Sub-surface damage issues for effective fabrication of large optics
| 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.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.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.language.iso | en_UK | - |
| dc.title | Sub-surface damage issues for effective fabrication of large optics | en_UK |
| dc.type | Conference paper | - |