大口径非球面SiC反射镜磨削工艺优化

发布时间：2018-01-30 05:16

本文关键词： 大口径SiC反射镜工艺优化面形误差亚表面损伤磨削效率　出处：《哈尔滨工业大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着人类对太空的探索,对观测设备的成像性能要求越来越高。基于反应烧结SiC陶瓷材料的良好特性,现在已经成为主反射镜的首选材料。SiC反射镜的镜面形状和尺寸决定了观测设备的成像质量。故制造大口径SiC非球面反射镜和提高反射镜的形状精度是改善成像质量的重要途径。大口径反射镜的磨削加工效率低,砂轮磨损严重,非球面面形较差,镜坯亚表面损伤严重。故提高非球面面形精度,降低非球面亚表面损伤以及提高磨削效率具有重要意义。本文针对大口径SiC非球面反射镜磨削加工过程进行优化,改善面形,减少损伤,并提高效率。在圆弧砂轮以螺旋式运动轨迹加工非球面工件时,在母线方向建立了考虑砂轮径向磨损量的残余高度模型,在此基础上建立了面形误差模型,分析了各工艺参数对面形误差的影响规律,进行了圆弧砂轮磨削非球面反射镜实验,验证了面形误差模型的正确性,并使用修正系数对模型进行了修正;为了推导砂轮径向磨损,进行了磨削比实验研究,建立了磨削比回归方程。面形误差模型的建立为磨削工艺优化提供理论基础。通过反应烧结SiC陶瓷平面磨削实验,研究了磨削加工后SiC陶瓷的表面/亚表面质量。研究了不同工艺参数下SiC陶瓷的亚表面裂纹深度、表面破碎层深度以及材料的去除机理,并对不同参数下的表面质量进行了对比分析,分析了工艺参数对亚表面裂纹深度、表面破碎层深度以及表面粗糙度的影响规律;实现了工艺参数的优化,得到了参数最优解。亚表面损伤的研究及工艺参数的优化为磨削加工参数的选择奠定了理论基础。提出了大口径反射镜的磨削加工工艺的优化策略,包括磨削方式的分析与选择,砂轮运动轨迹的分析与选择,基于砂轮磨损的面形误差补偿模型的建立,基于改变进给速度的等残余高度优化,磨削层厚度的分析与选择,磨削效率的分析与计算;通过工艺优化策略,实现了大口径SiC反射镜磨削加工工艺的优化,对比分析了优化与正常加工下的面形误差与磨削加工效率,改善了非球面的面形精度,降低了亚表面损伤深度,提高了加工效率。最终形成了适合于大口径反射镜磨削加工的优化策略。
[Abstract]:With the exploration of space, the imaging performance of observation equipment is becoming more and more high. Based on the good characteristics of reactive sintering SiC ceramic materials. The shape and size of sic mirror, which has become the preferred material for the main mirror, determines the imaging quality of the observation equipment. Therefore, the shape accuracy of the large aperture SiC aspheric mirror and the improvement of the shape accuracy of the mirror are obtained. The grinding efficiency of large aperture mirror is low. The grinding wheel is worn seriously, the aspheric surface is poor, and the subsurface damage of the mirror blank is serious, so the accuracy of the aspheric surface is improved. It is important to reduce aspheric subsurface damage and improve grinding efficiency. In this paper, the grinding process of large aperture SiC aspheric mirror is optimized to improve the surface shape and reduce the damage. In order to improve the efficiency, the residual height model considering the radial wear of grinding wheel is established in the direction of busbar, and the surface error model is established on the basis of the helical track of arc grinding wheel processing aspheric workpiece. The influence law of the surface shape error of each technological parameter is analyzed, and the experiment of grinding aspheric mirror with arc grinding wheel is carried out, which verifies the correctness of the surface shape error model and modifies the model by using the correction coefficient. In order to deduce the radial wear of grinding wheel, the grinding ratio is studied experimentally. The regression equation of grinding ratio is established. The surface error model provides a theoretical basis for the optimization of grinding process. The experiments of surface grinding of reactive sintering SiC ceramics are carried out. The surface / subsurface quality of SiC ceramics after grinding was studied, and the depth of subsurface crack, the depth of surface fracture layer and the removal mechanism of SiC ceramics were studied under different technological parameters. The surface quality under different parameters is compared and analyzed. The influence of process parameters on the depth of subsurface crack, the depth of surface fracture layer and the surface roughness are analyzed. The process parameters are optimized. The research of subsurface damage and the optimization of technological parameters lay a theoretical foundation for the selection of grinding parameters. The optimization strategy of grinding process for large aperture mirror is put forward. Including grinding mode analysis and selection, grinding wheel motion track analysis and selection, grinding wheel wear based on the establishment of surface error compensation model, based on the change of feed speed and other residual height optimization. Analysis and selection of grinding layer thickness, analysis and calculation of grinding efficiency; The grinding process of large diameter SiC mirror is optimized by the process optimization strategy. The surface shape error and grinding efficiency of the optimized and normal machining are compared and analyzed, and the surface shape accuracy of the aspheric surface is improved. The subsurface damage depth is reduced and the machining efficiency is improved. Finally, an optimization strategy suitable for the grinding of large aperture mirror is formed.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TQ174.6

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