Some aspects of machining with negative-rake tools simulating grinding: a molecular dynamics simulation approach

Ultraprecision grinding, like ultraprecision machining, involves removal of material (or cut depths) of the order of a few nanometres or less. Consequently, the material removal by this process is denoted as nanometric cutting. In this paper, the results of the molecular dynamics (MD) simulation studies conducted over a wide range of negative-rake-angle tools to simulate grinding are presented. The variations in the cutting forces, specific energy (energy required for removal of unit volume of work material), nature of subsurface deformation and size effect with rake angle were investigated by comparing the MD simulation results with the experimental results published in the literature. An increase in the magnitudes of forces, the ratio of the thrust to the cutting force, the specific energy and the sub-surface deformation were observed with increase in the negative rake. The specific energy in nanometric cutting was found to be nearly an order of magnitude larger than in conventional cutting, strongly indicating a size effect that is commonly observed when the specimen size under consideration has submicrometre to nanometre dimensions.