Fluting
Fluting refers to the wave pattern formed in corrugating medium between two layers of linerboard. The flute profile — A, B, C, E, and F being the common standards — determines compression strength, cushioning, and printability.
Flute profiles are defined by flute height and flutes-per-foot. A-flute is the tallest (about 5 mm) and provides the most cushioning. C-flute (about 4 mm) is the dominant box-making profile in North America. B-flute (about 3 mm) is shorter and stiffer, common for retail-ready packaging. E-flute (about 1.5 mm) and F-flute (under 1 mm) are micro-flutes used for printed retail boxes where flat panels and fine print matter.
Combinations matter as much as the single-flute spec. Single-wall is one medium between two liners. Double-wall is two mediums and three liners; triple-wall stacks three mediums and four liners. Heavy loads (white goods, industrial parts) ship in double or triple-wall boxes.
Higher flutes give more cushioning but less printability — the linerboard sags slightly between flutes in printing, blurring fine detail. Micro-flutes solve this for retail-ready packaging at the cost of compression strength.
Related terms
- Corrugating mediumCorrugating medium is the fluted middle layer of a corrugated board, sandwiched between two layers of linerboard. The flutes provide compressive cushioning and stack strength; the medium itself does not need the surface qualities of a liner.
- LinerboardLinerboard is the flat, smooth paper layer bonded to either side of a corrugated medium to form a corrugated board. It provides the strength, printability, and outer surface of a cardboard box.
- ContainerboardContainerboard is the umbrella term for paper products used to make corrugated boxes: specifically linerboard and corrugating medium. North American containerboard production is one of the largest paper categories by tonnage.
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