Madeline Hogan
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The CNC machining market is growing at an unprecedented rate, with the global market projected to reach a value of USD 129.9 billion by 2027, growing at a steady CAGR (Compound Annual Growth Rate) of 6.8%. Why? CNC machining offers unparalleled efficiency and precision–making it a preferred manufacturing method for various industries, from aerospace to electronics to automotive. 

Aluminum is commonly used in CNC machining due to its lightweight properties, strength, and resistance to corrosion. Whether you require complex components or high-volume production runs, aluminum CNC machining ensures consistent quality and reliable performance.

In this guide, we explore the basics of aluminum CNC machining, its processes, uses, and advantages.

What is Aluminum Machining? 

Aluminum machining is a manufacturing process that involves removing material from a block of aluminum to create specific shapes and components, such as engine blocks, cylinder heads, and suspension components. It’s a versatile technique used in various industries due to aluminum’s lightweight, corrosion resistance, and excellent machinability.

There are different methods of aluminum machining, but the most advanced and popular is CNC (Computer Numerical Control) machining. 

What is CNC Machining?

CNC machining is a precise, subtractive process that begins with programming a combination of CNC tools to build a part directly from a CAD file. The machines etch out the design from a solid block of metal or other material to reveal the part shape. For larger or more complex parts, the parts will be created in sections, and the sections will be bonded back together to form a highly accurate part with a higher-quality surface that’s ready for plating, painting, or polishing.

CNC machining uses pre-computerized software and codes to dictate cutting instructions to factory tools. These codes tell the CNC machines what exact movement paths to follow when cutting a piece of material, such as metal or plastic, without a manual operator. By eliminating the need for a manual operator, CNC machining significantly increases the precision and accuracy attainable during production processes. 

CNC machining languages G-codes and M-codes replace the need for manual input by instructing the machine on how to perform specific tasks during the cutting process. G-codes are responsible for the machine’s movements, while M-codes control auxiliary functions like starting or stopping the machine.

Typical Machined Aluminum Parts

Aluminum CNC machining is particularly valuable in sectors like aerospace manufacturing, where it creates lightweight, high-strength components such as aircraft fuselage and engine components. In the automotive industry, it’s employed to manufacture engine blocks, transmission cases, and other critical parts that benefit from aluminum’s strength-to-weight ratio.

Let’s take a look at some of the typical machined aluminum parts:

  • Aerospace: Aluminum’s high strength-to-weight ratio makes it ideal for aircraft components like structural brackets, body panels, and landing gear
  • Automotive: Aluminum machining produces key vehicle parts, including chassis frameworks, engine blocks, and suspension components
  • Electronics: Precision-machined aluminum is used in computer casings, smartphone frames, and heat sinks for efficient thermal management
  • Construction: Aluminum parts such as window frames, door frames, and siding are valued for their durability and corrosion resistance
  • Consumer goods: Machined aluminum is used in appliance housings, furniture, and sporting goods due to its lightweight and durability

Overview of Aluminum Machining Processes

Let’s take a look at some of the aluminum machining processes:

Milling

Milling is the process of removing material from an aluminum workpiece using a cutting tool. involves using rotary cutters to cut down metal material by advancing a cutter into the workpiece to remove chips. In this case, “workpiece” is a term used to describe the block of aluminum being processed into another shape, and ‘chips’ are the fragments removed from the workpiece during the cutting process. 

The workpiece is mounted rigidly on a table, and this table moves or rotates at a varying pace, ensuring the cutter can cut the workpiece at any angle. 

Turning 

CNC turning is an automated machining process that removes material from a cylindrical workpiece. During this process, the workpiece is held in a chuck and rotated while a tool is fed to it to remove material accurately. This process of cutting away material while the workpiece spins at high speed helps to create complex and intricate geometries accurately. 

Although CNC turning is typically used to work on cylindrical workpieces, it can also work on materials in other shapes. 

Drilling

CNC drilling uses a rotating cutting tool to create holes in a stationary workpiece. This process can be compared to manual drilling. However, unlike manual drilling, CNC drilling is fully automated, ensuring high accuracy and consistency that cannot be achieved using traditional production methods. CNC drilling can be used to create precise holes to fasten components together and can also be used to create complex parts with tight tolerances. 

How Aluminum CNC Machining Works

Let’s take a look at how aluminum CNC machining works:

1. Design & Create a CAD File

The aluminum machining process begins with creating a computer-aided design file, which serves as the blueprint for the aluminum part to be produced. This step is important in industries such as automotive manufacturing, where precision and material specifications matter. 

