JP2006007421A - Mold for molding hollow molded product and molding method - Google Patents

Mold for molding hollow molded product and molding method Download PDF

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JP2006007421A
JP2006007421A JP2004183218A JP2004183218A JP2006007421A JP 2006007421 A JP2006007421 A JP 2006007421A JP 2004183218 A JP2004183218 A JP 2004183218A JP 2004183218 A JP2004183218 A JP 2004183218A JP 2006007421 A JP2006007421 A JP 2006007421A
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gas
cavity
molded product
hollow molded
molten resin
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Katsuhito Fukushima
勝仁 福島
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Meiki Seisakusho KK
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Meiki Seisakusho KK
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold for molding a hollow molded product constituted so as not only to employ a different molding method of the hollow molded product because a silver streak or the like is easy to occur in the hollow molded product when the hollow molded product is molded by injecting gas in a cavity together with a molten resin through a runner and a gate but also to close the communication hole with the hollow part of the hollow molded product because a defective product is formed when plating or the like if there is the communication hole with the hollow part of the hollow molded product, and also to provide a molding method using the mold. <P>SOLUTION: In the molding method of the hollow molded product P by the injection of the gas G in the molten resin M, which is injected in the cavity 16 formed between a fixed mold 12 and a movable mold 13, from a gas passing port 18a, the gas G is directly injected in the molten resin M, which is injected in the cavity 16 from the gas passing port 18a to form the hollow part P1 and discharged from the gas passing port 18a with the advance of the cooling and solidification of the molten resin M and the communication of the gas passing port 18a and the hollow part P1 is closed by a part of the molten resin M injected in the cavity. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、固定金型と可動金型の間に形成されるキャビティに射出された溶融樹脂にガスを注入する中空成形品の成形金型および成形方法に関し、特には中空成形品の中空部に連通する連通孔を閉塞することのできる中空成形品の成形金型および成形方法に関する。   The present invention relates to a molding die and a molding method for a hollow molded product in which a gas is injected into a molten resin injected into a cavity formed between a fixed mold and a movable mold, and particularly to a hollow portion of the hollow molded product. The present invention relates to a molding die and a molding method for a hollow molded product capable of closing a communicating hole.

固定金型と可動金型の間に形成されるキャビティに射出された溶融樹脂にガスを注入する中空成形品の成形方法は、厚肉製品のヒケ防止、成形時間短縮、および成形材料の節約等の目的から広く行われている。前記中空成形品の成形方法では、一般にガスを注入し中空部を形成した際の連通孔が成形後も残る。前記連通孔は、中空成形品の外観に問題を残すばかりか、特に後工程で中空成形品を液槽に含浸させてメッキや塗装を行う場合には、連通孔から中空部内部にメッキ液や塗料が入り込み、不良品が発生するという問題があった。   The molding method for hollow molded products, in which gas is injected into the molten resin injected into the cavity formed between the fixed mold and movable mold, prevents sinking of thick products, shortens molding time, and saves molding materials. It is widely performed for the purpose of. In the molding method of the hollow molded article, generally, a communication hole is left after molding after gas is injected to form a hollow portion. The communication hole not only leaves a problem in the appearance of the hollow molded product, but particularly when the hollow molded product is impregnated in a liquid tank in the subsequent process to perform plating or coating, a plating solution or the like is introduced into the hollow portion from the communication hole. There was a problem that the paint entered and defective products were generated.

