Abstract: A method for manufacturing double ply packaging bags includes feeding a first packaging web, the first packaging web including a window patch that is cut out or pre-cut, feeding a second packaging web, the second packaging web including another window patch that is cut out or pre-cut, applying a fastener assembly to a fed-through packaging web, perpendicular to a window patch, attaching the fastener assembly to the packaging web, attaching the two packaging webs to each other to form a double ply web, and forming a double ply packaging bag with the double ply web. The double ply packaging bag has a front wall and a back wall, where the front wall and the back wall are each formed by the double ply web.

Abstract: The invention concerns a method for making packaging bags (1) with a double wall (31; 31), characterized in that it comprises steps which consist in: unwinding a first packaging sheet (31) wherein a window is cut out or precut; unwinding a second packaging sheet (32) wherein another window is cut out or precut; applying a closure assembly (5) on the moving packaging sheet, perpendicular to a window; fixing the closure assembly on the packaging sheet; fixing the two packaging sheets one on the other to form a double wall, said sheet being then formed into a packaging bags (1).