Characterization of Optical Surface Grinding using Bound and Loose Abrasives

Persistent Link:
http://hdl.handle.net/10150/203478
Title:
Characterization of Optical Surface Grinding using Bound and Loose Abrasives
Author:
Johnson, James Ballard
Issue Date:
2011
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Large optical systems fabrication is a demanding task due to the tight requirements and big scales. To make mirrors up to 8.4m in diameter necessitates technological development in materials, tooling, and metrology. These advancements are designed to not only produce optics on a near-unheard of scale, but to improve fabrication methods with each piece.For an optical surface to be properly polished, the amount of material removed during polishing must be greater than the volume of damage left behind by the grinding process. Mixed-mode grinding, which combines bound abrasives with a compliant binder material, is a valuable tool at this stage as it creates less damage while maintaining a fast and uniform cutting rate than traditional loose abrasive grinding.These materials are challenging for large optical surfaces due to the honeycomb structures used to lightweight the mirrors. Development is done to adapt the abrasive to handle the very low pressures and speeds required to avoid imprinting structure on the optical surface.We take a comprehensive approach in measuring mixed-mode behavior using 3M Trizact™. Prior works on bound abrasives have focused on specific properties: removal rates, subsurface damage, etc. None have yet to look at the entire scope of the material and its benefits. These properties will be analyzed along with different behaviors regarding surface scattering, Twyman effect bending moments, glazing, manufacturing expenses, and failure mechanisms. This comprehensive understanding of the abrasive allows manufacturers to create better grinding schedules and reduce overall expenses in fabrication.Trizact shows up to a three times faster removal rate while producing 30\% less subsurface damage than loose abrasives of similar size. Additionally, the surface has scatters less light which can be adapted through changes in processing to create a specular reflection for optical surface metrology.Based on our findings, this type of abrasive integrates into current optical fabrication processes as a pre-polishing material. Here, the transition to these abrasives becomes cost effective by rapidly eliminating damage created during the generating of the surface and reducing the amount of polishing required.
Type:
text; Electronic Dissertation
Keywords:
subsurface damage; Twyman effect; Optical Sciences; grinding; optical fabrication
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Optical Sciences
Degree Grantor:
University of Arizona
Advisor:
Burge, James H.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleCharacterization of Optical Surface Grinding using Bound and Loose Abrasivesen_US
dc.creatorJohnson, James Ballarden_US
dc.contributor.authorJohnson, James Ballarden_US
dc.date.issued2011-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractLarge optical systems fabrication is a demanding task due to the tight requirements and big scales. To make mirrors up to 8.4m in diameter necessitates technological development in materials, tooling, and metrology. These advancements are designed to not only produce optics on a near-unheard of scale, but to improve fabrication methods with each piece.For an optical surface to be properly polished, the amount of material removed during polishing must be greater than the volume of damage left behind by the grinding process. Mixed-mode grinding, which combines bound abrasives with a compliant binder material, is a valuable tool at this stage as it creates less damage while maintaining a fast and uniform cutting rate than traditional loose abrasive grinding.These materials are challenging for large optical surfaces due to the honeycomb structures used to lightweight the mirrors. Development is done to adapt the abrasive to handle the very low pressures and speeds required to avoid imprinting structure on the optical surface.We take a comprehensive approach in measuring mixed-mode behavior using 3M Trizact™. Prior works on bound abrasives have focused on specific properties: removal rates, subsurface damage, etc. None have yet to look at the entire scope of the material and its benefits. These properties will be analyzed along with different behaviors regarding surface scattering, Twyman effect bending moments, glazing, manufacturing expenses, and failure mechanisms. This comprehensive understanding of the abrasive allows manufacturers to create better grinding schedules and reduce overall expenses in fabrication.Trizact shows up to a three times faster removal rate while producing 30\% less subsurface damage than loose abrasives of similar size. Additionally, the surface has scatters less light which can be adapted through changes in processing to create a specular reflection for optical surface metrology.Based on our findings, this type of abrasive integrates into current optical fabrication processes as a pre-polishing material. Here, the transition to these abrasives becomes cost effective by rapidly eliminating damage created during the generating of the surface and reducing the amount of polishing required.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectsubsurface damageen_US
dc.subjectTwyman effecten_US
dc.subjectOptical Sciencesen_US
dc.subjectgrindingen_US
dc.subjectoptical fabricationen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineOptical Sciencesen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorBurge, James H.en_US
dc.contributor.committeememberParks, Robert E.en_US
dc.contributor.committeememberSasian, Jose M.en_US
dc.contributor.committeememberBurge, James H.en_US
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