
Proceedings Paper
Development of hybrid fluid jet/float polishing processFormat | Member Price | Non-Member Price |
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Paper Abstract
On one hand, the “float polishing” process consists of a tin lap having many concentric grooves, cut from a flat by single
point diamond turning. This lap is rotated above a hydrostatic bearing spindle of high rigidity, damping and rotational
accuracy. The optical surface thus floats above a thin layer of abrasive particles. But whilst surface texture can be
smoothed to ~0.1nm rms (as measured by atomic force microscopy), this process can only be used on flat surfaces. On
the other hand, the CNC “fluid jet polishing” process consists of pumping a mixture of water and abrasive particles to a
converging nozzle, thus generating a polishing spot that can be moved along a tool path with tight track spacing. But
whilst tool path feed can be moderated to ultra-precisely correct form error on freeform optical surfaces, surface finish
improvement is generally limited to ~1.5nm rms (with fine abrasives). This paper reports on the development of a novel
finishing method, that combines the advantages of “fluid jet polishing” (i.e. freeform corrective capability) with “float
polishing” (i.e. super-smooth surface finish of 0.1nm rms or less). To come up with this new “hybrid” method,
computational fluid dynamic modeling of both processes in COMSOL is being used to characterize abrasion conditions
and adapt the process parameters of experimental fluid jet polishing equipment, including: (1) geometrical shape of
nozzle, (2) position relative to the surface, (3) control of inlet pressure. This new process is aimed at finishing of next
generation X-Ray / Gamma Ray focusing optics.
Paper Details
Date Published: 7 September 2013
PDF: 7 pages
Proc. SPIE 8838, Optical Manufacturing and Testing X, 88380P (7 September 2013); doi: 10.1117/12.2023919
Published in SPIE Proceedings Vol. 8838:
Optical Manufacturing and Testing X
Oliver W. Fähnle; Ray Williamson; Dae Wook Kim, Editor(s)
PDF: 7 pages
Proc. SPIE 8838, Optical Manufacturing and Testing X, 88380P (7 September 2013); doi: 10.1117/12.2023919
Show Author Affiliations
Richard R. Freeman, Zeeko Ltd. (United Kingdom)
Published in SPIE Proceedings Vol. 8838:
Optical Manufacturing and Testing X
Oliver W. Fähnle; Ray Williamson; Dae Wook Kim, Editor(s)
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