The cigarette inner packaging foil is mainly used as the inner lining paper of the cigarette box after being compounded with the paper. The aluminum foil paper in the cigarette case has two main functions: one is to preserve the fragrance, the other is to prevent mildew.
It is usually thin gauge aluminum foil with a thickness of 0.0063mm-0.0075mm, and aluminum foil with a thickness of 0.0055mm or less is called ultra-thin aluminum foil. The chosen alloys are 8079 and 1235 aluminum. How to ensure its surface quality?
The production of high-quality aluminium foil begins with the casting of rolled billets. Blanks are the basis for foil production and are a prerequisite for high quality and low cost. The metallurgical quality, shape and surface quality of the aluminum billet have an important impact on the production of aluminum foil.
As the thickness of aluminum foil decreases, the rolling process becomes more difficult, and the number of aluminum foil cracks, broken strips, and pinholes increases. The production of high-quality 0.005~0.006mm aluminum foil puts forward more stringent requirements for the hydrogen content of the blank, the content of non-metallic inclusions and the grain size index.
During the casting process, the optimum grain size is controlled, which has a decisive influence on the processability and surface appearance of the foil during rolling and finishing. A first-order equiaxed grain size is required.
The surface of the rolled billet shall be free from cracks, scratches, metal and non-metallic indentations, oil spots and other contaminants. In order to make the surface clean, eliminate the segregation layer, and ensure the smoothness of the rolling surface, the ingot used for processing aluminum foil must be milled.
The rolling mill is equipped with an AGC thickness online measurement and adjustment system to obtain precise dimensional tolerances. The chemical composition of the aluminum foil blank must be strictly controlled within the specified range, because its changes will have a great impact on the accuracy of the X-ray thickness gauge.
The rolling of aluminum foil generally starts from a cold-rolled billet with a thickness of 0.3 to 0.6 mm. After rough, medium and finish rolling to a foil of 5 to 20 μm, 5 to 6 passes are required, and the processing rate of each pass is 50 to 60%. The last pass needs to be double-rolled.
The most important aspect of aluminum foil rolling is shape control. Because the aluminum foil is very thin, if the plate shape is not good, the tension cannot be uniformly applied to the width direction during rolling, causing strip breakage, folding or wrinkling of the aluminum foil.
As a big experienced aluminum foil manufacturer, Haomei Aluminum’s 8079 and 1235 aluminum get high praise from customers worldwide. Welcome leave message below to inquire what you need.