JPH06304954A - Gas injection molded piece and molding method thereof - Google Patents
Gas injection molded piece and molding method thereofInfo
- Publication number
- JPH06304954A JPH06304954A JP9935093A JP9935093A JPH06304954A JP H06304954 A JPH06304954 A JP H06304954A JP 9935093 A JP9935093 A JP 9935093A JP 9935093 A JP9935093 A JP 9935093A JP H06304954 A JPH06304954 A JP H06304954A
- Authority
- JP
- Japan
- Prior art keywords
- gas
- buffer
- mold
- filling
- molten resin
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/1703—Introducing an auxiliary fluid into the mould
- B29C45/1704—Introducing an auxiliary fluid into the mould the fluid being introduced into the interior of the injected material which is still in a molten state, e.g. for producing hollow articles
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
- Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明はガス射出成形品およびそ
の製造方法に係り、自動車のバンパーやダッシュボード
等の内外装品、あるいは、家電製品のケーシング等の大
型面状製品に利用できる。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas injection molded product and a method for manufacturing the same, and can be used for interior and exterior products such as automobile bumpers and dashboards, or large surface products such as casings for home electric appliances.
【０００２】[0002]
【背景技術】従来より、軽量にして高剛性な成形品が得
られる射出成形方法として、ガス射出成形方法が知られ
ている。この方法では、金型内の主キャビティに溶融樹
脂を充填した後、キャビティ内に加圧窒素ガス等の不活
性ガスを注入して射出成形を行う。充填された溶融樹脂
内には、ガス圧によりガスの流路（以下「ガスチャンネ
ル」という。）が形成され、ガスチャンネル内のガスに
よって押圧された溶融樹脂が金型の内面に向かって押圧
されるため、均一な厚さの薄肉中空成形品の成形が期待
できる。2. Description of the Related Art Conventionally, a gas injection molding method has been known as an injection molding method for obtaining a lightweight and highly rigid molded product. In this method, after injection of a molten resin into the main cavity in the mold, an inert gas such as pressurized nitrogen gas is injected into the cavity for injection molding. A gas flow path (hereinafter referred to as "gas channel") is formed in the filled molten resin by the gas pressure, and the molten resin pressed by the gas in the gas channel is pressed toward the inner surface of the mold. Therefore, it can be expected to form a thin hollow molded product having a uniform thickness.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、ガス射
出成形を連続して行おうとすると、各射出成形毎に樹脂
の充填量が変動する「充填むら」が生じる。この「充填
むら」により溶融樹脂の充填量が増大すると、同一条件
でガス注入を行った場合、ガスチャンネルの末端部分に
までガスを注入することができず、当該末端部分には溶
融樹脂の肉厚が部分的に厚くなった厚肉部分が生じる。
この厚肉部分は、固化するとヒケ等の不良箇所が表面に
発生するので、成形品の外観を損なうものとなる。一
方、前記「充填むら」により溶融樹脂の充填量が減少す
ると、ガスチャンネルの末端部分近傍において、ガスが
溶融樹脂を突き破って外部に流出し、成形品に孔が開
く、あるいは、一般面にガスがリークするなどの不良現
象が生じ、この不良現象により、成形品の外観が損なわ
れる。また、各射出成形の充填量が適切であっても、ガ
ス圧や金型温度等が高すぎると、ガスが当該溶融樹脂の
薄い部分を突き破って孔が開いたり、一般面にガスがリ
ークするなどの不良現象が生じて成形品の外観が損なわ
れる。このため、「充填むら」が生じないように溶融樹
脂の充填量を厳密に制御し、かつ、ガスを注入しても溶
融樹脂に孔が開かないように、ガス圧および金型温度等
を一定に制御する必要があり、これにより、溶融樹脂の
充填量、ガス圧、および、金型温度等の制御が非常に難
しくなり、そのための制御装置が複雑かつ高価なものと
なるという問題がある。However, when the gas injection molding is continuously performed, "filling unevenness" occurs in which the filling amount of the resin varies for each injection molding. If the filling amount of the molten resin increases due to this "filling unevenness", when gas is injected under the same conditions, the gas cannot be injected even to the end portion of the gas channel, and the meat of the molten resin cannot be injected to the end portion. A thick part is formed in which the thickness is partially increased.
