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. The flutes are made of fiberboard, the same as the linerboard, and provide corrugated sheets with strength, cushion, and compression resisting qualities. This can also be used for custom print. Board strength will vary depending on the various board and medium combinations.
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. Corrugated board can be manufactured with different flute profiles. The Larger the flute, the greater the vertical compression strength and cushioning. Smaller flutes provide enhanced structural and print for use in retail packaging.
There are 3 standard flute shapes or profiles, which are distinguished by the distance between them.