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Proceedings Paper

Rapid cost-effective silicon carbide optical component manufacturing technique
Author(s): John M. Casstevens; Ronald Plummer; Jim Jarocki
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Paper Abstract

Silicon carbide may well be the best known material for the manufacture of high performance optical components. A combination of extremely high specific stiffness (r/E), high thermal conductivity and outstanding dimensional stability make silicon carbide superior overall to beryllium and low- expansion glass ceramics. A major impediment to wide use of silicon carbide in optical systems has been the costs of preliminary pressing, casting, shaping and final finishing of silicon carbide. Diamond grinding of silicon carbide is a slow and expensive process even on machines specially designed for the task. The process described here begins by machining the component from a special type of graphite. This graphite is easily machined with multi-axis CNC machine tools to any level of complexity and lightweighting required. The graphite is then converted completely to silicon carbide with very small and very predictable dimensional change. After conversion to silicon carbide the optical surface is coated with very fine grain silicon carbide which is easily polished to extreme smoothness using conventional optical polishing techniques. The fabrication process and a 6 inch diameter development mirror is described.

Paper Details

Date Published: 29 October 1999
PDF: 7 pages
Proc. SPIE 3785, Advanced Telescope Design, Fabrication, and Control, (29 October 1999); doi: 10.1117/12.367617
Show Author Affiliations
John M. Casstevens, Dallas Optical Systems, Inc. (United States)
Ronald Plummer, Poco Graphite, Inc. (United States)
Jim Jarocki, Poco Graphite, Inc. (United States)

Published in SPIE Proceedings Vol. 3785:
Advanced Telescope Design, Fabrication, and Control
William Roybal, Editor(s)

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