Box Structure

Corrugated fibreboard is made up of linerboard and the corrugated medium. The flat linerboard is adhered to the "wavy", fluted medium to form the corrugated board. There are 3 main types of corrugated board.

1. Singleface
Singleface consists of one liner adhered to one corrugated medium and is generally used as wrapping material, padding or for interior packaging.

2. Single Wall
Single Wall board consists of corrugated medium adhered to both an inside and an outside liner. The outside liner is generally smoother than the inside liner, which is more rippled. Commonly used to convert into boxes or other packaging components.

3. Double Wall
Double Wall consists of three liners with two corrugated mediums adhered between them. As in Single Wall, the outside liner is smoother than the inside liner. Also, the outside corrugated medium is more compact than the inside corrugated medium. Double Wall is used for packaging heavy items that may require increased protection and box rigidity.

Flutes - The "waves" on the corrugated medium are called flutes which, depending on the direction and the distance between the flutes, can provide stacking strength and/or cushioning. There are 3 standard flute shapes or profiles, which are distinguished by the distance between them.

Flute	Profile	Flutes/Foot	Thickness	Advantage and Uses
C		41	4mm	- superior stacking strength - commonly used for transit cartons
B		49	3mm	- good puncture resistance - provides a good surface for printing - commonly used for die-cut boxes and transit cartons
E		95	2mm	- lightweight - excellent print surface - easily folded - alternative to paperboard - commonly used for die-cut boxes and retail packaging