Investigation of Frictional Resistance in Nanometric Cutting by Molecular Dynamic Simulation

Abstract

Recently, the development of machine tools and sub-micron positioning control systems has brought the minimum thickness of ultra-precision cutting to less than 1 nm. The conventional continuum based method (FEM) becomes impossible to use for numerical analysis. As an alternative method, molecular dynamics (MD) method is significantly implemented in the field of nano-machining to investigate cutting mechanism. In this paper, firstly, molecular dynamics simulations of the nanometric cutting of single-crystal copper were performed applying a pin tool. The model was solved with both Morse and Embedded Atom Method (EAM) potential functions to simulate the interatomic force between the work piece and a rigid tool. The nature of material removal, chip formation, and frictional forces were simulated. In order to investigate the coefficient resistance (the ratio of the cutting force to the thrust force), some MD simulations also carried for various cutting velocity and cutting depths. The results show that the Morse potential and EAM method have some difference to model tool forces and frictional resistance. Also, surface properties and atomic displacement in each of these potential functions have some discrepancy. In addition, cutting and trust forces increase with the cutting velocity and the depth of cut, however the effect of cutting speed is not very significant. Finally the value of frictional resistance is not changed with similar tool for various cutting speeds.