Can Production 101
The United States produces nearly 100 billion aluminum beverage cans a year. Lightweight, recyclable, and durable; aluminum cans are the dominate form of packaging for carbonated beverages, and have seen widespread use since the Adolph Coors Company first manufactured an aluminum beer can in 1958. Beverage companies have had 55 years to improve on the can production process. Here is a brief overview of how a typical beverage can is developed.
Forming the Body
Can production starts with a sheet of aluminum which is fed through a punch press which punches out 5.5 inch (14 cm) diameter disks called blanks. The left over material is collected and scrapped to be smelted back into aluminum ingots, while the blanks are fed into a machine called the draw and iron body maker. This machine initially bends and draws out the aluminum from the blank into the shape of a cup 3.5 inches (8.9 cm) in diameter. Depending on the process, the cup will have to be redrawn a second time, reducing the initial diameter but increasing the height. The cup is then pushed against three rings called ironing rings which stretch the cup walls smoothing the sides and thinning the aluminum walls, while yet another press gives the bottom of the can it’s characteristic inward shape. The entire process is finished in half a second and leaves the can with small ripples along the top called ears. Once the can is the right shape and size it is transferred to a trimmer, which removes the ears from the top of the can leaving a smooth and level edge.
Cleaning and Preparation
After the drawing and ironing stage, the cans are deposited on a conveyor belt which feeds them into a washer and dryer where the cans are subjected to a rigorous sterilizing and cleaning process. Once dry a varnish is applied to the bottom of the can to allow it to slide effectively across supermarket shelves. Meanwhile the insides of the cans receive another water based varnish that separates the aluminum from the beverage. This ensures that the carbonation won’t deteriorate the aluminum, and ensures the drink will not have a metal after taste.
The cans are now ready to be printed, and are fed through a multi-color rotation printing system that quickly inks the designs on to the surface of the can. The system also applies a final layer of varnish to the outside of the can to protect the ink. The cans are passed through an oven which instantly dries the ink and varnish before feeding them through a necker and flanger which gives the can its characteristic curved neck. The can is now ready to receive its pull tab cover further in the production process. Finally, the cans are tested for quality before being shipped to the beverage company to be filled, sealed, and shipped to consumers across the nation.