1994 International Solid Freeform Fabrication Symposium
Proceedings for the 1994 International Solid Freeform Fabrication Symposium. For more information about the symposium, please see the Solid Freeform Fabrication website .
This Proceedings of the Fifth Solid Freeform Fabrication Symposium, held at The University of Texas in Austin on August 8-10, 1994, was the best attended and continued the dynamic nature of the first four. Intense interest was shown by researchers for the latest in the basic aspects of Solid Freeform Fabrication (SFF) that highlighted the papers presented at this Symposium. The speakers addressed problems in computer software, machine design, materials synthesis and processing, and SFF in integrated manufacturing. The continued growth in the research, application and development of SFF approaches was readily apparent from the additional papers presented and the attendees from industrial users, SFF machine manufacturers, universities, and government. There was a very large international involvement in the meeting, both as attendees and as contributors. Research presented in the Symposium showed the continued movement forward toward the goal of structurally sound parts using a wide range of SFF techniques. This continued advancement in the state-of-the-art of SFF and the drive for continually improving and reaching out for standardization of the technology will continue to drive its exponential growth and cooperative efforts. The excitement generated at the Symposium reflects the participants' total involvement in SFF and the future technical health of SFF. The Symposium organizers look forward to its being a continued forum for technical exchange among the expanding body of researchers involved in SFF.
The Symposium was again organized in a manner to allow the multi-disciplinary nature of the SFF research to be presented coherently, with various sessions emphasizing computer aspects, machine topics, and the variety of materials aspects of SFF. Application-related efforts were scattered throughout the Symposium. To avoid parallel sessions, a poster session was organized, and a panel session on SFF was held. The dynamic, loosely organized panel discussion on "Where does SFF go in the Next Five Years?" was led by Joel Barlow, Michael Cima, Thomas Pang, Fritz Prinz, Sean O'Reilly, and Michael Wozny. The written versions of the presented papers are incorporated into these Proceedings. The editors would like to thank the speakers for their timely delivery of the manuscripts. We believe that documenting the constantly changing state of the SFF art as represented by these Proceedings will serve both the people presently involved in this fruitful area as well as the large flux of new researchers and users entering the field of SFF. The evenings were highlighted with Texas-style vittles and entertainment featuring the Geezinslaws.
The editors again would like to extend a warm "Thank You" to Renee Loyless-May for her extensive efforts in the detailed handling of the logistics of the meeting and the Proceedings and the support efforts of Vicki Lehmeier and Cindy Pflughoft throughout. We would also like to thank the organizing committee, the speakers, the session chairmen, panel members, and the attendees for their enthusiastic contributions. We look forward to the continued close cooperation of the SFF community in organizing the Symposium. We also want to thank ONR through Grant No. N00014-94-1-0829, ARPA, .and The Minerals, Metals and Materials Society for cosponsoring the Symposium with the Mechanical Engineering Department and the Center for Materials Science and Engineering at the University of Texas at Austin.
Organizing Committee: Dick Aubin, United Technologies; Joel W. Barlow, The University of Texas at Austin; Joseph J. Beaman/The University of Texas at Austin; David L. Bourell, The University of Texas at Austin; Robert L. Brown, The Gillette Company; William Coblenz, ARPA; Richard Crawford, The University of Texas at Austin; Samuel Drake, University of Utah; Steven Fishman, Office of Naval Research; Harris L. Marcus, The University of Texas at Austin; Fritz Prinz, Carnegie Mellon University; Emanuel Sachs, Massachusetts Institute of Technology; Susan Smyth, General Motors Corporation; Sean O'Reilly, Ford Motor Company; Ralph Wachter, Office of Naval Research; Michael Wozny, Rennselaer Polytechnic Institute
Recent Submissions
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Advances in Selective Area Laser Deposition of Silicon Carbide
(1994)Selective Area Laser Deposition (SALD) is a Solid Freeform Fabrication (SFF) technique which uses a scanning laser beam to produce solid material by locally decomposing a gas precursor. In this work, a focused C02 laser ... -
Adaptive Slicing of Solid Freeform Fabrication Processes
