Wear behavior of coated tools in laser assisted micro-milling of hardened steel

This paper presents a comparison of the performance of different cutting tool coatings for Laser Assisted Micro-Milling (LAMM). A thermal model is used to predict the temperature rise in the material removal surface which helps in analyzing the severity of the thermal conditions experienced by the cutting tool in LAMM. Machining experiments are then carried out to evaluate the wear behavior of different commercially available (TiCN, TiAlN) and customized coated tools (TiSiN, Al₂O₃, Al₂O₃+ZrN). These coatings were selected since they have the capability to withstand the temperatures experienced in LAMM. The results of micro-milling experiments indicate that commercially available coatings like TiCN perform poorly due to their inferior adhesion characteristics with the base material. Delamination is found to be the principal wear mechanism of TiCN, TiSiN, and Alumina (Al₂O₃) coated tools for the conditions investigated in this study. In addition, the results indicate that the wear performance of TiAlN and Al₂O₃+ZrN coated tools is superior.