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Abstract: A finite element model has been developed with Abaqus/Explicit to model the orthogonal cutting of Ti6Al4V. Experiments were carried out to validate its results. The experimental cutting conditions are the same as those used in the finite element model. They lead to the production of a saw-toothed chip, either numerically or experimentally. The comparison of the model results shows that the difference with the experimental RMS cutting force value is quite large (about 40%). Both chips morphologies are similar although the teeth of the simulated one have smaller valleys and lengths. The numerical model could therefore be improved. The aim of this paper is to study the influence of the material behavior law and the damage value on the model results, in order to get closer to the experimental results. It shows that the difference between numerical and experimental cutting forces reduces drastically (it becomes of the order of 2%) for stresses obtained with the modified behavior law similar to those observed in the literature. The teeth of the chip have a larger valley and are therefore closer to the experimental chip. These improvements do not interfere with the physics of the saw-toothed chip formation, which is still the same as the experimental one. An important point is that it turns out that the influence of the material behavior law and of the damage value are almost decoupled within the limits of the variations selected. Indeed, the material behavior law controls the level of the cutting force while the damage value acts mostly on the morphology. [Copyright &y& Elsevier]

Numerical modeling of metal cutting is a complex problem involving many nonlinear and coupled phenomena (high speed, large strains, large strain-rates, heat generation, etc.). Due to the large deformations, the mesh of the workpiece is often highly distorted. When it does not ends prematurely the computing, it slows it down and decreases the confidence in the results. Many formalisms are encountered in the literature to model the orthogonal cutting process, each with their pros and cons, more or less significant. This paper introduces the Coupled Eulerian-Lagrangian (CEL) formulation, in which the workpiece is described by the Eulerian formulation and the tool by the Lagrangian one. The comparison with experimental results and an Arbitrary Lagrangian-Eulerian (ALE) model with pure Lagrangian boundaries shows that the chip morphology and the cutting forces are well predicted by that new model. The absence of mesh deformation in the part does not decrease the stable time increment and therefore does not slow down the computing, which is competitive compared to the reference ALE model. This also increases confidence in the results given by the CEL model and opens new possibilities in the modeling of metal cutting. [ABSTRACT FROM AUTHOR]

The titanium alloy Ti6Al4V, although widely used in machining, is a hard-to-machine material, particularly due to the production of saw-toothed (or segmented) chips. The phenomena leading to this kind of chips are still an ongoing problem in the current literature, as well experimentally as numerically. An experimental orthogonal cutting setup on a milling machine is presented as a benchmark to validate finite element models. Its ease of implementation and near-to-zero cost should enable it to be used for any material, as long as the cutting speed is achievable by the feed rate of the machine. In addition to the study of chip formation, this setup could also allow to carry out long, although interrupted, machining tests to analyze tool wear. A numerical finite element model is then introduced to model the chip formation in the same cutting conditions. The comparison of the numerical results with the experiments shows that the level of the forces is mainly influenced by the material constitutive model, while the chip morphology is mostly impacted by the chip separation criterion. Either experimentally or numerically, the mechanism leading to the formation of a Ti6Al4V saw-toothed chip, for the cutting conditions of this study, is the conjunction of the adiabatic shear band in the primary shear zone, followed by the propagation of a crack into it. [ABSTRACT FROM AUTHOR]