When the thick portion is solidified, a defective portion such as a sink mark is generated on the surface, which impairs the appearance of the molded product. On the other hand, when the filling amount of the molten resin decreases due to the "filling unevenness", the gas penetrates the molten resin and flows out to the outside in the vicinity of the end portion of the gas channel, and a hole is formed in the molded product, or the gas is formed on the general surface. Occurs, and the appearance of the molded product is impaired. Further, even if the filling amount of each injection molding is appropriate, if the gas pressure, the mold temperature, etc. are too high, the gas may break through the thin portion of the molten resin to open a hole, or the gas may leak to the general surface. Such a defective phenomenon occurs and the appearance of the molded product is impaired. Therefore, the filling amount of the molten resin is strictly controlled so that “uneven filling” does not occur, and the gas pressure and mold temperature are kept constant so that holes are not opened in the molten resin even if gas is injected. Therefore, it is very difficult to control the filling amount of the molten resin, the gas pressure, the mold temperature, etc., and there is a problem that the control device therefor becomes complicated and expensive.
【０００４】本発明の目的は、ガス射出成形に係る制御
が容易で、かつヒケや孔等の不良箇所を生じさせないガ
ス射出成形品およびその成形方法を提供することにあ
る。An object of the present invention is to provide a gas injection-molded article which is easy to control for gas injection molding and does not cause defects such as sink marks and holes, and a molding method thereof.
【０００５】[0005]
【課題を解決するための手段】本発明の第１発明は、ガ
ス射出成形品であって、内部にガスを注入して形成した
ガスチャンネルを囲む中空厚肉部の末端部分が先細りと
なっていることを特徴とする。The first aspect of the present invention is a gas injection molded article, wherein the end portion of the hollow thick wall portion surrounding the gas channel formed by injecting gas is tapered. It is characterized by being
【０００６】本発明の第２発明は、ガス射出成形方法で
あって、予めキャビティの厚さ寸法を周囲よりも厚くし
たガスチャンネル案内部と、このガスチャンネル案内部
の末端部分を先細りにして形成したバッファ形成部とを
備えた金型に溶融樹脂の充填を開始した後、充填された
溶融樹脂内にガスを注入することを特徴とする。A second aspect of the present invention is a gas injection molding method, in which a gas channel guide portion in which the thickness of the cavity is made thicker than the surroundings and the end portion of the gas channel guide portion is formed by tapering. It is characterized in that after the molten resin is started to be filled in the mold provided with the buffer forming portion, gas is injected into the filled molten resin.
【０００７】[0007]
【作用】このような本発明では、予め金型に備えておい
たバッファ形成部により、ガスチャンネルの末端部分に
は、先細りとなった緩衝部が形成される。ここで、溶融
樹脂の充填量の増加によりガスの注入できる量が減少し
ても、緩衝部は先細りであるため、ガスの圧力により成
形品の表面にはヒケが発生しなくなる。一方、緩衝部の
容量を充分大きく設定しておけば、溶融樹脂の充填量の
減少により注入されるガスの量が増大しても、ガスが緩
衝部の先細り部分を突き破るためには高いガス圧が必要
となるため、ガスが緩衝部を突き破って溶融樹脂に孔を
開けることができなるため、成形品の表面に孔が生じる
等の不良現象の発生が防止されるようになる。従って、
溶融樹脂の充填量、ガス圧、および、金型温度等を厳密
に制御しなくとも、「充填むら」による溶融樹脂の変動
分が緩衝部に吸収され、ヒケや孔等の不良箇所の発生を
未然に防止でき、これにより前記目的が達成される。In the present invention as described above, the tapered buffer portion is formed at the end portion of the gas channel by the buffer forming portion provided in the mold in advance. Here, even if the amount of gas that can be injected decreases due to an increase in the filling amount of the molten resin, since the buffer portion is tapered, sink marks do not occur on the surface of the molded product due to the pressure of the gas. On the other hand, if the volume of the buffer is set large enough, even if the amount of injected gas increases due to the decrease in the filling amount of the molten resin, a high gas pressure is required for the gas to break through the tapered portion of the buffer. Since the gas is required to penetrate through the buffer portion to form holes in the molten resin, it is possible to prevent the occurrence of defective phenomena such as formation of holes on the surface of the molded product. Therefore,
Even if the molten resin filling amount, gas pressure, mold temperature, etc. are not strictly controlled, fluctuations in the molten resin due to "filling unevenness" are absorbed in the buffer section, and defects such as sink marks and holes are not generated. It can be prevented in advance, thereby achieving the above-mentioned object.
