Shaw Process Casting

From: Greg Redden (CSIRO  Institute of Industrial Technologies)
To: RP-ML
Date: Friday, May 19, 1995
Subject: Shaw Process Casting
Once again my response time to postings on rp-ml is less than fast.  In fact
on this occasion it is probably so slow that the majority of people will
have forgotten what the original thread was all about.

For those of you who have forgotten, about a month ago I made some comments
on the virtues of Shaw process casting for manufacturing cast tooling based
upon RP patterns and also asked if anybody out there on rp-ml was using this
or related processes.  There were a number of responses, namely from Dick
Newton - Ford <newton@rrm.org> who was interested in knowing more about the
process in general and especially the tolerances and moulding geometry
limitations,  Axel Geuer <ge@iwb.mw.tu-muenchen.de> who was interested in
literature on the subject, Adam Cohen - Soligen, Inc.
<QuickQuotes@PartsNow.com> who was interested in who has been casting things
using this technique and Dave Tait - Laserform, Inc.
<73241.425@compuserve.com> who suggested that J&I Pattern @810-689-1956 have
done some related work.

To attempt to answer questions:

The Shaw process uses a ceramic slurry which is poured over the RP pattern
(or any other pattern for than matter).  The slurry soon gells into a
rubbery like consistency at which time the mould is stripped from the
pattern.  The next step is to "torch" the ceramic which involves burning off
alcohol which is evolved during the gelling process.  This "torching" also
promotes some special properties in the ceramic mould.  After this the mould
is fired in a high temperature kiln and is then assembled ready for casting
in any metal which could normally be cast in  the investment casting
process.  Dimensional accuracy and surface finish is comparable to the
investment casting process.

Unfortunately I never received any further responses (either on rp-ml or by
direct email) on people using the process.

As for references, there are a number of books and papers describing work in
the area, however I recently (in December) wrote a report for my
organisation discussing cast tooling based on RP patterns.  In this document
precision casting processes used for casting tools are discussed as are RP
systems and some other stuff related to casting, including an excellent list
of references.  This report was never originally intended for release
outside my organisation however it contains no confidential information so I
would be happy to email a postscript copy of it to anybody who asks either
by direct email or on rp-ml.

Hope this helps.