Method and apparatus for manufacturing bags whose walls contain stretched polyolefin

are described and claimed a method and apparatus for manufacturing bags (2, 2 '), the walls of which contain stretched Polyolephinmaterial, - wherein at least one temperature-induced joining process is effected by at least a portion of the material to be joined (2, 2 ', 3, 3') is heated with a hot air stream (18), - of (18) is generated by air is guided past one or more heating devices (16, 21) initially and is then directed to the material to be joined (2, 2 ', 3, 3'). As a new and inventive is considered that the flow of air (18) pulsating on at least one heater (16, 21) is passed.