Aluminum has a reputation for being a soft and versatile metal. It surprises most people to learn just how difficult it is to machine solid aluminum. When cut by an end mill, aluminum is so soft that it produces miniscule chips that are nearly a fine aluminum powder. These fine chips are so lightweight that they can be difficult to evacuate from the surface of the cutter. The best end mills for aluminum employ a number of unique features in order to make the process of machining aluminum easier.
Because the chips produced by aluminum are so small, they can easily get stuck around the base of a tool’s flutes. The heat and pressure created by the machining process can cause this powder to solidify at the base of your tool, potentially damaging the end mill and your workpiece. Tools with fewer flutes provide more room for chips to be evacuated. Three flute end mills are one of the most common options for machining aluminum, which is fewer flutes than what is typically recommended for machining other metals.
Not only does machining aluminum require fewer flutes, it also requires a higher helix angle. The helix angle is the angle formed between a tangent along the cutting edge of a flute relative to the central axis of the end mill. Many end mills feature flute angles around the 30 degree mark, but the best end mills for aluminum will have higher helix angles from 35 to 45 degrees. This steeper angle helps to provide more vertical force to the chips, helping to send them up and away from the base of the cutter.
The two main materials used in end mills for machining aluminum are steel and carbide. Both of these materials are strong enough to cut through aluminum without issue, but carbide tends to be the superior choice. A carbide cutting tool’s edge retention and ability to withstand high temperatures is superior to that of steel tools. This is because of the fact that carbide end mill tool stock is a combination of powdered ceramic carbide and cobalt metal. The ceramic content is more dense and rigid than steel, giving these tools incredible cutting power.
Finally you need to consider coatings. A simple polished finish might suffice, but there are several coatings that can be applied to these tools in order to make them more effective. Zirconium nitride is a common gold colored coating that is extremely hard and helps to lower the friction coefficient of the end mill. Smoother tools means better chip evacuation, which is why most tools will feature some form of coating.
If you are trying to find the best end mills for aluminum for your shop, you need to check out Online Carbide. They offer a wide range of solid carbide drill bits and end mills, including end mills for aluminum. If you have any questions able any of their products, feel free to reach out to a member of their team by sending an email to firstname.lastname@example.org