Finite Element Modeling of Three-Dimensional Milling Process of Ti-6Al-4V

Abstract

Titanium and its alloys are widely used in aerospace and medical implants due to their excellent mechanical and chemical properties. Titanium is light, strong, corrosion resistant, and biocompatible; however, it has poor machinability. The low thermal conductivity and high strength result in large cutting forces and elevated temperatures during machining, as well as a reduced tool life and a poor machined surface. The current work is based on a 3D finite element method (FEM) modeling of dry milling processes on a Ti-6Al-4V workpiece. The FEM solver Abaqus Explicit (R) was used with the Johnson-Cook plasticity model to describe the deformation of the workpiece. Experimental work was carried out to validate the simulated cutting forces and chip morphology; the error in the predicted cutting forces in feed and normal to feed direction was in the range of 1-34%, which was mostly within the experimental variation. The measured chip morphology showed good agreement with the simulated data in terms of the chip size and shape. A parametric study of the effect of the machining parameters on the cutting forces was carried out, where the cutting speed, depth of cut, and feed rate were varied, and the radial, tangential, and axial cutting forces were measured. An increase in the feed rate from 50 mu m/tooth/rev to 200 mu m/tooth/rev resulted in an increase in the tangential and axial forces of 143% and 239%, respectively. An increase in the depth of cut from 50 mu m to 200 mu m resulted in an increase in the tangential and axial forces of 237% and 100%, respectively. We found that increasing the feed rate was preferable to increasing the depth of cut, as it led to a smaller tangential force.