Study on coolant-induced hydrodynamic pressure in contact zone while deep grinding with CBN wheels

Abstract

ABSTRACTThe use of coolant has been considered an effective way to avoid workpiece burn in the grinding process. Hydrodynamic pressure induced by coolant in the contact zone is always measured to characterize the coolant condition in the contact zone. In this study, grinding experiments with a cubic boron nitride wheel were first performed to determine the evolution of hydrodynamic pressure during the grinding process. The experimental results showed that when burn happened, hydrodynamic pressure was at a low level and decreased gradually while the temperature and power signals fluctuated sharply. A theoretical calculation model and a 3D air–liquid two-phase numerical simulation model were subsequently constructed to predict the hydrodynamic pressure. Both theoretical calculation and numerical simulation results showed that the hydrodynamic pressure in such a case is in inverse proportion to the gap distance between the wheel and the workpiece. The theoretical calculation results are higher than the numerical simulation results. Furthermore, the experimental results correspond to the results of the 3D air–liquid two-phase simulation, which confirms the validity of this simulation. This article presents an accurate approach to predict hydrodynamic pressure, which provides an effective analytical method of studying and avoiding workpiece burn.