Optimization of Process Parameters based on Surface Roughness and Cutting Force in MQL Turning of AISI 4340 using Nano Fluid

The aim of this research work is focused on optimization of process parameters under Minimum Quantity Lubrication (MQL) using nano fluid in turning of AISI 4340. A study of effect of process parameters in turning of AISI 4340 under MQL condition with nano fluid (Multiwalled Carbon Nano Tube) on the cutting force generated and machined surface roughness is carried out. In the experiment conducted, five values of feed rate, three values of depth of cut, two values of spindle speed and tool nose radius respectively, are used. The chemical composition of the work material was tested using arc spectrometer and verified to be of grade AISI 4340. The test pieces were turned on a CNC lathe machine under MQL mode using nano fluid with different levels of process parameters by using full factorial design of experiment orthogonal array. The surface roughness of the machined surface was measured using surface measurement tester. Taguchi methodology was used to optimize process parameters. The results were analyzed using Analysis of Variance (ANOVA). From result analysis, it was found that, feed rate played a major role in producing lower surface roughness followed by depth of cut whereas spindle speed has least significance in producing lower surface roughness under MQL using nano coolant. It was observed that MQL with nano fluid (MWCNT) showed lowest surface roughness as compared to conventional flood system. Thus, with proper selection of process parameters under MQL mode with nano coolant, it is possible to achieve good surface roughness, reduce tool wear while maintaining the cutting forces and temperatures at reasonable levels.