Prediction of Chip Morphology and Cutting Force during Prestressed Cutting of TC4

Chip morphology plays a predominant role in determining machinability and tool wear during the machining of titanium alloys. Chip formation process in prestressed cutting of titanium alloy TC4 was numerically explored via the finite element method. Crack initiation during the chip segmentation was realized by using a ductile fracture criterion which based on the strain energy. Effect of prestress on cutting force and chip formation as well as Mises stress distributions were revealed. The results indicate that chips show the similar characteristic of continuous and regular serrated shape, which is not affected by prestress. Initial stress distribution of workpiece was changed by prestress, which correspondingly leads to the alteration of stress distribution in the subsurface layer. The generated cutting force curves share the same average amplitude and analogous rhythm, which correspond to the chip forming process respectively.