自由曲面五轴变步长数控加工刀轨生成方法

Method of five-axis variable step NC machining tool path generation for free-form surface

为了在满足逼近误差要求的同时最大程度减少冗余刀轨,对自由曲面提出了一种五轴变步长数控加工刀轨生成方法。首先对刀触点轨迹基于线性误差计算出初始刀触点点集,再以局部干涉调整前倾角的方式计算出无干涉刀位点和刀轴矢量;以最大非线性误差刀位处到刀触点轨迹的最小值作为相邻刀位点之间的逼近误差,并基于数据点自适应离散法计算逼近误差;在满足逼近误差要求的前提下,通过刀触点参数迭代增减步长的方式计算出最大步长;最后对曲面生成刀轨,验证了算法的可行性和有效性。

In order to reduce redundant tool path as much as possible while meeting the requirement of step error,a method of tool path generation in five-axis variable step Numerical Control(NC)machining free-form surface was presented.Firstly,initial Cutter Contact(CC)points on CC path were calculated based on linear error.Interference-free Cutter Location(CL)points and tool vectors were calculated by local interference adjusting inclination angle.For the adjacent CL points,the minimum value from the cutter location with maximum non-linear error to the CC path was proposed as the step error,and the step error calculation method based on the method of self-adaptive data point discretization was proposed.On the premise of meeting the requirements of step error,the method of increasing or decreasing the step size by parameter iteration of CC point was proposed to calculate the maximal step.Finally,the presented method was implemented to generate tool path for free-form surface,which verified the feasibility and effectiveness of the method.