Sack and box stack cover film manufacture involves air cooling a transverse weld on a tubular film from below and cutting the tube adjacent to the weld from below

摘要

A continuous side-folded tubular plastic film (2) for use in a stretched cover packaging machine is transversely welded (25). A cooled air flow at a temperature well below that of the welding temperature is then blown from the underside onto the welded area. The tube section incorporating the weld is then cut from the continuous tube immediately adjacent to the weld line to form a cover (2'). An Independent claim is made for a welding, cooling and cutting head (1) for production of a plastic film cover which includes a welded seam cooling system (26) comprising two hollow air tubes (38), one on each side of the tube (2) below the welding bars with nozzles (27) facing upwards at an angle towards the tube faces (5).