Laboratory Evaluation of Metalworking Fluids
This chapter presents an overview of the many evaluation methods applied to metalworking fluids (MWFs). Manufacturers will spend hundreds of thousands of dollars on the machines, tens of thousands of dollars on the skilled operator, hundreds or thousands of dollars on the cutting tool or grinding wheel, and only pennies per mix gallon on the MWF. A laboratory test method must be meaningful. It must simulate the most important conditions of the metalworking operation. If the MWF is designed to be further diluted with water prior to use, then this mixture needs to be evaluated for stability. Dilution stability will depend upon both the quality of the MWF concentrate and the quality of the water used for dilution. Air forced into MWFs can be held at the fluid surface as bubbles of foam, or it can create two other phenomena: air entrainment or misting.