中空成形品に連通孔が残る問題を解決するものとして特許文献1ないし特許文献3に記載されたものが公知である。前記特許文献1ないし特許文献3に記載されたものは、いずれも、キャビティ内にガス通気口が設けられておらず、溶融樹脂とガスをノズル部からランナおよびゲートを介してキャビティ内に射出する。そしてキャビティ内において前記溶融樹脂を冷却固化している際にゲート部分において貯留された一部の溶融樹脂を押出して中空成形品の連通孔を閉塞する。しかし特許文献1ないし特許文献3においては、次のような問題があった。
(1)溶融樹脂とガスをランナおよびゲートを介してキャビティ内に射出するので、射出時に最初にキャビティ内に射出される樹脂がガスを含んでおり、シルバーストリークやボイドといった成形不良が起きやすい。
(2)ガス通気口がキャビティから離れており、キャビティ内に形成された中空部に高圧のガスを及ぼしにくく、また前記ガスの圧抜きも行いにくい。
(3)ゲートの断面積を所定以上の断面積にする必要がある。
Patent Documents 1 to 3 are known to solve the problem of communication holes remaining in a hollow molded product. None of the devices described in Patent Document 1 to Patent Document 3 are provided with a gas vent in the cavity, and inject molten resin and gas from the nozzle portion into the cavity via the runner and gate. . When the molten resin is cooled and solidified in the cavity, a part of the molten resin stored in the gate portion is extruded to close the communication hole of the hollow molded product. However, Patent Documents 1 to 3 have the following problems.
(1) Since the molten resin and gas are injected into the cavity through the runner and gate, the resin first injected into the cavity at the time of injection contains gas, and molding defects such as silver streaks and voids are likely to occur.
(2) The gas vent is separated from the cavity, and it is difficult for high-pressure gas to be exerted on the hollow portion formed in the cavity, and it is difficult to depressurize the gas.
(3) The cross-sectional area of the gate needs to be a predetermined cross-sectional area.

特開平9−216246号公報(請求項1、図5)Japanese Patent Laid-Open No. 9-216246 (Claim 1, FIG. 5) 特開平9−327840号公報(請求項1、図5)JP-A-9-327840 (Claim 1, FIG. 5) 特開平7−100854号公報(請求項1、図2)Japanese Patent Laid-Open No. 7-100854 (Claim 1, FIG. 2)

そこで本発明では、固定金型と可動金型の間に形成されるキャビティに、ランナとゲートを介して溶融樹脂とともにガスを注入して中空成形品を成形する場合には、中空成形品にシルバーストリークやボイドが発生しやすいので、前記とは異なる中空成形品の成形金型および成形方法を提供するとともに、その際に中空成形品の中空部に連通する連通孔があると外観上の問題やメッキや塗装を行う場合に不良品が発生するので、中空部に連通する連通孔を閉塞することのできる中空成形品の成形金型および成形方法を提供することを目的とする。   Therefore, in the present invention, when a hollow molded product is molded by injecting a gas together with a molten resin through a runner and a gate into a cavity formed between a fixed mold and a movable mold, the hollow molded product is silver. Since streaks and voids are likely to occur, it is possible to provide a molding die and a molding method for a hollow molded product different from the above, and if there is a communication hole communicating with the hollow portion of the hollow molded product, It is an object of the present invention to provide a mold for molding a hollow molded product and a molding method capable of closing a communication hole communicating with a hollow portion because defective products are generated when plating or painting is performed.

本発明の請求項1に記載の中空成形品の成形金型は、固定金型と可動金型の間に形成されるキャビティに射出された溶融樹脂にガスを注入する中空成形品の成形金型において、少なくともガス注入時にキャビティ内に位置するガス通気口と、ガス通気口の近傍に形成される樹脂溜まり部と、樹脂溜まり部の溶融樹脂をキャビティ内に向けて押出する押出機構と、を備えたことを特徴とする。   According to a first aspect of the present invention, there is provided a molding die for a hollow molded product in which a gas is injected into a molten resin injected into a cavity formed between a fixed die and a movable die. A gas vent located in the cavity at least during gas injection, a resin reservoir formed in the vicinity of the gas vent, and an extrusion mechanism for extruding the molten resin in the resin reservoir into the cavity. It is characterized by that.

本発明の請求項2に記載の中空成形品の成形金型は、請求項1において、ガス通気口はガスノズルピンの先端に形成され、ガスノズルピンの周囲にはキャビティ形成面に対して凹状に形成された樹脂溜まり部が設けられ、樹脂溜まり部の少なくとも一部は押出機構の面であることを特徴とする。   According to a second aspect of the present invention, there is provided a molding die for a hollow molded article according to the first aspect, wherein the gas vent is formed at the tip of the gas nozzle pin, and is formed around the gas nozzle pin in a concave shape with respect to the cavity forming surface. The resin reservoir portion is provided, and at least a part of the resin reservoir portion is a surface of the extrusion mechanism.

