State of the Art of Biodegradable Nanofluids Application in Machining Processes

For ecological and health issues of those involved in the manufacturing, usage, handling, and disposal of cutting fluids, research has been developed for scientific and technological advances in biodegradable cutting fluids, application methods, and solid nanolubricants. Using a minimum quantity of lubricant (MQL) in machining processes proved to be a viable alternative to replacing low-pressure jet machining. Nanoparticles from 5 to 100 nm in size are usually dispersed in vegetable-based cutting fluid; this combination improves the tribological properties of the nanofluid and the machinability of metal alloys like steel, titanium, nickel, and aluminum alloys, with reduced cutting forces, cutting temperature, tool wear and workpiece surface roughness. This work aims to present an updated summary of the lubrication and cooling action provided by using the MQL technique, biodegradable cutting fluids applied by MQL, the use of nanoparticles added to the cutting fluids, and the physical properties of nanoparticles, tribological characteristics, and the behavior of the nanofluids. The changes in machining force, cutting temperature, surface integrity, and wear of cutting tools with biodegradable nano-cutting fluids are also focused on. The use of nanoparticles in cutting fluids associated with MQL application has shown an increase in the lubricating and coolant properties of cutting fluids, which contribute to the reduction of machining force, cutting temperature, workpiece surface roughness, coefficient of friction, and wear of cutting tools. Thus, the results of this summary can provide theoretical support and experimental guidance for exploring the lubricating and cooling properties and the mechanism present in film formation with nanofluids at the chip-too-workpiece interfaces. Knowledge of such phenomena helps to popularize an eco-friendly practice in metal-mechanic industries.