Vegetable oil-based nanofluid minimum quantity lubrication turning: Academic review and perspectives

Metal cutting fluids have a huge negative impact on human health and environmental ecology, thus posing a serious threat to the sustainable development of the global manufacturing industry. Meanwhile, turning processing is an important part of metal material removal processing, and achieving sustainable lubrication is a major problem that needs to be solved urgently. Using vegetable oil to atomize and spray the tool/chip and tool/workpiece interface through the minimum quantity lubrication (MQL) supply system is a feasible way to achieve environmentally friendly turning. Moreover, the preparation of nanofluid by adding nano-reinforced phases to the degradable bio-lubricant can greatly improve the lubricating performance of the micro-droplets. However, conventional research have only focused on individual factors, such as cutting parameters, types of base oil and nanoparticles, and supply parameters. Thus, these studies are unable to provide effective guidance for the turning processing applications related to nanofluid minimum quantity lubrication (NMQL). In order to fill the gaps in the relevant literature, this paper examines the current advanced research on NMQL and explains the experimental phenomenon through the concept of lubrication mechanism. First, the advanced multi-energy field atomization technology and the influence mechanism of the physical and chemical properties of vegetable oil were reviewed. Subsequently, the influence laws governing nanofluid preparation as well as nanoparticle characteristics and concentration were summarized. Furthermore, textured tool and ultrasonic vibration-assisted nanofluid turning are proposed to increase the effective flow rate. Finally, the challenges and future trends of vegetable oil-based NMQL turning processing are proposed.