After finalizing the design specifications, the manufacturer uses CAD software to develop a 3-dimensional model of the part. This model is saved as a CAD file and contains essential information for the manufacturing process, including dimensions and material specifications.

2. Choose Aluminum Grade

Selecting the right aluminum grade is important in CNC machining, as each alloy has unique properties that affect machinability. 

Let’s look at some of the common classes of aluminum alloy and their features.

  • Aluminum (6061-RAM2): It has a high strength-to-weight ratio, good corrosion resistance, weldability, good thermal conductivity, and is used in medical devices for its biocompatibility.
  • Aluminum (AlSi10Mg): This alloy has a high strength-to-weight ratio, making it ideal for strong, lightweight parts with corrosion resistance. It is commonly used in aerospace, automotive, and industrial manufacturing applications, particularly for complex geometries with intricate features.
  • Aluminum (AlSi12): It has a high strength-to-weight ratio and thermal and electrical conductivity. It is commonly used in pump and valve components, electrical connectors, and wheel transmission cases.
  • Grade 6061: A versatile, medium to high-strength, heat-treatable alloy with good weldability, corrosion resistance, and formability. It’s the most common alloy used in machining.
  • Grade 2011: Known as the free machining alloy (FMA), 2011 offers exceptional machinability, making it ideal for automatic lathes. However, it has poor weldability and corrodes easily if not anodized.
  • Grade 2024: This aluminum alloy has copper as its primary alloying element. It has impressive strength and fatigue resistance, making it especially useful in applications that require a high strength-to-weight ratio.
  • Grade 5052: An aluminum-magnesium alloy with high fatigue strength, good formability, and excellent corrosion resistance, particularly valuable in marine applications 
  • Grade 6063: A medium-strength, heat-treatable alloy with magnesium and silicon, commonly used in intricate extrusion processes 
  • Grade 7075: Often called “aircraft-grade” due to its high strength, this zinc-alloyed aluminum is heat-treatable with moderate formability and excellent mechanical properties

3. The Machining Process

After selecting your aluminum material and finalizing the CAD design, the next step is to begin the machining process. This involves making key decisions about tool selection, helix angles, and cutting speeds.

  • Tool design: Your choice of tools in aluminum processing can make or break your production process. Although different aspects of tool geometry affect aluminum production, the tool’s flute count is one integral factor to consider. Ideally, cutting tools for CNC aluminum machining should have two or three flutes. 2-flute tools are better for plunging while 3-flute tools offer a balance between chip clearance and strength. 
  • Helix angle: This term describes the angle between the center line of a tool and a straight line tangent along the cutting edge. Although a high helix angle removes chips from a workpiece faster, it increases friction and heat during the cutting process. This may cause the chips to stick to the tool surface during high-speed machining. A lower helix angle produces less heat but is less efficient at removing chips. 
  • Cutting speed: Aluminum requires high cutting speeds, but excessive speed can cause overheating and melting. Different aluminum alloys have specific cutting speed requirements. 

Once these factors are determined, the CAD file is translated into CNC codes (G-codes) and uploaded to the CNC machine. The machine then executes the machining process, cutting the aluminum according to the programmed instructions using the selected tools and parameters.

4. Post Processing in CNC machining

After machining, aluminum parts undergo post-processing to enhance the aesthetic and functional features. Let’s take a look at the various post processing techniques:

  • Bead and sand blasting: This technique smooths the surface of the machined aluminum part by blasting it with tiny glass beads using a high-pressure air gun
  • Coating: Aluminum parts are coated with materials like zinc or chrome to improve their durability and resistance to corrosion
  • Anodizing: An electrochemical process that converts the surface of the aluminum part into a hard, non-reactive aluminum oxide coating, enhancing its strength and corrosion resistance
  • Powder coating: This process involves applying colored polymer powders to the aluminum part using an electrostatic spray gun, providing a durable, corrosion-resistant, and wear-resistant finish

The aluminum machining process involves multiple complex steps, from initial design to final post-processing. These steps can be challenging and costly, particularly for small businesses.

However, partnering with specialized companies like UPTIVE Advanced Manufacturing can help streamline production. UPTIVE is a leader in the rapid manufacturing industry, offering advanced digital solutions, including injection molding & tooling,  sheet metal fabrication, rapid prototyping, and additive manufacturing. 

UPTIVE’s CNC machining solutions provide speed and material versatility, transitioning your design from prototyping to production. The team supports low-, medium-, and large-volume production with quick turnaround times for prototypes, short runs, and pre-production trials. Their materials and systems improve joining characteristics, hardness uniformity, and surface quality for more available finishing options.

