Core_Removal_Presentation by panniuniu

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									           Core removal

 Howard Pickard
LBBC Technologies




                 LBBC Technologies
             Leaders in autoclave technology   www.lbbctechnologies.com
              Core removal
          LBBC Technologies
        Suppliers of autoclave systems




Dewaxing BoilerclaveTM                       Core Leaching autoclave

                      LBBC Technologies
                  Leaders in autoclave technology   www.lbbctechnologies.com
                       Core removal
LBBC Technologies
  Suppliers of autoclave
       systems with
    QuicklockTM doors
Independent family owned
Established over 130 years
Variety of autoclave applications
Equipment development
Service and support




                               LBBC Technologies
                           Leaders in autoclave technology   www.lbbctechnologies.com
Shell removal
      vs
Core removal




     LBBC Technologies
 Leaders in autoclave technology   www.lbbctechnologies.com
Shell vs Core removal
Removal of the shell involves…
  metal shrinkage assists the process
  large ceramic particles
  mechanical methods


Removal of a core involves…
  small ceramic particles
  complex geometry
  enclosed areas


                 LBBC Technologies
             Leaders in autoclave technology   www.lbbctechnologies.com
                 Cores

Used by a minority of foundries
Increases applications for investment castings
Implications throughout process
Removal perceived to be the hardest stage
Considering only Silica based cores




               LBBC Technologies
           Leaders in autoclave technology   www.lbbctechnologies.com
  Removal of core
            Key issues
•Geometry
   •Is it possible to remove?
•Metal Alloy
   •Susceptible to attack
•Cost
   •Market potential, capital investment
•Health & Safety
   •Exposure of operators, waste by-products
•Environment
   •By-products of the process




             LBBC Technologies
         Leaders in autoclave technology   www.lbbctechnologies.com
Removal of core
          methods
   Hydraulic cleaning
   Sand blasting
   Caustic bath / mechanical
    agitation
   Caustic autoclave
   Molten caustic
   Ultrasonics




          LBBC Technologies
      Leaders in autoclave technology   www.lbbctechnologies.com
                            Removal of core
     Hydraulic cleaning
                                          methods
     Sand blasting                            Description
     Caustic bath / mechanical agitation      High pressure water jets erode core
                                               particles then recirculate within machine
     Caustic autoclave
     Molten caustic
     Ultrasonics

    Advantages
    Good method for simple core                 Best practice
    geometry. Low health and safety
    issues.                                     •Large non complex cores
    Disadvantages
    Can be difficult and time consuming
    to remove the core.


                                          LBBC Technologies
                                      Leaders in autoclave technology   www.lbbctechnologies.com
                             Removal of core
     Hydraulic cleaning
                                         methods
     Sand blasting                           Description
                                              Grit or shot is fired at the core passage
     Caustic bath / mechanical agitation     within a cabinet either by compressed
     Caustic autoclave                       air or an impeller.
     Molten caustic
     Ultrasonics

    Advantages
    Effective at removing large cores with     Best practice
    low complexity. Low health and safety
    issues. Good casting finish                •Grade of
    Disadvantages                              shot/grit.
    High level of dust. High possibility of
    casting wear.                              •Mechanical
                                               separation

                                         LBBC Technologies
                                     Leaders in autoclave technology   www.lbbctechnologies.com
                           Removal of core
    Hydraulic cleaning
                                        methods
                                            Description
    Sand blasting
                                            Sodium or potassium hydroxide solution
    Caustic bath / mechanical agitation    (35 – 50%) in a tank at room or elevated
    Caustic autoclave                      temperature. Parts placed into solution
    Molten caustic                         and left for liquid to break down the core
    Ultrasonics                            material. Mechanical or air agitation
                                            may be added.
    Advantages
    Low cost, simple method for            Best practice
    removing cores. Minimises erosion
    of casting.
                                           •Consider agitation
    Disadvantages                          •Automate systems
    Can take long time for large or
    complex cores. High level of           •Drill holes first
    health, safety and environmental
    risks

                                       LBBC Technologies
                                   Leaders in autoclave technology   www.lbbctechnologies.com
                          Removal of core
   Hydraulic cleaning
                                      methods
   Sand blasting
   Caustic bath / mechanical agitation
   Caustic autoclave
   Molten caustic
   Ultrasonics




                                      LBBC Technologies
                                  Leaders in autoclave technology   www.lbbctechnologies.com
Core leaching autoclave




         LBBC Technologies
     Leaders in autoclave technology   www.lbbctechnologies.com
             Core examples




Courtesy
of Certech




                   LBBC Technologies
               Leaders in autoclave technology   www.lbbctechnologies.com
            The process

The
Equipment




                LBBC Technologies
            Leaders in autoclave technology   www.lbbctechnologies.com
       The process

Load




                                                Baskets




           LBBC Technologies
       Leaders in autoclave technology   www.lbbctechnologies.com
         The process

                                                                Typically
Fill &                                                          120 psi
Cycle                                                           160 oC
                                                                NaOH 20%
                                                                KOH 40%




             LBBC Technologies
         Leaders in autoclave technology   www.lbbctechnologies.com
       The process

Dump




           LBBC Technologies
       Leaders in autoclave technology   www.lbbctechnologies.com
       The process

Wash




           LBBC Technologies
       Leaders in autoclave technology   www.lbbctechnologies.com
           Core leaching autoclave
Best practice
•NaOH or KOH
   •Speed, recycle
•Concentration
   •High / low, temperature
•Component orientation
   •Up or down, horizontal
•Cycle parameters
   •Dwell, vent, mid way break
•Recycle caustic
   •Cost, efficiency
•Post leach operations
   •Water wash


                           LBBC Technologies
                       Leaders in autoclave technology   www.lbbctechnologies.com
                          Removal of core
   Hydraulic cleaning
                                        methods
   Sand blasting                       Description
                                        Bath of molten concentrated
   Caustic bath / mechanical agitation
                                        caustic. Castings placed inside
   Caustic autoclave
   Molten caustic
   Ultrasonics

Advantages
Quick and effective at removing          Best practice
cores
Disadvantages                            •Take great care
Many health and safety issues. Likely    •Check suitability of
to attack the casting alloy surface
                                         alloy


                                      LBBC Technologies
                                  Leaders in autoclave technology   www.lbbctechnologies.com
                            Removal of core
     Hydraulic cleaning
                                        methods
     Sand blasting                           Description
     Caustic bath / mechanical agitation     Use of ultrasonic rays to break down
     Caustic autoclave                       macroscopic structures
     Molten caustic
     Ultrasonics

    Advantages                                 Best practice
    Speeds up the process
    Non contact                                •Research phase – no
                                               commercial system
    Disadvantages
    Early development of the
    process. Untested.



                                        LBBC Technologies
                                    Leaders in autoclave technology   www.lbbctechnologies.com
          Removal of core
Consider the key issues
Be aware of the alternative methods
Review the operation
Increase application of investment castings

            Increase yield
            Improve quality
                   LBBC Technologies
               Leaders in autoclave technology   www.lbbctechnologies.com
          Shell and Core removal
  Special thanks to :
  Dr Brian Robson
  Casting Solutions Limited
  Email : brianrobson@live.com




References
•Fettling and finishing, Dr Alan Clegg, EICF workshop 2004
•Leaching of preformed ceramic cores, Miller & Eppink, Sherwood Refractories, ICI
1983



                               LBBC Technologies
                           Leaders in autoclave technology   www.lbbctechnologies.com
Thank you




     LBBC Technologies
 Leaders in autoclave technology   www.lbbctechnologies.com

								
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