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May 6, 2021, 07:34 PM 36 read

Aluminium Foil Guide - How To Prevent Winkle, Pinhole, Roll Mark And Roll Hole


Aluminum foil is not only a safe food wrapping material; it often preserves food while keeping it fresh and heat-free. They can make paper and plastic more useful and stronger. Do you know how to protect the aluminium foil? For example, to prevent the winkle, pinhole, roll mark and roll hole of aluminium foil, if you are interested, keep reading.

  Wrinkle Of Aluminium Foil The longitudinal or transverse wrinkle on the surface of aluminum foil coil becomes wrinkle. Due to the serious bad shape of the plate, the aluminum foil is wrinkled during coiling or unfolding, which means that the tension is not enough to flatten the box surface. For the device with a tension of 20MPa, the shape of the box surface should not be greater than 301. When it is greater than 301, it is bound to wrinkle.

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  Because the tension of aluminum box during rolling is often greater than that during subsequent processing, some aluminum foils with poor shape during rolling show wrinkling after slitting or annealing. The main causes of wrinkling are poor flatness control, including incorrect grinding of roll, unreasonable control of roll profile, unreasonable control of rolling and slitting process parameters, poor incoming flatness and incorrect adjustment of flatness, and insufficient precision of sleeve or tube core.   The small, longitudinal or oblique local convex, one or several smooth groove tips on the surface of aluminum foil are called wrinkles. The main causes of wrinkles are as follows: too much reduction, resulting in uneven deformation during rolling or insufficient tension during coiling; Improper roll profile control or low rolling pressure; The thickness of the blank is not uniform, the shape is not good or there are shear waves; The accuracy of coiling shaft is not enough and the sleeve is not round; The pressure of flattening roller is not controlled properly.   Pinhole Of Aluminium Foil The irregular holes on the surface of aluminum foil are called pinholes. With the thickness decreasing, the number of pinholes increases, which is one of the main defects of foil. The dust in billet, roll, rolling oil and even air reaches 6 μ It is impossible for 65m aluminum foil to have no pinhole, so it can only be evaluated by the number and size.   With the improvement of the installation level of aluminum foil equipment, the rolling conditions of aluminum foil have been improved, especially the effective dust-proof and rolling oil filtration and quick roll changing system, so that the number and size of pinholes in aluminum box increasingly depend on the metallurgical quality and processing defects of billet. Because pinholes are often the shedding of billet defects, it is difficult to find the corresponding relationship with the original defects. It is generally believed that the pinhole is mainly related to gas content, inclusion, compound and component segregation.   Effective purification, filtration and grain refinement are helpful to reduce pinholes. It is also helpful to reduce pinholes to improve the hardening properties of the material by means of alloying. 6 times of rolling high quality aluminum tip billet μ M aluminum foil pinholes can be in 100 / m ² following. In the process of aluminum foil rolling, there are many other factors causing pinholes, even catastrophic. Thousands of pinholes per square meter are not uncommon. Strengthen the filtration of rolling oil   Short term roll replacement and dust prevention measures are necessary to reduce the pinhole of aluminum foil; Large rolling force and small tension rolling will also help to reduce pinholes.   Roll Mark & Roll Hole Of Aluminum Foil Roll marks and roll holes are mainly caused by aluminum box defects caused by rolls. Roll marks are the marks that appear in periodic arrangement during aluminum foil rolling; The roll hole is the periodic arrangement of holes on the surface of aluminum box, some of which are all transparent, some of which are reticular, and their size is generally larger than the pinhole.   The most obvious feature of these two defects is the periodic appearance. The main reasons for these two defects are: incorrect roller grinding; The roll is damaged by foreign objects; The roller is damaged by the defect of incoming material; Roll fatigue; Collision and slipping between rolls. All the factors that can cause the surface damage of the roll are harmful to the aluminum foil rolling. Because the aluminum box rolling roll surface finish is very high, slight uneven gloss will also affect its surface state.   Regular cleaning of the rolling mill, keeping the rolling mill clean, ensuring the normal operation of the roller cleaner, regular roll change and reasonable roll grinding are the basic conditions to ensure the uniform surface of aluminum foil after rolling.  

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