Taguchi optimization of minimum quantity lubrication turning of AISI-4320 steel using biochar nanofluid

In this research work, the effect of minimum quantity lubrication (MQL) parameters on the material removal rate and surface roughness of AISI-4320 steel using biochar nanofluid in turning process was studied. The main aim of this present work was to optimize the process parameters of MQL turning process using Taguchi method. The turning process outputs such as material removal rate and surface roughness were measured and analyzed using gray relational grades to determine the process efficiency using biochar nanofluid. The study was conducted using Taguchi L9 orthogonal array followed by grey relational method. According to the analysis, the nanofluid concentration in minimum quantity lubrication was the most influencing process parameter with the lowest fluid flow rate to produce the highest material removal rate of 58.312 mm³/s and low surface roughness of 3.236 μm. The machining process parameter levels such as A₃B₁C₃ are found to be the promising process variable levels, where the highest material removal rate and lower surface roughness were produced. The SEM micrographs of the tool tip show a lower tool wear for machining with nanofluid of 2 wt.% biochar.