A customer recently asked about what style of end mill to use for his aluminum application. Here are some general guidelines:
It is a trade-off between chip-evacuation and finish. A lot of times with aluminum the long stringy chips can clog up the flutes. This often leads to re-cutting the chip, which is the main cause of tool failure with end mills. So the chip-evacuation is important, but depending on the grade of aluminum and the cut, you could use a 4 flute. Generally, the less flutes = better chip-evacuation AND more flute = better finish/more work per rotation of tool. The aluminum cutting tools you have on this order have a higher helix angle (45 degree instead of 30 degree) which creates a better finish through more of a shearing action as the end mill cuts. The aluminum style also has deeper spaces between the flutes for better chip-evacuation. The core-diameter of the tool does not need to be as large when cutting aluminum, so this deeper flute design works well. These are high performance tools designed for maximum material removal rates and should be run at the speeds and feeds for the high performance tools on our website.