Hot runner manifold plug for rheological balance in hot runner injection molding

In a hot runner system for supplying a laminar flowing material, the hot runner system having an upstream melt passage and a pair of downstream melt passages downstream from and substantially transverse to the upstream melt passage;

• a flow-rotator for rotating a cross-sectional asymmetrical condition of a laminar flowing material in the hot runner system, the flow rotator comprising:
• an inlet for receiving the laminar flowing material;
• an inlet passage for receiving the laminar flowing material from the inlet, the inlet passage bending such that a downstream portion of the inlet passage is substantially perpendicular to the upstream passage where the laminar flowing material enters the inlet;
• and
• first and second outlet passages communicating with the inlet passage such that the laminar flowing material is split into two streams at a junction between the inlet passage and the outlet passages, wherein each outlet passage has a curved path from the junction to a respective first and second outlet, wherein the first and second outlets each communicate with a respective one of the pair of downstream melt passages such that the laminar flowing material from the upstream melt passage is substantially equally divided to flow in opposite directions in the pair of downstream melt passages,
• wherein the flow rotator is a substantially cylindrically shaped plug.

An injection molding apparatus comprising:

• an injection manifold having a first melt channel and a second melt channel, wherein the second melt channel is substantially transverse with respect to the first melt channel;
• a separate plug having a cylindrical body disposed within the manifold at a first junction between the first melt channel and the second melt channel, the separate plug including:
• an inlet aligned with the first melt channel and having an unrestricted flow path to receive a stream of melt flowing through the manifold,
• an inlet passage following an arcuate path such that a downstream portion of the inlet passage is substantially perpendicular to the first melt channel where the melt stream enters the inlet, and
• a first outlet passage and a second outlet passage communicating with the inlet passage such that the flow of melt is split into two streams at a second junction between the inlet passage and the outlet passages, wherein each outlet passage has a curved path from the second junction a respective first and second outlet, wherein the first and second outlets are disposed on opposite sides of the plug, wherein the first and second outlets each communicate with the second melt channel such that melt flow from the first melt channel is substantially equally divided to flow in opposite directions in the second melt channel.

An injection molding apparatus comprising:

• an injection manifold having a primary runner and two secondary runners, a plane defined by the primary runner and the secondary runners;
• and
• a flow rotating plug installed in the injection manifold to connect the primary runner and the secondary runners, the flow rotating plug defining:
• an inlet conduit having an arcuate path extending between an inlet and an intersection offset from the plane, the inlet being connected to the primary runner;
• and
• two outlet conduits, each outlet conduit extending in a curve from the intersection back to the plane and to a respective outlet connected to a respective one of the secondary runners.