Effective lubrication and cooling are very critical to control friction and heat generation in metal-cutting processes. Conventionally, cutting fluids in flood form are employed during the processes; however, their usage is frequently seen to raise major environmental, economic, and employees’ health concerns. All these factors have urged researchers to search for alternatives to minimize or even eliminate cutting fluid usage. To serve that purpose, a new near-dry machining technique called “electrostatic minimum quantity lubrication” (EMQL) has been innovated and developed. EMQL is a technique using the synergetic effects between electrostatic spraying (ES) and minimum quantity lubrication (MQL), wherein a very small amount of lubricant, negatively charged by the electrostatically contact charged method, is directed into the machining area in the form of a fine, uniform, and highly penetrable and wettable oil mist. The focus of this study is to evaluate the performance of EMQL in end milling of AISI-304 stainless steel in terms of tool wear, cutting force, tool life, and surface roughness. The influence of EMQL process parameters such as charging voltage, air pressure, lubricant flow rate, and cutting speed is determined based on an experimental study. A comparison with the results obtained in completely dry, wet, and MQL machining is also provided. The experimental results show the effectiveness of EMQL as a viable alternative to conventional wet and MQL machining through the reduction in the friction at the tool–chip interface. It is found that the charging voltage is an important factor influencing the effective application of EMQL oil mist. EMQL with −5 kV voltage is recommended because it provides not only lower tool wear and cutting force but also higher tool life and better surface finish. In addition, it is found that there are the optimum lubricant flow rate and air pressure in end milling of AISI-304 stainless steel with EMQL. The proper selection of the above parameters can lead to a low-cost and eco-friendly machining.

•A contact-charged electrostatic spray lubrication technique is proposed.•The technique improves tribological performance and reduces lubricant consumption.•Enhanced performance is attributed to the formation of an abundant lubricating layer.•Guide the practical application of the new technique in machining.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.

•A nanosized lubricant complex of β-cyclodextrin (β-CD) and dialkyl pentasulfide (RC2540) was proposed as filler to phenolic resin-bonded grinding wheels.•The complex-filled grinding wheel considerably improves the tribological and grinding performance.•An anti-friction and anti-wear self-lubricating layer comprising sulfide and carbon-deposited films was formed during the grinding process.•Guide the formulation design and practical applications of novel grinding wheel.To minimize friction at the grinding wheel–workpiece interface, a nanosized lubricant complex of β-cyclodextrin (β-CD) and dialkyl pentasulfide (RC2540) was proposed as filler to phenolic resin-bonded grinding wheels. Complex-filled grinding wheels with different filling content (5, 10, 15, and 20 wt%) were prepared by the cold compression method and the tribological properties of the wheel specimens were investigated under different speed and load conditions. The grinding performance of the complex-filled grinding wheels was compared with that of an ordinary grinding wheel under different liquid coolant conditions (water and emulsified liquid). The experimental results suggest that the complex-filled grinding wheel considerably improves the tribological and grinding performance compared with those of the ordinary grinding wheel. A complex-filled wheel with 10 wt% complex is recommended because it provides not only higher grinding ratio and lower grinding force but also better surface finish. In addition, XPS analysis was used to investigate the workpiece surface. RC2540 is found to be released as the complex decomposes. The enhanced tribological and grinding performances of the wheel are attributed to the formation of an anti-friction and anti-wear self-lubricating layer comprising sulfide and carbon-deposited films, which improve the surface quality.