Method and device for folding along a generatrice of a metallic blank a multilayer structure.

摘要

The procedure, for use with a sheet containing two layers (2, 3) of metal with a layer (4) of a polymer between them, consists of generating a controlled creep in at least one of the metal layers as the sheet is being bent so as to maintain a constant volume of material in the fold. The controlled creep can be generated in the inner layer (2) of the fold on either side of the fold line so that material is forced towards the inside of the fold, or it can be generated in the outer layer (3) by stretching the material towards the outside of the fold. The creep can also be generated in two stages, one towards the inside and the other towards the outside of the fold, in the inner and outer layers respectively. The procedure is carried out with a one-piece matrix and a die with two jaws.