Technical Tip of the Week: When should I use a Lubricant or Coolant?

This is a common question from CNC router operators and getting it right will often make significant improvements to the efficiency and quality of your routing operations.

A coolant is used to prevent a router bit from becoming too hot during the cutting process. If a bit becomes too hot it will fail prematurely. It can also start to melt the workpiece which will very quickly prevent the tool from cutting and usually result in a broken bit.

A lubricant, as the name implies, is used to assist the cutting process by reducing the friction between cutter and the workpiece. Some materials, in particular aluminum will often start to weld the chips to the cutter if a lubricant is not used.

Not all coolants are lubricants, even though most lubricants also provide a degree of cooling. Compressed air, for example, works only as a cooling option, something you will want to do to control high temperatures during machining, and aid in chip evacuation. Compressed and cooled air can be efficiently applied to the cutter using a cold air gun and can often improve cut quality when machining plastics, especially those which are prone to melting.

The most common materials to require lubricant for successful cutting are non ferrous metals such as aluminum, brass and copper. Friction from cutting generates extreme heat which causes chips to become welded back onto the cutter and workpiece and quickly leads to broken tools and wasted material. Usually this is easily avoided by applying just a small amount of lubricant. A fine mist is all that’s required and this is best applied using an automated system such as the AXYZ Unist Mister. For anyone who is regularly processing aluminum this accessory is absolutely essential for long tool life, better cut quality and higher cutting speeds.

There are some router bits available today which claim to not require lubricant when cutting aluminum. They do this by having a special coating which reduces friction and therefore heat and can work well for some materials although they are more expensive and may not last as long as a regular router bit used with lubricant. If your manufacturing process requires no fluid or grease on the cut parts then these tools are highly recommended.

It’s essential that you understand whether you need a lubricant or coolant, and to use both of these products regularly and properly. Not only will they improve the overall performance of your machine, but they can help increase profits and production capabilities.

For information on the specific lubricants and coolants that are available for your CNC Router machine, contact your local AXYZ Service office.