本発明の請求項3に記載の中空成形品の成形方法は、固定金型と可動金型の間に形成されるキャビティに射出された溶融樹脂にガス通気口からガスを注入する中空成形品の成形方法において、キャビティに射出された溶融樹脂にガス通気口からガスを直接注入して中空部を形成し、溶融樹脂の冷却固化の進行とともにガス通気口からガスを排出し、キャビティ内に射出された溶融樹脂の一部によりガス通気口と中空部との連通を閉塞させることを特徴とする。   According to a third aspect of the present invention, there is provided a method for forming a hollow molded article, wherein a gas is injected from a gas vent into a molten resin injected into a cavity formed between a fixed mold and a movable mold. In the molding method, gas is directly injected from the gas vent into the molten resin injected into the cavity to form a hollow portion, and the gas is discharged from the gas vent with the progress of cooling and solidification of the molten resin, and injected into the cavity. Further, the communication between the gas vent and the hollow portion is blocked by a part of the molten resin.

本発明の中空成形品の成形方法は、キャビティ内に射出された溶融樹脂にガス通気口からガスを直接注入して中空部を形成し、溶融樹脂の冷却固化の進行とともにガス通気口からガスを排出し、キャビティ内に射出された溶融樹脂の一部によりガス通気口と中空部との連通を閉塞させるので、従来の固定金型と可動金型の間に形成されるキャビティに、ランナとゲートを介して溶融樹脂とともにガスを注入して中空成形品を成形し、前記中空成形品の中空部に連通する連通孔を閉塞する成形方法と比較して、中空成形品にシルバーストリークやボイドといった不良が発生しにくく、また中空成形品に及ぼすガス圧の制御が容易であるといった効果を有する。また本発明の中空成形品の成形金型についても同様の効果を有する。   According to the method for molding a hollow molded product of the present invention, a gas is directly injected into a molten resin injected into a cavity from a gas vent to form a hollow portion, and the gas is vented from the gas vent with the progress of cooling and solidification of the molten resin. Since the gas vent and the hollow part are blocked by a part of the molten resin discharged and injected into the cavity, the runner and gate are formed in the cavity formed between the conventional fixed mold and the movable mold. Compared with a molding method in which a gas is injected together with molten resin to form a hollow molded product and the communication hole communicating with the hollow portion of the hollow molded product is closed, the hollow molded product has defects such as silver streaks and voids. Are less likely to occur, and the gas pressure exerted on the hollow molded article can be easily controlled. Also, the same effect is obtained with the molding die of the hollow molded product of the present invention.

本発明の実施形態について図1ないし図5を参照して説明する。図1は、本実施形態における中空成形品の成形金型の断面図である。図2ないし図5は、本実施形態における中空成形品の成形方法を示す成形金型の断面図である。   An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a molding die for a hollow molded product in the present embodiment. 2 to 5 are cross-sectional views of a molding die showing a method for molding a hollow molded product in the present embodiment.

中空成形品の成形金型11の概略について図1ないし図5により説明すると、成形金型11は、図示しない射出成形機の固定盤に取付けられる固定金型12と、可動盤に取付けられる可動金型13とからなっている。そして前記固定金型12と可動金型13にはそれぞれキャビティ形成面14,15が対向して形成されている。そして可動金型13が取付けられた可動盤を固定金型12が取付けられた固定盤に向けて移動させ型閉した際に、前記固定金型12のキャビティ形成面14と可動金型13のキャビティ形成面15の間にキャビティ16が形成されるようになっている。また固定金型12には、図示しない射出装置のノズルが当接されるスプルブッシュ17が配設されている。よってノズルとキャビティ16は、スプルブッシュ17の内孔であるスプル部17aおよびゲート部17bを介して連通されるようになっている。   The outline of the molding die 11 of the hollow molding product will be described with reference to FIGS. 1 to 5. The molding die 11 includes a stationary die 12 attached to a stationary platen of an injection molding machine (not shown) and a movable die attached to the movable platen. It consists of a mold 13. Cavity forming surfaces 14 and 15 are formed on the fixed mold 12 and the movable mold 13 to face each other. When the movable platen to which the movable mold 13 is attached is moved toward the fixed platen to which the fixed die 12 is attached and the die is closed, the cavity forming surface 14 of the fixed die 12 and the cavity of the movable die 13 are used. A cavity 16 is formed between the forming surfaces 15. Further, the fixed mold 12 is provided with a sprue bush 17 with which a nozzle of an injection device (not shown) is brought into contact. Therefore, the nozzle and the cavity 16 are communicated with each other through the sprue portion 17a and the gate portion 17b, which are inner holes of the sprue bush 17.

