Aluminum is one of the most
useful production materials we use. It is extremely strong even though it is relatively lightweight for a metal. Aluminum is also one of the softer metals, so it can be milling into custom components quickly and easily. Even though aluminum seems much easier to mill on paper, it does have a few quirks that can make it challenging for machinists unless they are using special end mills for aluminum. These end mills differ from those used on other metals for a few important reasons.
When you machine steel and other hard materials, you want to have a cutter with several flutes. When you cut into steel, the rigid metal breaks into small chips, which are easily flung away from the cutter. Adding more flutes helps to keep these pieces small and lower the strain on each cutting edge, leading to superior metal removal rates.
Unlike ferrous materials, aluminum alloys are soft and easy to work with. This seems like a positive trait until you think about the process of removing aluminum from a piece. Instead of forming clean breaks and making small chips, aluminum chips flex without breaking, forming long ribbon-like chips of aluminum. These chips can be difficult to evacuate from the base of your cutting tool.
Creating end mills for aluminum is all about making the evacuation of these chips an easier process. Instead of favoring more flutes like a steel cutting tool, aluminum cutters have to be made with fewer flutes, typically 2 or 3 flute tools are used. Machining aluminum is all about high speeds, and the wide flute spacing makes chip evacuation much easier.
If aluminum is not properly evacuated from the base of the cutter, it can build up and cause jams that could damage your tools and your workpiece. The build-up of aluminum in the teeth of your cutting tools can also heat it to the point where it forms a solid mass, potentially causing more damage.
To prevent aluminum from sticking to and building upon the surface of cutting tools, many of these end mills are coated with materials like ZrN. ZrN is a golden-colored coating that has a low coefficient of friction, making it harder for aluminum chips to stick. Many of these tools will also have a higher helix angle than average, which puts more upward force on the chips.
If you need some end mills for aluminum, then Online Carbide is a great place to get them. At www.onlinecarbide.com you will find a great selection of solid carbide milling tools including end mills and drill bits. Their aluminum tools are 3 fluted end mills with a 37-degree helix angle and a ZrN coating. They are perfect for machining at high speeds and feeds and are always available at manufacturer-direct prices. If you have any questions about their tools, feel free to reach out to a member of their team by sending an email to [email protected]