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Proceedings Paper • Open Access

ELID grinding of SiC ultra lightweight mirror
Author(s): Hiroaki Eto; Yutang Dai; Noboru Ebizuka; Yasutaka Saito; Toru Suzuki; Weimin Lin; Hitoshi Ohmori; Toshikazu Ebisuzaki; Hideki Takami

Paper Abstract

Silicon carbide (SiC) is the most advantageous as the material of various telescope mirrors, because SiC has high stiffness, high thermal conductivity, low thermal expansion and low density and so on [1] [2]. However, since SiC is very hard, it is difficult to obtain the surfaces efficiently by using ordinary grinding method. Therefore, we developed the ultra lightweight mirror by ELID (ELectrolytic In-process Dressing) grinding method and ultra-precision grinding machine.

ELID grinding method is the new grinding technology which one of authors invented, produces the quality of the high surface efficiently, and is effective in processing of a very hard material, such as crystalline silicon and sapphire, ceramics, glasses, hard metals and so on. SiC mirror for space telescope is designed as regular polygon rib structures in the rear face for reducing weight, and both the optical face and the backside ribs are so thin that deformation of the mirror cannot disregard. Therefore, in order to feed back deformation of the mirror to the orbit of grinding wheel, it is necessary to analyze deformation.

In this research, we present the results which fabricated mirrors of sintered SiC by the ELID grinding method, the numerical calculation results of the profile deformations analyzed by FEM, and new jig for Φ360mm a mirror.

Paper Details

Date Published: 21 November 2017
PDF: 5 pages
Proc. SPIE 10568, International Conference on Space Optics — ICSO 2004, 105681I (21 November 2017); doi: 10.1117/12.2308013
Show Author Affiliations
Hiroaki Eto, RIKEN (Japan)
Yutang Dai, RIKEN (Japan)
Noboru Ebizuka, RIKEN (Japan)
Yasutaka Saito, RIKEN (Japan)
Toru Suzuki, RIKEN (Japan)
Weimin Lin, RIKEN (Japan)
Hitoshi Ohmori, RIKEN (Japan)
Toshikazu Ebisuzaki, RIKEN (Japan)
Hideki Takami, National Astronomical Observatory of Japan (Japan)

Published in SPIE Proceedings Vol. 10568:
International Conference on Space Optics — ICSO 2004
Josiane Costeraste; Errico Armandillo, Editor(s)

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