| Flutes and flute sizes | [German version] |
The commonest flute shape is a sine wave. Flute size is determined on the one hand by flute pitch and on the other by flute height. The flute pitch is the horizontal distance between adjacent flute troughs. The flute height is the vertical trough to peak distance of a flute.
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| Figure 1: Diagram of flute pitch and height |
DIN 55468 recognizes the following flute types:
| Flute shape | Flute pitch | Flute height |
|---|---|---|
| Coarse flute (A flute) | 8.0 – 9.5 mm | 4.0 – 4.9 mm |
| Medium flute (C flute) | 6.8 – 8.0 mm | 3.2 – 4.0 mm |
| Fine flute (B flute) | 5.5 – 6.5 mm | 2.2 – 3.0 mm |
| Microflute (E flute) | 3.0 – 3.5 mm | 1.0 – 1.8 mm |
Due to its size, coarse flute has the best cushioning characteristics (largest spring travel) and the greatest edgewise crush resistance. However, like medium flute, it is not ideally suited to direct printing of the outer facing.