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Aluminum

Aluminum is a strong and lightweight metal used in all sort of modern applications from our bikes to our laptops. CNCing aluminum is a great option to get useful parts, especially for mechanical systems and tools.

Aluminum comes in a variety of different alloys. We will primarily be talking about 6060 aluminum, which is the most commonly used alloy.

General feeds and speeds using a 1/8″ single flute flat aluminum cutting end mill. Please note that these settings are for basic cutting such as with CAMLab or Kiri:Moto and not for adaptive toolpathing operations which have other settings.

Material Feed Rate (mm/ min) Plunge Rate (mm/ min) Step Over Step Down (mm) Spindle Speed (RPM)
6061Aluminum12001000.20.413,000
  • Aluminum is near the upper limit of hardness that you want to be milling with a desktop hobby CNC machine. Setting up your machine to be as rigid as possible (milling near the supported areas of your rails, using proper clamping, reducing stick-out of your end mill) can make a difference.
  • The most common cause of end mill breakage is when chips build up and melt onto your bit. Ensuring that you have the proper chipload and chip ejection is important to draw heat out of the cut. Some users may choose to use coolant or compressed air to cool their cuts. Make sure to keep chips out of the cut at all times.
  • Most routers run at relatively high RPMs (10,000 to 30,000RPM) for cutting metals. Because of this, it is best to use single flute bits like our 1/8″ flat end mill for aluminum to ensure that you can get optimally sized chips. Also, reducing your RPM can help.
  • Some coatings, especially ones with coatings that contain aluminum (AlTiN, TiAlN), should be avoided as aluminum chips can have an affinity to the coating.
  • Using an advanced CNC CAM program such as Fusion 360 that allows for adaptive toolpathing can speed up your cutting and give you better results, but if you’re planning on cutting a lot of aluminum, it may be worth learning.