等重叠率螺旋线的非球面抛光轨迹规划

Uniform-Overlap-Rate Spiral Path for Aspheric Polishing

为改善抛光轨迹以获得更好的加工精度,分析了轨迹在非球面上所产生的去除区域的覆盖情况,并提出了一种等重叠率螺旋线抛光轨迹规划方法。基于赫兹接触理论的去除区域的覆盖情况分析表明,常用的阿基米德螺旋线由于弹性接触变化和投影行距变化导致轨迹间去除区域接触变化,从而不能保证加工精度均匀一致,为此引入了重叠率的概念以量化分析该变化情况。提出的轨迹规划方法分析了重叠率的变化特点,并依据螺旋线的性质建立了螺旋线行距与非球面面形的变化关系,保证了轨迹间去除区域的稳定接触。仿真结果表明,在非球面抛光过程中应用等重叠率螺旋线轨迹,重叠率变化范围从阿基米德螺旋线轨迹的56.1%~26.2%缩小到现在方法的56.1%~55.3%,为非球面抛光的均匀性和一致性奠定了基础。

To improve the polishing path and obtain better machining accuracy,the removal area generated by path on aspheric surface is analyzed,and a novel spiral tool path planning with uniform-overlap-rate is proposed.The removal area analysis following Hertz contact theory shows that the generally used Archimedes spiral fails to ensure the uniform and consistent machining accuracy due to varying contact of the removal area brought from changed elastic contact and projection path interval. Thus the concept of overlap rate is introduced to quantitatively describe the varying contact.The characteristics of varying overlap rate are revealed in the proposed path planning,and the changing relation between spiral and aspheric surface is established to guarantee the stable contact of the removal area between adjacent tool paths.The simulation shows that the range of overlap rate decreases from 56.1%-26.2% for Archimedes spiral path to 56.1%-55.3% for the proposed uniform-overlap-rate spiral path in aspheric surface polishing.