Molding system using film heaters and/or sensors

• US 6,305,923 B1
• Filed: 06/12/1998
• Issued: 10/23/2001
• Est. Priority Date: 06/12/1998
• Status: Expired due to Term

• Current Assignee: Husky Injection Molding Systems Limited
• Original Assignee: Husky Injection Molding Systems Limited
• Inventors: Godwin, Harold, Olaru, George, Whiffen, David
• Primary Examiner(s): HEITBRINK, TIMOTHY W
• Application Number:
  US09/096,388
• Time in Patent Office: 1,229 Days
• Field of Search: 425/547, 425/549, 425/570, 425/572, 425/573, 425/143, 425/145
• US Class Current: 425/143
• CPC Class Codes: B29C 2045/2722 Nozzles or runner channels provided with a pressure sensor
• CPC Class Codes: B29C 2045/274 Thermocouples or heat sensors
• CPC Class Codes: B29C 2045/2741 Plurality of independent thermocouples or heat sensors
• CPC Class Codes: B29C 2045/2745 Film-like electrical heaters
• CPC Class Codes: B29C 2045/2746 Multilayered electrical heaters
• CPC Class Codes: B29C 45/02 Transfer moulding, i.e. transferring the required volume of moulding material by a plunger from a "shot" cavity into a mould cavity
• CPC Class Codes: B29C 45/1603 Multi-way nozzles specially adapted therefor
• CPC Class Codes: B29C 45/2701 Details not specific to hot or cold runner channels B29C45/2725 takes precedence
• CPC Class Codes: B29C 45/2711 Gate inserts
• CPC Class Codes: B29C 45/2737 Heating or cooling means therefor B29C45/7331 takes precedence
• CPC Class Codes: B29K 2067/00 Use of polyesters or derivatives thereof, as moulding material

Abstract

Improved mold manifold and hot runner nozzle using thin film elements include at least one active or passive thin film element disposed along a melt channel between the manifold inlet and the hot runner nozzle. Preferably, the thin film element may comprise a thin film heater in direct contact with the molten resin and position to aid in the heat and flow management of the resin within the melt channel. Thin film temperature sensors, pressure sensors, and leak detectors may also be provided in the vicinity of the melt channel to enhance process control in the injection molding machine.

Claims

1. An apparatus to be used in conjunction with an injection molding machine, the apparatus comprising:

a cavity plate;

a core plate disposed relative to the cavity plate so that the core plate and cavity plate together form a cavity space;

a manifold having formed therein an inlet passage for receiving a flow of molten resin from a nozzle of the injection molding machine;

a hot runner nozzle for directing the flow of molten resin from the manifold inlet passage to the cavity space;

a mold gate for regulating the flow of molten resin from the hot runner nozzle to the cavity space, the mold gate together with the hot runner nozzle and the manifold inlet passage defining a melt channel for directing the flow of molten resin from the nozzle of the injection molding machine to the cavity space; and

an active or passive thin film element directly deposited on a flexible substrate which is disposed along an inside of the melt channel upstream of the cavity space so as to contact the molten resin inside the channel.

2. The apparatus of claim 1, further comprising a passive thin film element disposed adjacent to the active thin film element.

3. The apparatus of claim 2, wherein the passive thin film element comprises an electrical insulator.

4. The apparatus of claim 2, wherein the passive thin film element comprises a thermal insulator.

5. The apparatus of claim 2, wherein the passive thin film element comprises a wear resistant material.

6. The apparatus of claim 1, wherein the active thin film element is isolated from the ambient atmosphere.

7. Apparatus according to claim 1, wherein an electrical film temperature sensor is located adjacent said manifold.

8. Apparatus according to claim 1, further comprising an electrical film temperature sensor located adjacent said nozzle.

9. Apparatus according to claim 1, further comprising an electrical film temperature sensor disposed adjacent the mold gate.

