Surface quality is one of the important quality indicators of high-quality aluminum foil. Since the rolling of double-sheet aluminum foil is characterized by rolling twice on the finishing mill, two surface qualities of "smooth" and "dark" are formed. In double rolling, there are two uncoilers on the entrance side of the finishing mill to roll the two workpieces together, and there is a recoiler that overlaps and then rolls on the finishing mill. After rolling is completed, the double sheets are cut into single sheets by a slitting machine. After the aluminum foil is separated, the surface in contact with the roller during finishing rolling becomes a shiny bright surface, while the surface where the two aluminum foils are combined together becomes a dark surface due to free deformation and large surface roughness.
The dark side of double rolling is prone to "bright spot" defects and uneven color (often called the yin and yang side). Highlight defects are usually caused by unreasonable physical and chemical indicators of rolling oil and double oil, uneven surface roughness of work rolls, uneven local deformation of aluminum foil during double rolling, and inconsistent color and brightness of local dark surfaces. with matrix. Defects on the yin and yang surfaces appear as band-like stripes with uneven gloss on the dark side of the double compound, which tend to decrease after annealing. The reason is caused by the partial lack of double compound oil. The above two defects are unique to aluminum foil rolling; In addition, due to the uneven structure and grain size of the billet, small uneven strip defects are often caused on the dark side, which affects the improvement of aluminum foil quality; long white band defects often appear on the smooth surface of aluminum foil , is directly related to the uniformity of the roll grinding roughness, the local cooling and lubrication capabilities of the rolling oil, the material of the roll cleaner and the size of the contact pressure. Improving the structure of the roller cleaner and increasing the surface quality of the rollers (support rollers and work rollers) are important measures to produce high-quality aluminum foil surfaces.
Aluminum foil 1235O for flexible packaging is mainly used for packaging food, beverages, cooked food and other foods, which has greatly improved the mechanized production level of the food and beverage industry. With the improvement of people's living standards and the acceleration of the pace of life, food supply methods have changed, and there are more and more convenience foods with long shelf life. Since the shelf life of aluminum foil and plastic composite bags is about 5 times longer than that of plastic bags of the same thickness, the demand for aluminum foil for flexible packaging is growing rapidly.
Appearance quality of aluminum foil for flexible packaging: The cross-section of the aluminum foil is neat and free of defects such as cracks, towers, loose rolls, concave and convex, and concave and convex.
Surface quality of aluminum foil for flexible packaging:
A. There are no bright spots, rolling marks or black lines on the surface of the aluminum foil.
B. The surface of the aluminum foil is smooth.
C. The surface of the aluminum foil is clean and free of oil, corrosion marks and scratches.
