Nozzle having a nozzle body with heated and unheated nozzle body segments

1. An injection molding apparatus comprising:

a manifold having a manifold channel;

a nozzle having a nozzle body including an upstream nozzle body segment having an upstream melt channel, an intermediate nozzle body segment having an intermediate melt channel, and a downstream nozzle body segment having a downstream melt channel, said intermediate nozzle body segment disposed between said upstream nozzle body segment and said downstream nozzle body segment such that said upstream melt channel, intermediate melt channel and downstream melt channel collectively define a nozzle channel in fluid communication with said manifold channel; and

means for connecting said intermediate nozzle body segment with said downstream nozzle body segment such that said intermediate nozzle body segment is not movable relative to said downstream nozzle body segment, wherein said upstream and downstream nozzle body segments are heated and said intermediate nozzle body segment is substantially devoid of a nozzle heater.

2. The injection molding apparatus as claimed in claim 1 , further comprising means for conducting heat from said upstream and downstream nozzle body segments along the length of said intermediate nozzle body segment.

3. The injection molding apparatus as claimed in claim 2 , wherein said means for conducting comprises a thermally conductive layer covering at least a portion of said intermediate nozzle body segment.

4. The injection molding apparatus as claimed in claim 3 , wherein said thermally conductive layer comprises a coating covering at least a portion of said intermediate nozzle body segment.

5. The injection molding apparatus as claimed in claim 3 , wherein said thermally conductive layer is a sleeve.

6. The injection molding apparatus as claimed in claim 2 , further comprising a coating layer covering said means for conducting.

7. An injection molding apparatus as claimed in claim 6 , wherein said coating layer is comprised of ceramic.

8. The injection molding apparatus as claimed in claim 1 , further comprising:

a first thermocouple coupled to said upstream nozzle body segment; and

a second thermocouple coupled to said downstream nozzle body segment.

9. The injection molding apparatus as claimed in claim 8 , further comprising:

a third thermocouple coupled to said intermediate nozzle body segment.

10. An injection molding apparatus comprising:

a manifold having a manifold channel;

a nozzle having a nozzle body including an upstream nozzle body segment having an upstream melt channel, an intermediate nozzle body segment having an intermediate melt channel, and a downstream nozzle body segment having a downstream melt channel, said intermediate nozzle body segment disposed between said upstream nozzle body segment and said downstream nozzle body segment such that said upstream melt channel, intermediate melt channel and downstream melt channel collectively define a nozzle channel in fluid communication with said manifold channel

means for connecting said intermediate nozzle body segment with said downstream nozzle body segment, wherein said upstream and downstream nozzle body segments are heated and said intermediate nozzle body segment is substantially devoid of a nozzle heater; and

a plurality of copper rods disposed longitudinally through said second nozzle body segment for conducting heat from said upstream and downstream nozzle body segments along the length of said intermediate nozzle body segment.

11. An injection molding apparatus as claimed in claim 1 , wherein said intermediate nozzle body segment is removably connected to at least one of said upstream nozzle body segment and said downstream nozzle body segment.

12. An injection molding apparatus as claimed in claim 1 , wherein said intermediate nozzle body segment is made from a thermally conductive material.

13. The injection molding apparatus as claimed in claim 1 , wherein said means for connecting comprises a connection by a threaded engagement, welding, brazing, fusing, a press fit engagement, or an interference fit engagement.

14. A nozzle for use in an injection molding apparatus having a manifold and a mold gate, said nozzle comprising:

a nozzle body including

a first nozzle body segment disposed adjacent said manifold having a first melt channel,

a second nozzle body segment having a second melt channel, and

a third nozzle body segment disposed adjacent said mold gate and having a third melt channel, said second nozzle body segment being disposed between said first nozzle body segment and said third nozzle body segment such that said first, second and third melt channels collectively define a nozzle melt channel; and

means for connecting said second nozzle body segment and said third nozzle body segment such that said second nozzle body segment is not slidable relative to said third nozzle body segment, wherein said first and third nozzle body segments are heated and said second nozzle body segment is substantially devoid of a nozzle heater.

15. The nozzle as claimed in claim 14 , wherein said second nozzle body segment is removably connected to at least one of said first nozzle body segment and said third nozzle body segment.

16. The nozzle as claimed in claim 14 , wherein said second nozzle body segment is made of a thermally conductive material.

17. The nozzle as claimed in claim 14 , wherein said means for connecting comprises a connection by a threaded engagement, welding, brazing, fusing, a press fit engagement, or an interference fit engagement.

18. An injection molding apparatus having a mold gate, said apparatus comprising:

a manifold having a manifold channel; and

a nozzle having a nozzle body including a first nozzle body segment adjacent said manifold and having a first melt channel, a second nozzle body segment having a second melt channel, and a third nozzle body segment adjacent said mold gate and having a third melt channel, said second nozzle body segment disposed between said first nozzle body segment and said third nozzle body segment such that said first, second and third melt channels collectively define a nozzle melt channel,

wherein said first and third nozzle body segments are heated and said second nozzle body segment does not have a heater in contact with it, and wherein said second nozzle body segment is connected to said third nozzle body segment and said first nozzle body segment such that a portion of said second nozzle body segment directly contacts said third nozzle body segment and said first nozzle body segment.

