{"id":3417,"date":"2025-10-08T13:37:10","date_gmt":"2025-10-08T11:37:10","guid":{"rendered":""},"modified":"2026-03-27T22:43:30","modified_gmt":"2026-03-27T21:43:30","slug":"corrugated-cardboard","status":"publish","type":"page","link":"https:\/\/etykietynarolce.eu\/en\/knowledge-zone\/corrugated-cardboard\/","title":{"rendered":"Corrugated cardboard"},"content":{"rendered":"\n

Corrugated board \u2013 structure and why flute direction matters<\/h1>\n\n\n\n
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Structure and properties<\/h2>\n\n\n\n

Corrugated board consists of two or more layers. It is typically a brown material made, among other things, from cellulose pulp. Moreover, at least one layer has a \u201czig-zag\u201d (accordion-like) shape, so the material gains elasticity. As a result, corrugated board stays relatively light, yet it also remains very strong. Additionally, it supports many areas of industry and trade, therefore it has become a common packaging material.<\/p>\n\n\n\n

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A brief history of the material<\/h2>\n\n\n\n

The first attempts to produce corrugated paper took place in England in 1856. Edward G. Healy and Edward E. Allen used a simple machine that created wavy paper with two grooved rollers. At that time, the material was not yet linked to packaging, because people used it as a filler or stiffener for clothing, including hats.<\/p>\n\n\n\n

Later, in 1874, the American Olivier Long introduced an important change: he glued the fluted paper to a smooth sheet. In this way, a two-layer board appeared, and consequently it strongly supported the growth of the packaging industry<\/mark><\/a>.<\/p>\n\n\n\n

Production process: corrugator and fluting<\/h2>\n\n\n\n

Corrugated board is produced on a machine called a corrugator. Moreover, this line is unusually long, because it can reach up to 150 meters. The process alternates fluted layers with flat paper layers. The fluted layer is formed by corrugating rolls, often described as \u201cfluting\u201d, which give the paper the required shape and flute type.<\/p>\n\n\n\n

Starch glue and building additional layers<\/h2>\n\n\n\n

A starch-based glue bonds the fluted layer to the flat layer, called the liner. After this step, the first two layers create the initial board structure. Furthermore, manufacturers can repeat the process, therefore they can produce boards with different stiffness and strength levels.<\/p>\n\n\n\n

Flute direction and creasing<\/h2>\n\n\n\n

When you look at corrugated board, you can see channels running in one direction and parallel to each other. This is the flute. Why does it matter? Because it affects how a package folds and, at the same time, how strong it stays. In most cases, the key point is which panel edge the flute runs parallel to.<\/p>\n\n\n\n

In practice, production uses a die-cutting tool that cuts the packaging or a sleeve. The die includes crease lines that mark the fold. Moreover, crease rules have rounded ends, so they compress the board instead of cutting it.<\/p>\n\n\n\n

Therefore, matching flute direction is crucial. If the flute runs parallel to the crease lines on the die, folding microflute can become difficult. For this reason, when ordering board, it is worth indicating which creases are most important, so the packaging folds smoothly. As a result, you avoid production issues and achieve a clean final look.<\/p>\n\n\n\n

Corrugated board structure \u2013 types and applications<\/h1>\n\n\n\n
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Corrugated board comes in many variants, from the simplest two-layer board to more advanced constructions with up to seven layers. Each type has its own characteristics and applications, depending on strength and printability. Therefore, below you will find a description of the most common solutions.<\/p>\n\n\n\n

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2-ply corrugated board<\/h2>\n\n\n\n

Two-ply corrugated board is the simplest construction, consisting of two elements: a smooth outer layer (often called the facing or liner) and an inner fluted layer shaped like an \u201caccordion\u201d. This fluting gives the material its resilience. Moreover, the smooth liners provide stiffness, durability and the possibility of offset printing.<\/p>\n\n\n\n