(1994)The Solid Freeform Fabrication (SFF) process significantly reduces part specific setup manufacturing lead time. This process has been primarily used in fabricating prototypes for design visualization and verification. ... -
Ultraviolet Curing of Highly Loaded Ceramic Suspensions for Stereolithography of Ceramics
(1994)Ceramic green bodies can be created using stereolithography methods where a ceramic slip consisting of 45-55 vlo ceramic powder is dispersed within an ultraviolet-curable aqueous acrylamide solution. Two ceramic materials ... -
Modeling of Polymer Degradation in SLS
(1994)A simple computer model has been developed to predict the thermal degradation of polymer binders used in the fabrication of composite green shapes from high temperature ceramic materials. Decomposition rate kinetics of ... -
Fundamentals of Liquid Phase Sintering Related to Selective Laser Sintering
(1994)Liquid phase sintering is one of the underlying principles that must be modeled and understood when the Selective Laser Sintering (SLS) process is used. This paper describes the initial studies being conducted to ... -
Manufacture Of Injection Molds Using SLS
(1994)This paper describes the use of SLS technology for the fabrication of injection mold cavities. Green shapes were made from metal - copolymer powder mixtures by SLS. The copolymer was gradually burnt out and the metal was ... -
Selective Laser Pyrolysis for Solid Free-FonTI Fabrication of Silicon Carbide
(1994)Selective laser pYrolysis rapidly decomposes a polymeric precursor to form a cohesive ceramic shape. The considerable shrinkage and porosity during pYrolysis of pure precursor can be modified by the addition of either ... -
Selective Laser Sintering of Polycarbonate at Varying Powers, Scan Speeds and Scan Spacings
(1994)A benchmark study (1) has shown selective laser sintering to be the equal of or to have accuracy advantages over other processes for creating parts of size over 10 mm. Experience is needed to achieve best accuracies, as ... -
Silicon Carbide Shapes By Selected Area Laser Deposition Vapor Infiltration
(1994)Selected Area Laser Deposition Vapor Infiltration (SALDVI) is a unique combination ofselected area laser deposition, chemical vapor infiltration and layered powder handling techniques that can be used to fabricate silicon ... -
Selective Laser Sintering of Alumina-Boron Oxide Composites
(1994)The selection of an optimum composite system for selective laser sintering (SLS) is based on materials properties such as the melting point and the wettability between the components in the composite powder. The alumina-boron ... -
Anisotropy in Alumina Processed by SLS.
(1994)Alumina powders of 15~m size and 2~m size were processed by SLS using PMMA and a copolymer. The 2~m powders were agglomerated and mixed with the polymer powder before being processed by SLS. SLS bend strength specimens ... -
Measurement and Prediction of the Thermal Conductivity of Powders at High Temperatures
(1994)An equation for the prediction of the thermal conductivity of powder beds up to high temperatures is suggested by the authors. The predicted values by the equation are compared with the values of the thermal conductivity ... -
New Developments in Processing and Control of Selected Area Laser Deposition of Carbon
(1994)Selected area laser deposition (SALD) has been used to deposit carbon from methane, hydrogen, oxygen, and argon mixtures using a third generation deposition system. The effect of two laser scanning hardware/software ... -
Modeling of Selected SFF Process Limits
(1994)An analytical model of the thermal field for one scan line during SLS is developed. Quantitative relationships between net heat input and beam velocity are stated for sintering at a given distance from the center of the ... -
Structural Design for Freeform Fabrication using Composite Materials
(1994)Advances in the development of methods to Perform topology optimization offer the ability to design novel structures composed of dense composite materials. These structures, which possess superior mechanical proPerties, ... -
Shape and Topology Structural Redesign by Large Perturbations
(1994)The ultimate goal in concurrent engineering of structures is to achieve simultaneously in the design stage the following objectives: (1) A shape that performs itsfunction, conforms with the boundary conditions,and can ... -
Temperature-Controlled Selective Laser Sintering
(1994)A control scheme for laser sintering has been developed which maintains sintering powder at constant temperature by actively controlling laser power. It uses a sensor to monitor the temperature of powder at the focus of ... -
Product Model Driven Direct Manufacturing
(1994)The input to the freeform fabrication process is essentially geometric data, raw material, material data and process parameters. Optimal process parameters depend upon current material and the part geometry. This paper ...