초록 ▼

A nozzle system is provided for an injection molding machine. The nozzle system includes a nozzle tip that is removably connected to a nozzle body with a sealing and mounting sleeve element. The nozzle body includes a first connector for releasably connecting with a second connector defined on the s

A nozzle system is provided for an injection molding machine. The nozzle system includes a nozzle tip that is removably connected to a nozzle body with a sealing and mounting sleeve element. The nozzle body includes a first connector for releasably connecting with a second connector defined on the sleeve. The sleeve element further includes an alignment bearing for engaging a bearing surface defined on the nozzle body for precisely locating the nozzle tip within the nozzle body along on a predetermined axis. Further embodiments of the invention provide a valve pin disposed in the nozzle body and nozzle tip. The valve pin includes a bearing surface for engaging a guiding surface defined on the second melt channel for aligning the end of the valve pin with a mold gate. Further embodiments also provide an integrally connected nozzle tip and sleeve element.

대표청구항 ▼

1. A nozzle system for an injection molding machine, said system comprising:a nozzle body defining a first portion of a melt channel, said nozzle body defining a bore and a first connector;a nozzle tip defining a second portion of said melt channel, said nozzle tip being sized to fit within said bor

1. A nozzle system for an injection molding machine, said system comprising:a nozzle body defining a first portion of a melt channel, said nozzle body defining a bore and a first connector;a nozzle tip defining a second portion of said melt channel, said nozzle tip being sized to fit within said bore of said nozzle body; anda sealing and mounting element for mounting said nozzle tip to said nozzle body with said first portion and said second portion of said melt channel being fluidly connected, said element defining a second connector for removably connecting with said first connector defined on said nozzle body and an alignment bearing for engaging a bearing surface defined on said nozzle body for precisely aligning said nozzle tip within said nozzle body along a predetermined axis. 2. A nozzle system as claimed in claim 1, further comprising:a valve pin disposed in said second portion of said channel, said valve pin defining a bearing surface for engaging a guiding surface defined on said second portion of said melt channel for guiding said pin into alignment with a gate when said valve pin moves from an open position to a closed position. 3. A nozzle system as claimed in claim 2 wherein at least one flow surface is defined in said valve pin to facilitate a backflow of melt when said valve pin moves to said closed position, said flow surface being defined in portions of a head and a stem of said valve pin. 4. A nozzle system as claimed in claim 3 wherein a plurality of said flow surfaces are defined in said valve pin. 5. A nozzle system as claimed in claim 4 wherein a plurality of said bearing surfaces are defined on said valve pin, each said bearing surface being disposed between a pair of said flow surfaces. 6. A nozzle system as claimed in claim 3 wherein said flow surface has a planar portion and a tapered portion. 7. A nozzle system as claimed in claim 2 wherein a first tolerance gap is defined between a head of said valve pin and the walls of said gate and a second tolerance gap is defined between said bearing surface and said guiding surface, said second tolerance gap being narrower than said first tolerance gap. 8. A nozzle system as claimed in claim 2 wherein a sufficient gap is defined between said bearing surface and said guiding surface to receive a layer of melt for lubricating the relative movement between said valve pin and said nozzle tip. 9. A nozzle system as claimed in claim 1 wherein said nozzle tip material has a high thermal conductivity. 10. A nozzle system as claimed in claim 1 wherein said nozzle tip and said element are integrally connected. 11. An injection nozzle system as claimed in claim 10, wherein said nozzle tip and said element are integrally connected by brazing. 12. An injection molding machine comprising:a stationary platen and at least one movable platen;a manifold disposed in said stationary platen, said manifold defining a manifold melt channel for conducting melt from a melt source;an injection system having an injection nozzle, a mold cavity and a gating device, said injection nozzle defining a nozzle melt channel fluidly connected to said manifold melt channel, said mold cavity being in fluid communication with said nozzle melt channel and said gating device being operatively connected to said injection nozzle for controllably gating the flow of melt from said nozzle melt channel to said mold cavity;said injection nozzle including:a nozzle body defining a first portion of a melt channel, said nozzle body defining a bore and a first connector;a nozzle tip defining a second portion of said melt channel, said nozzle tip being sized to fit within said bore of said nozzle body; anda sealing and mounting element for mounting said nozzle tip to said nozzle body with said first portion and said second portion of said melt channel being fluidly connected, said element defining a second connector for removably connecting with said first connector defined on said nozzle body and an alignment bearing for engaging a bearing surface defined on said nozzle body for precisely aligning said nozzle tip within said nozzle body along a predetermined axis. 13. A machine as claimed in claim 12, further comprising:a valve pin disposed in said second portion of said melt channel, said valve pin defining a bearing surface for engaging a guiding surface defined on said second portion of said melt channel for guiding said pin into alignment with a gate when said valve pin moves from an open position to a closed position. 