Burnout of UV Cured Polymers

From: AHastbacka@aol.com
Date: Sun Mar 26 2000 - 21:48:46 EEST

There have been several questions about how well the Models produced on the
Objet will burnout for investment casting.

I do not have any of the Objet sample parts, but we have been evaluating a
wide range of UV curable polymers (acrylates, urethanes, and epoxies) over a
period of several years. In general, these polymers do not burnout as easily
as the patterns made on a 3D Systems Thermojet or a Sanders ModelMaker. That
was the reason that 3D came up with Quick Cast. By making the SLA pattern
with a low density structure, the problem of the expanding pattern breaking
the shell mold is minimized. However, this only works down to about a 20 mil
wall thickness. Below this thickness, the relatively hollow structure
becomes fully dense and you run into the classical problems of trying to
burnout out one of these types of polymers.

In addition, burnout of most UV curable polymers often leaves a fair amount
of carbon. Carbon can kill certain types of investment casting processes
(e.g. titanium).

Al Hastbacka

For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/

This archive was generated by hypermail 2.1.2 : Tue Jun 05 2001 - 23:03:07 EEST