Investigation of nanoparticle-enhanced vegetable oils with minimum quantity lubrication on sustainable machining of titanium alloys

Titanium alloys require eco-friendly machining alternatives to hazardous conventional lubricants. This study investigates titanium machining using nanoparticle-enriched vegetable oils under minimum quantity lubrication. Cutting forces, surface roughness, and temperature are analysed with varying machining and lubrication parameters. Enhanced thermal conductivity and protective nanoparticle films promote efficient heat dissipation, reduced cutting temperature, smoother tool-workpiece interaction, and superior surface finish. Experimental results reveal cutting force initially rises with velocity due to work hardening, then decreases from thermal softening. Optimal lubrication pressure was 3 kg/cm2, while nozzle angle effects were nonlinear, peaking at 30° and minimising at 45°. Nanofluid-assisted MQL reduced cutting temperature by 15%-20% and significantly improved surface finish, with palm oil + MWCNT achieving up to 52% roughness reduction. Depth of cut dominated machining response, followed by feed rate and pressure. These findings highlight that Sustainable machining can be achieved using nanoparticle-based MQL oils.