Abstract: Focusing on the global interference in five-axis end milling of complex tunnel parts, a new method which avoids interference by critical constraint and the calculation of precise critical position is presented. Based on the features of global interference and the intersection line between the plane perpendicular to the direction of cutter moving and the surface to be machined (SM) in the cutting contact (CC) point, the initial critical position is calculated. In the part coordinate system, the function of the auto-program tool (APT) cutter flank is constructed, and the point set close to the cutter-flank is selected based on the critical position. In the tool coordinate system, the minimum distance between the cutter and the point set is calculated and the collision points are selected by using the minimum distance algorithm, and the corresponding rotatable angle set is obtained. The safe angle which is larger than any other angles in this angle set is selected to determine the collision-free cutter orientation. The results show that this method can quickly determine the region of collision detection, and generate an interference-free tool path.

Key words: complex tunnel part, cutter orientation, critical constraint, five-axis end milling, interference