Content area
Full Text
Joon Park: Joon Park is a Graduate Student, Mechanical and Aerospace Engineering Department, University of California, Los Angeles, USA.
Michael J. Tari: Michael J. Tari is a Former Graduate Student, Mechanical and Aerospace Engineering Department, University of California, Los Angeles, USA.
H. Thomas Hahn: H. Thomas Hahn is a Professor, Mechanical and Aerospace Engineering Department, University of California, Los Angeles, USA.
ACKNOWLEDGMENT: The authors gratefully acknowledge the support from John Prater, contract monitor, and the Army Research Office under the contract number DAAH04-95-1-0095. Received: September 1998; Revised: February 1999; Accepted: May 1999
Introduction
The laminated object manufacturing (LOM) is one of the additive rapid prototyping (RP) techniques where a three-dimensional part is built sequentially layer by layer from a roll of paper (see Figures 1 and 2 (Wang and Yan, 1993)). The building sequence begins with the lamination of 20 layers of paper to the retractable platform. The 20 layers are cross-hatched completely and act as a disposable base for the part to be fabricated. The paper has a thermally activated adhesive coating on the lower side, and lamination is accomplished with a heated, stainless steel roller. The roller provides the pressure to bring the new layer into contact with the layers already laid down and the heat to cause bonding (Reece, 1996). Each layer is cut with a CO[sub]2 laser beam to a cross-section determined by the computer-aided design (CAD) file. The laser also cuts the excess material in a cross-hatch pattern. The excess material provides support for subsequent layers. Finally, an overall rectangular outline is cut, freeing the cross-section from the paper roll. The platform moves down and the feed paper advances. The sequence repeats itself until the final layer is completed. The excess material, which is already sectioned into cross-hatched columns, is removed manually at the end of the process (Chartoff et al., 1996).
The LOM system produces full size, inexpensive visualization models, shell models for styling, durable models for assembly testing, and solid models for fit verification and packaging studies. The LOM is used extensively for tooling and manufacturing by producing patterns and masters for sand casting, investment casting, cavity molds for injection, and tools for thermal forming and prototype stamping (Helisys, nd). However, little information is available in the literature...