Multi-objective Optimization of Double-Jet MQL System Parameters Meant for Enhancing the Turning Performance of Ti–6Al–4V Alloy

This paper mainly focuses on determination of optimum minimum quantity lubrication (MQL) parameter settings due to enhance the machinability of Ti–6Al–4V alloy, which is an area of huge concern for industrial production and academic research around the globe. MQL is an eco-friendly cooling method, which can be employed during machining Ti–6Al–4V alloys. In this work, a highly efficient MQL system has been developed by appropriate selection of various parameters like nozzle diameter, angle of impingement, oil flow rate, air pressure, etc., for enhancing the turning machinability of Ti–6Al–4V alloys. Cutting temperature, cutting force, and surface roughness have been considered as machinability criteria, where minimization of these responses was desirable. An experimental investigation has been designed by Box–Behnken design of experiments and carried out for turning Ti–6Al–4V alloy by carbide insert under double-jet MQL. Empirical models were developed for the process responses by response surface methodology. By employing ANOVA statistics, all the predictive models were found significant and highly acceptable with more than 90% of R². MAPE for the temperature, force, and roughness were found to be 3.93%, 1.27%, and 5.78%, respectively, when model responses were compared with experimental responses. As a final point, the desirability function approach has been used to find out the suitable combination of coolant application parameters which were nozzle diameter of 0.5 mm, primary nozzle angle of 20°, primary nozzle angle of 15°, air pressure of 20 bar, and oil flow rate of 50 ml/h with composite desirability value of 0.8301.