Effects of Machining and Oil Mist Parameters on Electrostatic Minimum Quantity Lubrication–EMQL Turning Process

A cost-effective and eco-friendly alternative to conventional flood cooling-lubrication and minimum quantity lubrication (MQL) is electrostatic minimum quantity lubrication (EMQL). EMQL, which is a novel green machining technology that utilizes the synergetic effects between electrostatic spraying (ES) and MQL, has been successfully shown a potential in milling process. However, the effective application of EMQL is not only connected with machining parameters, such as cutting speed and feed rate, but also related to oil mist parameters including charging voltage, lubricant flow rate, air pressure, and nozzle position and distance. This paper investigated the effect of the above parameters on the cutting performance of EMQL turning stainless steels in comparison with completely dry and conventional wet and MQL cutting. The results suggested that cutting speed and voltage were important factors affecting the effectiveness of EMQL, and found that there were the optimum air pressure and nozzle position and distance when EMQL turning AISI 304 stainless steel. Properly selecting these parameters, a viable alternative to wet and MQL cutting could be achieved by promoting lubricants into cutting interface to reduce friction and adhesion of work-piece materials on the interface.