Aluminum is a lightweight, durable, and corrosion-resistant metal that is electrically conductive. It comes in a vast number of different alloys, each with different physical and thermal properties. Some of these alloys are easily cast, wrought, machined, or extruded. Other alloys are extremely strong, ductile, or resistant to stress cracking. The most commonly used, general-purpose alloy is 6061 aluminum, and it’s our favorite alloy for milling because it’s a great blend of strength and machinability. It’s strong enough to be used for many applications but soft enough to mill.
Aluminum is used for everything from engine parts to MacBooks to jewelry, soda cans, airplanes, and so much more. The milling machine bed, spoilboard, and Z-carriage are all made of aluminum. It's popular because it’s a great blend of price, strength, and machinability, and it can be anodized to give a premium surface finish.
We sell precut pieces of 6061 aluminum in our store! They’re the perfect size for many milling machine projects, and they fit nicely on the machining bed. You can also get aluminum from metal suppliers, scrap yards, and even soda cans. Just make sure you know what alloy it is, lest you risk encountering one that's difficult to mill.
Use the biggest tool you possibly can to allow for the fastest material removal and least chance of tool breakage. The easiest tools to use are ¼”, 1/8", and 1/16" flat or ball end mills. Aluminum is one of the less forgiving materials, and it’s easy to break small tools with too high of a feed rate or inadequate fixturing. The ¼”, 1/8", and 1/16" tools are very strong, and they can cut away a lot of material at once. That being said, any tool can be used to mill aluminum as long as the settings are correct.
Make sure to keep aluminum dust and chips out of your eyes or lungs. We recommend vacuuming after each milling job and in the middle of jobs longer than 30 minutes.