A 3D Finite Element Study on Material Flow Under the Cutting Edge in Hard Milling

A 3D finite element model of hard milling has been created to have a deeper insight into some key issues. The model illustrates the effects of milling insert geometry on ploughed depth, material flow, transition from ploughing to cutting, and stresses and temperatures in the subsurface. Different ploughing depths from 0.6 μm – 3.0 μm are used to study the effects. The Johnson-Cook constitutive equation is used to model the plastic behavior of workpiece material AISI H13 steel (50±1 HRC). Surface and subsurface transient stresses and temperatures during ploughing show similar characteristics except the magnitudes. Ploughing depth of 1.8 μm corresponding to stagnation angle 35° is observed to be the threshold minimum uncut chip thickness at which transition from ploughing to cutting takes place. The material flow pattern with pile-up characteristics in front of the tool rake face is presented.