超精密平面飞切机床关键技术研究

研制了一种用于KDP晶体加工的平面飞切机床,该机床直线轴基于直线电动机驱动、液体静压导轨支承;刀具旋转轴采用高刚度气浮主轴+高刚度主轴旋转机构。基于高精度分辨率位置反馈+线性驱动器+PID控制算法,直线轴获得了1 mm/min速度下,0.018 mm/min的低速波动以及±0.01μm的位置精度;刀具微进给装置采用差动螺纹进给来实现,最终获得了进给分辨率1μm、锁紧后位置移动量小于1μm高精度进给。在优化工艺参数后,金刚石飞切机床加工100 mm×100 mm×10mm的KDP晶体后获得表面粗糙度Rq优于2 nm高精度指标;加工400 mm×400 mm×30 mm的铝镜后获得面形PV值优于3μm的高精度指标。

Research on key technologies of ultra-precision plane flying cutting machine tool

In this paper,a plane flying-cutting machine tool for KDP crystal is developed. The linear axis of the machine is driven by linear motor and supported by hydrostatic guideway. High stiffness air-bearing spindle and high stiffness spindle rotating mechanism is adopted for tool spindle. Based on the high resolution position feedback and linear driver and PID control algorithm,the low-speed fluctuation of 0.018 mm/min and the position accuracy of 0.01 μm at 1 mm/min speed are obtained. The tool micro-feeding device is realized by differential thread feeding,and the high precision feeding with a feed resolution of 1 micron and a position displacement of less than 1 micron after locking is finally obtained. After optimizing the process parameters,the experiment of diamond flying-cutting machine tool on 100 mm×100 mm ×10 mm KDP crystal shows that the surface roughness Rq is better than 2 nm. High precision index of surface PV value better than 3 micron is obtained after processing 400 mm × 400 mm × 30 mm aluminum mirror.