What are they? Metalworking Fluids...Basic Functions and Categories

I have to be honest, when I meet people who have no connection to metalworking and manufacturing, they tend to get a glazed look in their eyes when I tell them about what I do. So, for the uninitiated or the people out there who have a burning desire to learn something new I offer the following...

Basic Functions of Metalworking Lubricants:

Metalworking fluids or coolants play a critical role in most machining processes. The main functions of a metalworking fluid are:

COOLING: To reduce and remove heat build-up in the cutting zone and in the workpiece.

 LUBRICATE: and thereby reduce friction between the tool and the chips being removed.

CHIP REMOVAL: Flush chips away from cutting zone, carrying them back to the sump.

 PROTECT AGAINST CORROSION: of machine work piece and tools.

Classifications of Metalworking Lubricants

 Neat or Straight Oils: Neat oils are made up primarily of naphthenic or paraffinic base oils with extreme pressure additives such as chlorine, sulfur and fats. Neat oils will not emulsify with water nor do they contain any water.  

Soluble Oils:  Greater than 30% mineral oil and no water in concentrate. Dilution appears milky and not translucent.

Semi-Synthetics:  Less than 30% mineral oil content in concentrate and the concentrate contains water. Dilution appears translucent.

Synthetics: Zero mineral oil content. Dilution looks transparent and is a true solution with no droplet formation like semi-synthetics and soluble oils.