A 3D Numerical Analysis of the Chip Segmentation Mechanism and the Side Burr Formation During the Ti6Al4V Alloy Machining

Abstract

A 3D finite element modeling of the orthogonal turning process was curried out in the current study. It aims to carefully investigate the mechanisms controlling the chip segmentation and the crack propagation direction in the case of the Ti6Al4V machining. Coupled temperature-displacement numerical simulations were performed in the software Abaqus®/Explicit, under different cutting conditions. The instantaneous distribution of numerical thermomechanical variables along the width of cut was investigated. High plastic strains, temperatures and damage were predicted in the median plane of the workpiece, mainly in the shear bands around the tool tip vicinity. Whereas, a reduction of their values was noted while moving towards the chip sides and its upper surface. The 3D numerical simulations pointed out that the orthogonal machining resulted in an increase of the chip width, in addition to the material flow along the X and Y directions. The quantitative analysis of the side burr formation highlighted its sensitivity to the cutting conditions. The definition of high feed rates resulted in pronounced material flow in the workpiece edges, thus the modeling of wider chip. The present study concluded that the chip segmentation is a 3D mechanism. In addition, it pointed out the limitations of the 2D numerical simulations, as well as the inadequacy of the plain strain hypothesis, even in the case of the orthogonal machining.