Many foods are stored in metal cans, and the packaging includes tea, moon cakes, candies, etc. However, the production methods of metal cans are different from ancient times to the present. Today, I will share this knowledge for everyone.
The traditional method of making metal cans is to first cut the iron sheet blank into squares, then roll the blank into a round (simplified) and then solder the formed longitudinal joint line to form a side seal, one end of the cylinder (ie The bottom of the metal can and the round end cap are mechanically formed into a flange and rolled and sealed (this is a double crimping seam) to form the body of the metal can; the other end is filled with the product and then the can is sealed Lid. Since this metal can is composed of three parts: the bottom, the body, and the lid, the three-piece metal can-making method has basically not changed much in the past 150 years. It is only the degree of automation and processing accuracy. In order to improve, in recent years, the weld of the side seal has been changed to fusion welding.
In the early 1970s, a new can-making principle appeared. According to this principle, the can body and the bottom of the can are an integral piece, which is punched by a round slab.
It is pressed into the product and then sealed. This is a two-piece can. This metal can has two forming methods: punching, thinning and drawing method (that is, punching and drawing method) and punching and then punching method (that is, deep drawing method, these The technology itself is not a new punching method. It has been used to make bullets and cans as early as World War I. The difference is the use of ultra-thin metal and the high production speed (annual production of hundreds of millions of stars) .