19. An injection molding apparatus comprising:

a manifold having a manifold channel; and

a nozzle having a nozzle body including an upstream nozzle body segment having an upstream melt channel, an intermediate nozzle body segment having an intermediate melt channel, and a downstream nozzle body segment having a downstream melt channel, said intermediate nozzle body segment disposed between said upstream nozzle body segment and said downstream nozzle body segment such that said upstream melt channel, said intermediate melt channel and said downstream melt channel collectively define a nozzle channel,

wherein said first and third nozzle body segments are heated and said intermediate nozzle body segment is heated substantially passively, wherein said intermediate nozzle body segment is connected to said downstream nozzle body segment, and wherein an entire upper half of said downstream nozzle body segment is spaced from a mold plate.

20. An injection molding apparatus comprising:

a manifold having a manifold channel;

a nozzle having a nozzle body including an upstream nozzle body segment having an upstream melt channel, an intermediate nozzle body segment having an intermediate melt channel, and a downstream nozzle body segment having a downstream melt channel, said intermediate nozzle body segment disposed between said upstream nozzle body segment and said downstream nozzle body segment such that said upstream melt channel, intermediate melt channel and downstream melt channel collectively define a nozzle channel in fluid communication with said manifold channel

means for connecting said intermediate nozzle body segment with said downstream nozzle body segment, wherein said upstream and downstream nozzle body segments are heated and said intermediate nozzle body segment is substantially devoid of a nozzle heater;

a heater sleeve disposed around an exterior surface of said nozzle, said heater sleeve in contact with said upstream nozzle body segment and said downstream nozzle body segment and having a cut-out formed therein along substantially the length of said intermediate nozzle body segment; and

a nozzle heater in contact with said heater sleeve.

21. The injection molding apparatus as claimed in claim 1 , further comprising:

a first mold plate disposed about said upstream nozzle body segment; and

a second mold plate disposed about said intermediate nozzle body segment.

22. The injection molding apparatus as claimed in claim 21 , further comprising:

a third mold plate disposed downstream of said downstream nozzle body segment.

23. The injection molding apparatus as claimed in claim 22 , wherein said second mold plate and said third mold plate define a mold cavity.

24. The injection molding apparatus as claimed in claim 21 , wherein said first mold plate and said second mold plate are releasably connected to each other.

25. The injection molding apparatus as claimed in claim 22 , wherein said second mold plate and said third mold plate are releasably connected to each other.

26. An injection molding apparatus having a plurality of mold gates, said apparatus comprising:

a manifold; and

a plurality of nozzles disposed between said manifold and said mold gates, wherein at least one of the plurality of nozzles has a nozzle body including a first nozzle body segment adjacent said manifold, a second nozzle body segment, and a third nozzle body segment adjacent one of said mold gates, said second nozzle body segment disposed between said first nozzle body segment and said third nozzle body segment, and wherein at least two of said nozzles are of different lengths,

wherein said first and third nozzle body segments of said at least one nozzle are heated and said second nozzle body segment does not have a heater in contact with it.

27. The injection molding apparatus as claimed in claim 26 , wherein said second nozzle body segment of said at least one nozzle is variable in length.

28. The injection molding apparatus as claimed in claim 26 , wherein at least two of said nozzles are in fluid communication with separate mold cavities.

29. The injection molding apparatus as claimed in claim 5 , further comprising:

a first retaining sleeve covering at least a portion of said upstream nozzle body segment; and

a second retaining sleeve covering at least a portion of said downstream nozzle body segment.

30. The injection molding apparatus as claimed in claim 29 , wherein said first retaining sleeve and said second retaining sleeve are in abutment with said conductive layer.

31. The injection molding apparatus as claimed in claim 29 , wherein said first retaining sleeve and said second retaining sleeve are each connected to said conductive layer by a shoulder engagement.

32. The nozzle as claimed in claim 14 , further comprising a fourth nozzle body segment having a fourth melt channel and a fifth nozzle body segment having a fifth melt channel, said fourth nozzle body segment disposed between said third nozzle body segment and said fifth nozzle body segment such that said first, second, third, fourth and fifth melt channels collectively define a nozzle melt channel.

33. The injection molding apparatus as claimed in claim 1 , further comprising a conductive washer interposed between said upstream nozzle body segment and said intermediate nozzle body segment.

34. The injection molding apparatus as claimed in claim 1 , further comprising a conductive washer interposed between said intermediate nozzle body segment and said downstream nozzle body segment.

35. The injection molding apparatus as claimed in claim 1 , wherein said intermediate melt channel has a diameter that varies along the length of said intermediate nozzle body segment.

36. An injection molding apparatus comprising:

a manifold having a manifold channel;

a nozzle having a nozzle body including an upstream nozzle body segment having an upstream melt channel, an intermediate nozzle body segment having an intermediate melt channel, and a downstream nozzle body segment having a downstream melt channel, said intermediate nozzle body segment disposed between said upstream nozzle body segment and said downstream nozzle body segment such that said upstream melt channel, intermediate melt channel and downstream melt channel collectively define a nozzle channel in fluid communication with said manifold channel; and

means for connecting said intermediate nozzle body segment with said downstream nozzle body segment, wherein said upstream and downstream nozzle body segments are heated and said intermediate nozzle body segment is substantially devoid of a nozzle heater, and wherein said intermediate nozzle body segment has a mass or volume that is at least ten percent of the overall nozzle body mass or volume.