Improving cutting performance of carbide twist drill combined internal cooling and micro-groove textures in high-speed drilling Ti6Al4V

Abstract

High-speed cutting technology has become the main direction of development of machinery manufacturing industry; however, the excessive temperature and sharp tool wear have greatly restricted the improvement of drilling speed. To reduce the cutting temperature and alleviate the severe friction and wear of the tool/chip and tool/workpiece interface, micro-groove textures were fabricated on the rake face and flank face of the carbide internal cooling twist drills by an Nd:YAG laser. Thus, two developed cutting tools were fabricated: (1) the internal cooling twist drills with textured rake-face (TF) and (2) the internal cooling twist drills with textured flank-face (TB). High-speed drilling experiments were carried out on Ti6Al4V using these developed tools, and the resulting friction and wear data were compared with those from the conventional one (NT). Results obtained in this work demonstrated the feasibility of fabricating micro-groove textures on internal cooling tool to improve the high-speed cutting performance. Moreover, the mechanisms for the effects of micro-textures fabricated on rake face and flank face were different. The micro-groove textures fabricated on the rake face can significantly increase the degree of chip curling, reduce the contact length at the tool/chip interface, and improve the chip breaking ability; while, the internal cooling abilities were significantly enhanced by the micro-textures fabricated on the flank face; thus, the effects on decreasing the drilling force and improving the anti-adhesive and abrasive wear properties were achieved.