Milling aluminum effectively requires using sharp, specialized tools and appropriate techniques to manage its unique properties. Start by selecting carbide-tipped end mills with 2 or 3 flutes and a high helix angle (40° or more) for efficient chip evacuation. Proper lubrication with cutting fluid is crucial to minimize heat buildup and prevent the aluminum from sticking to the tool. Use high spindle speeds (500-1500 SFM depending on the alloy) and moderate feed rates, adjusting based on the specific aluminum alloy. Secure the workpiece firmly and consider using climb milling to improve surface finish. For optimal results, prioritize sharp tools, consistent lubrication, and precise speed and feed settings.
Key Takeaways
What are the Advantages of Aluminum for Milling?
The main advantage of aluminum is that it has several properties that make it ideal for milling. For one, Aluminum material is soft and malleable, which means it can be easily shaped in a machine. Furthermore, aluminum has emerged as a preferred material for prototypes as it is inexpensive and easy to work with.
Aluminum is lightweight, strong, and corrosion-resistant. These properties make aluminum an excellent choice for various applications, including automobile parts to aircraft construction. In addition, aluminum is also non-magnetic and has a high thermal conductivity.
This makes it ideal for electrical applications where heat needs to be quickly dissipated. Overall, aluminum is an excellent choice for milling due to its combination of properties. However, in some cases, you may also need die casting services for creating custom aluminum parts with complex shapes that would be difficult or cost-prohibitive to mill directly. This process can be highly efficient for producing larger volumes of parts while maintaining precision and quality.
Performance Table of Commonly Used Aluminum Alloy
Alloy | Condition | Physical Properties | ||||
| Melting temperature range ℃ | The conductivity of electricity 20℃ IACS % | The conductivity of heat cal/℃-cm-sec | Coefficient of linear expansion | Longitudinal elastic coefficient | ||
| 1060 | 0 | 646-657 | 62 | 0.56 | 23.8 | 7 |
| 1070 | 0 | 646-657 | 62 | 0.56 | 24 | 7 |
| 1100 | 0 | 643-657 | 59 | 0.5 | 23.6 | 7 |
| 2017 | T4 | 513-640 | 34 | 0.32 | 23.6 | 7.4 |
| 2024 | T4 | 502-638 | 30 | 0.29 | 23.2 | 7.5 |
| 2A12 | T4 | 500-635 | 30 | 0.29 | 23.2 | 7.4 |
| 2A50 | T4 | 510-640 | 34 | 0.32 | 23.6 | 7.4 |
| 3003 | 0 | 643-654 | 50 | 0.46 | 23.2 | 7 |
| 3004 | 0 | 629-654 | 42 | 0.39 | 24 | 7 |
| 3A21 | 0 | 640-654 | 50 | 0.46 | 23.2 | 7 |
| 5052 | H34 | 607-649 | 35 | 0.33 | 23.8 | 7.2 |
| 5083 | H112 | 600-640 | 35 | 0.33 | 23.4 | 7 |
| 5182 | H111 | 604-645 | 34 | 33 | 23.6 | 7 |
| 5754 | H111 | 568-628 | 27 | 0.26 | 24.3 | 7 |
| 5A06 | H112 | 600-640 | 35 | 0.33 | 23.4 | 7 |
| 6060 | T6 | 580-650 | 42 | 0.4 | 23.4 | 7 |
| 6061 | T6 | 582-652 | 43 | 0.4 | 23.6 | 7 |
| 6063 | T6 | 615-655 | 55 | 0.5 | 23.4 | 7 |
| 6082 | T6 | 581-650 | 42 | 0.4 | 23.4 | 7 |
| 6A02 | T6 | 581-650 | 42 | 0.4 | 23.4 | 7 |
| 7075 | T6 | 477-635 | 33 | 0.31 | 23.6 | 7.3 |
| 7050 | T6 | 620-650 | 37 | 0.36 | 23.4 | 7.3 |
The Materials for Aluminum Milling
Milling aluminum is removing material from an aluminum workpiece using a milling machine. There are many types of aluminum, and each type has its own aspects that must be taken into account when milling. There are numerous considerations to make when selecting the ideal material for a project.
For instance, you’ll be required to consider the material’s strength and how easy it is to work with. Aluminum is available in two major types: cast and wrought. Wrought aluminum is stronger and can handle heat better than cast aluminum, but it is also more expensive.
Cast aluminum, on the other hand, is more flexible but less strong. In the end, the aluminum type you use will rely on what your project needs. When milling aluminum, it is important to use the correct cutting tools and strategies to avoid damaging the material.
What are the Challenges Of Milling Aluminum?
The main challenge of milling aluminum is that it’s a sticky material that can easily melt and fuse to the tool. To mill aluminum effectively, it is important to keep the tools very sharp and to be careful when cutting. Additionally, aluminum is a difficult material to mill due to the amount of friction and heat generated during the process.
This friction and heat can damage the tool and the workpiece if not managed properly. The aluminum chips produced by the milling process can also be very dangerous if they are inhaled, so worker safety is a major concern. The use of a well-planned process and using high-quality tools can help prevent these issues. With proper planning and execution, milling aluminum can feel like a worthwhile and productive endeavor.
