Application of MQL with cooled air and wheel cleaning jet for greener grinding process

Metalworking fluids (MWF) or flooded process based on mineral oil are widely used in industry, which is unsustainable and causes damage to employees and the environment, in addition to making up a significant part of the machining cost. On the other hand, abrasive machining methods, such as grinding, are increasingly used for their excellent finish and geometric precision but use large quantities of metalworking fluids. This work evaluates the alternative methods Minimum Lubricant Quantity (MQL), MQL + Cooled Air (CA), MQL + Wheel Cleaning Jet (WCJ), and MQL + Cooled WCJ in the grinding of AISI 4340 steel compared to the application of flooded process. Surface roughness, roundness error, G ratio, grinding power, specific energy, microhardness, cost per piece, and carbon emission tests were applied. From the results, MQL reduced the cost of grinding around 90% and carbon emission by 67% compared to grinding with flooded process. The MQL + CWCJ produced the best results of surface quality compared to other alternative techniques, significantly approaching the results of the flooded process.