平转动大磨头加工大口径非圆形球面的粗磨试验

摘要

提出了用于大口径非圆形球面反射镜研磨和抛光的平转动大磨头加工技术,该技术基于平转动小磨头计算机控制光学表面成形技术,通过增大磨头口径的方式来提高其材料去除效率.针对大口径磨头比较突出的边缘效应,通过低阶拟合以及高阶补偿相结合的方法,在虚拟加工算法中引入边缘效应的影响,保证材料去除效率提高的同时具有一定的面形收敛率,从而有效地缩短加工周期.最后对一块1 100 mm×800 mm的体育场形SiC坯料进行了加工试验,共进行22轮加工,总加工时间约51 h,面形从122μm(PV)收敛至5.9 μm(PV).与传统小磨头加工技术相比,效率提高了1倍以上,实现了大口径非圆形球面在粗磨阶段的高效去除.%A large tools with orbital tool motion was adopted to upgrade the processing efficiency of the small tools with orbital tool motion based on Computer Controlled Optical Surfacing(CCOS)technology by enlarging the lap size. The edge effect that is common for large laps was simulated and compensated by combination of the first order approximation and the high order compensation to improve the convergence rate and to maintain better remoral efficiency. Therefore, the processing periods were shortened effectively. A round square of 1 100 mm X 800 mm SiC mirror was grinded with this method. After 22 runs of 55 hours in all processing, the overall surface error is 122μm PV before and 5. 9/μm PV after the process. Comparing with that of previous small lap technology, the efficiency is im-proved by a factor of at least 2.