14. A machine as claimed in claim 13 wherein at least one flow surface is defined in said valve pin to facilitate a backflow of melt when said valve pin moves to said closed position, said flow surface being defined in portions of a head and a stem of said valve pin. 15. A machine as claimed in claim 14 wherein a plurality of said flow surfaces are defined in said valve pin. 16. A machine as claimed in claim 15 wherein a plurality of said bearing surfaces are defined on said valve pin, each said bearing surface being disposed between a pair of said flow surfaces. 17. A machine as claimed in claim 15 wherein said flow surface has a planar portion and a tapered portion. 18. A machine as claimed in claim 14 wherein a first tolerance gap is defined between a head of said valve pin and the walls of said gate and a second tolerance gap is defined between said bearing surface and said guiding surface, said second tolerance gap being narrower than said first tolerance gap. 19. A machine as claimed in claim 13 wherein a sufficient gap is defined between said bearing surface and said guiding surface to receive a layer of melt for lubricating the relative movement between said valve pin and said nozzle tip. 20. A machine as claimed in claim 13 wherein said nozzle tip material has a high thermal conductivity. 21. A machine as claimed in claim 13 wherein said nozzle tip and said element are integrally connected. 22. A machine as claimed in claim 21, wherein said nozzle tip and said element are integrally connected by brazing. 23. An injection molding apparatus comprising:a manifold having a melt channel for receiving melt from a melt source;an injection nozzle for receiving said melt from said melt channel of said manifold, said injection nozzle having a nozzle body with a melt channel, said melt channel being in communication with said melt channel of said manifold;a bore provided in a downstream end of said nozzle body;a nozzle tip sized to fit within said bore of said nozzle body, said nozzle tip having a melt channel for receiving melt from said melt channel of said nozzle body;a mold cavity for receiving said melt from said melt channel of said nozzle tip, flow of melt into said mold cavity being controllable by a gating device;a sealing and mounting element for coupling said nozzle tip to said nozzle body, said sealing and mounting element having a second connector for removably mating with a first connector of said nozzle body;an alignment bearing provided on said sealing and mounting element; said alignment bearing for engaging a bearing surface of said nozzle body to align said nozzle tip within said nozzle body along a predetermined axis. 24. An injection molding apparatus as claimed in claim 23, wherein said sealing and mounting element includes a sleeve that is received in said bore of said nozzle body and a sealing flange, said alignment bearing being provided on said sleeve adjacent said second connector. 25. An injection molding apparatus as claimed in claim 24, wherein said first connector is a threaded inner surface at a downstream end of said bore. 26. An injection molding apparatus as claimed in claim 25, wherein said second connector is a threaded outer surface of said sleeve. 27. An injection molding apparatus comprising:a manifold having a melt channel for receiving melt from a melt source;an injection nozzle for receiving said melt from said melt channel of said manifold, said injection nozzle having a nozzle body with a melt channel, said melt channel being in communication with said melt channel of said manifold;a bore provided in a downstream end of said nozzle body;a nozzle tip sized to fit within said bore of said nozzle body, said nozzle tip having a melt channel for receiving melt from said melt channel of said nozzle body;a mold cavity for receiving said melt from said melt channel of said nozzle tip;a valve pin extending through said melt channel of said nozzle body, said valve pin being axially movable to selectively open a gate to control melt flow into said mold cavity;a nozzle seal coupled to said nozzle body to secure said nozzle tip to said nozzle body;an alignment bearing provided on said nozzle seal; said alignment bearing for engaging a bearing surface of said nozzle body to align said nozzle tip within said nozzle body along a predetermined axis;wherein said valve pin is guided toward said gate by a guiding surface of said nozzle tip. 28. An injection molding apparatus as claimed in claim 27, wherein said valve pin includes at least one flow channel, said flow channel for permitting backflow of melt when said valve pin is moved toward a closed position to engage said gate. 29. A nozzle system for an injection molding machine, said system comprising:a nozzle body defining a first portion of a melt channel, said nozzle body defining a bore and a first connector;a nozzle tip defining a second portion of said melt channel, said nozzle tip being sized to fit within said bore of said nozzle body;a sealing and mounting element for mounting said nozzle tip to said nozzle body with said first portion and said second portion of said melt channel being fluidly connected, said element defining a second connector for removably connecting with said first connector defined on said nozzle body and an alignment bearing for engaging a bearing surface defined on said nozzle body for precisely aligning said nozzle tip within said nozzle body along a predetermined axis; anda valve pin disposed in said second portion of said channel, said valve pin defining a bearing surface for engaging a guiding surface defined on said