固定金型12におけるゲート部17bの近傍のキャビティ形成面14には、前記ノズルおよびスプルブッシュ17を介さずに不活性ガスをキャビティ16内に直接注入可能なガス供給機構が配設されている。そしてガス供給機構のガスノズルピン18は、キャビティ形成面14よりも可動金型13側に向けて突出して固定されている。ガスノズルピン18の先端には、溶融樹脂Mの流動方向と直交する方向に長手方向を有する幅20μmないし40μmのスリット状のガス通気口18aが形成されている。そして前記ガス通気口18aは、ガスノズルピン18の内部の連通孔18bと固定金型本体部19の連通孔19aを介して金型外部のガス供給・排出装置20に接続されている。ガス供給・排出装置20は、不活性ガスを前記キャビティ16内に注入・排出するためのバルブ、コンプレッサ、およびガスタンク等からなっている。また前記ガスノズルピン18は、図示しない超音波による振動機構によって振動可能となっている。   A gas supply mechanism capable of directly injecting an inert gas into the cavity 16 without using the nozzle and the sprue bush 17 is disposed on the cavity forming surface 14 in the vicinity of the gate portion 17 b in the fixed mold 12. The gas nozzle pin 18 of the gas supply mechanism is fixed so as to protrude from the cavity forming surface 14 toward the movable mold 13 side. At the tip of the gas nozzle pin 18, a slit-like gas vent 18 a having a width direction of 20 μm to 40 μm having a longitudinal direction in a direction orthogonal to the flow direction of the molten resin M is formed. The gas vent 18 a is connected to a gas supply / discharge device 20 outside the mold through a communication hole 18 b inside the gas nozzle pin 18 and a communication hole 19 a in the stationary mold main body 19. The gas supply / discharge device 20 is composed of a valve, a compressor, a gas tank, and the like for injecting and discharging an inert gas into the cavity 16. The gas nozzle pin 18 can be vibrated by an ultrasonic vibration mechanism (not shown).

キャビティ形成面14における前記ガスノズルピン18の周囲の部分は、他のキャビティ形成面14に対して凹状の樹脂溜まり部21となっており、射出された溶融樹脂Mが前記樹脂溜まり部21にも充填されるようになっている。またガスノズルピン18の周囲には前記樹脂溜まり部21の溶融樹脂Mをキャビティ16内に向けて押出する押出機構を構成するスリーブ22が配設されている。スリーブ22のキャビティ側部分の外径は、前記樹脂溜まり部21の内径に嵌合されるように形成され、スリーブ22のキャビティ側部分の内径は前記ガスノズルピン18にスリーブ22が略隙間なく挿通されるように形成されている。そしてスリーブ22の前端面22aは、樹脂溜まり部21の底面を形成している。またスリーブ22の後方部分は、前方の樹脂溜まり部21に挿通されるキャビティ側部分よりも大径に形成され、固定金型本体部19内の空所に収納されている。更にスリーブ22の後端面22bは、同じく固定金型本体部19内に配設された押出機構の油圧シリンダ23のロッドに固定されている。よってスリーブ22は、油圧シリンダ23を駆動させることにより、ガスノズルピン18および樹脂溜まり部21を形成する側面21aに対して所定距離だけ進退移動可能となっている。   A portion around the gas nozzle pin 18 in the cavity forming surface 14 is a concave resin reservoir 21 with respect to the other cavity forming surface 14, and the injected molten resin M is also filled in the resin reservoir 21. It has come to be. Around the gas nozzle pin 18, a sleeve 22 constituting an extrusion mechanism for extruding the molten resin M in the resin reservoir portion 21 into the cavity 16 is disposed. The outer diameter of the cavity side portion of the sleeve 22 is formed so as to be fitted to the inner diameter of the resin reservoir portion 21, and the inner diameter of the cavity side portion of the sleeve 22 is inserted through the gas nozzle pin 18 without a substantial gap. It is formed so that. The front end surface 22 a of the sleeve 22 forms the bottom surface of the resin reservoir 21. Further, the rear portion of the sleeve 22 is formed to have a larger diameter than the cavity-side portion inserted through the front resin reservoir portion 21 and is accommodated in a space in the fixed mold main body portion 19. Further, the rear end surface 22 b of the sleeve 22 is fixed to the rod of the hydraulic cylinder 23 of the extrusion mechanism that is also disposed in the fixed mold main body 19. Therefore, the sleeve 22 can move forward and backward by a predetermined distance with respect to the side surface 21 a forming the gas nozzle pin 18 and the resin reservoir portion 21 by driving the hydraulic cylinder 23.

