Editing Cutting fluid (section)

{{Short description|Coolants and lubricants used in metalworking}}
[[Image:Makino-S33-MachiningCenter-example.jpg|thumb|Thin-wall milling of [[aluminum]] using a water-based cutting fluid on the [[milling cutter]].]]

'''Cutting fluid''' is a type of [[coolant]] and [[lubrication|lubricant]] [[designed]] specifically for [[metalworking]] processes, such as [[machining]] and [[Stamping (metalworking)|stamping]]. There are various kinds of cutting fluids, which include oils, oil-water [[emulsion]]s, pastes, gels, aerosols (mists), and air or other gases. Cutting fluids are made from petroleum distillates, [[animal fat]]s, [[plant oil]]s, water and air, or other raw ingredients. Depending on context and on which type of cutting fluid is being considered, it may be referred to as '''cutting fluid''', '''cutting oil''', '''cutting compound''', '''coolant''', or '''lubricant'''.

Most metalworking and machining processes can benefit from the use of cutting fluid, depending on workpiece material. Common exceptions to this are [[cast iron]] and [[brass]], which may be machined dry (though this is not true of all brasses, and any machining of brass will likely benefit from the presence of a cutting fluid).<ref name="Camm1949">{{cite book|author=Frederick James Camm|title=Newnes Engineer's Reference Book|url=https://books.google.com/books?id=iXxGAAAAMAAJ|year=1949|publisher=George Newnes|page=594}}</ref>{{Contradictory inline|date=March 2025}}

The properties that are sought after in a good cutting fluid are the ability to:
* Keep the workpiece at a stable temperature (critical when working to close [[Tolerance (engineering)|tolerance]]s). Very warm is acceptable, but extremely hot or alternating hot-and-cold are avoided.
* Maximize the life of the cutting tip by lubricating the working edge and reducing [[Built up edge|tip welding]].
* Ensure safety for the people handling it (toxicity, bacteria, fungi) and for the environment upon disposal.
* Prevent rust on machine parts and cutters.