Molecular Dynamics Simulation of Rubbing Phenomena in Ultra-Precision Abrasive Machining

This study aims to clarify the friction and wear phenomena, which are of great importance in abrasive machining with atomic-scale material removal, such as polishing of magnetic disk substrates and CMP of semiconductor substrates. Various phenomena that occurred when a well-defined copper surface rubbed by an extremely fine rigid diamond abrasive, such asthe sliding without removal and the atomic-scale wear, were analyzed using a molecular dynamics model, in which the abrasive grain was connected to a three-dimensional spring and the holding rigidity of the abrasive grain was taken into account. A series of simulations using different indentation depths clarified that the one- or two-dimensional atomic-scale stick-slip phenomenon in proportion to the period of atomic arrays of workpiece surface occurred in the sliding processes without atomic removal. The results also demonstrated that the period and amplitude of the fundamental stick-slip wave varied when accompanied with atomic removal due to the increase in normal load.