1999 / Solid Freeform Fabrication Proceedings
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Author K. Williams, N. Jaikumar, G. Saiprasanna, M. Hegler, J. Maxwell, Louisiana Tech University
Source Solid Freeform Fabrication Proceedings, 1999, pp 543-552
Abstract This paper reports the development of a two-beam Laser Microchemical Lathe (LML) used for prototyping freeform axi-symmetric parts from the vapor phase. In the LML, one beam is focused along the rotational axis of the lathe, while another is scanned at right angles to the first. The first beam is used for alignment and to deposit a fiber-like mandrel from a vapor-phase precursor. The second beam is then applied to add or remove material on this rotating mandrel, either through high pressure laser chemical vapor deposition (LCVD) or laser chemical vapor etching (LCVE). Material is added when an appropriate precursor is present, or removed when a reducing atmosphere such as chlorine, iodine, or hydrogen is employed. In LCVE mode, the second beam may be scanned in profile along the length of a rotating part-thereby profiling the part by laser etching. The ability to correct for errors in the deposition process through such laser profiling allows accurate prototyping of milli-scale axi-symmetric parts , such as lead screws, cams, and sharp needles. Very rapid deposition and etching rates were achieved; at ethylene pressures above 10 atmospheres, diamond-like carbon was grown at linear rates exceeding 120,000 microns per second (12 cm/s). This record- setting growth rate allows the computer-controlled prototyping of carbon-fiber reinforced structures with volumes surpassing 1 cubic centimeter in only 10-20 minutes. Keywords: High Pressure Laser Chemical Vapor Deposition, Carbon, Alkenes, Direct-writing, Freeform Growth. (Auth abstract) [References: 14]
Solid Freeform Fabrication Proceedings can be obtained from: The Solid Freeform Fabrication Symposium
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The University of Texas at Austin
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Mechanical Engineering Dept.
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MC C2200
Austin, TX 78712-1063 USA
512-471-3026; 512-471-7681 FX; Email: sffsymp@uts.cc.utexas.edu