Open AccessEdges in CNC polishing: from mirror-segments towards semiconductors, paper 1: edges on processing the global surface
Author(s) -
David D. Walker,
Guoyu Yu,
Hongyu Li,
Wilhelmus A. C. M. Messelink,
RA Evans,
Anthony Beaucamp
Publication year - 2012
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.20.019787
Subject(s) - polishing , optics , telescope , enhanced data rates for gsm evolution , surface (topology) , computer science , materials science , physics , mechanical engineering , engineering , telecommunications , geometry , mathematics
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.