Abstract: For the low computational efficiency and the inadequate maximization of machining strip width,a multi-point contact cutter orientation calculation method based on genetic algorithm was proposed for the toroidal cutter of 5-Axis NC machining.After transforming the initial toroidal cutter model with the given yaw angle and tilt angle and transforming the cutter orientation optimization area,the directed shortest distance between the discrete cutter model and the surface of the cutter orientation optimization area was accurately calculated for avoiding local gouging.To accurately calculate the machining strip width,the cutter model was moved by the directed shortest distance and then intersected with the constant scallop-height offset surface of the surface in the cutter orientation optimization area.Regarding the cutting strip width as the optimization target and regarding the yaw angle and tilt angle as the coding variables,a genetic algorithm was used to find the optimal yaw angle and tilt angle corresponding to the maximum machining strip width.Examples showed that the proposed algorithm could effectively achieve the optimization of 5-axis machining cutter orientation of toroidal cutter with the larger machining strip width and the higher computational efficiency.

Key words: five-axis NC machining, toroidal cutter, multi-point contact, genetic algorithms, shortest directed distance

摘要： 针对目前五轴数控加工环形刀具多点切触刀位优化算法计算效率不高、切削带宽尚有提升空间的问题,提出一种基于遗传算法的多点切触刀位计算方法。为避免局部干涉,在将初始环形刀具模型和刀位优化区域变换到指定位置的基础上,精确计算给定倾斜角、侧偏角的离散刀具模型与刀位优化区域曲面之间的最短有向距离。为精确计算切削带宽,将刀具模型移动最短有向距离后,与刀位优化区域曲面的等残留高度偏置曲面进行求交,获得近似于实际的切削带宽。以切削带宽为优化目标,以倾斜角、侧偏角为编码变量,采用遗传算法寻优获得最大切削带宽所对应的刀位倾斜角、侧偏角。算法运算实例表明,所提算法能够有效实现环形刀具的五轴加工刀位优化,最优刀位对应的切削带宽更大,计算效率也更高。

关键词: 五轴数控加工, 环形刀具, 多点切触, 遗传算法, 最短有向距离