A mixing device for use with a manifold in an injection molding apparatus. The mixing device has a body which has a melt channel therethrough. The melt channel has a plurality of increasing sections which have an increasing cross-sectional area in a downstream direction, and a number of decreasing sections which have a decreasing cross-sectional area in a downstream direction. The increasing and decreasing sections alternate with each other.
1. An injection molding apparatus, comprising:
a manifold, said manifold having a melt source inlet, said manifold having a plurality of runners downstream from said melt source inlet, said manifold having at least one runner having a mixing device, said mixing device having a central melt channel with a plurality of increasing sections, which have an increasing cross-sectional area in the downstream direction, and a plurality of decreasing sections, which have a decreasing cross-sectional area in the downstream direction, said increasing and decreasing sections alternating with each other along a length of said central melt channel; and
a mold cavity block, said mold cavity block having a mold cavity downstream from said runners.
2. The injection molding apparatus as claimed in claim 1 , wherein each of said plurality of runners downstream from said melt source inlet includes a mixing device.
3. The injection molding apparatus as claimed in claim 2 , wherein said mold cavity block has a mold cavity downstream from each of said plurality of runners.
4. The injection molding apparatus as claimed in claim 1 , further comprising:
a plurality of manifolds, each manifold having a melt source inlet and at least one runner downstream from said melt source inlet, wherein each of said runners includes a mixing device; and
a plurality of mold cavity blocks having mold cavities downstream from each of said runners.
5. The injection molding apparatus as claimed in claim 1 , wherein said mixing device is positioned adjacent a downstream end of said runner.
6. The injection molding apparatus as claimed in claim 2 , wherein each of said mixing devices is positioned adjacent a downstream end of said runner.
7. The injection molding apparatus as claimed in claim 1 , further comprising:
a nozzle having a nozzle channel, said nozzle channel being downstream from said at least one runner and upstream from said mold cavity.
8. The injection molding apparatus as claimed in claim 1 , wherein the manifold includes a split in said at least one runner, whereby a melt flow in said runner is divided into a plurality of melt flows, and wherein said mixing device is positioned upstream of said split.
9. An injection molding apparatus comprising:
(a) an injection manifold having a plurality of manifold melt channels adapted to guide a melt flow, wherein at least a portion of at least one manifold melt channel has a generally circular cross-section in a plane perpendicular to the direction of melt flow and wherein said cross-section has a plurality of diameter values that varies alternatively and repeatedly along the direction of melt flow;
(b) a plurality of injection nozzles in fluid communication with the manifold melt channels; and
(c) a plurality of mold cavities in communication with the nozzles.
10. An injection molding apparatus comprising:
(a) an injection manifold having a plurality of manifold melt channels adapted to guide a melt flow, wherein at least a portion of at least one manifold melt channel has a melt mixing portion configured to provide a melt flow rate that varies alternatively and repeatedly along a melt channel longitudinal axis between an inlet and an outlet of said mixing portion;
(b) a plurality of injection nozzles in fluid communication with the manifold melt channels; and
(c) a plurality of mold cavities in communication with the nozzles.
11. An injection molding apparatus comprising:
a manifold having, a manifold body, the manifold body having a plurality of manifold melt channels defined therein for guiding a melt flow, wherein at least a portion of at least one melt channel is a melt mixing portion having a central melt channel and having a plurality of juxtaposed sections in series along a length of the central melt channel, wherein each section has a different cross-sectional area than an adjacent section.
12. An injection molding apparatus comprising:
(a) an injection manifold having a plurality of manifold melt channels adapted to guide a melt flow, wherein at least a portion of at least one manifold melt channel has a melt mixing section having a generally circular cross-section about a melt channel longitudinal axis with a plurality of portions having alternating increasing and decreasing diameters from an inlet to an outlet of the melt mixing section;
(b) a plurality of injection nozzles in fluid communication with the manifold melt channels; and
(c) a plurality of mold cavities in communication with the nozzles.
13. An injection molding apparatus comprising:
(a) an injection manifold having a plurality of manifold melt channels adapted to guide a melt flow, wherein at least a portion of at least one manifold melt channel has a melt channel axis and has a generally circular cross-section about the melt channel axis, wherein the melt channel has a melt mixing section having a central flow channel along the melt channel axis with a diameter that varies along a length of the melt mixing section from an inlet to an outlet thereof;
(b) a plurality of injection nozzles in fluid communication with the manifold melt channels; and
(c) a plurality of mold cavities in communication with the nozzles.
14. An injection molding apparatus comprising:
(a) an injection manifold having a plurality of manifold melt channels adapted to guide a melt flow, wherein at least a portion of at least one manifold melt channel has a melt mixing section that is configured to provide a melt flow velocity that varies along a melt channel central axis from an inlet to an outlet of the melt mixing section;
(b) a plurality of injection nozzles in fluid communication with the manifold melt channels; and
(c) a plurality of mold cavities in communication with the nozzles.
15. The injection molding apparatus according to claim 9 , wherein said cross-section having a plurality of diameter values is part of a melt channel of a separate melt mixing device.
16. The injection molding apparatus according to claim 15 , wherein said melt mixing device has a body made of two blocks each including a portion of the mixing device melt channel.
17. The injection molding apparatus according to claim 10 , wherein said melt mixing portion is part of a melt channel of a separate melt mixing device.
18. The injection molding apparatus according to claim 16 , wherein said melt mixing device has a body made of two blocks each including a portion of the mixing device melt channel.
19. The injection molding apparatus according to claim 11 , wherein said juxtaposed sections in series are part of a separate melt mixing device.