Dissertation > Excellent graduate degree dissertation topics show

The Research on Surface Quality of KDP Crystal Machined by Single Point Diamond Turning

Author: LiZhenXing
Tutor: WangJingHe
School: Harbin Institute of Technology
Course: Mechanical Manufacturing and Automation
Keywords: Surface characteristics Metamorphic layer Subsurface damage Cutting simulation
CLC: O786
Type: Master's thesis
Year: 2008
Downloads: 58
Quote: 0
Read: Download Dissertation

Abstract

KDP (Potassium Dihydrogen Phosphate) crystal is used as an excellent nonlinear optical material, is widely used in the field of laser and nonlinear optics. KDP crystals, processed, due to the combined effect of the mechanical and thermal processing, the nature of the surface changed a lot, there are a lot of cracks, scratches, pits KDP crystal structure damage mostly from the surface start to the range of tens of microns below the surface the physical and mechanical properties change under the surface of the surface of the optical elements of the laser damage threshold a great impact, it has become the inertial confinement fusion (ICF) laser driver development bottlenecks . But the machined surface characteristics of the KDP crystal is quite limited, so this project will have a brittle material KDP crystal single point diamond cutting surface characteristics - metamorphic layer and subsurface damage. In order to optimize the process parameters to control the quality of the machined surface, thereby increasing the laser. This is of great significance for our large aperture optics engineering manufacturing, as well as the entire laser device developed. First, quadratic regression general rotation law the design cutting experiments machining KDP crystal, the the hardness indentation experiments - depth curve to estimate the the metamorphic layer thickness, the the metamorphic layer thickness and cutting parameters regression equation. The analysis of the equation to get: the the metamorphic layer thickness in descending order as cutting speed of cut and feed rate back to eat; within a certain range, the metamorphic layer thickness increase of cutting the amount of increase. Secondly, based on the fracture mechanics of materials, surface roughness (SR) and subsurface damage (SSD) depth of the relationship, to obtain a non-injury KDP crystal subsurface damage depth measurement method. And white light interferometer measurement KDP crystal subsurface damage depth, density and cutting parameters regression equation, we can see through the equation: cutting speed, cutting depth is a major factor in the formation of subsurface damage; and subsurface damage The depth and density with the cutting depth increases, but the cutting speed is increased to cause damage density increases, but the depth is reduced. Finally, using the the Marc nonlinear finite element software to simulate the cutting process of KDP crystal, through the analysis of different cutting speed, stress and strain in the process of cut back eating found: processed KDP crystal surface tensile stress; and stress and strain as the back to eat knife increase in the amount increases, and decreases with increasing cutting speed, and thus on the front side to make conclusions about the the metamorphic layer thickness and depth of subsurface damage, density from The angle of the stress and strain to explain.

Related Dissertations

CLC: > Mathematical sciences and chemical > Crystallography > Crystal growth > Crystal processing
© 2012 www.DissertationTopic.Net Mobile