【０００８】[0008]
【実施例】以下、本発明の一実施例を図面に基づいて説
明する。図１には、本実施例の金型10の内部に形成され
るキャビティ11の形状が示されている。このキャビティ
11は、厚さが均一となった面状部12と、この面状部12よ
りも厚い寸法の溝状のガスチャンネル案内部13とを有す
るものとなっている。面状部12は、内部に充填された溶
融樹脂を平板状にするものであり、成形品20の平板部22
を成形する部分となっている。ガスチャンネル案内部13
は、キャビティ11の長手方向の中心線に沿って形成さ
れ、内部に充填された溶融樹脂を棒状にするものであ
り、成形品20の中空厚肉部23を成形する部分となってい
る。このガスチャンネル案内部13の内部に溶融樹脂を充
填し、充填された溶融樹脂の内部にガスを注入すること
により、中空厚肉部23と、この中空厚肉部23の内部にガ
スチャンネル24とがガスチャンネル案内部13に沿って形
成されるようになっている。ガスチャンネル案内部13の
一端側にはガスの注入口14が接続され、ガスチャンネル
案内部13の他端側にはその末端部分を先細りにしたバッ
ファ形成部15が設けられている。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the shape of a cavity 11 formed inside the mold 10 of this embodiment. This cavity
The reference numeral 11 has a planar portion 12 having a uniform thickness and a groove-shaped gas channel guide portion 13 having a thickness larger than that of the planar portion 12. The planar portion 12 is for flattening the molten resin filled inside, and is a flat portion 22 of the molded product 20.
Is the part to be molded. Gas channel guide 13
Is formed along the center line in the longitudinal direction of the cavity 11 and has a rod-like shape of the molten resin filled therein, which is a portion for molding the hollow thick portion 23 of the molded product 20. A molten resin is filled inside the gas channel guide portion 13, and a gas is injected into the filled molten resin to form a hollow thick portion 23, and a gas channel 24 inside the hollow thick portion 23. Are formed along the gas channel guide portion 13. A gas inlet 14 is connected to one end of the gas channel guide portion 13, and a buffer forming portion 15 having a tapered end portion is provided on the other end side of the gas channel guide portion 13.
