w w w. s t u d e r. c o m + + +
Complete machining of a variety of
workpieces in a single clamping makes
increases in productivity of up to 70 per                       FLEXIBLE, PRODUCTIVE, ACCURATE, RELIABLE
cent a real possibility.
                                                             Less production time and down time due to quick retooling of the machine
     Wide range of configurations                             High positional and rotational accuracy
                                                             Complete machining in a single clamping
The S242 has parallel grinding spindles,
                                                             Appropriate surface structures
a turret as well as two or three cross-
                                                             In-process measuring of diameter and length
slides. This results in ten or rather 15




22       MOTION 01/09
                                                                                                                                                                                                                               STAND


STUDERintelligent


Intelligent software pays off
StuderTechnology optimizes the grinding process – and increases the efficiency of universal
cylindrical grinding machines by 50 per cent or more.




                                                 Achieving the best with StuderTechnology
I   ntelligent software makes it possible:
    machine operators can once again
concentrate on their key task – the quick,
                                                                                                               Documentation
safe and simple generation of a grinding                               8 : 24 : 00
                                                                                                               Optimization time                                                                                           – 25 %
program. At Station 12, STUDER dem-                                    7 : 12 : 00                             Dressing time
                                                                                                               Grinding time
onstrates with the S31 and S33 univer-
                                                      Time [h:min:s]




                                                                       6 : 00 : 00                             Programming
sal cylindrical grinding machines how                                  4 : 48 : 00
StuderGRIND software and the Studer-                                   3 : 36 : 00
Technology module can contribute to                                    2 : 24 : 00                                       – 90 %                                           – 75 %
reducing cycle times by 50 per cent.
                                                                       1 : 12 : 00

                                                                       0 : 00 : 00
     Everything at the                                                                               s                       h                          s                       h                          s                       h
                                                                                                 lue                  Te
                                                                                                                         c                          lue                  Te
                                                                                                                                                                            c                          lue                  Te
                                                                                                                                                                                                                               c
     push of a button                                                                         va                    er                           va                    er                           va                    er
                                                                                         c al                tu
                                                                                                                d
                                                                                                                                            c al                tu
                                                                                                                                                                   d
                                                                                                                                                                                               c al                tu
                                                                                                                                                                                                                      d
                                                                                    ir i                 S                             ir i                 S                             ir i                 S
Some of the tasks of a machine opera-                                         E   mp 1 unit                                      E   mp 10 unit                                     E   mp 100 unit
tor are to choose the appropriate tool-
ing, set up and retool the machine               StuderTechnology versus empirical values (after optimization): The software is most beneficial for small and medium
                                                 quantities. Example: a shaft is to be machined on three diameters. The surface accuracy should be Ra 0.3, the
quickly, develop the grinding process            roundness no more than 1 μm. A total of six values are measured. When grinding with empirical values the tolerances
and grind accurate parts. He should              were not achieved and time-consuming optimization was necessary

be able to leave everything else to
the StuderGRIND CAM software and                 automatically calculates the process parameters. At the push of a button, the
StuderTechnology. He only has to enter           operator learns which in-feed speeds, changeover points, dressing amounts and
the type of material, specifi cation of the       spark-out time the system recommends.
grinding wheel, type of dressing tool
and certain other factors. The software             Profiting from the knowledge of many
                                                 Behind all these intelligent functions is a technology database with invaluable
                                                 expert knowledge. It makes sure that the machine control is always able to choose
                                                 the best available data. Unlike most operators who often habitually work with
                                                 the same standard values and who rarely manage to keep to the tolerances on
                                                 their first attempt. Such a process is ineffi cient and requires time-consuming
                                                 optimization procedures. However, if StuderTechnology is used, near-optimum
                                                 values are reached straight away, resulting in reduced set-up times and grinding
                                                 times lowered by up to 25 per cent. In addition, the optimization time is often
                                                 zero and costly errors hardly ever happen. StuderTechnology with its many and
                                                 various functions like virtual machine set-up
                                                 and program simulation result in an early                                                                                              FURTHER INFORMATION

Graphic visualization: User-friendly work with
                                                 detection of errors and is additionally ex-                                                                             + + + m i c h e l e .f a h r n i @ s t u d e r. c o m
StuderTechnology                                 tremely user-friendly.                                                                                                  + + + w w w. s t u d e r. c o m + + +




                                                                                                                                                                                                               MOTION 01/09            23
TOOLS & TECHNOLOGY




                                                                                                                        STAND



E WAG C O M PA C T L I N E


Compact? Great!
The EWAG COMPACT LINE scores with its compact design, ergonomic operation and its
integrated robot system for flexible manufacture of inserts.




T     he EWAG COMPACT LINE is de-
      signed for the fl exible and highly
precise manufacturing or resharpening
of indexable inserts in all materials.
Whether the material is carbide, cer-
met, ceramic or super-hard CBN/PCD
– the CNC grinding machine meets all
of the requirements for precision and
speed – especially with the realization
of complex workpiece geometries. The       Ergonomic: Control elements and machine      New measures: All grinding programs can be
machine is fi tted with the new CBN/        interior are accessible from one position    programmed on the touch screen panel

PCD module for grinding super-hard
materials and now also for machining
diamond cutting materials, as EWAG         clamping systems are mechanically identically installed on the B-axis and are
demonstrates at Station 13.                identified by a ‘plug and play’ system. The result is maximum flexibility and
The COMPACT LINE sets new standards        shortest changeover times.
in small spaces with compact construc-
tion, ergonomic operation and an inte-        Dressing, regenerating, crushing
grated robot system. Inside the ma-        The ‘three-in-one’ sharpening unit: dressing – regenerating – crushing provides
chine, everything is positioned close to   perfect grinding wheel concentricity and high repeat accuracy of processes. 3D
the working B-axis; the travel ranges      measuring of workpieces in one clamping ensures the required tolerances are
for axes and robots are thus kept to a     met starting with the first part. Loading is carried out with the integrated 6-axis
minimum, cycle and down times are          FANUC robot which increases the level of machine automation and permits
shortened considerably and productiv-      autonomous multi-shift operation. The
ity is increased. The entire machine       COMPACT LINE which incorpo-
interior as well as all control elements   rates 5-axis CNC kinematics,
are accessible from one position.          direct drive of the grinding
                                           spindle and linear technology
     Fast, accurate, autonomous            allows users to effortlessly
A rapid change system allows the op-       keep pace with changing mar-
erator to exchange the grinding wheels     ket requirements.
effortlessly at the push of a button.
                                                              EWAG COMPACT LINE:
The HSKE 50 clamping system for                        Grinding in the smallest space
grinding wheels ensures quick and ac-
curate changeover of grinding wheel             FURTHER INFORMATION
sets. The workpieces are fixed to the      +++ thomas.fischer@ ewag.com
clamping device with a tension pin. All    + + + w w w.ewag.c om + + +




24      MOTION 01/09
                                                                                                                               STAND



E WAG E WA M AT I C L I N E


The efficient one
EWAG presents the EWAMATIC LINE at the Grinding Symposium, a tailor-made tool grinding
machine for machining highly complex PCD tools



                                                 PCD. EWAG guarantees highest concentricity requirements and geometric tol-
                                                 erances by using a special chuck which allows automatic tool changing. Fully
                                                 automatic loading of the machine is carried out by a 6-axis robot. Each EWAMATIC
                                                 LINE meets specifi c customer requirements. Superior fl exibility makes a mul-
                                                 titude of grinding operations possible in one clamping, guaranteed by the star-
                                                 shaped grinding head with its repeat accuracy of 2 μm. It can hold up to twelve
                                                 grinding wheels. Once the grinding wheel has been dressed on the machine,
                                                 concentricity and run-out are guaranteed at the highest level. Features such as
                                                 pressure-controlled grinding, automatic grinding wheel regeneration and inte-
                                                 grated measuring cycles with adequate compensation make fully automatic
                                                 grinding of CBN and PCD tools possible. The machine can be equipped with an
                                                 eroding process for the production of PCD tools. Users achieve close shape and
                                                 positional tolerances with effi cient eroding and grinding in one clamping. Three
                                                 criteria are the core of the machine autonomy:
                                                   Automatic feed control
                                                   Integrated dressing of the grinding wheels
                                                   Dimensional measuring directly on the machine

Technology of the future: The operating system
carries out simulation directly on the machine     Functionality
                                                 The EWAMATIC LINE has another big advantage: the user can employ grinding
                                                 wheels of up to 300 millimeters diameter and also the smallest mounted points.


A     t the Grinding Symposium, EWAG
      demonstrates fully automated
machining of PCD/ PCBN equipped
                                                 The machine has a high-speed spindle to reach the cutting speeds necessary
                                                 for mounted points. It permits speeds of more than 20,000 rpm.
                                                 In this set-up, the machine
highly complex round tools on the                optimally grinds so-called
EWAMATIC LINE. The 6-axis CNC grin-              pockets for example, which
ding center has many applications:               are subsequently equipped
machining and regrinding of highly-              with CBN or even PCD blanks.
complex workpieces, rotationally sym-            A new operator panel with
metrical tools, indexable inserts from           hot keys already complies
HSS/carbide as well as the latest cut-           with the standard of tomor-
ting materials, like super-hard CBN/             row. Users are able to carry
                                                 out grinding simulation di-
                                                 rectly on the EWAMATIC LINE
      FURTHER INFORMATION                        with a Windows XP operating
+++ thomas.fischer@ ewag.com                     system installed on a high-
                                                                                  Practical turbo: The high-speed spindle can reach speeds of up
+ + + w w w.ewag.com + + +                       performance IPC system.          to 20,000 rpm without effort




                                                                                                                       MOTION 01/09            25
TOOLS & TECHNOLOGY




                                                                                                                                                     STAND



Micro tools


High-performance double act
The HELITRONIC MICRO and the HELICHECK PLUS are the perfect machine combination from
WALTER for the manufacture and measurement of micro tools of the highest surface quality.




T    he development of micro tools has
     seen a rapid upswing in recent
years. They are used for machining the
smallest components in the electronics            trolled via integral high-resolution measuring systems which
industry and the medical and dental               produce precise movements with simultaneously high dy-
                                                                                                                                               [1]
sector and they require the utmost pre-           namics. The grinding spindle head is equipped with three
cision. Without accurate measuring                grinding spindles guaranteeing a high degree of fl exibility.
technology the manufacture of preci-              A secondary X-axis allows for the precise and automatic
sion micro tools is no longer possible.           positioning of tools to the center of rotation of the C-axis.
At Station 15, WALTER shows how the               Additional guiding and support of the workpieces by hy-                                      [2]
surface quality of micro tools has a              draulically activated steady rests supports with fine adjust-                                  0.2 mm diameter
                                                                                                                                                magnifi ed 50 times
considerable influence on the service              ment ensure high dimensional and rotational accuracies.
life of the machine as well as on the             The machine concept is complemented by an integrated
quality of the workpiece.                         loading system served by a 6-axis industrial robot for work-
                                                  piece loading.
     HELITRONIC MICRO
The HELITRONIC MICRO provides all                   HELICHECK PLUS                                                                             [3]
the prerequisites for highly accurate             Optical, non-contact measuring technologies play a decisive                                  0.2 mm diameter
                                                                                                                                               magnifi ed 400 times
grinding results for tools within the 0.5         role, especially with delicate materials and micro dimen-
to 10 millimeter diameter range. The              sions. WALTER sets new standards with the HELICHECK
machine has six CNC grinding axes                 PLUS. The fourth camera with 400× magnifi cation provides
with linear motors and torque motors              the deciding PLUS element and increases the application
on all rotational axes. All axes are con-         range for tools as small as 0.1 millimeter diameter. Front
                                                  and top light cameras also magnify the object to be mea-
                                                                                                                                               [4]
                                                  sured by 400 times. Even the smallest details become vis-
Ideal conditions: The HELITRONIC MICRO achieves
high-precision grinding results                       ible and measurable. Primarily, it comes down to perfect
                                                      lighting of the micro tools which are barely visible with
                                                       the naked eye. WALTER sharpens your vision by effi -
                                                       cient image processing and easy-to-use measuring                                        [5]
                                                       control. A special edge detection system, optimized                                     Well measured:
                                                       lighting and image enhancement techniques ensure                                        First-class surface
                                                                                                                                               quality with the
                                                       that even high-gloss polished, coated or matt surfaces
                                                                                                                                               HELITRONIC MICRO [1].
                                                       can be measured with high repeatability.                                                The HELICHECK PLUS
                                                                                                                                               magnifies object 50 to
                                                                                                                                               400 times [2 + 3]
                                                                           FURTHER INFORMATION                                                 Result of the image
                                                                                                                                               enhancement technique
                                                                    + + + c h r i s t o p h .e h r l e r @ w a l t e r- m a c h i n e s .d e
                                                                                                                                               with a micro tool
                                                                    + + + w w w.w a l t e r- m a c h i n e s .d e + + +                        Ø 0.8 mm [4 + 5]




26      MOTION 01/09
                                                                                                                                                 STAND



WA LT E R H EL I T R O N I C P O W E R D I A M O N D


Only the cutting edge counts
The two-in-one concept of the WALTER HELITRONIC POWER DIAMOND offers a risk-free
entry into the PCD business.




W        ALTER’s answer to the
         ever-increasing stan-
dard of surface accuracy and
cutting edge quality is the
H ELI T RONI C           P OW ER
DIAMOND. The machine
impresses with a 4-stage
erosion process which                                                    [1]                                              [2]
accurately produces
                                                                         Immaculate: [1] The improved cutting edge quality is clearly visible [2] Edge rounding of
perfect cutting edges                                                    3.9 μm at the PCD tool cutting edge
and extraordinary sur-
face qualities of up to Ra =
0.1 μm when machining PCD
tools. It is quite impressive:
The      HELITRONIC              POWER                                                  Changer with 8 positions
DIAMOND achieves only minimum                                                         The trend is towards an increasing range of geometries
stock removal rates due to a fine ad-                                                    and longer unmanned machining cycles. WALTER takes
justment of power during the erosion                                                      on this development with the electrode/grinding
process. The result is PCD cutting                                                          wheel changer with 8 positions for the HELITRONIC
edges with perfect surface quality and                                                        POWER DIAMOND which holds up to 24 electrodes
greatly improved chip resistance.                                                               or grinding wheels respectively. This ensures ex-
Workpieces manufactured in this way                                                               cellent machining properties of PCD and carbide
                                                   Superior
now almost achieve the quality of                                                                 tools with extremely complex tool geometries.
                                                   quality: PCD step
ground PCD tools.                                  drill and carbide                           When eroding stepped contour tools with different
                                                   full-radius milling
                                                                                      concave contour radii for example, the best-suited rotat-
                                                   cutter with perfect
                                                   surface quality             ing electrode is simply selected.
                                                                            The coolant supply manifold is connected to the electrode/grin-
                                                   ding wheel adaptors. This guarantees optimum cooling at all times during the
                                                   production process when tool grinding and optimum protection when eroding.
                                                   In addition, the tool changer extends unmanned machining time for night-shift
                                                   and week-end operation. The two-in-one concept of the HELITRONIC POWER
                                                   DIAMOND enables fl exible reaction to current production requirements. Auto-
                                                   matic changeover from eroding to grinding, from machining PCD tools to process-
                                                   ing or resharpening carbide tools
                                                   is possible. Furthermore, complete                            FURTHER INFORMATION
                                                   machining of almost all types of                        + + + c hr is t oph.ehr ler @ w al t er- mac hines.de
Head-turner: The changer is loaded with up to 24
grinding wheels                                    tools is also feasible.                                 + + + w w w.w al t er- mac hine s.de + + +




                                                                                                                                         MOTION 01/09                27
TOOLS & TECHNOLOGY




                                                                                                                                    STAND



WA LT E R H EL I T R O N I C To o l S t u d i o


The easy way to produce a tool
The new version of the HELITRONIC ToolStudio grinding software from WALTER is even more
efficient and simplifies grinding of complex tool geometries.




O     nly a few years ago, tools with
      variable helix angles, uneven in-
dexing between the individual cutting
edges and constant flute width across
the body were categorized as special
tools. Nowadays, complex geometries
such as these are becoming part of the
bread-and-butter work of many tool
manufacturers and resharpening com-
panies. HELITRONIC ToolStudio is the
efficient software package for the
HELITRONIC tool grinding machine
series from WALTER. It covers every
aspect of the configuration of tool ge-
ometries.                                              High precision 3D view: Graphic tool simulation with HELITRONIC ToolStudio


     Minimal effort
Using the integrated wizard technol-
ogy, tools can be modeled in a simple
way. The required data input is reduced           ter how small, the tool can be individually tailored. Further key functions:
to a minimum. The system only re-                    ‘Click & Edit’: Simply click on the 3D simulation to see the relevant
quests the most important tool param-                geometries and technology parameters
eters and automatically runs through                 Time saving: Path-optimized calculation of positioning movements
the necessary input screens. At the                  between operations and cutting edges
same time the HELITRONIC ToolStudio                  Safety: Automatic collision check prior to manufacture
software accesses WALTER’s knowl-
edge database which stores important                 Tool design made easy
tool grinding experience and helps to             The modular design of the new version of HELITRONIC ToolStudio permits
find a speedy solution for all produc-             variable and individual configuration of all important parameters. Using the
tion tasks. The software complements              modular principle, any number of operations can be added or copied – a huge
the entries with relevant geometry and            advantage when designing tools. All this extra flexibility comes in handy when
technology parameters such as grin-               processing step tools (for example step drills or stepped milling cutters).
ding wheel sets and grinding feed                 WALTER has improved the tool wizard for step tools so that it can now be re-
rates, for example. Based on the basic            started at any time even after manually adding or copying individual operations.
tool model created and high-precision             The amount of work required by the operator has been considerably reduced;
3D simulation which is updated for                with just a few clicks he can replace an existing drill cutting edge on a special-
each and every modifi cation – no mat-             ized step drill.




