Thermocouple Fixation Method for Grinding Temperature Measurement

A new thermocouple fixation method for grinding temperature measurement is presented. Unlike the conventional method using a welded thermocouple, this new method uses epoxy for affixing the embedded thermocouple within a blind hole in the workpiece subsurface. During grinding, the thermocouple junction is exposed and bonded to provide direct contact with the ground surface by the smearing of the workpiece material. Experiments were conducted to evaluate this simplified thermocouple fixation method including the effect of thermocouple junction size. Heat transfer models were applied to calculate the energy partition for grinding under dry, wet, and minimum quantity lubrication (MQL) conditions. For shallow-cut grinding of cast iron using a vitreous bond aluminium oxide wheel, the energy partition using a small wheel depth of cut of 10 mu m was estimated as 84% for dry grinding, 84% for MQL grinding, but only 24% for wet grinding. Such a small energy partition with wet grinding can be attributed to cooling by the fluid at the grinding zone. Increasing the wheel depth fo cut to 25 mu m for wet grinding resulted in a much bigger energy partition of 92% which can be attributed to fluid film boiling and loss of cooling at the grinding zone.