光学 精密工程, 2014, 22 (8): 2109, 网络出版: 2014-09-15
热压硫化锌的超精密磨削加工
Ultra-precision grinding of hot-pressed zinc sulfide
热压硫化锌透镜 压痕实验 临界切削深度 单颗粒刻划 平面磨削 亚表面损伤 表面质量 hot-pressed zinc sulfide lens micro-indentation experiment critical cutting thickness single-point diamond scratching surface grinding subsurface damage surface quality
摘要
针对用传统车削或研磨抛光方法加工大尺寸非球面热压硫化锌透镜存在的不足,采用金刚石砂轮磨削加工方法对热压硫化锌材料进行了加工实验。通过压痕、单颗粒金刚石刻划和磨削正交实验,研究了该方法在磨削加工过程中的塑性域去除机理及其亚表面损伤情况,并优化了超精密磨削加工工艺参数。压痕实验发现热压硫化锌材料在载荷作用下易于出现径向裂纹和微裂纹,其断裂韧性为2.643842 MPa/m1/2,临界切削深度为1.808 μm。单颗粒金刚石刻划实验结果表明,热压硫化锌材料在较小的切削深度下可以实现塑性域去除,但在机械去除过程中易出现多种形式的亚表层损伤。磨削实验结果表明,磨削深度是影响表面光洁度的主要因素,随着磨削深度的增大表面光洁度降低,最佳表面粗糙度为7.6 nm。工作台进给速度是影响面形精度的主要因素,且平面磨削的面形精度PV值为0.185~0.395 μm。研究结果表明,磨削加工热压硫化锌材料可以获得纳米级表面粗糙度。
Abstract
To overcome the shortcomings of traditional lapping and polishing methods in machining large size aspherical hot-pressed zinc sulfide lenses, a machining experiment on hot-pressed zinc sulfide materials was performed by diamond wheel grinding method.. The single-point diamond scratching and orthogonal grinding experiments were carried out to research the ductile regime removal mechanism and subsurface damage during machining hot-pressed zinc sulfide and to obtain optimal machining parameters. The results of micro-indentation experiment show that hot-pressed zinc sulfide materials under a load are easy to produce radial cracks and micro cracks, the toughness value is 2.643842 MPa/m1/2 and the critical cutting depth is 1.808 μm. Based on the results of single-point diamond scratching, it verifies that hot-pressed zinc sulfide is removed in ductile regime at a smaller cutting depth although much kinds of subsurface damage will appear during machining process. The results of orthogonal grinding experiments demonstrate that the depth of grinding is a main influencing factor on surface roughness values, which decreases with decreasing depth of grinding, and the best value is 7.6 nm. The feed rate of the working table influences the surface figure precision PV values mostly, it offers the surface accuracy(PV) between 0.185 μm and 0.395 μm. These results show that the roughness of hot-pressed zinc sulfide surface by grinding has been up to nano level.
陈冰, 郭兵, 赵清亮, 饶志敏, 姚光. 热压硫化锌的超精密磨削加工[J]. 光学 精密工程, 2014, 22(8): 2109. CHEN Bing, GUO Bing, ZHAO Qing-liang, RAO Zhi-min, YAO Guang. Ultra-precision grinding of hot-pressed zinc sulfide[J]. Optics and Precision Engineering, 2014, 22(8): 2109.