Re: Saving Money (DTM and Midwest)

From: Ian Gibson (
Date: Fri Jun 20 1997 - 04:21:51 EEST

Thanks for the insightful comments David - I think I understand a few things
a lot clearer now.

When we bought our SLS machine, one of the questions I asked of DTM was 'can
we use the machine to develop new materials?'. The answer was positive,
although I never got anything written down. Basically the response was that
we can, so long as we dont damage any part of the machine (thus invalidating
the warranty, which I think is pretty fair). They also wanted to know about
any plans we have for powder development. I saw this as fair also since the
chances are they had already done some work in any area we were likely to

Reading about the patent relating to crystalline powders, I have a question.
Does this patent range into the area of copolymers? Trueform is a copolymer
and I wonder if the new nylon powder could be classed as a copolymer since
it appears to have additives that broaden the melt window.

With the introduction of these new materials we appear to be going round
again. The new materials are much easier to use with broader process windows
that reduce the demand on the machine. Since the patent is on the machine
and not the powders, I wonder if this would make it very difficult for DTM
to defend any action relating to powders that have a broad process window.

Perhaps DTM should start working on a new, cheaper machine that doesnt have
all the bells and whistles of the existing one, with a more limited range of


Dr Ian Gibson
Dept. Mechanical Engg.
University of Hong Kong
Hong Kong

tel: +852 2859 7901
fax: +852 2858 5415

Chinese proverb: Those who say it cannot be done should not disturb those
doing it.

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