Temperature and energy partition in minimum quantity lubrication-MQL grinding process

Abstract

An investigation is reported of the temperature and energy partition in grinding with minimum quantity lubrication (MQL) technique. Temperature distributions were determined in the subsurface of a hardened 100Cr6 steel workpieces through measuring by means of an embedded thermocouple during grinding in dry, MQL and fluid environments. The experiments were carried out with Al2O3 and CBN wheels. The energy partition to the workpiece was estimated using temperature matching. It is shown that the energy partition, and consequently the contact zone temperature, depends on the type of abrasives and coolant–lubricant conditions. For MQL grinding with Al2O3 abrasive wheels, the energy partition varies in the range 73%–77%. However, the energy partition is about of 82% for dry grinding. In fluid grinding with Al2O3 wheels, cooling by the fluid at the contact zone reduces the energy partition to less than 36%. For dry and MQL grinding with CBN superabrasive wheels, the energy partition is respectively about 52% and 46% due to the high thermal conductivity of the CBN abrasive. However, this can be reduced to 14% for grinding with CBN wheel and cooling by the fluid.