【０００９】バッファ形成部15は、具体的には、図中高
さ寸法Ｈが漸次小さくされて、その断面積が先端に行く
ほど小さくなったものである。このバッファ形成部15に
より、中空厚肉部23の端部分に先細りの緩衝部25が形成
されるようになっている。ここで、バッファ形成部15の
断面積すなわち緩衝部25の断面積の減少率は、ガスの進
入を促進するいわゆる「くさび効果」が得やすいように
小さい値に設定されている。これにより、溶融樹脂の充
填量が増大して、ガスの注入量が減少しても、緩衝部25
の内部に充分な量のガスが注入可能とされ、このガスの
注入により緩衝部25の表面にヒケが生じないようになっ
ている。また、バッファ形成部15の容量すなわち緩衝部
25の容量は、注入されたガスが緩衝部25を突き破って溶
融樹脂に孔を開けることがないように、充分大きく設定
されている。これにより、溶融樹脂の充填量が減少し
て、ガスの注入量が増大しても、ガスが緩衝部25を突き
破ることがなくなり、成形品20の表面に孔が発生しない
ようになっている。なお、緩衝部25は、「充填むら」に
より溶融樹脂の充填量が、ガスチャンネル案内部13の容
積の±０．５％程度変動しても、その変動による変化量
を吸収可能な寸法に設定されている。Specifically, the buffer forming portion 15 is such that the height dimension H in the drawing is gradually reduced, and the cross-sectional area thereof becomes smaller toward the tip. The buffer forming part 15 forms a tapered buffer part 25 at the end of the hollow thick part 23. Here, the reduction rate of the cross-sectional area of the buffer forming portion 15, that is, the cross-sectional area of the buffer portion 25 is set to a small value so that a so-called “wedge effect” that promotes gas intrusion can be easily obtained. As a result, even if the filling amount of the molten resin increases and the gas injection amount decreases, the buffer section 25
A sufficient amount of gas can be injected into the interior of the buffer so that sink marks do not occur on the surface of the buffer section 25 due to the injection of this gas. In addition, the capacity of the buffer forming unit 15, that is, the buffer unit
The volume of 25 is set to be large enough so that the injected gas does not penetrate through the buffer portion 25 to form a hole in the molten resin. As a result, even if the filling amount of the molten resin is decreased and the injection amount of the gas is increased, the gas does not penetrate through the buffer section 25, and no hole is formed on the surface of the molded product 20. It should be noted that the buffer portion 25 is set to a size capable of absorbing the variation amount due to the variation even if the filling amount of the molten resin fluctuates by about ± 0.5% of the volume of the gas channel guide portion 13 due to “uneven filling”. Has been done.
【００１０】このような本実施例では、金型10を射出成
形機にセットし、そのキャビティ11に溶融樹脂を充填
し、充填の開始後または充填の終了後に、金型10に充填
した溶融樹脂内にガスを注入する。そして、このガスの
注入により、ガスチャンネル案内部13に沿ってガスチャ
ンネル24を形成し、ガスチャンネル24内のガス圧を利用
して溶融樹脂の表面を金型10に密着させ、成形品20の表
面からヒケ等の不良箇所の発生を防止する。ここで、ガ
スチャンネル案内部13に設けたバッファ形成部15によっ
て成形される緩衝部25は、「充填むら」等による溶融樹
脂の変動分を吸収するため、溶融樹脂の充填量、ガス
圧、および、金型温度等を厳密に制御する必要がなくな
る。In this embodiment, the mold 10 is set in the injection molding machine, the cavity 11 is filled with the molten resin, and the molten resin filled in the mold 10 is filled after the filling is started or after the filling is completed. Inject gas inside. Then, by injecting this gas, a gas channel 24 is formed along the gas channel guide portion 13, the surface of the molten resin is brought into close contact with the mold 10 by utilizing the gas pressure in the gas channel 24, and the molded product 20 Prevents the occurrence of defects such as sink marks from the surface. Here, since the buffer portion 25 formed by the buffer forming portion 15 provided in the gas channel guide portion 13 absorbs the variation of the molten resin due to "filling unevenness" or the like, the filling amount of the molten resin, the gas pressure, and Therefore, it becomes unnecessary to strictly control the mold temperature and the like.
【００１１】前述のような本実施例によれば、次のよう
な効果が得られる。すなわち、ガスチャンネル案内部13
に設けたバッファ形成部15によって緩衝部25を成形し、
この緩衝部25で、「充填むら」等による溶融樹脂の変動
分を吸収するようにしたので、溶融樹脂の充填量、ガス
圧、および、金型温度等を厳密に制御しなくとも、ヒケ
や孔等の不良箇所の発生を未然に防止できる。According to this embodiment as described above, the following effects can be obtained. That is, the gas channel guide section 13
The buffer portion 25 is formed by the buffer forming portion 15 provided in
Since the buffer portion 25 is configured to absorb the fluctuation of the molten resin due to "filling unevenness" or the like, it is possible to obtain sink marks or the like without strictly controlling the filling amount of the molten resin, the gas pressure, the mold temperature, and the like. It is possible to prevent the occurrence of defective parts such as holes.
