Deformation and material removal mechanisms of nanometric cutting of silicon at different depths of cuts using molecular dynamics simulation

Abstract

ABSTRACT

The diamond tool with a rake angle of zero has been rarely studied, and the cutting mechanism in ultraprecision machining of brittle materials, such as silicon, is not well understood due to the varying cutting parameters involved. The use of this tool was investigated through molecular dynamics simulation to examine the material removal mechanisms in silicon nanometric cutting at different depths of cut. Simulations were performed using the large-scale atomic/molecular massively parallel simulator with the Tersoff potential function Mechanisms of chip formation and material removal were analysed at three different depths of cut (2 nm, 3 nm, and 4 nm). The study reveals that the structural and phase transformations in silicon are caused by high-pressure phase changes and dislocation activity leading to chip formation and material removal. Machining at a lower depth of cut results in a machined surface with less subsurface damage. For all depths of cut, the material removal mechanisms operate in a ductile mode, except at 4 nm, where a combination of ductile and brittle (cleavage) modes is observed on the machined surface. To ensure a ductile machining mode with this tool geometry, the depth of cut should be significantly smaller than the cutting-edge radius of the diamond tool to achieve a high-quality surface finish.