Aluminum, despite being much softer than steel, presents its own issues when it comes to milling. Milled aluminum is a common material used to construct parts that need to be light but strong. In order to properly machine this metal, the right end mills for aluminum have to be used. Trying to mill components using the same tools you would use for harder metals like steel would be a mistake that could ruin both your tools and your workpiece.

Chip Size
The largest hurdle to overcome when machining aluminum is chip size. Steel is strong and when you cut into it at high speeds, shavings are removed almost like you’re working with wood. Aluminum forms much finer chips that are almost a fine powder. These chips, if not properly evacuated from the cutting area, can build up around the base of the cutter and compact to the point where it can seriously damage your cutter.

Flute Count
When choosing end mills for aluminum, you are going to want to limit the number of flutes on the cutter. Fewer flutes means more space between flutes and more distance between cuts. This gives the fine chips from each cut more room to be successfully evacuated from the toolpath. Most aluminum specific milling cutters have three flutes, though two and four fluted options are occasionally used.

Flute Angle
So the number of flutes is crucial, but the angle of those flutes is also important. Flute angle influences the ability for the chips to be accelerated away from the cutting path. The higher the flute angle, the faster the chip evacuation. Most end mills use a lower helix angle around 30 degrees, but end mills for aluminum should have helix angles ranging from 35 to 45 degrees.

Coating
Finally you are going to want to take a look at the coating being used on your end mills. These coatings not only help to protect the tool from heat and strain, but coatings like the gold colored zirconium nitride help to lower the friction coefficient of your end mill’s surface. This means that the coating makes it harder for chips to stick to your cutter and the surface will help those chips slide away smoothly. This material is actually a fine layer of hard ceramic that is deposited onto the surface of the end mill as a vapor, creating a coating that is remarkably strong and thin.

If you want to see some fantastic end mills for aluminum, you need to check out Online Carbide. They are an American manufacturer dedicated to producing high quality end mills precision milled from solid carbide stock. Their Aluminum end mills feature a three flute design with a 37 degree helix angle to promote efficient chip evacuation. If you have any questions about their tools, feel free to reach out to a member of the Online Carbide team by sending an email to [email protected].