What are corrugated flutes and how are they used in corrugated packaging?
Flutes are the “arches” or “squiggly” paper that goes in between the two flat sheets of linerboard in a piece of corrugated board.
C-Flute is the most common flute that you’ll see used in corrugated boxes. There are approximately 39 flutes per foot on a piece of C-Flute board. C-Flute is commonly used for standard shipping boxes, master shippers and corrugated displays.
The second most common flute is B-Flute. B-Flute is a little bit smaller than C-Flute and has about 48 flutes per foot. Because of the smaller flute profile, it’s better for die-cut inserts and die-cut mailers among other things. In general, B-Flute folds up a little nicer than C-Flute does.
E-Flute & F-Flute are considered “Micro-Flutes” because the fluting is so small. They are often used as a more rigid substitute for chipboard boxes or folding cartons which are the material that cereal boxes are made of. Other common uses are for retail packaging and point of purchase displays. You can print a lot higher quality graphics on E-flute than you can on any of the larger flutes.
If you take 3 sheets of flat linerboard and combine them with 2 layers of fluting you have constructed a sheet of double wall corrugated board. The most common grade of double wall would be “BC” which simply means that one of the layers of fluting is constructed of B-Flute and the other from C-flute. You would use a double wall box for shipping very heavy products or anything that needs extra protection.
Architects have known for centuries that an arch is the strongest way to span and support a structure and the same principle is still used today with fluting in a corrugated box.