A Review on Nanofluids for Machining

Background: The research on use of nanofluids for machining applications has gained more attention for over the past two decades. However there is limited review/data, available on the basis of individual nanoparticles performance, when added as an additive to coolant (cutting fluids)/lubricant used for machining applications. Hence, this article meticulously attempts to come up with an individual nanoparticle wise review, on a wide range of past and present ongoing research and focuses on affirmative aspects of using nanoparticle added coolants/lubricants (nanofluids) used for metal machining. Method: Investigations by researchers all around the globe reveal that addition of nanoparticles to coolants/lubricants has shown better heat dissipation ability at the machining zone. In the present work an attempt is made by conducting a study of 102 research papers, to come up with a report on individual nanoparticle wise comprehensive review, on the effect of suspending 11 different nanoparticles in various coolants/lubricants used for machining applications. The article is structured in a cogent way, starting with a brief introduction to nanofluids, followed by an individual nanoparticle wise review. Each review section comprises of introduction to the individual nanoparticle, its distinct properties, its method of synthesis and unique advantage upon addition to coolant/lubricant used for various machining related applications. Results: Addition of nanometer sized particles in suitable proportions to servo cut oil, canola oil, deionized water, coconut oil, vegetable oil, colza oil and soyabean oil used as coolants for machining of different materials like aerospace alloys, steel(of different grades), nickel based alloys etc. have proved to enhance the machining performance. Out of the 11 different nanoparticles, Al2O3, Gr, MoS2, SiO2 and TiO2 find themselves suitable for maximum machining applications. Use of new coolant supply systems like MQL attempt to promote eco-friendly machining with reduced use of coolants and hence the costs associated with machining. Conclusion: The present review covers most of the important works done by researchers in the area of nanofluids. Effective applications of MQL techniques for machining, call for high thermal conductivity fluids. Hence, from the past two decades the concept of nanofluids has been a revolutionary and appealing area for the researchers. To summarize nanoparticles as additives to coolants/lubricants combined with Minimum Quantity Lubrication systems could be useful in performing the machining operations with reduction in cost and pollution.