With the continuous advancement of modern manufacturing technology, CNC machining has become one of the most essential processes in the manufacturing industry. Among the wide range of materials available, aluminum is particularly favored for CNC machining due to its lightweight, corrosion resistance, and excellent thermal conductivity. This article explores the advantages of aluminum in CNC machining, the aluminum alloys used by Wellcircuits CNC, the CNC machining process, and its various industrial applications.
The Advantages of Aluminum in CNC Machining
Although there is a variety of aluminum alloys with unique properties, there are certain fundamental characteristics common to all aluminum alloys.
Machinability
Aluminum can be quickly shaped, processed, and manufactured through various treatment processes. Its soft, machinable nature allows it to be easily cut by machine tools, making it more cost-effective and requiring less force than steel. These features are significant advantages for both machinists and customers. Moreover, aluminum’s excellent machinability reduces the risk of deformation during the machining process, enabling CNC machines to achieve higher precision and tighter tolerances.
Strength-to-Weight Ratio
Aluminum has a density approximately one-third that of steel, making it lightweight. Despite its low weight, it retains high strength. The balance between strength and weight is referred to as the strength-to-weight ratio. This ratio makes aluminum ideal for manufacturing parts in industries such as automotive and aerospace, where both strength and lightness are crucial.
Corrosion Resistance
Aluminum exhibits excellent resistance to corrosion and scratching in typical marine and atmospheric environments. This resistance can be further enhanced by anodization. It is important to note that corrosion resistance varies across different aluminum grades, with the general-purpose CNC machining grades typically offering the highest resistance.
Low-Temperature Performance
Many materials lose some of their desirable properties at temperatures below 0°C. For example, carbon steel and rubber may become brittle in cold conditions. However, aluminum retains its softness, ductility, and strength even at extremely low temperatures.
Conductivity
Pure aluminum has an electrical conductivity of approximately 37.7 million Siemens per meter at room temperature. While aluminum alloys typically have lower conductivity than pure aluminum, they still possess sufficient conductivity for many electronic components. However, if conductivity is not a critical factor for a machined part, aluminum may not be the best material choice.
Recyclability
As CNC machining is a subtractive manufacturing process that generates significant amounts of waste material, aluminum’s strong recyclability is highly beneficial. Recycling aluminum is energy-efficient, cost-effective, and requires less effort, making it a preferred choice for cost-conscious and environmentally responsible manufacturers.
Anodizing Potential
Anodizing is a surface treatment process that enhances the wear and corrosion resistance of aluminum. This process also simplifies the coloring of aluminum parts, further expanding their application possibilities.
Commonly Used Aluminum Alloys in Wellcircuits CNC Machining
At Wellcircuits, we commonly use the following aluminum alloys in our CNC machining services: Aluminum 6061, Aluminum 7075, Aluminum 5052, and Aluminum 2A12.
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Aluminum 6061
- Aluminum 6061 is one of the most well-known alloys, widely used across various industries due to its excellent corrosion resistance, weldability, machinability, and moderate to high strength. Its typical chemical composition includes 0.6% Si, 1.0% Mg, 0.2% Cr, 0.28% Cu, and 97.9% Al, though these values may vary slightly due to impurities or production methods.
- The density of 6061 aluminum is the same as pure aluminum (2.7 g/cm³ or 0.0975 lb/in³), and it can be strengthened through heat treatment.
- Common forms of 6061 aluminum include 6061-T6 and 6061-T4 temper grades.
- This alloy’s combination of good strength, machinability, and wear resistance makes it a versatile, general-purpose material.
- Although 6061 aluminum may not excel in any single area, it is widely used in structural materials, ship frames, radiators, chemical equipment, and even in beverage cans.
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Aluminum 7075
- Aluminum 7075 is a high-strength alloy renowned for its outstanding strength and toughness. Belonging to the 7000 series, it is often referred to as “aircraft-grade” aluminum due to its widespread use in aerospace applications.
- The primary alloying elements of 7075 aluminum include aluminum, zinc, copper, and small amounts of other elements. The composition typically includes around 90.7% aluminum, 5.6% zinc, 2.5% copper, 1.6% magnesium, and traces of other elements.
- 7075 aluminum is known for its high tensile strength (approximately 572 MPa or 83 ksi) and yield strength (around 503 MPa or 73 ksi), making it one of the strongest aluminum alloys.
- In addition to its high strength, 7075 aluminum also offers good toughness, making it suitable for applications where both strength and impact resistance are critical.
- Due to its excellent strength-to-weight ratio, 7075 is commonly used in aerospace components, such as wings and fuselage parts. It is also used in high-performance bicycles, climbing equipment, and select firearm components. However, 7075 aluminum is more difficult to machine compared to other alloys, requiring precise tools and cutting conditions. Heat treatment, including solution heat treatment and artificial aging, can further improve its properties.
- Although 7075 aluminum has good corrosion resistance, it is not as resistant as alloys like 6061. It is recommended to apply protective coatings or treatments in corrosive environments.
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Aluminum 5052
- Aluminum 5052 offers excellent weldability, machinability, and outstanding resistance to saltwater corrosion. It is a non-heat-treatable alloy and can be strengthened through work-hardening processes, with 5052-H32 being the most common temper. 5052 is one of the strongest non-heat-treatable alloys, making it ideal for applications requiring excellent formability and weldability.
- Its density is slightly lower than pure aluminum (2.68 g/cm³ or 0.0968 lb/in³), and its chemical composition includes 2.5% magnesium, 0.25% chromium, and 97.25% aluminum. Unlike some aluminum alloys, 5052 does not contain copper, giving it superior resistance to saltwater corrosion. This makes it ideal for marine applications, as well as for use in electronic enclosures, signage, pressure vessels, and medical equipment.
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Aluminum 2A12
- Aluminum 2A12 is a high-strength alloy from the 2xxx series, primarily alloyed with copper. It is known for its excellent strength, making it comparable to certain steels. The typical composition includes around 90.7% aluminum, 3.8-4.9% copper, 1.2-1.8% manganese, 1.2-1.8% magnesium, and
