2003 / Solid Freeform Fabrication Proceedings
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Author K. Lappo, K. Wood, D. Bourell, J. J. Beaman Mechanical Engineering Department Laboratory for Freeform Fabrication The University of Texas at Austin, Austin TX 78712
Source Solid Freeform Fabrication Proceedings, 2003, pp 93-108.
Abstract Previous research focused on the advancement of the Selective Laser Sintering (SLS) technology to incorporate discrete multiple material processing. The powder delivery subsystem rolled each material sequentially into selectively removed voids in the part bed, produced by vacuum suction, to form a single horizontal layer. This method, although it minimized changes to the traditional SLS technology, produced components with significant material cross contamination between discrete regions. A new powder delivery method was designed to alleviate this problem in which alternatively a nozzle precisely deposits material into vacuum suctioned. Micro-powders, such as those used in SLS, do not readily flow through openings due to the adverse cohesive and drag forces. A uniform powder flow rate for micro-sized particles is achieved by the introduction of pressurized air through the nozzle wall near the outlet. Experiments were performed to determine the optimal hopper back pressure and nozzle injected air pressure to obtain uniform flow rate for the commonly used Duraform PA bulk material. (Auth abstract) [References: 11] XX
Solid Freeform Fabrication Proceedings can be obtained from: The Solid Freeform Fabrication Symposium
or contact:
The University of Texas at Austin
Laboratory for Freeform Fabrication / Texas Materials Institute
Mechanical Engineering Dept.
c/o The Solid Freeform Fabrication Symposium
MC C2200
Austin, TX 78712-1063 USA
512-471-3026; 512-471-7681 FX; Email: sffsymp@uts.cc.utexas.edu