What is Aluminum Extrusion? The Process in 10 Steps

The use of aluminum extrusion in product design and manufacturing has increased significantly in recent decades.

According to a recent report from Technavio, between 2019-2023 the growth of the global aluminum extrusion market will be accelerating with a Compound Annual Growth Rate (CAGR) of almost 4%.

Perhaps you’ve heard of this manufacturing process and are wondering what it is and how it works.

Today we’ll discuss what aluminum extrusion is, the benefits it offers, and the steps involved in the extrusion process.

We’ll begin with the most basic and essential question.

Step #1: The Extrusion Die is Prepared and Moved to the Extrusion Press

First, a round-shaped die is machined from H13 steel. Or, if one is already available, it is pulled from a warehouse like the one you see here.

Before extrusion, the die must be preheated to between 450-500 degrees celsius to help maximize its life and ensure even metal flow.

Once the die has been preheated, it can be loaded into the extrusion press.

Step #2: An Aluminum Billet is Preheated Before Extrusion

Next, a solid, cylindrical block of aluminum alloy, called a billet, is cut from a longer log of alloy material.

It is preheated in an oven, like this one, to between 400-500 degrees celsius.

This makes it malleable enough for the extrusion process but not molten.

Step #3: The Billet is Transferred to the Extrusion Press

Once the billet has been preheated, it is transferred mechanically to the extrusion press.

Before it is loaded onto the press, a lubricant (or release agent) is applied to it.

The release agent is also applied to the extrusion ram, to prevent the billet and ram from sticking together.

Step #4: The Ram Pushes the Billet Material into the Container

Now, the malleable billet is loaded into the extrusion press, where the hydraulic ram applies up to 15,000 tons of pressure to it.

As the ram applies pressure, the billet material is pushed into the container of the extrusion press.

The material expands to fill the walls of the container.

Step #5: The Extruded Material Emerges Through the Die

As the alloy material fills the container, it is now being pressed up against the extrusion die.

With continual pressure being applied to it, the aluminum material has nowhere to go except out through the opening(s) in the die.

It emerges from the die's opening in the shape of a fully-formed profile.

Step #6: Extrusions are Guided Along the Runout Table and Quenched

After emerging, the extrusion is gripped by a puller, like the one you see here, which guides it along the runout table at a speed that matches its exit from the press.

As it moves along the runout table, the profile is “quenched,” or uniformly cooled by a water bath or by fans above the table.

Step #7: Extrusions are Sheared to Table Length

Once an extrusion reaches its full table length, it is sheared by a hot saw to separate it from the extrusion process.

At every step of the process, temperature plays an important role.

Although the extrusion was quenched after exiting the press, it has not yet fully cooled.

Step #8: Extrusions are Cooled to Room Temperature

After shearing, table-length extrusions are mechanically transferred from the runout table to a cooling table, like the one you see here.