Aluminum extrusion is a versatile and cost-effective manufacturing process that transforms aluminum alloys into precisely shaped profiles used across various industries. This method enables manufacturers to produce lightweight, durable, and complex aluminum components efficiently. Whether applied in construction, automotive, aerospace, or industrial applications, extruded aluminum provides an ideal balance of strength, flexibility, and corrosion resistance.

In this comprehensive guide, we explore the aluminum extrusion process in detail, the different types of extrusions, their wide-ranging applications, and how to select the best supplier for your needs.

What is Aluminum Extrusion?

Aluminum extrusion is a technique where aluminum alloy material is forced through a die to create a cross-sectional profile. This process enables the production of continuous lengths of aluminum with uniform dimensions, making it ideal for large-scale manufacturing. The method can create simple shapes like rods and bars, as well as intricate profiles with complex geometries.

Key Advantages of Aluminum Extrusion:

• High strength-to-weight ratio – Aluminum extrusions maintain structural integrity while remaining lightweight, making them ideal for aerospace and automotive applications where weight reduction is crucial.
• Corrosion resistance – Aluminum naturally forms an oxide layer that protects it from rust and degradation, making it perfect for outdoor and marine applications.
• Excellent thermal and electrical conductivity – Aluminum is widely used in heat sinks and electrical enclosures due to its ability to efficiently dissipate heat and conduct electricity.
• Ease of fabrication – Extruded aluminum can be easily cut, drilled, machined, welded, or bonded, providing great flexibility for engineers and designers.
• Sustainability and recyclability – Aluminum is 100% recyclable without losing its quality, making it an environmentally friendly material choice.

The Aluminum Extrusion Process in 10 Steps

Aluminum extrusion is a complex yet highly efficient process that transforms solid aluminum billets into continuous profiles with consistent cross-sections. Below is a detailed breakdown of the process in ten key steps:

Step 1: Die Preparation

Every extrusion begins with the die—a precision-engineered tool that defines the final profile. A round-shaped die, typically made of H13 steel, is either freshly machined or retrieved from storage. It is preheated to 450–500°C (840–930°F) to ensure optimal metal flow and prolong die life. Once heated, the die is installed into the extrusion press.

Step 2: Billet Preheating

An aluminum billet—a solid cylindrical log cut from an aluminum alloy log (usually 6000 series)—is preheated in a furnace to 400–500°C (750–930°F). This temperature softens the metal without melting it, making it malleable enough for extrusion.

Step 3: Billet Transfer and Lubrication

The preheated billet is mechanically transferred to the extrusion press. Prior to insertion, a release agent or lubricant is applied to both the billet and the ram to prevent sticking during high-pressure extrusion.

Step 4: Billet Insertion and Pressurization

The billet is loaded into the container of the extrusion press. A hydraulic ram applies immense pressure (up to 15,000 tons) to force the billet material through the die. Inside the container, the billet deforms plastically and fills the container walls completely.

Step 5: Profile Emerges from the Die

Under continuous pressure, the aluminum material is forced through the die’s opening. The result is an elongated profile that matches the die’s cross-section. This newly formed extrusion begins its journey down the runout table.

Step 6: Quenching on the Runout Table

As the hot extrusion exits the die, it is immediately gripped by a puller and guided along a runout table. During this motion, the profile is quenched using water sprays or air jets to rapidly cool and stabilize the aluminum’s microstructure.

Step 7: Shearing to Table Length

When the extrusion reaches the desired length, a hot saw shears it off from the continuous piece. Although quenched, the profile remains hot and must cool further before handling.

Step 8: Cooling to Room Temperature

The cut profiles are transferred to a cooling table, where they remain until they reach ambient temperature. This step ensures dimensional stability before further mechanical processing.

Step 9: Stretching for Alignment

Natural twisting or warping may occur during extrusion. To correct this, each profile is clamped at both ends and mechanically stretched to restore its straightness and meet specified tolerances.

Step 10: Final Cutting and Optional Aging

The straightened extrusions are moved to a finish saw, where they are cut to final lengths—typically between 8 and 21 feet. At this stage, the extrusions are at T4 temper. Depending on strength requirements, they may undergo aging heat treatments to achieve T5 (artificial aging) or T6 (solution heat treated and aged) tempers.

Types of Aluminum Extrusions

The versatility of aluminum extrusion allows for a wide range of profile types:

A. Stock Aluminum Extrusions

Pre-manufactured standard profiles, including:

• Channels
• Angles
• Tubes
• Bars

B. Extruded Aluminum Shapes

• Solid profiles: Rods, bars, and angles for structural applications.
• Hollow profiles: Tubes and rectangular sections for lightweight frameworks.
• Semi-hollow profiles: Designed for intricate structural needs.

C. Custom Aluminum Extrusions

Tailored for industries like automotive, aerospace, and electronics to optimize material use and enhance structural efficiency.

