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

• US 7,320,589 B2
• Filed: 02/26/2004
• Issued: 01/22/2008
• Est. Priority Date: 02/26/2003
• Status: Expired due to Fees

• Current Assignee: Mold Masters 2007 Limited (Hillenbrand Incorporated)
• Original Assignee: Mold Masters 2007 Limited (Hillenbrand Incorporated)
• Inventors: Colonico, Gino, Babin, Denis
• Primary Examiner(s): Gupta; Yogendra N.
• Assistant Examiner(s): Ewald; Maria Veronica
• Application Number:
  US10/786,017
• Publication Number:
  US 20040164459A1
• Time in Patent Office: 1,426 Days
• Field of Search: 425/572, 425/588, 425/338, 425/234, 264/328.8, 264/328.12
• US Class Current: 425/572
• CPC Class Codes: B29C 2045/308 Mixing or stirring devices
• CPC Class Codes: B29C 45/2725 Manifolds
• CPC Class Codes: B29C 45/2737 Heating or cooling means therefor B29C45/7331 takes precedence
• CPC Class Codes: B29C 45/30 Flow control means disposed within the sprue channel, e.g. "torpedo" construction
• CPC Class Codes: B29C 45/322 Runner systems for distributing the moulding material to the stacked mould cavities

Abstract

A method and apparatus for rotating a cross-sectional asymmetrical condition of a laminar flowing material is provided in a hot runner system for supplying a laminar flowing material. The hot runner system has (i) an upstream melt passage, (ii) a pair of intermediary melt passages downstream from the upstream melt passage, and (iii) for at least one intermediary melt passage, an associated pair of downstream melt passages downstream from the at least one intermediary melt passage. The cross-sectional asymmetrical condition of a laminar flowing material is rotated by providing a bending path for orienting at least one path outlet relative to a path inlet to rotate the cross-sectional asymmetrical condition of the laminar flowing material such that the cross-sectional asymmetrical condition is substantially equally divided between the two downstream portions.

Claims

1. An injection molding apparatus comprising:

a hot runner system for supplying a stream of melt, the hot runner system having

an upstream melt passage,

a pair of downstream melt passages downstream from the upstream melt passage and disposed substantially transverse to the upstream melt passage; and

a separate flow rotator disposed at a first junction between the upstream melt passage and the pair of downstream melt passages, wherein the flow rotator is substantially cylindrical and includes;

an inlet aligned with the upstream melt passage to receive the melt stream from the upstream melt passage,

an inlet passage receiving melt from the inlet and following an arcuate path such that a downstream portion of the inlet passage is substantially perpendicular to the upstream melt passage 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 to a respective first and second outlet, wherein the first and second outlets are disposed on opposite sides of the flow rotator, wherein the first and second outlets each communicate with a respective one of the pair of downstream melt passages such that melt flow from the upstream melt passage is substantially equally divided to flow in opposite directions in the pair of downstream melt passages; and

a plurality of hot runner nozzles in communication with and downstream from the downstream melt passages.

2. The injection molding apparatus as defined in claim 1, wherein the hot runner system is disposed in a manifold.

3. The injection molding apparatus as defined in claim 1, wherein the hot runner system is disposed in a stack mold.

4. The injection molding apparatus as defined in claim 1 wherein the flow path is non-planar.

5. The injection molding apparatus as defined in claim 4 wherein the first junction is disposed in a first plane and the second junction is disposed in second plane parallel to and above the first plane, wherein the first and second outlet passages are curved such that the melt returns to the first plane at the first and second outlets.

6. The injection molding apparatus as defined in claim 1 wherein the flow rotator comprises a one-piece body.

7. The injection molding apparatus as defined in claim 6 wherein the one-piece body comprises an integral heating element.

8. 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.

9. The flow rotator as defined in claim 8 wherein the junction is offset from a plane including the upstream melt passage and the pair of downstream melt passages.

10. The flow rotator as defined in claim 8, wherein the flow rotator comprises one-piece body, wherein the inlet, the inlet passage, the outlet passages and the two outlets are formed in the one-piece body.

11. The flow rotator as defined in claim 10 wherein the one-piece body comprises an integral heating element.

12. 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.

13. The injection molding apparatus as defined in claim 12, wherein the second junction is offset from a plane including the first melt channel and the second melt channel.

14. 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.

15. The injection molding apparatus as defined in claim 14, wherein the flow rotating plug comprises a one-piece body defining the inlet conduit and the two outlet conduits.

16. The injection molding apparatus as defined in claim 14, wherein an axis of the inlet conduit at the intersection is substantially perpendicular to the plane.

17. The injection molding apparatus as defined in claim 14, wherein the two outlet conduits are fully defined by the flow rotating plug.

18. The injection molding apparatus as defined in claim 14, wherein the two outlet conduits are partially defined by the injection manifold.