The development of special drills for high-efficient drilling austenitic stainless steel - Part I: Drill comparison and experiment research

Austenitic stainless steel is a kind of difficult-to-cut material widely utilized in various industry fields. But cutting tools is the uppermost obstacle in the application of high efficient and precise machining of austenitic stainless steel. Drill is the one of the most complicated universal cutting tools, whose geometry structure influences greatly on drilling performance. So the development of special drills is imperative for high-efficient drilling. This paper presented the optimal geometrical characteristics of the special drills, with 138 degrees point angle and 38 degrees helix angle, for high-efficient drilling austenitic stainless steel. The drilling performance has been evaluated completely and comprehensively through the experiments including measuring cutting deformation coefficient, thrust force, torque, cutting temperature near the cutting point, cutting tool life, drill wear mechanism and so on. The special drill indicated appreciated cutting performance during drilling austenitic stainless steel with high efficiency. Compared to the commercial available standard drill with 118 degrees point angle and 32 degrees helix angle, the cutting tool life of the special drill was 1.6 times of the standard drill and the special drill yielded good performance of chip evacuation, good wear resistance and great drilling quality.