Mechanism analysis and prediction of bull-nose cutter wear in multi-axis milling of Ti6Al4V with TiAlN coated inserts

Abstract

Cutter wear is an unavoidable issue during the milling of difficult-to-machine materials such as Ti6Al4V, which severely affects cutting performance and surface quality. Especially in multi-axis milling, the complex and irregular contact area between cutter and workpiece increases the difficulty of wear prediction. This paper proposes a flank wear prediction model of bull-nose cutter in the multi-axis milling process of Ti6Al4V with TiAlN coated inserts. The cutter workpiece engagement (CWE) zone is analyzed and the wear contact length of cutting edge is obtained, which reveals the uneven distribution characteristics of flank wear. After that, by analyzing the geometric profile properties of cutter wear in multi-axis milling, abrasive and adhesive wear, a flank wear prediction model that takes coating hardness and cutting temperature model into account is established. The proposed model is calibrated and validated by the multi-axis milling experiment of Ti6Al4V with TiAlN coated inserts. The results show that the novel wear model has high accuracy with an average percentage error of 12.76 % and can accurately and quickly predict flank wear in multi-axis milling of Ti6Al4V. Finally, the cutter wear mechanism and chip formation are analyzed, which show that the main wear mechanism is abrasive wear and adhesive wear, and there was no obvious oxidation wear.