Although commonly called a mist system, machining with minimum quantity lubrication has been shown to produce fewer emissions than flood cooling. It is, in fact, a low-emission process. Unfortunately, when starting with MQL, many shops think that more is better so they blast as much air as possible through the MQL nozzles and literally create a fog or mist of lubricant in the air. This is not MQL! A properly adjusted MQL system uses just enough air velocity to drive the lubricant to the tool, not enough to drive it around the block!
MQL has fewer emissions and is safer than standard flood coolant. Numerous studies measured the exposure of machine operators working around and inside of the machine as well as the more static levels just at the machine’s control panel. In the main study, which was conducted by the German government, the baseline was done using flood coolants. MQL was found to never have higher levels for aerosols, and the concentrations in more than 95% of the areas were less than half of the flood coolant baseline values.