Prediction of PCBN tool life in hard turning process based on the three-dimensional tool wear parameter

The ideal scenario for the implementation of a machining process is to be able to predict tool performance without the need to conduct practical experiments. However, in an industrial environment, each set of machining conditions is unique, since the machine-tool conditions, machined material, cutting tool, and fixture system can vary. This can lead to differences between the predicted values and practical results. In this context, the aim of this research was to show and discuss a tool performance test methodology and a tool-life prediction model using the three-dimensional (volumetric) wear parameter W_RM (volume of material removed from the tool) applied to hard turning with PCBN tools. The wear parameter W_RM is measured at the beginning of the tool life (up to 25%) by focus variation microscopy (FVM). The tool wear rate (WR_RM) is then calculated based on the ordinary least squares (OLS) method, and the tool life is estimated (TW_RM) adopting the volume of material removed from the tool (WR_Mmax) as the criteria for the end of tool life. The tool-life model developed was capable of predicting the tool life with errors below 4% at the higher values of cutting speed adopted (v_c = 150–187.5 m/min), that is, the cutting speeds applied industrially. The methodology adopted and the model developed represent a significant time reduction in the experimental machining tests, streamlining the research and development of the cutting tool grades, as well as the machining process optimization.