Development of hybrid "fluid jet / float" polishing process

Anthony T.H. Beaucamp, Yoshiharu Namba, Richard R. Freeman

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Citations (Scopus)


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.

Original languageEnglish
Title of host publicationOptical Manufacturing and Testing X
Publication statusPublished - 2013
Externally publishedYes
EventOptical Manufacturing and Testing X - San Diego, CA, United States
Duration: 2013 Aug 262013 Aug 27

Publication series

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


ConferenceOptical Manufacturing and Testing X
Country/TerritoryUnited States
CitySan Diego, CA


  • Finishing
  • Float Polishing
  • Fluid Jet Polishing
  • Gamma Ray
  • Hybrid Process
  • Optics
  • Ultra-Precision
  • X-ray

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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