How is aluminum sheet processed into aluminum foil?

The process of converting aluminum sheet into aluminum foil involves several steps, including casting, rolling and finishing.

The process of processing aluminum plates into aluminum foil mainly includes the following steps:
Aluminum plates and aluminum foil are both deep-processing raw materials for aluminum alloys. Aluminum plates are usually rolled and cut from aluminum ingots. Aluminum foil has a thin thickness. How is it processed? The forming of aluminum foil is similar to that of aluminum plate, both of which are obtained by processing raw materials.

The raw material for aluminum foil die casting is aluminum plate, and the process of converting aluminum plate into aluminum foil involves several steps, including casting, rolling and finishing.

aluminum sheet processed into aluminum foil
aluminum sheet processed into aluminum foil

Raw material:

Aluminum plate: the main raw material for aluminum foil production. These aluminum panels are usually made from primary or recycled aluminum.

The process of turning aluminum plate into aluminum foil

Melting: Aluminum sheets are melted in a furnace at temperatures in excess of 660°C (1220°F).
Alloying: During the melting process, other metals (such as copper, manganese, magnesium, silicon, or zinc) can be added to form alloys with desired properties (strength, flexibility, etc.).
Casting: The molten aluminum is then cast into large slabs (also called aluminum billets or rolled slabs) through a process called direct cold casting (DC) casting. This involves pouring molten aluminum into a mold and rapidly cooling it with water.

Hot rolled aluminum sheet

Preheat: Preheat the aluminum sheet to around 400-500°C (750-930°F) to make it more malleable.
Hot Rolling Mill**: A preheated slab passes through a series of rolling mills that apply pressure to reduce its thickness. The process is done in several stages, gradually reducing the board thickness from about 600 mm (24 inches) to about 2-6 mm (0.08-0.24 inches).

Cold rolled

Cooling: After hot rolling, let the aluminum plate cool.
Cold rolling mill: The cooled plates are further rolled in cold rolling mills at room temperature. This process further reduces the thickness, to about 0.1-0.2 mm (0.004-0.008 inches). Cold rolling also increases the strength and hardness of aluminum.

foil roll

Initial scroll:

Intermediate foil rolling: Cold rolled aluminum sheets are further processed in specialized foil rolling mills. These grinders use a combination of high pressure and precise control to reduce thickness to around 0.005-0.02 mm (0.0002-0.0008 inches).

Final scroll:

Double Reduction: To achieve the final foil thickness, aluminum can be rolled through a process called double reduction. This involves rolling two pieces of paper together and then separating them at the end. This helps achieve the ultra-thin specifications required for foil, typically as low as 0.006 mm (0.00024 inches) or less.

Annealing: Rolled aluminum is typically annealed (heated to around 300-400°C) to relieve stress and improve ductility.

Surface treatment:

Lubrication and coating: To facilitate further processing and improve performance, foils can be lubricated or coated. This can include adding oils, varnishes or other surface treatments to improve usability, corrosion resistance or adhesion to other materials.

Slitting and cutting:

Slitting: Use a precision slitting machine to cut wide rolls of aluminum foil into narrower rolls. This is done according to the customer’s width and length specifications.
Cutting: You can also cut the foil into thin slices if desired.

Inspection: Finished aluminum foil is inspected for quality, including thickness uniformity, surface finish and absence of defects.
Packaging: Aluminum foil rolls or sheets are packaged to protect them from damage during shipping and storage. This may involve wrapping and boxing with protective materials.

The process of converting aluminum sheet into aluminum foil involves melting and alloying aluminum ingots, casting them into slabs, hot and cold rolling the slabs into plates, and finally rolling the plates into thin foils.