Sub-surface damage issues for effective fabrication of large optics

Details Sub-surface damage issues for effective fabrication of large optics Sub-surface damage issues for effective fabrication of large optics

Jul 2008

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008spie.7018e..12t&link_type=abstract

Advanced Optical and Mechanical Technologies in Telescopes and Instrumentation. Edited by Atad-Ettedgui, Eli; Lemke, Dietrich.

Physics

Optics

Scientific paper

A new ultra precision large optics grinding machine, BoX® has been developed at Cranfield University. BoX® is located at the UK's Ultra Precision Surfaces laboratory at the OpTIC Technium. This machine offers a rapid and economic solution for grinding large off-axis aspherical and free-form optical components. This paper presents an analysis of subsurface damage assessments of optical ground materials produced using diamond resin bonded grinding wheels. The specific materials used, Zerodur® and ULE® are currently under study for making extremely large telescope (ELT) segmented mirrors such as in the E-ELT project. The grinding experiments have been conducted on the BoX® grinding machine using wheels with grits sizes of 76 μm, 46 μm and 25 μm. Grinding process data was collected using a Kistler dynamometer platform. The highest material removal rate (187.5 mm3/s) used ensures that a 1 metre diameter optic can be ground in less than 10 hours. The surface roughness and surface profile were measured using a Form Talysurf. The subsurface damage was revealed using a sub aperture polishing process in combination with an etching technique. These results are compared with the targeted form accuracy of 1 μm p-v over a 1 metre part, surface roughness of 50-150 nm RMS and subsurface damage in the range of 2-5 μm. This process stage was validated on a 400 mm ULE® blank and a 1 metre hexagonal Zerodur® part.

Affiliated with

Also associated with

No associations

Rating

Sub-surface damage issues for effective fabrication of large optics does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Sub-surface damage issues for effective fabrication of large optics, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Sub-surface damage issues for effective fabrication of large optics will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-794357