IPC분류정보
국가/구분 |
United States(US) Patent
등록
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국제특허분류(IPC7판) |
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출원번호 |
US-0154158
(2002-05-23)
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발명자
/ 주소 |
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대리인 / 주소 |
Reising, Ethington, Barnes, Kisselle, P.C.
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인용정보 |
피인용 횟수 :
4 인용 특허 :
53 |
초록
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An improved injection molding runnerless manifold and nozzle system, method and apparatus in which the fluid plastic molding material transfer conduits, such as the manifold runner channels and cavity injection nozzle passageway, are constructed of a low thermal conductivity, non-metallic heat insul
An improved injection molding runnerless manifold and nozzle system, method and apparatus in which the fluid plastic molding material transfer conduits, such as the manifold runner channels and cavity injection nozzle passageway, are constructed of a low thermal conductivity, non-metallic heat insulation structural material to thereby heat insulate the liquified molding material or resin, whether thermosetting or thermoplastic, while resident in the manifold runners and/or nozzle passageways. The heat transfer and other physical parameters of the conduit material and structure are such that this molding material remains at a reasonable uncured molding temperature while resident in the transfer conduit for the duration of at least one injection cycle due to the heat insulation characteristics of these fluid flow conduits of the system. Preferably the heat insulation material of which the flow conduits are constructed is a polymer material having mechanical properties adequate to permit continuous accessible usage in the foregoing method as part of a separable and clampable manifold and/or nozzle system within the mold tooling as operable in the injection molding environment.
대표청구항
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1. An injection molding method for use with an injection molding machine system characterized by hot or cold runner operable for feeding a liquified plastic molding material to a mold cavity via a manifold, and for maintaining the fluidity of the manifold-resident plastic molding during closure of t
1. An injection molding method for use with an injection molding machine system characterized by hot or cold runner operable for feeding a liquified plastic molding material to a mold cavity via a manifold, and for maintaining the fluidity of the manifold-resident plastic molding during closure of the injection gate, thereby enabling use of the resident molding material in the following molding cycle, said fluidity maintaining method comprising the steps of:(a) providing a flow path for the liquified plastic molding material extending between a manifold inlet sprue, as fed by the injection machine ram of the system, and a mold cavity fed by a cavity-fill nozzle at the outlet of a runner of the system, (b) providing said flow path as a pre-formed mold component mounted in the manifold and containing a flow conduit of high temperature resistant solid material sized to have self supporting structural integrity for flow conducting the pressurized liquified plastic molding material, and (c) constructing said mold component containing said flow conduit of a non-metallic heat insulation material having a sufficiently low thermal conductivity to heat insulate the liquified plastic molding material resident in the conduit flow path such that this plastic molding material remains at a reasonable uncured molding temperature for the duration of at least one injection cycle of the system due to the heat insulation characteristics of the fluid flow conduit of the system. 2. The method of claim 1 wherein the heat insulation material of said conduit is selected to comprise a polymer material having mechanical properties adequate to permit continuous accessible usage as part of the manifold and/or nozzle system within the molding environment of the injection molding machine.3. The method as set forth in claim 2 wherein the material of said flow conduit is selected to be a high temperature polymer material having low thermal conductivity, relatively high compressive strength and rigidity and relatively high wear resistance to the wearing action of molding material in liquid state flowing therethrough under injection molding pressures.4. The method as set forth in claim 3 wherein said high temperature polymer material is selected from the group comprising one or more of the following polymers:(a) a polytetrafluoroethylene compound (b) a polimide material (c) an acetal compound (d) an amorphous thermoplastic polyetherimide material (e) a polyamide-imide material (f) a polybenzamidazole material (g) a composite produced through the chemical vapor deposition or resin char process. 5. The method, set forth in claim 1 wherein said manifold containing said flow path conduit includes a two-piece split manifold plate set comprising an upper manifold plate and a lower manifold plate having mutually facing pockets recessed into complement mating faces of said plates, said pre-formed mold component comprising a polymer runner bar or plate subassembly including complementary upper and lower plates, said bars or plates having mating facing surfaces with runner channel trenches formed into them and registering in assembly to define said conduit flow path and serving as runner means in said manifold plate set.6. The method set forth in claim 5 wherein said polymer bars or plate each comprise a plurality of legs radiating from a common center sprue area and having outlets of the runner channels trenches proximate the distal ends of said legs constructed and arranged for feeding to associated ones of a plurality of said mold cavities in said mold tooling, and wherein said mating facing surfaces of said upper and lower polymer bars each have a shallow V-shape in transverse cross section, one of said surfaces having a positive taper and the other a negative taper designed under squeeze pressure to form mutually engaged sealing surfaces for preventing leakage from said trench channels when mold tooling clamping pressure is applied for closing the mold tooling for molding operation and thereby squeezes together said upper and lower bars.7. The method set forth in claim 5 wherein said polymer bars or plates are dimensioned relative to their respective receiving pockets in said manifold plates such that when the bars or plates are abutted with only light assembly pressure they protrude a slight distance from the corresponding mating faces of said manifold plates so that these manifold plate faces are separated with a slight clearance by such abutment of the polymer bars or plates, the clearance generating protrusion dimension of the bars or plates being taken up by clamping pressure exerted on the mold to bring the manifold plate mating faces into contact, thereby compressing the polymer bars or plates with sufficient pre-load to insure a reliable seal at the polymer bar or plate contiguous mating faces and to thereby insure that the liquefied molding material flowing through the runner channels does not leak or escape through such polymer bar or plate mating faces.8. The method set forth in claim 2 wherein said conduit material is selected from the group consisting of the following polymers:(a) a polytetrafluoroethylene compound (b) a polimide material (c) an acetal compound (d) an amorphous thermoplastic polyetherimide material (e) a polyamide-imide material (f) a polybenzamidazole material (g) a composite produced through the chemical vapor deposition or resin char process. 