CNC machining of aluminum: how it is done and why it is used

In modern industry, the search for materials that offer lightness without sacrificing strength is constant. Aluminum, combined with numerical control technology, has become a top-tier solution for demanding sectors such as aerospace, automotive and electronics. But how is a block of this metal transformed into a high-precision component? CNC machining of aluminum is a subtractive process in which machinery, guided by advanced software, removes material in a controlled way to create parts with complex geometries and micrometric tolerances.

This article is a complete guide to why aluminum is the material of choice for machining, the advantages of this combination and the key processes used to manufacture everything from a structural aircraft component to a smartphone housing. Discover how CNC technology and aluminum can optimize your production and competitiveness.

Why is aluminum machined with CNC?

Aluminum is not a popular material by chance. Its intrinsic properties make it an ideal candidate for subtractive manufacturing processes, and CNC technology is the perfect tool for exploiting its full potential.

The main reasons lie in its exceptional combination of physical and mechanical properties:

• Excellent strength-to-weight ratio: With a density almost three times lower than steel, aluminum makes it possible to produce significantly lighter parts. Through alloying, mechanical strengths comparable to some steels can be achieved, which is critical in industries such as aerospace and automotive, where reducing weight means efficiency.

• High machinability: Machinability is defined as the ease with which a material can be cut. Aluminum is one of the most machinable metals, allowing high cutting speeds and feeds. This translates directly into a higher material removal rate, shorter production cycles and, consequently, lower operating costs.

• Superior thermal conductivity: Aluminum dissipates heat very efficiently. During machining, this property helps to carry heat away from the cutting zone, protecting the tool from premature wear and minimizing the risk of part distortion.

• Corrosion resistance: Thanks to a natural process called passivation, aluminum forms a thin oxide layer on its surface that protects it from oxidation and other chemical agents. This ensures greater part durability, even without additional surface treatments.

Vurcon expert tips for machining aluminum

As your technical partner, we share some practical tips to maximize your results:

• For an optimal surface finish, use 2- or 3-flute end mills with a TiCN (titanium carbonitride) coating. This type of tool provides excellent chip evacuation, which is key to avoiding clogging.

• Ensure a constant, abundant flow of coolant (cutting fluid). This not only lubricates and cools the cutting zone but also helps flush chips out of cavities, preventing them from sticking to the tool or the part.

• Do not underestimate workholding. Although aluminum is a soft material, high machining speeds generate considerable forces. Use reliable clamping systems to avoid vibrations that could affect the precision and finish of the part.

Advantages of CNC machining of aluminum

When the properties of aluminum are combined with the precision of numerical control, the result is a manufacturing process with direct benefits for any workshop. CNC technology not only automates production but also takes quality and design possibilities to a new level.

The most notable advantages are:

• High precision and repeatability: CNC executes the instructions of a digital program with extraordinary precision, achieving tolerances of up to ±0.01 mm. More importantly, it can replicate this precision across thousands of identical parts, ensuring consistent quality and eliminating human operator variability.

• Producing complex geometries: Software control makes it possible to create designs with a geometric complexity that would be impossible or prohibitively expensive to achieve with manual methods. From curved surfaces to internal cavities, CNC opens the door to innovation in the design of lighter, stronger components.

• Improved efficiency and productivity: CNC machines are designed to operate continuously with minimal human intervention, maximizing productive time. The ability of machining centers Vurcon, such as those in the VL series, to perform multiple operations in a single setup dramatically reduces cycle times.

Vurcon performance data: To give you an idea of real-world performance, our vertical machining centers reach spindle speeds of up to 10,000 RPM. This enables material removal rates in alloys such as 6061 aluminum 70% higher than those of conventional equipment from a decade ago, transforming your workshop's production capacity.

Simplified success story: A customer in the mold sector cut the machining time of an aluminum plate from 45 to just 18 minutes after installing a Vurcon VL-85 machining center. This allowed them to accept 30% more orders per month, paying off the investment in less than 22 months.

Cost optimization for short runs and prototypes: Unlike other methods that require expensive molds, CNC machining of aluminum is highly flexible. It allows anything from a single prototype to medium production runs to be produced cost-effectively.

Types of parts machined in aluminum

The versatility of CNC-machined aluminum has made it a cornerstone of the most innovative and demanding industries. The ability to produce light, strong and precise components applies to countless products.

Some of the most relevant sectors and applications include:

• Aerospace sector: This is the field par excellence for high-strength aluminum. CNC is used to manufacture critical structural components such as wing ribs, bulkheads and engine mounts, where weight reduction is crucial.

• Automotive industry: To improve efficiency, manufacturers use aluminum in engine components, chassis and suspension parts. High thermal conductivity is vital for dissipating heat, and low weight improves vehicle dynamics.

• Consumer electronics: The housings of products such as laptops and smartphones are machined from a single block of aluminum (“unibody”). This process provides premium aesthetics and robustness, ensuring a perfect fit for the internal components.

• Medical sector: The medical industry relies on CNC to manufacture everything from surgical instruments and orthopedic devices to implants. The ability to produce complex shapes with smooth finishes is essential for patient safety.

Most common processes in CNC machining of aluminum

To shape aluminum, CNC machinery uses different subtractive operations. Each is designed to achieve specific geometries, and they are often combined on the same part. The fundamental processes are:

1. CNC milling: A rotating tool (milling cutter) removes material from a stationary workpiece. It is the ideal process for creating flat surfaces, cavities and complex contours. The vertical machining centers, such as those in our Vurcon VL series, are the milling machines par excellence.

2. CNC turning: The workpiece rotates at high speed while a cutting tool moves to shape it. It is perfect for creating axially symmetrical components such as shafts and pins. The CNC lathes, such as those in our Vurcon PL series, are the specific solution for these applications.

3. CNC drilling: It is used to create holes in a part using a rotating drill. CNC also allows high-precision secondary operations such as reaming (to improve the finish) and threading (to create internal threads).

Vurcon's commitment: beyond the machine

At Vurcon we understand that a machine is a long-term strategic investment. That is why our commitment goes beyond the sale. All our machines come with a technical service team based locally, an initial training plan for your operators and a guaranteed availability of critical spare parts in less than 48h. Our goal is clear: to make sure your production never stops and that your investment pays off from day one.

Ready to take your aluminum production to the next level? Contact our team of specialists to receive personalized advice and discover how our CNC solutions can optimize your workshop.