基于改进Z-MAP算法的球头铣刀加工表面形貌仿真与试验研究

Simulation and Experimental Study of Ball-end Milling Surface Topography Based on an Improved Z-MAP Algorithm

基于时间步长法提出一种仿真球头铣刀加工表面形貌的改进Z-MAP算法。该算法在建立刀齿运动轨迹方程的基础上,使用随动矩形包围圈和角度累加法快速地获取工件上的瞬时被扫掠点,并引入牛顿迭代法求取这些点的高度坐标。无须对刀齿离散,不但突破传统Z-MAP算法中单位时间步长内刀齿离散段至多只能扫掠过一个工件离散点的限制,还可以获得更高的精度和效率。通过仿真分析进给行距、每齿进给量、刀具姿态和刀具进给起始相位差等参数对表面形貌及其表面粗糙度的影响规律,并选用航空铝合金7050进行了铣削加工试验验证,试验结果表明改进Z-MAP算法仿真结果与实际加工的一致性更高,对实际生产中加工参数的合理选择具有指导意义。

Based on the time step method, an improved Z-MAP algorithm is proposed to simulate the ball-end milling surface topography. In the basis of establishing of the cutter tooth movement equation, this algorithm use servo rectangular encirclement and the angle sum method to quickly obtain the instantaneous swept points on the workpiece, and introduce Newton iterative method to calculate the height of these points. It does not needed to discretize the cutting tooth, and relative to traditional Z-MAP algorithm, it not only breaks the limit which is that cutting tooth discrete segments can at most sweep across only one discrete point on the workpiece during an unit time step, but also could get higher precision and efficiency. On these bases, the influence rules of some parameters, such as path interval, feed per tooth, tool posture and the initial phase angle difference of cutter＇s feed, on the surface topography and roughness are analyzed. Aviation aluminum alloy 7050 is selected as milling material to make experiments, and the experimental results show that surface topographies simulated by the improved Z-MAP algorithm have higher consistency with practical processing ones, and have directive significance in rational selection of machining parameters in practical production.