There are mainly two types of end can used in the packaging industry: 2-piece and 3-piece tin cans.
2-Piece Tin Cans
Cup Blanking and Drawing – A press produces cups from coils of steel or aluminum.
Ironing and Doming – The cups are then subjected to a sequence of rings. This process irons out the cans to form the bottom domes.
Trimming – The cans spin while a cutting device trims the cans to length.
Cleaning – The trimmed cans undergo several cleaning processes.
Printing and Varnishing – The cans are now rolled against a cylinder for printing and varnishing.
Bottom Varnishing – The cans pass an applicator for bottom varnishing.
Baking – The varnished cans then wind through a conveying system inside an oven for drying and setting of lithography.
Inside Spraying – The application of a compounded protective coating inside the cans follows.
Baking – The next baking process comes next to cure the inside coating.
Necking – The necks of the cans are reduced so that they will fit the size of the can end.
Flanging – Flanges are formed on the cans’ rims for double seaming in the future using a tin can sealing machine.
Testing – Each of the produced cans are tested for leakages.
3-Piece Tin Cans
Shearing – A shear press cuts a large metal coil into sheets.
Coating – A protective coating is applied onto the metal sheets which are cured after.
Printing – The manufacturer decorates the sheets according to the customer’s preferences.
Varnishing – The decorated sheets undergo varnishing before curing.
Slitting – The body sheets are cut into individual blanks which are later formed into tin cans.
Scroll Shearing – A device cuts the body blanks into smaller scroll sheets.
End Forming – Stamping of ends from the smaller scroll sheets follows. The finished products are packed and delivered to customers and fabricating plants.
Body Forming – A bodymaker forms the body blanks into cylinders then joins the side seams through soldering, cementing, or welding.
Flanging – The cylinders from the previous process enter a flanger. The flanger rolls the metals on both of the cylinders’ ends to form flanges. Similar to the 2-piece cans, these flanges are created for double seaming purposes.
Double Seaming – An end of the can, either the top or the bottom end, depending on the customer’s specifications, is connected to the can through double seaming.
Spray Coating – The placement of a final coating on each can’s interior surface follows. This coating serves as the can’s protection from rust and corrosion.
Baking – The applied interior coating undergoes baking and curing processes through an oven. This oven is a funnel type one in which the operator must control the time-temperature values carefully.
