Flat bottom, stand up bag and method of manufacturing the same

摘要

A stand up bag having a flat bottom is formed from a weldable material. The bag includes a seam that closes the bag's bottom wall. The seam is welded flat so that the bag is free of protruding elements. A method for manufacturing the bag includes the step of overlapping the leading edge of a tube and welding the overlapped edge to form the flat, welded seam that allows the bag stand on end in an open condition. The apparatus for manufacturing the bag includes a former that may be moved between retracted and expanded positions with an actuator. The former holds the lower portion of the bag in an expanded position while clamp plates form the overlap seam. A bottom welder is used to weld the overlap seam while the clamp plates hold the bottom of the bag against a portion of the former.