The traditional method of making metal packaging cans is to first cut the iron sheet flat blank into long blocks, then roll the blank into a cylinder (i.e. cylinder body), and solder the longitudinal joint lines formed to form a side seal. One end of the cylinder (i.e. can bottom) and the circular end cap are mechanically flanged and rolled to seal (i.e. double rolled edge seam), thus forming the can body; The other end is sealed with a lid after the product is loaded. Due to the fact that a container consists of a bottom, body, and lid, it is called a three piece can. This canning method has remained largely unchanged for over 150 years, with significant improvements in automation and processing accuracy. In recent years, the welding seam of the side seal has been replaced with fusion welding.
In the early 1970s, a new canning principle emerged. According to this principle, the can body and bottom are a whole, stamped from a circular flat plate blank, and sealed after being loaded into the product, which is called a two-piece can. There are two molding methods for this type of can: stamping thinning stretching method (i.e. punching and pulling method) and stamping re stamping method (i.e. deep drawing method). These technologies themselves are not new. The punching and pulling method has been used to manufacture shell casings since World War I, while canning differs from it in that it uses ultra-thin metal and has a high production speed (with an annual output of hundreds of millions of shells)
Cn
English
