Molecular dynamic simulation of tool groove wear in nanoscale cutting of silicon

Tool wear is one of the bottlenecks that decrease the machinability of hard and brittle materials in single point diamond turning (SPDT). Specifically, a microgroove generated on the cutting edge is an important character of tool wear, which leads to the formation of subcutting edges and facilitates the ductile to brittle transition in machining. However, the mechanism of the groove wear influence on the machined workpiece, especially the subsurface damage, is not clear just by the experimental investigations. In this paper, molecular dynamic simulations were carried out to explore the influence of groove wear on workpiece subsurface damage in SPDT of single crystal silicon. The propagation of grooves was also investigated by discussion of the stress and temperature distribution on the cutting edge. The Weierstrass-Mandelbrot function was adopted to set up groove wear on the tool flank face. It is concluded that grooves improve the atomic flowing ability and the plastic deformation in the workpiece. Moreover, the grooves can also cause polycrystal transition in the workpiece subsurface. The thickness of the subsurface damaged region is increased when groove wear becomes severe. This study contributes to the understanding of the details involved in the interaction between tool groove wear and workpiece, which is advantageous to improve the machined surface quality.