Corrugated Cardboard and Boxes

Corrugated board is paper made stiff by shape. On a machine called a corrugator, a fluting paper is softened with steam and pressed between geared rolls into waves, then glued with a starch adhesive to a flat linerboard. A second liner glued to the other side makes single-wall board, which is dried over hot plates and cut into sheets. Flute sizes are lettered: C flute, about 4 mm thick, is the commonest in boxes; B is 3.2 mm, E 1.6 mm. For a box, the board is scored so it bends where wanted and slotted to make flaps, then glued at one edge, the manufacturer's joint, and shipped flat.