D. Telescoping Aluminum Extrusions

Designed for adjustable applications such as:

• Extendable poles
• Tripods
• Adjustable frames

E. Extruded Aluminum Frames

Widely used in:

• Architectural structures (windows, doors)
• Solar panel mounting systems
• Industrial machine enclosures

F. T-Slot Aluminum Extrusions

Modular profiles used in:

• Industrial workstations
• Automation equipment
• Machine guards and enclosures

Post-Extrusion Processing: Heat Treatment, Finishing, and Fabrication

After the aluminum extrusion process is complete and the profiles are cut to length, they often undergo additional processing steps to improve mechanical properties, appearance, and application suitability.

Heat Treatment (Aging)

Depending on the desired strength, extrusions can be artificially aged in ovens to achieve specific tempers:

• T5 Temper: The profile is cooled after extrusion and then artificially aged to increase hardness.

• T6 Temper: Involves solution heat treatment followed by artificial aging, providing the highest strength for many applications, including structural components in aerospace and automotive.

Surface Finishing

Surface treatment enhances durability, corrosion resistance, and visual appeal:

• Anodizing: Forms a durable oxide layer that can be dyed in various colors while increasing corrosion resistance.

• Powder Coating: Adds a tough, uniform finish available in a broad range of colors and textures.

• Mechanical Finishing: Techniques like polishing, brushing, or bead-blasting are used for aesthetic enhancement or to prepare the surface for further treatment.

Fabrication and Secondary Machining

Extruded profiles are often fabricated into final components through:

• CNC Machining: For drilling, tapping, milling, or slotting complex features.

• Welding and Assembly: Extrusions can be joined via TIG/MIG welding or bolted together in modular systems.

• Cutting and Bending: Depending on the alloy and profile, aluminum extrusions can be cut to precise dimensions or bent into functional shapes.

These post-extrusion processes add value and allow aluminum extrusions to meet exact performance requirements in high-end applications.

6 Factors Affect the Quality of Extruded Aluminum

Several variables influence the quality, strength, and surface finish of extruded aluminum profiles. Understanding these factors helps ensure consistent and reliable results:

1. Alloy Selection

Different alloys (e.g., 6061, 6063, 7075) have unique mechanical, thermal, and corrosion-resistant properties. Choosing the right alloy for the end-use application is critical.

2. Die Design and Condition

Precision in die manufacturing directly impacts the dimensional accuracy and surface quality of the extrusion. Worn or poorly maintained dies can lead to defects like tearing, warping, or uneven flow.

3. Extrusion Temperature and Speed

Maintaining the correct billet temperature and controlling the ram speed during extrusion affects metal flow, mechanical properties, and internal stress levels. Overheating or rushing the process can cause defects such as surface cracks or inconsistent dimensions.

4. Cooling and Quenching Techniques

Uniform and controlled cooling prevents distortion and enhances the strength of the extruded profile. Inconsistent quenching can cause warping, residual stress, or hardness variations.

5. Stretching and Alignment

Proper alignment through stretching ensures dimensional accuracy and eliminates natural bowing or twisting that may occur during extrusion and cooling.

6. Post-Processing

Finishing methods such as heat treatment and anodizing affect final performance. Inadequate heat treatment can lead to poor mechanical properties, while improper anodizing may reduce corrosion resistance.

Applications of Aluminum Extrusions

Aluminum extrusions are widely used due to their strength, durability, and lightweight properties:

• Automotive – Reduces vehicle weight, improving fuel efficiency.
• Construction – Essential for windows, doors, facades, and roofing structures.
• Electronics – Used in heat sinks to dissipate heat efficiently.
• Aerospace – Provides structural integrity while keeping aircraft lightweight.
• Furniture & Interior Design – Creates stylish and functional furniture designs.

Advantages and Disadvantages of Aluminum Extrusion

Advantages:

• Lightweight with High Strength: Ideal for applications where weight reduction is critical without compromising structural integrity.

• Corrosion Resistant: Naturally forms a protective oxide layer, perfect for outdoor and marine use.

• Design Flexibility: Allows for the creation of complex, hollow, or solid cross-sections tailored to specific needs.

• Excellent Thermal Conductivity: Widely used in electronics for heat dissipation.

• Recyclable and Sustainable: Aluminum can be recycled repeatedly without degradation in quality.

• Cost-Effective for High Volumes: Once dies are made, per-unit production is efficient and economical.

Disadvantages:

• Initial Tooling Cost: Custom die creation can be expensive for low-volume orders.

• Material Limitations: Not suitable for applications requiring extremely high strength or hardness (e.g., compared to steel).

• Dimensional Tolerances: While precise, extrusion has limits on tolerances for extremely fine features.

• Surface Defects: Improper processing may lead to surface marks or internal voids.

• Thermal Sensitivity: Extruded aluminum may deform under high operating temperatures unless properly treated.

