fluting

Press one stack of the rectangles into each well of the muffin pan, folding or fluting the edges slightly to make an attractive cup.

There’s a top and a bottom, and between them is a bunch of ridged or diagonally reinforced filler called “fluting.”

That fluting is what gives a cardboard box its protective quality; without its flutes, corrugate wouldn’t be corrugate at all — it would just be containerboard.

International Paper customers choose from a fluting guide that extends from A-flute at the thickest to so-called microflutes like E and F.

“Fluting happens at the top,” McDaniel said, indicating a series of whirring cogs on the corrugator that folded the paper into tiny creases — origami at industrial scale.