Types of Cans
Cans are classified into;
- 1. 3 piece cans and 2 piece cans, depending on the structure.
- 2. Aluminum cans and steel cans, depending the material.
- 3. Pressurized cans and vacuum cans, depending on the degree of internal pressure.
2 Piece Cans and 3 Piece Cans
Major cans are classified into two types: 3-piece cans consisting of three components of (1) a bottom lid, (2) a cylindrical body and (3) a top lid (a lid with a lip [an opening] for a beverage can), and 2-piece cans consisting of two components of (1) a body integrated with a bottom lid and (2) a lid with a lip (an opening).
A technique called double seaming is used to attach the can body and can lids (top and bottom) and the contents are protected from external contamination. 3-piece cans are made of a rectangular sheet rolled into a cylindrical body and there are two seaming methods of soldering and electric welding.
Welded cans dominate the market while soldered cans have almost all disappeared from the market. 2-piece cans are further classified depending on their body processing method; drawn cans (drawn cans, draw and redraw cans [DRD cans]), DWI cans (draw and wall ironing cans) and TULC (stretch-draw-ironing cans).
|Structure||Names of Cans||Forming and Joining Methods||Major Metal Materials|
|2 Piece Cans
|Draw Cans (DRD: Draw and Redraw Can)||Draw (and Redraw)||Steel, Aluminum|
|DWI Cans (Draw and Wall Ironing)||Draw and Wall Ironing||Aluminum, Steel|
|TULC||Stretch, Draw and Ironing||Aluminum, Steel|
|3 Piece Cans||Soldered Cans||Soldering||Steel|
Aluminum Cans and Steel Cans
Aluminum and steel are used as the materials for cans. Cans are classified into either aluminum or steel, depending by the can-body (a cylindrical portion) material. Aluminum cans include aTULC (aluminum TULC), ADWI (aluminum DWI) and DRD cans. Steel cans include TULC, SDWI (steel DWI), DRD, welded and soldered cans. Aluminum and steel cans are grouped as shown in the following figure: