The thick aluminum foil is with a thickness between 0.1mm and 0.2mm such as 30 gauge aluminum foil and 38 gauge aluminum foil. The thickness of 30 gauge aluminum foil is 0.254mm and the thickness of 38 gauge aluminum foil is 0.102mm. The thick aluminum foil is usually used in container foils, architectural decoration and industrial purposes.
The raw material must be reduced in thickness to make the aluminum foil. As the aluminum sheets pass through the rolls, they are extruded thinner. The work rolls are paired with heavier rolls called backup rolls, which apply pressure to help keep the work rolls stable. This helps keep product dimensions within tolerance. Lubricants are added to facilitate the rolling process. During this rolling process, aluminum must sometimes be annealed (heat treated) to maintain its machinability.
The roll gap determines the thickness and length of the aluminum foil leaving the rolling mill. This gap can be adjusted by raising or lowering the upper work roll. Rolling on the aluminum foil yields two natural finishes, bright and matte side. When the aluminium foil comes into contact with the work roll surface, a shiny finish is produced.
As the aluminum foil passes through the rollers, it is trimmed and cut with circular or razor-like knives mounted on roller mills. Trimming refers to the edges of the foil, while slitting involves cutting the aluminum foil into pieces.
Aluminum foil is used in combination with other materials in many applications. It can be coated with a variety of materials such as polymers and resins for decorative, protective or heat sealing purposes. It can be laminated to paper, cardboard and plastic film. It can also be cut, printed, embossed.
In addition to process control of parameters such as temperature and time, the finished aluminum foil must meet certain requirements. For example, different applications has different requirements on its dryness. Wettability tests are used to test dryness. Other important properties are thickness and tensile strength.
The packaging of 38 gauge aluminum foil rolls should be sealed, and each roll should be filled with an appropriate amount of desiccant. The humidity of wooden box should not exceed 18%, and the temperature of packing aluminum coils should not exceed 45 degrees Celsius. Do not open the sealed package immediately when transporting from a low-temperature area to an area with high temperature and high humidity.