Structure optimization and performance analysis of an ion beam figuring machine for sub-nanometer optical surface
Ultra-precise surfaces are vitally important for high performance optical systems.Ion beam figuring (IBF) is a highly deterministic method for the final precision optical figuring.However,there are some key problems, such as small ion beam positioning error, dwell times realization accuracy, structural optimization of the quick-response platform, which restrict the obtaining of sub-nanometer precision and must be seriously considered.In this paper, we discuss the design philosophy of an IBF machine.Integrated dynamic optimization of the sliding worktable is performed to improve the dynamic performance of the quick-response platform.The positioning accuracy and its repeatability of Y-axis for full stroke have been improved to 5.9μm and 1.6μm,respectively.As regards the dynamic performance, the accelerating process of Y-axis is rapid and without obvious vibrations, and the acceleration can reach 3.2m/s2.Manufacturing tests on a fused silica spherical concave surface (φ135.7 mm, radius of curvature 340.5mm) are accomplished, and the final surface error is 0.375nm RMS, 3.06nm PVr after five iterations, indicates that the performance of the new designed IBF machine well meets requirements for sub-nanometer figuring.
Ion beam figuring (IBF) Sub-nanometer precision Structure optimization Positioning accuracy Dynamic performance
Mingjin Xu Yifan Dai Lin Zhou
National University of Defense Technology, Changsha, China
国际会议
上海
英文
5-9
2017-11-19（万方平台首次上网日期，不代表论文的发表时间）