Abstract: Embodiments of the presently-disclosed subject matter include extruder screws. Some embodiments of extruder screws include a screw body for placement in an extruder barrel, a plurality of ridges on the outer surface of the screw body that extend helically from an inlet end to an outlet end of the screw body, each adjacent pair of the ridges defining a channel, and one or more notches each extending across one of the plurality of ridges and between an adjacent pair of the channels. The notches can permit a material to flow from one channel into an adjacent channel, and the notches can define crosscuts that extend along the screw body and helically rotate in an opposite direction relative to the plurality of ridges. Furthermore, some extruder screws can further comprise one or more splitter rings.

Abstract: Embodiments of the presently-disclosed subject matter include extruder screws. Some embodiments of extruder screws include a screw body for placement in an extruder barrel, a plurality of ridges on the outer surface of the screw body that extend helically from an inlet end to an outlet end of the screw body, each adjacent pair of the ridges defining a channel, and one or more notches each extending across one of the plurality of ridges and between an adjacent pair of the channels. The notches can permit a material to flow from one channel into an adjacent channel, and the notches can define crosscuts that extend along the screw body and helically rotate in an opposite direction relative to the plurality of ridges. Furthermore, some extruder screws can further comprise one or more splitter rings.

Abstract: Embodiments of the presently-disclosed subject matter include extruder screws. Some embodiments of extruder screws include a screw body for placement in an extruder barrel, a plurality of ridges on the outer surface of the screw body that extend helically from an inlet end to an outlet end of the screw body, each adjacent pair of the ridges defining a channel, and one or more notches each extending across one of the plurality of ridges and between an adjacent pair of the channels. The notches can permit a material to flow from one channel into an adjacent channel, and the notches can define crosscuts that extend along the screw body and helically rotate in an opposite direction relative to the plurality of ridges. Furthermore, some extruder screws can further comprise one or more splitter rings.

Abstract: Co-extrusion apparatus for manufacturing a laminated plastic film or sheet comprises a plug-type layer sequencer including a plurality of channels for conducting a plurality of polymer flows; a transitional aspect ratio block for inducing the plurality of polymer flows to converge; and a flow velocity profiler cartridge for combining the plurality of polymer flows to form the film. In accordance with one embodiment, the layer sequencer includes a tapered selector pin which minimizes mechanical damage when the selector pin is removed. In accordance with another embodiment, the flow velocity profiler cartridge includes inserts fitting within cavities for controlling the polymer flows which form the layers of the film or sheet manufactured by the apparatus. At least one such insert defines lanes within an associated cavity so as to promote the formation of lanes of differing polymer composition within at least one layer of the laminated sheet or film.

Abstract: Co-extrusion apparatus for manufacturing a laminated plastic film or sheet comprises a plug-type layer sequencer including a plurality of channels for conducting a plurality of polymer flows; a transitional aspect ratio block for inducing the plurality of polymer flows to converge; and a flow velocity profiler cartridge for combining the plurality of polymer flows to form the film. In accordance with one embodiment, the layer sequencer includes a tapered selector pin which minimizes mechanical damage when the selector pin is removed. In accordance with another embodiment, the flow velocity profiler cartridge includes inserts fitting within cavities for controlling the polymer flows which form the layers of the film or sheet manufactured by the apparatus. At least one such insert defines lanes within an associated cavity so as to promote the formation of lanes of differing polymer composition within at least one layer of the laminated sheet or film.

Abstract: An extruder screw for use in the barrel of a plastic materials extruder is formed with a melt section which includes a melt flighting and a compaction channel and which also includes a barrier flight in which only smooth transitions are formed to prevent pressure surges or disruptions. The barrier flight rises radially outwardly of a forward wall of the melt channel, and defines a clearance space with the adjacent wall of the barrel which varies from a maximum at the beginning of the barrier flight to a minimum at the end of the barrier flight. The varying clearance between the barrier flight and the barrel wall approximates the change in viscosity of molten plastic material flowing over the barrier flight from the solids channel into the melt channel, so that a relatively constant shear energy input is applied to the molten plastic material flowing over the barrier flight.

Abstract: A plastic materials screw has a metering section defined by a series of axially extending discontinuous and partially overlapping flightings. The flightings overlap each other by about a half to one turn to define overlapping portions whereby the flow in the primary channel is divided into a pair of secondary flow channels which have velocity profiles normal to the channel root greater than that in the primary channel. At the end of the overlapped portion, the first flighting is discontinued and the second flighting continues with a result that the flows are recombined in a distributive manner to provide improved mixing with a minimum of additional shear stress.