Abstract: The cutting performance, cutting temperature and tool wear are influenced by the tool-chip stress distribution. The molecular dynamics simulation approach is performed to investigate the tool-chip stress distribution and friction phenomena in nano-machining of monocrystalline silicon and copper materials. Tersoff potential function is employed to model the inter-atomic force among silicon atoms, and EAM potential function is used to model the interatomic force between copper atoms, and Morse potential function is used to model the interatomic force between the workpiece atoms and cutting tool atoms. Both the relations between the contact lengths of tool-chip interface and the cutting distance, and the influence of the tool rake angle on the stress distributions are analyzed. The atom motion and interaction along the tool-chip interface are given to explain the stress distributions along tool-chip interface in the nano-machining process. The normal forces in copper exhibit a peak near the tool edge, and gradually decrease toward zero as the contact ceases to exist, while the normal forces in silicon present regular fluctuations along the tool-chip interface. The friction force in both copper and silicon all show a negative value near the cutting edge. After that, the friction force in copper reaches the maximum at a distance of two-thirds of the contact length and then gradually decreases to zero.

Key words: Atomistic machining, Single crystalline copper, Single crystalline silicon, Stress distribution