Re: CARP

From: Gregory Pettengill (Cote Art & Engineering)
To: Jon Hunwick (Delcam  International PLC)
Date: Tuesday, July 26, 1994
Forwarded to RP-ML by Greg, 94 08 03
Subject: Re: CARP
Jon Hunwick,
You wrote;
>Apart from simply building models, one of our main interests is in
>getting metal parts. To this end we have made a strategic alliance
>with a foundry in Wales, who are now able to take a DTM or LOM model
>and cloak it in ceramic slurry. Once fired, this produces a 'shell'
>mould into which molten metal can be poured. The ceramic is then
>broken away, and the metal part extracted. In this way we have
>succeeded in producing parts in both aluminum and stainless steel.
>Admittedly the FFFF model is destroyed in the process, but the point
>is that you get a prototype metal part for test 3-4 weeks earlier than
>with traditional methods. 

I suggest that you design the FFFF model as a wax mold, then use it to cast 
wax patterns for metal castings.  This method would have several advantages;
A)  The FFFF model is NOT destroyed in the process.
B)  Multiple parts are possible.
C)  An opportunity to make changes to the design.

This change would cost nothing or very little in terms of time and money.
The CAD work for this is like the way prototype plastic injection dies are 
designed.  That is, a die designer will be given a finished part drawing and 
then proceeds to draw a mold around it.