Wear Estimation of Coated Tools Using XFEM / Level Set Function

Overview & Synopsis

In these last years, it has become common to improve the wear resistance of cutting tools, especially in high-speed machining by depositing single or multilayered coatings on their surface. During cutting process, high pressure (about 1 GPa) and temperature (about 1000 °C) generated at the tool-chip interface affect drastically the cutting zone inducing then damage and several wear modes as cracking, abrasion, and delamination of the coating. Studying the behavior of coatings and their various modes of degradation leads to a better understanding of their impact on the cutting tool life and the machining operation under optimal conditions. The main objective of this work is to perform an accurate model to predict the tool wear of coated inserts. The Usui wear law was used to simulate the tool wear process for the coating and the substrate. The coupled XFEM/Level Set Function was performed: (i)-to avoid distortion of the mesh when the worn tool profile is updated, (ii)-to facilitate the material interfaces representation of the substrate/coatings system implicitly via the level set function and finally (iii) to reduce the CPU calculation time. Indeed, the mesh size is not dependent on the coating thickness with this approach. Thanks to additional enrichment functions in the XFEM formulation, the continuity of the displacement and temperature fields at the substrate/coating interface is insured. Besides, several cutting tests have been performed to validate the proposed model.