Analysis of the effect of tool geometry on the cutting process of polycrystalline Fe-Cr-W alloy based on molecular dynamics simulation

Abstract

In order to study the influence of tool geometry on the machining mechanism of alloy tool steel in the process of ultra precision turning, the polycrystalline molecular dynamics model of alloy tool steel is established with Fe, Cr and W, and the molecular dynamics model of tool is established with B and N. Four potential energy functions, Tersoff, EAM, Morse and L-J, are used to characterize the interaction between atoms in the model. The effects of tool geometry on hydrostatic stress, cutting force, cutting temperature and amorphous atoms in the turning process are analyzed. Research indicates:(1) Hydrostatic stress is mainly concentrated in the contact position between the tool tip and the workpiece, and it is compressive stress; (2) Cutting forces fluctuate and are significantly affected by tool geometry; (3) The cutting heat of about 1000K is concentrated in the chip, and the tool clearance angle has a great influence on the cutting temperature. (4) Amorphous atoms are formed at the chip location and the machined surface, and eventually turn into chips and the metamorphic layer of the machined surface.