Aluminium Alloy for CNC machining

CNC machining of Aluminium alloy offers a range of advantages due to the material’s specific properties.

Aluminium alloys for CNC machining offers a range of advantages due to the material’s excellent mechanical properties and versatility. Hence, Aluminium alloys are one of the most popular materials for CNC machining for milling and turning.

However, there are many different aluminium alloy types in the market. Therefore, selecting the adequate type of aluminium alloy for a specific application takes time and effort.

Nevertheless, it is possible to select wisely by knowing the properties of aluminium in detail, its benefits for CNC machined parts, and the differences between the most popular types of aluminium alloys for CNC machining.

Mechanical properties of aluminium alloys for CNC machining

Aluminium alloys, with their diverse mechanical properties, are not only an excellent choice for CNC machining but also a key consideration when designing for CNC machining. Their machinability and versatility make them ideal for numerous applications, from aerospace components to consumer products, where material selection is critical to achieving optimal performance and manufacturability.

Here are the most relevant mechanical properties of aluminium alloys for CNC machining:

• Tensile strength
• Hardness
• Machinability
• Ductility
• Fatigue resistance

How to choose the Aluminium alloy for CNC Machining

The details of the most common aluminium alloys for machining and why they are among the best materials for different applications should be precise. Now, the best way to select the best type of aluminium alloy for a specific

Application is to make an informed choice. Therefore, it is crucial to understand the application requirements. By following five steps, we can obtain the necessary information to choose. These are the steps:

1. Strength – Verify the strength requirement. This step helps to discard some of the aluminium alloy types for machining and select within a smaller range.
2. Corrosion Resistance – Verify whether corrosion resistance is a must. This step involves whether the part or parts will operate in harsh environments or be in contact with chemicals. In such a case, a special alloy such as the 5000 series may be more suitable than a standard 6061.
3. Machinability – Here, we must consider the need to achieve a complex geometry. If so, we can immediately discard the 5083, for example.
4. Weldability – Consider weldability. Similar to the previous point, it is vital to consider if welding is required to assemble the parts. Welding might create issues even when the 7075 alloys provide the application’s strength.
5. Heat Treatability – Consider heat treatability and other post-processing. In cases where we need to sacrifice one property to get another, post-processing might be the solution. However, only some alloys are suitable for heat treatment and other post-processing options. Therefore, confirming that post-procession is possible becomes critical before making any choice.

Finding the perfect balance might be complicated. Yet, by combining the requirements mentioned above, it will be easier to identify the aluminium alloy types for machining that will be suitable for a specific project. The last step would be ensuring the available budget covers the material needed.

Aluminium alloy for CNC machining comparison

Benefits of using aluminium for CNC machined parts

Aluminium alloys offer numerous benefits when it comes to CNC machined parts. Here are some of the most notable:

• Lightweight yet strong – Aluminium alloys are known for their high strength-to-weight ratio, making them ideal for creating sturdy yet lightweight parts. Aluminium alloys are significantly lighter than most other metals, including steel and copper. Therefore, engineers use these alloys in applications where weight is crucial, such as the aerospace, automotive industries, and sporting goods production.
• Corrosion-resistant – Aluminium alloys are naturally corrosion-resistant, which is a significant advantage in many applications where parts operate in harsh environments, such as marine and offshore applications.
• Excellent machinability – Aluminium is an easy-to-machine metal because of its low melting point. High cutting speeds are achievable with low tool wear. This results in quicker cycle times and lower costs.
• Recyclable – Aluminium is highly recyclable, which makes it an eco-friendly option for CNC-machined parts. This property also makes these alloys more cost-effective than many other metals.
• Excellent Fatigue Strength – Aluminium alloy possesses excellent fatigue resistance, making it a good choice for components subject to repetitive loading and unloading.

In addition to these benefits, aluminium alloys offer good electrical and thermal conductivity while being non-toxic and non-magnetic.

Overall, using aluminium alloys for CNC machined parts provides an excellent combination of strength, durability, and versatility, making it a popular choice in many industries.

Common Aluminium Alloy for machining

As mentioned before, several aluminium alloys are available in the market, and it is essential to understand their differences to choose the most adequate one for your specific application.

There are seven different aluminium alloys used in the industry. Each aluminium alloy series starts with a number representing the primary alloying element added to the pure aluminium. The following are the main aluminium alloy series used in CNC machining.

