Selection of optimal MQL and cutting conditions for enhancing machinability in turning of brass

Minimum quantity of lubrication (MQL) in machining is an established alternative to completely dry or flood lubricating system from the viewpoint of cost, ecology and human health issues. Hence, it is necessary to select proper MQL and cutting conditions in order to enhance machinability for a given work material. The present work aims at determining the optimum amount of MQL and the most appropriate cutting speed and feed rate during turning of brass using K10 carbide tool. Taguchi technique with the utility concept, a multi-response optimization method, has been proposed for simultaneous minimization of surface roughness and specific cutting force. The experiments were planned as per Taguchi's L9 orthogonal array with each experiment performed under different conditions of MQL, cutting speed and feed rate. The analysis of means (ANOM) and analysis of variance (ANOVA) on multi-response signal-to-noise (S/N) ratio were employed for determining the optimal parameter levels and identifying the level of importance of the process parameters. The optimization results indicated that MQL of 200 ml/h, cutting speed of 200 m/min and a feed rate of 0.05 mm/rev is essential to simultaneously minimize surface roughness and specific cutting force.