Experimental investigation on the performance of composite electrostatic spraying milling using different inner/outer fluid combinations

Electrostatic spraying (ES) can improve the machining and environmental effects of minimum quantity lubrication (MQL). Compared with ES, composite electrostatic spraying (CES) presents better results because of excellent charging and cooling/lubrication performances. This article investigated the performance of CES milling using different inner/outer fluid combinations in terms of milling force, tool wear and oil mist concentration. Four inner/outer fluid combinations were employed in the study, namely, water/LB2000, multiwalled carbon nanotubes (MWCNTs)-water nanofluid/LB2000, water/MWCNTs-LB2000 nanofluid and MWCNTs-water nanofluid/MWCNTs-LB2000 nanofluid. For the analysis of the performance of CES milling, the charging property and atomization stability of CES and the electrowetting performance of composite droplet were measured. The results show that MWCNTs-water nanofluid/LB2000 was the optimal inner/outer fluid combination for CES milling from the view point of machining and environmental performances because of superior charging property, atomization stability and friction-reducing effect of nanoparticles.