Geometric Approaches for Reducing Burr Formation in Planar Milling by Avoiding Tool Exits

One of the most effective methods for reducing milling exit burrs is to prevent the tool from exiting the workpiece. Exit here refers the condition in which a cutting edge is moving out of the workpiece while removing material. Only entrance burrs can occur under this circumstance, which are usually considered burr-free. This study proposes a set of geometric algorithms for avoiding tool exits in planar milling. Two distinct approaches are developed for tool path planning of 2-D polygons. The first approach generates exit-free tool paths by offsetting the workpiece edges with appropriate widths of cut. The second one adjusts tool positions locally on given tool paths. In addition, a two-stage algorithm is designed for 2-D free-form contours. The cutter locations causing the tool to exit the workpiece are first detected; then a heuristic scheme is applied to generate new cutter locations with no tool exits. Experimental results show that edge quality is significantly improved using the proposed methods. This work provides a feasible way for suppressing burr formation in an automatic manner, and thus reduces the need for deburring.