Metalworking Fluids Glossary

Bacteria and Mold: Microscopic organisms that naturally occur in industrial fluids. If left to grow unchecked, they can cause odors, dermatitis and rust on parts.

Biocide and Fungicide: Chemical agents used to kill and consequently control microbial organisms (e.g., bacteria, fungi, yeast, and mold) in MWFs. These can be formulated into the concentrate or added to the sump.

Biological Testing: Testing for the presence of bacteria, yeast, and mold by the use of paper- like test strips or paddles coated with a media that allows the bacteria and mold to grow on them; then they are  measured.

Concentration Control: Metalworking fluids are mixtures of ingredients, each performing a definite function. Concentration control, which can be accomplished by a number of different methods, checks the overall concentration or the level of several of these components during use in the plant.

Defoamer: A chemical additive that physically alters the surface tension of a fluid to reduce or eliminate foaming. It can be formulated into the concentrate or added tank side.

Dilution or Concentration: The ratio or percent of water to concentrate in the machine sump

Fines and Swarf: Metal fines and grinding wheel particles generated during grinding or machining

"Neat" Oil: As it comes from the drum, not diluted. Refers to either "straight oil" not intended to be further diluted with water, or to "soluble oil," as it comes from the container, before mixing with water to form soluble oil and waterMWF mixtures.

pH: This is an expression that is used to indicate whether a substance is acidic, neutral, or alkaline. A pH measurement determines the degree of acidity or alkalinity of a metalworking fluid mix.

Rancidity: A term used to describe a system that has been overcome with bacteria, mold, and/or fungal growth, and has a strong and foul ("locker room") odor.

Refractometer: An optical instrument that measures the refractive index of a water soluble MWF and is used to determine concentration. Skimmer: A device for removing floating tramp oil from the surface of the MWF.

Tank Side Additive: Products used to control foam, bacterial, or fungal growth that are added to the working sump.

Titration: Chemical titration methods can be established to measure either overall concentration or certain components or groups of components in any fluid mix. These would include measuring the alkalinity, the anionic content, the nonionic level, or the sulfonates.

Tramp Oil: Oil that is present in a metalworking fluid mix and is not from the product or concentrate. The usual sources are machine tool lubrication systems and leaks.

Water Quality: A measurement of the levels of calcium, magnesium, and chloride that affect the performance of a metalworking fluid. Hard water would have high levels of these metals and would form residues. Soft water would have low levels and tend to foam.