Edges in CNC polishing: From mirror-segments towards semiconductors, paper 1: Edges on processing the global surface

David Walker, Guoyu Yu, Hongyu Li, Wilhelmus Messelink, Rob Evans, Anthony Beaucamp

Research output: Contribution to journalArticle

49 Citations (Scopus)


Segment-edges for extremely large telescopes are critical for observations requiring high contrast and SNR, e.g. detecting exo-planets. In parallel, industrial requirements for edge-control are emerging in several applications. This paper reports on a new approach, where edges are controlled throughout polishing of the entire surface of a part, which has been pre-machined to its final external dimensions. The method deploys compliant bonnets delivering influence functions of variable diameter, complemented by small pitch tools sized to accommodate aspheric mis-fit. We describe results on witness hexagons in preparation for full size prototype segments for the European Extremely Large Telescope, and comment on wider applications of the technology.

Original languageEnglish
Pages (from-to)19787-19798
Number of pages12
JournalOptics Express
Issue number18
Publication statusPublished - 27 Aug 2012
Externally publishedYes


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