From: Mr C.C. Ainsley (
Date: Wed Mar 12 1997 - 11:34:58 EET

Hi RPers
        I am writing to inform you of the conclusions of my project
which was the slip casting of stainless steel for the formation of injection
moulding cavities.
The final part of the project involved the construction of a three cavity
injection moulding tool of a key ring and compare it in terms of
cost and performance with other rapid tooling methods for the same cavity
The following results were obtained:

Process cost Quoted dimensional tolerance
                   pounds sterling microns Per 25.4 mm or inch
Slip cast 2253 25
Conventional 4500 90
SLS 6500 136
Investment casting 2135 130
Keltool 2865 25
Spray metal 3900 Unknown
Direct SLA 5170 2215 100
High temp cast epoxy 1565 Unknown

Costs are based on average cost from commercial Quotations where applicable.
The Slip cast tool was costed on commercial bases with process cost done on
a sub contract bases and a 30% profit put on top to allow a direct
comparison. Accuracy of the slip cast tool was based on the worst case
samples taken during the development process.

The final slip cast tool was 99 % dense with tensile strength similar to
that of mild steel. The injection moulding tool ran for over one hundred
shot with no wear and the average moulding size differed between the
different cavities by 0.5 micron.

Thanks to everybody who has given me help


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