The effects of liquid-CO2 cooling, MQL and cutting parameters on drilling performance

An investigation is made into the effects of liquid carbon dioxide (LCO2) cooling, minimum-quantity lubrication (MQL) and cutting speed in drilling. Experimental measurements of torque, thrust force and temperature are made over a wide range of process and operating conditions. The resulting empirical models are used to quantify the individual contributions of the controlled parameters on drilling performance, and to facilitate temperature-based process optimization. Of particular interest is the need to carefully adjust the LCO2 flow rate for any combination of MQL flow rate and cutting speed. The optimization is validated both in simulation and actual drilling tests.