Use of tin cans dates back to the World War II; this is where large quantities of beer were shipped to the servicemen overseas. Since then, use of can has been commonly used primarily for filling beverages and selling food products before sale. The initial cans were made of steel but over time aluminum material was incorporated that prevents the galvanic reaction between the product and the can. The manufacturing process of a tin entails several steps that integrate together to form the final item. Here are the steps involved:
Cutting the Blank
Wall ironing and two-piece drawing is a conventional method of making cans that have been employed by most companies. The first step in the tin can manufacturing process is can maker machine cutting the blanks from the metal plate. Usually, this process begins with aluminum ingot that measures about 30 inches being rolled to form a thin sheet. The next step is to cut the thin sheet into circles called blanks that will make the body and the bottom of the can. During this process, about 12 to 14 percent of the sheet is wasted, but it can be used later as a scrap.
Redrawing the cup
The next step in the can production line is to redraw the cup. The small cup from the initial draw is moved to the second station where a sleeve precisely holds the cup, and the lower end is punched swiftly into the cup. The punch pushes this cup against three iron rings which stretch and thins the cup walls. Drawing and ironing operation happens under continuous punch stroke and takes a short period. Then there is another punch that presses the base of the cup making it bulge inside. The lower walls and the bottom should be made slightly thicker to increase the strength.
Trimming the ears
The process of ironing and drawing can leave a slightly curved at the top. These small ripples called ears that are unavoidable. Trimming is then done at the top end of the can to make the upper walls level and straight.
Cleaning and Decoration
After obtaining a smooth and shiny outer wall, there is no need any other finishing. The can is cleaned and then printed with labels. After this, the can is then decorated, and the upper top is slightly squeezed with the necking machine. Then it is then flanged outward at the top so that it can accommodate the lid.
A lid for the base is mostly of different material from the body. The inward bulge made at the bottom will help the can withstand pressure from the products inside. A lid should also be stronger and stiffer. The center of the top is usually stretched upward with a machine to create a rivet. The cans are then checked automatically for any leakages or cracks.
Filling and Seaming
After the can is checked, it is ready to be filled with the desired products. The can is held tightly as the beverage is poured in then the lid is added. The upper flange initially formed is then bent around and sealed.