次に本実施形態の中空成形品の成形方法について図2ないし図5により説明する。まず固定金型12に対して可動金型13が当接され、それらの間にキャビティ16が形成されると、図示しない射出装置のノズルからスプル部17aおよびゲート部17bを介して、前記樹脂溜まり部21を含むキャビティ16に不活性ガスを含まない溶融樹脂Mが射出される(図2)。本実施形態に用いられる樹脂は、熱可塑性樹脂であり、中でもポリプロピレンが好適に用いられる。そして射出された溶融樹脂Mがキャビティ16内のガスノズルピン18の部分を通過した後に、ガス通気口18aから溶融樹脂Mの内部に不活性ガス(窒素ガスG)が15MPaないし30MPaの圧力で注入される(図3)。よって本実施形態では射出装置からの保圧によるキャビティ16内への溶融樹脂Mの充填はほとんど行われない。そして射出された溶融樹脂Mがキャビティ形成面14,15と接触して冷却固化が進行し、ほぼ収縮しない状態となると、前記ガス通気口18aから窒素ガスGを排出する。本実施形態では排出された窒素ガスGは大気中に排出されるが、再度ガス供給・排出装置20のタンクに貯留しリサイクルするようにしてもよい。そしてこの段階ではキャビティ16内において冷却固化されつつある中空成形品Pの中空部P1とガス通気口18aとはまだ連通された状態にある(図4)。なお本実施形態では、ガス通気口18aが直接キャビティ16内に臨んでいるため、ガス通気口がキャビティ内にないものと比較して不活性ガス注入時の昇圧制御や排出時の降圧制御が容易に行える。   Next, a method for forming a hollow molded product according to the present embodiment will be described with reference to FIGS. First, when the movable mold 13 is brought into contact with the fixed mold 12 and a cavity 16 is formed between them, the resin reservoir is obtained from a nozzle of an injection device (not shown) through a sprue portion 17a and a gate portion 17b. Molten resin M not containing an inert gas is injected into the cavity 16 including the portion 21 (FIG. 2). The resin used in the present embodiment is a thermoplastic resin, and among them, polypropylene is preferably used. After the injected molten resin M passes through the portion of the gas nozzle pin 18 in the cavity 16, an inert gas (nitrogen gas G) is injected into the molten resin M through the gas vent 18a at a pressure of 15 MPa to 30 MPa. (FIG. 3). Therefore, in this embodiment, the molten resin M is hardly filled into the cavity 16 by the holding pressure from the injection device. Then, when the injected molten resin M comes into contact with the cavity forming surfaces 14 and 15 and the cooling and solidification progresses and the resin does not substantially contract, the nitrogen gas G is discharged from the gas vent 18a. In the present embodiment, the discharged nitrogen gas G is discharged into the atmosphere, but may be stored again in the tank of the gas supply / discharge device 20 and recycled. At this stage, the hollow portion P1 of the hollow molded product P that is being cooled and solidified in the cavity 16 is still in communication with the gas vent 18a (FIG. 4). In the present embodiment, since the gas vent 18a directly faces the cavity 16, it is easy to perform pressure increase control during inert gas injection and pressure decrease control during discharge as compared with the case where the gas vent is not in the cavity. Can be done.

