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Need For Speed (And Feed): Understanding The Jargon Of Milling Tools

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 Machine milling jobs are much more complicated than running material through a machine. It involves many factors and quite a bit of math. So it shouldn't be much of a surprise to know they also use complicated jargon. Speeds, feeds, and depth of cut are three terms you should understand if you are supervising machinists.

Speed. Speed is usually the first property that machinists consider before cutting. There are two types of speeds on a bit.

  • Spindle speed is how fast the spindle rotates. The spindle is the piece of the machine that holds the bit. This speed depends upon the amount of power in the motor that rotates the machine. Rotating the spindle too quickly could also blow the motor depending on the age of the machine.
  • Cutting speed refers to how fast the cutting surface of the bit moves across the material being cut. This speed might also be called the surface speed. This speed is dependent on a variety of factors. The main factor concerns the material the cutter and item being cut are made of. Manuals for end mills typically come with the optimal cutting speed for each material. However, other variables, such as the age of the end mill and vibrations in the machine, can affect this speed.

Feed. Feed is simply the rate at which material is being fed to the machine. This can be increased or decreased depending on the depth of cut and the material being cut. For example, material like wood should have a higher feed rate so the friction from the machine doesn't cause it to burn. It also depends on factors such as how many teeth the end mill has. So, feed rate is much more variable than cutting speed.

Depth of Cut. This term is self-explanatory. Depth of cut is how deep the bit is driven into the material. This is another variable factor because it depends on the job that is being completed.

So how do machinists come up with all of these numbers? You might not know it, but determining cutting speed and feed rate involve complex mathematical formulas that take all of the variables into account. Having the correct speeds and feeds will ensure that the material being worked with isn't damaged. It also increases the life of the end mills. Miniature end mills are quite small, and therefore easier to break than larger tools. It is vital to pay attention to the manual of the bits and to have skilled, trained machinists who can adjust their speeds and feeds according to the project.

For more information, visit a site like to learn more about miniature end mills.