Patent ID: 7721578

Claim:
A method for forming an outwardly curled portion of a metal can formed from a metal sheet having a resin film at least on an inner face, comprising: flanging and folding a predetermined length of a trimmed opening portion of the metal can outwardly to form a folded portion comprising two layers of the metal sheet; flanging the folded portion sequentially part by part in the circumferential direction, using a disc-shaped spinning die having a rotating shaft inclined with respect to an axial direction of the can, by applying a pressure from above by the spinning die, while rotating the can and the spinning die in the same direction and keeping a portion of an outer circumference of a working face of the spinning die in substantial line contact with the opening of the can along an inside surface of the can to form a flanged portion; and folding the flanged portion downwardly by sequentially folding the flanged portion part by part in the circumferential direction by applying a sideways pressure by an annular internal roller which moves in the direction perpendicular to the axial direction of the can, while keeping the annular internal roller in a substantially linear contact from outside with the opening portion of the rotating can to form a refolded portion comprising three layers of the metal sheet in which adjacent surfaces of the three layers of the metal sheet are closely contacted with one another via the resin film except for upper and lower ends of the refolded portion.