[China Aluminum Network] The main disadvantages of aluminum foil are:

(1) Pinhole. Pinholes are the primary drawback of aluminum foils. In the original guess, the rolling mill, rolling oil, and even dust in the air reaching the 6μm metric into the roll gap will all lead to pinholes, so 6μm aluminum foil without pinholes is impossible and can only be evaluated by how much and the size of it. Because of the improvement of aluminum foil rolling conditions, especially the useful filtering of dust and rolling oil and the convenient setting of the roll changing system, the number of pinholes in aluminum foil is increasingly dependent on the metallurgical quality and processing defects of the material because the pinhole is generally With the drop of material defects, it is difficult to find the correspondence with the original defects. Generally speaking, the pinhole is mainly related to gas content, impurity, compound and composition segregation. The adoption of useful aluminum liquid purification, filtration, and grain refinement all contribute to the reduction of pinholes. Of course, the use of alloying techniques to improve the hardening properties of the data also helps to reduce pinholes. High-quality hot-rolled 6μm aluminum foil pinholes can be less than 100/inch. When the material is better, the pinhole of 6μm aluminum foil is less than 200/?. In the aluminum foil rolling process, other elements that make up pinholes are also many, even catastrophic, and thousands of pinholes per square meter are not uncommon. The useful filtering of rolling oil, short-term replacement of rolls and dust prevention methods are all necessary conditions to reduce the pinholes of aluminum foil. With large rolling force, small tension rolling can also help to reduce pinholes.

(2) Roll, roller, and uneven gloss. It is mainly the aluminum foil defects caused by the roller, divided into three types: point, line, and surface. The more distinctive features are presented in three cycles. The main reasons for this disadvantage are: incorrect grinding of the roller; damage to the roller due to foreign objects: inadvertent failure of the roller; fatigue of the roller; collision and slippage between the rollers. All the elements that can cause damage to the roll surface can damage aluminum foil. Because aluminum foil rolling surface finish is very high, subtle gloss unevenness will affect its appearance. Regular cleaning of the rolling mill, insisting on the cleaning of the rolling mill, ensuring the normal operation of the cleaning roll, regular roll change, and reasonable grinding are the basic conditions for ensuring uniform and common appearance of the aluminum foil after rolling.

(3) Wrinkle. Because of the poor shape of the plate, wrinkles are formed when the aluminum foil is coiled or unrolled, and its nature is a lack of tension to flatten the foil surface. Regarding the device of tension 20 MPa, the shape of the foil surface must not be greater than 30I. When it is greater than 30I, it must wrinkle. Because the aluminum foil is generally subjected to more tension than the subsequent processing during rolling, some of them are only manifested as poor shape during rolling, including incorrect roll grinding, incorrect roll shape, poor shape of the incoming material, and incorrect adjustment of the plate shape.

(4) bright spots, bright spots, bright spots. Due to the improper use of double oil, the bright spots, bright spots, and bright spots on the double-skin surface are mainly due to the lack of strength of the double oil film or uneven roll surface, which leads to uneven rolling and the appearance of a skin or foreign material. . Choosing a reasonable double oil, insisting on incoming cleaning and even roll surface uniformity is a useful way to deal with such shortcomings. Of course, it is also necessary to change the amount of reduction and select excellent aluminum plates.

(5) Thickness difference. Thickness is difficult to control is a feature of aluminum foil rolling, 3% of the thickness difference may not be difficult when the production of the plate, but in the production of aluminum foil is very difficult. The reason is that the thickness is thin, and other trace conditions can affect the temperature, oil film, and oil and gas concentration. Rolling aluminum foil can reach hundreds of thousands of meters. The rolling time is as long as 10 hours. With the extension of time, the thickness difference is very easy to construct, and the thickness adjustment method has only tension speed. These elements all constitute the hard control of aluminum foil rolling. Therefore, the actual manipulated thickness difference is within 3%, and many conditions are required to ensure that it is quite difficult.

