Abstract: A method and device for manufacturing a continuous bag-like package blank, wherein a plane plastic sheet is unwound from a storage reel, and conveyed through edge thickening equipment and a folding device, to a welding device and to a slotting tool to obtain a continuous bag-like package blank, The edge thickening equipment includes a process bed over which the sheet is conveyed, and an extruder device having a (a) first extruder nozzle on the opposite side of the sheet to the process bed aligned continuously to extrude a material bead that is permanently attached to a first edge area the sheet, and (b) a second extruder nozzle placed on the opposite side of the sheet in relation to the process bed aligned continuously to extrude a material bead that is permanently attached to a second edge area of the sheet opposite the first edge area.