任意扭曲直纹面叶轮数控侧铣刀位计算与误差分析

Calculation of Cutter-location and Error Analysis in Numerical Control Flank Milling of Twisted Ruled Surface Impeller

提出了一种计算数控侧铣任意扭曲直纹面叶轮刀位数据的新方法:沿直纹面母线两端点的法矢量偏置一定距离得到2个点,以这2个偏置点所在的直线作为刀轴方向,并使母线两端点到刀轴的距离为刀具半径,推导出了在利用圆柱铣刀侧铣直纹面时刀具与曲面切触线的方程以及加工误差的计算方法,并以计算实例验证了该算法的正确性.这种加工方法使直纹面2条基线的加工误差为0,适合于沿直纹面叶片高度方向分层加工,分层加工后相邻走刀的残留高度理论值为0.

A method of calculating cutter-location in numerical control flank milling of twisted ruled surface impeller is presented. The two end points of generatrix of ruled surface are offsetted along their normal vector by a given distance, and the line linking the two offsetted points is taken as the cutter axis. The distance from two offsetted points to cutter axis is determined as the cutter radius. The equation of contact curve between cylinder cutter and ruled surface in machining is induced, and the machining error estimation is provided. This method can keep the machining error on two end points of generatrix to be zero. The scallops between adjacent tool paths are zero in theory when it is applied for flank milling of ruled surface in layers along height direction of blade.