Carbide
Carbide stays sharper longer. While it might be more brittle than other end mills, we’re talking aluminum here, so carbide is great. The biggest downside to this type of end mill for your CNC is that they can get pricey. Or at least more expensive than high-speed steel. As long as you have your speeds and feeds dialed in, carbide end mills will not only cut through aluminum like butter, they will also last quite a while. Get your hands on some carbide end mills here.
Coatings
Aluminum is soft when compared to other metals. Which means chips can clog up the flutes of your CNC tooling, especially with deep or plunging cuts. Coatings for end mills can help alleviate the challenges that sticky aluminum can create. Titanium aluminum nitride (AlTiN or TiAlN) coatings are slippery enough to help keep chips moving, especially if you aren’t using coolant. This coating is often used on carbide tooling. If you’re using high-speed steel (HSS) tooling, look for coatings like titanium carbo-nitride (TiCN). That way you get the lubricity needed for aluminum, but you can spend a little less cash than on carbide.
Geometry
So much of CNC machining is about math, and choosing an end mill is no different. While the number of flutes is an important consideration, flute geometry should also be considered. High-helix flutes help dramatically with CNC chip evacuation, and they also help with the cutting process. High-helix geometries have more consistent contact with your workpiece… meaning, the cutter is cutting with fewer interruptions.
Interrupted cuts are hard on tool life and surface finish, so using high-helix geometries allows you to stay more consistent and move CNC machine chips out faster. Interrupted cuts wreak havoc on your parts. This video shows how interrupted cuts with a chipped end mill can affect your cutting strategies.
Post time: Jul-03-2019
