Basic knowledge and technological process of aluminum extrusion

The composition of the aluminum alloy varies according to the type and number of added elements added to aluminum. Cast aluminum is the raw material used in the aluminum extrusion process.

The tool used to make a specific section of aluminum profile is called aluminum extrusion die. The mold is made of steel and has openings (or possibly several) of the desired contour shape.

Aluminum extrusion die

Aluminum extrusion die

The aluminum extrusion process depends largely on heat. Monitoring temperature from start to finish is critical to ensure that aluminum alloy properties (such as tensile strength and yield strength) are met and affect the final finish of the part.

The aluminum extrusion process starts by heating the aluminum ingot or aluminum rod to 400-480°C (750-900°F). Aluminum alloys are still solid, but have ductility. Does not emit light when heated; aluminum looks the same whether it is hot or cold.

The heated aluminum billet is transferred to an aluminum extrusion container. A hydraulic pressure is applied to the aluminum billet to force the aluminum to fill the container.

The pressure inside the container increases, forcing the aluminum alloy through the opening in the aluminum extrusion die. The result is a long, consistent shape of aluminum from the other side of the die, that is, an aluminum extruded profile.

The extrusion speed of the profile depends on the size of the part, the difficulty of the profile, the wall thickness, the choice of aluminum alloy and/or the number of cavities or openings in the aluminum extrusion die.

Extend along the extrusion table by means of a puller (a jaw-like mechanical device, clamped on the material and guiding the aluminum profile when it comes out of the die).

Aluminum extrusion machine (extrusion production line)

Aluminum extrusion machine (extrusion production line)

When the aluminum extruded profile comes out of the die, the temperature is in the range of 510-550°C. Assist cooling of aluminum profiles by using fans and/or water spray or complete water quenching. Aluminum must be cooled at a specified rate to meet the performance of aluminum alloys. The temperature is measured several times throughout the process to ensure that the goal is reached.

The longer aluminum profile is mechanically transferred to a cooling table to cool to room temperature. The cooled length is then stretched. Stretching is a mechanical process by which the aluminum profile is stretched to make the parts straight.

According to the order requirements, the stretched part is cut to a length usually between 6 and 30 feet.

The phenomenon that the strength and hardness of the aluminum alloy increase significantly with time after quenching is called aging. The final "heat treatment" step is to artificially aging the aluminum profile to achieve the required hardness. Aging can occur at room temperature, which is called natural aging, or it can occur in a certain temperature range (such as 100 to 200 ℃) above room temperature, which is called artificial aging. Basically, they are kept in an aging furnace for up to 8 hours. Artificial aging shortens the processing time.

Aging materials can be delivered to customers at any time or continue to be processed, such as CNC processing and other mechanical processing.