28      MOTION 01/09
Virtual probing: HELITRONIC ToolStudio records individual diameters and steps as   Replaced with a few clicks: Drill cutting edge using the example of a special tool
well as the entire profile contour                                                  with variable helix design and two steps




   Useful touch functions                               tribution of measuring points can be freely confi gured. While the tool param-
In the production of step tools on                      eters are being defi ned, the HELITRONIC ToolStudio software calculates the
WALTER machines two particular prob-                    flute shape with specifi c focus on all the determining factors. The path of the
ing functions of the software are very                  helical angle, the radius of the grinding wheel bond or the angle of the grinding
helpful. One serves in the alignment of                 wheel are just some examples. Time-consuming checking of the flute shape is
coolant holes and measures the con-                     not required. Accurately parallel clearance angles and land widths on the step
centricity of the blank. The other scans                are produced without the need for long-winded manual corrections. The capa-
the flute path along the contour of the                  bility of the HELITRONIC ToolStudio
tool. It is possible to check individual                software is unrivaled in the market                             FURTHER INFORMATION
diameters or steps as well as entire                    for grinding software. Visitors to                      + + + c h r i s t o p h . e h r l e r @ w a l t e r- m a c h i n e s . d e
profile contours in this way. The dis-                   Stand 17 can see for themselves.                        + + + w w w.w a l t e r- m a c h i n e s . d e + + +




                                                                                                                                                    MOTION 01/09                      29
MARKETS & TRENDS




L e c t u r e I -1 | M a y 6 , 2 0 0 9 | 14 . 0 0


Production in the global economic climate




                                                                                                  Sucked into the recession: Key industries like the
                                                                                                             automotive sector have been affected



The global economy in recession – expertise and technological leadership secure exports of
high-quality capital equipment even in times of crisis.
By Prof. Thomas Straubhaar



T    here is no doubt that the global
     economy is in a crisis. What is un-
certain is how long the recession will
last and how deeply it will affect indi-            of the recession. The automotive industry, machine construction and the electron-
vidual economies. The bad economic                  ics industry are particularly severely affected.
tidings of recent months do not provide
much hope because, for the first time in               From product manufacturer to systems provider
decades, the slowdown is affecting the              However, there is one piece of good news amidst all the doom and gloom: the
whole world at the same time. Even                  global economic crisis finds German and Swiss industry in a comparatively sta-
emerging economies and exporters of                 ble condition. In recent years, many firms in both countries have undergone a
raw material are facing difficult times.             unique transformation from product manufacturer to systems provider. Instead
The crisis on the financial market has               of just selling machines, electronic devices or vehicles, they are now selling end-
become a global economic crisis. Where-             to-end, innovative solutions with an industrial core packaged in a wide range of
as at the beginning it affected only a few          upstream and downstream services – from planning and organization to manage-
isolated sectors like the lending busi-             ment, operation, financing, insurance, maintenance and modernization. German
ness, now there are hardly any areas that           and Swiss companies have become global market leaders in many industries,
are not being sucked into the whirlpool             offering very attractive high-quality, all-round packages of products and ser-




30       MOTION 01/09
                               THE WHOLE WORLD IS AFFECTED                                                                       SOLUTIONS TO THE CRISIS
   Slowdown in the OECD countries              Slowdown in China
   108                                         115
   106                                         110                                                                                         Stability goals
   104
   102                                         105
   100                                         100
    98                                          95
    96
    94                                          90
    92                                          85                                                                Price level                                   Employment
         98 99 00 01 02 03 04 05 06 07 08 09         98 99 00 01 02 03 04 05 06 07 08 09

   Slowdown in the USA                         Slowdown in the euro zone
   110                                         108
   108                                         106
   106
   104                                         104                                                          Monetary            Fiscal policy        Labor market        Foreign trade
   102                                         102
   100                                         100
                                                                                                             policy                                     policy              policy
    98                                          98




                                                                                           Source: OECD
    96                                          96
    94
                                                94
    92
                                                92
                                                                                                                                   The psychology of expectations
    90
         98 99 00 01 02 03 04 05 06 07 08 09         98 99 00 01 02 03 04 05 06 07 08 09
[1]                                                                                                       [2]
What does the future hold? [1] For the first time in decades the slowdown is affecting the whole world simultaneously [2] There are many factors influencing the
economic equilibrium. Expertise and technological leadership secure exports of high-quality capital equipment, particularly in times of economic difficulty




vices. It is not so much low costs and                             iron curtains have been pulled down and national borders swept away. Interna-
prices that give them their competitive                            tional division of labor and specialization have acquired a new, global dimension.
advantage. Instead, it is their effective                          The links in the value chain have been broken down into smaller and smaller units
organization and effi cient management                              and distributed all over the world. ‘As long as it’s cheap’ became the guiding
of complex international value creation                            principle. It seemed as if everything was possible. The Earth was reduced to a
networks that give them a monopoly                                 flat disk. Long distances and the associated costs apparently no longer played a
position that goes beyond cost leader-                             part in the new economic geography.
ship. Technological leadership enables                             Is the crisis on the financial market and the global recession leading to a re-
them to set the rules and to charge high                           versal of this trend? Has the international division of labor passed its peak? Are
prices with generous margins. It makes                             high export growth rates a thing of the past? And will we now return increas-
local firms less susceptible to short-                              ingly to local rather than global production? It almost looks like it. International
term economic problems. This means                                 sales have collapsed. Emerging economies are facing a lack of demand for their
that many German and Swiss firms are                                consumer goods and raw materials and therefore do not have the money to go
not attempting to offer cheaper prod-                              shopping on the world markets. The absence of power in the American growth
ucts and services than the internation-                            engine is putting the brakes on economic growth worldwide. This is particularly
al competition. Their aim is to be tech-                           true of Southeast Asia and Latin America, regions in which production is heavily
nological leaders, both now and in the                             dependent on the U.S. market.
future. Technological leaders are not as                           Despite all the economic trouble spots, there are enough grounds for optimism for
involved in the cut-throat international                           German and Swiss industry. This view is supported by the German and Swiss firms’
price competition and are not as exclu-                            high level of expertise and technological leadership. Small and medium-sized
sively cost-dependent. They set their                              companies in these countries continue to be favorably positioned with a tendency
own prices. This means that they re-                               towards process-oriented rather than product-oriented innovations. Expertise and
main internationally competitive and                               technological leadership secure exports of high-quality capital equipment, par-
can sell their products and services                               ticularly in times of economic difficulty. Demand for infrastructure investment,
even in times of moderate to serious                               capital equipment, ma-
economic diffi culty.                                               chinery, devices and ap-
                                                                                                      ABOUT THE SPEAKER
                                                                   pliances in the emerging
   The future of the                                               economies of Southeast
   global economy                                                  Asia, the oil-exporting      Prof. Thomas Straubhaar has
The global recession will pass, hope-                              nations of the Arab world    been Director of the Hamburg
fully sooner rather than later. Neverthe-                          and the new EU coun-         Institute of International
less, it is the cause of increasing uncer-                         tries of Central and Eas-    Economics (HWWI) since 2005.
tainty: Will the global economy be the                             tern Europe will continue    His key research areas include
same after the recession? Does the                                 – despite, during and aft-   international economic relations,
global economic crisis spell the end of                            er the financial crisis.      economic framework policy,
globalization? Globalization has swept                             German and Swiss firms        economics of education and
across the world like a hurricane in the                           will soon start to benefit    population economics
last twenty years. Protective fences and                           from it again.




                                                                                                                                                                    MOTION 01/09         31
MARKETS & TRENDS




L e c t u r e I -2 | M a y 6 , 2 0 0 9 | 14 . 4 5


Precision machining, quo vadis?
Grinding processes are a
delicate balance of high
precision and high output.
By Prof. Eckart Uhlmann




C     onventional processes in grinding
      technology are under constant pres-
sure to improve still further in answer to
the increasing performance of alterna-
tive cutting techniques. What we see is
that on the one hand, processes with
geometrically determined cutting are
competitive in the fields of cylindrical,
surface and profile machining because
they have great flexibility, high metal
removal rates and low consumption of
resources. On the other hand, the poten-
tial offered by metal removing pro-
cesses is their high process reliability
when machining complex contours to                    Opportunities for grinding
                                                      technology: Technologi-
the highest quality specifications.                    cal innovations secure
                                                      competitive advantages

     Sustainable production
The delicate balance between output
and precision provides an opportunity
for grinding technology. Against a back-
ground of runaway proliferation of tech-            resources assigned to specific operations largely determine the flexibility and
nological innovations, there are com-               suitability for innovation of manufacturing processes. The greater this commit-
petitive advantages that do not depend              ment, the higher the quantitative performance and process reliability that can be
on performance and precision alone.                 achieved. However, there is also the risk that the required values cannot be reached
Future manufacturing strategies will                by changing the components or processing conditions. Therefore sustainable
only be successful in the long term if              process design must also integrate new technology into existing process chains
they save valuable resources and can                quickly and reliably.
react flexibly to changing technical and
economic constraints. Only innovative                 Potential for development
companies that are the fastest to imple-            Process improvements depend on three factors, innovative machine technology,
ment new results from research and                  new developments in grinding and dressing tools and improved process condi-
development will be competitive in the              tions. The effi cient introduction of new techniques requires an in-depth knowl-
world markets of the future. The capital            edge of the effective relationships in the grinding process. Only when the inter-




32       MOTION 01/09
                                             EXTERNAL CYLINDRICAL PLUNGE GRINDING                                                                                                   RAPID STROKE GRINDING OF A
                                         Workpiece: 100Cr6 (60 HRC); Grinding wheel: B126 V360                                                                                         NICKEL-BASED ALLOY
                                    without grooves            groove width 5 mm                                 groove width 15 mm
                                                                                                                                                                           100




                                                                                                                                                Specific grinding energy
                                                                      Possible increase in metal
                         1600                                                                      40                                                                      J
     Maximum workpiece




                                                                                                                                                                          mm 3                   Single-crystal corundum




                                                                            removal rate
        temperature




                           ˚C                                                                      %
                                                                                                                                                                            50
                         1200                                                                      20
                                                                                                                                                                            25                      Sintered corundum
                         1000                                                                      10                                                                              ae = 12 μm
                                                                                                                                                                                   vc = 80 m/s
                                                                                                                                                                               0
                         800                                                                        0                                                                          40       80          120 m/min        200
                                5   10        15   mm 3 /mms 25                                         5   10      15   mm 3 /mms 25
                                                                                                                                                                                             Table feed rate V ft
                                                      Related metal removal rate Q‘w


Informative: Slotted grinding wheels produce a higher metal removal rate than grinding wheels without slots                                   Rapid stroke grinding: This gives high metal removal
and do not increase the thermal stresses on the workpiece                                                                                     rates with a low level of damage




actions between the machine, the tool                                wheels without slots and do not increase the thermal stresses on the workpiece.
and the process are known can the en-                                The slotting causes modulation of the machining forces and thus dynamic
gineer combine the solutions offered                                 excitation of the grinding process. This excitation only leads to process instability
by the wealth of innovations on the                                  if the speed ratio of the grinding wheel to the workpiece, multiplied by the number
market with maximum development                                      of grooves, comes to a whole number. For all other speed ratios, although the
potential. He is supported by innovative                             grooving causes greater oscillation amplitudes than are obtained with ungrooved
process models from research and de-                                 grinding tools, they have no signifi cant effect on roughness and roundness when
velopment. An example is the explicit                                used in machines that have high dynamic rigidity.
modeling of process conditions and                                   In rapid stroke profile grinding of materials that are diffi cult to machine, such as
their effects on the grinding process.                               high-performance ceramic and nickel-based alloys, there are currently two chal-
What is the effect on process parameters                             lenges to be faced. These are the analysis and implementation of the interaction
and the work result in external cylindri-                            between kinematic parameters, coolant conditions and the grinding wheel spec-
cal plunge grinding if slots are made in                             ifi cation. Because the grinding energies are lower it is possible to perform rap-
the grinding wheels at certain locations?                            id stroke grinding with a reduced coolant requirement at high metal removal
A research project that is currently un-                             rates and with a low level of damage. However, it is only possible to achieve
derway at the Institute for Machine Tools                            suffi ciently true profiles if the combination of the thermal and mechanical stres-
and Factory Management (IWF) at Berlin                               ses in the critical zone leads to microcrystalline splitting of the abrasive grit.
University of Technology is investigating                            Grinding wheel design therefore depends on full knowledge of the mechanical
this very question. The purpose of the                               fracturing and tribological properties of innovative abrasive grits.
research is to be able to specify the ef-                            Here, too, system-
fective relationships explicitly. To do this,                        atic analysis of the
                                                                                                                               ABOUT THE SPEAKER
the interaction between the tool and the                             potential applica-
workpiece has been modeled in such a                                 tions of innovative
way as to use numeric simulation to                                  products makes a                                     Prof. Eckart Uhlmann is Head of the
quantify the thermal flow density in the                              signifi cant contri-                                  Fraunhofer Institute for Production
workpiece for various groove configura-                               bution in combina-                                   Systems and Design Technology (IPK) in
tions and process parameters.                                        tion with techno-                                    Berlin and holds the Chair of Machine
                                                                     logical studies and                                  Tools and Factory Management at the
                                                                                                                          Institute for Machine Tools and Factory
   Industrial application                                            ever more powerful
                                                                                                                          Management (IWF) at Berlin University
Slotted grinding wheels produce a                                    modeling                               tech-
                                                                                                                          of Technology
higher metal removal rate than grinding                              niques.




                                                                                                                                                                                                  MOTION 01/09             33
MARKETS & TRENDS




L e c t u r e I - 3 | M a y 6 , 2 0 0 9 | 15 . 3 0


Cool and greasy
The Institute for Machine Tools and Production Technology (IWF) at Brunswick Technical
University has researched new approaches for effective cooling and lubricating.
By Dr Hans-Werner Hoffmeister




S     o far, all attempts at substituting
      cooling lubricants in grinding have
failed. Due to the high temperatures pro-
duced during the grinding process it is                        conventional emulsions and oils in surface grinding and external cylindrical
not yet possible to abandon them. On                           grinding. In this context, the grinding forces encountered, the workpiece surface
the contrary, the multitude of grinding                        roughness, the grinding wheel wear and the temperature of the material subject
applications is constantly posing new                          to material removal rate and cooling lubricant were examined.
challenges to the range and design of
coolant systems. Optimum process re-                              Polymer-based cooling lubricants
sults in terms of profile accuracy, grind-                      The researchers ground a nickel-based alloy on a surface grinding machine for
ing wheel life and minimum processing                          the basic experiments with polymer-based cooling lubricant. The variables
times can only be achieved if compo-                           consisted of the material removal rate and the viscosity of the cooling lubricant.
nent, tool, process parameters and cool-                       Comparison measurements were carried out using a six per cent mineral oil-
ing conditions are coordinated.                                in-water emulsion. In all experiments, the coolant was supplied by an open jet
The Institute for Machine Tools and                            nozzle with extended jet. Coolant pressure and coolant amount remained un-
Production Technology (IWF) of Bruns-                          changed. The experiments showed that the preset viscosity of the polymer
wick Technical University studies the                          lubricant largely determines process forces, grinding temperatures and work-
suitability of polymer-based lubricants                        piece surface roughness. Increasing the viscosity resulted in a reduction of the
and liquid nitrate as an alternative to                        process forces generated and minimized the grinding wheel wear slightly. How-




         400                                                                     Process:               surface grinding with the creep feed method
          ˚C                                                                     Cooling lubricant:     emulsion – Hysol RD 6%, Castrol
                                                                                          Polymer A – Viscosity 1 mm2 /s
         300                                                                              Polymer B – Viscosity 2.3 mm2 /s
         250                                                                              Polymer C – Viscosity 6.5 mm2 /s
                                                                                 Quantity of cooling lubricant: 190 l/min, open jet nozzle
         200
         150                                                                     Material:             Inconel 718
         100          Emulsion – Hysol RD 6%                                     ae = 0.5 mm           aed = 0.8 μm/U
                      Polymer A – Viscosity 1 mm 2 /s
                      Polymer B – Viscosity 2.3 mm 2 /s                          ap = 16 mm            qd = 0.8 +
          50          Polymer C – Viscosity 6.5 mm 2 /s
                                                                                 vc = 35 m/s
           0                                                                     Vw = 125 mm 3 /mm
               0            5                 10          15   mm 3 /mms   25
               Specific material removal rate Q’w                                 Grinding Wheel:       89A 60 H 9AV 55



Conclusive: Grinding temperatures measured with thermal elements show a decrease in grinding temperatures with increasing material removal rates




34       MOTION 01/09
                                    Grinding wheel                                  Dressing roll


                                                                                                                           Nitrogen jet




                                                                                                                               MMS jets



                               Force measuring table                              Insulated cryogenic pipe

                           Comparison tests with dry grinding: Special jets convey the nitrogen and the oil mist from the minimal lubrication system to the
                           contact zone




ever, the quantity of heat transferred            removal. Lower grinding axial forces had a positive effect on the dynamic and
to the workpiece increases at the same            static resilience in grinding, resulting in repeatable grinding behavior.
time. Here, a compromise between re-
ducing the grinding temperatures and                 Liquid nitrogen
grinding wheel wear has to be found,              For the effi cient removal of the grinding temperature from the contact zone, the
depending on process line-up and job              team from IWF worked with liquid nitrogen and minimal quantity lubrication as
specifi cation. Evidently, the viscosity           an experiment. In order to be able to discuss the pure cooling effect better,
has no bearing on the surface quality             comparison tests were made with dry grinding. Special jets were used to sup-
when surface grinding. The research-              ply the nitrogen and the oil mist from the minimal lubrication system into the
ers noticed a slight improvement with             contact zone (see picture above). The liquid nitrogen had to be conveyed di-
external cylindrical grinding. Here, the          rectly into the contact zone through an insulated pipe.
cooling lubricant was also supplied via           As expected, the liquid nitrogen reduced the grinding temperature consider-
an open jet nozzle and was not changed            ably compared to dry grinding. Yet no definite improvements could be achieved
during the series of experiments. The             compared with emulsion cooling. Under the same grinding conditions thermal
variation in material removal rate clear-         interaction of the workpiece edge restricted the material removal conditions
ly shows a connection between in-                 for emulsion as well as for liquid nitrogen lubrication. Liquid nitrogen lacks
creased output and increased material             any kind of lubricating effect. During the course of the experiments it became
removal rate. The idea of reducing                evident that the combination with minimal quantities of mineral oil got the best
grinding wheel wear signifi cantly with            results in respect of grinding
high viscosity index polymer lubricants           wheel wear and unaffected                               ABOUT THE SPEAKER
was unsuccessful, however.                        workpiece edge. The current
All in all, the grinding wheel wear was           price of liquid nitrogen, how-
so small for all the material removal rates       ever, and the complex design of                   Dr Hans-Werner Hoff-
processed that there was no difference            jets and suction devices in the                   meister is Deputy Director
between polymer cooling lubricant and             machines prohibit industrial ap-                  of the Institute for
                                                                                                    Machine Tools and
emulsion. However, the polymer cooling            plication at the moment. But we
                                                                                                    Production Technology
lubricant reduced the grinding tangential         can be sure to expect more in-
                                                                                                    (IWF) at Brunswick
force and lowered the grinding output             teresting results about polymer                   Technical University
of the machine spindles required for chip         lubricants in the future.




