复杂光学表面的快刀伺服加工特性与路径规划

Machining Characteristics and Route Planning of Complex Optical Surface by Using Fast Tool Servo

复杂面形和微结构阵列等类型的光学元件应用范围越来越广,传统的机械加工方法难以满足面形精度和加工效率要求,超精密快刀伺服(Fast tool servo,FTS)是实现这类零件优质高效加工的有效手段。但是在复杂光学表面的快刀伺服加工中,面形的高低起伏将会使刀具和工件的相对位置实时变化,导致加工状态恶化、面形精度下降,甚至会产生刀具干涉和过切现象。针对这种情况,通过研究复杂面形快刀伺服加工中切削角的变化规律及其对刀具前角、后角的影响,给出刀具干涉的判断算法以及工艺参数的选取依据;为实现加工路径的合理规划,进行典型复杂光学表面的刀具补偿分析与算法设计;在此基础上,以正弦放射线作为对象,进行快刀伺服加工试验,测试结果表明加工面形精度达到PV 0.17μm,没有发生过切和刀具干涉现象。

Optical components with complex surfaces or microstructure array are more and more widely applied,but it is very difficult to satisfy the requirements of surface accuracy and machining efficiency by using traditional mechanical fabricating methods.Ultraprecision fast tool servo（FTS） system can manufacture these complex surfaces efficiently and accurately.The relative position between the tool and workpiece surface will vary continuously in the FTS machining process,owing to the height change of workpiece profile,and this will worsen the cutting conditions,debase the machining accuracy,and even produce the phenomenon of tool interference and over-cut.In view of the situation,the varying rules of cutting angle are studied in the FTS machining process of complex workpieces,as well as the influences on rake angle and back angle of the tool.The algorithms for identifying tool interference and the selection basis of machining parameters are given.In order to realize rational route planning,the analysis and algorithm design of tool compensation are accomplished in the machining process of typical complex optical surface.On the basis of the above work,a kind of representative complex workpiece,radial sinusoidal workpiece,is manufactured by using the FTS system.The measuring results indicate that accuracy of machined surface can reach PV 0.17 μm,and the over-cut and tool interference do not occur.