Optimization method of tool axis vector based on kinematical characteristics of rotary feed axis for curved surface machining
Optimization method of tool axis vector based on kinematical characteristics of rotary feed axis for curved surface machining
复制标题
基于回转进给轴运动特性的曲面加工刀轴矢量优化方法
DOI：
10.1007/s00170-018-2738-7
复制
发表时间：
2019
影响因子：
3.4
通讯作者：
Jia Zhen-yuan
中科院分区：
文献类型：
--
作者：
Ma Jian-wei;Hu Guo-qing;Qin Feng-ze;Su Wei-wei;Jia Zhen-yuan
复杂曲面零件在工业应用中应用广泛，曲面零件通常采用球头刀五轴数控加工方法。与三轴数控加工相比，由于增加了旋转进给轴，曲面加工的刀具姿态控制较为复杂。随着曲面零件的日益复杂，在曲面加工中很容易出现旋转进给轴的大幅度非共格运动，甚至可能超出机床内旋转进给轴的运动性能，从而影响曲面零件的加工质量，这是一个众所周知的问题。为了克服这一问题，提出了一种基于曲面加工回转进给轴运动特性的刀具轴矢量优化方法。首先，根据旋转进给轴转角与刀路累积弧长之间的关系，选择刀路对刀轴矢量的优化区间；然后，利用基于四元数法的刀轴矢量均衡方法，结合旋转进给轴的运动特性对刀轴矢量进行优化。最后，在对刀具轴向矢量进行局部优化后，利用最小二乘拟合原理对优化后的旋转进给轴角值和累计弧长变化曲线进行调整。通过对被试零件的仿真和实验验证了所提方法的有效性，所取得的成果对提高复杂曲面零件的加工质量具有重要意义。
Complex surface parts are widely used in the industrial applications, and 5-axis NC machining with ball-end cutter is the commonly adopted method for curved surface parts. Due to the additional rotary feed axis comparing with 3-axis NC machining, the tool orientation control is complex for curved surface machining. With the more complexity of curved surface parts, it is a known problem that the large incoherent movement of the rotary feed axis will easily appear in curved surface machining, which may even be beyond the kinematical performances of the rotary feed axis in machine tool, so as to affect the machining quality of curved surface parts. In order to overcome this issue, an optimization method of tool axis vector based on the kinematical characteristics of the rotary feed axis for curved surface machining is proposed. Firstly, the optimizing interval of the toolpath for tool axis vector is selected based on the relationship between the rotation angle of rotary feed axis and the accumulation arc length of toolpath. Then, the equalization method of tool axis vector based on the quaternion method is used to optimize the tool axis vector with the kinematical characteristics of rotary feed axis. Finally, the angular change curve of rotary feed axis with the optimized angular value and cumulative arc length is adjusted by the principle of least-squares fitting after the local optimization of tool axis vector. Simulation and experiment on test parts are carried out to verify the validity of the proposed method, and the achievements are significant to improve the processing quality of complex curved surface parts.