Selected Papers From The 15th Annual Solid Freeform Fabrication Symposium, Austin, Texas, Usa August 2004

The Solid Freeform Fabrication Symposium is the oldest, continuously running research meeting dealing with the area of rapid prototyping, rapid manufacturing and solid freeform fabrication. Held in Austin, Texas every August, the 2004 Fifteenth Annual Meeting brought together over 120 national and international researchers from 16 countries for three full days of talks, discussion and networking. Papers addressed SFF issues in computer software, machine design, materials synthesis and processing, and integrated manufacturing. Based on peer evaluations of both oral/poster presentations and the submitted manuscripts, the seven top manuscripts from the meeting have been selected from almost 90 total for inclusion in this special issue of the Rapid Prototyping Journal. Vito Gervasi has led research in freeform fabrication at the Milwaukee School of Engineering. His paper deals with standardization or benchmarking of geometry for freeform and hybrid processes, with specific attention given to rod and hole geometries. Dr Wei Sun at Drexel University has led research in the area of freeform fabrication of biopolymer tissue scaffolds. He and his co-workers have developed a multiple nozzle deposition system capable of extruding biopolymer solutions and living cells for freeform construction of three-dimensional tissue scaffolds. Professor Regenfuss and his associates have developed a process for creating microtools called laser micro sintering. Using a Q-switched Nd:YAG laser, a variety of parts less than 1mm in size have been created, including an injection molding die set used to shoot more than 500 Delrin 911P parts. Professor Kruth has an established research record in the field of selective laser sintering (SLS). He and his research associates report in comprehensive fashion on the variety of binding mechanisms at work in selective laser sintering and selective laser melting (SLM). The work serves as a foundational basis for rapid manufacturing using SLS/SLM. Metal infiltration of selective laser sintered articles has been studied by Professor Bourell and others at The University of Texas at Austin. Described here is work with silicon carbide particulate preforms infiltrated in a postprocessing step with molten silicon. Advantages include part geometry and surface finish retention and the ability to process the material in existing commercial sintering stations. Critical to successful processing is development of multifunctional binder systems. Graded metallic systems have been proposed and enabled through processes like Laser Assisted Net Shaping (LENS). Using potential aerospace applications as a case study, Domack and Baughman report on nickel-titanium graded compositions based on engineering alloys. The second case study deals with dental porcelain bodies freeformed by slurry extrusion and post processing. Led by Dr Shaw, research at The University of Connecticut at Storrs involves extrusion of the porcelain in slurry form followed by laser