Surface Modeling And Scatter Analysis For Diamond Turned Aluminum Mirror

Diamond turned mirror is widely applied in frontier field of laser mirror and tele-scope etc. Its image quality has significant impact on total system. Light scatter existswidely on the ultra-precision machining surfaces and remarkably affects mirror imagequality. It has great theoretical and practical significance to study the parameters whichcan affect mirror image quality and find methods to reduce scattering and improve imagequality. In this paper theoretical and technical research is conducted for this target.Firstly, combining with tool trace analysis and two-dimensional topography model-ing theory, three-dimensional topography model based on minimum uncut chip thicknesson the condition of no vibration and vibration is set up. The model is verified throughthe AFM measurement result. A simulation software is developed and researches of vi-bration is conducted with it. Simulation results reveal the characters of vibration effecton the surface topography and roughness. In addition, PSD analysis on3D topography ofworkpiece is conducted. Conclusion that the PSD distribution of lower scatter mirror isconcentrated and its value is large can be drawn.Secondly, modeling and analysis of scatter based on Fourier optics theory is carriedon. Characters of reflection on the metal surface are analyzed with the Maxwell equationgroup. Comparing with different materials, one can conclude that aluminum alloy issuitable for mirror manufacturing. By calculating the distribution of specular light onreceive screen, the parameters that affect specular light power are found out. Feasiblemeasures that reducing surface roughness and adding the angle of incidence are proposed.Finally, technical and optical experiments are conducted. Using neural network al-gorithm, a mathematical model between surface roughness and machining parameters isset up. With the help of Simulated annealing algorithm and particle swarm optimization,the process parameters is obtained in which the surface roughness is minimum in actualconditions. Optical experiments with the workpiece that machining on this parameters isconducted. The results prove the rationality of the optical model.