The main defects of aluminium foil jumbo roll are:

The main defects of aluminium foil jumbo roll are:

(1) Pinhole. Pinholes are the main defect of aluminium foil jumbo roll. In the raw material, on the roll, in the rolling oil, and even the dust in the air reaches about 6μm and enters the roll gap, it will cause pinholes. Therefore, it is impossible for 6μm aluminium foil jumbo roll to have no pinholes. It can only be evaluated by how much and its size. Due to the improvement of aluminium foil jumbo roll rolling conditions, especially the effective filtration of dust and rolling oil and the setting of convenient roll changing system, the number of pinholes in aluminium foil jumbo roll is more and more dependent on the metallurgical quality of raw materials and processing defects. It is difficult to find the corresponding relationship with the original defect when the defect of the raw material falls off. It is generally believed that pinholes are mainly related to gas content, inclusions, compounds and composition segregation. Effective aluminum liquid purification, filtration, and grain refinement can help reduce pinholes. Of course, the use of alloying and other means to improve the hardening characteristics of the material also helps to reduce pinholes. The pinholes of 6μm aluminium foil jumbo roll rolled from high-quality hot-rolled materials can be less than 100/㎡. When the casting and rolling materials are well purified, the pinholes of 6μm aluminium foil jumbo roll are below 200/㎡. In the aluminium foil jumbo roll rolling process, there are many other factors that cause pinholes, even catastrophic, and thousands of pinholes per square meter are not uncommon. Effective filtration of rolling oil, short-term replacement of rolls and dust-proof measures are all necessary conditions to reduce pinholes in aluminium foil jumbo roll, and the use of large rolling force and small tension rolling will also help to reduce pinholes.

(2) Roll mark, roll eye, uneven gloss. It is mainly the aluminium foil jumbo roll defect caused by the roll, which is divided into three types: point, line and surface. The most notable feature appears in three cycles. The main reasons for this defect are: incorrect grinding of the rolls; damage to the rolls by foreign objects: incoming defects imprinting the rolls; roll fatigue; impact between rolls, slippage, etc. All factors that can cause damage to the surface of the roll can cause harm to the rolling of aluminium foil jumbo roll. Because the surface finish of the aluminium foil jumbo roll rolling roll is very high, slight uneven gloss will also affect its surface condition. Regular cleaning of the rolling mill, keeping the rolling mill clean, ensuring the normal operation of the roll cleaner, regular roll change, and reasonable grinding are the basic conditions to ensure the uniform surface of the aluminium foil jumbo roll after rolling.