Aluminum Milling Know-How
Tools Geometry
Regarding tooling, there are a few different coating options available. One of the most chosen options is ZrN, a gold-colored coating. Another option is TiB2, a less well-known but highly effective coating. Both of these coatings help to improve the lifespan of the tooling and increase its efficiency.
Furthermore, they can also assist in enhancing the overall performance of the tooling by reducing friction and wear. Eventually, the choice of coating depends on the individual requirements of the tooling application but the primary factor to high performance when machining aluminum is the right flute count and helix angle for your job.
Flute Count
For milling aluminum, there are two main types of end mills that you can choose from 2 flutes and 3 flutes. The debate over whether to use a 2-flute or 3-flute end mill for aluminum has raged on for years. Both have pros and cons, but it comes down to personal preference.
Different operations and rigidity can also affect the choice of tool. 2 flutes are the best choice for aluminum because of the big chip it leaves behind. 3 flutes are better for finishing tasks and can work well as routers with the right settings. It is always up to the person to determine which option is optimal for him.
Helix Angles
An instrument’s helix angle is defined as the degree to which the tool’s longitudinal axis deviates from a straight line perpendicular to the cutting edge. The optimum helix angle for a given application depends on several factors, including the material being cut and the desired finish. For conventional roughing and slotting, a 35 or 40-degree helix angle is typically recommended.
These angles provide a good balance between cutting speed and chip clearance. However, a higher helix angle (45°) is often used for finishing operations. This provides more aggressive cutting action and helps to reduce harmonics and chatter. When choosing a tool for aluminum machining, it is important to select one with the appropriate helix angle. Higher helix angles (40° or above) are typically best for this material, as they provide better chip clearance and help to prevent premature tool wear.
Options For Tooling
Most of the time, 2-flute or 3-flute standard tools are enough to machine aluminum. But for some application domains and machine arrangements, there are a few more tooling choices to consider if you want to get even better results.
Chipbreaker Tooling
When machining aluminum, chip evacuation is essential to keep in mind. Two- and three-flute end mills can do a good job removing chips, but using a 3-flute chip breaker tool can produce even better results. The chip breaker’s offset geometry creates smaller chips that are easier to remove while leaving a smooth surface.
Another important tool for machining aluminum is high-efficiency milling. This technique uses specialized toolpaths to increase material removal rates while reducing wear on the cutting tools. As a result, milling can help reduce machining costs and improve part quality. Combined with the right chip breaker tooling, it can help create an efficient and effective process for machining aluminum parts.
Cutting Tools for Aluminum Milling
High Balance End Mills
These are designed to improve performance in machining centers that are already well-balanced and can run at high RPMs and feed rates. These tools are perfectly balanced for machining aluminum at high speed (up to 33,000 RPM). Helical Solutions has both standard 2-flute and coolant-through 3-flute high-balance tools. The coolant-through 3-flute tools reduce heat, improve chip removal, and increase material removal rates. Like the chip breakers, these tools are also a great option for high efficiency.
Milling Toolpaths
High-balance end mills can help improve productivity in any machining center, but they are especially well suited for aluminum machining. With their perfect balance and high-speed capabilities, these tools can help you get the most out of your machining center.
Running Parameters
When machining aluminum, setting the right parameters to get the most out of your work is important. Some broad guidelines should be observed, although the parameters for each job also depend on many other factors. For cast aluminum alloys like 308, 356, and 380, the surface footage should be between 500 and 1000 SFM. The RPMs should also change based on the diameter of the cutter, using the formula (3.82 x SFM) / Diameter. In wrought aluminum alloys, like 2024, 6061, and 7075, the surface footage should be between 800 and 1500 SFM. There are many other factors to consider when setting parameters for aluminum machining jobs, but following these general guidelines is a good place to start.
High-Efficiency Milling
High-efficiency milling, or HEM, is a machining strategy that is becoming increasingly popular in manufacturing. It is a roughing technique that uses both a high ADOC and low RDOC (a high Axial Depth of Cut and Radial Depth of Cut) to take full advantage of the tool’s cutting edge. This allows for greater efficiency, extended tool life, and better performance overall, especially when machining aluminum. Many CAM programs now offer HEM toolpaths, though any machine can technically perform HEM if the CNC controller features a fast processor.
How to Mill Aluminum | FAQs
What is milling aluminum?
Milling aluminum is a CNC machining process that removes material from an aluminum workpiece to form precise components. Its popularity stems from aluminum’s lightweight, high machinability, and cost-effectiveness. This process is widely used in aerospace, automotive, and consumer electronics.
Which aluminum alloys are best for milling?
Aluminum alloys from the 6000 series (such as 6061 and 6082) are widely used because they offer an excellent balance of strength, corrosion resistance, and ease of machining. The 7000 series (e.g., 7075) provides higher strength but may require more precise machining and careful parameter control.
What are the best tools for milling aluminum?
For best results, use carbide end mills designed specifically for aluminum. Look for:
- Flute Count: 2–3 flutes allow effective chip clearance.
- Helix Angle: A high helix angle (around 40°–45°) reduces cutting forces and improves chip evacuation.
- Coatings: Consider TiB₂ or polished tools to minimize built‑up edge (BUE).
