Three-Piece Can

A three piece can consist of three parts:
•Cylindrical shell (body)
•Top end
•Bottom end

Three-piece cans are mainly used for food, but may be used for some non-carbonated beverages, particularly fruit juices. Three-piece cans to be filled with dry food, e.g., milk powder, instant baby food, sweets or roasted nuts.

Three-piece welded food cans are only constructed from steel, as aluminum is not suitable for welding by this particular process. Tin-free steel is electrocoated with a layer of metallic chromium covered by a layer of chromium oxide.

Before the bodies are formed, coatings are usually applied to the interior and exterior surfaces with a roller onto the flat sheet.

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.

The wall of the can is rolled to form a cylinder and the seam (joint) is welded. In some types of three-piece cans, the side seam is crimped rather than welded or soldered.

For both food and drink cans, one end is then mechanically seamed on to the bottom of the can body. This end is commonly referred to as the maker’s end (ME). Where easy-open ends are fitted to three-piece cans, it is common practice for this end to be fitted at this point, leaving the plain end (non-easy-open) to be fitted after filling.

After the can is filled with the product mix the can is sealed with a tight mechanical structure - the so-called double seam. The double seam, in its final form and shape, consists of three layers of lid and two layers of body material.
Three-Piece Can