为提高自由曲面环形刀五轴精加工的效率,在广域空间中分析刀具的干涉误差,对曲面宽行加工的刀具方位优化方法进行研究。首先根据环形刀刀具特性,定义曲面可能干涉的区域为广域空间,然后将广域空间离散点集变换至刀具坐标系中,计算刀具刀刃曲面的干涉误差,从而构建刀具的实际切削轮廓,并在此基础上精确计算有效的加工带宽。最后,通过建立刀具方位与加工带宽的函数关系,以加工带宽最大化为目标,实现环形刀五轴宽行加工刀具方位的自动优化。算例及试验表明,在相同的残留高度要求下,广域空间方法较之现有的二阶泰勒逼近方法,切触点轨迹长度减少了15.74%,说明基于广域空间的刀轴优化方法是实现自由曲面宽行加工的有效途径。
To improve the cutting efficiency for five-axis finish machining of free-form surface,a new approach to tool orientation optimization for strip-width-maximization machining based on global space is presented.Firstly,according to the character of the toroidal-end cutter,the global space is defined by a series of discrete points which may be gouged with the surface.Then the actual cutting profile is constructed with the cutting points those distances from the cutter are less than the calculating accuracy.Moreover,the effective machined strip width is accurately calculated.Finally,the tool orientation is optimized by maximizing the machined strip width based on the mapping between the tool orientation and the machined strip width.Example and experiment show that the length of the tool path of the new algorithm is reduced by 15.74% comparing with the second order approximation method at the same scallop height.It suggests that the cutting error can be controlled effectively and the proposed method is an effective way of improving machining efficiency for five-axis machining of free-form surface.