【００１２】また、溶融樹脂の充填量、ガス圧、およ
び、金型温度等を厳密に制御しなくても、良好なガス射
出成形が行えるようにしたため、ガス射出成形装置の制
御部を比較的簡単なものとできる。Further, since the good gas injection molding can be performed without strictly controlling the filling amount of the molten resin, the gas pressure, the mold temperature, etc., the control unit of the gas injection molding apparatus is relatively controlled. Can be simple.
【００１３】さらに、ガスチャンネル案内部13の末端部
分に先細りのバッファ形成部15を設けるだけで、緩衝部
25を形成可能としたので、簡単な金型改造で前述の効果
が得られるようになるうえ、ガスチャンネルを有するも
のであれば、バッファ形成部15はあらゆる金型に適用で
きるので、多種多様な成形品についてその成形性を向上
できる。Further, by only providing the tapered buffer forming portion 15 at the end portion of the gas channel guide portion 13, the buffer portion is formed.
Since 25 can be formed, the above effect can be obtained by a simple mold modification, and the buffer forming unit 15 can be applied to any mold as long as it has a gas channel. The moldability of the molded product can be improved.
【００１４】次に、本発明の具体的な効果を以下の実験
例に基づいて説明する。 〔実験例〕本実験例は、本発明の第１実施例に基づいて
ガス射出成形を連続１００回行うものである。金型とし
ては、図１に示したほぼ平板状のキャビティ11を有する
金型10を採用する。射出成形品としては、図２に示され
るように、長方形状の面材であるテストピース30を成形
する。 〔比較例〕本比較例は、従来技術に基づいてガス射出成
形を連続１００回行うものである。金型としては、前記
実験例の金型10からバッファ成形部15を省略したものを
採用する。射出成形品としては、図３に示されるよう
に、緩衝部25がないこと以外は前記実験例と同一形状の
テストピース40を成形する。 〔テストピースの寸法設定〕これらの実験例および比較
例においては、テストピースの寸法を以下のように設定
した（図２および図３参照）。 全長 Ｌ１：４２０ｍｍ 全幅 Ｗ１ Ｗ１：１００ｍｍ 平板部の厚さ Ｔ： ３ｍｍ 中空厚肉部の幅 Ｗ２： ６ｍｍ 中空厚肉部の高さ Ｈ： ５ｍｍ 緩衝部の長さ Ｌ２： ４０ｍｍ（実験例のみ） 〔射出条件〕また、以上の実験例および比較例では、以
下のような射出条件で射出成形を行った。 使用樹脂：ポリプロピレン（出光石油化学（株）製
Ｊ−３０５４Ｈ） 樹脂温度 ： ２２０ ℃ 金型温度 ： ３０ ℃ ガス圧 ： ６ ＭＰａ 射出時間 ： ２ 秒 射出成形機 ：東芝機械（株）製 ＩＳ−２００
ＣＮNext, specific effects of the present invention will be described based on the following experimental examples. [Experimental Example] In this experimental example, gas injection molding is continuously performed 100 times based on the first embodiment of the present invention. As the mold, the mold 10 having the substantially flat plate-shaped cavity 11 shown in FIG. 1 is adopted. As an injection-molded product, as shown in FIG. 2, a test piece 30 which is a rectangular face material is molded. Comparative Example In this comparative example, gas injection molding is continuously performed 100 times based on the conventional technique. As the mold, the mold in which the buffer molding portion 15 is omitted from the mold 10 of the experimental example is adopted. As an injection-molded product, as shown in FIG. 3, a test piece 40 having the same shape as that of the above-described experimental example is molded except that the buffer portion 25 is not provided. [Dimension Setting of Test Piece] In these experimental examples and comparative examples, the dimension of the test piece was set as follows (see FIGS. 2 and 3). Total length L1: 420 mm Total width W1 W1: 100 mm Thickness of flat plate portion T: 3 mm Width of hollow thick portion W2: 6 mm Height of hollow thick portion H: 5 mm Length of buffer portion L2: 40 mm (only for experimental example) [ Injection Conditions] In addition, in the above experimental examples and comparative examples, injection molding was performed under the following injection conditions. Resin used: polypropylene (made by Idemitsu Petrochemical Co., Ltd.)