• Aluminium alloy 2000 series – Aluminium alloys in the 2000 series are moderate to high-strength materials that contain copper as the primary alloying element, with other elements such as Magnesium sometimes specified within the series. Product designers use Aluminium alloy 2000 series alloys for aircraft parts where high strength is critical.
• Aluminium alloy 3000 series – Its primary alloying element is manganese and provides good corrosion resistance and moderate strength compared to other aluminium alloys. These alloys are non-heat treatable.
• Aluminium alloy 5000 series – Aluminium alloys in the 5000 series have Magnesium as the primary alloying element. Also, they are outstanding at corrosion resistance. Applications where machined parts operate in harsh environments, such as marine and chemical applications, use both the 5052 and the 5083 alloys.
• Aluminium alloy 6000 series – Aluminium alloys in the 6000 series have Magnesium and silicon as the main alloying elements. Most common aluminium alloy for machining is 6061-T6 and 6082-T6.
• Aluminium alloy 7000 series – Alloys in this series contain Zinc as the primary alloying element, and they are known as “aerospace-grade” aluminium types because their main properties include outstanding ultimate tensile strength and yield strengths that surpass 500 MPa. They also have an excellent strength-to-weight ratio and high fatigue resistance. However, these alloys can be costly and need better weldability.

Aluminium Alloy 2011

Aluminium Alloy 2011 has copper as its primary alloying element and is known for its excellent machinability, often called Free Machining Alloy (FMA). The presence of Lead in the alloy improves its machinability, allowing product designers to create high-precision intricate parts.

• Excellent machinability
• High strength
• High Thermal Conductivity
• Limited weldability
• Moderate corrosion resistance – Anodise the parts to increase resistance
• Temper options – T3, T4, T8

Product designers use Aluminium alloy 2011 for complex, intricate parts manufactured by automated manufacturing to produce appliance parts, automotive trims, fasteners, and fittings

Chemical Composition

Properties of Aluminium Alloy 2011-T8

Aluminium Alloy 2014

Aluminium alloy 2014 is known for its excellent machinability and has copper as its principal alloying element. It is the second most popular alloy after the 2024 in 2000 series. The 2014 alloy can be heat treated to improve mechanical properties and hardened to reach strengths similar to steel.

• High strength
• High Electrical Conductivity
• Fair Weldability
• Limited corrosion resistance
• Good machinability
• Temper options – T3, T4, T6 & T651/T6511

Due to its high strength-to-weight ratio and good machinability, engineering designers often use aluminium alloy 2014 in aerospace applications such as aircraft components and structural elements.

Chemical Composition

Properties of Aluminium Alloy 2014-T6, T651

Aluminium Alloy 2017

Aluminium alloy 2017 is a high-strength, heat-treatable alloy with copper as its primary alloying element. It has better ductility and formability properties compared to 2014. Aluminium alloy 2017 has excellent machinability in the T4 temper.

• High strength
• Heat treatable
• High Electrical Conductivity
• Fair Weldability
• Moderate corrosion resistance
• Good machinability
• Temper options – T4,T451 & T4510

Product designers often use Aluminium alloy 2017 in high-strength structural parts, aircraft components, military equipment and rivets.

Chemical Composition

Properties of Aluminium Alloy 2017-T4, T451

Aluminium Alloy 2024

Due to its excellent mechanical properties, automotive and aerospace industries frequently use aluminium alloy 2024. Compared to alloys 6061 and 7075, 2024 has lower corrosion resistance.

• Excellent fatigue resistance
• High strength
• Heat treatable
• High Electrical Conductivity
• Only suitable for friction welding
• Moderate corrosion resistance
• Good machinability
• Temper options – T3,T4,T6 & T351

2024 alloy produces aircraft structures, fuselage, and wing elements. Engineers also use it in high-stress applications such as automotive, machinery and sports equipment. 

Chemical Composition

Properties of Aluminium Alloy 2024-T4, T451

Aluminium Alloy 3003

Aluminium alloy 3003 is a non-heat treatable alloy primarily composed of manganese as its primary alloying element. It is generally used for sheet metal products, but thicker plates can be machined.

• Corrosion resistance
• Non-heat treatable
• Moderate machinability
• Good formability
• Good weldability
• Moderate strength
• Temper grades – H12, H14, H16, H18, H22

Due to its excellent formability and corrosion resistance, product designers use 3003 alloys in Radiators, HVAC systems, heat exchangers and chemical equipment.

