基于包络面构建的等残留高度刀具路径规划

Constant Scallop-height Tool Path Planning by Constructing Envelope Surface

提出一种基于包络面构建技术的等残留高度刀具路径规划方法。在计算过程中,首先分别以残留高度值和刀具半径值为等距距离将被加工曲面进行等距,得到残留曲面和刀具中心曲面。然后以前一行刀具路径为引导线,构建截面半径等于刀具半径的包络面,通过包络面与残留曲面之间的求交计算,得到残留曲线;以残留曲线为引导线,再次构建包络面,包络面与刀具中心曲面之间的交线即为当前刀具路径行。依次递推,求出所有刀具路径行。最后针对可能出现的欠切问题,给出边界处理方法。通过实例验证了算法的可行性,并与现有算法进行比较,表明应用该方法生成三坐标自由曲面加工的刀具路径,可在保证加工精度的前提下,大大提高加工效率。

A constant scallop-height tool path planning method was presented based on envelope surface construction. Firstly, in the process of calculation, the machined surface was offset by the distance of tool radius and scallop-height respectively, then the scallop surface and the tool center surface were obtained. Then the envelope surface, whose section radius was equal to the tool＇s, was constructed along the last tool path. The scallop curve was obtained by the envelope surface intersection calculation with the scallop surface. The envelope surface was again constructed along the scallop curve. The adjacent tool path was the intersection line of the envelope surface and the tool center surface. All tool paths could be determined by recurring in turn. A method of boundary verification was described to avoid undercut. Finally the validity of present method was demonstrated by an example. The calculation results of the present method were compared with those of the existed algorithms. The results indicate that the machining precision and efficiency can be enhanced greatly with three-axis free form surface machining.