Metalworking fluid (MWF) is a term that refers to the spectrum of oils and other substances that are used to cool and/or lubricate metal pieces as they are ground, machined, or milled. MWFs decrease friction and head between work pieces and cutting tools, which assists in preventing smoking and burning.
MWFs also improve workpiece quality by continually taking chips, fines, and swarfs or small metal pieces from the tool at hand and the workpiece surface. There are four basic MWF classes: straight oils, soluble or emulsifiable oils, semi-synthetic fluids, and synthetic fluids. Each class may contain additives such as corrosion inhibitors and stabilizers.