Chemical Composition

Properties of Aluminium Alloy 3003-H18

Aluminium Alloy 5052

Aluminium alloy 5052 has Magnesium as its primary alloying element and is a non-heat treatable alloy. These alloys are known for their excellent corrosion, good formability and moderate strength. Alloy 5052

• Corrosion resistance
• Good formability
• No-heat treatable
• Good weldability
• Moderate machineability
• Temper grades – H32, H34, H36 & H38

Alloy 5052 is used in applications exposed to moisture and marine applications due to its exceptional resistance to corrosion in marine and saltwater environments.

Chemical Composition

Properties of Aluminium Alloy 5052-H32

Aluminium Alloy 5083

Aluminium alloy 5083 is a non-heat treatable alloy with Magnesium as its primary alloying element. Aluminium alloy 5083 is known for its exceptional corrosion resistance, high strength and good weldability. Due to its high strength, it is moderately challenging to machine complex intricate designs.

• Excellent corrosion resistance
• High strength
• Excellent weldability
• No-heat treatable
• Temper grades – O, H32, H34, H36<H38 & H116

Due to its high strength and high corrosion resistance in marine environments, engineers use Alloy 5083 in marine and naval applications such as Ship hulls and bulkheads, Offshore platforms, boats, yachts and submarine parts.

Chemical Composition

Properties of Aluminium Alloy 5083-H321

Aluminium Alloy 6061

Aluminium alloy 6061 is widely used due to its high strength, excellent formability and corrosion resistance. Alloy 6061 has Magnesium and silicon as the main alloying elements. Due to their comparably lower cost and excellent machinability, they are one of the most common aluminium alloys used for machining.

• High strength
• Good formability
• Heat treatable
• Excellent machinability
• Good corrosion resistance
• Tempera grades – T6, T651, T4 & O

Due to the above properties, engineers use aluminium alloy 6061 for aerospace components, automotive parts, bicycle frames and marine components.

Chemical Composition

Properties of Aluminium Alloy 6061-T6, T651

Aluminium Alloy 6063

Aluminium Alloy 6063 has Magnesium and silicon as the main alloying elements and is typically used for architectural applications. Temper grade 6063-T6 is the most common and has good machinability.

• Excellent machinability
• Good formability – T4 temper grade
• Heat treatable
• Corrosion resistance
• Temper grades – T6, T651, T4 & O

Alloy 6063 is used in architectural and structural applications such as window and door frames, handrails, furniture frames and structural components.

 Chemical Composition

Properties of Aluminium Alloy 6063-T6

Aluminium Alloy 6082

Aluminium alloy 6082 has the highest strength of all the 6000 series alloys. In Plate form, 6082 alloy is the most common type used for machining due to its ease of machining. It is comparably stronger than 6061. Increased amounts of manganese help control the grain structure, resulting in a stronger alloy.

• High strength
• Good corrosion resistance ( Less than 5052 & 5083)
• Heat treatable
• Good machinability – Choose T6 & T651
• Temper grades -= T6, T651, &T4

Alloy 6082 is used in structural components, automotive components, marine applications and general machining.

Chemical Composition

Properties of Aluminium Alloy 6082-T6

Aluminium Alloy 7050

Generally known as commercial aerospace alloy, 7075 uses Zinc as its primary alloying element. Aluminium alloy 7050 is used in aerospace due to its high fatigue strength, high strength and high resistance to stress corrosion cracking.

• High strength
• Strong mechanical strength
• Good toughness and stress corrosion cracking resistance
• Temper grades – T7651 & T7451

Chemical Composition

Properties of Aluminium Alloy 7050-T7651

Aluminium Alloy 7075

Aluminium alloy 7075 is a high-strength alloy known for its exceptional strength-to-weight ratio and excellent mechanical properties. 7075 uses Zinc as its primary alloying element.

• Excellent fatigue ressistance
• Low corrosion resistance
• Heat treatable
• High strength
• Temper grades – T6, T651, T73, T7351 & O

Due to 7075 alloy’s excellent mechanical properties, engineers use the alloy for aerospace components, fuselage frames, aircraft structures, high-stress structural applications, military equipment and defence applications, bicycle frames and high-performance machinery.

Chemical Composition

Properties of Aluminium Alloy 7075-T6, T651