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									                                                Session 6
             WFO
        Technical Forum
             2003                Process control and visual inspection                 3.1



                Integration of peripheral functions – a way to more
                                    efficiency in die casting


                          Bernard Aschmann, Bühler Druckguss AG, Uzwil, Switzerland




Die casting on the one hand has new possibilities in new areas of application on the
other hand, however, the competition with other processes and materials is becom-
ing more intense. In this environment increasing attention has to be given in the fu-
ture to the economy of the die casting process. In connection with increase in pro-
ductivity the phrase „cycle time reduction“ is mentioned quite frequently. Cycle time
reduction certainly is a factor. Under the definition „more parts per unit of time, at bet-
ter quality and lower total cost“, however, additional extensive measures have to be
taken. Downtimes of the installation are a factor not to be underestimated that can
considerably reduce the productivity of an investment.
Downtimes today are mainly attributed to:
   ·     Setting
   ·     Problems with the die, the peripheral equipment, at the machine
   ·     Production optimization
   ·     Service and maintenance


Normally a new investment passes different phases .In order to achieve maximum
productivity the correct decisions and measures have to be taken first in all three
phases. Basis for the economical production of die-cast parts are the „Management
decisions“, i.e. the decisions regarding the process to be applied and the concept of
automation. Just as important in our view, is the technical support as well as the ser-
vice provided by the supplier during the operation of an installation and also the
know-how and early and permanent training of the foundry personnel in the areas of
technology, setting, programming, trouble shooting and elimination in electronics and
hydraulics. All these are factors that strongly influence the availability of an installa-
tion.



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                                          Session 6
            WFO
       Technical Forum
            2003             Process control and visual inspection                   3.2



It would be beyond the scope of this short paper to discuss all factors in detail.
Therefore I will limit my paper to the concept of automation, the integration and coor-
dination of the peripheral functions within a die casting cell.
If one wants to utilize the whole potential of a value added chain then considerable
attention has to be given to the inclusion of the peripheral equipment and the com-
munication of the peripheral functions amongst each other. The die casting cell has
to have high availability.


Die casting cell


The basic functions of a die casting cell are the machine, metal ladling, die sprayer
and extraction device. Traditionally all devices are supplied by different suppliers and
are then connected on site relatively loosely to each other via simple digital inter-
faces.
Modern technologies have enabled new linkages within the die casting cell.


Integral cell, one possible solution


Under integral cell we understand the full or partial integration of peripheral functions
into a control system. There are various possible solutions.
The first possible solution is the full integration of the peripheral equipment, i.e.
hardware and software as well as operation, programming and diagnosis (Man-
Machine Interface HMI) are combined in one control system. The advantage of this
solution is in the standardization of the hardware and software as well as in the cen-
tral, identical programming and operation of the complete installation.
The partial integration is done via bus systems, in particular via the well-known
Profibus-DP system. Control cabinets and hardware remain decentralized. Pro-
gramming, operation and diagnosis are carried out centrally.
The advantage of this solution is in the flexibility regarding the selection of the pe-
ripheral units as well as in the identical, central operation, programming and diagno-
sis.
What benefit can the user gain from integrated peripheral equipment?


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                                         Session 6
           WFO
      Technical Forum
           2003             Process control and visual inspection                         3.3




Project realization


The processing time of a project from order to delivery can be shortened, since there
is hardly any time required for the coordination with the different manufacturers of pe-
ripheral equipment. The peripheral equipment is specified and known and the com-
munication of the devices amongst each other has already been realized. A project
manager acting as a contact, who manages the complete installation, will considera-
bly reduce the time and effort involved at the customer during the projecting phase.


Commissioning


The commissioning time can be reduced since it is a plug ’n’ play solution. Only a
small crew of the installation supplier will be on site to carry out all necessary work.
Coordination efforts amongst different suppliers and the corresponding waiting times
will be a thing of the past.
Due to the identical operating philosophy of machine and peripheral equipment the
training expenditure for the personnel of the customer can be reduced. Part of the
training will take place during commissioning.


Operation


The big benefit of integrated solutions, however, results from the operation, starting
with the setting of the production . The production program can be read in for the en-
tire die casting cell with a data carrier at a central location. This will result in time sav-
ing because the programming at the individual control systems is no longer required
and thus the number of errors is reduced.
The operation of all devices takes place from a central control desk and central Man-
Machine Interface. This improves the overall control, saves time and reduces the
stress of the operating personnel. Resetting the complete installation to the initial po-
sition after a standstill can take place at a central operation element. The laborious
resetting of the individual devices will not be required anymore.


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                                         Session 6
           WFO
      Technical Forum
           2003            Process control and visual inspection                        3.4




Diagnosis


Downtimes today are a considerable cost factor. Analyses have shown that most
downtimes are caused by the die. Ranked second are faults from the peripheral
equipment, originating from the interaction of the different devices. It is often difficult,
however, to identify what caused the fault.
Integral solutions contain a central, universal diagnosis system with an identical
alarm system. This means that a fault in the installation can be quickly localized and
eliminated. Furthermore it is possible to generate event lists of the complete installa-
tion, which can be used to analyze the frequency distribution of installation faults.
A considerable contribution to the increase of availability is provided by remote diag-
nosis. Via internet the customer can authorize the supplier of the installation to ac-
cess the control systems. This will enable an immediate online fault diagnosis and
elimination by the expert of the supplier, without waiting time for the customer. The
same method can be applied for software updates and also for continuing techni-
cal/technological support. Upon the customer’s request the supplier can analyze shot
curves and shot parameter and can propose corresponding measures to optimize the
production. This can then be crucial when the production of a new part is being
started.


Production optimization


Integral solutions provide the possibility to optimally adapt the individual movements
to each other. Parallel movements extending as wide as possible can prevent idle
times and thus minimize cycle times.
An additional feature that can be utilized by the customer is the so-called universal
interface . This will make it extremely easy for the user to program inputs and outputs
into the cycle for further peripheral functions by using the central screen without any
specialist’s knowledge in electronics.




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                                        Session 6
           WFO
      Technical Forum
           2003           Process control and visual inspection                       3.5



Service


An integrated cell is normally supplied from a single source. This means that the ser-
vice will be from a single source as well. Competencies and responsibilities have
been clearly defined. Services that exceed the warranty period can be stipulated in a
maintenance contract. In this case the supplier of the installation will be responsible
for the service of the complete installation. However, if the customer purchases his
own peripheral equipment then implementation of this will be very difficult.


Summary


Integral cells make a contribution to increase the economy of die casting, in fact dur-
ing the whole lifespan of an investment. Management decisions will be simpler if the
complete responsibility for the cells can be delegated to a supplier. The processing
time from order to delivery can be shortened and commissioning time can be re-
duced. The identical central operation facilitates overall control, setting, error diagno-
sis and production optimization. Remote diagnosis reduces downtimes and simplifies
the implementation of improvements in the form of updates.
Service from a single source reduces internal costs for the customer and keeps the
stock keeping of spare parts to a minimum.




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