Understanding the Aluminum Extrusion Process

From the sleek window frames of modern skyscrapers to the lightweight chassis of an electric vehicle, aluminum plays a role in countless everyday structures and products. Its strength, light weight, corrosion resistance, and recyclability make it one of the most versatile materials in modern manufacturing. The process that turns solid billets into these functional profiles is aluminum extrusion.

This article explains how the aluminum extrusion process works step by step, showing how a billet of aluminum is transformed into the critical components used across architecture, industry, and transportation.

What Is Aluminum Extrusion?

Aluminum extrusion is a manufacturing process in which a preheated aluminum billet is forced through a die under high pressure. The metal takes on the die’s shape, producing profiles with a consistent cross-section.

The process can be compared to squeezing toothpaste from a tube: just as the paste emerges in the shape of the opening, aluminum comes out in the shape of the die.

This technique is highly versatile, enabling the production of everything from simple rods to complex hollow profiles and custom structural components in a single pass. Because of this flexibility, extrusion is widely used in construction, transportation, electronics, aerospace, and machinery.

When combined with additional steps such as heat treatment and surface finishing, extrusion can further improve the mechanical strength, durability, and appearance of aluminum products, making it an efficient and adaptable manufacturing method.

Pre-Processing: Design & Material Selection

Every extrusion project begins with two essential steps: defining the profile shape and **choosing the right aluminum alloy**. These decisions determine not only how the extrusion will be carried out but also the final product’s performance and appearance.

• Profile Design & Die Design

  Extrusion allows profiles to be made in many different shapes. Some follow standard designs, while others are customized for special functions. Depending on the application requirements, these designs can generally be grouped into two main types:

   - Standard Profiles

  This category includes common shapes such as L-shaped angles, square tubes, round tubes, and the T-slot profiles frequently used in industrial applications. Because these profiles are created using existing (standard) dies, they offer the benefits of lower tooling costs and shorter development times. This makes them an ideal solution for general-purpose, high-volume, and versatile application needs.

   - Custom Profiles/Shapes

  When products require special functional features, such as snap-fit joints, sliding tracks, heat-dissipating fins, fastening connectors, or decorative designs, dedicated profile designs and new dies must be developed. These custom extrusions often involve complex geometries, uneven wall thicknesses, or even large openings, which make them more prone to deformation, warping, or stress concentration during manufacturing. As a result, their design and production present greater challenges.

• Material Selection

  The main material used in aluminum extrusion is the aluminum alloy billet. These billets are preheated before entering the press, and different alloy series are chosen based on the needs of the final product.

  Commonly used alloy series include:

  • 6000 series – Known for excellent extrudability and corrosion resistance. Widely used in construction, automotive frames, and general structural applications.
  • 7000 series – Offers very high strength and is often selected for aerospace, defense, and high-performance sporting equipment.
  • 2000 series – Provides solid mechanical properties and good machinability, making it suitable for aerospace and industrial machinery components.

  When selecting the material, it is also important to specify billet diameter, length, and purity grade to ensure uniform heating and stable extrusion throughout the process.

Main Aluminum Extrusion Process

• Die Preheating

  The extrusion process kicks off with preheating the die to approximately 450–500°C. Once at the target temperature, it is mounted onto the bolster of the extrusion press. This step ensures a smooth and uniform metal flow, extends the die’s service life, and reduces the likelihood of defects in the final product.

• Billet Preheating

  Aluminum billets must be heated in a furnace to around 400–500°C to achieve optimal plasticity. Once preheated, the billets are transferred into the container of the extrusion press, either through an automated system or manual handling, where they are prepared for high-pressure extrusion.

• Extrusion Through the Die

  Once heated, the aluminum billet is pressed by the ram of the hydraulic system with high pressure, forcing it through the preheated die. During this process, the aluminum is shaped into the designed cross-sectional profile and extruded either continuously or intermittently, depending on production requirements.

• Cooling and Quenching

  The freshly extruded aluminum profiles are still at a very high temperature and must be rapidly cooled using either water spray or air fans. This rapid cooling process, known as quenching, helps stabilize the material’s properties for further processing.

• Stretching and Cutting

  After cooling, the extruded aluminum profiles may be slightly twisted due to thermal stress. At this stage, a **stretcher** is used to pull both ends of the profile to straighten it, correcting any dimensional or shape deviations.

Post-Processing: Strengthening and Finishing

• Heat Treatment

  After extrusion, aluminum profiles are usually subjected to artificial aging to enhance their strength and hardness. This process is known as heat treatment, with common methods including T5 and T6. T5 refers to aging immediately after quenching, while T6 involves solution heat treatment followed by aging. By carefully controlling time and temperature, the mechanical properties of aluminum alloys can be optimized to meet the structural requirements of different applications.

• Surface Finishing

  Surface finishing for aluminum profiles effectively improves a product's corrosion resistance, aesthetic quality, and functionality. Common treatment methods include anodizing, powder coating, and polishing. These processes not only protect the base material but also provide a variety of colors, gloss levels, and textures.

• Secondary Machining

  Depending on the intended application, extruded aluminum profiles may require additional machining processes. These include drilling, tapping, milling, or other finishing operations to meet installation, tolerance, or functional requirements. The precision and consistency of secondary machining play a critical role in ensuring proper assembly and overall product performance.

Why Choose Grand Latitude’s Aluminum Extrusion Service?

In the aluminum extrusion process, the precision of die design and the production capability of the equipment are key factors that determine whether a product can achieve the desired structural strength and functional integration. Grand Latitude has extensive expertise in designing custom profiles and developing dies, enabling us to create special cross-sections tailored to customer needs. We are experienced in handling asymmetric structures, uneven wall thicknesses, and multifunctional integrated designs, helping clients achieve product innovation and engineering optimization.

In addition, we are equipped with high-spec production facilities, including a 14-ton extrusion press that enables stable manufacturing of large aluminum profiles designed for high-load and long-span applications. For example, we successfully assisted in the development of oversized aluminum alloy structural components for fire ladder trucks, which required exceptionally demanding size and strength specifications. This highlights our technical expertise and manufacturing experience in handling large-profile aluminum extrusion projects.

From design and die development to aluminum extrusion, heat treatment, surface finishing, and secondary machining, we provide one-stop integrated services tailored to customer needs. This approach greatly streamlines the development process while ensuring consistent quality. Whether you are still in the early concept stage or already have a finalized design, we welcome you to contact us. Let Grand Latitude be your trusted partner for aluminum extrusion solutions.