Food cans and beverage cans can be divided into two-piece cans and three-piece cans according to the can-type structure. The two-piece can is a piece of can bottom, and the can lid is one piece; the three-piece can is composed of three parts: the can body, the bottom of the can and the can lid. The two-piece cans are in the form of punching and cupping (can height is less than diameter), multi-stage punching and canning (referred to as DR tank, punched twice or more, tank height is equivalent to diameter) and punching and drawing cans (referred to as DI tanks, after many times) Punching and thin-wall drawing, the height of the tank is larger than the diameter, and the wall thickness of the tank body is smaller than the wall thickness of the tank bottom).
The three-piece cans are in the form of round cans and shaped cans (such as oval cans, square cans, trapezoidal cans, horseshoe cans, etc.). The three-piece cans can be divided into tin welding cans, electric resistance welding cans and bonding cans according to the seam pattern of the can body; according to the inner wall condition of the can, it can be divided into plain iron cans (with tin-plated thin plates, no coating on the inner wall), paint cans Some paint cans (usually the can body is coated with strip coating) and high tin cans (referred to as HTF cans, which are full-coat cans with a pure tin strip in the tank along the joint).
The can lids of the two-piece can and the three-piece can have both a common cover and an easy open cover. The easy open can is stamped on the outer surface of the cover and riveted with a pull ring or snap button. When opened, the cover can be pulled or opened along the score. Sealing glue is required on the edges of various can lid bottoms, that is, sealing glue (such as ammonia glue made of natural rubber or synthetic rubber), baked or cured at room temperature. The combination of the can lid, the bottom of the can and the can body is sealed by a roller on the can sealing machine to form a double bead.