The two basic types of metal cans produced today are 2-piece cans and 3-piece cans. Another type of aluminium draw-and-iron can is the 1-piece aluminium can where no top end piece is required, which is used for aerosol and other compressed gas products.

Before the can bodies are formed, coatings are usually applied to the interior and exterior surfaces by roller onto the flat sheet of aluminium.

Interior coatings are applied to protect the can from corrosion by the contents and/or to protect the contents from being contaminated by metal dissolving within the can. Occasionally, pigmented interior coatings are applied to enhance the visual appearance of the inside of the can.

Exterior coatings are applied for decoration, to protect the can from corrosion, to protect the printed designs from marring or abrasion or to reduce friction on the bottom of the can to facilitate handling. Typical exterior coating operations are base coating, size coating, decorative ink and over varnish application, bottom coating, side seam stripe application and repair coating. Exterior coatings are usually applied using direct-roll coaters.

In the coating process, the steel sheets are fed to a conveyor by a sheet feeder. The sheets are transferred to the coater, where the coating is transferred from a tray to the roll coater by a series of rollers, then is applied to the sheets.

Most roller-applied coatings (except for printing inks and over varnishes) can be applied using the same coating equipment, and many facilities use the same equipment to apply a variety of coatings to can bodies, ends, crowns and closures, as well as decorative tins.