J-3054H) Resin temperature: 220 ° C Mold temperature: 30 ° C Gas pressure: 6 MPa Injection time: 2 seconds Injection molding machine: Toshiba Machine Co., Ltd. IS-200
CN
【００１５】〔実験結果〕実験例では、得られた全ての
テストピース30には、図４に示されるように、緩衝部25
の内部に達するガスチャンネル24が形成されていた。ま
た、テストピース30の各々について、重量を測定した結
果、最も軽いものが１１４．１ｇ、最も重いものが１１
４．９ｇあり、その平均重量は１１４．６ｇとなった。
一方、ガスチャンネル24の全長を測定した結果、重量が
最小のもので３８７ｍｍ、重量が最大のもので３８１ｍ
ｍあり、平均長は３８３ｍｍとなった。以上の測定値に
よれば、各射出成形における溶融樹脂の充填量には、−
０．５〜＋０．３ｇの範囲で「充填むら」があり、この
「充填むら」によりガスチャンネル24の長さが−２〜＋
４ｍｍの範囲で変動したことがわかる。ここで、全テス
トピース30について目視で検査を行ったところ、各表面
にヒケ等の不良箇所が全くないから、「充填むら」によ
る充填量の変動分は、長さ寸法が４０ｍｍの緩衝部25に
より充分吸収できたことがわかる。[Experimental Result] In the experimental example, all the obtained test pieces 30 were provided with a buffer section 25 as shown in FIG.
A gas channel 24 was formed to reach the inside of the. As a result of measuring the weight of each of the test pieces 30, the lightest one is 114.1 g and the heaviest one is 11.
It weighed 4.9 g, and its average weight was 114.6 g.
On the other hand, as a result of measuring the total length of the gas channel 24, the smallest one has a weight of 387 mm, and the largest one has a weight of 381 m.
m, and the average length was 383 mm. According to the above measured values, the filling amount of the molten resin in each injection molding is −
There is "filling unevenness" in the range of 0.5 to +0.3 g, and the length of the gas channel 24 is -2 to + due to this "filling unevenness".
It can be seen that it fluctuated within the range of 4 mm. Here, when all the test pieces 30 are visually inspected, there is no defective portion such as a sink mark on each surface. Therefore, the variation of the filling amount due to the "filling unevenness" is caused by the buffer portion 25 having a length of 40 mm. It can be seen that the absorption was sufficient.
【００１６】比較例では、前記実験例と同様に、全ての
テストピース40の各々について、重量およびガスチャン
ネル24の全長を測定した結果、最も軽いものが１１３．
４ｇ、最も重いものが１１４．６ｇあり、その平均重量
は１１４．３ｇとなった。一方、ガスチャンネル24の全
長は、最小重量のもので３７７．８ｍｍ、最大重量のも
ので３７４．６ｍｍあり、平均長は３７６．１ｍｍとな
った。以上の測定値によれば、各射出成形における溶融
樹脂の充填量には、−０．９〜＋０．３ｇの範囲で「充
填むら」があり、この「充填むら」によりガスチャンネ
ル24の長さが−１．５〜＋１．７ｍｍの範囲内で変動し
ているのがわかる。ここで、全テストピース40について
目視で検査を行ったところ、重量の重いものには、表面
にヒケ等の不良箇所が発生していた。最大重量のものに
ついて内部検査を行ったところ、中空厚肉部23の末端部
分31の内部にはガスチャンネル24が到達できす、当該末
端部分31は、内部に樹脂が詰まったソリッド状になって
いた。この末端部分31は長さ寸法Ｌ３が５．４ｍｍあ
り、その表面に深さが１５μｍのヒケ32が生じていた。In the comparative example, the weight and the total length of the gas channel 24 were measured for each of all the test pieces 40, and the lightest one was 113.
