How is aluminum foil produced?

Cast-rolled aluminum foil production process

Aluminum liquid, aluminum ingot -> Smelt -> Continuous roll casting -> Winding -> Cast roll finished product

Plain foil production process

Plain foil -> Cast-rolled coil -> Cold rolled -> Foil rolling -> Slitting -> Annealing -> Plain foil finished product

The manufacture of aluminum foil is similar to making pasta at home. A large block of almost pure aluminum is rolled several times through giant steel rolls, thereby reducing the thickness of the aluminum block and spreading it out to make it longer. Lubricants are added during the rolling process to facilitate operation. Each time the roller passes continuously, the thickness becomes thinner. Repeat the process until the foil thickness is reached, and then cut the large aluminum foil to the required width.

This may seem simple, but the actual process may not be easy. For example, when aluminum is pushed out, it heats up. If the temperature is too high, it will stick to the roller, so the pressure on the roller must be carefully controlled.

When the thickness of the aluminum plate is 5mm, it must be rolled again in the cold rolling stage. First, the sheet is rolled on a roll, and then sent to the cold rolling mill for final rolling. It is at this point that the bright and dark side of aluminum is created. Because aluminum foil is too thin today, the tension required to transport the aluminum through the cold rollers can easily break the aluminum. Since the aluminum sheet has two sides, the aluminum surface in contact with the steel roller becomes smoother and more shiny, and the aluminum surface in contact with itself becomes matte.

Rolling Mill Classification

The coil rolling mill is divided into two-high, four-high, six-high and multi-high cold rolling mills according to the number of rolls. The rolling mills currently used by our company are all four-high rolling mills.

When rolling in a four-high rolling mill, the rolling pressure is transmitted to the support roll through the roll body of the work roll. Mainly the support roller bears the load and produces deflection. Generally, the diameter of the support roll is 2-4 times larger than that of the work roll, so the deflection is greatly reduced. In order to further reduce the deflection and deformation of the rolling work rolls, a roll bending control system is installed on the four-high rolling mill. The four-high rolling mill is the most widely used rolling mill in cold rolling processing, and it has a large number of applications at home and abroad. The equipment of an ordinary four-high rolling mill includes an uncoiler, an entrance deflector roller, a tension roller, a work roller, a support roller, an exit guide roller or a plate-shaped roller, a coiler and related supporting equipment.

Four-high mill equipment composition

  1. Uncoiler
  2. Entrance deflector roller
  3. Five roller tension roller
  4. Work roll
  5. Support roller
  6. Outlet guide roller or profile roller
  7. Coiler

Principles for formulating aluminum foil rolling process:

The formulation of the aluminum foil rolling production process is based on the variety of alloys produced, the specifications of the finished products, the product quality requirements, the amount of output, the specifications and models of the equipment, the production capacity, the operating technology level, and the management level. When formulating a reasonable production process, the following principles should be considered:

  1. Make full use of the plasticity of metal, reasonably allocate pass processing rate, reduce rolling pass, shorten production cycle, and improve labor productivity.
  2. Obtain high-quality products that meet the requirements of technical conditions, increase yield and reduce costs.
  3. Under the conditions of safe operation, give full play to the capabilities of the equipment and try to balance the load of each machine.

Basic concepts of rolling process-rolling oil

Composition of rolling oil:

Rolling oil consists of base oil and additives. The base oil is the carrier of the additives, which plays a role of cooling and cleaning, and has very little lubricating effect. The lubricating medium is mainly realized by additives.

The main function of rolling oil:

  • Lubrication - reduce the friction between the roll and the aluminum foil, provide a stable friction interface, achieve stable rolling, and improve the surface quality.
  • Cooling - Take away the heat of deformation and friction of the metal, adjust the surface temperature of the roll, and control the shape of the roll by controlling the roll shape.
  • Cleaning - Clean the aluminum powder on the surface of the aluminum foil and the saponification and aluminum powder in the frame.
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