Li Zelong, Dai Yifan, Guan Chaoliang, Yong Jiahao, Sun Zizhou, Du Chunyang
College of Intelligence Science and Technology, National University of Defense Technology, 109 Deya Road, Changsha 410073, China.
Hunan Key Laboratory of Ultra-Precision Machining Technology, Changsha 410073, China.
Micromachines (Basel). 2021 May 24;12(6):607. doi: 10.3390/mi12060607.
Weak-stiffness mirrors are widely used in various fields such as aerospace and optoelectronic information. However, it is difficult to achieve micron-level precision machining because weak-stiffness mirrors are hard to clamp and are prone to deformation. The machining errors of these mirrors are randomly distributed and non-rotationally symmetric, which is difficult to overcome by common machining methods. Based on the fast tool servo system, this paper proposes a high-precision machining method for weak-stiffness mirrors. Firstly, the clamping error and cutting error compensation strategy is obtained by analyzing the changing process of the mirror surface morphology. Then, by combining real-time monitoring and theoretical simulation, the elastic deformation of the weak-stiffness mirror is accurately extracted to achieve the compensation of the clamping error, and the compensation of the cutting error is achieved by iterative machining. Finally, a weak-stiffness mirror with a thickness of 2.5 mm was machined twice, and the experimental process produced a clamping error with a peak to valley (PV) value of 5.2 µm and a cutting error with a PV value of 1.6 µm. The final machined surface after compensation had a PV value of 0.7 µm. The experimental results showed that the compensation strategy proposed in this paper overcomes the clamping error of the weak-stiffness mirror and significantly reduces cutting errors during the machining process, achieving the high precision machining of a weak-stiffness mirror.
弱刚度反射镜在航空航天、光电信息等诸多领域有着广泛应用。然而，由于弱刚度反射镜难以夹紧且容易变形，实现微米级精度加工较为困难。这些反射镜的加工误差呈随机分布且非旋转对称，采用常规加工方法难以克服。基于快速刀具伺服系统，本文提出了一种弱刚度反射镜的高精度加工方法。首先，通过分析镜面形貌的变化过程得出夹紧误差和切削误差补偿策略。然后，结合实时监测与理论模拟，精确提取弱刚度反射镜的弹性变形以实现夹紧误差补偿，并通过迭代加工实现切削误差补偿。最后，对厚度为2.5毫米的弱刚度反射镜进行了两次加工，实验过程中产生的夹紧误差峰谷值（PV）为5.2微米，切削误差PV值为1.6微米。补偿后的最终加工表面PV值为0.7微米。实验结果表明，本文提出的补偿策略克服了弱刚度反射镜的夹紧误差，在加工过程中显著降低了切削误差，实现了弱刚度反射镜的高精度加工。
