Aluminum Foil Roll

Contents:
What is aluminum foil roll?
Types of aluminum foil roll
    Thickness of aluminum foil roll
    Shape of aluminum foil roll
    Surface state of aluminum foil roll
    Processing status of aluminum foil roll
Features of aluminum foil roll
Rolling of aluminum foil
How to buy aluminum foil roll?

Aluminum foil roll is a stamping material in which metallic aluminum is calendered directly into thin sheets. Its stamping effect is similar to that of pure silver foil, which is why it is also called a “fake silver foil“. Since aluminum is soft, ductile, and has a silvery-white luster, the calendered sheet can be printed by applying sodium silicate and other substances to the offset paper to make aluminum foil. However, aluminum foil itself is prone to oxidation and color darkening, and it loses color when rubbed or touched, so it is not suitable for long-lasting book covers and other hot stampings. Because of its excellent characteristics, aluminum foil is widely used in food, beverage, cigarette, medicine, photographic backing, household daily necessities, laboratory, etc.

Aluminum foil roll can be divided into heavy gauge foil, medium gauge foil, and light gauge foil according to the difference in thickness.

Aluminum foil roll can be divided into hard foil, semi-hard foil, and soft foil according to their status.

Hard foil is the aluminum foil that has not been softened (annealed) after rolling. If it is not degreased, there will be residual swathes on the surface. Therefore, it must be degreased before printing, laminating, and coating. It can be used directly if it is used for forming process.

Aluminum foil whose hardness (or strength) is between hard foil and soft foil, usually used for forming process.

Aluminum foil that has been rolled and then fully annealed and softened to soft material with no oil residue on the surface. Most applications, such as packaging, laminating, and electrical materials, use soft foil.

Aluminum foil can be divided into one-sided glossy aluminum foil and two-sided glossy aluminum foil according to its surface condition.

One-sided aluminum foil is a double-rolled aluminum foil. It is called one-sided aluminum foil when one side is shiny and the other side is opaque after unwinding. Usually, one-sided aluminum foil does not exceed 0.025mm in thickness.

Double-sided aluminum foil is a single sheet of rolled aluminum foil. Both sides are in contact with the rolls. Depending on the surface roughness of the roll, the two sides of the aluminum foil are divided into two-sided aluminum foil with a mirror surface and two-sided aluminum foil with a normal surface. Usually, two-sided aluminum foil is generally not less than 0.01mm in thickness.

Aluminum foil can be divided into plain foil, embossed foil, laminated foil, coated foil, colored aluminum foil, and printed aluminum foil by processing state.

a. The surface of the aluminum foil roll is so clean and hygienic that no bacteria or microorganisms can grow on its surface.

b. Aluminum foil is a non-toxic packaging material, which can be in direct contact with food without any health hazards.

c. Aluminum foil is a tasteless and odorless packaging material, and will not cause any odor to the packaged food.

d. If the aluminum foil is not volatile, it will never dry out or shrink on its own or the packaged food.

e. There is no grease penetration in aluminum foil, whether at high or low temperatures.

f. Aluminum foil is an opaque packaging material, so it is a good packaging material for products exposed to sunlight lines, such as margarine.

g. Aluminum foil is very malleable, so it can be used to package various shapes of products. It can also be made into various shapes of containers at will.

h. Aluminum foil has high hardness and high-tension strength, but its tear strength is small, so it is extremely easy to tear.

i. Aluminum foil cannot be heat-sealed and must be coated with the material that can be heated, such as pe, on its surface to be heat-sealed.

j. Aluminum foil may have adverse reactions when in contact with other heavy metals or heavy metal types.

In the production of double foil, the rolling of aluminum foil is divided into three processes: rough rolling, medium rolling, and finishing rolling. From a process point of view, they can be broadly divided in terms of rolling exit thickness.

Making the aluminum strip thinner mainly depends on the rolling force, so the automatic plate thickness control method is the main control method of AGC with a constant roll slit, even if the rolling force changes, adjusting the roll slit at any time to keep the roll slit at a certain value can obtain the strip of uniform thickness.

In the case of aluminum foil rolling to medium-finish rolling, due to the extremely thin thickness of aluminum foil, when rolling, it is easier to increase the rolling force and make the rolls produce elastic deformation than the rolled material produces plastic deformation. The elastic flattening of the rolls cannot be ignored. Aluminum foil rolling is generally a roll less rolling under constant pressure conditions, and adjusting the thickness of aluminum foil mainly relies on adjusting the post-tension and rolling speed.

For very thin aluminum foil with a thickness of less than 0.012mm (thickness size is related to the diameter of the working roll), it is very difficult to roll the foil in a single sheet due to the elastic flattening of the rolls, so the method of double rolling is used, i.e., two sheets of aluminum foil are added with lubricant in the middle and then rolled together (also called stack rolling).

Stack rolling not only produces extremely thin aluminum foil that cannot be produced by single rolling but also reduces the number of strip breaks and increases labor productivity. With this process, single-sided glossy aluminum foil of 0.006mm to 0.03mm can be mass-produced.

During the rolling of aluminum foil, the phenomenon that the thickness of the foil becomes thinner as the rolling system ramps up is called the speed effect. The explanation of the mechanism of the velocity effect has yet to be thoroughly investigated. The causes of the velocity effect are generally considered to be the following three aspects.

a. The friction state between the work roll and the rolling material changes. As the rolling speed increases, the amount of lubricant brought in increases, which results in a change in the lubrication state between the roll and the rolling material. The friction coefficient decreases, the oil film becomes thicker, and the thickness of the aluminum foil is then thinned.

b. Changes in the rolling mill. With the use of cylindrical bearings in the mill, as the rolling speed increases, the roll neck will float in the bearing, thus making the two interactions of the loaded rolls will move in the direction of mutual tightness.

c. The material is softened by the process when it is rolled and deformed. High-speed aluminum foil rolling mill rolling speed is very high, as the rolling speed increases, the temperature of the rolling deformation zone opens high, according to calculations, the metal temperature in the deformation zone can rise to 200 ℃, equivalent to an intermediate recovery annealing, thus causing the processing softening phenomenon of the rolled material.

The total processing rate refers to the total deformation of the foil after recrystallization and annealing until the finished product is rolled. Generally speaking, the total processing rate of 1 series can reach more than 99%, and some 8 series products can also reach this value, but the total processing rate of aluminum foil is generally below 90%.

Processing rate is determined by the core of the rolling process. For pure aluminum series products, the processing rate can reach 65%. The first pass after annealing the billet should not use too large processing rate, which generally takes about 50%.

Thickness measurement methods during aluminum foil rolling are mainly eddy current thickness measurement, isotope ray thickness measurement, and X-ray thickness measurement. X-ray thickness measurement is one of the most common thickness measurement methods used in aluminum foil production, especially in high-speed aluminum foil rolling mills. Thickness control methods during aluminum foil rolling: rolling force control, tension control, rolling speed control, tension/speed, speed or tension control.

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