Corrugated cardboard flute types: E, B, C and double wall

Corrugated cardboard consists of a fluted paper layer between two flat paper facings, and gets its strength from that flute. Flute types are named by letters: E flute is thin with a smooth surface, B is medium and C is thicker. Double wall (EB, BC) combines two flute layers for higher compression strength.

How does corrugated cardboard work?

The fluted layer behaves like an arch: it spreads the load from above sideways and absorbs impact. A taller flute gives more cushioning and stacking strength, but a less smooth surface for printing. Choosing a flute type is therefore a balance between protection and print quality.

Flute types

Choosing the right flute for your box

• If the product is light and the box is printed, a thin flute keeps the print surface smooth.
• If the carton is stacked on a pallet, double wall adds compression strength.
• If the product moves inside the box, adding void fill is often more effective than moving to a thicker flute.

Custom size and printing

For its corrugated cardboard boxes and sheets, Biyopak sets the thickness, density, dimensions and flute combination for each project and produces samples. A box that fits the product exactly reduces the need for internal void fill.

Completing the pack

Closing the carton with Protack® kraft paper tape and using cardboard edge protectors on pallet loads makes the pack paper from start to finish.