Canning and Fish Packaging Technology

Unit 13 - Paper and Board

13.1.5.2.3.Types of flutes
There are four types of flute in general use designated as A B C and E. They are distinguished on the basis of flute height and number of corrugations per unit length.

Flute form	Number of Corrugation/meter (mm)	Corrugation height
A	105-125	4.5-4.7
B	150-185	2.1-2.9
C	120-145	3.5-3.7
E	290-320	1.1-1.2

An important feature of the corrugated board is that it combines stiffness and or rigidity-with the cushioning ability. This combination of properties is as a result of its structure which is similar to truss structure of a bridge. In this structure based on the principle that when two strong surfaces (liners in this case) separated and anchored by a third (fluting medium), resulting in strength that is greater than the sum of the strengths of individual constituents.

Stiffness and rigidity are the function of number of corrugations per unit length. They increase with number; cushioning ability is a function of height of the corrugations. Different flute forms combine these properties in different proportions.