dc.contributor.author |
Tonnellier, Xavier |
- |
dc.contributor.author |
Shore, Paul |
- |
dc.contributor.author |
Morantz, Paul |
- |
dc.contributor.author |
Baldwin, A. |
- |
dc.contributor.author |
Walker, D. |
- |
dc.contributor.author |
Yu, G. |
- |
dc.contributor.author |
Evans, R. |
- |
dc.date.accessioned |
2012-07-10T23:00:36Z |
|
dc.date.available |
2012-07-10T23:00:36Z |
|
dc.date.issued |
2008-07-14T00:00:00Z |
- |
dc.identifier.citation |
Tonnellier X, Shore P, Morantz P, et al., (2008) Sub-surface damage issues for effective fabrication of large optics.
Proceedings of SPIE Advanced Optical and Mechanical Technologies in Telescopes and Instrumentation, 23 June 2008, Marseille, France. Volume 7018 |
|
dc.identifier.isbn |
978-081947228-1 |
- |
dc.identifier.uri |
http://dx.doi.org/10.1117/12.790639 |
- |
dc.identifier.uri |
http://dspace.lib.cranfield.ac.uk/handle/1826/7364 |
|
dc.description.abstract |
A new ultra precision large optics grinding machine, BoX®has been developed at
Cranfield University. BoX®islocated at the UK's Ultra Precision Surfaces
laboratory at the OpTIC Technium. This machine offers a rapidand 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 usingdiamond resin bonded grinding wheels. The
specific materials used, Zerodur®and ULE®are currently understudy 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 of76 μm, 46 μm and 25 μm. Grinding process data
was collected using a Kistler dynamometer platform. Thehighest material removal
rate (187.5 mm3/s) used ensures that a 1 metre diameter optic can be ground in
lessthan 10 hours. The surface roughness and surface profile were measured using
a Form Talysurf. The subsurfacedamage 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 roughnessof 50-150 nm RMS and subsurface damage in the range of 2-5 μm.
This process stage was validated on a 400mm ULE®blank and a 1 metre hexagonal Ze |
en_UK |
dc.language.iso |
en_UK |
- |
dc.title |
Sub-surface damage issues for effective fabrication of large optics |
en_UK |
dc.type |
Conference paper |
- |