Aluminum foil is thin sheets of metal stamping materials rolled by aluminum, and the pressing and print effect of it is similar to the pure silver foil. Because the aluminum has soft texture and good expansion as well as the shining surface, and the rolled thin sheet can be also used for printing. The Aluminum foil can be divided into different categories, for example, according to the thickness of aluminum foil, it can be divided into the heavy gauge foil, medium gauge foil and light gauge foil. The heavy gauge foil refers to the foil of which the thickness is 0.1～0.2 mm, the medium gauge foil is the foil, of which the thickness is 0．01 mm～0．1 mm, and light gauge foil usually refers to the foil of which the thickness is less than 0.0075 mm, sometimes, in the foreign country, when the thickness of the foil is less than 40l tm is called light gauge foil, and when the thickness of the foil is more than 40 btm, it is called the heavy gauge foil.
According to the shape of the aluminum foil, it can be divided into the rolled aluminum foil and flake aluminum foil. The aluminum foil processing wool is mostly supplied the rolled shape, and only in a small number of handicraft packing occasions, it will use the flake aluminum foil. According to the state of the aluminum foil, it can be divided in to the hard foil, semi-hard foil and soft foil. The hard foil refers to the foil that is rolled and haven’t been softened, the hard foil must be conducted degreased treatment before it is printed, pressed or coated , and it can be used directly if it is used for forming process. The semi-hard foil refers to the foil that the hardness of it is between the hard foil and the soft foil, which is usually used in forming process. The soft foil is the foil that has been rolled and fully annealed, it is soft, and there is no oil left on it, and it is now applied in the fields such as the packing, bonding and electrical material, and they all use the soft foil.