Numerical modeling and simulation of macro- to microscale chip considering size effect for optimum milling characteristics of AA2024T351

Abstract

This research work deals with the numerical modeling and analysis of macro- to microscaled milling of a strain rate-sensitive alloy AA2024T351. The milling computations of a semicircular slot are performed in Abaqus/Explicit by employing the Johnson–Cook thermo-elasto viscoplastic material damage model. The Coulomb friction model is applied at the contact interfaces of work piece and cutting tool. Due to the simultaneous effect of cutting feed and angular speed (ωr), the geometry of uncut chip is modeled with variable section thickness to adapt the trochoidal path. The configuration of the uncut chip undertakes the macro- to micromilling effect. This research effort uniquely explains a comprehensive modeling and milling computations at macro- to microscales to identify the imperative milling characteristics. The presented formulation in form of the modified Johnson–Cook constitutive equation explains the size effect during micromilling. A parametric sensitivity analysis is performed with four different cutting speeds (500, 600, 700, and 800 m/min) and two contact friction coefficients (0.2 and 0.3) while keeping the feed rate constant (0.2 mm/teeth). It was observed that cutting speed and contract friction coefficient play a pivotal role in cutting reaction force and chip–tool interface temperature. A temperature in the range of 141–167 °C is predicted with different cutting speeds. The percentage deviations of the simulated cutting forces from the published experimental results are found promising. The estimated deviation may be because of compromising some imperative factors in numerical model, such as cutter vibrations, tool wear effect, tool run-out, and limitations, to develop an exact trochoidal trajectory.