Aluminum is becoming increasingly more popular among machinists due to its unique properties. Its “gumminess” makes it a pleasure to machine, especially with heavy cuts and high feed rates. Moreover, there is a point, right around the 15.000 RPM mark, where chatter seems to disappear completely, allowing the machine to attack the material and find purchase without a problem or fear of bouncing.
However, these speeds can only be reached when using robust carbide tools that can spin without wobbling or losing their sharpness, especially when going full rapid. There are three elements solid carbide end mill manufacturers recommend keeping an eye on when working with aluminum.
You need a coated tool to make sure it retains its hardness, especially when running at high speeds. Titanium aluminum nitride coatings are incredibly rigid and work extremely well at high speeds. When pushed to high temperatures, the composite forms a thin layer of aluminum oxide that reforms continuously, protecting the bit from wear, even when dry milling. These properties would make TiAlN mills great candidates for high-speed machining. However, using aluminum on aluminum can cause a few problems, namely chip buildup or welding on the flutes, causing problems on the surface finish. The problem can be prevented by keeping the coolant flow in check.
Zirconium Nitride composite coatings work best for cutting aluminum at higher speeds. By decreasing friction and increasing lubricity, ZrN provides better chip evacuation which is vital when working with softer or gummier aluminum. ZrN prevents tool clogging and produces better chip curls that nest nicely away from the workpiece.
Flute count is extremely important when milling aluminum as chip curls can easily clog tight flutes. However, it is hard to hit aluminum fast enough to reach the desired 500-800 strikes per minute with a 2-flute mill. That’s why 3-flute tools are the way to go for aluminum. They provide enough space for efficient chip evacuation and guarantee enough strikes per second to prevent chatter.
Geometry is also extremely important when choosing the right tool for aluminum work. You need a tool with a steep helix angle that allows you to easily calculate optimal harmonic conditions when running at high speeds. 37° degrees will keep pull forces from relaxing preload forces on your spindle bearing, especially if it is spring-loaded. This is important if you want to stay true to your testing calculations.
When pushing your shop towards high-speed or high-performance machining, these seemingly small factors can make the difference between running an efficient machining process and a tool demolition operation.
If you are looking for tools specifically designed for maximum efficiency, you need tools from the best solid carbide end mill manufacturers. Online Carbide offers reliable ZrN coated carbide tools at the best prices. Visit their website or call 630.238.1424 to speak to a professional sales representative that will help you find the right tools for your needs.