Performance evaluation of cryogenic cooling in reaming titanium alloy

Removal of materials in metal cutting operations through drilling and reaming of hard materials is a difficult process. Wear of the tool and high cutting zone temperature have big effect on it. In this study, experiments have been carried out in a reaming operation on titanium alloy material under flood and cryogenic LN2 cooling separately. Cutting speed, feed rate, and hole depth (constant) are the three input variable parameters. Torque (Mt), thrust force (Ft), cutting temperature (T), quality of the hole, surface roughness (Ra), and chip morphology are the output parameters. In both cooling conditions, each of the nine experiments based on orthogonal array (OA) L9 were conducted under both cooling conditions. Based on the results obtained, cutting temperature was reduced by 12–21%, thrust force reduction is 17–32%, and torque reduction is 7–30% in cryogenic LN2 cooling. Surface roughness is increased by 4–15% and hole quality (circularity and cylindricity) parameters are affected in cryogenic LN2 cooling with respect to flood cooling. Better chip breaking was found in both flood and cryogenic LN2 cooling. No drastic changes were observed in microstructure under both cooling conditions.