The use of aluminum extrusion in product design and manufacturing has increased significantly in recent decades.
According to a recent report by Technavio, between 2019 and 2023 the growth of the global aluminum extrusion market will accelerate with a compound annual growth rate (CAGR) of almost 4%.
You may have heard of this manufacturing process and are wondering what it is and how it works.
Today we will discuss what aluminum extrusion is, the benefits it offers, and the steps involved in the extrusion process.
We will start with the most basic and essential question.
What is Aluminum Extrusion?
Aluminum extrusion is a process whereby aluminum alloy material is forced through a die with a specific cross-sectional profile.
A powerful ram pushes the aluminum through the die and out of the die opening.
When it does, it comes out in the same shape as the die and is drawn along a teeing ground.
At a fundamental level, the aluminium extrusion process is relatively straightforward to understand.
The applied force can be compared to the force you apply when squeezing a tube of toothpaste with your fingers.
As you squeeze, the toothpaste emerges in the shape of the tube opening.
The toothpaste tube opening performs essentially the same function as an extrusion die. Since the opening is a solid circle, the toothpaste will come out as a long, solid extrusion.
Below you can see examples of some of the most commonly extruded shapes: angles, channels, and round tubes.
At the top are the drawings used to create the dies and at the bottom are renderings of what the finished aluminum profiles will look like.
The Aluminum Extrusion Process in 10 Steps
Step # 1: The extrusion die is prepared and transferred 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 between 450 and 500 degrees Celsius to help maximize its life and ensure a smooth flow of the metal. Once the die has been preheated, it can be loaded into the extrusion press.
Step 2: An aluminum bill is preheated before extrusion
Next, a solid cylindrical block of aluminum alloy, called a billet, is cut from a longer log of alloy material as it came from one of the best aluminium company in Chennai. It is preheated in an oven, like this one, between 400-500 degrees Celsius. This makes it malleable enough for the extrusion process but not cast.
Step # 3: the bill is transferred to the extrusion press
Once the billet has been preheated, it is mechanically transferred to the extrusion press. Before loading it into the press, a lubricant (or mold release agent) is applied to it. The release agent is also applied to the extrusion piston, to prevent the billet and piston from sticking together.
Step n. 4: the ram pushes the bill 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 as learnt from Tamilnadu aluminium company. As the ram applies pressure, the billet material is pushed into the extrusion press container. The find more material expands to fill the walls of the container.
Step # 5: extruded material emerges through die
As the alloy material fills the container, it is now pressed against the extrusion die.
With the continuous pressure applied to it, the aluminum material has nowhere to go except through the openings in the die.
It comes out of the die opening in the form of a fully formed profile.
Step # 6: Extrusions are guided along the eccentricity table and turned off
After emerging, the extrusion is grabbed by a puller, like the one you see here, which guides it along the exit table at a speed that matches its exit from the press.
As it moves across the outlet table for aluminium profile manufacturers, the profile is "turned off" or evenly cooled by a water bath or fans on the table.
Step # 7: the extrusions are cut to the length of the table
Once an extrusion reaches the full length of the table, it is cut with a hot saw to separate it from the extrusion process.
In every step of the process, temperature plays an important role.
Although the extrusion cooled down after exiting the press, it has not yet cooled down completely.
Step # 8: Extrusions are cooled to room temperature
After shearing, the table-length extrusions are mechanically transferred from the exit table to a cooling table, like the one you see here.
The profiles will stay there until they reach room temperature.
Once they do, they will need to be stretched.
Step # 9: Extrusions are moved onto the stretcher and stretched to align
Some natural twisting has occurred in the profiles and this must be corrected.
To correct this, they are transferred to a stretcher.
Each profile is mechanically clamped at both ends and pulled until completely straight and conformed to specification.
Step # 10: Extrusions are moved to the finishing saw and cut to size
With the table-length extrusions now straight and fully hardened, they are transferred to the saw table. Here, they are cut to preset lengths, usually between 8 and 21 feet long. At this point, the extrusion properties match the T4 temper. After sawing, they can be moved to an aging oven to age to T5 or T6 temper.
Summary: Aluminum extrusion is an important manufacturing process
Aluminum extrusion is a process for creating parts with specific cross-sectional profiles by pushing heated alloy material through a die.
The created shapes can be solid, hollow and semi-hollow; and they can be simple or complex.
The extrusion process is interesting, resulting in 8-24 foot long profiles that can then be heat treated, finished and manufactured to customer specifications.