前記と平行してキャビティ16内への溶融樹脂Mの射出開始から、キャビティ形成面14,15に接触した溶融樹脂Mの冷却固化が進行し、注入された窒素ガスGが排出されるまでの間、ガスノズルピン18は図示しない振動機構によって振動する。よって樹脂溜まり部21内の溶融樹脂Mは、樹脂溜まり部21内に位置して配設されたガスノズルピン18から振動が付与され、固化の進行が遅れた状態にある。そして図4のようにガス通気口18aから窒素ガスGが排出されると、押出機構の油圧シリンダ23を作動させ、スリーブ22を前進させることにより、樹脂溜まり部21の溶融樹脂Mをキャビティ16に臨むガスノズルピン18のガス通気口18aの前方に圧送する。そして前記溶融樹脂Mにより、前記中空成形品Pの中空部P1とガス通気口18aとの連通が閉塞される。その後前記連通を閉塞した溶融樹脂Mの冷却固化が完了すると、可動金型13の型開きがなされ、図示しないエジェクタにより突出されて、中空部P1に対して連通孔のない中空成形品Pが取出される。なお前記中空成形品Pにおける連通孔を閉鎖した部分は、目視した場合に他の部分とは判別可能な状態のままであるが、製品の裏面の目立たない場所なのでほとんど問題がない。そして中空成形品Pは次工程のメッキ工程等に送られる。   In parallel with the above, from the start of injection of the molten resin M into the cavity 16 until the cooling and solidification of the molten resin M in contact with the cavity forming surfaces 14 and 15 proceeds and the injected nitrogen gas G is discharged. The gas nozzle pin 18 vibrates by a vibration mechanism (not shown). Therefore, the molten resin M in the resin reservoir 21 is in a state where the vibration is applied from the gas nozzle pin 18 disposed in the resin reservoir 21 and the progress of solidification is delayed. When the nitrogen gas G is discharged from the gas vent 18a as shown in FIG. 4, the hydraulic cylinder 23 of the extrusion mechanism is operated and the sleeve 22 is advanced, so that the molten resin M in the resin reservoir 21 is transferred to the cavity 16. The gas nozzle pin 18 that faces it is pumped forward of the gas vent 18a. The molten resin M blocks the communication between the hollow portion P1 of the hollow molded product P and the gas vent 18a. Thereafter, when the cooling and solidification of the molten resin M with the communication closed is completed, the movable mold 13 is opened and protruded by an ejector (not shown) to take out a hollow molded product P having no communication hole with respect to the hollow portion P1. Is done. In addition, although the part which closed the communicating hole in the said hollow molded product P remains in the state which can be discriminate | determined from another part when visually observed, since it is a place where the back surface of a product is not conspicuous, there is almost no problem. The hollow molded product P is sent to the next plating step or the like.

なお本実施形態ではガスノズルピン18を含むガス供給機構については、固定金型12に配設される例を説明したが、固定金型と可動金型の少なくとも一方に配設されるものであればよい。また一のキャビティに形成されるガス供給機構の数についても限定されるものではなく、一例としてバンパー成形金型の場合は複数のガス供給機構が配設される。そして本実施形態では樹脂溜まり部21の溶融樹脂Mの固化を遅らせるために、ガスノズルピン18を交番振動により振動させるが、樹脂溜まり部を形成する側面やスリーブ(押出ピン)等、樹脂溜まり部のいずれかの面を振動させるものでもよい。また振動機構は超音波または機械的に振動を付与させるものである。またガスノズルピンおよび樹脂溜まり部を形成する側面の少なくとも一方を、ヒータにより加熱、または媒体流路に高温流動媒体を流して加熱し、他のキャビティ形成面よりも高温にし、樹脂溜まり部の溶融樹脂の冷却固化を遅らせるようにしてもよい。更にはガスノズルピンについては、ガス注入・排出時のみキャビティ内に突出し、中空部とガス通気口の連通を閉塞するときにはキャビティ形成面から後退するものでもよい。そしてガス通気口の形状は、溶融樹脂が進入せずにガスのみが流通するものであれば、円形であってもよく、ガス通気口の位置もガスノズルピンの先端でなくてもよい。   In the present embodiment, the gas supply mechanism including the gas nozzle pin 18 has been described as being disposed in the fixed mold 12. However, as long as it is disposed in at least one of the fixed mold and the movable mold. Good. Also, the number of gas supply mechanisms formed in one cavity is not limited. For example, in the case of a bumper mold, a plurality of gas supply mechanisms are provided. In this embodiment, in order to delay the solidification of the molten resin M in the resin reservoir portion 21, the gas nozzle pin 18 is vibrated by alternating vibration. However, the side surface of the resin reservoir portion and the sleeve (extrusion pin), etc. Any one of the surfaces may be vibrated. Further, the vibration mechanism applies vibrations ultrasonically or mechanically. Further, at least one of the side surfaces forming the gas nozzle pin and the resin reservoir is heated by a heater or heated by flowing a high-temperature fluid medium in the medium flow path to be heated to a temperature higher than the other cavity forming surface, and the molten resin in the resin reservoir You may make it delay cooling solidification of. Further, the gas nozzle pin may protrude into the cavity only at the time of gas injection / discharge, and retreat from the cavity forming surface when the communication between the hollow portion and the gas vent is closed. The shape of the gas vent may be circular as long as the molten resin does not enter and only gas flows, and the position of the gas vent may not be the tip of the gas nozzle pin.

