Machining Aluminum: How to Choose the Right End Mill?

Machining aluminum can be a tricky endeavor, but having the right tools makes the job much easier. Aluminum is one of the most widely used materials in machining, and having the right end mill can make a world of difference in your finished product. With the right end mill, you can maximize the quality and efficiency of your machining process.

But how do you choose the right end mill for aluminum? In this blog post, we’ll look at some things to keep in mind when choosing the right one for your aluminum machining project.

What to Keep in Mind When Choosing the Right End Mill for Aluminum

Carbide End Mill

When machining aluminum, a carbide end mill is a great choice. It stays sharper for longer and produces smoother cuts than other materials. It’s important to keep in mind that carbide is more brittle than other materials and should not be used for extremely tough materials. But since aluminum is light and easy to cut, carbide is great.

The downside to this type of end mill is that they can get a bit expensive. However, as long as you have your feeds and speeds dialed in, this type of end mill will cut through aluminum like butter and will last quite a while. Overall, a carbide end mill is an excellent choice when machining aluminum. It offers superior sharpness and longevity, resulting in smoother cuts. Just make sure to select the right type of flutes and the correct size of end mill for your specific application. We’ll go deeper into that later.

The Coating Of an End Mill

Coatings on the end mill can make a big difference when machining aluminum. They can improve the tool’s lifespan and reduce the risk of tool breakage. They also allow for increased feed rates and faster cutting by creating a thermal barrier between the bit and the workpiece.

There are several common types of coatings to consider when choosing an end mill for aluminum:

  • TiCN (Titanium Carbonitride): TiCN is a wear-resistant coating that also offers superior lubricity. It is well-suited for milling at high speeds and feeds, as well as for light-interrupted cuts.
  • AlTiN (Aluminum Titanium Nitride): AlTiN provides excellent heat resistance, making it ideal for high-speed machining, particularly on abrasive aluminum alloys.
  • Amorphous Diamond (Diamond-Like Coating): It offers better lubricity and wear resistance in aluminum and other nonferrous materials due to its sharp edges, resulting in improved results. Starlight Corp believes DLC is the best coating for the following reasons:
    • It can increase durability by 10X.
    • It offers more rigidity and reduces breakage, especially with smaller diameters.
    • The Aluminum Chip slides better on tools for efficient chip evacuation.
  • ZrN (Zirconium Nitride): Great for abrasive nonferrous alloys and less expensive than diamond coatings.
  • TiB₂ (Titanium Diboride): Prevents chip build-up on the cutting edge and is suitable for aluminum alloys.

The Number of Flutes on the End Mill

The number of flutes on an end mill is one of, if not the most, important factors when selecting the best one for your project. Aluminum is gummy and soft, which means it can stick in the flutes of your mill. While coatings can help with this issue, if you’re using a 4- or 5-flute end mill, even the best coatings won’t help. The primary purpose of flutes is to clear CNC machined chips. End mills with fewer flutes have larger slots and can remove more material at once, while those with more flutes have smaller slots and are better suited for finishing operations. Single and double-flute end mills are usually preferred when machining aluminum as they provide a good balance between roughing and finishing capabilities.

The Geometry of Flutes

When machining aluminum with a cutting tool such as an end mill, the geometry of the flutes is an important factor to consider. Geometry typically refers to its basic shape and design. It is essential to choose an end mill with the right geometry for the type of machining operation being performed. For example:

  • Flat-end mills are for profiling, slotting, and side milling.
  • Ball nose end mills are for creating rounded contours.
  • Long neck end mills are usually for pocketing, etc.

So, while the number of flutes is important, flute geometry should also be considered. The helix angle of the flutes is also important for machining aluminum. A larger helix angle helps reduce cutting forces and allows for more efficient chip evacuation but can increase chatter, leading to vibration and decreased surface finish quality. On the other hand, a smaller helix angle can provide a smoother finish but may result in higher cutting forces and less efficient chip evacuation. Check out all of our flutes right here.

Bottom Line

Aluminum is one of the most machined materials on the planet. It’s used in everything from airplanes to kitchenware to potato chip bags, and it’s also a key ingredient in many life-saving medical devices. It is an abundant metal with a relatively low cost, making it an attractive choice for manufacturers. Aluminum can be produced in large quantities with minimal energy input.

That’s why Starlight Corp exclusively offers DLC coatings, as they are the best choice for aluminum extrusion machining. Additionally, aluminum is less reactive than other metals like iron or copper, making it less prone to oxidation when exposed to air or water.

When choosing the right end mill for your aluminum machining process, consider the factors mentioned above. With a bit of research and planning, you can maximize the quality and efficiency of your machined aluminum parts.

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