4 g, the heaviest one was 114.6 g, and the average weight was 114.3 g. On the other hand, the total length of the gas channel 24 was 377.8 mm for the minimum weight and 374.6 mm for the maximum weight, and the average length was 376.1 mm. According to the above measured values, the filling amount of the molten resin in each injection molding has "uneven filling" in the range of -0.9 to +0.3 g, and the length of the gas channel 24 is due to this "uneven filling". It can be seen that fluctuates within the range of -1.5 to +1.7 mm. Here, when all the test pieces 40 were visually inspected, defective parts such as sink marks were found on the surface of the heavy test piece. When an internal inspection was performed on the largest weight, the gas channel 24 was able to reach the inside of the end portion 31 of the hollow thick portion 23. The end portion 31 had a solid state in which resin was clogged. It was The end portion 31 had a length dimension L3 of 5.4 mm, and a sink mark 32 having a depth of 15 μm was formed on the surface thereof.
【００１７】なお、本発明は前述の各実施例に限定され
るものではなく、次に示すような変形などをも含むもの
である。すなわち、バッファ形成部および緩衝部として
は、高さ寸法Ｈを漸次減少したものに限らず、図６に示
されるように、幅寸法Ｗ２を漸次減少したものや、図７
に示されるように、高さ寸法Ｈおよび幅寸法Ｗ２の両方
を漸次減少したものでもよい。The present invention is not limited to the above-described embodiments, but includes the following modifications and the like. That is, the buffer forming portion and the buffer portion are not limited to those in which the height dimension H is gradually reduced, but those in which the width dimension W2 is gradually reduced as shown in FIG.
As shown in, both the height dimension H and the width dimension W2 may be gradually reduced.
【００１８】また、バッファ形成部および緩衝部の形状
は、直線のみで構成されたものに限らず、図８に示され
るように、曲線で構成されるバッファ形成部15A および
緩衝部25A や、図９に示されるように、階段状に断面積
が漸次減少するバッファ形成部15B および緩衝部25B で
もよい。Further, the shapes of the buffer forming portion and the buffer portion are not limited to those formed by only straight lines, and as shown in FIG. 8, the buffer forming portion 15A and the buffer portion 25A formed by curved lines, As shown in FIG. 9, the buffer forming portion 15B and the buffer portion 25B may have a stepwise decreasing cross-sectional area.
【００１９】また、ガスチャンネル案内部および厚肉形
成部としては、一本の直線から形成されるものに限ら
ず、平面Ｈ字状に形成されたもの等でもよく、その平面
形状は実施にあたり適宜選択すればよい。Further, the gas channel guide portion and the thick wall forming portion are not limited to those formed by a single straight line, but may be those formed in a plane H shape, etc. Just select it.
【００２０】さらに、ガス射出成形品としては、平板状
のものに限らず、箱状のものでもよく、要するに、本発
明は、一個以上の平面もしくは曲面、または、平面およ
び曲面を相互に合わせた面等から構成される成形品の成
形に適用できる。Further, the gas injection molded product is not limited to a flat plate-shaped product, but may be a box-shaped product. In short, according to the present invention, one or more flat surfaces or curved surfaces, or flat surfaces and curved surfaces are combined with each other. It can be applied to the molding of molded products composed of surfaces and the like.
【００２１】[0021]
【発明の効果】前述のように本発明によれば、ガス射出
成形に係る制御を容易にでき、かつヒケや孔等の不良箇
所の発生を未然に防止することができる。As described above, according to the present invention, it is possible to easily control the gas injection molding and prevent the occurrence of defective portions such as sink marks and holes.
