Rapid Prototyping: Computer-Aided Manufacturing of Laminated Engineering Materials (CAM-LEM)

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9420373 Newman This multidisciplinary project addresses software, equipment and materials processes for achieving high-quality, structural ceramic parts with complex interior and exterior geometries, produced directly from a computer aided design description. The technique involves cutting and stacking laminae to form a structural component. By separating the materials processing steps from the shape fabrication operations, the method promises to achieve high dimensional accuracy while achieving monolithic structural integrity. By laser slicing pre-processed laminae and robotically stacking them into laminated assemblies, it appears possible to achieve significantly faster fabrication over direct depositiol techniques. Further, by utilizing surface normal information to cut laminae at computed tangents, surface quality can be improved. By cutting-then-stacking, there is the opportunity for complete material removal from intended voids, as well as assembly of fugitive support structures. Hardware issues focus on the design, construction and testing of five axis laser- cutting system. This system will create laminae with the desired outlines and edge tangents. It will be integrated with a robot for feeding stock sheet, feeding filler material, removing waste material, and handling and assembling cut laminae. Machine performance issues include pragmatic cutting speed and achievable cutting, and assembly accuracies. Software developments will incorporate existing knowledge and extend capabilities in two areas. Surface normal information contained within standard files will be used to define laser-cutter trajectories for tapered edge cuts, thus improving surface finish. Second, part shrinkage due to post-process firing will be modelled, and "green" parts will be pre-distorted computationally to anticipate correct final dimensions. Rapid prototyping to near net shape parts offers numerous advantages to the manufacturing sector in terms of redu cing cycle time, reducing waste thus lowering manufacturing cost. This project synergetically combines well established technologies to come up with solutions to current limitations on surface finish and part accuracy. While the project focusses on cast alumina, it has the potential for much broader commercialization as opposed to the current niche successes of rapid prototyping process.