Although there are many kinds of aluminum foil rolling defects, they are mainly manifested as: pinhole, roll hole, seam opening and air passage characterized by holes; Oil stains, uneven luster, vibration marks, tension lines, water spots and bright spots characterized by surface conditions; In order to affect the shape of the plate, wrinkle, discount, bad coiling process; A thickness difference characterized by size. In essence, aluminum foil unique defects only a kind of pinhole, several other defects of the plate also have the same, but the performance of the severity of different or different requirements.

1.pinhole. Pinhole is the main defect of aluminum foil. Raw materials, rolls, rolling oil, and even dust in the air size of about 6μm into the roll gap will cause pinholes, so 6μm aluminum foil without pinholes is impossible, can only be evaluated by how much and size. Due to the improvement of aluminum foil rolling conditions, especially the effective filtration of dust and rolling oil and the setting of convenient roll change system, the number of aluminum foil pinholes increasingly depends on the metallurgical quality of raw materials and processing defects, because pinholes are often raw material defects fall off, it is difficult to find the corresponding relationship with the original defects. It is generally believed that pinholes are mainly related to gas content, inclusions, compounds and component segregation. Effective purification, filtration and grain refinement of liquid aluminum are helpful to reduce pinhole. Of course, alloying and other means to improve the hardening properties of materials can also help reduce pinhole. High quality hot rolled material rolling 6μm aluminum foil pinholes can be less than 100 /㎡. When the purification is good, 6μm aluminum foil pinholes in 200 / square meters or less. Other causes of pinholes in the aluminum foil rolling process are numerous, even catastrophic, and thousands of pinholes per square meter are not uncommon. Effective filtering of rolling oil, short-term change of roll and dustproof measures are necessary conditions to reduce pinholes in aluminum foil, and large rolling force and small tension rolling will also help to reduce pinholes.

2.roll printing, roll eye, uneven luster. It is mainly caused by roller aluminum foil defects, divided into point, line, surface three. The main reasons for this defect are: incorrect grinding of roll; Foreign material damage roll: incoming material defect imprint injury roll; Roll fatigue; Roller impact, skid, etc. All the factors that can cause roller surface damage can be harmful to aluminum foil rolling. Because aluminum foil rolling roll surface finish is very high, slight gloss uneven will also affect its surface state. Regular cleaning of the rolling mill, keeping the rolling mill clean, ensuring the normal work of the roller cleaner, regular roll change, reasonable grinding, are the basic conditions to ensure the uniform surface of aluminum foil rolling.

3. wrinkle. Because of the serious bad shape, when the aluminum foil is rolled or expanded, wrinkle will be formed. Its essence is that the tension is not enough to flatten the foil surface. For the device with a tensile dimension of 20MPa, the shape of the foil surface shall not be greater than 30I, when greater than 30I, it is bound to wrinkle. Because the aluminum foil is often subjected to more tension than the subsequent processing, some in the rolling performance is only bad shape, including roller grinding is not correct, roll type is not correct, the incoming plate shape and adjust the plate shape is not correct.

4. The thickness difference. The thickness difference is difficult to control is a characteristic of aluminum foil rolling. 3% thickness difference may not be difficult in plate production, but it is very difficult in aluminum foil production. The reason is that the thickness is thin, and other microconditions can affect, such as temperature, oil film, oil and gas concentration, etc. Aluminum foil rolling a roll can reach hundreds of thousands of meters, rolling time up to 10h or so, with time extension, the thickness difference is easy to form, and the means of thickness adjustment only tension speed. All these factors have caused the difficulty of thickness control of aluminum foil rolling, so it needs many conditions to ensure that the thickness difference is really controlled within 3%, which is quite difficult.