更にまた、樹脂溜まり部は、ガス通気口の近傍に形成されていればよく、例えば固定金型側にガス通気口を有するガスノズルピンを配設し、対向する可動金型側のキャビティ形成面に樹脂溜まり部および押出機構を配設してもよい。そしてスリーブ22の前進ストロークは、キャビティ形成面14と略同一高さまでスリーブ22の前端面22aを前進させるものに限定されず、油圧シリンダ23により前進ストロークを調節可能としてもよい。また樹脂溜まり部21の底面は、すべてスリーブ22の前端面22aである場合に限らず、樹脂溜まり部の少なくとも一部が押出機構の面を構成していればよい。そして成形品Pにおける連通孔の部分は、図5のように中空部P1がなくなるように溶融樹脂Mにより閉塞されるものでも、連通孔のみが閉塞され中空部P1が残るものでもよい。   Furthermore, the resin reservoir only needs to be formed in the vicinity of the gas vent. For example, a gas nozzle pin having a gas vent is provided on the fixed mold side, and the cavity forming surface on the opposite movable mold side is disposed. A resin reservoir and an extrusion mechanism may be provided. The forward stroke of the sleeve 22 is not limited to the forward stroke of the front end surface 22a of the sleeve 22 up to substantially the same height as the cavity forming surface 14, and the forward stroke may be adjusted by the hydraulic cylinder 23. The bottom surface of the resin reservoir portion 21 is not limited to the front end surface 22a of the sleeve 22, and it is sufficient that at least a part of the resin reservoir portion constitutes the surface of the extrusion mechanism. And the part of the communicating hole in the molded product P may be closed by the molten resin M so that the hollow part P1 disappears as shown in FIG. 5, or only the communicating hole may be closed and the hollow part P1 may remain.

また本発明については、一々列挙はしないが、上記した実施形態のものに限定されず、当業者が本発明の趣旨を踏まえて変更を加えたものについても、適用されることは言うまでもない。   The present invention is not enumerated one by one, but is not limited to the above-described embodiment, and it goes without saying that the present invention can be applied to those modified by a person skilled in the art based on the gist of the present invention.

本実施形態における中空成形品の成形金型の断面図である。It is sectional drawing of the shaping die of the hollow molded product in this embodiment. 本実施形態における中空成形品の成形方法を示す成形金型の断面図であってキャビティ内に溶融樹脂を射出した状態を示す。It is sectional drawing of the shaping die which shows the shaping | molding method of the hollow molded product in this embodiment, Comprising: The state which injected the molten resin in the cavity is shown. 本実施形態における中空成形品の成形方法を示す成形金型の断面図であってキャビティ内の溶融樹脂にガスを注入した状態を示す。It is sectional drawing of the shaping die which shows the shaping | molding method of the hollow molded product in this embodiment, Comprising: The state which inject | poured gas into the molten resin in a cavity is shown. 本実施形態における中空成形品の成形方法を示す成形金型の断面図であってガスを排出した状態を示す。It is sectional drawing of the shaping die which shows the shaping | molding method of the hollow molded product in this embodiment, and shows the state which discharged | emitted gas. 本実施形態における中空成形品の成形方法を示す成形金型の断面図であってガス通気口と中空部の連通を閉塞した状態を示す。It is sectional drawing of the shaping die which shows the shaping | molding method of the hollow molded product in this embodiment, Comprising: The state which obstruct | occluded communication of a gas vent and a hollow part is shown.

