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Research On Ultraprecise And Low-damage Cerium Grinding On Optical Glass Pieces

Posted on:2014-04-27Degree:MasterType:Thesis
Country:ChinaCandidate:Y F ZhangFull Text:PDF
GTID:2272330479979109Subject:Mechanical engineering
Abstract/Summary:PDF Full Text Request
In order to develop new energy and make nuclear fusion energy in control, some countries conduct researches on Inertial Confinement Fusion. The ICF device contains massive inner optical glass pieces and the performance improvement of ICF device is stopped by the precision and defect of optical glass pieces. It is revealed that the damage threshold of optical glass pieces has direct relationship with their surface defect and subsurface defect, which means the fewer the defects are, the smaller the energy concentration effect is and the higher the damage threshold is. Thus researchers are looking for ways to optimize machining process so as to diminish surface defects and subsurface defects of optical pieces and then improve ICF device’s performance as much as possible.Recently the cerium dioxide grinding process is used in single crystal silicon wafers machining in IC field, which can diminish defects and have machining stress in control, while on optical glass pieces few researches are conducted. Whether this process can be used in optical glass machining and enhance the optical pieces’ anti-laser damage threshold requires researchers to further understand the material removal mechanism of cerium grinding, build force model and thermal model of grinding, design proper process, and realize the purpose of reducing optical pieces’ surface defects and subsurface defects. Therefore the work in this paper is very important to contribute to improve the quality and efficiency in the machining of glass pieces in ICF device. The paper mainly contains the following work.1) Research on the material removal mechanism of cerium dioxide grinding. Based on the mechanical and chemistry effect during the cerium dioxide grinding, this part mainly discusses possible chemistry reactions under high temperature during the grinding process, and analyzes how the affected layer is formed by these reactions, how the affected layer can reduce material removal resistance and residual stress, and how it can diminish those defects.2) Building the force model and temperature model during grinding process. Based on parallel grinding model, according to a optimized method this part builds the force model of cerium dioxide wheel grinding, which considers process factors like cutting depth, linear speed of wheel and moving speed of pieces. The force model is tested in a series of grinding force measurements. And meanwhile, by means of thermodynamics and principle of energy conservation, this paper builds the temperature model, discusses impacts by cutting depth, linear speed of wheel, moving speed of pieces and cooling conditions, and estimates the grinding temperature under different processes.3) Optimizing the cerium dioxide grinding process. The part conducts grinding experiments of three kinds of cerium dioxide wheels. The trials reveal some characteristics and problems of cerium dioxide wheel grinding, such as easy to burn and wear. This part makes efforts to optimize process to realize nanometer machining, conducts research on surface damage and subsurface damage by cerium dioxide grinding in contrast to the traditional polishing process and magneto-rheological process, and works on the critical removal time horizon of fragile cracks by grinding and the impacts on surface damage or surface roughness by wheel burning.It requires further research on the cerium dioxide grinding, especially on the material removal mechanism and ultraprecise grinding process which needs new ways and methods, and helps solve engineering problems like laser damage.
Keywords/Search Tags:cerium dioxide grinding, low damage, subsurface damage, ultraprecise machining
PDF Full Text Request
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