Influence of the coating residual stresses on the tool wear

The use of PVD (Physical Vapor Deposition) coatings is one of the most common methods to improve the performance of the cutting tools, reducing the wear under heavy loads and high temperatures. 

A key aspect to increase the tool life is the control and development of the PVD process.In this work different turning inserts have been coated with two different coatings (ZrCN and TiN) and four different bias voltages (30, 120, 210 and 400 V). The residual stresses in the coated tools have been measured in the clearance face near tip of the tool zone using grazing incidence X-ray diffraction.In order to analyze the performance of the coated tools and the relation residual stresses-tool life, machining tests have been performed with two steel grades, AISI 1045 and AISI 4340. The results show that the tool wear is directly related to the residual stresses of the coatings, and these can be controlled by the bias voltage.