Ceramic green forms by RP methods

From: Chartoff, Richard P (Chartoff@udri.udayton.edu)
Date: Mon Nov 17 1997 - 21:41:57 EET

Dear RP'ers

The University of Dayton, in collaboration with Helisys and Lone Peak
Enginerering, has been working on producing ceramic and fiber reinforced
ceramic composite greenforms using LOM. We have demonstrated that:

-net shape parts can be produced using infiltration methods for
densification rather than sintering; the infiltration process involves
no shrinkage
-by using a sheet feeding mechanism and pre-triming the sheets much of
the raw material waste associated with the usual LOM process is
- seamless layer interfaces can be achieved
-the parts produced have mechanical properties similar to those produced
by more conventional processes
-novel decubing techniques allow the production of complex shapes
-curved layer greenforms can be made by using a modified LOM system that
can perform variable z-axis cutting and bonding
- while the other RP methods are limited to greenforms a few inches in
size, we have made greenforms up to 15" across, and will be working on
scaling up the process to larger sizes

The current work has emphasized fabrication with silicon carbide tapes
and silicon carbide fibers. Future work will involve other ceramics and

We also have shown that LOM produces robust polymer matrix composites.
Helisys is marketing one system currently. Another high performance
epoxy/ glass fiber system with mechanical properties similar to
commercial aerospace composites also was demonstrated. Future work on
polymer composites will feature carbon fiber reinforced materials.

We expect to update our web site in the near future to include the
latest results.

Richard P. Chartoff
Professor of Materials Engineering
University of Dayton
Center for Basic and Applied Polymer Research and
Ohio Rapid Prototype Process Development Consortium
Dayton, Ohio 45469-0130

Tel: 937-229-2517
FAX: 937-229-2503


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