Part Generation by Layerwise Selective Sintering

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This proposal will investigate a new manufacturing process which builds up parts in layers from a powder by selectively sintering each layer with a laser. The objective of the process is to automatically produce three-dimensional parts of general shape directly from a CAD database without part-specific tooling or human intervention. Each layer that is built up corresponds to a cross-section of the part. Powder is deposited into a box in thin layers; after each layer is deposited, the surface of the powder is raster-scanned with a high-power laser beam. The intensity of the laser beam is modulated so that the powder is sintered or fused in the areas that are to be occupied by the part at that particular cross-section. In those areas not sintered, the powder remains loose. Another layer of powder is then deposited and raster-scanned. The process is repeated until the entire part is produced. The methodology to be used is an experimental/empirical approach used in conjunction with computer modeling and analysis. The objectives of the proposed research are to formulate a process model and rules for selection of powders and process parameters, and to explore post-treatments. Preliminary work has been conducted with plastic powder; the proposed work is needed to demonstrate feasibility with common engineering materials. The proposed process which produces a three-dimensional part by the combination of a raster scan and selective sintering from a CAD database without part specific tooling or human intervention appears to be novel. This process should facilitate the quick production of prototype parts which should reduce product development time.