Aluminum Extrusion Process: An Analytical Overview

Aluminum has positioned itself as a globally accepted material in various industries due to its unique set of characteristics. Among the many methods used to manipulate this versatile material, the Aluminum Extrusion Process stands out due to its flexibility and efficiency. This procedure has seen an escalating trend in usage across a multitude of sectors, from the architectural industry to the aerospace field, largely due to its ability to produce a vast array of complex profiles.

At Worthy Hardware, we strive to offer unparalleled expertise in aluminum extrusion and various other manufacturing processes. As a leading CNC machining service provider, we ensure the delivery of top-quality machined products that cater to the unique requirements of our diverse clientele.

The Concept of Aluminum Extrusion


What is casting process?

To grasp the concept of the Aluminum Extrusion Process, it is necessary to clarify a few terminologies. Primarily, ‘extrusion’ refers to the method of shaping material by forcing it to flow through a shaped opening in a die. The resulting product – an elongated piece with a profile matching the die – is known as an ‘extrudate’.

For a simplified comprehension of the process, imagine squeezing toothpaste from a tube. The paste (material) is forced through the opening (die), and it takes the shape of the opening as it comes out. Now, replace the toothpaste with a solid aluminum billet and the toothpaste cap opening with a specifically designed die, and you have the basic idea of the Aluminum Extrusion Process.

Historical Background of Aluminum Extrusion

The extrusion process traces its roots back to the early 18th century when blacksmiths first began forging metals through dies to produce an array of items. However, the advent of the hydraulic press in the 19th century marked a significant milestone for the extrusion process, as it laid the foundation for thermal extrusion.

In this process, the material is heated before being pushed through the die, significantly lowering the force required for extrusion and enabling the production of more complex and intricate shapes. As more and more materials started being extruded, the spotlight inevitably fell on aluminum.

Aluminum emerged as an ideal material for extrusion in the early 20th century, thanks to its exceptional malleability and lightness combined with high durability. The escalation of aluminum extrusion usage during this time heralded the advent of a plethora of applications across various sectors, which continue to multiply to this day.

Direct Versus Indirect Aluminum Extrusion Procedure

The aluminum extrusion process can be implemented through two primary procedures: direct and indirect extrusion. Both methods make use of a die to shape the aluminum, but the movement of the billet and the die vary between the two.

Direct Extrusion Process

In the direct, or forward, extrusion process, the billet and the ram move simultaneously in the same direction. To begin the process, a pre-heated aluminum billet is placed inside the container of the extrusion press.

A ram then pushes the billet against the extrusion die, forming the aluminum into the desired shape as it exits through the other end of the container. However, the direct method comes with its share of complexities due to the friction between the billet and the container, demanding a high level of force to push the billet through the die.

Unlike direct extrusion, the indirect, or reverse, extrusion process involves the stationary positioning of the die. During this process, the billet and container move in tandem, while the die remains fixed in place. This technique reduces friction significantly because the billet and the container move together. The indirect extrusion process, as such, requires less force and leads to a smoother, more precise extruded product.

Stepwise Breakdown of Aluminum Extrusion Operation

In order to further understand the aluminum extrusion process, it is essential to know each stage involved in this complex operation. It all starts from the fabrication of the extrusion die, to the final step of implementing additional processes on the extruded shapes.

1. Fabrication of the Extrusion Die

The initial phase in the aluminum extrusion process involves the fabrication of a die, which is a tool used to shape the aluminum. This die is typically made from hardened steel and is designed according to the profile of the final product. With the advancements in CNC milling and CNC machining, the fabrication of complex dies has become a more achievable task.


2. Pre-warming the Aluminum Billet

After the die has been fabricated, an aluminum billet is preheated to a certain temperature to prepare it for extrusion. The temperature of the billet must be carefully controlled as it directly affects the quality and the surface finish of the final product.


3. Relocation of the Billet to the Extrusion Press

Once the billet has been adequately pre-warmed, it is transferred to the container of the extrusion press. This container is specifically designed to withstand the extreme heat and pressure involved in the aluminum extrusion process.


4. Introduction of the Billet Substance into the Press Container

The pre-warmed billet is then introduced into the container of the extrusion press. In this stage, the billet is aligned properly with the die to ensure the formation of a proper shape during extrusion.


5. Compressing the Extruded Substance against the Die

After the billet is properly positioned, a high-pressure hydraulic ram is used to compress the aluminum against the extrusion die. The pressure causes the soft aluminum to flow through the die, thereby taking the shape of the die’s design.


6. Cooling Down the Extrusions Rapidly

Once the aluminum is extruded, it is critical to rapidly cool down the extruded profiles to preserve their shape and prevent distortion. This is usually achieved through a process called quenching, where the extruded aluminum is rapidly cooled using air, water, or a combination of both.


7. Cutting the Extrusions to Match Table Length

After cooling, the extruded profiles are then cut according to the length of the extrusion table. This is a critical step in the aluminum extrusion process as it ensures that the final products are of the desired length. Thanks to advancements in CNC machining, this cutting operation can be performed with high precision.


8.Bringing the Extrusions Down to Ambient Temperature

The extruded profiles are then allowed to cool down to ambient temperature. This cooling period is necessary to help the aluminum regain its strength and hardness, preparing it for any subsequent processes such as stretching, straightening, or aging.


9. Transporting the Extrusions to the Stretcher and Arranging Them

After reaching ambient temperature, the extruded aluminum profiles are transported to a stretcher. This device is used to straighten the extrusions and relieve any internal stresses that may have developed during the extrusion process. The extrusions are then arranged for further processing.


10. Trimming the Extrusions to the Desired Length

Following stretching and alignment, the extruded profiles are then cut or trimmed to their final, desired length. This involves the use of high-speed saws or other CNC milling techniques, which ensure a high degree of accuracy in the final product. The remnants from the trimming process are collected and recycled, affirming aluminum’s sustainability and cost-effectiveness.


11. Implementing Additional Processes

At this point, the extruded aluminum profiles may undergo various secondary processes as required. These processes can involve heat treatment, which enhances the profiles’ hardness and strength; surface finishing, which could involve anodizing or powder coating for enhanced appearance and corrosion resistance; or additional machining, such as CNC turning or drilling for more complex parts.

Various Forms Achievable Through Aluminum Extrusion

Aluminum extrusion allows for the production of a vast array of forms. These forms can generally be grouped into four main categories:

  1. Solid shapes: These are the most straightforward forms produced by aluminum extrusion. As the name suggests, solid shapes lack any openings or voids. An example could be a solid bar or rod.
  2. Hollow shapes: Hollow shapes, also known as tube or pipe profiles, have one or more voids running through them. They are achieved using special dies with “mandrels” or “bridges” that shape the inside of the profile.
  3. Semi-hollow shapes: Semi-hollow shapes fall somewhere between solid and hollow forms. These profiles have partially enclosed voids, often created to increase the strength-to-weight ratio or improve the extrusion’s aesthetic appeal.
  4. Custom or bespoke forms: The real power of aluminum extrusion lies in its ability to produce almost any shape a designer can imagine. With the use of custom-designed dies, complex cross-sectional profiles can be extruded to meet unique requirements.

Determinants of Aluminum Extrusion Outcome

The process of aluminum extrusion, while highly versatile, is also influenced by various factors that can significantly impact the final product. These factors can be grouped into several categories:

  1. Complexity of the extruded figures: The design complexity of the extrusion plays a significant role in the process. Complex shapes may require advanced CNC milling techniques or specially designed extrusion dies to achieve the desired results.
  2. Extrusion speed and its dependency on pressure and temperature: The speed at which the aluminum is extruded has a significant impact on the final product. Faster speeds can lead to changes in the aluminum’s structure, affecting the product’s strength and appearance
  3. Billet heat levels and their influence on precision and surface status: The temperature of the aluminum billet before and during the extrusion process is critical. Too much heat can cause the material to soften and deform, affecting the precision of the extrusion and the quality of the surface finish.
  4. The relation of extrusion ratio to the mechanical work: The extrusion ratio – the cross-sectional area of the billet to the cross-sectional area of the extruded product – directly relates to the amount of mechanical work involved in the extrusion process. A higher extrusion ratio generally requires more force, potentially affecting the product’s dimensional stability.
  5. Press operation and its influence on weight per unit length: The operation of the extrusion press also plays a significant role in the outcome of the extrusion process. For instance, inconsistent operation can result in uneven product lengths or variable weights per unit length.
  6. Tongue ratio and its contribution to extrusion efficiency: The tongue ratio – the area of the die opening to the total area of the die – influences the efficiency of the extrusion process and the quality of the final product. A higher tongue ratio can lead to increased friction and force requirements, affecting the overall efficiency and quality of the extrusion.

