基于斜置锥台的五轴数控机床加工精度预测技术

摘要

This paper presents a new cone frustum based method for evaluation of the machining precision of five-axis numerical control ( NC) machine tools with the purpose of reducing the evaluation time and the evaluation cost. The method uses the theory of homogeneous transfer matrix ( HTM) to establish the kinematic error model of machining a cone frustum on a five-axis NC machining tool, and simulates the machining of the cone frustum using the computer aided manufacturing ( CAM) software Unigraphics NX4 ( UG NX4) to obtain the NC codes for machining the cone frustum. Then the roundness error of the cone frustum is calculated through the spatial relationship between cutting tool and workpiece according to the established model and the NC codes. Based on this, the machining precision of the five-axis NC machine tool is predicted. The simulation results demonstrate that the presented method is effective and can be used in practice.%为缩短基于斜置锥台评价五轴联动加工精度的时间和降低评价的费用,用多轴机床误差理论研究了基于锥台的五轴机床联动加工精度预测,提出了一种新的五轴机床加工精度评价方法.该方法利用齐次坐标变换理论建立斜置锥台的五轴加工运动误差模型,在计算机辅助制造(CAM)软件上进行斜置锥台的仿真加工得到斜置锥台刀侧铣削的数控(NC)代码,并利用运动误差模型和NC代码通过刀具与工件之间的空间位置关系计算出锥台侧面的圆度误差,据此对五轴联动数控机床的加工精度进行预测.对所提出的五轴加工精度预测方法进行了仿真分析,结果表明该方法简单实用,可以用于五轴联动加工精度的评价.