LBBC Technologies Leaders in autoclave technology Core removal Howard Pickard LBBC Technologies.

LBBC Technologies Leaders in autoclave technology www.lbbctechnologies.com

Core removal

Howard Pickard

LBBC Technologies


Core removal

LBBC TechnologiesSuppliers of autoclave systems

Dewaxing BoilerclaveTM Core Leaching autoclave


Core removal

LBBC TechnologiesSuppliers of autoclave

systems with QuicklockTM doors

Independent family ownedEstablished over 130 yearsVariety of autoclave applicationsEquipment developmentService and support


Shell removal vs

Core removal


Removal of the shell involves…

Removal of a core involves…

metal shrinkage assists the processlarge ceramic particlesmechanical methods

small ceramic particlescomplex geometryenclosed areas

Shell vs Core removal


Cores

Used by a minority of foundriesIncreases applications for investment castingsImplications throughout processRemoval perceived to be the hardest stageConsidering only Silica based cores


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


Removal of coremethods

Hydraulic cleaning Sand blasting Caustic bath / mechanical

agitation Caustic autoclave Molten caustic Ultrasonics



Hydraulic cleaning Sand blasting Caustic bath / mechanical agitation Caustic autoclave Molten caustic Ultrasonics

Best practice•Large non complex cores

DescriptionHigh pressure water jets erode core particles then recirculate within machine

AdvantagesGood method for simple core geometry. Low health and safety issues.

DisadvantagesCan be difficult and time consuming to remove the core.



Best practice•Grade of shot/grit.•Mechanical separation


DescriptionGrit or shot is fired at the core passage within a cabinet either by compressed air or an impeller.

AdvantagesEffective at removing large cores with low complexity. Low health and safety issues. Good casting finishDisadvantagesHigh level of dust. High possibility of casting wear.


Removal of coreRemoval of coremethodsmethods

AdvantagesAdvantagesLow cost, simple method for Low cost, simple method for removing cores. Minimises erosion removing cores. Minimises erosion of casting.of casting.DisadvantagesDisadvantagesCan take long time for large or Can take long time for large or complex cores. High level of complex cores. High level of health, safety and environmental health, safety and environmental risksrisks

Hydraulic cleaningHydraulic cleaning Sand blastingSand blasting Caustic bath / mechanical agitationCaustic bath / mechanical agitation Caustic autoclaveCaustic autoclave Molten causticMolten caustic UltrasonicsUltrasonics

DescriptionSodium 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





Core leaching autoclave


Core examplesCore examples

Courtesy of Certech


The processThe process

TheEquipment



Load

Baskets



Typically120 psi160 oCNaOH 20%KOH 40%

Fill &Cycle



Dump



Wash


Core leaching autoclaveCore 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



AdvantagesAdvantagesQuick and effective at removing Quick and effective at removing corescoresDisadvantagesDisadvantagesMany health and safety issues. Likely Many health and safety issues. Likely to attack the casting alloy surfaceto attack the casting alloy surface


DescriptionBath of molten concentrated caustic. Castings placed inside

Best practice•Take great care•Check suitability of alloy



AdvantagesAdvantagesSpeeds up the processSpeeds up the processNon contactNon contact

DisadvantagesDisadvantagesEarly development of the Early development of the process. Untested.process. Untested.


DescriptionUse of ultrasonic rays to break down macroscopic structures

Best practice•Research phase – no commercial system


Removal of coreRemoval of core

Consider the key issues

Be aware of the alternative methods

Review the operation

Increase application of investment castings

Increase yieldIncrease yieldImprove qualityImprove quality


Shell and Core removalShell and Core removalSpecial thanks to :Special thanks to :

Dr Brian RobsonDr Brian RobsonCasting Solutions LimitedCasting Solutions Limited

Email : Email : [email protected]@live.com

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


Thank youThank you

Date post:	16-Dec-2015
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LBBC Technologies Leaders in autoclave technology Core removal Howard Pickard LBBC Technologies.

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