The 5 Most Common Aluminum Alloys for CNC Machining: A Complete Guide

Aluminum alloys have become the material of choice in CNC machining due to their excellent density-to-strength ratio and exceptional machinability. CNC aluminum machining delivers both the precision required for complex parts and the efficiency needed for high-volume production.

There are many different grades of aluminum alloys available on the market. Different countries and regions use different standard designation systems, such as GB (China), AA/ASTM (USA), EN AW (Europe), and JIS (Japan). Engineers need to understand the specific properties of these aluminum alloy grades to find the material that best meets the project requirements.

LVMA CNC presents this comprehensive guide to the five most popular aluminum alloys for CNC machining, detailing their unique properties, applications, and important considerations for each material.

6061-T6 Aluminum: The Industry Standard

6061-T6 stands as one of the most widely used aluminum alloys in the CNC machining industry, and for good reason. This versatile grade offers an excellent balance between strength, machinability, and dimensional stability, making it the go-to choice for countless applications.

Key Properties:

• Outstanding machinability with close tolerances
• Good corrosion resistance
• Excellent weldability
• It has a density of approximately 2.70 g/cm³ and moderate strength.
• Cost-effective

Common Applications: The versatility of 6061-T6 makes it suitable for diverse industries. Engineers regularly specify this alloy for automotive chassis components, bicycle frames, valve bodies, computer parts, and general structural applications. Its widespread availability and ease of processing make it an ideal choice for both prototyping and production runs.

7075-T6 Aluminum: The High-Performance Choice

7075-T6 has a density of approximately 2.80 g/cm³, and possesses higher strength than 6061-T6. This high-strength alloy is the material of choice for critical components used in harsh environments.

Key Properties:

• Exceptional strength-to-weight ratio
• Superior fatigue resistance
• Excellent corrosion resistance when properly treated
• Higher hardness than most aluminum alloys

Common Applications: The aerospace and military industries rely heavily on 7075-T6 for aircraft fittings, missile components, and fuse parts. Its high strength makes it ideal for structural components that must withstand extreme loads.

Important Considerations: Engineers should note that 7075-T6 comes with tradeoffs. This grade commands a higher price point compared to other aluminum alloys and offers less flexibility. The material is more prone to cracking and exhibits lower elasticity, requiring careful consideration during the design phase.

2024-T4 Aluminum: The Aerospace Specialist

2024-T4 aluminum alloy is the standard material for sheet metal, plates, and extrusions across various industries. For CNC aluminum alloy parts used in high-temperature environments, we typically recommend this grade. This alloy performs exceptionally well at high temperatures, meeting both strength and purity requirements.

Key Properties:

• High strength at elevated temperatures
• Excellent purity
• Good machinability
• Superior fatigue resistance

Common Applications: 2024-T4 alloy is commonly used in some external parts of aircraft, as well as components of transport vehicles. Inside aircraft, it is primarily used for tie rods.

Important Considerations: 2024-T4 aluminum alloy has relatively low corrosion resistance and is susceptible to corrosion from acids, alkalis, and seawater. Its high thermal conductivity also causes parts to become brittle after heat treatment, requiring specific processing techniques.

MIC 6 Aluminum: The Precision Platform

If your project requires high stability and tight tolerances, our engineers typically recommend MIC 6. This cast aluminum sheet is based on a 7000 series cast aging alloy with a density of approximately 2.70 g/cm³. It offers dimensional stability and good flatness.

Key Properties:

• Superior flatness and dimensional stability
• Excellent strength-to-weight ratio
• Outstanding precision capabilities
• Good elasticity
• Excellent thermal stability
• Relatively easy to machine

Common Applications: MIC 6 is the material of choice for precision tooling plates, machine bases, fixtures, and applications where dimensional stability is critical throughout the machining process.

Important Considerations: The primary limitation of MIC 6 is thread strength. Threads cut in this material are not as robust as those in other aluminum grades, which can lead to premature thread failure. Engineers must account for this limitation during the material selection phase, particularly for applications involving threaded connections.

6082 Aluminum: The Structural Workhorse

6082 aluminum offers high tensile strength combined with excellent corrosion resistance, making it an attractive option for manufacturers seeking enhanced performance at a competitive price point.

Key Properties:

• High tensile strength
• Excellent corrosion resistance
• Good toughness
• Cost-effective alternative to higher-grade alloys
• Suitable for general-purpose applications

Common Applications:In the construction industry, structural components such as bridges, towers and trusses are mainly made of 6082 aluminum alloy. The structural components in the construction industry require both strength and corrosion resistance, so 6082 aluminum alloy is an ideal choice.

Important Considerations: Our engineers often encounter thin-walled components. Due to the relatively high strength of 6082 aluminum alloy, it is not very suitable for processing complex thin-walled designs.

Conclusion

When machining aluminum by CNC machining, we typically need to consider various factors, including strength requirements, environmental conditions, budget constraints, and machinability. This article can help you gain a basic understanding of the characteristics of five main aluminum materials to achieve better results.