What is Aluminum Extrusion and Its Process
The use of aluminum extrusion in product design and manufacturing has increased dramatically in recent decades. You may have heard of this manufacturing process, but don’t understand how it works.
Today we will discuss the principles of aluminum extrusion, its benefits, types and steps of the process.
What is Aluminum Extrusion?
Aluminum extrusion is a plastic processing method that involves applying strong pressure to an aluminum billet placed in a die cavity (or barrel), forcing the billet to undergo a directional plastic deformation and extruding it out of the die hole in the extrusion die in order to obtain the desired cross-section shape.
A simple example we can give is the extrusion of toothpaste:
Pressure is applied from the outside of the toothpaste package to extrude the toothpaste from the tube.
To obtain different shapes of toothpaste, we need to add a mold to the tube so that the toothpaste can only be extruded in this direction.
By fixing the exit mold while applying pressure, we are able to extrude the toothpaste in the shape we want.
The exit of the toothpaste tube works in the same way as the mouth of the aluminum extrusion die.
We can refer to the following video from Hugh Aluminum:
What shapes can we extrude?
There are three main categories of extrusion shapes:
Each of these shapes can be customized according to the die used to design the extrusion (Hugh Aluminum has both die design and aluminum extrusion manufacturing)
Solid, with no closed voids or openings (e.g. H-beams, solid aluminum rods or bars).
Hollow, with one or more voids (e.g. square, round, rectangular, square tubes with grooves).
Semi-hollow, with partially closed voids (e.g. F-slots, C-slots, U-slots and T-slot aluminum profiles).
Preparation:
- Selection of suitable aluminum billet or bar as raw material to ensure that its chemical composition and physical properties meet the extrusion requirements.
- Designing and manufacturing the extrusion die, it is necessary to confirm that the shape of the extrusion die conforms to the dimensions required by the CAD drawings.
Heating:
- The aluminum billet or bar is placed in a heating furnace and heated to the proper temperature. The purpose of heating is to increase the plasticity and reduce the deformation resistance of the aluminum so that it can be more easily extruded through the die.
- The heating temperature and time are determined by the type of alloy, thickness, and extrusion requirements of the aluminum.
Belows video from Hugh Aluminum shows Heating process and extrusion for aluminum
Extrusion:
- The heated aluminum billet or bar is placed into the extrusion barrel of the extruder.
- Pressure is applied through the press head or screw of the extruder to force the aluminum through the die hole of the die.
- The shape of the die hole in the die determines the shape of the extruded aluminum section.
- During the extrusion process, parameters such as extrusion speed, pressure and temperature need to be controlled to ensure the quality and performance of the extruded product.
Cooling:
- Extruded aluminum usually requires a cooling process to quickly reduce its temperature and fix its shape.
- Cooling can be natural or forced (e.g., using water or air cooling).
Subsequent processing of aluminum after extrusion can include a variety of processes to meet different product needs and performance requirements.
The following are the subsequent processing steps:
1. Heat treatment:
Heat treatment is an integral part of aluminum alloy processing. It can change the internal structure and properties of the material, such as improving the hardness, strength and toughness. Common heat treatment methods include aging treatment, annealing treatment and so on.
2. Machining:
Machining is the process of cutting, grinding and other operations on aluminum alloy materials. Through machining, aluminum alloy materials can be further refined to meet the precision requirements of finished or semi-finished products. Common machining methods include milling, drilling, turning, grinding and so on.
Belows video shows CNC maching of aluminum profile
3. Surface treatment:
Surface treatment is a key step to improve the appearance quality and corrosion resistance of aluminum alloy materials. Common surface treatment methods include anodizing, spraying, plating, polishing, sandblasting and so on. These treatments can give aluminum alloy materials a variety of colors, luster and texture, and improve their corrosion and wear resistance.
Belows video shows aluminum extrusion surface treatment：
These subsequent processing steps can be used individually or in combination to meet different processing needs and workpiece forms. The specific processing method depends on factors such as product design requirements, performance requirements and cost budgets
Summary:
Aluminum extrusion is an important manufacturing process. It is a process for manufacturing parts with specific cross-sectional profiles by pushing a heated alloy material into a die. It produces shapes that can be diverse.
