Effects of lubrication on friction and heat transfer in machining processes on the nanoscale: a molecular dynamics approach

MP Lautenschlaeger and S Stephan and MT Horsch and B Kirsch and JC Aurich and H Hasse, 11TH CIRP CONFERENCE ON INTELLIGENT COMPUTATION IN MANUFACTURING ENGINEERING, 67, 296-301 (2018).

DOI: 10.1016/j.procir.2017.12.216

Working fluids play an important role in machining processes. They serve twofold: On the one hand, they reduce the friction and thus weaken the generation of heat in the machining process. On the other hand, the working fluid cools the workpiece and the tool, acting as a heat sink. Both functionalities are investigated in the present work for a nanometric machining process by means of molecular dynamics simulations. The action of the tip of a cutting tool on a workpiece is studied both with and without working fluid. The Lennard-Jones truncated and shifted model is used for describing all interatomic interactions. The simulation results show that even in the presence of the working fluid, the tip of the cutting tool and the workpiece are mostly in direct contact during the machining process, i.e. the initially present fluid molecules are squeezed out of the contact zone. The work that is needed for the nanometric machining process is not significantly reduced by the fluid, but the coefficient of friction is. This results from a reduction of the normal force acting on the cutting tool. As expected, the working fluid has an important influence on the heat transfer during the nanometric machining process. Accordingly, mechanical quantities depend weakly on the solid-fluid interaction energy while the thermal quantities are more significantly influenced. The results of the study give insight in nanoscale phenomena in the contact zone between the tip of a cutting tool and the workpiece which cannot be studied experimentally. (C) 2017 The Authors. Published by Elsevier B.V.

Return to Publications page