符号の説明Explanation of symbols

11 成形金型
12 固定金型
13 可動金型
14,15 キャビティ形成面
16 キャビティ
17 スプルブッシュ
17a スプル部
17b ゲート部
18 ガスノズルピン
18a ガス通気口
18b,19a 連通孔
19 固定金型本体部
20 ガス供給・排出装置
21 樹脂溜まり部
21a 側面
22 スリーブ
22a 前端面
22b 後端面
23 油圧シリンダ
G ガス
M 溶融樹脂
P 中空成形品
P1 中空部
DESCRIPTION OF SYMBOLS 11 Molding die 12 Fixed die 13 Movable die 14,15 Cavity formation surface 16 Cavity 17 Sprue bush 17a Sprue part 17b Gate part 18 Gas nozzle pin 18a Gas ventilation port 18b, 19a Communication hole 19 Fixed mold body part 20 Gas supply -Discharge device 21 Resin reservoir 21a Side surface 22 Sleeve 22a Front end surface 22b Rear end surface 23 Hydraulic cylinder G Gas M Molten resin P Hollow molded product P1 Hollow portion

Claims (3)

固定金型と可動金型の間に形成されるキャビティに射出された溶融樹脂にガスを注入する中空成形品の成形金型において、
少なくともガス注入時にキャビティ内に位置するガス通気口と、
前記ガス通気口の近傍に形成される樹脂溜まり部と、
前記樹脂溜まり部の溶融樹脂をキャビティ内に向けて押出する押出機構と、を備えたことを特徴とする中空成形品の成形金型。
In a mold for hollow molded products in which gas is injected into a molten resin injected into a cavity formed between a fixed mold and a movable mold,
A gas vent located in the cavity at least during gas injection;
A resin reservoir formed in the vicinity of the gas vent;
A molding die for a hollow molded product, comprising: an extrusion mechanism for extruding the molten resin in the resin reservoir portion into the cavity.
前記ガス通気口はガスノズルピンの先端に形成され、
前記ガスノズルピンの周囲にはキャビティ形成面に対して凹状に形成された樹脂溜まり部が設けられ、前記樹脂溜まり部の少なくとも一部は押出機構の面であることを特徴とする請求項1に記載の中空成形品の成形金型。
The gas vent is formed at the tip of a gas nozzle pin,
The resin reservoir part formed in a concave shape with respect to the cavity forming surface is provided around the gas nozzle pin, and at least a part of the resin reservoir part is a surface of an extrusion mechanism. Mold for hollow molded products.
固定金型と可動金型の間に形成されるキャビティに射出された溶融樹脂にガス通気口からガスを注入する中空成形品の成形方法において、
前記キャビティ内に射出された溶融樹脂に前記ガス通気口からガスを直接注入して中空部を形成し、
前記溶融樹脂の冷却固化の進行とともに前記ガス通気口からガスを排出し、
前記キャビティ内に射出された溶融樹脂の一部により前記ガス通気口と前記中空部との連通を閉塞させることを特徴とする中空成形品の成形方法。
In a molding method of a hollow molded product in which gas is injected from a gas vent into a molten resin injected into a cavity formed between a fixed mold and a movable mold,
A gas is directly injected from the gas vent into the molten resin injected into the cavity to form a hollow portion,
As the cooling and solidification of the molten resin proceeds, gas is discharged from the gas vent,
A method for molding a hollow molded article, wherein communication between the gas vent and the hollow portion is blocked by a part of the molten resin injected into the cavity.
JP2004183218A 2004-06-22 2004-06-22 Mold for molding hollow molded product and molding method Pending JP2006007421A (en)

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Family

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Country Status (1)

Country Link
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