改善机床运动的五轴刀轨光顺方法

建立了五轴数控加工刀轨光顺优化模型,改善了线性插补方式下拐角过渡运动中的机床加速度情况。考虑了5个轴加速能力的差异,以轴加速度比,即轴实际达到的最大加速度与其允许最大加速度的比值,来衡量轴的加速度情况,以5个轴加速度比的平方平均数在整体上衡量机床的加速度情况,降低该值可提高机床运动平稳性。采用最短距离线法在初始刀轨的各切触点处建立了刀轴偏航角和俯仰角的可行域,使光顺后的刀轨满足残高和无过切要求。实例表明:该方法可有效光顺五轴数控加工刀轨,改善机床加速度情况,提高机床运动平稳性。

5-axis tool path smoothing to improve machine tool motion

An optimization model of tool path smoothing in 5-axis CNC machining is built to improve the machine tool acceleration condition in the tool path corner transition motion in linear interpolation. Considering the difference of the five axis acceleration abilities, the ratio of one axis' maximal acceleration in corner transition motion and its allowed maximal acceleration is used to evaluate its acceleration condition, and the root-mean-square value of the five axis acceleration ratios is used to evaluate the machine tool acceleration condition, decreasing which can increase the stability of machine tool motion. The shortest lines method is used to build an admissible domain for tool axis tilt and yaw angles at each cutter contact point in the initial tool path in order to make the tool path respect the cusp height and no gouging constraints after smoothing. An example is given to demonstrate the feasibility of this method in improving the machine tool acceleration condition and increasing the stability of machine tool motion by smoothing the tool path.