Mechanistic Cutting Force Model and Specific Cutting Energy Prediction for Modulation Assisted Machining

Abstract

This paper presents a mechanistic model for analytical cutting force and specific energy prediction for modulation assisted turning. Kinematics of the process is used to analyze the cut surface topography and derive the uncut chip thickness variation for various modulation parameters. It is found that uncut chip thickness is governed by successive spindle rotations and can be represented in the form of trigonometric functions. The cut and no-cut phase durations are controlled by the modulation frequency and amplitude. Cutting (machining) forces are predicted based on the orthogonal cutting mechanics. The thin shear plane angle is predicted considering oscillations in the cutting velocity, resultant effective rake angle and by employing the well-known Minimum Energy Principle (MEP). In order to accurately predict the shear forces, length of the shear plane is estimated directly from the uncut and cut part surface geometries, which incorporates waviness of the surface. Analytical chip thickness predictions and proposed cutting force models are combined used to predict the specific cutting energy in MAM. Experimental results verify accuracy of developed force models in estimating cutting forces and energy in orthogonal modulated assisted turning of Al6061 T6511.