SELECTIVE LASER SINTERING

THREE-DIMENSIONAL PARTS OF GENERAL SHAPE CAN BE PRODUCED DIRECTLY FROM A COMPUTER DATABASE WITHOUT PART-SPECIFIC TOOLING OR HUMAN INTERVENTION BY A NEW PROCESS CALLED SELECTIVE LASER SINTERING. EACH BUILT-UP LAYER CORRESPONDS TO A CROSS-SECTION OF THE PART. A THIN LAYER OF POWDER IS FIRST DEPOSITED INTO A CONTAINER. THE POWDER SURFACE IS RASTER-SCANNED WITH A HIGH-POWER LASER BEAM FROM ABOVE. BEAM INTENSITY IS MODULATED TO FUSE POWDER IN AREAS TO BE OCCUPIED BY THE PART AT THAT PARTICULAR CROSS-SECTION. IN AREAS NOT SINTERED, THE POWDER REMAINS LOOSE AND MAY BE REMOVED ONCE THE PART IS COMPLETE. SUCCESSIVE LAYERS OF POWDER ARE THEN DEPOSITED AND RASTER-SCANNED UNTIL THE ENTIRE PART IS PRODUCED. EACH LAYER IS SINTERED DEEPLY ENOUGH TO FUSE IT TO THE UNDERLYING LAYER. A GENERAL THREE-DIMENSIONAL OBJECT CAN BE PRODUCED IN THIS WAY DIRECTLY FROM A SOLIDS MODELING OR OTHER THREE-DIMENSIONAL COMPUTER DATABASE. A CLOSELY-COUPLED THEORETICAL AND EXPERIMENTAL INVESTIGATIONBUILDING ON THE RESULTS OF EARLIER NSF-SPONSORED GRADUATE RESEARCH BY THE PRINCIPAL INVESTIGATOR WILL BE PERFORMED TO DEFINE AND QUANTIFY THE PERFORMANCE ENVELOPE OF THE NEW PROCESS. THE PHASE I RESEARCH PLAN WILL BE IMPLEMENTED TO ASSESS THE EFFECTS OF DIFFERENT INPUT MATERIALS, FOAMING AGENTS, AND PLASTICIZERS ON ACHIEVABLE DIMENSIONAL TOLERANCE, STRENGTH, ENERGY DEMAND, AND PRODUCTION RATE.