Analytical modeling of chip geometry and cutting forces in helical ball end milling of superalloy Inconel 718

The ball end milling process, commonly used for generating complex shapes, involves continuous variation in the uncut chip dimensions, thereby introducing increased complexities in the cutting force prediction. Therefore, usually a mechanistic modeling approach is recommended. This paper however, presents an analytical approach, to predict chip dimensions followed by instantaneous shear angle in ball end milling of superalloys. Subsequently, the cutting forces are predicted considering strain, strain rate, and temperature dependence of work material shear strength by applying Johnson–Cook material model. The proposed analytical model evaluates the uncut and the cut chip dimensions including chip length, width and thickness. The instantaneous shear angle evaluated using the models, is a function of cutter rotation, instantaneous cutter radius, helix angle, and so on. The cutting forces prediction in the framework of oblique cutting theory, takes into account the ploughing forces acting on the cutting tool edges. It is observed that the analytical models for predicting chip dimensions and the cutting forces in X- and Y-directions match well with the corresponding experimental values.