Apparatus and method for strengthening blow molded articles

A method for strengthening a blow molded article, the article formed from a preform in a blow molding machine that includes a heating station and a blow molding station, the method comprising the steps of:

• transporting the preform in a carrier along a path through the heating station and the blow molding station;
• heating the preform in the heating station;
• providing an air nozzle between the heating station and the blow molding station adjacent to the path of the preform and fixed in position with respect to the path;
• rotating the preform as it is transported past the nozzle;
• directing a jet of air through the nozzle towards the preform, the jet of air being cooler than the preform to form a process ring on a selected portion of the preform;
• and
• molding the preform in the blow molding station.

A method for modifying a blow molding machine to strengthen blow molded articles formed from preforms, the machine including a heating station, a blow molding station, a transport system for transporting the preforms from the heating station to the blow molding station, and a rotation mechanism for rotating the preforms, the method comprising the steps of:

• extending the rotation mechanism into a standby station between the heating station and the blow molding station to provide rotation to the preforms in the standby station;
• positioning a nozzle adjacent to the standby station, the nozzle subjecting the preforms to a jet of air in the standby station;
• and
• molding the preforms into blow molded articles in the blow molding station after the preforms are subjected to the jet of air.