Abstract: Minimum quantity lubrication(MQL) atomized droplets are easy to fly and disperse, which is the bottleneck problem of MQL grinding. This not only threatens the environment and workers' health, but also reduces the effective utilization rate of lubricant.A new grinding process of electrostatic minimum quantity lubrication(EMQL) is innovatively proposed, which can accurately control the average particle size and particle size distribution of atomized droplets under the coupling effect of airflow field and electrostatic field. To explore the effect of voltage on droplet migration activity, the atomization and charging characteristics of lubricant under MQL and EMQL were compared and analyzed. Compared with MQL, the average droplet size and the R.S. value of droplet size distribution span is decreased by 29.56% and 47.85% respectively when the voltage is 40 kV. And the droplet migration activity is also improved. The charge mass ratio of the droplet is 0.302 mC/kg at 40 kV. To reveal the EMQL grinding mechanism of titanium alloy Ti-6Al-4V, grinding experiments of different lubrication conditions(dry, flood, MQL and EMQL) were carried out. The results showed that the minimum tangential grinding force and normal grinding force(28.53 N and 77.18 N) were obtained under EMQL condition. Compared with dry, flood and MQL conditions, the friction coefficient is reduced by 29.39%, 9.31% and 13.95% respectively, and the specific grinding energy was reduced by 51.34%, 18.40% and 30.11% respectively. The surface morphology of the workpiece is found no adhesion recast layer observed by laser confocal microscope under EMQL condition. The optimal workpiece surface is obtained at 35 k V, and the surface roughness S_a is 0.84 μm. The number and size of adhesion points were significantly reduced.

Key words: grinding, MQL, titanium alloy, electrostatic atomization, migration activity