Why is it Called 80/20 Aluminum Extrusion?

The term “80/20 aluminum extrusion” refers to a popular modular T-slot framing system originally developed by the company 80/20 Inc. It is widely used in industrial, manufacturing, and DIY environments due to its versatility.

The name comes from a specific profile size—80mm x 20mm—but has become a generic term to describe T-slot aluminum extrusions used for:

• Framing

• Machine enclosures

• Workstations

• Robotic platforms

• Conveyor systems

It operates on the principle of modular design, allowing parts to be easily connected, adjusted, or reconfigured without welding or complex tools, much like an adult-sized “Erector Set.”

What is the Difference Between 4040 and 8020 Aluminum Extrusion?

Both 4040 and 8020 are types of T-slot aluminum extrusions, but they differ primarily in dimensions, load capacity, and configuration:

Conclusion:

• Use 4040 when you need balanced strength and rigidity in all directions.

• Use 8020 for space-saving, modular structures with lower load requirements.

How to Choose the Right Aluminum Extrusion Supplier

Selecting the right aluminum extrusion supplier is crucial for ensuring product quality, cost efficiency, and timely delivery. Here are key factors to consider when evaluating potential suppliers:

​1. Reliable Aluminum Extrusion Company

• ​Reputation & Experience: Look for suppliers with a proven track record in the industry. Check customer reviews, case studies, and industry references.
• ​Manufacturing Facilities: Ensure the supplier has modern, well-maintained extrusion presses, CNC machining centers, and finishing capabilities.
• ​Technical Expertise: The supplier should have engineers who can assist with design optimization, material selection, and prototyping.

​2. Quality Standards (ISO, ASTM Certification)

• ​ISO 9001 Certification: Ensures the supplier follows standardized quality management processes.
• ​ASTM Compliance: Confirms that the aluminum extrusions meet industry-specific mechanical and chemical property standards.
• ​In-House Testing: The supplier should conduct dimensional checks, tensile strength tests, and surface finish inspections.
• ​Third-Party Audits: Some industries (e.g., aerospace, automotive) may require NADCAP or IATF 16949 certifications.

​3. Customization Capabilities

• ​Design Support: Can the supplier assist with CAD modeling, DFM (Design for Manufacturing) analysis, and prototyping?
• ​Material Options: Availability of different alloys (e.g., 6061, 6063, 7075) and tempers (T5, T6).
• ​Secondary Operations:
  • CNC Machining
  • Drilling, Tapping, Milling
  • Anodizing, Powder Coating, Brushing
  • Heat Treatment & Welding
• ​Tolerance Precision: Ensure the supplier can meet tight tolerances (±0.005″ or better if required).

​4. Production Lead Times

• ​Standard vs. Expedited Lead Times: Some suppliers offer rush production for urgent orders.
• ​Inventory Management: Does the supplier keep raw material stock to reduce lead times?
• ​Production Capacity: Can they handle large-volume orders without delays?
• ​Supply Chain Transparency: Real-time order tracking and communication on potential delays.

​5. Competitive Pricing & Logistics Reliability

• ​Cost Breakdown: Compare material costs, tooling fees, machining charges, and finishing costs.
• ​MOQ (Minimum Order Quantity): Some suppliers offer low MOQs for prototypes or small batches.
• ​Shipping & Logistics:
  • Domestic vs. Overseas Suppliers: Weigh cost savings against longer lead times and import duties.
  • Packaging Standards: Proper packaging to prevent damage during transit.
  • Freight Options: Air, sea, or land shipping with reliable carriers.
• ​Payment Terms: Flexible options (e.g., Net 30, LC, or milestone-based payments).

​Additional Considerations:

• ​Sustainability Practices: Does the supplier use recycled aluminum or eco-friendly processes?
• ​After-Sales Support: Warranty policies, return procedures, and technical assistance.
• ​Long-Term Partnership Potential: A supplier willing to grow with your business can offer better pricing and priority support.

By thoroughly evaluating these factors, you can choose an aluminum extrusion supplier that aligns with your project requirements, budget, and timeline.

Frequently Asked Questions

What is the raw material for aluminum extrusion?.

Extrusion primarily uses 6000 series aluminum alloys, known for strength, machinability, and corrosion resistance

What is the most common aluminum extrusion?

The term “8020” refers to 80/20 T-slot framing, a modular aluminum system used in industrial and DIY applications.

Conclusion

Aluminum extrusion is a vital manufacturing process offering unparalleled flexibility, durability, and sustainability. Whether using stock extrusions or designing custom aluminum profiles, partnering with the right supplier ensures optimal performance and efficiency.

If you would like to learn more about how to optimize your part design for the extrusion process, please upload your drawing to contact our professional and experienced engineers. At CSMFG, we provide first-class aluminum extrusion services to help you with prototyping and mass production. Contact us today to discuss your project and see how we can deliver high-quality results.