Metal Cutting Fluids – What best for a coolant?

We’ve covered the basics of metal cutting fluids as well as the most important things to consider for selecting a metal cutting fluid or lubricant for your business. Today we’ll be focusing in more closely on one type of fluid- coolants.

Coolants are used, as their name suggests, to assist in controlling the temperature in a variety of industrial processes. Often, during metal cutting and machining actions, the friction caused will result in a great deal of heat being created as a side effect. In order to avoid warping of metals and machinery, to which most machines and products are more susceptible when at high temperatures, coolants are applied.

Whilst metal cutting fluids in general have a wide variety of bases depending on their purpose, most coolants used in metal cutting and machining are water soluble solutions. This means that they contain both a base mineral oil which forms an emulsion and water. This variety of fluid is the most widely used in metal cutting broadly, but is particularly useful for the purposes of cooling. This is because they are both versatile and relatively inexpensive.

Water Soluble cutting fluids are used in cooling purposes particularly because they have excellent thermal conductivity, spreading heat more quickly that either purely oil based fluids, or synthetic cutting fluids. They combine the high boiling points of oils, with the versatility of the more manufactured fluids. The latent of coolants changing state from liquid to gas can often be taken advantage of as a means of advancing the cooling capacity of a liquid further, although many fluids are also designed to keep their state during cooling processes, so this is another factor to keep in mind.

Where suitable, gases and vapours can sometimes be used as coolants. Carbon Dioxide for example, is often used for cutting tools, but doesn’t have the same lubrication qualities, and is difficult to apply to all areas of machinery, whereas as fluids can reach areas of machinery during cutting that would otherwise struggle to be as accessible.