                                                                                                                                      MOTION 01/09            35
MARKETS & TRENDS




L e c t u r e I - 4 | M a y 6 , 2 0 0 9 | 16 .15


Small cause – big effect
Round is not necessarily round: The knowledge of interaction of dynamic process variables is
a fundamental prerequisite for optimum adjustment of the grinding wheel.
By Johann Noichl




T     he effect of the dressing of grin-
      ding wheels on the workpiece has
already been investigated many times,
and often extremely scientifically.                the opposite direction without the support, the dressing forces caused the thin,
These investigations have usually been             unsupported diamond plate to vibrate. The vibrations were transmitted to the
carried out under laboratory condi-                grinding wheel, and were manifested as spirally-shaped chatter marks on the
tions, which is why the interactions               workpiece. Dressing had in fact not produced a round grinding wheel, but a
which arise during dressing between                polygon with numerous microscopic facets caused by the vibrations.
dressing tool, grinding wheel, grinding
machine and the setting parameters                    Ceramic-bonded CBN
of the process have not always been                Micro-facets also occurred when dressing ceramic CBN grinding wheels with a
adequately taken into account. Their               rotating diamond form roll. In the experiment, the grinding wheels were profiled
effects on the grinding results and the            at a peripheral speed of 60 m/s and put to work creep-feed grinding on a nickel
potential for process optimization have
recently been investigated by the WZL
Aachen in collaboration with TYROLIT
Schleifmittelwerke Swarovski on ce-                                             150
ramic-bonded corundum and CBN
grinding wheels.                                                                                    F dyn                                     F dyn
                                                          Dynamic fl exibility




                                                                                                        y                                                           y

     Ceramic-bonded corundum                                                    90
                                                                                                                 x                                                      x
                                                                                                        z                                                   z
In preparation for an external cylindrical                                                              ^
                                                                                                  85 Hz =
                                                                                60
grinding operation, a ceramic-bonded                                                              40m/s

corundum grinding wheel was dressed                                                                 150 Hz
                                                                                30
with an upright diamond dressing plate.
The grinding results were not impres-                                             0
sive. Despite maintaining set constant                                                0         100 Hz 200           0      20        40         60         80 Hz       100
process variables, it was impossible to                                                           ^
                                                                                       Frequency = speed of the                    ^
                                                                                                                         Frequency = speed of the grinding wheel
                                                                                             dressing roll
produce a clean workpiece surface. As
                                                                                         Grinding wheel: n = 0                       60 m/s                80 m/s
it turned out, the feed direction of the
                                                                                             Roll: n varies
diamond plate had a decisive influence
on the surface quality of the workpiece:
when the diamond dressing plate was
supported by the dresser support dur-
ing transit of the grinding wheel, there                                                                                             40 m/s                40 m/s

were no chatter marks on the work-
                                                   Modal analysis: The process recognizes high resonant vibrations and contributes to a reduction in wheel
piece. Where the diamond rotated in                wear and improvement in the workpiece surface




36       MOTION 01/09
[1]                                                              [2]
[1] Supported: A diamond plate dresses a ceramic-bonded corundum grinding wheel [2] Unsupported: Resonant vibrations from the grinding machine are transmitted
to the workpiece in the form of spiral chatter marks




alloy at a cutting speed of 80 m/s. With              increase in speed. The realization of these ideas makes very great demands on
this process setting it was quite impos-              the grinding machines in terms of their dynamic rigidity. On top of this, the dia-
sible, irrespective of the grinding wheel             mond dressing rolls will have to be used at much higher speeds. This has prompt-
specifi cation, to produce an accepta-                 ed the question of whether it would be possible to dress a CBN grinding wheel
ble surface on the workpiece. It was                  at a lower peripheral speed and then to use it at high cutting speeds. This how-
extremely rough and wear on the grin-                 ever is not possible due to the dimensional error arising as a result of the radial
ding wheel was extremely high. A mo-                  expansion of the grinding wheel.
dal analysis of the grinding machine                  The ideal relationship between the peripheral speed of the dressing roll and that
revealed that both the selected speed                 of the grinding wheel should be in the region of 0.8. In this way we obtain a rough
of the dressing form roll and the speed               wheel surface. This in turn gives good grinding performance and an acceptable
of the grinding wheel lay within the                  service life for the diamond dressing roll. The use of this dressing speed ratio at
range of resonance of the grinding ma-                high cutting speeds also requires dressing units with very high spindle speeds.
chine. Because of the resonance of the
grinding machine itself, the dressing                    Surprising result
roll produced a polygonal grinding                    Now however there has been a surprising result from another experiment with
wheel. When grinding, the micro-facets                ceramic CBN wheels. When creep feed grinding hardened ball-bearing steel on the
broke up and thus generated a high rate               Blohm AGNETA speed-stroke grinding machine, it was even possible to grind the
of wear in the grinding wheels and a                  workpiece at a cut-
poor surface to the workpiece. The so-                ting speed of 200                  ABOUT THE SPEAKER
lution was to use a dressing speed of                 m/s and a very low
80 m/s. This prevented the resonant                   dressing speed ra-
                                                                                   Johann Noichl is Manager,
vibrations, and the grinding results                  tio of 0.4 without
                                                                                   Application Technology and in
improved immediately.                                 causing it any ther-
                                                                                   charge of the test center in the
                                                      mal damage. This             precision grinding sector at the Aus-
   Higher speed                                       result requires fur-         trian Tyrolit Schleifmittelwerke
In practice, ceramic-bonded CBN grin-                 ther verifi cation,           Swarovski KG. Trained as an
ding wheels are normally used at cut-                 but does indicate            electrical engineer at the HTL
ting speeds of up to 150 m/s. Efforts                 that there is poten-         Innsbruck, he has worked since 1974
are being made, however, to increase                  tial regarding prac-         for TYROLIT in the trials, application
                                                                                   technology and marketing sector
machining performance by a further                    tical realization.




                                                                                                                                     MOTION 01/09           37
MARKETS & TRENDS




L e c t u r e I I -1 | M a y 7, 2 0 0 9 | 9 . 3 0


Grinding and dressing with ultrasonics




                                                                                                                                                     Nature as an example: The
                                                                                                                                                   use of ultrasonic amplitudes
                                                                                                                                                  optimizes grinding processes




Additional high-frequency oscillations in the ultrasonic range during grinding and dressing
reduce forces, temperature and the wear on tools – and enhance the surface finish.
By Prof. Taghi Tawakoli




E    xperiments carried out at the Center
     of Competence for Abrasive Tech-
nologies and Precision Workmanship
(KSF) at Furtwangen University of Ap-                       cess. The principle of the technique consists of adding high-frequency (16–40 kHz)
plied Sciences demonstrate that ultra-                      oscillations at amplitudes of two to 30 μm in or transverse to the direction of infeed.
sonic assistance can optimize processes                     In this way, the use of ultrasonics has the effect of significantly reducing feed power,
when cutting metal with geometrically                       chip size, wear on the tools and heat generation, and it also improves the quality
defined or with geometrically undefined                       of the surface. The ultrasonic oscillations reduce the friction between the chip and
cutting edges. Compared with conven-                        the cutting face of the tool. This leads to thinner chips and thereby to a reduction
tional processes, ultrasonically-assisted                   in the cutting force and an improved surface finish when grinding.
grinding and dressing is a hybrid pro-                      To investigate ultrasonic-assisted grinding, Professor Tawakoli and his team de-




Dressing with a static dressing tool and with a rotating form roll
  Ultrasonic-assisted dressing with static dressing tools                                    Ultrasonic-assisted dressing with rotating dressing tools
  Grinding wheel




                                                                  Single-point
                                                                dressing diamond

  Dressing plate
                                                                                               Cup dresser                                                       Dressing roll


Comparison: Using a static dressing tool, ultrasonic assistance can be integrated relatively easily. Using a rotating dressing tool, as is the case with the form roll, it is
more complicated and calls for both know-how and more complex calculations and equipment




38       MOTION 01/09
veloped an addressable workpiece
holder. The ultrasonic oscillation chain                          Piezoceramic
                                                                  converter         Booster      Sonotrode                     Workpiece
consists of a piezoceramic converter, a
booster, a sonotrode and a special work-
piece clamping device (see picture
right). The ultrasonic generator converts
electric current into high-frequency
pulses, which are then converted by a
piezoceramic converter into mechan-
ical oscillations with an ultrasonic fre-
quency of 21 kHz. The sonic amplitude
is amplified by the booster and then by
the sonotrode and is transmitted to the
                                                                                                         Dynamometer
workpiece, which is connected to the
sonotrode. The resultant oscillations of                     Ultrasonic oscillation chain: Example of an experimental set-up
the workpiece in the tool-holder reach
an amplitude of between ten and 30 μm
at a frequency of about 21 kHz.
                                              face of the grain. However, this smooth surface does not have the ideal gripping
  Inspecting the grinding                     properties for creating chips. In ultrasonic-assisted grinding the grains are broken
In numerous inspections of work with a        into fine particles by the low-amplitude ultrasonic oscillations, but not smoothed
variety of tools, grinding wheels and         out. The small sharp fractures on the contact surface of the grain increase its cut-
stock, the research team compared             ting performance in grinding and this led to 30 to 50 per cent reduction in the
ultrasonic-assisted flat grinding using        grinding power required in the experiments. In comparison with conventional
traditional corundum grinding wheels          dressing the additional high-frequency motion of the dressing tool against the
with conventional flat grinding. Burn          grinding wheel in the micrometer range is characteristic of ultrasonic assisted
marks were produced in conventional           machining. In general, it is relatively easy to integrate ultrasonic assistance with a
grinding. In contrast, the workpiece          static dressing tool. By contrast, it is more complicated with a rotating dressing
ground with ultrasonic assistance dis-        tool, such as a form roll, calling for both know-how and more complex calculations
played no sign of thermal damage. The         and equipment.
high-frequency interaction between the
active grains and the high acceleration         Advantages in grinding and dressing
of the workpiece in ultrasonic-assisted         Grinding power is reduced by 30 to 50 per cent
grinding simplifies the material remov-          Improved surface finish, reduction of the Rz values by 30 to 50 per cent
al process. Chips are more easily re-           The surface structure has a different appearance and a higher contact area ratio
moved because micro-cracks in the               Lower temperatures on the surface
contact zone between the grains and the         Optimized chip formation process with shorter chips
workpiece propagate more quickly as a           Less wear to the dressing tools
result of the impacts due to oscillation        Better profile retention
and positively influence the next chip           Reduction in grinding power and temperatures
formation. This reduces grinding forces
and frictional effects. There is less plas-
tic deformation in the contact zone. In           ABOUT THE SPEAKER
addition, the ultrasonic assistance has
a beneficial effect on the finished sur-
face of the workpiece. It is finer and has                             Prof. Taghi Tawakoli is founder and head of the Center of
a higher contact area ratio.                                          Competence for Abrasive Technologies and Precision Workman-
The KSF researchers achieved similar                                  ship (KSF) at Furtwangen University of Applied Sciences. Prof.
                                                                      Tawakoli has over 130 published papers and six patents to his
positive results with ultrasonically-as-
                                                                      credit and has a laboratory ideally equipped for research in the
sisted dressing of conventional and CBN
                                                                      areas of grinding technology, superfinishing, mass finishing,
grinding wheels. With conventional                                    cutting of hard materials and milling
dressing, the tool smooths out the sur-




                                                                                                                           MOTION 01/09    39
MARKETS & TRENDS




L e c t u r e I I -2 | M a y 7, 2 0 0 9 | 10 .15


Compensating professionally
Even worn dressing tools can accomplish accurate grinding tasks, as long as exact
measuring of the tool cutting edge compensates tool errors directly.
By Prof. Wilhelm Schröder




I   n profi le grinding, dressing tools
    sharpen the grinding wheel and pro-
duce the desired grinding wheel pro-
file. Fixed and rotating diamond tools                   curacy. The implications are high procurement costs and long downtimes for
are used for this process, particularly                 installation and set-up. A joint project between BLOHM JUNG and Georg-Simon-
for small lot sizes and reprofi ling of                  Ohm University in Nuremberg comes up with a new approach on how accurate
grinding wheels. These tools are inte-                  grinding results can be achieved even with worn dressing tools by using mea-
grated in dressing systems which can                    surement control.
feature up to three CNC axes. Dressing
systems which allow the dressing tool                      Correction of the tool radius
to swivel around the center of the dia-                 For contour controlled grinding wheel profiling with diamonds, a CAD/CAM
mond radius are of particular benefi t.                  system, such as the GRIPS 32 programming system, normally produces the NC
They enable complicated profiles to be                   program for the desired grinding wheel profile. The radius of the dressing tool
dressed by a single dressing tool with-                 is taken into account by the so-called tool radius correction. For dressing sys-
out colliding.                                          tems with swiveling axis the pivoting angle of the dresser must also be observed
In time, the radius of the diamond cut-                 so that correct tool intervention is always guaranteed. If the dressing tool is
ting edge will wear as a result of grin-                worn, the original diamond radius takes on an irregular and blunt shape. The
ding wheel dressing. It will lose its ge-               tool radius correction performed by the control unit which always uses the
ometry. This geometry error transfers                   ideal unworn diamond radius will lose its effectiveness, resulting in dressing
to the grinding wheel and consequent-                   and processing errors. A dedicated tool correction facility in the NC program
ly to the workpiece. Only regular re-                   takes tool wear into consideration and ensures that a consistently high level of
placement of the dressing tool will                     process quality is maintained. The direct advantages of this kind of wear com-
therefore guarantee high process ac-                    pensation are:




[1]                                                      [2]
[1] Pivoting angle: Requirements for intervention between dressing tool and grinding wheel (R tool radius, pivoting angle, pressure angle)
[2] Wear compensation: For contour-accurate dressing a correcting motion of the dressing tool on three axes (a, b, c) is required




40       MOTION 01/09
                   Accurate dedication to contour: Innovative measuring of dressing diamonds reduces set-up times and increases accuracy




  Stabilization of process                      aligned with the dressing contour. The effectiveness of the wear compensation
  control                                       is increased and the potential of dressing systems with swivel axis is com-
  Increase of process accuracy                  pletely utilized.
  Increased service life
  Minimum downtime                                  Grinding experiments
  Lowering of procurement costs                 The functionality of the compensation procedure has been proven by several
                                                grinding experiments. To this end, a grinding wheel was profiled with a 2mm
In order to be able to compensate the           radius whereby the worn diamond rotates from –30 degrees to +30 degrees.
wear of the dressing tool, the exact            Through this particular dressing movement the diamond cutting edge is mir-
geometry of the diamond cutting edge            rored onto the grinding wheel during the dressing process. At the same time,
must be known. For this purpose, the            the calculated wear compensation compensates for every error on the dressing
dressing diamond is automatically               diamond. Checking the dressing results on a visual coordinate measuring ma-
measured by a measuring probe. With             chine shows that a contour accuracy within the tolerance range of ±2,5μm has
this reading, the actual shape of the           been achieved in spite of the diamond wear and the off-center diamond posi-
diamond cutting edge is calculated by           tion. If the same experiment is carried out without wear compensation, the
a mathematical process and the form             deviation clearly exceeds ±5μm.
deviation is made available through the
control. The grinding wheel profile is               Conclusion
only dressed accurately if the diamond          Modern control technology facilitates continued use of diamond tools for highly
with its worn cutting edge is aligned           accurate grinding tasks, even
in such a way that grinding wheel and           if they are worn. The service                   ABOUT THE SPEAKER
diamond have a common tangent at                life of the dressing tools is
the desired intervention point. At the          therefore extended and at
same time, the radius deviation has to          the same time the grinding                Prof. Wilhelm Schröder is
be radially compensated on two linear           process is stabilized by com-             professor at the Georg-Simon-
axes. Wear compensation therefore               pensating for the dressing                Ohm University in Nuremberg,
requires a correcting motion by three           wear. As a consequence, us-               where he is responsible for the
CNC axes. This shows the distinct ad-           ers have been given access                fields of Engineering Mechanics,
                                                                                          Machine Dynamics and Machine
vantage of dressing systems with                to a hitherto untapped poten-
                                                                                          Elements in the Mechanical
swivel axes. The swivelability enables          tial for cost reduction and
                                                                                          Engineering Faculty
the worn dressing tool to be perfectly          quality improvement.




