Which flute, and why
The board is the same idea every time: two liners with a fluted medium glued between them. What changes is how tall the flutes are and how close together. That single choice decides what the box can do.
Taller flutes cushion, shorter flutes crush less
A tall flute holds more air between the liners, so it absorbs shock. A short flute packs more arches into the same length, so more of them share a load pressing down on the wall. Those two properties pull in opposite directions, which is why there is no single best profile.
We do not publish flute heights in millimetres. The corrugating medium data we work from is a scan we cannot read numerically, and flute height varies by mill and by machine in any case. The relative geometry below is real; the dimensions come with the quotation.
| Flute | Profile | What it is for |
|---|---|---|
| A | Tallest common profile | Most air between the liners, so it cushions best and stacks well. The choice when the box protects something fragile. |
| C | General purpose | Between A and B on both cushioning and crush. Most shipping cases are C unless there is a reason not to be. |
| B | Shorter and denser | Flatter surface takes print better and the closer flutes resist crushing. Used where the box is handled a lot or printed well. |
| E | Thin wall, dense flutes | Behaves almost like folding carton but with corrugated strength — retail packs, small cases, e-commerce boxes on a shelf. |
| BC | Double wall | B on top of C in one board: two flutes, three liners. For heavy contents and high stacks where a single wall would collapse. |
Relative geometry only. Flute heights are mill and machine specific and are confirmed with the quotation.
Double wall is not just 'stronger'
BC is B on top of C in one board — two fluted mediums and three liners, not four. The middle liner is shared. It is for heavy contents and high stacks, where a single wall would collapse before the pallet is built.
It is also thicker, which changes every downstream dimension: the case gets bigger outside for the same inside, and fewer fit in the container. That trade is usually what the decision comes down to.
What to send with the enquiry
The internal dimensions, the contents weight, how high it stacks and how long it sits stacked. If it is printed, say what the print is — a flatter surface takes fine work better, and that pushes towards the shorter profiles.
Board grade, liner weights and medium weight are then specified against that, not chosen from a catalogue in advance.
Questions
What is the difference between B flute and C flute?
C is taller, so it cushions more and gives a thicker wall. B is shorter and denser, so it resists crushing better and takes print on a flatter surface. Most shipping cases are C unless there is a reason not to be.
Which flute is best for printed retail boxes?
E flute, usually. It is thin-walled with very dense flutes, so it behaves close to a folding carton while keeping corrugated strength.
What flute heights do you supply?
Heights are mill and machine specific and are confirmed with the quotation. Send the box dimensions, the contents weight and the stacking requirement.