10. An apparatus to be used in conjunction with an injection molding machine, the apparatus comprising:

a cavity plate;

a core plate disposed relative to the cavity plate so that the core plate and cavity plate together form a cavity space;

a manifold having formed therein an inlet passage for receiving a flow of molten resin from a nozzle of the injection molding machine;

a hot runner nozzle for directing the flow of molten resin from the manifold inlet passage to the cavity space;

a mold gate for regulating the flow of molten resin from the hot runner nozzle to the cavity space, the mold gate together with the hot runner nozzle and the manifold inlet passage defining a non-flat melt channel for directing the flow of molten resin from the nozzle of the injection molding machine to the cavity space; and

an active thin film element directly deposited on a flexible substrate which is disposed along the non-flat melt channel upstream of the cavity space,

wherein the active thin film element comprises a heater for heating the flow of molten resin.

11. An apparatus to be used in conjunction with an injection molding machine, the apparatus comprising:

a cavity plate;

a core plate disposed relative to the cavity plate so that the core plate and cavity plate together form a cavity space;

a manifold having formed therein an inlet passage for receiving a flow of molten resin from a nozzle of the injection molding machine;

a hot runner nozzle for directing the flow of molten resin from the manifold inlet passage to the cavity space;

a mold gate for regulating the flow of molten resin from the hot runner nozzle to the cavity space, the mold gate together with the hot runner nozzle and the manifold inlet passage defining a non-flat melt channel for directing the flow of molten resin from the nozzle of the injection molding machine to the cavity space; and

a thin film element directly deposited along the non-flat melt channel,

wherein the thin film element comprises a pressure sensor.

12. An apparatus to be used in conjunction with an injection molding machine, the apparatus comprising:

a cavity plate;

a core plate disposed relative to the cavity plate so that the core plate and cavity plate together form a cavity space;

a manifold having formed therein an inlet passage for receiving a flow of molten resin from a nozzle of the injection molding machine;

a hot runner nozzle for directing the flow of molten resin from the manifold inlet passage to the cavity space;

a mold gate for regulating the flow of molten resin from the hot runner nozzle to the cavity space, the mold gate together with the hot runner nozzle and the manifold inlet passage defining a non-flat melt channel for directing the flow of molten resin from the nozzle of the injection molding machine to the cavity space; and

a thin film element directly deposited on a flexible substrate which is disposed along the non-flat melt channel upstream of the cavity space,

wherein the thin film element comprises a thermocouple.

13. An apparatus to be used in conjunction with an injection molding machine, the apparatus comprising:

a cavity plate;

a core plate disposed relative to the cavity plate so that the core plate and cavity plate together form a cavity space;

a manifold having formed therein an inlet passage for receiving a flow of molten resin from a nozzle of the injection molding machine;

a hot runner nozzle for directing the flow of molten resin from the manifold inlet passage to the cavity space;

a mold gate for regulating the flow of molten resin from the hot runner nozzle to the cavity space, the mold gate together with the hot runner nozzle and the manifold inlet passage defining a non-flat melt channel for directing the flow of molten resin from the nozzle of the injection molding machine to the cavity space; and

a thin film element directly deposited along the non-flat melt channel,

wherein the thin film element comprises a gas sensor.

14. An apparatus to be used in conjunction with an injection molding machine, the apparatus comprising:

a cavity plate;

a core plate disposed relative to the cavity plate so that the core plate and cavity plate together form a cavity space;

a manifold having formed therein an inlet passage for receiving a flow of molten resin from a nozzle of the injection molding machine;

a hot runner nozzle for directing the flow of molten resin from the manifold inlet passage to the cavity space;

a mold gate for regulating the flow of molten resin from the hot runner nozzle to the cavity space, the mold gate together with the hot runner nozzle and the manifold inlet passage defining a non-flat melt channel for directing the flow of molten resin from the nozzle of the injection molding machine to the cavity space; and

a thin film element directly deposited along the non-flat melt channel,

wherein the active thin film element comprises an optical guide leakage sensor.

