端点误差控制刀位算法的改进

Improvement of End-point Error Controlling Tool Path Generation Method

对端点误差控制数控加工刀位算法进行了改进:采用2个端点间偏置距离代替它们的参数差值用于衡量加工带宽和进行加工误差控制,提出了一种新的采用循环迭代计算刀具旋转角度的方法,并给出了格点法对偏置方向角进行优化的过程;使得算法不受具体的曲面参数化方式影响,简化了刀具定位时计算量,刀位得到了充分的优化。利用UG二次开发技术进行的实例计算表明:设置走刀方向沿着曲面的最小主曲率方向比沿着曲面的最大主曲率方向加工带宽更宽,前者应该是该算法的最优走刀方向,而且沿着最优方向走刀的优化刀位和多点切触加工算法得到的加工刀位一致,该算法也比多点切触加工算法有更大的适应性。

Much improvement is made on the end point error controlling tool path generation method in NC machining. Instead of the difference of surface parameters between the two end points, the offset distance is taken as a variable to represent the cutter path interval and used in machining error controlling. A novel iterative method is proposed in the cutter rotation angle calculation, and the procedure with grid point method for the optimal offset direction angle is introduced. During the improvement, the parameterization of the surface has no influence on the algorithm, the computation cost for tool positioning is also reduced, and the tool path is optimized thoroughly. The computation example carried out with UG further development technology indicates that the tool path interval generated when taking the direction of minimal principle curvature of surface as the feed direction is wider than that when taking the direction of maximal principle curvature of surface as feed direction. And the former should be the optimal feed direction. It also shows that the tool path generated using the algorithm is the same as that generated using multi-point machining method when taking optimal direction as feed direction, but the novel algorithm is more robust.