Influences of Cutting Speed and Material Constitutive Models on Chip Formation and their Effects on the Results of Ti6Al4V Orthogonal Cutting Simulation

Nithyaraaj Kugalur-Palanisamy,Pedro-José Arrazola,Edouard Rivière-Lorphèvre,François Ducobu

doi:10.25518/esaform21.2424

Abstract

The highly used Ti6Al4V alloy is a well know hard-to-machine material. The modelling of orthogonal cutting process of Ti6Al4V attract the interest of many researchers as it often generates serrated chips. The purpose of this paper is to show the significant influence of cutting speed on chip formation during orthogonal cutting of Ti6Al4V along with different material constitutive models. Finite element analyses for chip formation are conducted for different cutting speeds and are investigated with well-known Johnson-Cook constitutive model, a modified Johnson–Cook model known as Hyperbolic Tangent (TANH) model that emphasizes the strain softening behavior and modified Johnson-Cook constitutive model that consider temperature dependent strain hardening factor. A 2D Lagrangian finite element model is adopted for the simulation of the orthogonal cutting process and the results from the simulations such as calculated forces, chip morphologies are analyzed and are compared with the experimental results to highlight the differences. The results analysis shows that, the temperature in the secondary deformation zone is directly proportional to the cutting speed.

Highlights

The Ti6Al4V one of the most widely used titanium alloy
The RMS value of cutting force from all Johnson–Cook Constitutive Model (JC) and Johnson–Cook model by HOU (JC-Hou) numerical models considered in this study show as decreasing trend with increase in cutting speed, Whereas JC-Calamaz model shows an increasing trend with increase in cutting speed
Influences of cutting speed ranging from 30 m/min to 75 m/min with material constitutive models such as JC and modified JC constitutive material (JC-Hou, JC-Calamaz) on chip formation by numerical simulation are investigated and compared with the experiments conducted for uncut chip thickness of 60 μm

Summary

Introduction

The Ti6Al4V one of the most widely used titanium alloy The machining of this expensive alloy remains a major production industry concern because of the poor machinability characteristics. The Finite element modelling is widely employed by researchers [1] to reduce the experimental costs. Due to many factors that affect the machining, the finite element modelling of machining is a very complex process, often limited to the simplified orthogonal cutting configuration. A definitive constitutive model is always a principal factor in developing a finite element model [1]. Many material constitutive models have been developed in the recent years. Because of their simplicity and lucidity empirical models are widely considered

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Conclusion