Algorithm of global collision detection for machining freeform surfaces

The existed algorithms for global collision checking in free form surfaces machining have been analyzed, and a new efficient algorithm is proposed for collision checking in NC machining of freeform surfaces. First, an oblique cube convex hull of the freeform surface is applied to check whether there is intersection between the tool orientation and the oblique cube convex hull. If there is no intersection, it means the tool orientation is feasible. Otherwise, the detailed feasibility checking is developed to detect whether there is a global collision between the freeform surface and the tool orientation. Once there is collision, the tool orientation will be adjusted to avoid the global collision.