Corrugated cardboard sheets are known for their thickness and strength, they are used as separators, for decorations, signs, arts, protection of the product in packaging boxes, making a corrugated box, and thus have versatile uses. They are best used for the protection of the product in shipping, moving, and storage.
Below is the History of Cardboard and Corrugated Cardboard:
Corrugated sheets are also called Corrugated Pads. Corrugated sheets are made of corrugated fiberboard, which has two smooth, flat outer kraft paper layers called liners, and in between is a wavy, fluted corrugated layer of thick kraft paper called flute.
There are different types of corrugated sheets. Corrugated cardboard sheets are made of different types of flutes. These different types of corrugated flute sheets are used to make Single Wall Corrugated Cardboard Sheet, Double Wall Corrugated Cardboard Sheet, Triple-wall Corrugated Cardboard Sheet, and Four Wall Corrugated Cardboard Sheet.
Corrugated sheets are available in the market of different flutes. Corrugated cardboard flute is a term used to determine the thickness of the corrugated board. Flute type depends on the number of wavy corrugated flutes per linear foot. Corrugated cardboard sheets that are made of different flutes are A, B, C, E, F, D, N, G, T, and R.
Below is the Table of Different Types Of Corrugated Cardboard Flutes, Thickness, Height, and Number of Flutes Per Linear Foot:
Flute Type |
Flute Height/ Thick-ness Inches |
Flute Height/ Thick-ness Milli-meter |
Number of Flutes Per Linear Foot |
A Flute |
3/16” or 0.25 inches |
4.8 mm |
33-36 |
B Flute |
1/8” or 0.125 inches |
3.2mm |
49 |
C Flute |
5/32” or 0.17 inches |
4mm |
38-39 |
E Flute |
1/16” or 0.06 inches |
1.6mm |
90 |
F Flute |
1/32” or 0.031 inches |
0.8mm |
125 |
D Flute |
5/64” or 0.22 inches |
2mm |
63 |
N Flute |
1/64” or 0.02 inches |
0.5mm |
190-210 |
G Flute |
1/32” or 0.031 inches |
0.6mm |
170-190 |
T Flute |
1/64” or 0.046 inches |
1.7mm |
72 |
R Flute |
1/6” or 0.090 inches |
3mm |
60 |
Below is the Image of Different Flute Types of Corrugated Cardboard Sheets:
For more information on different types of Flutes, Edge Crush Test and Mullen Test please visit the How to Choose the Right Flute Type in Corrugated Boxes blog
Single-face corrugated sheets have a single flat, smooth kraft paper sheet called a liner, and on top of it is a wavy, fluted corrugated layer of thick kraft paper called a flute.
Below is the Image of the Construction of Single Face Corrugated Cardboard Sheets:
Below is the Image of Different Flute Types available in Single Face Corrugated Cardboard Sheets:
Below are the Uses of Single Face Corrugated Sheets:
Single-wall corrugated sheets are made of three kraft paperboard layers. The top and bottom layers are made of flat, smooth kraft paper sheets called liners, and in the middle, there's a wavy, fluted corrugated kraft layer called flutes. As the flutes are sandwiched between the flat layers, they form a strong corrugated single-wall sheet. Single wall sheets thickness and quality depend on Basis Weight. The basis weight of any paper is measured in Pounds(lbs), Points, Cover, or GSM. In the USA paperweight is measured in Pounds.
The most common single-wall corrugated sheets used in the market are flute B, flute C and flute E. To know more about the difference between 200 lb Single Wall Corrugated Sheets and 32 ECT please visit the 200# and 32 ECT Boxes blog
Below is the Image of Construction of Single Wall Corrugated Cardboard Sheets:
Below is the Image of Different Flute Types available in Single Wall Corrugated Cardboard Sheets:
Below is the Table of Different Types of Single Wall Corrugated Cardboard Sheets that are used by Packaging Industry with its Weight-bearing Capacity:
MOST COMMON USED SINGLE WALL FLUTE TYPES |
COMMON ECT RATING (EDGE CRUSH TEST) |
COMMON MULLEN TEST (BURST TEST) |
APPROXIMATE WEIGHT CAPACITY |
B, C |
ECT 23 |
125 psi |
15/20 pounds |
B, C |
ECT 26 |
150 psi |
25/35 pounds |
B, C |
ECT 29 |
175 psi |
45/50 pounds |
B, C, A, E |
ECT 32 |
200 psi |
55/65 pounds |
B, C, A |
ECT 40 |
225 psi |
75/80 pounds |
B, C, A |
ECT 44 |
300 psi |
85/90 pounds |
B, C, A |
ECT 55 |
326 psi |
115/120 pounds |
Double wall corrugated sheets are made of five kraft paperboard sheets. It has five paper sheet layers, where the first layer is a smooth flat kraft paper liner, the second layer is a wavy fluted corrugated kraft paper layer, the third layer is again smooth flat kraft paper liner, the fourth layer is again wavy fluted kraft paper corrugated layer, and the last fifth layer is again smooth flat kraft paper liner.