The Use of Aluminum Extrusions in Various Industries

The versatility and beneficial properties of aluminum, coupled with the adaptability of the extrusion process, have enabled aluminum extrusions to be widely used across a plethora of industries. The ability to create complex and custom shapes, in combination with aluminum’s light weight, strength, and resistance to corrosion, has made it a favorite choice for many sectors.

In the automotive industry, for instance, aluminum extrusions are being increasingly adopted to reduce vehicle weight and, in turn, enhance fuel efficiency. It’s common to find these extrusions in parts such as chassis, panels, bumpers, and engine components.

The construction industry also heavily relies on aluminum extrusions in the manufacture of window and door frames, curtain walls, solar panels, and more. The high strength-to-weight ratio and the ability to resist environmental elements make aluminum extrusions a go-to choice in this sector.

In the realm of electronics, aluminum’s excellent heat dissipation properties make it an ideal material for heat sinks and other cooling elements. It’s especially prominent in CNC machining electronics.

Furthermore, in the aerospace industry, the light weight and strength of aluminum, combined with its resistance to corrosion, make it a preferred material for various components, including fuselage panels, engine housings, and interior parts.

Given the broad range of shapes and forms achievable through aluminum extrusion, it’s not surprising that industries such as consumer goods manufacturing, medical equipment, and even renewable energy have found uses for extruded aluminum in their products.


To conclude, the aluminum extrusion process presents a unique method of producing custom profiles that are leveraged in an array of applications across different industries. From the automotive sector to construction, electronics, aerospace, and more, the reach and impact of aluminum extrusions continue to expand. This is largely due to the intrinsic properties of aluminum and the creativity that the extrusion process permits.

We at Worthy Hardware understand the critical role that aluminum extrusions play in the creation of a wide array of products. As such, we’ve committed ourselves to providing quality aluminum extrusion offerings that meet our clients’ diverse needs. Our extensive experience in the industry, coupled with our technologically advanced equipment, enables us to provide services that are nothing short of exceptional.

We invite you to explore more about our services and to see for yourself the Worthy Hardware difference. Feel free to contact us for more information, consultation, or to start a project. Also, consider signing up for our newsletter to stay up to date with the latest news, developments, and offerings in the world of aluminum extrusion and CNC machining.

Remember, at Worthy Hardware, we don’t just offer services. We offer solutions that are worthy of your trust.

Frequently Asked Questions (FAQ)


1. What is the aluminum extrusion process?

The aluminum extrusion process involves forcing pre-heated aluminum alloy material under high pressure through a die that has been designed to create the desired profile shape. It’s often compared to squeezing toothpaste out of a tube.


2. What types of products can be made with aluminum extrusion?

Aluminum extrusion can be used to create a wide variety of products, including automotive parts, airplane components, window frames, doors, and many more. The process allows for a great deal of flexibility in design, meaning it can be used to create very complex and intricate shapes.


3. What are the benefits of using aluminum extrusion?

The benefits of using aluminum extrusion include high strength-to-weight ratio, excellent thermal and electrical conductivity, corrosion resistance, and recyclability. Furthermore, extruded profiles can be finished in various ways to enhance aesthetics or increase durability.


4. What is the difference between direct and indirect extrusion?

In direct extrusion, the billet and ram move together, while the die is stationary. This is the most common method used in aluminum extrusion. Conversely, in indirect extrusion, the die moves along with the billet, while the container is stationary. This method reduces friction and allows for longer, more complex extrusions.