                                                                                                                                 MOTION 01/09   41
MARKETS & TRENDS




L e c t u r e I I - 3 | M a y 7, 2 0 0 9 | 11. 0 0


Better understanding of grinding
The WZL (Laboratory for Machine Tools and Production Engineering) is taking part in a
research program to predict the interactions between process and machine during grinding.
By Dr Christoph Zeppenfeld




T    he German Research Foundation
     (DFG) has launched a priority pro-
gram, with the aim of closing the know-
ledge gap regarding the influence on the                    knowledge about the interactions between process and machine requires long
interaction between machine and proc-                      iteration loops when setting up new processes. Understanding the causes of vibra-
ess. It focuses on the interactions at the                 tion phenomena and the prediction of interactions help with the systematic im-
interface between structures and proc-                     provement of manufacturing processes and machines and support efficient and
esses of technical systems. Within the                     effective design of the production process.
framework of the program, the WZL in
Aachen is also carrying out in-depth                           Modeling approach for pendulum and high-speed grinding
research on innovative methods and                         The approach chosen for the analysis and prediction of process-machine-inter-
approaches for predicting the process-                     actions in pendulum and high-speed grinding processes assembles the complete
machine-interactions in pendulum and                       model in two parts. On the one hand, we examine the process regarding the
high-speed grinding processes. Missing                     forces generated during chip removal which are changing continuously. On the
                                                                                     other hand, the machine structure is reacting dynam-
                                                                                     ically to the stimulation. Initially, the models for pro-
                                                                                     cess and machine are built separately and are later
                              Maschinensteifigkeit
                                 Machine rigidity
                                                                                     linked by suitable parameters. The key infl uencing
                    Control cycles                Grinding wheel
                                                                                     factors are identifi ed; generated forces are calculated
                                                                                     and transferred to a suitable machine model. This
                                                                                     model calculates the displacement of the grinding
                                                                                     wheel with the aid of the stored dynamic characteris-
                                                                                     tics of the machine. The positional deviation is then
                                                                                     transferred to the process model. The next calculation
                                     Machine model
                                                                                     step takes the modifi ed process conditions into con-
                                                         Displacement                sideration when calculating the dynamic forces of the
           Forces
                                                                                     process model.
                                     Process model                                   High-speed grinding is characterized by high table
                                                                                     feed rates and low depth of cut, resulting in a large
                                                                                     number of overruns, frequent, very short run-in and
                                                                                     run-out periods and consequently a highly dynamic
                                                                                     performance of grinding forces. The run-in and run-
                                                                                     out periods must therefore be taken into account when
              Process parameters                     Cooling lubricant
                                                                                     modeling. The transmission factors required for force
                                        Surface
                                                                                     simulation are determined on the basis of experiment-
                                                                                     al test runs. In addition, different high-speed grinding
Linked: Key influencing factors are identified, emerging forces are calculated
and transferred to a suitable machine model                                          processes are carried out and generated forces, ac-




42       MOTION 01/09
        SUB-ROUTINE FOR FLEXIBLE CONTACT FORCES                                 MBS MODEL                            ILLUSTRATION OF MACHINE CONTROL


                                                                                                                                Control loop z
                Movable body
                                                                                                                              Control loop y
                                                                                                                            Control loop x



            Contact forces




                                                                                                                      Actual path            New path
                                                             Linear drive with impulse
            Linear guides                                    decoupling
                                                                                             Workpiece table




Components of the MBS machine model: The system calculates the transmission of force of movable bodies towards fi xed structural elements by division of force on
discrete nodes of the model




celeration and structure-borne sound                  chine characteristics in every operating point. The design of the model is based
signals with a sample rate of 20 kHz are              on the machine’s CAD data. An FEM is generated through abstraction of machine
recorded. The data obtained is evalu-                 components and cross-linking the individual parts. The MBS machine model is
ated and stored in a simulation pro-                  built by mapping of the feeding systems and is verifi ed by comparison with the
gram based in Matlab. Initial compari-                measured frequency of compliance operation of the machine. The machine
sons of the measured force paths                      control reacts to positional deviation of the grinding spindle through induced
during run-in and run-out of the grin-                forces with a positional readjustment. In doing so, it also influences machine
ding wheel using the assumptions                      dynamics signifi cantly. The model also takes this factor into consideration.
drawn up in the physical analytical
model show a good correlation be-                         Conclusion and outlook
tween the simulated and measured                      On the basis of the modeling method presented the dynamic performance of the
force path.                                           complete system of machine and process can be recorded and mapped over
                                                      longer travel distances. Looking at it from a holistic perspective can lead to a bet-
  Machine models                                      ter assessment of machining results, which can help to identify and avoid critical
Classic fi nite element models (FEM)                   processes prior to machining. Further research is still needed. One of the areas
describe the behavior of machines in                  we are currently
only one operating point. High-speed                  working on is fur-
                                                                                             ABOUT THE SPEAKER
grinding involves long travel distances               ther detailing of the
with high speeds and accelerations. A                 models. We are also
movable, fl exible multi-body simula-                  expecting a marked                 Christoph Zeppenfeld has been head
tion model of the high-speed grinding                 improvement in the                 of ‘Production Technology & License
machine was therefore built for mod-                  quality of prediction              Support’ at MAN Diesel SE in
eling the machine. It is capable of cal-              with the implemen-                 Augsburg since January 2009. Until
                                                                                         December 2008, he was manager of
culating the transmission of force from               tation of additional
                                                                                         the Manufacturing Technology
movable bodies towards fi xed struc-                   factors like cooling
                                                                                         Research Area at the Laboratory for
tural elements by division of force on                lubricant and the
                                                                                         Machine Tools and Production
discrete nodes of the model. This ena-                material to be pro-                Engineering at RWTH Aachen
bles the recording of the variable ma-                cessed.




                                                                                                                                       MOTION 01/09           43
L e c t u r e I I - 4 | M a y 7, 2 0 0 9 | 11. 4 5


Grinding of components for vane pumps




Manufacturing components for vane pumps and motors demands close machining
tolerances while keeping production costs low.
By Dr August Kästner




V     ane pumps and motors are dis-
      placement devices. After intake,
the medium is enclosed in a defined
working chamber and is transported to                cosity of the medium and the operating pressure, which is between 3 and 180
the consumer, i.e. piston, accumulator,              bar depending on the application. The split is due to the difference between the
hydraulic motor or similar, on the pres-             rotor thickness tolerance plus the number and the geometry of the vanes.
sure side. During the entire working
stroke the vane is pushed against the                  Demands on machines and tools
rotor ring by centrifugal force or a vane            Vane pump and motor characteristics have a direct effect on effi cient process-
ring. Theoretically, the pumped medi-                ing, as complying with lower component tolerances means more diffi cult, i.e.
um cannot escape and the fl ow rate                   more expensive manufacturing techniques. Christian Bauer GmbH + Co. KG of
stays almost constant across the adopt-              Welzheim takes on the role of a consultant and specifi c requirements are care-
ed speed range. Adjusting the rotor ring             fully discussed with their customers. Following these discussions, the compo-
radially from zero eccentricity to max-              nent tolerances have to be increased occasionally.
imum will vary the flow rate while keep-              For effi cient grinding of vane pumps and motors it is imperative that all deter-
ing the speed constant. This makes                   mining production factors are examined in depth. It is also important that very
vane pumps and motors clearly supe-                  rigid machines are used where the natural frequency of machine and grinding
rior to other types of displacement ma-              spindle is far outside the operating frequency range of the grinding process.
chines. As rotors and vanes are moving               This holds true for all movable equipment. When choosing grinding tools, a
between two lateral cover panels and                 suitable abrasive layer must be selected depending on the workpiece and the
are not allowed to touch, the result is              grinding material, with ducts for chip removal if necessary. In the past, Christian
split fl ow. The fl ow loss is adversely               Bauer has carried out much development work in order to increase part capac-
affected by the size of the split, the vis-          ity while at the same time maintaining better quality with regard to dimensions




44       MOTION 01/09
                                                 Well-rounded: Diverse criteria ensure the best products


                                                                                                                        s/     Coolant
                                                                                                                     ine re
                                                                                                                ac h     u
                                                                                                          n / m u f ac t
                                                                                                     t i o an
                                                                                                d uc        /m
                                                                                                                                              Too
                                                                                                                                                  ls
                                                                                           P r o men t
                                                                                                  p
                                                                                           e qui               Introducing innovative concepts

and motors                                                                                                       through contact with machine
                                                                                                            manufacturers, tool manufacturers,
                                                                                                                         research facilities




                                                                                   men t
                                                                                       /
                                                                             spec tion
                                                                       on equip




                                                                                                                                                                       E mploye
                                                                                           Work towards                                    Minimize time
                                                                                           accurate manu-               Customer           expenditure,




                                                               C os t o f in
                                                                                           facture, dedica-                                share in the




                                                             Inspec ti




                                                                                                                                                                          es
                                                                                                                        Product
                                                                                           ted measuring                                   company’s
                                                                                           equipment                     Price             success, training



                                                                                                             Reliable              Minimize
                                                                                                          subcontractors          expenditure

                                                                                                                                                            nd
                                                                                                     Ma                                                 al a o s t s
                                                                                             un fi         te
                                                                                                    n i s r ial /                                 t ion      c
                                                                                                         hed                                  er a a t i ve
                                                                                                                                           Op is t r
                                                                                                             p ar                              in
                                                                                                                  ts                      ad m

                     Precision parts: Avoiding
                    flow losses in vane pumps




  and surface roughness and to extend              Permanently high quality of grinding results
  dressing intervals. The choice of cool-        The machine’s response to temperature changes must be taken into considera-
  ant and the supply jets which deliver          tion if grinding results on a permanently high-quality level within the tolerance
  the coolant directly to the workpiece          range are to be expected. Appropriate technical equipment should be installed
  can also signifi cantly affect the grin-        for this purpose. Another important item is the measuring equipment for each
  ding result. The question whether it           process step including calibration. Training staff to maintain an individual ob-
  would be sensible to use oil or emul-          servations chart or CAQ system within the realms of operator self-inspection
  sion in the processes largely depends          is instrumental in the early recognition of process risks and intervention in the
  on the number of grinding machines             machine control or initiating the dressing process if necessary.
  available at the component manufac-            Constant documentation of the susceptibility of wearing parts like drives, bear-
  turer’s facility. Lastly, a long-term prof-    ings, bellows, electric sensors etc. is needed for preventative maintenance.
  itability study will determine whether         Early replacement of
  a central or stand-alone solution and          these wearing parts dur-
                                                                                                                       ABOUT THE SPEAKER
  whether oil or emulsion should be              ing quiet times will result
  used. Christian Bauer has decided on           in effi cient manufacture
  a central supply of emulsion for all their     as much as multiple ma-
  machines. This particular technology           chine systems and run-                                        Dr August Kästner is
  has been technically perfected and             ning without break peri-                                      Managing Director of
  works with residual particle sizes of          ods.   Cleanliness                          and               Christian Bauer GmbH +
  fi ve to six microns. As a result, the com-     tidiness, low stock levels,                                   Co. KG. The Welzheim-
  pany is able to handle all kinds of grin-      short cycle times, elimin-                                    based company manufac-
                                                                                                               tures disc springs and
  ding materials from high-speed steel,          ating waste, constant im-
                                                                                                               precision parts for vane
  100Cr6, sintered steel to other types of       provements and reducing
                                                                                                               pumps and camshaft
  hardened or unhardened steel, with             set-up time complete the
                                                                                                               adjustment systems
  great success.                                 picture.




                                                                                                                                                                 MOTION 01/09     45
MARKETS & TRENDS




L e c t u r e I I I -1 | M a y 7, 2 0 0 9 | 14 . 0 0


Turning, grinding, honing
The Dortmund Institute of Machining Technology (ISF) examined innovative concepts for
combined machining and internal cylindrical peel grinding.
By Prof. Klaus Weinert




N     owadays, the combined turning
      and grinding process is the pre-
ferred method for internal cylindrical
machining of hardened components.
It combines the advantages of turning                         PROCESS KINEMATICS                             CONTACT CONDITIONS

with those of grinding, i.e. a high                                                     Workpiece
achievable stock removal rate and high
                                                                                        Grinding wheel                                            Grinding wheel
flexibility while maintaining high pre-
cision and surface quality. Over the
past years, the ISF has explored two
                                                                                                                                                   Workpiece
further concepts for internal cylindrical
machining: extending the existing
combined machining process by a hon-
ing process and internal cylindrical
peel grinding.                                                      axial feed rate                                        angle of scrubbing zone
                                                                    workpiece circumferential speed                        width of smoothing zone
                                                                    total radial grinding allowance                        specific material removal rate
     Honing reduces production time                                 effective infeed                                       grinding wheel speed
The basic advantages of honing are                                  axial feed rate                                        workpiece speed
                                                                    effective contact width                                workpiece diameter
reliability, high accuracy and excellent
surface structures. Furthermore, hon-
                                                       High material removal rate: Process kinematics and contact conditions in internal cylindrical peel grinding
ing can reduce edge damage caused
by pre-machining, or even rectify it. In
addition, the process induces residual
compressive stress into the surface of
the component which extends the life                   ciently rigid design it contributes to an improvement in roundness and cylindric-
of the functional surfaces. Expanding                  ity and corrects any position errors. There is no need for a special feed attachment
an existing turning and grinding ma-                   as the machine axes transpose all tangential, radial and axial movements. The
chine with a honing facility thus offers               design of the honing tool permits a split into two processing sides. Different
the possibility to reduce production                   honing stone specifi cations can be used for a variety of processing steps, for
times and to react fl exibly to quality                 example, a honing stone with rough grain for rough machining on the first process-
requirements.                                          ing side and a fine grain stone for finishing on the second side.
The honing tool developed specifi cally                 With combined turning-grinding-honing machines it is possible to process ro-
for the combined turning-grinding-                     tational symmetrical workpieces from blank to finished component on one ma-
honing machine is impressive due to                    chine and in a single clamping. Depending on the required component quality,
its simple design without additional at-               combined machining can consist of turning and grinding, turning, grinding and
tachments for feed or measuring. It is                 finish-honing, or turning, pre-honing and finish-honing.
integral to the machine and in a suffi -                The combined turning, grinding and honing process improves the surface qual-




46       MOTION 01/09
                                                                                                                         TWO PROCESSING SIDES

                                                                                                                  1st processing         2nd processing
                                                                                                                        side                  side




                 Turning                   Honing                    Grinding




[1]                                                                                                             [2]
Combined machining: [1] Three operations on one machine [2] Rigid honing tool with two processing sides




ities of the components with each pro-                  by dividing the grinding wheel into different functions, i.e. a cone-shaped
cess step. The final honing process                      scrubbing zone for stock removal and a cylindrical finishing zone for perfecting
creates the surface structure typical for               surface quality.
honing. With the alternative turning-                   Contrary to grinding, hard turning is characterized by high fl exibility and high
honing-honing process chain this struc-                 material removal rates. A comparison with hard turning proves the advantages
ture has already been achieved after                    of internal cylindrical peel grinding with regard to accuracy and effi ciency. While
the first honing operation. The struc-                   internal cylindrical peel grinding uses an electroplated CBN grinding wheel and
ture shows greater surface roughness                    grinding oil, the hard turning process is carried out dry with a CBN insert. Chip
though, which is reduced by finish hon-                  formation and the circumferential speed of the grinding wheel have a consider-
ing. Both process combinations have a                   able influence on the axial force in the process. Axial force in internal cylindrical
positive influence on the component                      peel grinding is ten times as small as in turning while the amount of stock re-
shape and the cylindricity error ob-                    moved stays the same. The high feed rates in turning also lead to higher surface
tained was less than 2 μm in both ca-                   roughness compared with internal cylindrical peel grinding.
ses. However, the turning-honing-hon-                   Constant striving for increasing productivity and flexibility strengthen efficiency
ing process combination did not achieve                 and competition of a manufacturing business. Demand continues to move towards
the same surface qualities as the turn-                 smaller lot sizes and an in-
ing-grinding-honing process chain.                      creasing selection of op-                     ABOUT THE SPEAKER
                                                        tions while product life cy-
   Internal cylindrical peel grinding                   cles are constantly being
Internal cylindrical peel grinding also                 reduced. To this end, hard-             Prof. Klaus Weinert has been
produces high material removal rates                    fine machining is taking on              head of the Institute of
whilst maintaining excellent surface                    some of these processing                Machining Technology (ISF) at
quality. In this process a specially                    tasks. Thanks to new con-               the Technical University in
shaped grinding wheel moves along                       cepts like the one described,
                                                                                                Dortmund since 1992 and he is
                                                                                                also a member of the research
the borehole by axial infeed. The                       the efficiency of production
                                                                                                association for manufacturing
amount of stock to be removed is only                   processes will continue to
                                                                                                technologies
set once. This has been made possible                   be increased in the future.




