Re[2]: Model/Pattern Verification

From: Michael C Maguire (
Date: Mon Oct 20 1997 - 21:44:06 EEST

Steve Farentinos wrote:

.. I have found, however, that much of the
accuracy problems arise after the part is taken off the machine, i.e.,
during post processing.


Just to add my two cents worth, when patterns from RP are used directly in the
investment casting process it is the distortion from the casting process
(solidification and cooling) that far overwhelms the distortion or innaccuracy
initially present in the pattern. Granted, my direct experience is with SLA and
SLS patterns, but I think it's pretty universal. In most cases, the patterns we
use, particularly so for SLA, have better dimensional stability and accuracy
than injected waxes. It was hard for us to believe, but it's true. RP put the
accuracy spotlight on our old hard tooling processes too.

Michael C. Maguire, Ph.D.
Liquid Metal Processing Laboratory
Mail Stop 1134
Sandia National Laboratories
Albuquerque, NM 87185-1134
Phone: 505-845-3105
FAX: 505-845-3430

This archive was generated by hypermail 2.1.2 : Tue Jun 05 2001 - 22:40:35 EEST