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, (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, (1) a body integrated with a bottom lid and (2) a lid with a lip (an opening).
Each component is attached by seaming so that the can-body and can-lids (top and bottom) are connected. Cans are sealed by seaming so to isolate their interior from the outside environment. 3 piece cans are further classified depending on the body joining method (rolling and joining a rectangular flat plate into a cylindrical body) into welded cans (welding by thermal bonding) and soldered cans (bonding by soldering).
Welded cans dominate the market while soldered have almost all disappeared from the market. 2 piece cans are further classified depending on their body forming 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) |
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 |
| Welded Cans | Welding | 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:
