复杂曲面铝反射镜磁流变抛光工艺优化

采用超精密车削加工的复杂曲面铝反射镜只能满足红外光学系统的应用需求，若要满足更高需求的应用场合，需要进一步提升反射镜面形精度。磁流变抛光能够进行确定性修形，在复杂曲面加工中具有独特优势，但是复杂曲面连续变化的面形特征，在磁流变抛光时会导致去除函数不稳定，影响误差收敛效率和加工精度。从高精度复杂曲面铝反射镜的应用需求出发，提出了复杂曲面局部区域磁流变抛光去除函数的动态建模方法，给出了驻留时间求解算法，以平均曲率变化最小为原则，设计了抛光路径优化算法，针对该算法计算速度慢的问题，提出了优化策略，并通过试验进行了验证，最终加工的复杂曲面铝反射镜的面形误差为0.216λ PV、0.033λ RMS （λ=632.8 nm）。

Optimization of magnetorheological finishing process for aluminum mirror with complex surface

The complex curved surface aluminum mirror processed by ultra-precision turning can only meet the application requirements of the infrared optical system. To meet higher application requirements, it is necessary to further improve the shape accuracy of the reflector. Magnetorheological finishing has unique advantages in complex surface machining as it can be used for deterministic shape modification. However, the continuous change of complex surface shape will lead to instability of removal function and affect the error convergence efficiency and machining accuracy. In this paper, according to the requirements for application of the high-precision complex curved surface aluminum mirror, a dynamic modeling method of MRF removal function in local area of complex surface is proposed, and solution to the dwell time algorithm is given. Based on the principle of minimum average curvature change, a polishing path optimization algorithm is developed. To solve the problem of slow calculation speed of the algorithm, the optimization strategy is put forward. Experiments verifies that the shape error of the finally obtained complex curved surface aluminum mirror is 0.216λ PV and 0.033λ RMS (λ=632.8 nm).