Chapter 15. Solid Freeform Fabrication and Design

  1. Todd Jessen and
  2. Ersan Ustundag
  1. Susanna Ventura1,
  2. Subhash Narang1,
  3. Fred F. Lange2,
  4. Elaine Cohen3,
  5. Douglas Twait4 and
  6. Pramod Khandelwal5

Published Online: 28 MAR 2008

DOI: 10.1002/9780470294635.ch15

24th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: B: Ceramic Engineering and Science Proceedings, Volume 21, Issue 4

24th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: B: Ceramic Engineering and Science Proceedings, Volume 21, Issue 4

How to Cite

Ventura, S., Narang, S., Lange, F. F., Cohen, E., Twait, D. and Khandelwal, P. (2008) Solid Freeform Fabrication and Design, in 24th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: B: Ceramic Engineering and Science Proceedings, Volume 21, Issue 4 (eds T. Jessen and E. Ustundag), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294635.ch15

Author Information

  1. 1

    SRI International 333 Ravenswood Ave. Menlo Park, California 94025

  2. 2

    Materials Department University of California Santa Barbara, California 93109

  3. 3

    Department of Computer Science The University of Utah 3190 Merrill Engineering Building Salt Lake City, Utah 84112

  4. 4

    Honeywell Ceramic Components 2525 West 190th Street Torrance, California 90504

  5. 5

    Rolls-Royce Allison P.O. Box 420, Speed Code W-05 Indianapolis, Indiana 46206–0420

Publication History

  1. Published Online: 28 MAR 2008
  2. Published Print: 1 JAN 2000

ISBN Information

Print ISBN: 9780470375693

Online ISBN: 9780470294635

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Keywords:

  • direct photo shaping;
  • visible digital light;
  • light photoinitiator;
  • preliminary design;
  • computer aided

Summary

This paper describes a new multilayer solid freeform fabrication process, “Direct Photo Shaping” (DPS), where visible digital light projection is used as a maskless tool to build images on photocurable ceramic dispersions (ceramic powders in photopolymerizable liquid monomers) by flood exposure. For each layer the projected image is changed according to the CAD data describing the object being built and solidification takes place by photocuring of the exposed areas. Multiple layers are dispensed and photocured to fabricate the object of interest. A final rinse with a suitable solvent allows the removal of any uncured ceramic dispersion. The porous free formed “green” ceramic object can then be fired and sintered into a highly dense ceramic part. This ceramic forming process is based on visible-light photo gelcasting. The photocurable ceramic dispersion is prepared from a mixture of ceramic powder and organic monomers containing a visible light photoinitiator. Upon photoexposure the monomers solidify into a polymer thus forming a gelcast green body. Digital Light Processing™ technology (developed by Texas Instruments) enables SRI International to project digital, high resolution, high brightness, high contrast visible light to photocure and form components with a good degree of accuracy. This paper describes the Direct Photo Shaping process and its advantages, and how DPS is being applied to the fabrication of ceramic (Honeywell AS800) gas turbine components for military and commercial applications. AS800 test specimens with flexural strength in excess of 800MPa were fabricated by DPS. A first-stage AS800 turbine vane for the Rolls-Royce Allison Model 501-K industrial gas turbine was fabricated by DPS and tested in a gas-burner test rig at 1204°C. Tiles of AS800 with compressive surface layers were fabricated by DPS, and the compressive stress was measured via X-ray diffraction at the Oak Ridge National Laboratory High Temperature Materials Lab. Prototype AS800 cooled vanes were fabricated by DPS per Rolls-Royce Allison's preliminary design.