@inproceedings{00f2dec452a64c4dac5ae2ef87cc7d84,
title = "New Results from the Precessions Polishing Process Scaled to Larger Sizes",
abstract = "The Precessions process uses an inflated membrane-tool that delivers near-Gaussian polishing spots. The tool-motion over the part can be constructed to preserve an aspheric form whilst removing damage from preceding processes, or control the form through a tool-path prescribed by numerical optimization. The process has previously been validated on surfaces up to 200mm diameter and used extensively in industrial environments. In this paper we report the first trials on a substantially larger part - a 500mm diameter f/1 ellipsoidal mirror - as part of the UK's technology-development for Extremely Large Telescopes. We draw attention to subtle problems that have arisen along the way. We also report on developing the process for free-form surfaces, in contrast to the axially-symmetric parts worked hitherto. The paper concludes with an assessment of the lessons learnt from the experiments, as they may impact on realization in a practical ELT segment fabrication facility.",
keywords = "Polishing, Surface finishing, Metrology, Mirrors, Optical Spheres, Aspheric lenses, Distortion, Interferometry, Spatial frequencies",
author = "Walker, {D. D.} and Beaucamp, {A. T.H.} and D. Brooks and V. Doubrovski and M. Cassie and C. Dunn and R. Freeman and A. King and M. Libert and G. McCavana and R. Morton and D. Riley and J. Simms",
year = "2004",
month = sep,
day = "24",
doi = "10.1117/12.553044",
language = "English",
isbn = "9780819454263",
volume = "5494",
series = "Proceedings of SPIE - The International Society for Optical Engineering",
publisher = "SPIE",
pages = "71--80",
editor = "Eli Atad-Ettedgui and Philippe Dierickx",
booktitle = "Optical Fabrication, Metrology, and Material Advancements for Telescopes",
address = "United States",
note = "SPIE Astronomical Telescopes + Instrumentation ; Conference date: 21-06-2004 Through 25-06-2004",
}