At 15:43 14/07/97 -0700, you wrote:
>I read in this months Popular Mechanics about a company that sells a device
>which creates sold model prototypes.  As far as I can tell, a container is
>slowly filled with an epoxy compound, which is hardened, layer by layer, by
>some sort of laser.  The result is a 3-D epoxy model.
>
>This is a really neat way to create stuff  (By the way, they want a modest
>$99,000.00)  Does anyone have any idea about epoxy's, or other compounds
>which can be harden by laser?  How about UV light? or other methods which
>can be computer controlled?

There are several light sensitive catalysts for polymerisation. IIRC someone
patented the use of sulphur hexafluoride, so several other companies
developed organic materials with similar properties. I don't know which one
is used in commercial prototyping systems.

These systems have always appealed to me as a way of making patterns for
castings. You design your casting and add in the expansion factor on the
computer then make a one-off pattern. Pop the polymer prototype in the
moulding box, and treat it in the same way as a lost wax casting. (OK so you
get a lot of crap in the sand) Shame they're so expensive.

Keith.
==========================================================
Keith Dowsett         "Variables won't; constants aren't."

E-mail: kdowsett@rpms.ac.uk
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