Numerical and Empirical Modelling of Machining-induced Residual Stresses in Ball end Milling of Inconel 718

Abstract

Machining induced residual stresses can be crucial for the performance and life of the end product. In this paper, a 3D numerical model and an empirical model for residual stresses prediction were built to evaluate the near-surface residual stresses in Inconel 718 under ball end milling conditions. A series of ball end milling experiments of Inconel 718 have been conducted and X-ray diffraction measurements have been utilized to obtain the test residual stress profiles. The comparison results reveal that the numerical model can give an efficient estimation of the residual stress state beneath the machined surface, but the accuracy of the simulation model still needs to be improved. On the basis of the measured residual stresses, an exponentially decaying cosine function was fitted using a particle swarm optimization method. For the purpose of predicting machining induced residual stresses with different cutting parameters, a prediction model based on cutting parameters was developed. A good correlation was observed between the experimental and the predicted results derived from the empirical model.