Three-dimensional finite element modelling of high-speed milling of Inconel 718

The paper details research and development of a three-dimensional finite element (FE) model to simulate the ball nose end milling process using a commercial Lagrangian based code, ABAQUS Explicit. An elastic plastic constitutive relationship was employed for the Inconel 718 workpiece material, which took account of inertia, strain hardening, strain rate and temperature on the material's flow stress. Associated yield stress behaviour was determined experimentally using an elevated strain rate and temperature compression testing (up to 100s(-1) and 850 degrees C respectively), with the former subsequently extrapolated to the levels encountered in metal cutting. Ball nose end mill geometry was based on commercial tools and was created externally on a computer aided design (CAD) system and imported into the FE domain. Different cutting speeds were simulated with chip shape, cutting forces and temperature results detailed for the initial cut. Resultant cutting forces were found to be essentially constant across the range of speeds simulated, while average cutting temperatures increased with cutting speed, although not dramatically, both of which agreed with trends from experimental work.