Abstract: A valve pin actuator is disclosed that includes a cylinder mounted to the clamping plate, a piston slidably mounted in the cylinder, and a valve pin assembly carried by the piston. A hydraulic or pneumatic circuit is provided for controlling the movement of the piston, and in turn translation of the valve pin between the seated and unseated positions. The valve pin assembly includes a first part removably secured to the piston so as to translate therewith, and a second part for receiving the valve pin and secured to said manifold. The actuator assembly enables removal of the clamping plate without removal of the valve pin assembly, and also adjusting of the valve pin without removal of the clamping plate. The assembly further provides a clearance between the piston and valve pin assembly, to accommodate expansion and movement of the manifold that would otherwise cause a side load to be exerted on the valve pin.

Abstract: An injection molding nozzle is provided that includes a heater disposed about an insert seated in the nozzle body. The heater provides extra heat about the insert where heat loss to the mold can cause a reduction in melt temperature. The heater remains on from one injection cycle to the next injection cycle. In one embodiment, a thermocouple is used to measure the temperature about the insert so that the intensity of the heater can be adjusted accordingly. The heater can also be used with nozzles used in multiple nozzle applications to balance the flow of the nozzles.

Abstract: A system and apparatus for injection molding articles of crystallizable polymeric materials in a substantially completely amorphous state is provided. The system includes (i) a mold defining an article formation cavity and an outer cavity connected by a gate, (ii) a melt transport mechanism including a bushing having a distal portion located in the outer cavity in close proximity to the gate inlet, and (iii) a source of molten material. The geometric configurations of the distal portion of the bushing, the inner portion of the outer cavity and the gate, and the relative locations of the distal end of the bushing and the inlet of the gate are each selected such that melt material may flow from the source through the melt transport mechanism and gate into the article formation cavity. The melt transport mechanism is maintained at a temperature above the characteristic crystal melt temperature of the polymeric material.

Abstract: For open bore injection molding, the apparatus includes in combination a hot bushing, a cold mold, and a thin-walled seal. The bushing is adapted to convey molten material from a hot manifold to an article formation cavity in the mold. The mold defines a bore extending into its upper surface, and a gate at the bottom of the bore which communicates with the article formation cavity. The bushing at least partially fits within, and in spaced relation to, the periphery of the bore. The bushing includes an unobstructed lumen therethrough which opens into its lower end and is generally aligned with the gate. The bushing also defines a depressed portion in its outer surface located in closely spaced, circumferential relation to the opening of the lumen into its lower end. The thin-walled seal is formed of metallic material having low thermal conductivity, and has a generally arc-shaped cross-section.

Abstract: An injection molding apparatus and a bushing for use therein. Pressurized molten material flows intermittently from a source through runner channels in a heated manifold and internal lumens in heated bushings for injection through gates into article formation cavities of a mold. Each bushing includes a conically shaped, distalmost section extending substantially centrally into a mold gate. Each bushing also includes a distally opening annular cavity located between its distalmost section and its inner lumen. The annular cavity has outer walls which are substantially parallel to the bushing axis, and inner walls. The inner walls form a distally tapered shoulder having an outer edge and an inner edge. The outer edge extends substantially helically and distally along an axial projection of the proximal portion of the bushing. The inner edge extends substantially helically and distally along an axial projection of the smaller maximum diameter of the conically shaped portion.

Abstract: A system and apparatus for injection molding articles of crystallizable polymeric materials in a substantially completely amorphous state is provided. The system includes (i) a mold defining an article formation cavity and an outer cavity connected by a gate, (ii) a melt transport mechanism including a bushing having a distal portion located in the outer cavity in close proximity to the gate inlet, and (iii) a source of molten material. The geometric configurations of the distal portion of the bushing, the inner portion of the outer cavity and the gate, and the relative locations of the distal end of the bushing and the inlet of the gate are each selected such that melt material may flow from the source through the melt transport mechanism and gate into the article formation cavity. The melt transport mechanism is maintained at a temperature above the characteristic crystal melt temperature of the polymeric material.

Abstract: A hot manifold system for use in the injection molding of plastics is disclosed wherein runner channel heating is accomplished by heat pipes disposed within the manifold adjacent to the runner channels contained therein. The manifold system is an elongated structure having a heat receiving portion and a runner containing portion such that heat input may be applied to the heat receiving portion at an accessible location relative to the mold and conveyed to the remainder of the manifold for uniform heating thereof by the heat pipes.

Abstract: An extruder barrel of a thermoplastic molding machine connected to an injection molding nozzle provided with a plurality of heat pipes distributed around the central bore of the nozzle, each of the heat pipes deriving its thermal input from the extruder barrel itself.