CNC machining is famous in the manufacturing world for being accurate, fast, and consistent. Its precise cutting and computer-automated machinery allow it to repeatedly make high-volume batches with ease, reduce the risk of human error, and be compatible with a vast assortment of materials.
Whether it’s steel, acrylic, or even wood or foam, CNC machines can make a range of turned parts that meet your every need. So why are CNC aluminium parts so popular?
Why use aluminium for CNC machining?
Aluminium is considered one of the most machined materials. An ever-growing number of industries are manufacturing CNC-machined aluminium parts, which isn’t surprising considering the fantastic results they produce.
Its desirable physical properties, versatility, and range of alloys enable these results. By creating aluminium machined parts with CNC machining’s speed and detail, you can successfully create durable and consistent products that meet quality standards time and time again. This is ideal for parts that must conform to specific regulations, making it suitable for use across many applications and industries.
Applications
Since aluminium is easy to shape, it is suitable for constructing a wide range of components and can be used for multiple purposes.
Aluminium is generally favoured for aerospace, automotive, and electronic parts due to its strength, lightweight structure, and electronic conductivity. For aerospace applications, it is often used for aircraft fittings and landing gear, while it is a reliable material for shafts, engine components, and suspension systems in automotive settings. Aluminium is also handy for audio equipment, camera parts, and other consumer electronics, especially when creating sleek designs.
Grades and alloys
Aluminium isn’t only valuable for its purest form. Combined with other metals, it makes a fantastic base material for many alloys.
Aluminium alloys are sorted into categories. These are broken down into numerous series, though the first seven are used most frequently for manufacturing. Within each series, the aluminium alloys are given a number or grade. There are plenty of grades of aluminium out there, all with suitability designed to fit different uses. The closer the grade, the more similar the materials are and the more properties they’ll share.
While you’ll want to find the perfect grade of aluminium to suit your specific needs, there are two crowd favourites for CNC machining: 6061 aluminium alloy and 7075 aluminium alloy.
6061 aluminium alloy
- Medium-strength — suitable for various industries
- Versatile, workable and weldable
- High corrosion resistance
- Heat-treatable
- Many ways to machine it
7075 aluminium alloy
- One of the strongest aluminium alloys
- Suited to high-stress applications
- Excellent for machining complex parts
- Favoured by the aerospace industry
Why do CNC machining and aluminium work so well together?
Aluminium and CNC machining are fantastic pairings for a variety of reasons.
Since CNC machines are programmed with the relevant files and G-code, they can achieve intricate detailing and complex geometries, especially with aluminium. This workable material can be effectively shaped with the rotating cutting tools used in CNC machines, carving and forming the required parts quickly and efficiently.
Aluminium has fantastic mechanical qualities, making it perfect for different CNC machining processes — including milling, drilling, and turning. This flexibility makes it an accessible material for various manufacturers with varying machines across different industries and an excellent choice for design freedom.
Advantages of aluminium CNC machining
Aluminium CNC machining offers a whole host of advantages, making it a brilliant option for versatile and long-lasting components.
Quick to machine
One significant benefit of CNC aluminium parts is how quick and easy they are to machine. Since aluminium has high dimensional stability and is less dense than other materials like steel, it chips easily. This means manufacturers can cut away at it quickly while successfully keeping residual stress in check.
Aluminium also cools quickly, requiring less coolant and further reducing lengthy machining processes. This also lowers costs for your parts, especially considering that aluminium and its alloys can be less expensive than similar materials. As a result, it is a cost-effective choice for any industry.
Corrosion resistance
Since aluminium has a natural corrosion resistance, CNC-machined aluminium parts are ideal for different environments and can withstand humidity from the get-go. They prove favourable in marine settings and wet conditions. That said, various grades of aluminium will offer different levels of corrosion resistance — for this reason, you’ll want to find the one that best suits your parts.
Weight
With an impressive strength-to-weight ratio, aluminium parts are perfect for applications that require durability without the extra weight. Aluminium can replace heavier metals with practical and durable parts thanks to their strong but lightweight structures.
