Studies on the behaviour of the green particulate fluid lubricant in its nano regime when machining AISI 1040 steel

Significant advances, both practical and theoretical, have been made in understanding the behaviour of engineering materials when machining at higher cutting conditions. Nano-integrated manufacturing is a subject of immense interest for various sustainable engineered systems. Metal removal processes involve the generation of high cutting forces and temperatures. The use of proper lubricant to reduce forces and temperatures and to improve total cutting phenomena overall is an important aspect. The present investigation analysed a green, petroleum-free lubricant that is produced by mixing two environmentally benign components, canola oil and nano-crystalline boric acid. To study the influence of variation of nano-level boric acid particle size and its weight percentage on the performance of the proposed green particulate fluid lubricant, various turning tests were conducted on AISI 1040 steel using tungsten carbide inserts. Variations in cutting forces, tool temperatures and surface roughness were studied. The experimental results revealed that both cutting forces and tool temperatures increased as the boric acid particle size decreased. The surface quality of the machined surface was reduced as the solid lubricant particle size was reduced to the nano-level. Interestingly, reductions in both cutting force and tool temperature were observed as the boric acid weight percentage decreased, tending towards the pure canola oil-based machining results. The surface quality of the machined surface was also improved as the volume fraction of boric acid was decreased.