                                                                                                                                   MOTION 01/09           47
MARKETS & TRENDS




L e c t u r e I I I -2 | M a y 7, 2 0 0 9 | 14 . 4 5


Intelligent spindles
New grinding spindles for very high speeds reduce the use of
lubricants and increase durability.
By Dr Bernd Möller



P    rocessing small internal diameters
     with optimum cutting speeds re-
quires high rotational speeds. New
GMN spindle ball bearings with very
high speed characteristics permit                                                                                                         Sensors for

250,000 revolutions per minute, for in-                                       Intelligent spindle unit                                         Temperature

stance, with comparatively high spin-                                                                                                            – bearings
                                                                                                                                                 – coil
dle rigidity and load capacity. Opti-
                                                                                                                                                 – coolant
mized lubrication of high-speed
                                                                                                                                               Speed
spindles offers great potential for in-
                                                                                                                                               Tool clamping system
creasing performance. Furthermore,
                                                                                                                                               Vibration
on-demand minimal lubrication lowers
oil consumption and increases service                                   SPIDER
life. In future, integrated data loggers                                • Record data
                                                                        • Monitor spindle
will monitor the condition of the spin-                                 • Monitor process
dle, store the operating parameters and                                 • Transfer measured data
guarantee high availability. GMN has
                                                                                                         SERIAL INTERFACE
a long track record of supplying a wide                                                                  • RS232
range of high-frequency spindles with                                                                    • RS485
                                                                                                         • CAN
speeds of up to 180,000 min -1. How-                                                                     • PROFIBUS
ever, around two-thirds of the spindles
supplied for internal grinding operate
                                                       A lot of knowledge in a small space: Intelligent electronics store sensor signals, process them and report any
with maximum speeds in the 30,000 to                   exceeding of critical values to the overall machine control
90,000 min -1 range.



                                                          250.000 min -1 for small bores
                                                                                 machine tool spindle must have the appropriate load
                                                       To operate effi ciently, a mach
Maximum speed: GMN high-frequency                                                capa
                                                                                 capacity, rigidity and dynamic run-out. In order to guar-
spindles achieve speeds of up to
180,000 min -1                                                                    ante
                                                                                  antee these characteristics even for extremely high
                                                                                   speeds, the GMN development department was
                                                                                   sp
                                                                                     f
                                                                                     faced with extraordinary challenges. Breaking
                                                                                       points are reached due to high centrifugal forces,
                                                                                       a compact design has to ensure subcritical op-
                                                                                       eration with suffi cient distance to the first critical
                                                                                        speed, high-precision hybrid bearings have to be
                                                                                        designed specifi cally for the demands of high-
                                                                                         speed spindles. These challenges were met with
                                                                                        the help of current advances in motor technology
                                                                                    and the use of further developed GMN spindle ball
                                                                                    a
                                                                                 bea
                                                                                 bearings. It is now possible to effi ciently grind small
                                                                             internal geometries with up to 250,000 min -1. The GMN
                                                                             interna




48       MOTION 01/09
                300.000
                                                                                                              Quantity of              Power loss
                                                                                            Dosage element                   Spindle                               G 9L (s)
                                                                                                              lubricant      bearing

                250.000
                                                     Cutting speed




                                                                                                                                                                              Bearing temperature
                                                     [m/s]                                                          Speed




                                                                                                                                                  Motor heat
                200.000                                                                                                     Process forces
                                                                                             Machine
                                                                                             control
Speed [1 min]




                150.000                                                                                                     Spindle drive
                                                                                                                                                    Spindle cooling
                                                                                                                                                        system
                100.000
                                                                                                                                         Stator                 Coolant
                                                                                                                    Speed           temperature                 temperature

                 50.000                                                                                               Lubricating
                                                                                                    Lubrication
                                                                                                      control                                Observer
                                                                                                                      fi lm estimated

                      0
                          0   5   10   15     20      25        30      35    40   45             Bearing monitor
                                       Grinding wheel – Ø [mm]

Synchronous motor: Flexible use of grinding spindles in relatively high rotational       Important criteria for investment decisions: Control of lubricant quantity depending
speed ranges                                                                             on demand




grinding spindles used for this purpose                              ideally requires no more external components. The problems associated with
have a comparatively large and rigid                                 waste oil disposal are also defused. Operating costs of machine tools can exceed
mounting – the speed characteristic                                  acquisition costs several times over if calculated over a normal life cycle. These
n·dm amounts to up to 4.5 ·10 6 mm/min                               costs are therefore a decisive factor for many users when making investment
– and a powerful synchronous motor.                                  decisions. An integrated lubricant cartridge means that high-maintenance ex-
Consequently, they are suitable not                                  ternal components can be dispensed with. The lubricant reservoir only needs
only for special applications at maxi-                               replacing at relatively long intervals. An almost instant dosage of lubricant
mum speeds but can also be used fl ex-                                ensures that the adjustment of the lubricant quantity matches demand based
ibly and effi ciently in a relatively large                           on exact measurements of the bearing. This increases the reliability and effi -
rotational-speed range.                                              ciency of the bearing and reduces the quantity of lubricant needed.

                Integrated lubrication module                          Third generation spindles for machine tool
These days, ball bearings with perma-                                Spindles are also becoming more and more intelligent. Miniaturized electron-
nent grease lubrication or oil/air lubri-                            ics which are integrated in the spindle store the sensor signals, process them
cation are predominantly used in main                                and report any exceeding of critical values to the overall machine control
machine tool spindles. Yet both meth-                                system. Important operating data can be accessed during the entire running
ods have their disadvantages which                                   time of the spindle and can be analyzed with regard to optimizing the process,
can be overcome by an innovative                                     machine and spindle. In addition, the aim is to go for bearing condition mon-
micro-dosing system combined with                                    itoring and consequently early damage detection, based on these intelligent
appropriate lubrication strategies.                                  systems. Evaluating temperature
Compared with today’s oil/air lubrica-                               sensors, position sensors and vibra-           ABOUT THE SPEAKER
tion method, a signifi cant reduction of                              tion sensors will increase precision
the lubricant quantity necessary is to                               and productivity of the production
be achieved and the systematic per-                                  process. Additional sensors, on the       Dr Bernd Möller is
formance limits of grease lubrication,                               other hand, harbor the risk of reduc-     head of the Engi-
i.e. limited usable life of grease at high                           ing the availability of the spindle sys-  neering Spindle
speeds and temperatures, are to be                                   tem further, therefore, as few addi-      Technology division
exceeded. Minimizing lubricant quanti-                               tional sensors as possible should be      at GMN Paul Müller
ties makes ecological and economic                                   employed and for the time being, a        Industrie GmbH &
sense. It facilitates the integration of                             more intelligent analysis of available    Co. KG in Nuremberg
an oil reservoir into the spindle and                                signals should be aimed for.




                                                                                                                                                           MOTION 01/09                             49
MARKETS & TRENDS




L e c t u r e I I I - 3 | M a y 7, 2 0 0 9 | 15 . 3 0


One concept for every site
The Hirschvogel Automo-
tive Group uses a standard
machine concept in all its
production facilities through-
out the world.
By Harro Wörner




E    very year some 200,000 tonnes of
     massive formed components leave
the Hirschvogel Automotive Group’s
factories. The automotive supplier, from
Denklingen in Bavaria, Germany, has an
international presence, with sales of-
fices in the USA, China, Brazil and India.
Three thousand employees generate a
turnover of more than 500 million euros.
This makes Hirschvogel one of the lar-                     A bundle of power: Many vehicles on
                                                           the road have components formed by
gest suppliers in this sector. The com-                    Hirschvogel Automotive Group
ponents are produced by forging, cold
forming, warm forming and combined
processes and weigh between 0.1 and
25 kilograms each. Hirschvogel has suc-                 ties are expected to comply with. Hirschvogel Umformtechnik GmbH in Denklingen
cessively broadened its production ex-                  is the master factory for forming and Hirschvogel Komponenten GmbH in Schon-
pertise to include machining with heat                  gau is the master factory for machining. New components are developed in co-
treatment and now supplies components                   operative partnership with the customer to optimize costs. The customer provides
ready to be installed directly on the cus-              the knowledge of the product and Hirschvogel provides manufacturing expertise.
tomers’ assembly lines.                                 The two can thus work together to develop the ideal components.
The company’s core business is the                      The QM-online quality management system can be used to generate test batch-
large series production of extremely                    es through the company’s own SAP system. All the test machines are connected
complex formed components. It sup-                      to the system. When required, it is possible to export assessments, perform
plies the five product groups, namely                    analyses and even, using the data matrix or clear text, assign the appropriate test
transmission, chassis, drive train, injec-              data to each individual component. As a rule, this is done for components that
tion and engine. Hirschvogel can offer                  have a high added value.
its customers throughout the world, who
include virtually all original equipment                  Increasing standard machine capacity
manufacturers (OEM) plus first and                       Machine planning is a particular challenge for an automotive supplier. The key data
second-tier suppliers, a uniform quality                for a new project and the capacity for series production must already be in place six
standard and identical technologies.                    months before the start of production. Hirschvogel usually receives an order for 80
‘Master factory functions’ specify the                  to 100 per cent of the customer’s requirement with a non-binding quantity estimate.
standards that all the production facili-               This can then vary by another ±15 per cent. These imponderables can only be con-




50       MOTION 01/09
[1]                                                         [2]                                                    [3]
Hirschvogel supplies components for five different groups of products: [1] Chassis [2] Drive train [3] Transmis-
sion [4] Engine [5] Diesel/Gasoline injection




trolled by having a scalable production                       Grinding and measuring
system on the modular principle. Hirsch-                   For grinding, Hirschvogel uses ma-
vogel has opted for a standard machine                     chines from a variety of manufacturers
concept that can produce goods at com-                     in its internal module. The process that
petitive prices with appropriate automa-                   is needed in each case, for example
tion. The decision regarding the best                      centerless cylindrical or non-round
technology for the job is taken during the                 grinding or a combination process, de-
course of the project. The machine is cho-                 termines the machine that is chosen
                                                                                                                   [4]
sen and equipped from standard mod-                        for it. Even though the grinding ma-
ules. This enables Hirschvogel to produce                  chines are supplied with the appropri-
samples by hand that are close to their                    ate technology for in-process measure-
series production counterparts. The re-                    ment or for measuring component
quired capacity must be installed before                   alignment, Hirschvogel uses addition-
production begins. It is only by this means                al forms of analysis and test methods
that the desired Run@Rate and process                      to determine depth of roughness, twist
acceptance can be configured with the                       and the properties of peripheral areas
customer. Capacity is increased by com-                    in the workpiece, and also uses vibra-
missioning duplicate machines and using                    tion analysis. The latter has proven
the corresponding automation.                              worthwhile, particularly in the grinding
                                                           of roller bearing seats.
   Automation concept                                      Hirschvogel requires the future gen-
                                                                                                                   [5]
The automation concept is developed                        eration of grinding machines to offer
from the value stream planning in each                     a considerably higher
case. Hirschvogel usually uses stacking                    potential for cost reduc-
                                                                                                          ABOUT THE SPEAKER
cells or circulating conveyors. The reason                 tion. The machines have
for this is that although direct linking is                to be able to offer much
usually best for a value stream, it is not                 greater versatility of use               Harro Wörner Harro Wörner is
necessarily the most cost-effective solu-                  and the ratio of basic                   CEO of Hirschvogel Kompo-
tion in respect of capacity, as the quan-                  machines to type-spe-                    nenten GmbH in Schongau.
titative data provided by the customer is                  cifi c investment must be                 Since 2002, he has been
not binding and can vary between zero                      better, as the batch sizes               responsible for the global
                                                                                                    production network for the
and a hundred per cent. Only the cost                      and service life of the
                                                                                                    machining of formed compo-
calculation at the end of the project                      products are also in-
                                                                                                    nents within the Hirschvogel
shows whether the automation concept                       creasingly subject to                    Automotive Group
was actually able to optimize the costs.                   change.




                                                                                                                                   MOTION 01/09   51
MARKETS & TRENDS




L e c t u r e I I I - 4 | M a y 7, 2 0 0 9 | 16 .15


Great potential savings




     Al 2O 3: Abrasives such as
     aluminum oxide influence
     grinding and dressing behavior




Diagonal grinding with super-abrasive CBN wheels is not dependent on geometry.
The process reduces grinding time by up to 80 per cent.
By Udo Mertens




O       n all grinding tools, the abrasive
        material used and how it is bond-
ed are of prime importance. Composi-
tions vary depending on the applica-                  Synthetic resin bonding materials are soft grinding universal binders with
tion. Conventional abrasives such as                  phenolic resin and polyimide resin binding agents
aluminum oxide (Al2O3 ) or silicon car-               Galvanic bonds hold the abrasive in a single-layer coat, the thickness
bide (SiC) are bonded in ceramic or                   of which is roughly that of the average grain size used. Tools with this
synthetic resin materials. Super-abra-                type of bond cannot be dressed
sive materials such as CBN or diamond                 Metallic sintered bonds are highly wear-resistant
are additionally secured in metal bond-
ing materials. The type of bonding ma-
terial used and its internal structure
largely determine the grinding and                           TRENDS IN GRINDING TECHNOLOGY
dressing behavior.
                                                        MARKET DEMANDS IN E.G.
                                                        THE AUTOMOTIVE SECTOR
      Ceramic bonded CBN grinding                         Lower noise emissions
      wheels are mainly used in series                    Lower CO2-emissions
      and high-volume production. Their                   More powerful engines
      high metal removal rates and                        Lower consumption
                                                          Greater reliability
      surface characteristics mean that
                                                          Longer service intervals
      they are well suited to high-speed
                                                          Lower purchase prices
      grinding. Dressing is simple




52        MOTION 01/09
Conventional grinding tools are made
entirely of abrasive material. CBN and         GRINDING SHAFT ENDS

diamond grinding wheels, on the other
hand, have a relatively thin coating of
abrasive that is bonded to a carrier ma-
terial. The choice of this material de-
pends on, among other things, the              Straight infeed
                                               grinding
grinding job and the conditions of use.
In addition to good thermal conductiv-
ity and vibration damping it must pos-
sess suffi cient mechanical strength.
The following materials are available:


   Aluminum
   Steel                                       Angular infeed
                                               grinding
   Synthetic resin, with or
  without metal fillers
   Ceramic
   Composites                               Advantage of angular infeed grinding: Circumference and flat shoulder are machined simultaneously



  Examples: Camshaft bearings
To date the use of galvanically bonded
CBN grinding wheels for plunge-cut          to be machined in a single operation. Two grinding processes run simultane-
rough grinding of the bearing points on     ously with differing process kinematics. The advantages are:
a GGG camshaft in a centerless grin-
ding machine has required a support             A shorter grinding feed traverse saves time
bushing, seven grinding wheels and              Shorter contact length at the flat shoulder minimizes the
four spacer rings. It is not economi-           risk of thermal damage
cally feasible to dress the single layer        Reduced loads on the edge of the abrasive coating
coating of these grinding wheels with-
in a few micrometers. Saint-Gobain          Even so, there are disadvantages associated with the angular position and the
Diamantwerkzeuge GmbH & Co. KG has          geometry of the workpiece. A large area of abrasive coating is needed for grinding
therefore developed a grinding tool         the flat shoulder. Since it does not make economic sense to reprofile super-abra-
with a single carrier material which is     sive grinding wheels, a change of workpiece to one with a different profile means
far more durable. All the areas of the      that the CBN tool has to be changed as well. This involves a longer idle time. In
abrasive coating are machined without       addition, CBN grinding wheels with wildly differing geometries have to be kept in
re-clamping and there is no need to         stock – an additional cost factor. This is where diagonal grinding offers great sav-
dress the profiles. These are more eco-      ings potential. The axis of the workpiece is parallel to that of the grinding spindle.
nomical because they have a longer          The angular infeed is achieved by simultaneous movement in the radial and axial
tool life and they cost considerably less   directions. Thus the same tool can be used to grind virtually all geometries on the
to manufacture.                             circumference and the flat
                                            shoulder without the need                    ABOUT THE SPEAKER
  Examples: Crankshaft ends                 to change the geometry of
In practice, shaft ends are machined by     the coating. This is par-
external cylindrical angular infeed         ticularly advantageous for             Udo Mertens is
grinding or infeed grinding with a          short runs. Studies by                 responsible for product
straight cut. In external cylindrical an-   Saint-Gobain have shown                management and product
                                                                                   development for ceramic
gular infeed grinding the grinding spin-    that the processing time
                                                                                   bonded CBN and diamond
dle and workpiece axis are set at a de-     with diagonal grinding can
                                                                                   tools at Saint-Gobain
fined angle with respect to each other.      be up to 80 per cent short-            Diamantwerkzeuge
The angular position enables high flat       er than that required for              GmbH & Co. KG
shoulders and circumferential surfaces      straight infeed grinding.




