Role of minimum quantity lubrication in hard turning using vegetable oil-based molybdenum disulphide–carbon black hybrid nano-fluid

Abstract

Machining hardened steel components has garnered significant interest because of its wide application in the automotive, press-tooling, mold-die, gear, bearing, and aerospace sectors. Working with hardened steels provides numerous advantages, but optimizing efficiency is difficult due to the high levels of heat, friction, cutting forces, and tool wear that can compromise the quality of the products. Dispensing conventional cutting fluids while machining is an effective technique but it has significant effects on both environment and human health. Therefore, it is essential to explore new environmental friendly cooling and lubrication techniques. One of these alternatives is machining with minimum quantity lubrication. It is a mixture of impinging of least amount of rice bran oil-based molybdenum disulphide and carbon black hybrid nano cutting fluid along with highly compressed air through a small nozzle results in reducing the heat produced during metal cutting. The effects of rice bran oil-based molybdenum disulphide and carbon black hybrid nano cutting fluid in minimum quantity lubrication (nMQL) on cutting performances in respect of chip formation, cutting temperature, surface roughness, and tool wear have been studied using coated carbide insert (SNMG) for medium carbon hardened steels (30 HRC, 35 HRC, 40 HRC). The same experiments have been carried out under dry condition in order to compare the results with those obtained under nMQL conditions. The result indicated that the machining with nMQL performed much better than dry machining mainly due to substantial reduction in cutting temperature enabling favorable chip-tool interaction and substantial reduction in surface roughness and tool wear. With the help of the experimental results, model of cutting temperature and surface roughness have been developed using an ANN model to understand the basic phenomenon in hard turning. Finally, the models demonstrated good agreement with experimental results to make it an acceptable model.