MOLECULAR DYNAMICS SIMULATION OF NANOMETRIC CUTTING

Molecular Dynamics (MD) simulations of nanometric cutting of single-crystal copper were conducted to predict cutting forces and investigate the mechanism of chip formation at the nano-level. The MD simulations were conducted at a conventional cutting speed of 5m/s and different depths of cut (0.724-2.172nm), and cutting forces and shear angle were predicted. The effect of tool rake angles and depths of cut on the mechanism of chip formation was investigated. Tools with different rake angles, namely 0 degrees, 5 degrees, 10 degrees, 15 degrees, 30 degrees, and 45 degrees, were used. It was found that the cutting force, thrust force, and the ratio of the thrust force to cutting force decrease with increasing rake angle. However, the ratio of the thrust force to the cutting force is found to be independent of the depth of cut. In addition, the chip thickness was found to decrease with an increase in rake angle. As a consequence, the cutting ratio and the shear angle increase as the rake angle increases. The dislocation and subsurface deformation in the workpiece material were observed in the cutting region near the tool rake face. The adhesion of copper atoms to the diamond tool was clearly seen. The same approach can be used to simulate micromachining by significantly increasing the number of atoms in the MD model to represent cutting depths in the order of microns.