(6) Oil pollution. Oil stain refers to the remaining oil on the outer surface of the aluminum foil after rolling, that is, oil other than the rolling oil film. These oils are generally thrown at the roll neck or at the exit of the mill, splashed, and dripped on the foil surface, and are relatively dirty and have a messy composition. The outer surface of the aluminum foil is more oily than other rolled materials. First, because aluminum foil products are mostly used as decoration or packaging materials, it is necessary to have a clean appearance. Second, the thickness of the aluminum foil is thin, and it is easy to form a bubble when annealing the rear lane. , And because the amount of oil in the site is too much to form an excessive residue and affect the application. How much is the disadvantage of oil pollution is an important indicator to evaluate the quality of aluminum foil.

(7) Water spots. Water spot refers to the presence of water droplets on the foil surface before rolling and white traces formed after rolling. When it is fine, it will affect the appearance of the foil surface. When it is severe, it will lead to a broken belt. The water spot is formed by the presence of water droplets in the oil or drops of water on the surface of the foil in the rolling mill. Manipulation of the water in the oil and the water source is a special method to prevent water spots.

(8) Resonance marks. The oscillating mark refers to the periodic transverse wave of the aluminum foil. There are two kinds of chattering causes: one is because the roller is formed during grinding and the cycle is about 10~20mm; the other is that when the rolling is performed, the oil film does not oscillate successively and often occurs in a speed zone with a period of 5 cycles. ~10mm. The cause of the occurrence of chatter marks is the lack of oil film strength, which can generally be eliminated by using an improved smooth condition.

(9) Tension line. When the thickness reaches 0.015mm or less, a parallel stripe is formed in the longitudinal direction of the aluminum foil, commonly called a tension wire. The tension line distance is about 5~20 mm, the smaller the tension, the wider the tension line and the more pronounced the stripes. When the tension reaches a certain value, the tension line is subtle or even missing. The smaller the thickness is, the greater the possibility of occurrence of tension threads is, and the possibility of double tension rolling is greater than that of single sheets. Increasing tension and roll roughness is a useful way to reduce or eliminate tension lines, and large tensions must be based on an outstanding plate shape.

(10) Open seams. Slotting is a unique disadvantage of foil rolling, which cracks straight in the longitudinal direction during rolling, often accompanied by metal wire. The bottom edge of the seam is discounted on the side of the entrance, which often occurs in the center, mainly because of guessing the loose center or poor roll. Severe slits cannot be rolled, and fine slits are split at the time of future slitting, which generally constitutes a lot of waste.

(11) Airway. At the time of rolling, it was broken and crushed in strips. The edge was a droplet-shaped curve with a certain width. The mild airway was not crushed and was white strips with dense pinholes. The presence of a pinhole in the front and rear ends of crushed aluminum foil is the primary symbol of airway and other shortcomings. The airway originates from the material. It is very important to select the material with low gas content as the aluminum blank.

(12) Coiling shortcomings. The disadvantages of rewinding mainly refer to loose or loose inner tightness. Because of the limited tension on the foil, winding a hard roll is difficult. It is desirable to obtain a roll with tight outer core, and the tension to be satisfied is a condition that constitutes a certain tension gradient. Therefore, the coiling quality depends on the shape of the board. The outer coils of the inner shaft form a horizontal edge, while the loose coils form an ellipse, which will affect the future processing.

Although there are many disadvantages in aluminum foil rolling, it is mainly reflected in the following aspects: pin holes, roll eyes, slits, and air passages characterized by holes; oil, uneven gloss, vibration marks, tension lines, etc. Water spots, bright light spots; to affect the post-process processing of the plate shape, wrinkling, discounts, coiling bad; thickness characteristics such as the thickness difference. In fact, the unique disadvantages of aluminum foil as long as the pinhole class, the other several defects are the same plate, but the degree of severity is not the same or different requirements.

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