Low-volume, vacuum-formed, patterned sheets

From: mkottma@kimball.e-mail.com
Date: Fri Jun 20 1997 - 16:30:51 EEST

Everything is relative; cost of tooling, thin plastic sheets, low
volume. More specific info would help pinpoint the best solution.
However, I have several suggestions, and depending on the exact
requirements, one or more may be applicable.

1) RTV silicone molds, cast urethane. If you have a master, the silicon
   molds pick up amazing detail. Depending on the how the master is
   produced, tooling costs can be very low. There is a very wide variety
   of urethane materials available, much wider than is possible in
   vacuum forming, one of them should meet your needs.

2) Low cost vacuum forming tools. We have made a number of prototype
   vacuum form molds in a number of materials:
   - RenShape board works very well. Easily machined and durable.
     This is a very good choice for CNC mill work.
   - Urethane foam board. We've used 12 - 20 lb. density. The surface
     will need to be filled, but it is very easy to work with. Added
     bonus is very light molds. Not a good choice for small details
   - Plaster castings. This has worked very well for us in some cases.
     Makes for a very heavy mold, though.

The key to vacuum forming in low volumes is to find a supplier that
specializes in that type of work. Some vac formers run very high volume
thin sheet packaging applications, others do lower volume custom work.
The usual relationship between volumes, tooling cost, and part cost

I hope this helps!

Mark Kottman

*** Forwarding note from I1685508--IBMMAIL 06/20/97 05:04 ***
Date: Fri, 20 Jun 1997 01:31:09 -0700 (PDT)
From: "M. Burns (marshall@ennex.com)" <mburns@netcom.com>
Subject: Low-volume, vacuum-formed, patterned sheets
To: "List: Rapid Prototyping" <rp-ml@ltk.hut.fi>

Dear RP-ers,

     An associate of mine needs to make thin plastic sheets with various
textures in them, such as brick patterns, stripes, etc. I believe he is
currently making them by vacuum forming. Currently he can only make them
in fairly large quantities because the cost of the tooling is high. Does
anyone have any suggestions (or commercial referrals) on how to make such
an item economically in low volumes?

Best regards,
Marshall Burns


** Ennex(TM) Fabrication Technologies **
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