                                                                                                                            MOTION 01/09       53
MARKETS & TRENDS




L e c t u r e I V-1 | M a y 8 , 2 0 0 9 | 9 . 3 0


The cutting edge industry: tool grinding
In tool grinding, quick decisions and skill are demanded of cutting tool makers, so that short
delivery schedules can be maintained.
By Prof. Wilfried Saxler




W        hen resharpening a metalwork-
         ing tool, the toolmaker has to
decide anew every time whether the
                                                                 ONE STRENGTH OF THE TOOL GRINDING COMPANY IS THE SHORT DELIVERY TIME



costs of sharpening will exceed the
costs of replacement by a correspond-
ing new tool. Take classic twist drills,
for example, these days, companies
set their own diameter limits below
which sharpening is no longer eco-
                                                                      Receipt of order            Delivery date                   Sales
nomical. These limits also depend on
the level of automation of the grinding
centers. No matter what the kinematics                                                                                                    Time

are behind the CNC tool grinding ma-
chine: with fi ve CNC axes, almost all
rotationally symmetrical machining                                                3–10 working days
tools can be ground. Here, apart from
the machine’s automatic handling
system, the fl exibility of the clamping
system has a major infl uence on the
                                                    Advantageous: An order is completed as a rule within a week, but in any case in a maximum of 14 days
economy of the grinding machine’s
operation.
The variety of parts stocked by tool                   Economic rise and fall
grinding companies is extensive. One                There always have been economic downturns, and there always will be. If a
customer order includes a number of                 company depends on a single business sector for its customers, it’s also going
different drill-bits or mixed types of              to experience the ups and downs of this sector itself. This is why it is essential
tools, on another occasion it includes              for tool grinding companies to address a wider audience and serve different
a large number of identical special                 sectors. Generally, tool grinding companies have two decisive advantages:
tools. Given this extreme variation in                  The machine tool mechanic is trained both for the
orders, quick decisions and skill are                   initial manufacture and for subsequent sharpening
demanded of the cutting tool maker. In                  of cutting and machining tools
addition there is the maintenance of                    CNC tool grinding machines are used for sharpening as
short delivery schedules of a week to                   well as for the manufacture of various tools in different numbers
a maximum of a fortnight to be consid-
ered – one of the strengths of these                In this way, a range of different orders can be secured, accepted and processed
companies. But this is exactly where                and the growing market for special tools can be serviced. Most of the major tool
the danger lies: with no orders coming              manufacturers are not suitably equipped for manufacturing these special tools in
in, the turnover drops immediately.                 penny numbers. This gives the tool grinding operators a major advantage. Never-




54       MOTION 01/09
    THE CONDITIONS FOR MANUFACTURING AND SHARPENING TOOLS
                                     Sharpening                                                    Manufacturing
Stock material                         Worn tool (from the customer)                                  Blank (purchased)
Tool drawings                          Generally not present or required                              Not available
                                                                                                      Must be derived and created from the
                                                                                                      workpiece drawing
Preparations                           Visual check, cleaning if necessary                            Possible edge fracture at the end of the
                                       Shaft preparation                                              shaft
                                       Determine amount of wear for grinding stock
                                       Dimensioning on measuring machine
Clamping accuracy                      Dependent on previous history                                  Dependent on blank (can be influenced)
(circular runout)                      (cannot be influenced)
Programming expenditure                Dependent on geometry                                          Dependent on geometry
                                                                                                      Control possibility using simulation
Defining the position of the            Complicated tool probing operations necessary
                                                                                                      Specifications according to drawing
tool in the grinding machine           for helix angel, rotation position, unclamped
                                       length, long tooth detection etc.                              Grinding from the solid block
                                       Only detection of the unclamped length
                                       necessary
                                       Resetting the open-face or cutting face without
                                       influencing the tool function




theless, the conditions for manufactur-                                                                  AN INCREASE IN CUSTOMER NUMBERS OFFERS
                                                   SIZE CLASSIFICATIONS OF GERMAN TOOL
                                                                                                           BETTER SECURITY IN TIMES OF ECONOMIC
ing and sharpening a tool are very dif-                    GRINDING COMPANIES
                                                                                                                       FLUCTUATIONS
ferent (see table).                                                      over 15 staff
                                                                             5%                          Sales /business        Logistic /accountancy
                                                        6 to 15 staff               1-man-opera-
                                                                                                               risk         expenditure and ancillary costs
   React fl exibly                                           27%                         tions
                                                                                         7%
The conditions and fi elds of activity
outlined above thus presuppose fl ex-                             2 to 5 staff
ibility in every respect. A business can                             61%
                                                                                                                    Number of customers
only be regarded as fl exible if
   it can handle differing technical          Well prepared: Tool grinders are mainly small           Reassuring: If a company has plenty of customers,
   enquiries on types of tools                companies with between two and five employees           there is less risk that business will suddenly collapse

   it is quick to react to customer
   enquiries
   in addition to sharpening tools, it        also improves fl exibility and enables crisis situations to be overcome more
   manufactures special tools                 easily. Grinding shops are an ideal size for this. They are generally small com-
   it can adjust its tool grinding            panies with an average of fi ve employees. A good quarter of them have between
   machines quickly to perform new            six and fi fteen staff. If a company has a large number of customers, naturally
   tasks                                      expenditure on sales and distribution work, logistics and therefore also for ac-
   is a master of grinding technology         counting rises. But the risk that turnover is suddenly going to plunge is consid-
   it can handle large production runs,       erably less. Well prepared, the
   and in particular small runs               companies which have provided                             ABOUT THE SPEAKER
                                              for conditions like those men-
For this it will require a large range of     tioned above will be able to handle
parts, short processing and delivery          the diffi cult economic situation.                    Prof. Wilfried Saxler is
times, improved staff productivity,           And any company which has so                         Managing Director of the
shorter idle times and a suitably adjust-     far not faced this subject now has                   Fachverband Deutscher
able level of automation.                     the opportunity to do so. Make                       Präzisions-Werkzeug-
                                                                                                   schleifer (German
All these criteria can only be achieved       your company fi t for the next eco-
                                                                                                   Precision Tool-grinders
with highly-qualifi ed personnel. Coop-        nomic boom – now. Because it’s
                                                                                                   Trade Association)
eration with other grinding companies         on its way...!




                                                                                                                                 MOTION 01/09             55
MARKETS & TRENDS




L e c t u r e I V-2 | M a y 8 , 2 0 0 9 | 10 .15


Many axes ensure success
Without multi-axis precision grinding machines there would be no modern high-performance
tools. MAPAL Dr. Kress KG is relying on this technological advantage.
By Dr Dieter Kress




N      ew, specially developed tools are
       often an important influence on the
success of a product because high-                                  which in turn results in effi cient manufacture of high accuracies whilst maintain-
performance tools help to transform                                 ing complex geometries.
machine effi ciency into high-quality
products. Grinding in particular plays a                                 Innovative high-performance drills
central role in the efficient manufacture                            Among the machining processes drilling is an important one because of its 40-per-
of innovative tools. Highest precision                              cent share of production time. In addition, solid drilling when processing pilot holes
– reliable and guaranteed to be repro-                              as a first process step is a determining factor in the achievable final quality. Con-
ducible – is virtually a basic require-                             sequently, innovative high-performance drills like the MAPAL MEGA Quadro-Drill
ment. The multi-axis design of the                                  or the MEGA-Deep-Drill have to guarantee high cutting values and have to provide
grinding machine furthermore ensures                                excellent results for roundness, straightness and diameter tolerance. That is why
the complete machining of high-per-                                 MAPAL is using modern multi-axis grinding machines with the appropriate software
formance tools in a single clamping,                                in its production processes. Only these machines are capable of processing the
                                                                                                                         specific geometries which are
                                                                                                                         responsible for chip formation
                                                                                                                         and cutting behavior of the drill
                                                                                                                         in a single clamping.
     MAPAL GIGA-Drill
     4 cutting edges for twice the feed rate
                                                                                                                         Apart from the margins which
                                                                                                                         are situated directly behind the
                                                                                                                         cutting edges, the MEGA Quad-
                                                                                                                         ro-Drill and the MEGA Deep
                                                                                                                         Drill have two additional guid-
                                                            MAPAL MEGA Quadro-Drill                                      ing margins which have con-
                                                            4 margins for better drilling quality                        stant contact with the wall of the
                                                                                                                         hole created while drilling. As a
                                                                                                                         result, roundness and straight-
                                                                           MAPAL MEGA Drill-Reamer                       ness of the hole produced are
                                                                           Drilling and reaming – one operation
                                                                                                                         considerably improved. The
                                                                                                                         specific geometry also opti-
                                                                                                                         mizes self-centering and brings
                                                                                                                         advantages when exiting drill
                                  MAPAL MEGA Deep-Drill
                                   Deep hole drilling up to 30×D                                                         holes at an angle. Due to the ad-
                                                                                                                         ditional support, the drill oper-
                                                                                                                         ates very quietly even with in-
                                                                                                                         creased cutting rates for steel
MAPAL high-performance drilling tools                                                                                    and cast materials. The deep-




56         MOTION 01/09
View of the MAPAL production facility: Multi-axis grinding technology for high-performance tools   Utmost precision: MAPAL high-performance drilling tools




hole drill has specific flute geometries                     quire around 20 per cent less torque than conventional twist drills with feed rates
and flute angles which provide good chip                    remaining the same. This means that the cutting speeds for cutting steel with up
clearance. Chips roll up tightly without                   to 200 m/min can be doubled with tool life travel remaining the same.
jamming and are removed safely even
from great drilling depths thanks to high-                     Modern reamers
ly polished surfaces.                                      Modern multi-flute reamers significantly reduce processing times for precision
The MAPAL MEGA drill-reamer com-                           drilling through high cutting speeds and very high feed rates. MAPAL sets new
bines drilling and reaming in a single                     standards in this area with its high-performance reamers. In order to guarantee
operation. The process combines dou-                       utmost precision in the μm range on all levels of the high-performance reamers,
ble-edged drill geometry with up to six                    the complete cutting geometry including all angles of the entire tool has to be
reaming margins for finish machining                        finished in one clamping following the cylindrical grinding process. Only multi-
the bore. The reaming margins protrude                     axis grinders with measuring systems and in-process dressing facilities can solve
radially by a few hundredths of a mil-                     this task efficiently. The same applies to PcBN reamers or cutters employed in
limeter above the drilling margins, re-                    machining cast materials or in hard machining. When grinding PcBN, oscillating
sulting in a defined reaming allowance.                     axes as well as compensation of wheel wear should be preset, in order to avoid
In contrast, the drilling margins are in                   clogging and scoring of the grinding wheels.
front of the reaming margins along the                     The new MAPAL reamers are equipped with PcBN cutting edges even in the di-
axis. Universally designed for use with                    ameter ranges of less than 6 millimeters. In this instance, PcBN is applied to the
steel, cast iron and aluminum, the MEGA                    front face and reproduc-
drill-reamer has an excellent self-center-                 es the entire cutting ge-
                                                                                                           ABOUT THE SPEAKER
ing ability and is an extremely efficient                   ometry, resulting in big
tool for pinhole drilling.                                 advantages of tool life
The latest development in MAPAL’s                          compared with conven-
solid carbide range is the MEGA Speed                      tional carbide reamers.                   Dr Dieter Kress is managing
drill. With its innovative face geometry,                  When hard machining a                     director of MAPAL Dr. Kress
it guarantees safe chip control, reduced                   hole with Ø 2.4 H7,                       KG. The company specializes
feed force and excellent self-centering                    MAPAL managed to in-                      in precision tools for metal
ability. As the guidance lands are no                      crease the output of a                    working; it is the headquar-
                                                                                                     ters of the MAPAL group
longer arranged on opposite sides, the                     carbide reamer from
                                                                                                     which employs more than
drill can no longer get jammed in the                      around 50 holes to over
                                                                                                     3,000 staff in 20 different
hole. Measurements show that due to                        1,300 holes with the                      countries
reduced friction MEGA Speed-Drills re-                     PcBN reamer.




                                                                                                                                               MOTION 01/09   57
MARKETS & TRENDS




L e c t u r e I V- 3 | M a y 8 , 2 0 0 9 | 11. 0 0


More power for microchip removal
The Institute for Machine Tools and Factory Management (IWF) at the TU Berlin exam-
ined characteristic phenomena of microchip removal with the aim of developing new
potentials for micro end milling cutters.
By Christoph Hübert




I   n micro milling, cutting edge round-
    ing is of similar size to the chip thick-
ness. Therefore, variations of cutting
edge rounding due to geometric de-                         milling tool ‘ploughs’ across the workpiece and reduces its surface quality. At
viation of the tool or the coating affect                  the Institute of Machine Tools and Factory Management (IWF) at the Technical
the process results more than in mac-                      University Berlin, these characteristic phenomena have produced several ap-
roscopic chip removal.                                     proaches for developing new potentials for micro chip removal.
Micro milling tools are fl exible due to
their small shank diameter. They warp                          Tool geometry
elastically during the process resulting                   Macro-range tools cannot be scaled down randomly into the micro range (tool
in erratic variations in chip thickness                    diameter < three millimeters). Geometric scaling produces unfavorable chip
which can lead to premature tool fail-                     formation mechanisms, resulting in an increase in process forces which in turn
ure if exposed to extreme stress. If the                   leads to premature tool wear. A wide range of tools from earlier micro end mill-
minimum chip thickness is undercut,                        ing cutters are not involved in chip formation. Furthermore, these tools show
neither shear plane formation nor chip                     a noticeable discrepancy between the effective tool length which has been
removal takes place; instead, plastic                      prepared with cutting edges and the axial depth of cut.
strain of the workpiece occurs. The                        New approaches in tool construction were able to eliminate these weak points.




                                        Tool 6-I
                                        z =3
                                        ap = 0,1 mm


                                                                                                                 Area of most common
                                                                                                                 tool failure


                                                                                                                 Area where mainly
                                                                                                                 frictional force is
                                                                                                                 effective

                                                                                                                 Zone where the stock removal
       500 μm                                                                                                    process takes place




Not involved in chip formation: Subdivision of the cutting area of traditional peripheral face milling cutters




58       MOTION 01/09
                                                                                                               at their disposal as well as the
                                                                                                               HELICHECK PLUS measuring sys-
                                                                                                               tem developed by WALTER which
                                                                                                               includes high-resolution cutting
                                                                                                               edge measuring sensors. The
                                                                                                               measurement of process force is
                                                                                                               an established and significant pa-
                                                                                                               rameter in the characterization of
                                                                                                               process behavior for procedures
                                                                                                               involving the geometrically unde-
                      Overall view                      Overall view                    Overall view
                                                                                                               fined cutting edge. The IWF uti-
                                                                                                               lizes the evaluation of internal
                                                                                                               drive signals of linear direct drives
                                                                                                               of the main thrust axes in order to
                                                                                                               maintain a database for the ef-
                                                                                                               fects of varying process param-
                                                                                                               eters and grinding tool specifica-
                  Detail: fl ute base               Detail: fl ute base               Detail: fl ute base         tions for typical tool grinding
                                                                                                               operations, in spite of existing
                                                                                                               limitations of data collection.
                                                                                                               Apart from the geometric charac-
                                                                                                               teristics, the process parameters
                                                                                                               of the grinding operation influence
                                                                                                               the rigidity of the micro tools and
                                                                                                               also, indirectly, the process reliab-
Reference structures with varying machining results: Hardened powder metallurgy steel (1.2379, 54 HRC)
and brass (CuZn39Pb3) have proved to be a suitable sample material. Fluted microstructures for deep            ility of the chip removal process.
milling and simple surfaces for the finishing process are used as reference structures
                                                                                                               The IWF investigated the quantifi -
                                                                                                               cation of this relationship. First,
                                                                                                               the effect of cylindrical grinding of
Parameterization of the tool geometry,                  carbide on the rigidity was analyzed. With micro tools, the machining of the
for example, enables automatic gen-                     diameter takes up most of the chip volume and the machining time at the cutting
eration of different geometry charac-                   edge and the transaction piece. Secondly, the effect of the cutting edge on the
teristics and the use of the finite ele-                rigidity of solid carbide tools was studied. The grinding operation determines
ments method for optimizing tools                       the edge-holding property and the rigidity of the tool through shape and qual-
according to demand. This makes the                     ity of the cutting edge and the underlying edge.
manufacture of milling tools with vary-
ing diameters and geometric charac-                        Use of micro cutting tools
teristics much simpler as the geomet-                   Currently, the IWF is studying the high-precision milling process in terms of
ric data can be entered directly into                   its effects on the structure of machine tools. Apart from a better understand-
the machine tool used for manufac-                      ing of the process /machine tool behavior, the objectives are the development
ture. Workpiece-dependent optimiza-                     and application of a forecast model for predicting these interactions and to
tion can now be carried out quickly                     establish a basis for:
and simply by varying the geometric                                                                          ABOUT THE SPEAKER
characteristics.                                           manufacturing microstructures
                                                           while observing tight
   Manufacture                                             tolerances and high surface                   Christoph Hübert is
The manufacture of solid carbide                           requirements and                              chief engineer at the
shank tools with diameters < three mil-                    guidelines for design and                     Institute for Machine
                                                                                                         Tools and Factory
limeters requires state-of-the-art ma-                     confi guration of the
                                                                                                         Management at the
chine technology for both tool grin-                       machine tool structure in
                                                                                                         Technical University
ding and tool measuring. The IWF has                       terms of optimization of                      Berlin
a Schütte 5-axis tool grinding center                      design and topology




