Post-mold cooling apparatus
View Patent ↗The present invention relates to an improved method and apparatus for injection molding and cooling molded articles such as preforms so as to avoid crystallinity. The apparatus and method make use of a take-off plate for removing articles from a mold, which plate may include heat transfer devices for cooling exterior surfaces of the molded articles or preforms, and a system for cooling in a controlled manner interior surfaces of the molded articles or preforms.
1. Apparatus for cooling a molded article made in an injection mold formed from mold halves, the molded article having a first region at a relatively high heat and an adjacent region at a relatively lower heat, the apparatus comprising:
an end-of-arm tool having at least one holder, the end-of-arm tool being configured to be movable between (i) a first position between the mold halves where it receives the molded article into a respective one of the at least one holder, and (ii) a second position outside of the mold, the at least one holder being configured to hold a molded article at a time when the molded article retains an amount of heat; and
a cooling pin on a frame located adjacent the second position, the cooling pin having a tip, said frame being configured to move relative to the end-of-arm tool to cause insertion of the tip of the cooling pin into the molded article after the end-of-arm tool reaches the second position;
said cooling pin having an internal channel terminating at the tip, said frame and said cooling pin being configured to cause the cooling pin, upon insertion into the molded article by relative movement of the frame and the end-of-arm tool, to be within the molded article but spaced away from the first region and not in contact therewith, said cooling pin being configured to be connectable to a cooling fluid delivery system arranged to force gaseous cooling fluid along the internal channel to cause expulsion of the gaseous cooling fluid from the tip mostly in a direction of the first region to accentuate cooling within at least the first region;
said frame being configured to be positioned, during the expulsion of the gaseous cooling fluid from the tip, with respect to the end-of-arm tool such as to define an open system having a passageway allowing venting of gaseous cooling fluid from an interior of the molded article to an ambient environment; and
said apparatus being configured to be operational, during the expulsion of gaseous cooling fluid from the tip, to distance the frame from the end-of-arm tool, and the passageway of the open system is produced by formation of a space between a region of an external surface of the cooling pin and an open end of the molded article both located within the respective holder.
2. Apparatus according to claim 1 , wherein the apparatus is configured to introduce the tip of the cooling pin into the preform to a depth that allows the coolant to reach and cool an internal dome portion of a preform.
3. Apparatus according to claim 1 , wherein the frame positions the cooling pin within the molded article such that:
i) the tip is displaced a first distance (d) from the first region of the molded article;
ii) a sidewall of said cooling pin is located a second distance (D) from internal sidewalls of the molded article; and
a ratio of the first distance to the second distance (d:D) is in the range of about 1:1 to about 10:1.
4. Apparatus according to claim 1 , wherein the gaseous cooling fluid comprises cooled pressurized air that is blown along the internal channel.
5. Apparatus according to claim 4 , further including a valve for supplying regulated amounts of gaseous cooling fluid to the cooling pin.
6. Apparatus according to claim 1 , wherein the tip has one of a divergent nozzle construction and a straight-walled nozzle construction, and wherein the internal channel and tip, when located within the molded article, focus the gaseous cooling fluid towards a region principally surrounding a first region.
7. Apparatus according to claim 1 , wherein the cooling pin has one of:
i) a varying diameter along its length;
ii) lateral fluid outlets or radial conduits in the sides of the cooling pin, the lateral outlets or radial conduits coupled to the internal channel and arranged to direct cooling fluid to at least one of a neck portion and a body portion of the molded article;
iii) grooves along an exterior surface of the cooling pin;
iv) ribs spaced about the periphery of the cooling pin, the ribs protruding from the cooling pin to reduce, in use, over a length of each rib a dimensional separation of an exterior surface of the cooling pin to the internal wall of the molded article; and
v) a plurality of contact elements along an exterior surface of the cooling pin.
8. Apparatus according to claim 1 , wherein:
the end-of-arm tool supports a plurality of holders; and
the frame includes fewer cooling pins than there are holders on the end-of-arm tool;
whereby, in use, only selected ones of the molded articles in respective holders are cooled by aligned insertion of a tip of a cooling pin into each selected one of the molded articles.
9. Apparatus according to claim 1 , further comprising:
a suction device selectably connectable to the cooling pin, the suction device being operational, in use, after cooling of the molded article by expulsion of the gaseous cooling fluid from the tip, to extract the molded article from its respective holder by drawing the molded article towards the tip under reduced pressure.