- All the empty cans painted inside are used to improve the corrosion resistance of metal packaging iron cans; at the same time, the electrochemical action of metal can dissolve a small amount of iron in the metal iron box.
- Production of stamping molding. That is to use a punch of a punching machine to punch a flat plate into a cylindrical die to deform the metal flat plate into a circular iron can. The diameter of the iron box formed after initial stamping can be reduced by applying a re-stamping process.
- Cut the iron sheet into a rectangular iron sheet, roll the blank into a cylindrical shape, and weld the joints at both ends longitudinally to form a cylindrical shape. One end of the cylinder and the round end cap are mechanically rolled and sealed, and the other end is loaded into the prepared can lid to form a packaged tin can, also called three-piece can.
Usually this three-piece can also needs to prevent rust on the outer surface, and still needs to be printed. Note when making three-piece cans: before the end folding process, the corners and nicks should be cut; during the soldering process, the soldering should be wiped with tin scraps, and after cooling, the can body is finished.