【図１】本発明の一実施例の金型を示す斜視図である。FIG. 1 is a perspective view showing a mold according to an embodiment of the present invention.
【図２】本発明の実験例における成形品を示す三面図で
ある。FIG. 2 is a three-view drawing showing a molded product in an experimental example of the present invention.
【図３】比較例における成形品を示す三面図である。FIG. 3 is a trihedral view showing a molded product in a comparative example.
【図４】前記実験例の結果を示す拡大された要部断面図
である。FIG. 4 is an enlarged cross-sectional view of an essential part showing a result of the experimental example.
【図５】前記比較例の結果を示す拡大された要部断面図
である。FIG. 5 is an enlarged cross-sectional view of an essential part showing a result of the comparative example.
【図６】本発明の変形例を示す斜視図である。FIG. 6 is a perspective view showing a modified example of the present invention.
【図７】本発明の別の変形例を示す斜視図である。FIG. 7 is a perspective view showing another modification of the present invention.
【図８】本発明の異なる変形例を示す斜視図である。FIG. 8 is a perspective view showing another modification of the present invention.
【図９】本発明のさらに異なる変形例を示す斜視図であ
る。FIG. 9 is a perspective view showing still another modified example of the present invention.
10 金型 11 キャビティ 13 ガスチャンネル案内部 15 バッファ形成部 20 成形品 23 中空厚肉部 24 ガスチャンネル 30 成形品としてのテストピース 10 Mold 11 Cavity 13 Gas channel guide part 15 Buffer forming part 20 Molded product 23 Hollow thick part 24 Gas channel 30 Test piece as molded product
Claims (2)
ネルを囲む中空厚肉部の末端部分が先細りとなっている
ことを特徴とするガス射出成形品。1. A gas injection molded article, characterized in that a hollow thick portion surrounding a gas channel formed by injecting gas inside has a tapered end portion.
くしたガスチャンネル案内部と、このガスチャンネル案
内部の末端部分を先細りにして形成したバッファ形成部
とを備えた金型に溶融樹脂の充填を開始した後、充填さ
れた溶融樹脂内にガスを注入することを特徴とするガス
射出成形方法。2. A mold provided with a gas channel guide portion in which the thickness of the cavity is made thicker than the surroundings in advance, and a buffer forming portion formed by tapering the end portion of the gas channel guide portion. A gas injection molding method, comprising injecting a gas into the filled molten resin after starting the filling.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9935093A JP3238791B2 (en) | 1993-04-26 | 1993-04-26 | Gas injection molded article and molding method thereof |
| CA002121521A CA2121521A1 (en) | 1993-04-26 | 1994-04-18 | Gas-introduced injection molding and method of obtaining the same |
| US08/232,773 US5514447A (en) | 1993-04-26 | 1994-04-25 | Gas-introduced injection molding and method of obtaining the same |
| US08/539,598 US5750068A (en) | 1993-04-26 | 1995-10-05 | Gas-introduced injection molding and method of obtaining the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9935093A JP3238791B2 (en) | 1993-04-26 | 1993-04-26 | Gas injection molded article and molding method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06304954A true JPH06304954A (en) | 1994-11-01 |
| JP3238791B2 JP3238791B2 (en) | 2001-12-17 |
Family
ID=14245169
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9935093A Expired - Lifetime JP3238791B2 (en) | 1993-04-26 | 1993-04-26 | Gas injection molded article and molding method thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3238791B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114701120A (en) * | 2022-04-02 | 2022-07-05 | 台州市陆讯塑业股份有限公司 | Buffering guide device for injection molding machine |
-
1993
- 1993-04-26 JP JP9935093A patent/JP3238791B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114701120A (en) * | 2022-04-02 | 2022-07-05 | 台州市陆讯塑业股份有限公司 | Buffering guide device for injection molding machine |
| CN114701120B (en) * | 2022-04-02 | 2023-09-22 | 台州市陆讯塑业股份有限公司 | Buffering guide device for injection molding machine |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3238791B2 (en) | 2001-12-17 |
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