Recent Submissions

  • Advances in Selective Area Laser Deposition of Silicon Carbide 

    Tompkins, J.V.; Laabi, R.; Birmingham, B.R.; Marcus, H.L. (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 

    Suh, Young Seok; Wozny, Michael J. (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 

    Halloran, John W.; Griffith, Michelle L. (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 

    Vail, N.K.; Barlow, J.W. (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 

    Bunnell, D.E.; Bourell, D.L.; Marcus, H.L. (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 

    Badrinarayan, B.; Barlow, J.W. (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 

    Jakubenas, K.; Marcus, H.L. (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 

    Childs, T.H.C.; Cardie, S.; Brown, J.M. (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 

    Birmingham, B.R.; Tompkins, J.V.; Marcus, H.L. (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 

    Lee, Insup; Manthiram, A.; Marcus, H.L (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. 

    Kamatchi Subramanian, P.; Vail, N.K.; Barlow, J.W.; Marcus, H.L. (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 

    Sumin Sih, Samuel; Barlow, Joe W. (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 

    Thissell, W. Richards; Marcus, H.L. (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 

    Mendez, Patricio; Brown, Stuart (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 

    Johanson, Roy; Kikuchi, Noboru; Papalambros, Panos (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 

    Bernitsas, Michael M.; Suryatama, Danet; Byungsik, Kang; Dale, G. Karr (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 

    Benda, J.A. (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 

    Carleberg, Per (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 ...
  • On the Computation Of Part Orientation Using Support Structures in Layered Manufacturing 

    Allen, Seth; Dutta, Deba (1994)
    During the construction of an object by layered manufacturing, it might be necessary to build external supports either to prevent the object from toppling, or to support floating components and overhanging material. The ...

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