As previously mentioned, aluminium’s natural corrosion resistance means there’s less need to add extra weight to parts with the heavy anti-corrosion coatings that are essential for other materials. However, depending on the grade of aluminium, additional coatings might be necessary for suitability in specific applications.
Surface finishes
Another benefit of CNC aluminium parts is the versatility of finishing options.
Aluminium is naturally sleek, but carbide tooling and modern coolants can be used during the manufacturing process for extra smooth silver finishes. This makes aluminium parts perfect for electronic devices, including smartphones and laptops, as well as structural supports.
Where appearance is important, aluminium parts can also be given a matt finish with bead blasting or anodised to ensure a seamless design. This also increases surface hardness and provides extra corrosion resistance for long-term use.
Other benefits of aluminium CNC machining
Aluminium is non-toxic and malleable in nature. It can be completely recycled after use as it retains most of its properties, making it perfect for industries looking to boost sustainability.
Aluminium parts are also great conductors of electricity, more than carbon and stainless-steel parts. Its alloys also make good conductors, but less so than pure aluminium. Still, they are excellent choices for electrical components.
Are there any drawbacks of aluminium CNC machining?
Despite their many advantages, CNC-machined aluminium parts also have their suitability factors to consider for every use/project. Before starting your project, you should always weigh the pros and cons to prepare for any difficulties.
Hardness
While it has an excellent strength-to-weight ratio, aluminium is not as hard as other materials like steel. Because of this, it might not be the best choice for high-impact or high-load-bearing parts.
Overheating
Aluminium has a lower melting point than materials like steel, so it is only sometimes practical when exposed to extremely high heat and a high coefficient of thermal expansion. Due to this, parts can deform if they get too hot during the machining process.
Wear and tear
Aluminium parts can also damage tools when machining. Since the material is highly malleable, this can result in material build-up, which makes cutting tools duller and quicker. Because of this, tools might need to be swapped out and changed to avoid low-quality surface finishes, which can be expensive and time-consuming.
Can you fix these issues?
While aluminium parts might present a few difficulties, it doesn’t mean they’re impractical. There’s a reason they’re so popular; after all — sometimes, it just takes a little trial and error.
To prevent overheating, you can use high-pressure coolant systems. This prevents your CNC machine from getting too hot throughout manufacturing. You can also reduce the cutting speed to generate less heat. This can avoid thermal expansion of the workpiece and lower the chances of distortion.
When it comes to the wear and tear of cutting tools, the easiest thing to do is keep checking them throughout the manufacturing process. By keeping on top of this, you can avoid breakages before they happen and limit wear.
A quick recap of aluminium CNC machining
By now, you’ll know that aluminium and its alloys (particularly 6061 and 7075) are great additions to your manufacturing arsenal.
Aluminium’s status as a ‘Jack of all trades’ material makes it an excellent match for CNC machining. Its workability and strong mechanical qualities, combined with CNC machines’ speed, accuracy and consistency, allow for rapid manufacturing and design freedom.
Among other things, CNC aluminium parts’ versatility, machinability, strength-to-weight ratio and corrosion resistance make them a better choice than most materials across a wide range of applications and industries, from aerospace to electronics.
Of course, the untrained mind may be confused by aluminium’s range of alloys and applications. The categories and series into which alloys are sorted are helpful, so be sure to use them when looking for the right kind of aluminium for your needs.
CNC aluminium parts can present a handful of minor issues. Aluminium’s inferior durability to steel, the risk of overheating, and potential damage to tools are all things to keep in mind. But don’t write it off; you can adapt to these by being careful and using coolant when needed.
While aluminium is a fantastic option for CNC machined parts, selecting a suitable material is crucial.
Supporting UK businesses
Are you looking for support with your project? Sheldon Precision is here to help. With an entire CNC manufacturing facility, we provide a premium service that meets exact customer specifications.
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