Explore UPTIVE’s CNC machining capabilities. 

Challenges in Aluminum Machining

While aluminum machining addresses many efficiency issues that traditional manufacturing processes face, it also presents several challenges that can complicate the process. 

Let’s take a look at some of these challenges:

  • Chip formation: Although aluminum is generally soft and ductile, some alloys have high viscosity, leading to long chips that can wrap around the cutting tool, potentially causing part breakage. Managing this requires careful attention to the tool’s flute size.
  • High costs: Aluminum machining demands specialized tools, which can be expensive to invest in
  • Thermal buildup: Aluminum’s excellent heat conductivity can cause significant thermal buildup during machining, leading to melting, tool fusion, or warping of the part being formed
  • Chatter: High cutting speeds in aluminum machining can cause rattling or “chatter,” making it difficult to achieve precise results
  • Warping: Due to its softness, aluminum is prone to warping, which can hinder the precise and accurate production of parts
  • Design mistakes: Design mistakes such as ignoring tolerances and material constraints, designing complex geometries without necessity, incorporating inadequate filets and sharp corners, and poorly planning tool paths can further complicate the machining process, leading to inefficiencies and compromised part quality

Working with experts like UPTIVE Advanced Manufacturing can help overcome these challenges. UPTIVE’s experienced team provides the expertise to mitigate the difficulties associated with aluminum machining, enabling businesses to produce aluminum parts quickly and efficiently.

Get started with UPTIVE

Advantages of Using an Aluminum Machining Service

Let’s take a look at the advantages of using an aluminum machining service:

Improved Precision 

Aluminum machining services utilize advanced CNC technology, state-of-the-art equipment, and expert operators to achieve precise measurements, tight tolerances, and minimal defects. This combination of technology and expertise is important for producing high-quality aluminum parts, including producing more complex parts with a variety of materials: aluminum, stainless steel, titanium, Invar, Kovar, brass, and plastics. 

Faster Iterations

These services often have access to a wide range of specialized equipment and resources, enabling faster turnaround times and efficient workflows. Their expertise allows for quick design iterations, prototype testing, and post-processing, ensuring the rapid production of aluminum parts without compromising quality. This efficiency is important for accelerating precision and timelines for tooling, progressive dies, and assembly fixtures in higher quantities.

Design Flexibility 

With access to cutting-edge technology and a deep understanding of aluminum machining, these services offer businesses the freedom to explore complex geometries and unconventional designs that traditional methods can’t achieve. This flexibility allows companies to take designs to production faster, including prototypes with complex geometries via CNC prototyping.

Various Post-processing Options

Aluminum machining services provide various post-processing solutions due to their investment in the latest technology and equipment. This includes options like sandblasting, anodizing, and more—all tailored to improve the appearance and functionality of your parts, creating metal and non-metal surfaces with better acceptance of coatings and a variety of paint finishes.

FAQs on Aluminum Machining

Understanding the common questions surrounding aluminum machining can help you make more informed decisions about the process. 

What types of aluminum are used in CNC machining? 

Different types of aluminum alloys can be used in CNC machining, each offering various properties suitable for different applications. Some common aluminum alloys used include grades 6061, 2011, and 2024. 

What other materials can you use in CNC machining?

CNC machining isn’t limited to aluminum; it can also be used with materials like stainless steel, brass, titanium, steel, and copper. Additionally, CNC machining can create plastic components from materials such as PEEK, polycarbonate, and nylon through a process known as plastic CNC manufacturing.

Access the Best Aluminum Machining Service

Aluminum machining, powered by CNC technology, offers efficiencies and precision that traditional methods can’t match. To fully leverage these benefits, it is important to partner with a reputable and experienced service provider.

UPTIVE offers a range of CNC machining solutions suitable for various materials such as plastic and aluminum. These solutions provide greater speed and material versatility, enabling your design to move seamlessly from prototyping to production. Their team works closely with you to support low-, medium-, and large-volume production, ensuring quick turnaround times for prototypes, short runs, and pre-production trials. UPTIVE’s capabilities include CNC milling, CNC turning, and CNC   prototyping, allowing you to produce large, complex prototypes directly from your CAD files. 

UPTIVE focuses on the most important aspect of the product development process—personal service. The company provides customers with personalized support and guidance throughout the design and production process enabling the customer to get the best service imaginable. 

With their advanced technologies and experienced team, UPTIVE is well-equipped to support your journey into the future of manufacturing.

Explore UPTIVE’s CNC machining solutions here.