9. The method set forth in claim 2 wherein the cross sectional thickness of the polymer material forming the walls of the conduit runner flow channels is sized to limit the heat transfer per unit of time sufficient to protect the uncured plastic molding material in its liquid state, regardless of whether it be thermosetting or thermoplastic material, from any inappropriate amounts of heat transfer to or from the material for a period of time at least equal to the time necessary to produce about three complete volume changes in the manifold and nozzle flow path.10. The method set forth in claim 1 wherein the cross sectional thickness of the walls of said flow path conduit in both said manifold and nozzle are sized to provide necessary heat transfer per unit of time to protect the plastic molding material in its liquid state from inappropriate amounts of heat transfer to or from such material for a period of time equal to that necessary to produce at least about three complete volume changes in the manifold and nozzle conduit flow path.11. A mold cavity filling injection nozzle for an injection molding machine comprising conduit means defining an axially extending central flow-through passageway having an outlet for allowing flow of liquefied plastic molding material into a mold cavity of a molding machine, an outlet flap, valve located inside said nozzle at said nozzle passageway outlet in aconical outlet constriction of said flow-through passageway having a flow-fill-direction convergent taper at the flow outlet end of said nozzle, said flap valve comprising a semi-resilient material having at least one very narrow slot therein communicating at an upstream end with said flow passageway and at a downstream end with the exterior of said nozzle, said slot having a length dimension axially of said nozzle greater then its width dimension transverse to the longitudinal axis of said nozzle, said slot having a thickness dimension in a direction perpendicular to the imaginary plane defined by said length and width dimensions on the order of about 0.000010 inches, said slot being thickness enlargeable by the fluid pressure exerted by liquefied plastic injection molding material when present in the said nozzle flow passageway to thereby cause flow opening action in said flap valve in response to said fluid pressure rising to a given predetermined positive value, said flap valve being operably closed by reduction of said fluid pressure to a predetermined minimum positive value or to a negative value, andwherein said nozzle comprises an outer metal shell made from tool steel or other high strength metal alloy and provided with means for removably attaching said nozzle to said manifold, said nozzle having a flow-through interior channel communicating at its inlet end with an outlet of an associated conduit flow path runner in said manifold and at its outlet end with a passage leading to an associated mold cavity in said mold tooling, said outer shell being hollow and formed with a constant diameter bore open at the upper end of the shell and terminating and opening at its lower end at a conical interior shell surface formed by a frustoconical nose section of said shell at the downstream end of said nozzle, said shell nose having a flat end face designed to sealably seat on a corresponding flat surface provided in the associated mold tooling, said nozzle further including high temperature resistant polymer spool means received with a close fit within the inner diameter of the bore of said shell and defining said flow-through passage of said nozzle, said spool being constructed of a high temperature polymer material having low thermal conductivity, relatively high compressive strength and rigidity and relatively high wear resistance to the action of molding material in liquid state flowing therethrough under mold injection pressure. 12. The nozzle as set forth in claim 11 wherein said spool mean of said nozzle comprises a plurality of axially end-abutted laminated spools each differing in material composition from the other, the material composition of each said spool being selected to best meet the heat insulation characteristics most needed in the region occupied by each such spool consistent with the least cost of material.13. The nozzle as set forth in claim 11 wherein said spool means of said nozzle comprises a plurality of axially end-abutted inner spools arrayed in an inner annular layer and a plurality of outer spools in axial end-abutment and arrayed as an outer spool layer concentric with said inner spool layer to thereby form an axial and radial laminate spool construction within said nozzle shell.14. The nozzle as set forth in claim 11 wherein the exterior side surface of said spool means has radially protruding lands engaging the interior surface of said shell to thereby define insulating air gaps in the annular space defined between the spool exterior side surface intermediate an adjacent pair of said lands and the juxtaposed interior surface of said shell.15. The nozzle as set forth in claim 11 wherein said spool means of said nozzle protrudes axially from at least one end of said shell under no-load nozzle assembly conditions such that, when said nozzle is installed in said manifold and said manifold is clamped in assembly with mold tooling and thus in operable assembly with the associated mold tooling components, said spool means protrusion causes sufficient mechanical pre-load to assure that said spool means is axially compressed, thereby causing some radial expansion of said spool means within said shell and thereby assuring that the liquified plastic molding material present in said flow-through passage of said nozzle spool means does not leak or escape from the nozzle conduit flow path or from joint junctions with those associated mold tooling components in end abutment with opposite ends of said nozzle.
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