Finite element simulation of cutting process under the worn tool edge geometries

Finite element (FE) technique has been used extensively to have a deeper understanding on the mechanics of metal cutting and for process optimization. The accuracy of the model is dependent on both the highly non-linear material plasticity model and the simulated friction condition between contacting surfaces. Hence, majority of the predicted results were validated from direct or indirect experimental results. Measurement of cutting forces magnitude and temperature field are direct techniques to validate the model. Indirect methods are chip morphology and residual stresses measurement from the newly generated surface. In this paper, a unique indirect method is proposed to validate the accuracy of the FE model. This method predicts the tool wear rate by using the average contact pressure and interface temperature acquired from finite element simulation, as the inputs for the Usui’s tool wear rate equation. Orthogonal cutting experiments were performed in specific ranges of cutting speed and feed rate. The workpiece material used was AISI 1045 at 86 HRB, and tool material was uncoated carbide. Tool cutting edge geometry was analyzed in different steps of the cutting process, and worn edge geometries were obtained. The worn edge geometries were then used to build the FE cutting models. Based on the simulation results when the flank wear length increases, the temperature field prediction showed that the region of maximum temperature shifted from the rake face to the flank face region. The contact pressure increased substantially with cutting speed rather than feed rate. The predicted wear rate agreed well with experimental results. Using tool wear rate to predict the accuracy of the FE cutting model is limited to the orientation of the rake and flank face surfaces.