Browsing by Subject "laser beam"
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Item Direct Laser Sintering of Metals(1993) Carter, William T.; Jones, Marshall G.The use of a directed laser bealn source to selectively sinter multiple layers of binderless metal powder for the purposes of rapid prototyping is described. The work in this paper is restricted to -325 mesh iron powder, which was sintered using a C\V 50 W Nd:YAG laser to approximately 3.5% density. A subsequent post-treatlnent was perfornled to achieve a fully dense saulple. It is envisioned that such a system can be used to manufacture functional metallic prototypes directly from CAD without part-specific tooling.Item Improvements in SLS Part Accuracy(1995) Nelson, Christian; McAlea, Kevin; Gray, DamienSLS® part accuracy is influenced by a number ofmachine and material characteristics. Some of the most significant sources of error are associated with laser beam positioning (static and dynamic) on the part bed surface and uncertainty in the calibration factors used to compensate for material shrinkage and growth as well as the finite width ofthe laser beam. Another source of error is the minimum resolution of the process, which is a dependent on the particle size and shape ofthe material. In this presentation, technical background on these issues will be provided. In addition, part data obtained with a number of SLS materials demonstrating improved accuracy obtained through machine modifications and improved calibration methods will be described.Item SALDVI Optimization for the Tetramethylsilane - Silicon Carbide System(1997) Crocker, James E.; Jakubenas, Kevin J.; Harrison, Shay; Shaw, Leon L.; Marcus, Harris L.Selective Area Laser Deposition Vapor Infiltration (SALDVI) ofsilicon carbide powder infiltrated with silicon carbide deposited from tetramethylsilane (TMS) was studied. The effects of deposition time, temperature, and gas precursor pressure are discussed. The discussion centers on the efforts to properly balance these parameters to produce multi-layered shapes with structural integrity, particularly for use as the matrix material for shapes containing embedded devices. This includes optimizing scan speed, deposition temperature, and gas pressure to maximize infiltration to increase density and layer to layer bonding, and minimize excessive deposition to maintain critical dimensions. Initial powder properties are also optimized to minimize bulk motion in the powder bed during deposition, which was observed and identified as a mechanism that reduces inter-layer bonding.Item USE OF A VIBRATING BUILD PLATFORM DURING POWDER-BED FUSION OF METALS USING A LASER BEAM(University of Texas at Austin, 2023) Hantke, N.; Grimm, T.; Sehrt, J.T.Powder-bed fusion of metals using a laser beam (PBF-LB/M) is an additive manufacturing technique with rising interest in industry and academia. One major topic of current research is to optimize the performance of parts manufactured by PBF-LB/M. The use of vibrations during the solidification of metals to improve their mechanical properties is well-known for metal casting and directed energy deposition. In this work, a vibrating build platform was used during the PBF-LB/M process to influence the microstructure of parts. Analyses show an increase in sample hardness by up to 12.3 % for the same process parameters. Especially for process parameters that produce parts with lower relative densities, vibrations have an influence on part density. With an increase in part density, this effect gets less pronounced.Item Variability in the Geometric Accuracy of Additively Manufactured Test Parts(University of Texas at Austin, 2010) Cooke, A.L.; Soons, J.A.This paper describes the results of a study on the variability in the geometric accuracy of a metal test part manufactured by several service providers using either an electron beam or laser beam powder bed thermal fusion process. The part was a circle-diamond-square test part with an inverted cone that is used to evaluate the performance of five-axis milling machines. The study was conducted to aid development of standardized parameters and test methods to specify and evaluate the performance of additive manufacturing systems. Without standards for performance characterization, it is difficult to match system capabilities with part requirements and ensure consistent and predictable part quality across systems, operators, and manufacturing facilities.