自由曲面光学元件与球面和非球面光学元件相比能够提供更高的光学设计自由度, 应用于成像光学系统有利于简化系统结构和改善系统质量, 在新一代空间光学遥感领域具有广阔的应用前景。为了满足离轴反射式自由曲面空间光学遥感系统的快速、高精度研制需求, 本文瞄准微晶材质、复杂连续曲面类自由曲面反射镜超声铣磨加工表面粗糙度和亚表面质量的提升目标, 开展了主轴转速、切削深度、进给量等主要工艺参数的优化实验和研究, 完成了300 mm口径自由曲面反射镜的建模分析和超声铣磨加工, 最终铣磨加工表面的面形精度达8.89 μm PV, 亚表面损伤层深度低于18 μm, 实现了自由曲面光学反射镜的高精度、低损伤铣磨加工, 能够有效降低后续研抛加工的材料去除总量, 缩短整个加工周期。

Freeform optics are greatly in demand for use in next-generation space cameras for achieving higher optical design freedom as compared with the commonly used spherical and aspherical elements. Freeform optics have the advantages of excellent optical performance and simplified system structure. The development of optical remote sensing technology imposes higher requirements on these optics. Therefore, a series of optimization procedures of grinding process parameters for zerodour mirrors were conducted, and the grinding of a 300 mm aperture freeform mirror was completed using the optimized process parameters. The results show that the surface figure of the mirror increases to 8.89 μm PV, and the depth of the subsurface damage layer reduces to less than 18 μm. Realizing high precision and low damage grinding of freeform optics is of great significance for reducing the workload of subsequent lapping and polishing.