In various manufacturing processes, metalworking fluids (MWFs) are applied to ensure workpiece quality, to reduce tool wear, and to improve process productivity. The specific chemical composition of an applied MWF should be strongly dependent on the scope of application. Even small changes of the MWF-composition can influence the performance of MWFs in manufacturing processes considerably. Besides defined variations of the composition, the MWF-chemistry furthermore changes over the service life of the fluid. This paper presents the current state of the art regarding the assumed working mechanisms of MWFs including the effects of desired and undesired changes of the MWF properties.
