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Corrugated Board – Probably the World’s Most Widely Used Technical Lightweight Material
Corrugated board is more than just “cardboard with flutes”: as a sandwich structure, it separates load-bearing facings with a lightweight, shear-resistant core. Learn how the load-bearing principle works and why corrugating rolls are central to its manufacture.
Corrugated board looks simple at first glance: two flat layers of paper with a flute in between. Yet it is precisely this “fluted construction” that makes corrugated board simultaneously lightweight and strong – and is one of the key reasons why it is so successful as transport packaging worldwide.
Sandwich Structure: Why the Construction of Corrugated Board Matters
From a technical perspective, corrugated board is best understood as a sandwich structure: a lightweight core keeps two load-bearing facing layers (liners) apart. Mechanically, this construction efficiently increases the geometrical moment of inertia by separating the outer layers. It therefore follows the same principle as high-performance materials used in aerospace engineering, except that the raw material is paper with layer-by-layer precisely tuned properties.
There is a clear division of roles between the layers under bending the board:
- The face papers (liners) carry the tensile and compressive forces
- The fluting paper (fluting) primarily absorbs shear forces and ensures the facing layers remain separated.
The “lightweight leverage” principle means: the greater the distance between the load-bearing facings, the higher the bending stiffness at low weight. This principle is often compared to the double-T (I-beam) in structural steel engineering.
In corrugated board, the face papers form the load-bearing outer layers, while the flute(s) form the core. Corrugated board owes its great commercial success specifically to the ability to form the flutes, and thus the core, very efficiently by corrugating a paper web.
The development of corrugated board began in 1856, when Healey and Allen first patented corrugated paper for reinforcing cylinders in tall hats. In 1871, Albert L. Jones patented the use of this corrugated paper as packaging material for fragile goods. In 1874, Oliver Long patented the decisive sandwich structure of fluting and liners, laying the foundation for modern corrugated board. In 1881/82, Robert H. Thompson finally received the patent for “SingleWallBoard” and demonstrated for the first time an industrially driven mechanical production process:
The patent drawing clearly shows in its upper section the processing into what is today known as “single-faced corrugated board” and thus what was probably the first Single Facer. It also depicts the first set of corrugating rolls. Furthermore, the illustration shows the further processing into “single-wall corrugated board” and thus the addition of the second facing, which produces the desired “board effect”. Only this step completed the sandwich construction with all its associated advantages.
Applied to corrugated board, the flute is lightweight but adds height to the material cross-section through its geometry. The facing layers are spaced far apart, making the structure highly efficient under bending. Load-bearing packaging walls can thus be designed with minimal material usage.
Due to its construction and material properties, corrugated board poses various challenges for manufacture, processing and use. The following series of articles examines specific solution approaches particularly in the context of corrugating rolls in greater detail. These highly specialized machine elements remain to this day the heart of every corrugated board production line, which is why we are putting them in the spotlight.