Collision-free regions of tool posture in five-axis machining of blisk with a filleted end mill

In five-axis machining of blisk, the filleted end mill has attracted more and more attention because of its larger cutting width. However, it is still a hard work to find the tool posture without interference. In this paper, a method is proposed to solve the collision-free regions. Based on the visibility of free-form surface, a tool-surface tangent model of the filleted end mill is established. With the model, only critical points on profiles of checking surface are searched with a self-adapting step length and the corresponding critical vectors are calculated and mapped to construct the collision-free regions. Firstly, critical points on the boundaries are searched according to the given precision. Meanwhile, the corresponding critical vectors are calculated and some special searched points are selected as the endpoints of each profile. Then, the adjacent critical points are searched along the profile by adjusting iteratively with a self-adapting step length in the parameter domain one by one. During the search, the corresponding critical vectors are calculated too. After that, the critical vectors are mapped to construct the subinterval collision-free regions in two-dimensions. And a method is adopted to combine collision-free regions. This algorithm is finally verified with a closed blisk and compared with a referenced method. The results show that it can efficiently solve collision-free regions in five-axis milling of blisk with a filleted end mill.