Tribological evaluation of contact-charged electrostatic spray lubrication as a new near-dry machining technique

To minimize lubricant usage and friction at the chip-tool interface, a new near-dry machining technique called “contact-charged electrostatic spray lubrication” (CCESL) is proposed. In this study, the chargeability, penetrability, and wettability of charged lubricant droplets under CCESL conditions were investigated. The atomization and tribological properties of CCESL were compared with those of conventional minimal quantity lubrication (MQL) techniques under various testing-conditions. The experimental results suggest that CCESL improves tribological performance considerably and reduces lubricant consumption compared with conventional MQL. In addition, XPS analysis was used to investigate worn surfaces. The enhanced tribological performance of the new technique is attributed to the formation of a lubricating layer comprising an adsorption film and an oxide layer, which improves the surface quality.