15. An apparatus to be used in conjunction with an injection molding machine, the apparatus comprising:

a mold defining a cavity space;

a manifold having formed therein an inlet passage for flow communication with a nozzle of the injection molding machine;

a hot runner nozzle for flow communication with each of the cavity space and the manifold inlet passage, the hot runner nozzle and the manifold inlet passage together defining a melt channel; and

a plurality of active or passive film elements intermittently disposed along an inside surface of the melt channel upstream of the cavity space and in a position to be in contact with any fluid flowing inside the channel, a portion of each film element in contact with the fluid flowing inside the channel being electrically non-conductive.

16. The apparatus of claim 15, further comprising a passive thin film element disposed adjacent to at least one of the plurality of active thin film elements.

17. An apparatus for directing a flow of molten resin from a nozzle of an injection molding machine to a cavity space defined by a mold, the apparatus comprising:

a manifold having formed therein an inlet passage for receiving the flow of molten resin from the nozzle of the injection molding machine;

a hot runner nozzle for directing the flow of molten resin from the manifold inlet passage to the cavity space, the hot runner injection channel and manifold inlet passage together defining a melt channel; and

an active or passive film element disposed inside of the melt channel upstream of the cavity space and in a location where it will come into contact with molten resin inside the channel, said thin film element comprising a conductive element pattern disposed on a substrate.

18. The apparatus of claim 17, further comprising a passive thin film element disposed adjacent to the active thin film element and in direct contact with the flow of molten resin.

19. The apparatus of claim 17, further comprising a passive thin film element disposed on either side of the active thin film element, one passive thin film element being in direct contact with the flow of molten resin, and the other passive thin film element being sandwiched between the active thin film element and the inner periphery of the melt channel.

20. The apparatus of claim 17, wherein the active thin film element comprises a heater.

21. The apparatus of claim 17, further comprising a thin film electrical insulator disposed adjacent to the heater and in direct contact with the flow of molten resin, and a thin film thermal insulator sandwiched between the heater and the inner periphery of the melt channel.

22. An apparatus for directing a flow of molten resin supplied by an injection molding machine to a cavity space defined by a mold, the apparatus comprising:

a hot runner nozzle including a plurality of melt channels for directing the flow of molten resin supplied by the injection molding machine to the cavity space; and

a plurality of active thin film elements each of which is directly deposited on a flexible, electrically non-conductive substrate disposed substantially adjacent to each melt channel upstream of the cavity space for supplying heat to the flow of molten resin within that melt channel.

23. The apparatus of claim 22, further comprising a control processor for independently controlling the heat supplied by each active thin film element to a corresponding melt channel.

24. An apparatus to be used in conjunction with an injection molding machine, the apparatus comprising:

a cavity plate;

a core plate disposed relative to the cavity plate so that the core plate and cavity plate together form a cavity space;

a hot runner nozzle including a plurality of melt channels, each melt channel directing one of multiple flows of molten resin supplied by the injection molding machine to the cavity space; and

an active thin film element directly deposited on a flexible, electrically non-conductive substrate which is disposed along each melt channel upstream of the cavity space.

25. The apparatus of claim 24, wherein the active thin film element is disposed on the inner periphery of each melt channel.

26. The apparatus of claim 24, further comprising a passive thin film element disposed adjacent to each active thin film element and in direct contact with a respective one of the multiple flows of molten resin.

27. An apparatus for directing multiple flows of molten resin supplied by an injection molding machine to a cavity space, the apparatus comprising:

a mold defining the cavity space;

a manifold;

a hot runner nozzle disposed adjacent to the manifold, the hot runner nozzle and the manifold together defining a plurality of melt channels, each melt channel capable of directing a respective one of the multiple flows of molten resin from the injection molding machine to the cavity space; and

a plurality of active thin film elements each of which is directly deposited on a flexible, electrically non-conductive substrate disposed along at least one of the plurality of melt channels upstream of the cavity space.

