A molding device for molding a plastic material, comprising: a center core comprising a plurality of center core inlets and a plurality of center core outlets; a bubbler coupled with the center core and comprising a bubbler inlet and a bubbler outlet, wherein the bubbler is configured to further define a fluid coolant flow path so that coolant flows in through the bubbler inlet through to the center core inlets, and wherein the bubbler is configured to further define the fluid coolant flow path so that coolant flows from the center core outlets and out through the bubbler outlet; a cooling ring disposed around the center core, the cooling ring comprising a plurality of internal grooves, a plurality of traversing channels, a plurality of arcuate grooves, and a plurality of external grooves; and a thread core disposed around the cooling ring; wherein the center core, the cooling ring, and the thread core are configured to define a fluid coolant flow path through which coolant may flow into the plurality of center core inlets, through a plurality of internal channels bounded by the plurality of internal grooves and the center core, through the plurality of traversing channels, through a plurality of arcuate channels bounded by the plurality of arcuate grooves and the thread core, through a plurality of external channels bounded by the plurality of external grooves and the thread core, and through the plurality of center core outlets; wherein the center core, the cooling ring, and the thread core are configured to define the fluid coolant flow path with cross sectional areas configured to control the coolant flow; wherein the center core is configured to define the plurality of center core inlets with a greater combined cross sectional area than the bubbler inlet; wherein the center core and the cooling ring are configured to define the plurality of internal channels with a smaller combined cross sectional area than the bubbler inlet; and wherein the thread core and the cooling ring are configured to define the plurality of external channels with a smaller combined cross sectional area than the plurality of internal channels. a center core comprising a plurality of center core inlets and a plurality of center core outlets; a bubbler coupled with the center core and comprising a bubbler inlet and a bubbler outlet, wherein the bubbler is configured to further define a fluid coolant flow path so that coolant flows in through the bubbler inlet through to the center core inlets, and wherein the bubbler is configured to further define the fluid coolant flow path so that coolant flows from the center core outlets and out through the bubbler outlet; a cooling ring disposed around the center core, the cooling ring comprising a plurality of internal grooves, a plurality of traversing channels, a plurality of arcuate grooves, and a plurality of external grooves; and a thread core disposed around the cooling ring; wherein the center core, the cooling ring, and the thread core are configured to define a fluid coolant flow path through which coolant may flow into the plurality of center core inlets, through a plurality of internal channels bounded by the plurality of internal grooves and the center core, through the plurality of traversing channels, through a plurality of arcuate channels bounded by the plurality of arcuate grooves and the thread core, through a plurality of external channels bounded by the plurality of external grooves and the thread core, and through the plurality of center core outlets; wherein the center core, the cooling ring, and the thread core are configured to define the fluid coolant flow path with cross sectional areas configured to control the coolant flow; wherein the center core is configured to define the plurality of center core inlets with a greater combined cross sectional area than the bubbler inlet; wherein the center core and the cooling ring are configured to define the plurality of internal channels with a smaller combined cross sectional area than the bubbler inlet; and wherein the thread core and the cooling ring are configured to define the plurality of external channels with a smaller combined cross sectional area than the plurality of internal channels.