Flute Sizes

There Four standard flute sizes are in common use, designated A, B, C and E. The sizes were given their letter names in the sequence of their introduction. A is the largest. B, which is smaller was the next size introduced. C came next, but it is between A and B in size. E is both the most recent and the smallest.

Flute measurements are given with a plus-or-minus allowance. Although the meshed steel rollers that form them are hard, the abrasive nature of the corrugating material and the high speeds of the machines causes wear. Minor variations in size have little effect on performance.

The selection of flute size is determined by the basis weight of the liner board and corrugating material and the performance characteristics desired in the finished container. For double-wall and triple-wall board, the flute sizes for each sheet of corrugated material are usually different. This technique combines their advantages, and prevents any weakness that might result if the flutes were perfectly aligned.