Re[2]: Stratasys wish list, again

From: Floyd Roberts (
Date: Tue Sep 16 1997 - 19:29:37 EEST

Research in the field of advanced materials is emblazened with giddy
enthusiasm regarding the FDM process. Following NASA's early success (ok
actually Advanced Ceramics Research in Tuscon did all the work but we like
to take the credit for being smart enough to give them money) with a
retrofit to the stratasys 3D modeler creating green ceramic parts and
carbon fiber reinforced PEEK (1994?) a host of research minded people have
begun to improve upon the materials and the process of FDM with an eye
towards the direct manufacture of parts via the FDM route.
        One suggestion for bringing out more discussion on the FDM route to
RP would be to have people bring up more of the applications for which FDM
is "barely capable" or currently could use some help. I will note here that
we use FDM for the production of wind tunnel models (as well as many of the
other processes) and we are constantly seeking ways to improve the surface
finish of the parts. At one time in a galaxy far far away we performed a
designed experiment looking at surface finish on the machinable wax (now
the support wax) with an eye towards finding build parameters which
enhanced the surface finish. The report is now obsolete however the method
and the approach are things I would love to see tackled using the newer
materials - in short - we measured the surface finish on the top (upward
facing) surface (across the roads) of a trial part, the side measured
parallel with the Z axis (the bumpy direction) and we measured on the side
in plane (along a road edge) - for simplicity we did not measure the
effects of alternative fill patterns on the top surface or other potential
variations....... We constantly are on the lookout for tricks to improve
our surface finish (damn those guys in the wind tunnel are picky about
that) so any suggestions would be welcome. Currently we use a lengthy
combination of alcohol wipe and light hand sanding to get a "barely
acceptable" surface finish...
Floyd "the goverment guy" Roberts

On 9/16/97, ralott@CCGATE.HAC.COM wrote:

> >>Why would we need to send anything other than .sml files using ssend ?
> I don't type too well all the time -- sometimes ".sml" becomes ".ssl" and
> drives the machine nuts!
> >>Is the foam used in 8000 different from that on 1600?
> As far as I can tell, size is the only difference. I have less of a problem
> with the 1650, too.
> >>I also would like too add these few lines. How's is that
> discussions about FDM are almost absent on this list ? Its only that
> occasionally that somebody comes up with a wish list.
> It might be just as valid to ask, "Why is there so much discussion about
> the SLA's?" Actually, I think if we discarded the off-topic discussions,
> advertisements, announcements and industry rumors, there wouldn't be that
> much discussion at all, save for the university students doing research.
> But here are some possible reasons why FDM's are a slow topic:
> 1. There are no other companies competing to sell raw materials.
> 2. There are no apparent patent infringement suits in court.
> 3. There are very few equipment problems, and most can be fixed with a
> phone call to Stratasys.
> 4. The FDM hasn't piqued the interest of the academics the way SLA's have.
> I guess without lasers and exotic chemicals, the FDM's are just too
> mundane.
> Rick Lott
> Hughes Space and Communications
> Los Angeles CA

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