Molding apparatus

1. A mold stack, comprising:

a core insert, a core find, and a split insert that are configured to cooperate, in use, to define a molding cavity; the core insert defines a ring seat on a medial portion thereof upon which the core ring may be seated, in use, in cooperation with a mounting interface thereon;

the split insert defines a pocket that extends coaxially through a bottom projecting portion thereof within which to receive a projecting portion of the core ring;

the core ring and the split insert being further configured to define a core ring-to-split insert parting line that is within the pocket of the split insert; and

a lock ring to retain the core insert;

a top portion of the molding cavity is split between the core ring and the core insert; an inner surface of the core ring defines a core ring-to-core insert split line in cooperation with an outer medial surface of the core insert;

the core ring defines a split line vent that is configured to cooperate, in use, with the core insert along the core ring-to-core insert split line for venting, in use, air from the molding cavity;

wherein, the core ring defines a branch conduit that is configured to fluidly connect the split line vent with a trunk pressure conduit that is defined between the core insert, the core ring, and the lock ring of the mold stack.

2. The mold stack of claim 1 , wherein:

a top face of the core ring defines the core ring-to-split insert parting line in cooperation with a recessed face of the pocket in the split insert.

3. The mold stack of claim 2 wherein:

the core ring defines an air nozzle therein that has an outlet aperture on the top face of the core ring for providing, in use, air assisted ejection of a molded article from the core insert.

4. The mold stack of claim 2 , wherein:

the core ring defines a parting line vent in cooperation with the split insert across the core ring-to-split insert parting line for venting, in use, air from the molding cavity.

5. The mold stack of claim 4 , wherein:

the top face of the core ring includes a plurality of semi-annular pads that are separated by a plurality of vent slots, wherein the plurality of semi-annular pads are configured to provide a shut-off, in use, in contact with the recessed face of the pocket in the split insert, and further wherein the plurality of vent slots are configured to form the parting line vent, in use, in contact with the recessed face of the pocket in the split insert.

6. The mold stack of claim 1 , wherein:

the core ring defines a retainer interface that is configured to cooperate, in use, with a retaining interface on the core insert to retain the core ring to the core insert.

7. The mold stack of claim 6 , wherein:

the retaining interface on the core insert is a core thread and the retainer interface is a ring thread, wherein the ring thread and the core thread are adapted to cooperate to releasably engage with relative rotation between the core ring and the core insert.

8. The mold stack of claim 1 , wherein:

the core ring defines a retainer interface that is configured to cooperate, in use, with a retaining interface on the lock ring of the mold stack to retain the core ring to the core insert.

9. The mold stack of claim 1 , wherein:

the core ring has been structured to define a first split insert seat for receiving a second projecting portion of the split insert.

10. The mold stack of claim 9 wherein:

the first split insert seat has a form, as shown, of a conical female taper.