离轴非球面SiC反射镜的精密铣磨加工技术  

Precision Grinding Technology for the Off-axis Aspherical Silicon Carbide Mirror Blank

作　　者：张志宇[1] 李锐钢[1] 郑立功[1] 张学军[1] 

机构地区：[1]中国科学院长春光学精密机械与物理研究所中国科学院光学系统先进制造技术重点实验室,长春130033

出　　处：《机械工程学报》2013年第17期39-45,共7页Journal of Mechanical Engineering

基　　金：国家重点基础研究发展计划(973计划,2011CB013200);国家自然科学基金(61036015)资助项目

摘　　要：离轴非球面反射镜是高分辨率、大视场空间相机的核心元件,其镜面的形状精度和表面质量要求极高,加工难度很大,一直是光学系统先进制造技术的瓶颈。针对国家对空间大型SiC光学元件制造技术的重大需求,开展以大口径、高陡度、大离轴量和大偏离量为特点的离轴非球面反射镜的精密铣磨加工技术研究。开发非球面反射镜计算机辅助数控编程技术,提出五轴联动斜轴定角度加工方式,建立旋转中心在镜面外的螺旋加工轨迹,避免镜面几何中心处的加工残留。并基于五轴加工中心(型号DMG Ultrasonic 100-5)搭建超声振动辅助铣磨加工平台,以900 mm×660 mm口径离轴非球面SiC反射镜镜坯为加工样件进行工艺试验,加工面形精度峰谷值(Peak to valley,PV)达到18.8μm,方均根值(Root mean square,RMS)达到3.5μm。研究为按照非球面方程高精度铣磨超大尺度精度比离轴非球面反射镜提供了有效的解决方案。Off-axis aspheric mirrors are the key components in a high-resolution,large field-of-view space camera,and are very hard to machine due to extremely strict requirements on shape accuracy and surface quality.Therefore it is a bottleneck of the advanced optical manufacturing technology.Computer-aided NC programming techniques for mirror blanks with large-diameter,high-steepness,large-deviation,and large off-axis-amount are developed.An oblique five-axis processing method with a decenter spiral tool path is proposed to avoid the residual shape error in the geometric center of mirror blank.Based on a five-axis ultrasonic vibration-assisted machining center,a 900 mm×660 mm diameter off-axis aspheric SiC mirror blank is successfully machined,obtaining a surface accuracy of 18.8 μm peak to valley（PV）,and 3.5 μm root mean square（RMS）.Effective and precision machining technologies in accordance with the equation of the off-axis aspherical mirrors with huge scale-precision ratio are provided.

关 键 词：离轴非球面 SiC反射镜 精密磨削 CAD CAM 加工轨迹优化 超声振动辅助加工 

分 类 号：TG58[金属学及工艺—金属切削加工及机床]