FUNDAMENTALS OF MATERIAL REMOVAL IN SILICON CARBIDE FOR FREEFORM OPTICS

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Shanmugam, P. (2019). FUNDAMENTALS OF MATERIAL REMOVAL IN SILICON CARBIDE FOR FREEFORM OPTICS. Unc Charlotte Electronic Theses And Dissertations.
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Abstract

The mechanical and thermal properties offered by Silicon carbide (SiC) make it an ideal material for reflective freeform optics. However, the hardness, brittleness and fracture toughness of the material pose a challenge to manufacturing. The manufacturing process must attain the desired surface finish and form tolerances with the least possible subsurface damage. From the optical fabrication standpoint, two out of the three above-mentioned surface response behaviors are studied in this thesis; surface roughness and subsurface damage. The goal of this research is to grind different grades of SiC under identical sets of parametric conditions and study the surface and subsurface response behaviors. Five different grades of SiC were procured from different suppliers and were ground under identical conditions on a Makino A55 machining center and on an Optisonic 1250x grinding machine with different grinding configurations. The subsurface damage was studied using a recently developed method called MRF spotting. The results of this study add to existing literature on the understanding of the process mechanics in grinding SiC and allow for more effective selection of process parameters to efficiently grind SiC optics while maintaining surface and subsurface integrity. The thesis analyzes the surface mechanics and provides a baseline understanding of the effect of process parameters on surface roughness and subsurface damage. The thesis concludes with preliminary tests conducted to understand surface mechanics in grinding complex optics, starting with test spheres ground with cup grinding wheels.

Details
Author

Shanmugam, Prithiviraj

Title

FUNDAMENTALS OF MATERIAL REMOVAL IN SILICON CARBIDE FOR FREEFORM OPTICS

Physical Description

1 online resource (170 pages) : PDF

Date

2019

Degree Granting Institution

University of North Carolina at Charlotte

Abstract

The mechanical and thermal properties offered by Silicon carbide (SiC) make it an ideal material for reflective freeform optics. However, the hardness, brittleness and fracture toughness of the material pose a challenge to manufacturing. The manufacturing process must attain the desired surface finish and form tolerances with the least possible subsurface damage. From the optical fabrication standpoint, two out of the three above-mentioned surface response behaviors are studied in this thesis; surface roughness and subsurface damage. The goal of this research is to grind different grades of SiC under identical sets of parametric conditions and study the surface and subsurface response behaviors. Five different grades of SiC were procured from different suppliers and were ground under identical conditions on a Makino A55 machining center and on an Optisonic 1250x grinding machine with different grinding configurations. The subsurface damage was studied using a recently developed method called MRF spotting. The results of this study add to existing literature on the understanding of the process mechanics in grinding SiC and allow for more effective selection of process parameters to efficiently grind SiC optics while maintaining surface and subsurface integrity. The thesis analyzes the surface mechanics and provides a baseline understanding of the effect of process parameters on surface roughness and subsurface damage. The thesis concludes with preliminary tests conducted to understand surface mechanics in grinding complex optics, starting with test spheres ground with cup grinding wheels.

Genre

masters theses

Subjects--Topics

Mechanical engineering

Degree

M.S.

Keywords

Diamond Grinding
MRF Polishing
Optical Fabrication
Silicon Carbide
Subsurface Damage

Subject Area

Mechanical Engineering

Advisor(s)

Davies, Matthew

Committee Members

Evans, Christopher
Owen, Joseph
Suleski, Thomas

Degree Note

Thesis (M.S.)--University of North Carolina at Charlotte, 2019.

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Rights Holder Information

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Identifier

Shanmugam_uncc_0694N_12089

Permalink

http://hdl.handle.net/20.500.13093/etd:2088