28. An injection apparatus to form molded articles in a mold cavity, comprising:

a mold manifold having a plurality of conduits to guide a molten material toward the mold cavity;

a first electrical film heater located adjacent at least one of the conduits to maintain the molten material in a predetermined molding temperature range;

a nozzle coupled to said mold manifold and having at least one nozzle conduit to guide said molten material toward the mold cavity;

a second electrical thin film heater located adjacent said nozzle conduit to maintain the molten material within the predetermined molten temperature range, said second electrical heater being directly deposited inside the nozzle conduit to contact molten resin within the nozzle conduit;

a nozzle tip coupled to the nozzle and having at least one tip conduit in fluid communication with the nozzle conduit;

a mold gate in fluid communication with the nozzle tip conduit and with the mold cavity;

wherein at least one of said first and second electrical film heaters includes (i) an insulation layer in contact with said at least one of the conduits and the nozzle conduit, and (ii) an electrically resistive layer disposed on said insulation layer and having a thickness of greater than zero and less than substantially 0.5 mm.

29. Apparatus according to claim 28, further comprising a third electrical film heater disposed adjacent said nozzle tip.

30. Apparatus according to claim 28, further comprising a third electrical film heater disposed adjacent the mold gate.

31. Apparatus according to claim 28, wherein the electrical insulation layer of at least one of said first and second electrical film heaters comprises a deposition layer.

32. Apparatus according to claim 28, wherein the electrically resistive layer of at least one of said first and second electrical film heaters comprises a non-flat portion.

33. Apparatus according to claim 28, further comprising an electrical film temperature sensor disposed adjacent one of said manifold, said nozzle, and said mold gate, wherein said sensor comprises an insulation layer and an electrical resistive deposition layer disposed on said insulation layer.

34. Apparatus according to claim 28, wherein the electrically resistive layer of at least one of said first and second electrical film heaters comprises an electrically resistive pattern.

35. An injection molding system comprising:

a manifold having a plurality of conduits to distribute a flow of molten material toward a mold cavity;

a nozzle in fluid communication with said manifold and having a head, a body, a tip, and at least one nozzle conduit which guides the molten material toward the mold cavity;

a mold gate disposed adjacent the nozzle and having a gate orifice but conducts the molten material from the nozzle conduit to the cavity space;

gating means to gate the molten material from the nozzle conduit to the cavity space;

means to cool the gate orifice;

a flexible band substrate disposed on an outside of said nozzle conduit and being biased in an inward direction, said flexible band having two ends disposed parallel to said nozzle conduit;

a film electrical heater deposited on said nozzle conduit to stabilize a temperature profile of the molten material, said film electrical heater comprising a patterned heating element extending only partially around a circumference of said nozzle conduit.

36. A system according to claim 35, wherein said gating means comprises a movable valve.

37. A system according to claim 35, wherein said gating means comprises apparatus for sequentially heating and cooling said gate orifice.

38. An injection molding system comprising:

a manifold having a plurality of conduits to distribute a flow of molten material toward a mold cavity;

a nozzle in fluid communication with said manifold and having a head, a body, a tip, and at least one nozzle conduit which guides the molten material toward the mold cavity;

a mold gate disposed adjacent the nozzle and having a gate orifice but conducts the molten material from the nozzle conduit to the cavity space;

gating means to gate the molten material from the nozzle conduit to the cavity space;

means to cool the gate orifice; and

a deposition electrical heater deposited on at least one of said manifold conduit, said nozzle conduit and said gate orifice to stabilize a temperature profile of the molten material,

further comprising a thin film deposition electrical temperature sensor directly deposited on said nozzle conduit.

39. Injection molding apparatus comprising:

an injection nozzle;

a conduit inside the nozzle;

a mold gate insert disposed between said nozzle and a mold cavity space;

gating means for gating molten material from the mold gate insert orifice and the cavity space;

means for cooling the mold gate orifice; and

a thin film deposition layer directly deposited on said nozzle conduit, said deposition layer being electrically resistive to generate heat,

further comprising a second thin film deposition layer directly deposited on said nozzle conduit, said second deposition layer comprising a temperature sensor.