Re: Cast Tooling

From: Don Wilde (
Date: Fri May 31 1996 - 20:30:33 EEST

On Fri, 31 May 1996, Erkut Negis wrote:
> As far as I see one of the biggest problem in investment cast tooling is
> dimensional errors resulted from shrinkage of the alloy during its
> solidification. There are three main approaches to solve this problem.
> 1- Measure dimensional error of cast part (mold core or cavity) and based on
> that modify your CAD file to compensate for the shrinkage:
> This procedure may require more than one iteration and it could be more
> costly than using CNC machining.

Yes, Erkut. That is indeed the biggest problem. We have software that
adds shrinkage factors automatically, but of course complex geometries
don't shrink equally. We usually have acceptable results on the second
try, especially for parts designed to be takeoffs.

To be honest, though shell thickness control is one of our possible
strengths, we haven't even begun to use that capability. This means we
have even more room for improvement!

As far as costs go, we are attacking that problem intensely. Reasonably
competitive now, we are working on several ways to dramatically reduce
our shell costs.

 So many projects, so little time!

    oooOOO O O O o * * * * * *
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   V_=_=_DW ===--- Don Wilde [ ]

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