
Proceedings Paper
Precision grinding for rapid fabrication of segments for extremely large telescopes using the Cranfield BoXFormat | Member Price | Non-Member Price |
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Paper Abstract
An ultra precision large optics grinding machine, BoX®, was developed and produced at Cranfield University. BoX®
offers a rapid and economic solution for grinding large off-axis aspherical and free-form optical components. Grinding
high accuracy surfaces with low subsurface damage reduces subsequent polishing time. This efficient grinding process
provides the capacity to grind 1.5 m parts. This paper presents an analysis of Astrositall® optical ground parts: a
hexagonal 84 m radius of curvature mirror of 1 m across corners and an off-axis 350 mm diameter mirror. The 1 m
hexagonal part is representative of segments under study for making extremely large telescope (ELT) segmented mirrors.
The second part was machined off-axis to demonstrate free-form fabrication capability. These operations demonstrate
the scalability of the rapid grinding process developed for large free-form optics. The use of an error compensation
procedure improved an initial ground form accuracy to +/- 1 μm p-v over 1 metre surface. The results highlighted the
effect of grinding parameters and machine dynamics on form accuracy and fabrication time.
Paper Details
Date Published: 19 July 2010
PDF: 8 pages
Proc. SPIE 7739, Modern Technologies in Space- and Ground-based Telescopes and Instrumentation, 773905 (19 July 2010); doi: 10.1117/12.858806
Published in SPIE Proceedings Vol. 7739:
Modern Technologies in Space- and Ground-based Telescopes and Instrumentation
Eli Atad-Ettedgui; Dietrich Lemke, Editor(s)
PDF: 8 pages
Proc. SPIE 7739, Modern Technologies in Space- and Ground-based Telescopes and Instrumentation, 773905 (19 July 2010); doi: 10.1117/12.858806
Show Author Affiliations
Published in SPIE Proceedings Vol. 7739:
Modern Technologies in Space- and Ground-based Telescopes and Instrumentation
Eli Atad-Ettedgui; Dietrich Lemke, Editor(s)
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