Below is the Image of the Construction of Double Wall Corrugated Cardboard Sheets:
Below are the Uses of Double Wall Corrugated Cardboard Sheets:
Below is the Table of Different Types of Double Wall Corrugated Cardboard Sheets for the product by Weight-bearing Capacity:
POSSIBLE DOUBLE WALL FLUTE TYPES |
COMMON ECT RATING (EDGE CRUSH TEST) |
COMMON MULLEN TEST (BURST TEST) |
APPROXIMATE WEIGHT CAPACITY |
BC, AC |
ECT 44-48 |
275 psi |
95/100 pounds |
BC, EB |
ECT48 |
275 psi |
275 pounds |
BC, AC |
ECT 51-55 |
350 psi |
115/120 pounds |
BC, AC |
ECT 61-65 |
400 psi |
135/140 pounds |
BC, AC |
ECT 71-75 |
500 psi |
155/160 pounds |
BC, AC |
ECT 82 |
660 psi |
180/185 pounds |
Triple wall corrugated sheets are made of seven kraft paperboard sheets. It is also called Septuple Corrugated Cardboard Sheets. It has seven kraft paper sheet layers, where the first layer is smooth flat kraft paper liner, the second layer is a wavy fluted corrugated kraft paper layer, the third layer is again smooth flat kraft paper liner, the fourth layer is again wavy fluted corrugated kraft paper layer, the fifth layer is again smooth flat kraft paper liner, the sixth layer is again wavy fluted corrugated kraft layer and seventh(last) layer is smooth flat kraft paper liner.
Below is the Image of Construction of Triple Wall Corrugated Cardboard Sheets:
Below are the Uses of Triple Wall Corrugated Cardboard Sheets:
Below is the Table of Different Types of Triple Wall Corrugated Cardboard Sheets for the product by Weight-bearing Capacity:
POSSIBLE TRIPLE WALL FLUTE TYPES |
COMMON ECT RATING (EDGE CRUSH TEST) |
COMMON MULLEN TEST (BURST TEST) |
APPROXIMATE WEIGHT CAPACITY |
BAC, AAC |
ECT 67 |
700 psi |
230/240 pounds |
BAC, AAC |
ECT 80 |
900 psi |
250/260 pounds |
BAC, AAC, CAC |
ECT 90 |
1100 psi |
270/1100 pounds |
BAC, AAC, CAC |
ECT 112 |
1300 psi |
290/1300 pounds |
Four-wall corrugated sheets are made of nine kraft paperboard sheets. It has nine paper sheets, where the first layer is smooth flat kraft paper liner, the second layer is a wavy fluted corrugated kraft paper layer, the third layer is again smooth flat kraft paper liner, the fourth layer is again wavy fluted corrugated kraft paper layer, the fifth layer is again smooth flat kraft paper liner, the sixth layer is again wavy fluted corrugated kraft paper layer, the seventh layer is again smooth flat kraft paper liner, the eight layer is wavy fluted corrugated kraft paper layer and the last ninth layer is again smooth, flat kraft paper liner. They can also be made by gluing two double wall corrugated sheets or gluing four single wall corrugated sheets.
Below is the Image of Construction of Four Wall Corrugated Cardboard Sheets:
Below are the Uses of Four Wall Corrugated Cardboard Sheets:
Five-wall corrugated sheets can be made by gluing double wall corrugated sheets with triple wall corrugated sheets or by gluing five single wall corrugated sheets.
Below is the Image of Construction of Five Wall Corrugated Cardboard Sheets:
Below are the Uses of Five Wall Corrugated Cardboard Sheets:
Below is the Image of the Difference between Single Face, Single Wall, Double Wall, Triple Wall, Four Wall & Five Wall Corrugated Sheets: