To overcome health, safety and oily work environment issues with metalworking fluids, MAG advanced the concept of Cryogenic Machining a decade ago.  Today they have more than 300 machines in the field utilizing the technology, and have developed significant expertise for dry and near-dry machining.  Though they claim many advantages of MQL technology, the fact is it does not do as well at extracting heat.  Metalworking Fluids always score better in that.  Article on Aerospace Manufacturing and Design.