B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
B31F—MECHANICAL WORKING OR DEFORMATION OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
B31F1/00—Mechanical deformation without removing material, e.g. in combination with laminating
B31F1/20—Corrugating; Corrugating combined with laminating to other layers
B31F1/22—Making webs in which the channel of each corrugation is longitudinal with the web feed