Automated optical fabrication: First results from the new "Precessions" 1.2m CNC polishing machine

D. D. Walker, A. T.H. Beaucamp, V. Doubrovski, C. Dunn, R. Evans, R. Freeman, J. Kelchner, G. McCavana, R. Morton, D. Riley, J. Simms, G. Yu, X. Wei

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

29 Citations (Scopus)


The requirements of space and defence optical systems and ground-based astronomy (especially extremely large telescopes) are providing optical fabricators with new challenges. These challenges particularly concern process speed, determinism and automation, and tighter tolerances on surface form and texture. Moreover, there is a growing demand for complex off-axis and 'freeform' surfaces and for larger components of the ~lm scale. With this in view, we first report on form-correction on a smaller analogue of the LRP1200 - an IRP400 in service in industry. We then report on the design, commissioning and preliminary process-development results from the first of the scaled-up 1.2m capacity CNC polishing machine from Zeeko, Ltd. This machine delivers the 'Classic' bonnet-based process, together with two new processes - fluid-jet polishing and the hybrid soft-grinding/polishing process called 'Zeeko-Grolish.' We indicate how this trio of processes running on the same machine platform with unified software can provide an unprecedented dynamic range in both volumetric removal rate and removal spot-size. This leads into a discussion of how these processes may be brought to bear on optimal control of texture and form. Preliminary performance of the 1.2m machine is illustrated with results on both axially-symmetric and more complex removal regimes. The paper concludes with an overview of the relevance of the technology to efficient production of instrumentation-optics, space optics and segmented telescope mirrors.

Original languageEnglish
Title of host publicationOptomechanical Technologies for Astronomy
EditorsEli Atad-Ettedgui, Joseph Antebi, Dietrich Lemke
Number of pages8
ISBN (Print)9780819463388
Publication statusPublished - 27 Jul 2006
Externally publishedYes
EventSPIE Astronomical Telescopes + Instrumentation - Orlando, United States
Duration: 24 May 200631 May 2006

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceSPIE Astronomical Telescopes + Instrumentation
Country/TerritoryUnited States


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