All empty cans with internal paint are used to improve the corrosion resistance of metal packaging tin can containers; at the same time, the electrochemical action of the metal can dissolve a small amount of iron in the metal tin box.
Make stamping. That is, use a punch of the stamping machine to punch a flat plate into a cylindrical die to deform the metal flat plate into a round tin can. The diameter of the tin box formed after the initial stamping can be reduced by applying the re-stamping process.
Cut the tin plate into a rectangular iron sheet, roll the blank into a cylindrical shape, and solder the joints at both ends longitudinally to form a cylinder. One end of the cylinder and the circular end cap are mechanically rolled and sealed, and the other end is loaded with the prepared can lid to form a packaging tinplate can. The container is divided into three parts: the can body, the can lid, and the can bottom, so it is called a three-piece can. Generally, iron cans use three-piece cans, while aluminum cans use two-piece can technology. The patch uses offset printing technology. This type of three-piece iron can is not easy to hold candles. It is easy to leak. If you want to use it, it is recommended to apply glue to prevent wax leakage. Usually, this kind of three-piece can also needs to prevent rust on the outer surface, and printing is still required. When making three-piece cans, pay attention to: before the end folding process, the corners and notches should be cut; during the soldering process, the soldering should be wiped with tin chips, and the can body should be flanging after cooling.
In addition, the manufacturing requirements of punched iron cans: for dry beverage cans, the outer surface coating, printing performance, inner surface coating, flange forming and closing of the open end are also required. For food iron boxes, the outer surface coating, flange forming of the open end, barrel corrugation and inner surface coating are carried out during the cleaning process, or the lower end of the iron box is made of pre-coated sheet material on a multi-die press. The can cover is pressed with corrugated reinforcement ribs to bear internal and external pressures.
Environmental protection requirements for packaging tin cans: When tin cans exist in the environment, they can be naturally oxidized and return to their original iron oxide state, returning to nature. Therefore, the pile of waste tin boxes can be decomposed over time and will not remain to cause environmental pollution. At the same time, the production of tin cans does not require cutting down trees, which will not destroy the ecological balance and meet international environmental protection product requirements.