                                                                                                                                 MOTION 01/09     59
MARKETS & TRENDS




L e c t u r e I V- 4 | M a y 8 , 2 0 0 9 | 11. 4 5


Metrology ensures profitability
Tight tolerances and improved accuracy in tool manufacture: Fully automated precision
metrology for the setting and monitoring of grinding machines and processes that is located
close to production improves precision and productivity.
By Oliver Wenke




T    hese days, reducing costs and in-
     creasing productivity is part of the
daily grind of manufacturing. To stay
competitive, tool production processes               ticularly for sensitive materials or very small dimensions. High-specification measu-
must continually overcome new chal-                  ring devices, such as the HELICHECK series of measuring machines from WALTER,
lenges where quality, versatility and                work quickly, are non-destructive and have uniformly high reproducibility with no
costs are concerned. Increased costs can             operator intervention. All the relevant tool parameters can be measured. Optical
only rarely be passed on to the custom-              measurement permits the extremely rapid, almost simultaneous, recording of a
er in the form of higher prices. Costs can           very large number of measuring points. Special measuring and evaluation pro-
only be reduced by continually optimiz-              cesses even allow measurements to be recorded over 360 degrees. They thus
ing production and increasing productiv-             record the actual shell profile of the workpiece and transmit the measurements to
ity. For innovative toolmakers and                   the process control, which makes appropriate corrections to the subsequent ma-
regrinders, this means very greatly                  chining process where necessary. This reduces scrap and minimizes the time spent
shortened cycles for new products or                 on traditional final inspection. Optical measurement is supported by powerful im-
services. This process can be success-               age processing and an easily operated measurement control system. Special edge
fully mastered with smooth coordination              detection processes, together with optimized illumination and image enhancement
of the experience of skilled tool develop-           software (see Figure 1, right) mean that even high-gloss polished surfaces, coat-
ers with the most up-to date manufactur-             ings or matt surfaces can be measured without difficulty.
ing technology and suitable metrology.
Contactless optical measuring tech-                    The ‘Closed Loop’ solution
niques play an important part here, par-             Absolute dimensional accuracy is critical for the performance of a shaping tool
                                                     and the result that it produces (see image left). The very tight workpiece tolerance,
                                                     sometimes less than +/- 3 μm, requires production and inspection processes to be
                                                                   precisely matched. In the case of the HELICHECK, the measurement
                                                                            program is based on the grinding program and can be pre-
                                                                                pared offline in advance. This saves the need for time-
                                                                                  consuming programming. Automatic correction is done
                                                                                   by DXF comparison of the theoretical and actual con-
                                                                                   tours. The corrections are calculated automatically
                                                                                  and adopted by the grinding machine. This results in
                                                                                 ‘good’ tools within the required tolerance and a stable
                                                                              production process. Given a suitable automation solution
                                                         such as a loading robot, this can be a completely unattended process. In this

Absolute dimensional accuracy: Crucial for the
                                                     way, tight tolerances can be reliably and cost-effectively kept under control. With
performance of a shaping tool and its results        an optical solution, a virtually unlimited variety of objects can be measured. Even




60       MOTION 01/09
[1]




[2]                                                                                 [3]
Advances: [1] Before-and-after results of the HELICHECK image enhancement system [2] Using optimally measured wheel sets on the HELICHECK, the fi rst tool is
usually already within the standard tolerance [3] The cutting edge rounding sensor enables accurate measurement of surface and contour cutting edge roundness
on metal-removing tools with μm precision




shafts and diamond dressing rolls can                 cess. The size of the radii and the resulting sensitivity of the cutting edge require
be measured without the need for ad-                  special measuring procedures. The development of the cutting edge rounding
ditional setting-up time. The optional                sensor (see Figure 3 above) opens up the possibility of accurately measuring μm-
lighting table extends the potential ap-              fine face and contour cutting edge roundness on metal removing tools. This new
plications to the measurement of non-                 option can be used to determine the entire microgeometry of a cutting edge and
rotationally symmetrical forms such as                all the other profiles on microcomponents. The combination of a number of cam-
profile sheets or indexable inserts. With              eras simplifies orientation on the tool and thus contributes to accurate, compre-
standard tools too, the measure-grind-                hensible and reproducible determination of the measuring point. This is also pos-
measure control circuit has a beneficial               sible even if the tool has been unclamped in the meantime. There is no need for
effect on tool optimization. It contributes           time-consuming manual pre-positioning. The measuring process lasts less than a
to improvements in cutting behavior,                  minute, with the actual measuring time being a mere 15 to 20 seconds. The rest of
tool performance and tool life.                       the time is needed for the sensor to approach the component being measured. The
                                                      relationship with the other sensors ensures that measurements are absolute. In
   Faster and more economical                         addition to the radius, width and form of the cutting edge the system also deter-
If the geometry of the cutting edges is               mines its exact position on the tool.
optimized, the effect on machining char-
acteristics is highly beneficial. Excellent               Summary
edge stability, fewer fractures and long-             The WALTER HELICHECK is a com-
er tool life make for improved machining              plete system for all measuring tasks.                   ABOUT THE SPEAKER
quality and quiet running at high metal               Tool grinders benefi t from cost-
removal rates. The trend is towards                   effi ciently monitored production
lesser rounding of edges and some                     and can therefore react quickly and               Oliver Wenke is Head
asymmetrical radii. Another reason why                reliably to their customers’ wishes.              of the Measuring
the cutting edge radius was previously                For both one-person businesses                    Technology Develop-
                                                                                                        ment Center at Walter
generated in a rather random way was                  and large companies, the potential
                                                                                                        Maschinenbau GmbH
because it was difficult to measure the                savings are enormous and continue
                                                                                                        in Garbsen near
result precisely and draw conclusions                 to rise as the variety of tools in-
                                                                                                        Hanover, Germany
that could be incorporated into the pro-              creases.




                                                                                                                                    MOTION 01/09            61
MARKETS & TRENDS




L e c t u r e V-1 | M a y 8 , 2 0 0 9 | 14 . 0 0


Process optimization using simulation
Abrasive tool materials: Simulation models at the Swiss Federal Institute of Technology (ETH)
in Zurich enable the number of active grains, their cutting surfaces, and the resulting forces, rugosity
and service life to be defined.
By Prof. Konrad Wegener




T     he use of empirical methods with
      high-performance cutting tools is
not just time-consuming and expen-
sive, it is complicated by the fact that           tolerance. The microgeometry is defined by the geometry of the grains and their
many infl uencing factors come into                 arrangement. In the case of engineered grinding tools, where it is assumed that
play simultaneously, making it very                the grains are in defined positions, their actual locations are defined by the un-
diffi cult to assign the observed effects           certainty of the positioning process. The coolant and the chips occupy the clear
and derive rules for them. In contrast,            spaces between the grains. The stochastic tool model is fully defined in three
analytical and digital tools and process
models can provide scientifi cally based
findings.


     Modeling                                                    KINEMATIC MODEL                            STOCHASTIC TOOL MODEL
                                                                    Grinding speed                            Grain morphology
The simulation model for single-layer                               Tool advance speed                        Grain pattern
abrasive coatings of diamond or CBN                                 Workpiece speed                           Pattern accuracy
                                                                                                              Size and orientation of grains
grains consists of a stochastic model
of the tool, a kinematic model of the                            Cutting data                                      Tool geometry
process, a material removal model and
                                                                                MATERIAL REMOVAL MODEL
a failure and wear model. It enables the                                                                                           Change in tool
                                                                                  Tool-workpiece interaction
                                                                                                                                   topologyWear
number of active grains, their cutting                                            Rigidities
                                                                                                                                      Failure
                                                                                  Plasticity
surfaces, and the resulting forces, ru-
gosity and service life to be defi ned                                                                                         WEAR MODEL
                                                                                         Proportion of active grains            Blunting of grains
and the probability of their survival                                                    Workpiece rugosity, chip space         Grain fracture
                                                                                         Cutting area of grains                 Jagged grains
under given conditions of use to be
                                                                                                                                Clogging of interstices
evaluated. It is based on a simplifi ed
                                                              MODEL OF COOLING             MODEL OF INDIVIDUAL GRAIN
description of elementary events, ob-                         SYSTEM                         Kienzle model
tained from tests on individual grains                          Pressure, quantity           Clamping forces
                                                                Coolant                      Hardness
and simplifi ed for the purposes of nu-
merical treatment.                                                     Coolant flow             Forces on the grains

                                                                                THERMAL MODEL
     Stochastic model                                                             Temperature rise
The modeling for the tool incorporates                                            Thermal conduction
its macrogeometric and microgeomet-
                                                                             Tool/workpiece temperature
ric properties. The macrogeometry is
described using the nominal geometry
of the grinding tool and the associated            Scientifically based: A view of the simulation model




62       MOTION 01/09
                                                                                    er hand there must be suffi cient clear space for the
                  THEORETICAL CRYSTAL MORPHOLOGY OF                                 chip that is removed to collect temporarily in the tool.
                          SYNTHETIC DIAMOND
                                                                                    If overload occurs a greater or lesser proportion of
                                 Cube/octahedron
                                                                                    the grain can break off, or even be completely torn
                                                                                    out of the bonding material. This is taken into account
                                                                                    in the model by load thresholds for the various types
                                                                                    of change in grain geometry. Allowance can thus be
                                                                                    made for macroscopic effects such as clogging, scor-
                                           Simulated grain morphology               ing and blunting of the grinding tool.

            Diamond PDA989
                                                                                      Behavior of individual grains
             THEORETICAL CRYSTAL MORPHOLOGY OF CBN                                  In practical cutting with individual grains it is possible

                              Octahedron/tetrahedron
                                                                                    to determine the specific cutting force according to
                                                                                    Kienzle from the correlation of the measured process
                                                                                    forces and the scoring that is formed in the workpiece.
                                                                                    The orientation of the grain with respect to the direction
                                                                                    of cut must be noted. The load threshold at which the
                                                                                    grain fractures can be found by increasing the depth of
                                          Simulated grain morphology                penetration into the workpiece.
                                                                                    Practical grinding tests have shown that an increase
               CBN ABN800
                                                                                    in the specifi c metal removal rate has an effect on the
Idealized geometry: Grain morphology of diamond and CBN                             rugosity of the workpiece. This is because a higher
                                                                                    load on the active individual grains changes the sur-
                                                                                    face topology of the grinding wheel, depending on
                                                                                    the grain fracture behavior, and therefore changes
cylindrical coordinates by the following              the distribution of active grains. Appropriate consideration of grain wear there-
parameters, arranged in order of prob-                fore has a critical influence on the quality of the rugosity that is calculated in
ability: grain size, grain shape, grain               the simulation. At high cutting volumes in particular, the difference between
orientation and positional deviations.                the numerical simulation and the measurement is greater when there is no wear
                                                      criterion. In the simulation model used, the active cutting surface of the grain
   Material removal                                   is used as the wear criterion. The critical cutting area at which the grain profile
The material removal model reduces                    changes is correct when the measured number of fractured grains on the tool
the complex elastoplastic processes                   and the workpiece rugosity are the same as the calculated values.
on the grain to the geometric interac-                The change in grinding wheel topology can also be seen in the distribution of
tion of the abrasive grains with the                  the cutting surfaces of the grains. On tools that have not been ground there are
workpiece. This enables the new work-                 a few grains that have a large cutting area and these have a considerable influ-
piece surface that is created and its                 ence on rugosity.
rugosity to be determined in the mate-
rial removal simulation. Using Kien-                      Summary
zle’s cutting force model we obtain the                   The model enables
                                                                                           ABOUT THE SPEAKER
force acting on each individual grain                     process and tool data
and, by summation of this for all the                     to be harmonized.
                                                                                       Prof. Konrad Wegener is
active grains, the process force acting                   The interaction of
                                                                                       CEO of the Swiss
on the workpiece.                                         different simple models      company Inspire AG für
                                                          and parameter studies        mechatronische Produk-
   Failure and wear                                       improves our under-          tionssysteme und
When designing or selecting a grinding                    standing of the process      Fertigungstechnik and
tool the cutting and movement kine-                       The effects of separate      also Head of the Institute
matics of the machining process must                      parameters on complex        of Machine Tools and
                                                                                       Manufacturing at the
be taken into account. On the one hand,                   processes can be
                                                                                       Swiss Federal Institute of
the individual grains must not be me-                     unambiguously
                                                                                       Technology in Zurich
chanically overloaded, but on the oth-                    investigated




                                                                                                                        MOTION 01/09        63
MARKETS & TRENDS




L e c t u r e V-2 | M a y 8 , 2 0 0 9 | 14 . 4 5


Economic hard finishing
Shorter product cycles, niche products and site relocations require a high degree of standardiza-
tion in plant procurement and plant reusability. This needs to be taken into account in the hard
finishing of precision components.
By Dr Frank Fiebelkorn




O     ptimization of future fi nishing
      processes requires an overall view
of the appropriate machine concepts
plus the ability to use advanced manu-
facturing technology. To achieve the
ideal synthesis of high productivity and
versatility, two strategies stand out:              Vast potential: The
                                                    prototype system for EDM
complete machining and combined                     dressing
processing.
Using a modular machine structure it
is possible to pursue a consistent pol-
icy of complete machining. Often, it is
only by clamping the workpiece once
and for all that the required quality pa-
rameters in respect of surface finish
and accuracy of form and position can
be guaranteed. It is the only way to re-
duce throughput times. The machine
systems used in this way bring the func-
tions of a number of special machines
together on just one platform. The most
up-to-date programming and control
modules also contribute to the ability
to machine even non-round profiles or
threads completely without re-clamp-
ing the workpiece (see Figure 1).


     Effi cient software modules
The comprehensive StuderGRIND pro-
gramming system is an example of this
type of modern grinding software. Its
modules support the machine operator
in a process-oriented manner and con-
sequently minimize the work prepara-               quired, for example contour editors designed for the workshop, interfaces for
tion of component manufacture. The                 importing contour data, simulations or the store of in-house knowledge and
operator can use the functions as re-              skills. In addition to all this, the overall control system guarantees the integration




64       MOTION 01/09
[1]                                                      [2]                                                      [3]
[1] Using specific grinding processes to increase productivity [2] Grain projection after dressing by EDM [3] Combined processes lead to economies in production




of the operator interface of external                       Combined processes
modules such as sensor system pack-                     Another strategy for increasing productivity is to combine hard finishing pro-
ages, measurement control or handling                   cesses on a single machine. This enables the grinding process to meet the high
systems from third-party suppliers. The                 accuracy specifi cations for close tolerance with guaranteed process capability
signifi cance of these person-machine                    and highly specifi ed surface finishes. Hard turning scores highly because of the
interfaces for programming, setting up                  great versatility of its geometrically defined cutting edge. The combination of
and managing finish machining pro-                       the two processes offers the ability to select the most effi cient machining tech-
cesses is increasing all the time.                      nique to suit the task in hand.
                                                        Combined hard turning and grinding has now established a place for itself for
   Productive carbide                                   the manufacture of gears in the chuck, for universal use and for the series
   machining                                            manufacture of precision components that need to be machined between cen-
Alongside the various traditional meth-                 ters or in a chuck.
ods, the technology of high speed grin-
ding for carbides and ceramic with                          Minimizing changeover times
changing form elements on the work-                     The potential user can therefore choose between a number of ideal process
piece has distinct productivity benefi ts.               strategies for machining precision components. In each case, minimizing the
The diamond grinding wheels that are                    time spent changing over is a particular feature, particularly when batch sizes
used for this purpose generally have                    are small. Toolholders, for instance, can be machined between driven centers
ceramic or metal-based bonds. The dis-                  (see photo 3). It is therefore possible to start by turning both sides of the whole
advantage to be set against their high                  contour including the tool changer fl ange, and then, without re-clamping, ac-
wear resistance, however, is that of                    curately grinding the cones and fl at mountings with great process reliability
dressing. It is very time-consuming and                 using measurement control systems. STUDER has been able to optimize the
expensive to profile and sharpen these                   internal machining of workpiece-specifi c toolholder bores equally well with
tools, particularly if they have special                other types of holder with HSK interfaces. The process-specifi c steps of pre-
contour lines on the abrasive coating.                  drilling and fi nish grinding of the bore have led to excellent bore quality param-
In cooperation with project partners,                   eters with deviations of 0.3 μm for roundness, 0.2 μm for straightness, 0.6 μm
STUDER has therefore initiated a re-                    for cylindricity and a mere 1.5 μm
search project to develop a new profil-                  for dimensional accuracy.                                   ABOUT THE SPEAKER
ing and sharpening process using spark                  The philosophy outlined here of
erosion (EDM – Electro Discharge Ma-                    combined hard finishing (grinding
chining, see left-hand photo). Initial                  and turning) expands the decision                     Dr Frank Fiebelkorn is
studies and process tests have shown                    matrix of production planners for                     Head of Product
positive potential for profiling ability                 future production processes. It not                   Development,
and the creation of suffi cient grain pro-               only enables hard turning to be                       Research and
                                                                                                              Technology at Fritz
jection for subsequent grinding (see                    combined with grinding; it includes
                                                                                                              Studer AG in Thun,
photo 2). Further studies will follow,                  milling with driven tools, hard
                                                                                                              Switzerland
with a view to industrial application.                  reaming and honing.




