CNC Router Aluminum Cutting

Author Bob Warfield posted a great article on ways to improve aluminum cutting with a CNC Router. We have summarized it below but you can read the full article here:

When using a CNC Router, people usually think about primarily cutting wood and plastics. However it is also a great tool for cutting aluminum. There are a couple things to remember about aluminum in terms of how they differ from woods and plastics. First of all they have much smaller sweet spots for optimal feeds and speeds and if you leave that spot, cutters can start to break and you sacrifice surface finish quality. Below is a diagram showing the various sweet spots depending on what you want to accomplish. Secondly, aluminum has a stickiness factor meaning the material wants to stick to the tool. Despite these challenges, you can cut aluminum very successfully with almost any router, here are 6 tips for CNC Router aluminum cutting success.

sweet spots feeds and speeds

  1. Don’t be in a hurry

The price you pay for success is slowing things down, this doesn’t mean literally slowing down your feeds and speeds, but your overall material removal.

  1. Use a feed rate calculator

All CNC’ers can benefit from a feed rate calculator, but when you’re near the edge of the performance envelope, you want to be particularly careful. Click the following link to be taken to our very own feed rate calculator

  1. Be paranoid about clearing chips

Recutting chips can cause a lot of router bit breakage. Be paranoid about clearing the chips and don’t always count on a nearby vacuum dust collection system unless you have personally verified it sucks the chips out even the deepest cuts.

  1. Watch cut depths and slotting

The deeper you cut and the closer to a slot the cutter travels in, the harder it is to clear the chips out of the bottom of the hole. Make more passes to cut down to required depth and to open up the shallower depths for better access.

  1. Lubricate with mist

The next issue is providing lubrication to cut down the tendency for the chips to stick to the cutting edges.

  1. Use fewer flutes and increase cut width

Normally you should be using 3 or fewer flutes with aluminum, don’t ever try a four or more flute bit. The reason is that aluminum produces especially large chips. The fewer the flutes, the more space between the cutting edges, and the more room for the big chips to escape and be blown away.  With too many flutes, the chips back in too tightly, jam up the flutes, and pretty soon you have a broken bit.



In conclusion, machining aluminum with a CNC Router is absolutely doable with almost any router. It’s just a matter of matching your machine’s capabilities to the “sweet spot” feeds and speeds requirements of the material through wise selection of tooling and cutting parameters. Add to that the need for lubrication and being paranoid about chips piling up and you’re ready to tackle an aluminum project. MultiCam offers a wide variety of CNC Routers which can be found here, and router bits which can be found at the


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