device and process for the manufacture of hollow plastic objects to screen out defective plastic preforms that are to be molded into their desired shape in a molding station before they reach the molding station , the conveyor track leading into the molding station comprising a screening area through which the preforms are conveyed in such a way that they are loosely supported on only one side , wherein screening apparatuses are provided in the screening area to screen out defective plastic preforms in response to signals from an inspection station .