second portion of said melt channel for guiding said pin into alignment with a gate when said valve pin moves from an open position to a closed position,wherein a sufficient gap is defined between said bearing surface and said guiding surface to receive a layer of melt for lubricating the relative movement between said valve pin and said nozzle tip. 30. An injection molding machine comprising:a stationary platen and at least one movable platen;a manifold disposed in said stationary platen, said manifold defining a manifold melt channel for conducting melt from a melt source;an injection system having an injection nozzle, a mold cavity and a gating device, said injection nozzle defining a nozzle melt channel fluidly connected to said manifold melt channel, said mold cavity being in fluid communication with said nozzle melt channel and said gating device being operatively connected to said injection nozzle for controllably gating the flow of melt from said nozzle melt channel to said mold cavity;said injection nozzle including:a nozzle body defining a first portion of a melt channel, said nozzle body defining a bore and a first connector;a nozzle tip defining a second portion of said melt channel, said nozzle tip being sized to fit within said bore of said nozzle body;a sealing and mounting element for mounting said nozzle tip to said nozzle body with said first portion and said second portion of said melt channel being fluidly connected, said element defining a second connector for removably connecting with said first connector defined on said nozzle body and an alignment bearing for engaging a bearing surface defined on said nozzle body for precisely aligning said nozzle tip within said nozzle body along a predetermined axis; anda valve pin disposed in said second portion of said melt channel, said valve pin de fining a bearing surface for engaging a guiding surface defined on said second portion of said melt channel for guiding said pin into alignment with a gate when said valve pin moves from an open position to a closed position,wherein a sufficient gap is defined between said bearing surface and said guiding surface to receive a layer of melt for lubricating the relative movement between said valve pin and said nozzle tip. 31. An injection molding apparatus comprising:a manifold having a melt channel for receiving melt from a melt source;an injection nozzle for receiving said melt from said melt channel of said manifold, said injection nozzle having a nozzle body having a central melt bore, said central melt bore being in communication with said melt channel of said manifold;a bore provided in a downstream end of said nozzle body;a tip member sized to fit within said bore of said nozzle body, said tip member having a melt duct for receiving melt from said central melt bore of said nozzle body;a mold cavity for receiving said melt from said melt duct of said nozzle tip, flow of melt into said mold cavity being controllable by a gating device;a sleeve member for coupling said tip member to said nozzle body, said sleeve having a second connector for removably mating with a first connector of said nozzle body, wherein said tip member and said sleeve member are integrally connected to one another by brazing; anda tip insert coupled to a downstream end of said tip member. 32. An injection molding apparatus as claimed in claim 31, wherein said tip insert is comprised of a corrosion resistant material. 33. An injection molding apparatus as claimed in claim 32, wherein said tip insert is comprised of tungsten carbide. 34. An injection molding apparatus comprising:a manifold having a melt channel for receiving melt from a melt source;an injection nozzle for receiving said melt from said melt channel of said manifold, said injection nozzle having a nozzle body having a central melt bore, said central melt bore being in communication with said melt channel of said manifold;a bore provided in a downstream end of said nozzle body;a tip member sized to fit within said bore of said nozzle body, said tip member having a melt duct for receiving melt from said central melt bore of said nozzle body;a mold cavity for receiving said melt from said melt duct of said nozzle tip, flow of melt into said mold cavity being controllable by a gating device;a sleeve member for coupling said tip member to said nozzle body, said sleeve having a second connector for removably mating with a first connector of said nozzle body,wherein said tip member and said sleeve member are integrally connected to one another,and wherein said tip member and said sleeve member are comprised of different materials,and wherein said sleeve member is less thermally conductive than said tip member,and wherein said sleeve member is comprised of a seal member and a connector member, said seal member being made of a less thermally conductive material that said connector member. 35. An injection molding apparatus as claimed in claim 34, wherein said tip member and said sleeve member are comprised of different materials. 36. An injection molding apparatus as claimed in claim 35, wherein said sleeve member is less thermally conductive than said tip member. 37. An injection molding apparatus as claimed in claim 36, wherein said tip member includes a shoulder for receiving a rear end of said sleeve member. 38. An injection molding apparatus as claimed in claim 36, wherein said sleeve member includes a shoulder for receiving said tip member, said shoulder being located adjacent a forward portion of said second connector of said sleeve member. 39. An injection molding apparatus as claimed in claim 36, wherein said sleeve member is comprised of a seal member and a connector member, said seal member being made of a less thermally conductive material that said connector member.