大型光学非球面零件超精密切削新方法

A new method of ultra-precision diamond turning large optical aspheric surface

超精密切削加工机床的刀具进给一般采用直线导轨实现,分析并提出以刀具的旋转运动代替直线进给运动方式,实施轴向与径向进给,并通过控制车刀的微进给量实现非球面的超精密加工.通过二次曲面曲率分析,给出避免产生过切的非球面最接近球面的求解方法;构建了车刀微进给系统进给的几何模型.计算机模拟表明:该加工方法可以提高大型非球面加工精度,并且制造同等精度设备难度小、成本低,结构紧凑、刚性变形小,可提高生产效率.

Linear motion guides are employed in the feed system of most of diamond turning machine. For rotary axes can be made less expensive, easier and more compact than a linear guide at the same precision level, a rotary arm that carries a diamond tool combined with a micro-feed system at the tool tip through a circular path is used to replace the straight lines. The reference sphere of the aspheric surface can be determined by the angle between the rotating axes of the cutter arm and the workpiece, and by controlling the feed of the micro-feed system, ultra-precision large aspheric surfaces can be turned. The calculating method of the reference sphere to avoid over-cutting is introduced based on curvature analysis. Geometric model of the feed for microfeed system is presented. The mac with high machining accuracy, low efficiency can be improved and the approach is verified by computer simulation to be simple and reliable cost, cramped construction and small rigid deformation, so the production equipment input can be reduced.