大口径离轴非球面离心力误差修正的车削方法  

Turning method for correcting centrifugal force error of largediameter off-axis aspheric surface

作　　者：宋鹏 白杨[2] 杨超 李闯[1] 薛常喜[1] 丁佳雯 郭杰 Song Peng;Bai Yang;Yang Chao;Li Chuang;Xue Changxi;Ding Jiawen;Guo Jie(School of Optoelectronic Engineering,Changchun University of Science and Technology,Changchun 130022,China;Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,China)

机构地区：[1]长春理工大学光电工程学院,吉林长春130022 [2]中国科学院长春光学精密机械与物理研究所,吉林长春130033

出　　处：《红外与激光工程》2023年第7期267-275,共9页Infrared and Laser Engineering

基　　金：国家自然科学基金项目(12203048);吉林省自然科学基金项目(20230101217JC)。

摘　　要：大口径离轴非球面反射镜进行高精度车削过程中,由离心力引起的微米级面形误差变得尤为重要。为了减小离轴非球面反射镜在车削过程中受离心力变形而引起的面形误差,对离轴非球面铝合金反射镜开展了单点金刚石车削工艺研究。通过分析离心力产生机理,构建了抑制离心力坐标变换加工模型;利用有限元仿真的方法优化了坐标变换的平移位移和旋转角度,最后基于优化结果对口径320 mm的RSA6061铝合金离轴非球面反射镜进行车削实验,获得了面形精度为RMS 0.198λ(λ=632.8 nm)的离轴非球面铝合金反射镜,验证了该优化加工方法的有效性。上述优化方式能够显著提高单点金刚石车削加工大口径离轴非球面反射镜的加工精度。Objective As the core optical element of the off-axis optical system,the off-axis aspheric mirror has the function of reducing the volume of the optical system,increasing the field of view and improving the imaging quality.Aluminum alloy material is one of the commonly used materials for off-axis aspheric mirrors because of its high processing efficiency,low cost and the ability to realize the athermalized design of the optical systems.Due to the special application field of the off-axis optical system,the accuracy requirements of the off-axis aspheric surface are very strict.In the process of high-precision turning of large-diameter off-axis aspheric aluminum alloy mirrors,the micron-level surface shape error caused by centrifugal force becomes non-negligible.In order to reduce the surface shape error caused by centrifugal force deformation of off-axis aspheric aluminum alloy mirror during turning,it is necessary to study the single-point diamond turning process of off-axis aspheric aluminum alloy mirror.Methods Based on the basic principle of centrifugal force generation,a machining method to suppress centrifugal force error is proposed(Fig.4).Through the finite element simulation method,the translation displacement and rotation angle of the centrifugal force coordinate transformation machining model are optimized.Taking an off-axis aspheric aluminum alloy mirror with an aperture of 320 mm as an example,the optimal coordinate transformation parameters are reflected in the optimization results(Fig.6),and the off-axis aspheric mirror is used for ultra-precision turning.Results and Discussions Using the processing method of suppressing centrifugal force error,the off-axis aspheric surface of aluminum alloy with a diameter of 320 mm is processed by Nanoform 700 ultra diamond lathe,and the processing results are detected by Zygo interferometer.A high-precision off-axis aspheric aluminum alloy mirror with PV of 3.121λand RMS of 0.198λ(Fig.8)is obtained.The machining method of surface suppression centrifugal force e

关 键 词：光学制造 离轴非球面 离心力误差 金刚石车削 

分 类 号：TH161.2[机械工程—机械制造及自动化]