Transcript Main points - LBBC Technologies

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






methods
Hydraulic cleaning
Sand blasting
Caustic bath / mechanical agitation
Caustic autoclave
Molten caustic
Ultrasonics
Advantages
Good method for simple core
geometry. Low health and safety
issues.
Description
High pressure water jets erode core
particles then recirculate within machine
Best practice
•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






methods
Hydraulic cleaning
Sand blasting
Caustic bath / mechanical agitation
Caustic autoclave
Molten caustic
Ultrasonics
Advantages
Effective at removing large cores with
low complexity. Low health and safety
issues. Good casting finish
Disadvantages
High level of dust. High possibility of
casting wear.
Description
Grit or shot is fired at the core passage
within a cabinet either by compressed
air or an impeller.
Best practice
•Grade of
shot/grit.
•Mechanical
separation
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
Advantages
Low cost, simple method for
removing cores. Minimises erosion
of casting.
Disadvantages
Can take long time for large or
complex cores. High level of
health, safety and environmental
risks
Description
Sodium or potassium hydroxide solution
(35 – 50%) in a tank at room or elevated
temperature. Parts placed into solution
and left for liquid to break down the core
material. Mechanical or air agitation
may be added.
Best practice
•Consider agitation
•Automate systems
•Drill holes first
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
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
120 psi
160 oC
NaOH 20%
KOH 40%
Fill &
Cycle
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






methods
Hydraulic cleaning
Description
Sand blasting
Bath of molten concentrated
Caustic bath / mechanical agitation
caustic. Castings placed inside
Caustic autoclave
Molten caustic
Ultrasonics
Advantages
Quick and effective at removing
cores
Disadvantages
Many health and safety issues. Likely
to attack the casting alloy surface
Best practice
•Take great care
•Check suitability of
alloy
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
Advantages
Speeds up the process
Non contact
Disadvantages
Early development of the
process. Untested.
Description
Use of ultrasonic rays to break down
macroscopic structures
Best practice
•Research phase – no
commercial system
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 : [email protected]
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