Triangle Mesh Based In-Process Workpiece Update for General Milling Processes

Abstract

A new methodology for modeling and updating the in-process workpiece geometry in milling is presented in this paper. The methodology is developed for general milling processes, in which the cutter can be any shape and follow any tool path trajectory even with self-intersections. And the in-process workpiece is updated with retained sharp features. The associated procedure starts by modeling both the cutter and the workpiece as closed manifold triangle meshes. The mesh model of the cutter swept volume is then generated from repeatedly sampled mesh vertices of the cutter along its trajectory using the ball-pivoting algorithm. The workpiece is updated by a subtraction Boolean operation between the workpiece and the cutter swept volume. An octree space partitioning algorithm is adopted in order to efficiently obtain the exact triangle-to-triangle intersection points. As the last step, a filling operation is performed around the intersection points to establish the closed manifold updated workpiece geometry. Several case studies have been performed to demonstrate the effectiveness of the proposed methodology.