Capillary penetration mechanism and oil mist concentration of Al2O3 nanoparticle fluids in electrostatic minimum quantity lubrication (EMQL) milling.

A green manufacturing technology named "electrostatic minimum quantity lubrication (EMQL)" with water-based Al₂O₃ nanoparticle fluids as cutting fluids was developed in order to improve the cutting property and minimize oil mist concentration during the machining process. The capillary penetration mechanism, oil mist concentration, and heat transfer property of Al₂O₃ fluid EMQL were investigated. The cutting performance of Al₂O₃ fluid EMQL and traditional minimum quantity lubrication (MQL) was compared. The results showed that EMQL could improve the penetrability and heat transfer capacity of the lubricant effectively. Compared with Al₂O₃ fluid MQL and oil-based MQL, Al₂O₃ fluid EMQL reduced oil mist concentration and cutting temperature remarkably and showed similar cutting performances compared with the oil-based MQL. The excellent performance of this water-based Al₂O₃ fluid EMQL technology was mainly due to that EMQL could promote a further penetration of the charged Al₂O₃ nanofluid droplets into the cutting region, which thus reduced the friction force, and the tool durability was maintained obviously and finally presented better machining performance. [ABSTRACT FROM AUTHOR]