The applications of aluminum extrusion in manufacturing and product development have grown exponentially during the last decades. In fact, according to a recent market study, it will increase by 4% between 2019 to 2023.

You may have heard of aluminum extrusion but the process and how it works may not be familiar to you.

In this article, we will take a deep look into the aluminum extrusion and the steps involved in the process.

What is Aluminum Extrusion?

Extrusion is the process of shaping a material like aluminum by forcing it to flow through an opening, The extruded material will come out as an elongated shape with the same profile as the opening.

Think of a toothpaste being squeezed from a tube. As the toothpaste emerges, it will take the shape of the tube’s opening. This opening is your extrusion die and since it is a solid circle, the toothpaste will be squeezed out in a long solid extrusion.

In theory, the aluminum extrusion process is simple to understand. But how can a sheet of metal pass the die?

Steps Involved In Aluminum Extrusion

Step 1. Preparation of the Extrusion Die

In aluminum extrusion, the die is made from H13 steel. Before extrusion, this has to be pre-heated between 450 to 500 degrees Celsius to ensure the consistent flow of metal. Once heated, it will be moved in the extrusion press.

Step 2. Preheating of Aluminum Billet

The next step in the process is the preparation of the aluminum billet. This is a circular block of aluminum billet which is cut from a log of metal alloy. The billet will be heated in an oven set at 400 to 500 degrees. The heating process is critical to render the material malleable for the extrusion process.

Step 3. Transferring the Billet into the Extrusion Press

Once the preheating temperature is achieved, the billet is transferred into the mechanical press. Before loading, a lubricating agent will be applied both to the billet and the extrusion ram to prevent the two from sticking together.

Step 4. Pushing the Billet into the Container

After loading the malleable billet, the hydraulic ram will apply up to 15,000 tons of pressure to push the material into the extrusion press. The material will expand to fill the walls of the material.

Step 5. Emerging Through The Die

While the alloy fills the container in the extrusion press, it will be pressed into the extrusion die. With continuous pressure, it will come out of the die’s opening and take its shape.

Step 6. Moving Along the Runout Table and Quenching

The extruded material will be gripped by a puller at a fast speed and will be guided along with the runout table. As it runs along, the material is doused with water to cool them.

Step 7. Shearing

Once the extruded material reaches the desired length, it will be sheared using a hot saw. Temperature is critical in aluminum extrusion and while it was cooled down with water, the material has not fully cooled.

Step 8. Cooling at Room Temperature

After shearing the cut extruded material will be transferred from the runout table into the cooling table. It will maintain its profile until it has cooled to room temperature.

Step 9. Stretching

The extruded material has undergone an extreme process. To straighten the alloy, it will be moved into the stretcher where both of its ends are mechanically gripped. Pulling will ensue until it is fully straight and has achieved the right specifications.

Step 10. Finishing

Once the extrusion process is completed, it will be heat treated to enhance its properties. Other finishing steps may be applied, depending on its applications.