Just-in-time compounding in an injection molding machine

摘要

A plastication unit for an injection molding machine, combining a heated plastication barrel with an entrance port and an exit port on opposing ends of the barrel; a hopper positioned to deliver ingredients to be compounded for injection molding to the entrance port of the barrel; and a helical plastication screw rotatably carried within the barrel and running the length of the barrel between the entrance and exit ports, which is operable to rotate and transmit the ingredients along the length of the barrel; wherein the plastication screw has at least one axial fluted extensional mixing element segment and the ingredients include at least one polymer for injection molding. Methods for injection molding with the plastication unit of the present invention and articles formed by the inventive methods are also disclosed.

主权项

1. An injection molding machine, comprising:
a mold cavity; a heated plastication barrel comprising an entrance port and an exit port on opposing ends of said barrel, said exit port positioned to deliver ingredients compounded for injection molding to said mold cavity; a hopper positioned to deliver ingredients to be compounded for injection molding to the entrance port of said barrel; and a helical plastication screw rotatably carried within said barrel and running the length of said barrel between said entrance and exit ports, which is operable to rotate and transmit said ingredients along the length of said barrel; wherein said plastication screw comprises at least one axial fluted extensional mixing element segment comprising:
(i) at least one inlet channel having an upstream inlet and at least one outlet channel having a downstream outlet in fluid communication with each other, both the inlet channel and the outlet channel being bound on one side by a substantially axially disposed blocking wall which substantially prevents material from flowing therepast,(ii) a plurality of intermediate channels disposed between and in fluid communication with said inlet and outlet channels, said intermediate channels lacking upstream inlets and downstream outlets, and(iii) cross-axial pump members configured to advance ingredients between adjacent channels at an angle to the extruder axis and disposed between each channel.