Multiple Castings Results

From: Wayne L Foss (wlfoss@crnotes.cca.rockwell.com)
Date: Wed Oct 28 1998 - 17:59:56 EET


My original posting on October 22, 1998:

>List - your suggestions please.
>
>I have a possible need to produce a quantity of 14 investment cast parts
>for spares of some out of production equipment. All of the previous
>tooling has been destroyed (1989 production). The part is a 6 sided box
>approximately 15.25 x 12.62 x 7.75 inches. This is an electronics
>enclosure with one open side and it must be an aluminun investment
>casting (we have no choice, it MUST use the same materials and processes
>as those already produced - a government requirement). The part will be
>post machined to add tightly tolerenced details.
>
>What would be the most efficient, quickest and cost effective way of
>making the 14 copies? I am well aware of the DSPC process of
>Soligen/PartsNow and will be contacting them. I also have a FDM 1650
>in-house that could make ABS masters - but not quickly enough. I have
>thought of making a master part and creating a RTV mold to create the
>wax patterns, but they would need to be made in sections and bonded
>together.
>
>I also need to guess at how much will it cost? And guess what? No 3D
>solids data! Why can't they settle for 1 or 2 parts?

Thank you to everyone that responded to my request, there were MANY. A
couple of details had changed that were not passed on to me until after my
posting. This part was a "similar to" item used to bid on a new contract,
so there is the possiblity to enhance its design (.080 thick walls and air
hole patterns with very small holes). Also, there would be good 3D solids
data available (scanning a part was not a viable solution as one was not
available). The prototype build is to be only 7 parts, but production would
only be an additional 15 parts. This would make any RP process very
promising for the production run also.

The proposed processes included producing SLA QuickCast masters which
turned out to be less expensive than I expected. Another proposal was to
make a multi-piece silicon mold with moveable cores to cast the wax
patterns. Someone also proposed making the parts by the LENS process, but
availability and cost may be issues. Another Stratasys user suggested using
a Quantum to build ABS masters which have proven to work well in investment
casting. Also suggested were epoxy molds for the wax masters, and Actua (3D
Systems) produced masters.

My conclusions to this study are - Yes it can be done by many manufacturers
at a very reasonable cost as compared to the quantities needed and
alternative processes. Thanks again to all of those that responded.

Wayne

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