                                                                                                                                           MOTION 01/09            65
MARKETS & TRENDS




L e c t u r e V- 3 | M a y 8 , 2 0 0 9 | 15 . 3 0


The final polish
In precision grinding of hard and brittle high-performance ceramics under production
conditions, everything depends on the design being suitable for ceramics.
By Dr Carsten Russner




H     igh-performance ceramic material
      has many outstanding properties:
it is very hard and very light, and is
highly resistant to wear, pressure and
heat. Consequently, this material can
be used in conditions where steel or
plastic would not work. In manufactur-
ing technical ceramics it is in particular
finishing, using product-specifi c grind-
ing and polishing processes, which
represents a decisive time and cost fac-
tor. Precision production grinding will
be described using four different grin-
ding processes:
                                                             50 per cent less production time: Using a three-stage process in angular plunge-cut grinding, the
                                                             CeramTec specialists avoid inaccuracies
     Double face grinding of transverse
     sides with planetary kinematics
     Angular plunge-cut grinding with
     centerless technology                            Double face grinding of transverse sides
     Centerless grinding of pump rollers            In double face grinding of transverse sides, the infeed movement is made up of
     Cylindrical grinding of ceramic                two components performed by different machine elements: the grinding speed
     materials                                                 and infeed speed running lengthways to the workpiece. The overlap-
                                                                         ping of the infeed movements is responsible for the good
                                                                             grinding results and evenness of tool loading. Most impor-
                                                                             tant input parameters in double face grinding of transverse
                                                                             sides with planetary kinematics are the grinding speed and
                                                                             the grinding normal force in an axial direction. An increase
                                                                             in the average grinding speed improves workpiece depth
                                                                              pattern and surface, while an increase in grinding normal
                                                                              force in an axial direction increases the depth of grain cut.
                                                                              This has a negative effect on the surface quality. A decisive
                                                                             part was played by selection of a suitable lubricant. This
                                                                           made possible an increase in the metal removal rate by a
                                                                         factor of three. Including automatic feeding and discharge of
                                                                       the workpieces, there was an improvement in productivity over-
Between centers: Grinding media being
ground on the KRONOS S                                               all of 200 per cent, while all the required tolerances for mass




66       MOTION 01/09
production were achieved. The trend is
away from grinding wheels with ex-
treme diameters in excess of 1,200 mm
and towards higher grinding speeds.


  Angular plunge-cut grinding
Grinding media of Si3N4 are ground on
KRONOS S machines from MIKROSA.
On these machines, the previous              [1]                                                      [2]
processing between centers can be sub-
stantially reduced. The grinding tool is
a diamond grinding wheel, while the
dressing roll is a newly-developed dia-
mond form roll from Messrs. Saint-
Gobain Winter. Neither of these has any
problem in maintaining the required tol-
erances. It is a major challenge however
to profile the grinding wheel: wear of the
dressing roll cannot be measured. This
means that the CNC program miscalcu-
lates the corrections. This then results
                                             [3]
in inaccuracies, and to avoid these, the
                                             The CeramTec product variety: [1] Seals made of various high-performance ceramics [2] Wear parts, ground
specialists from CeramTec AG divided
                                             with a diamond grinding wheel [3] Various special components
the process up into three stages:


  Pregrinding the curved surface
  Grinding the face and the
  curved surface                                Cylindrical grinding
  Finishing grinding of the                  CeramTec today grinds ceramic insulators for the CFC zirconium oxide high-
  curved surface                             performance brake in an HSG process on STUDER S32 machines at a grinding
                                             speed of 125 m/s.
In this way, not only was a cmk-factor       Here too, ceramic-bonded grinding wheels are used. The stock removal rate is
of 3.86 achieved for the curved surface,     over eight mm³/mms and the G-ratio is better than 1,000. The tolerances achieved
process time was reduced by 50 per           in the diameter in ceramic mass production are less than six μm.
cent as well.
                                                Hard grinding costs and accuracies
  Centerless grinding                         In general, the saying ‘the more accurate, the more costly’ does not apply. It
Extreme demands are made of pump             depends much more on a design suitable for ceramics, and the opportunities
rolls in respect of their stress gradient.   these designs offer for hard grinding. Thus centerless plunge-cut grinding is to
The roll must fall logarithmically from      be preferred to grinding between centers as in this way an intricate stage of
the center to the faces by 1.7 μm in or-     workpiece clamping is dispensed with. Admittedly this is at the expense of the
der to avoid extreme peaks of stress. If     achievable tolerances, specially
it is required to achieve these gradients    in coaxial work. It may be as-
                                                                                                    ABOUT THE SPEAKER
in honing work, the preceding center-        sumed that fast automation con-
less grinding with ceramic-bonded dia-       cepts, higher grinding speeds
mond grinding wheels must lie within         and higher grinding normal forc-                Dr Carsten Russner
a range of ± 0.002 μm. These toleran-        es will increase productivity by                is Manager Innovation
ces can only be achieved by grinding         a factor of ten. In the manufac-                – Business Development in
in a clamp and the use of ceramic-bond-      ture of workpieces with toler-
                                                                                             the business sector
                                                                                             Systems Technology at
ed grinding wheels dressed in the ma-        ances in the μ range, new dress-
                                                                                             CeramTec AG with a focus
chine. Here, the dressing is of major        ing strategies will certainly play
                                                                                             on product development
importance.                                  a decisive role.




                                                                                                                              MOTION 01/09              67
                         Leading...
                                       ...results from
                          the perfect combination
                                of many factors




Gauging and                         Acoustic                            Grinding wheel                    If your targets are:
control for                         sensors for                         balancing                         To encrease productivity,
grinding machines                   grinders                            systems                           To reduce production costs,
                                                                                                          Then contact us!




Please visit our website where you will find more detailed information and your nearest Marposs office.


www.marposs.com                       www.marposs.de                      www.marposs.ch
L e c t u r e V- 4 | M a y 8 , 2 0 0 9 | 16 .15


The ideal grinding medium
When choosing the best possi-
ble grinding medium for a spe-
cific application there are many
parameters to be considered.
By Walter Graf




                                                    Ideal: The right
                                                    grinding medium
                                                    results in top product
                                                    quality


T    oday, users of grinding machines
     have a wide choice of abrasive ma-
terials at their disposal. Each of these –
whether aluminum oxide, sintered alumi-
num oxide, CBN or diamond – has a wide              Aluminum oxide
variety of variants. They all have their own      Aluminum oxide is made from melted bauxite, the basic material in the produc-
specific uses and the crucial problem is           tion of aluminum. It is characterized by its white color and in particular by its
selecting the ideal grinding medium for           hardness and splintering ability. The purity grade lies between 98.5 and 99.5 per
each task. Lot sizes, surface quality, fire        cent. In order to increase the tenacity of aluminum oxide, chromium oxide in
prevention and dressing tool wear play            quantities of 0.2 per cent (pink aluminum oxide) or up to 5 per cent (ruby red
an important part in this decision.               aluminum oxide) is added to the melt.


   Grinding media                                   Single crystal aluminum oxide
The following abrasive types are mainly           Single crystal aluminum oxide which is somewhat tougher and therefore splinters
used today:                                       differently to aluminum oxide is produced in a special process. Grinding wheels
    Aluminum oxide and single crystal             made from single crystal aluminum oxide can achieve a very long service life if
    aluminum oxide                                used in suitable applications. But the main use of single crystal aluminum oxide is
    Sintered aluminum oxide                       as support grain and filler grain in CBN grinding wheels.
    CBN (cubic boron nitriole)
                                                    Sintered aluminum oxide
These varieties of corundum are classed           In the early Nineties, a process was developed to manufacture the smallest pure
as conventional grinding media; they are          corundum grains with an average diameter of between 0.0002 and 0.0025 mil-
mainly used as a ceramic bond in preci-           limeters and to sinter them into blocks. The result was sintered aluminum oxide.
sion grinding operations.                         During a controlled sintering process only the grain boundaries of the nano-




                                                                                                                MOTION 01/09       69
MARKETS & TRENDS




sized grains are melted while the small                   amount of bond will allow higher
                                                                                                        Uncrushed           Spread of grain sizes
single grain remains as such. In theory,                  grinding performance. Sintered alu-
this results in one billion grinding par-                 minum oxide is primarily used in
                                                                                                                         Steel base
ticles with an average crystallite size                   high- performance creep feed grin-          [1]
of 0.0005 millimeter (0,5 μm). Sintered                   ding of diffi cult-to- grind materials
aluminum oxide is available in four types                 like Inconel. The disadvantage of ex-
with different characteristics and per-                   truded corundum is that dressing                                                  Crushed

formance potentials:                                      tool wear is particularly high.
                                                                                                        Spread of grain sizes
     Cubitron 321 (3M) for universal                        CBN
     applications                                         The superabrasive grinding medium
                                                                                                                          Steel base
     Cerpass 560 (Saint-Gobain) for                       CBN comes in many varieties. It is
     high grinding pressures                              available ceramically bonded, resin-
                                                                                                      [2]
     Cerpass DGE (Saint-Gobain) for                       bonded, galvanically bonded and
     flimsy, unstable workpieces                           metal bonded in monocrystalline or
     Cerpass TGE (Saint-Gobain) for                       microcrystalline versions, whereby
     creep feed grinding, for Inconel etc.                the monocrystalline version consists
                                                          of larger crystallites which break up
                                                                                                      3]
                                                          more coarsely with excellent, sharp        Established: [1 + 2] Crushing of galvanized CBN
                                                                                                     grinding wheel [3] Firm, medium and high toughness
                                                          cutting edges. Microcrystalline CBN        of CBN grains
                                                          behaves similar to sintered alumi-
                                                          num oxide. The crystallites are small-
                                                          er and only split under higher pressure. Today, the monocrystalline version is
                                                          predominant and ceramic and galvanic bonds have taken over.


                                                            Galvanically bonded CBN
                                                          Galvanically bonded CBN grinding wheels have a major advantage. They do not
                                                          require dressing, yet they achieve highly accurate profiles and surface qualities.
                                                          These results are guaranteed by the crushing process where the cutting edges
                                                          are fractured to size with a high-precision carbide roller. Regardless of bonding
                                                          variety or specifi cation, CBN grinding wheels should only be used on a high-
                                                          performance machine. Racing tires do not turn a medium sized vehicle into a
                                                          fast Formula One car.


Sintered aluminum oxide: Cerpass 560 (Saint-Gobain)       When choosing the right grinding medium the
for high grinding pressures and all grinding operations   following issues should be clarifi ed:
                                                          1. CBN: yes or no?
The blocky grain shape of Cerpass 560                     2. Is the machine powerful enough?
is particularly suited to grinding op-                    3. Does it have a rotating dresser? If not, is the use of galvanically bonded CBN
erations with high grinding pressures,                      grinding wheels to be considered?
such as pendulum surface grinding.                        4. Is the cutting speed above 35
Cerpass DGE with its tapered grain                          m/s? (High Q’w values can only             ABOUT THE SPEAKER
structure, on the other hand, is better                     be reached at ≥ 80 m/s.)
suited to grinding flimsy, unstable parts                  5. Is grinding oil an option? If yes,
and internal grinding where rigidity is                     does the machine have a
limited due to the grinding quills. Rod-                    CO2-fire extinguishing system?          Walter Graf is
shaped Cerpass TGE is in fact an ex-                                                               Chief Marketing
truded grain. This grain shape allows                     Ultimately, there is not one ideal       Officer of the
a very small amount of bond, as the                       abrasive but only the best possi-        Winterthur
                                                                                                   Technology Group
grain shape is building up a reinforced                   ble abrasive for each particular
                                                                                                   in Winterthur,
wheel structure. With a high concentra-                   grinding task and economic re-
                                                                                                   Switzerland
tion of sintered aluminum oxide a small                   quirement.




70       MOTION 01/09
CNC CONTROLS              DRIVE SYSTEMS                LASER SYSTEMS                        SERVICE




10 Years Production
0 Failures
100 % Availability
Maximum machine availability:
with CNCs from Fanuc GE
Our CNCs are the most reliable controls in the world:
because statistics have demonstrated that the first failure
may not happen till 10 years have passed. This will save
expensive services and reduce the TCO (Total Cost of
Ownership) to a minimum. Your benefit: highest reliability
for maximum availability.

Just one of our strengths.


Fanuc GE CNC UK Ltd. / 15 Basset Court - Loake Close   Fanuc GE CNC Europe S.A.
Grange Park / UK-Northampton NN4 5EZ                   Zone Industrielle / L-6468 Echternach
Tel.: (+44) 1604 7441 30 / Fax: (+44) 1604 7441 31     Tel.: (+352) 72 79 79 1 / Fax: (+352) 72 79 79 510
info.uk@fanucge.com / www.fanucge.co.uk                info@fanucge.com / www.fanucge.com
                          Blohm Jung GmbH                                       Studer Mikrosa GmbH
                          Kurt-A.-Körber-Chaussee 63–71                         Saarländer Straße 20
                          21033 Hamburg, Germany                                04179 Leipzig, Germany
                          Tel: +49-40-7250-02, fax: +49-40-7250-3287            Tel: +49-341-4971-0, fax: +49-341-4971-500
                          sales-hh@blohmjung.com, www.blohmjung.com             sales@mikrosa.com, www.mikrosa.com

                          Jahnstraße 80–82                                      Studer Schaudt GmbH
                          73037 Göppingen, Germany                              Hedelfinger Straße 137
                          Tel: +49-716-1612-0, fax: +49-716-1612-170            70329 Stuttgart, Germany
                          sales-gp@blohmjung.com, www.blohmjung.com             Tel: +49-711-4014-0, fax: +49-711-4014-290
                                                                                sales@schaudt.com, www.schaudt.com
                          Combitec AG
                          Lengnaustrasse 12, 2504 Biel, Switzerland             Fritz Studer AG
                          Tel: +41-32-344-0450, fax: +41-32-341-0671            3602 Thun, Switzerland
                          info@combitec.ch, www.combitec.ch                     Tel: +41-33-439-1111,
                                                                                fax: +41-33-439-1112
                          Ewag AG                                               info@studer.com,
                          Industriestrasse 4, 4554 Etziken, Switzerland         www.studer.com
                          Tel: +41-32-61331-31, fax: +41-32-61331-15
                          info@ewag.com, www.ewag.com                           Walter Maschinenbau GmbH
                                                                                Jopestraße 5
                          Mägerle AG Maschinenfabrik                            72072 Tübingen, Germany
                          Allmendstrasse 50, 8320 Fehraltorf, Switzerland       Tel: +49-7071-9393-0, fax: +49-7071-9393-695
                          Tel: +41-43-3556-600, fax: +41-43-3556-500            info@walter-machines.com,
                          sales@maegerle.com, www.maegerle.com                  www.walter-machines.com




                          Körber Schleifring Asia-Pacific PTE. Ltd.              United Grinding Technologies, Inc.
                          25 International Business Park                        5160 Lad Land Drive
                          #01-53/56 German Centre                               Fredericksburg, Virginia 22407, USA
                          Singapore 609916                                      Tel: +1-540-898-3700, fax: +1-540-898-2811
                          Tel: +65-6562-8101, fax: +65-6562-8102
                          michael.schmid@walter-machines.de                     United Grinding Technologies, Inc.
                                                                                510 Earl Boulevard
                          Körber Schleifring Machinery Shanghai Co. Ltd.        Miamisburg, Ohio 45342, USA
                          Beijing Branch Office                                  Tel: +1-937-859-1975, fax: +1-937-859-1115
                          Room 10-04, CITIC Bldg. 19, Jian Guo Men Wai Da Jie   ugt@grinding.com
                          Beijing 100004, China
                          Tel: +86-10-6595-9934, fax: +86-10-6500-6579          Körber Schleifring UK Ltd.
                          info@schleifring.cn                                   B13 Holly Farm Business Park, Honiley
                                                                                Kenilworth, Warwickshire, Great Britain
                          Schleifring Brasil Ltda.                              CV8 1NP
                          Av. XV de Agosto, 5.060                               Tel: +44-1926-4850-47, fax: +44-1926-4850-49
                          Sorocaba, Brazil, CEP: 18085-290                      neil.whittingham@walter-machines.de
                          Tel: +55-15-322457-26, fax: +55-15-322813-66          info.wg@walter-ag.com
                          vendas@schleifring.com.br
                                                                                Körber Schleifring
                          Körber Schleifring France                             Machinery (Shanghai) Co., Ltd.
                          2 bis, Avenue du Président François Mitterrand        No. 1128, Taishun Rd, Anting Town
                          91385 Chilly-Mazarin, Cedex, France                   Shanghai Jiading 201814, China
                          Tel: +33-1-697921-21, fax: +33-1-697921-10            Tel: +86-21-39587333, fax: +86-21-39587338
                          commercial@schleifring.fr                             info@schleifring.cn

Körber Schleifring GmbH   Körber Schleifring Italia Srl                         Schleifring Service AG
Nagelsweg 33–35           Via G. Garibaldi, 118                                 Thunstrasse 15
20097 Hamburg             22073 Fino Mornasco (CO), Italy                       3612 Thun, Switzerland
Germany                   Tel: +39-031-926-262, fax: +39-031-926-261            Tel: +41-33-439-1212, fax: +41-33-439-1514
Tel: +49-40-21107-03      info.it@walter-machines.com                           info@serviceag.net
Fax: +49-40-21107-13
                          Körber Schleifring GmbH – India Branch Office          Schleifring Service GmbH
info@schleifring.net
                          No. 99, Spencer Road, First Floor, Frazer Town        Hedelfinger Straße 137
www.schleifring.net       Bangalore 560 005, India                              70329 Stuttgart, Germany
                          Tel: +91-80-412504-25, fax: +91-80-55658-99           Tel: +49-711-4014-100, fax: +49-711-4014-207
                          sales@schleifring.in                                  info@servicegmbh.net

								
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