JPH1015981A - Manufacture of hollow molded body - Google Patents
Manufacture of hollow molded bodyInfo
- Publication number
- JPH1015981A JPH1015981A JP8186694A JP18669496A JPH1015981A JP H1015981 A JPH1015981 A JP H1015981A JP 8186694 A JP8186694 A JP 8186694A JP 18669496 A JP18669496 A JP 18669496A JP H1015981 A JPH1015981 A JP H1015981A
- Authority
- JP
- Japan
- Prior art keywords
- gas
- hollow
- molten resin
- resin
- gates
- 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.)
- Pending
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
-
- 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
- B29C2045/173—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 using a plurality of fluid injection nozzles
Abstract
Description
【０００１】[0001]
【技術分野】本発明は，外観，強度のばらつきの少ない
中空成形体の製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hollow molded article having little variation in appearance and strength.
【０００２】[0002]
【従来技術】従来より，樹脂成形体においては，軽量化
及び省資源化等を目標として，内部に中空部を有する中
空成形体が種々製造されている。この中空成形体を製造
する方法としては，成形型のキャビティ内に溶融樹脂を
射出し，次いで，溶融樹脂内に中空部形成用のガスを注
入する方法が用いられている。2. Description of the Related Art Conventionally, various hollow molded articles having a hollow portion therein have been manufactured for the purpose of weight reduction and resource saving of resin molded articles. As a method of manufacturing the hollow molded body, a method of injecting a molten resin into a cavity of a molding die and then injecting a gas for forming a hollow portion into the molten resin is used.
【０００３】また，上記中空成形体のうち，例えば長尺
の成形体を製造する場合には，キャビティ内に溶融樹脂
を射出するための樹脂ゲートと，中空部形成用ガスを注
入するためのガスゲートを，それぞれ複数備えた成形
型，いわゆる多点ゲートタイプの成形型を用いる場合が
ある。例えば，図６（ａ）〜（ｃ）に示すごとく，キャ
ビティ２の左右にそれぞれ樹脂ゲート３とガスゲート４
とを有する成形型１を用いる場合がある。[0003] In the case of manufacturing a long molded product among the above-mentioned hollow molded products, for example, a resin gate for injecting a molten resin into a cavity and a gas gate for injecting a gas for forming a hollow portion are provided. , A so-called multi-point gate type mold may be used. For example, as shown in FIGS. 6A to 6C, a resin gate 3 and a gas gate 4 are provided on the left and right sides of the cavity 2, respectively.
May be used.
【０００４】この場合には，まず，図６（ａ）に示すご
とく，上記２箇所の樹脂ゲート３からキャビティ２内に
それぞれ溶融樹脂７を射出する（矢印Ｒ）。その後，図
６（ｂ）に示すごとく，上記溶融樹脂７の中にそれぞれ
ガス注入（矢印Ｇ）を行う。これにより，左右の溶融樹
脂７が中央部に向かって前進しつつ，溶融樹脂７中に中
空部７１，７２が形成されていく。In this case, first, as shown in FIG. 6A, molten resin 7 is injected into the cavity 2 from the two resin gates 3 (arrow R). Thereafter, as shown in FIG. 6B, gas injection (arrow G) is performed into the molten resin 7 respectively. Thereby, the hollow portions 71 and 72 are formed in the molten resin 7 while the left and right molten resins 7 advance toward the center.
【０００５】そして，図６（ｃ）に示すごとく，両側か
ら進んできた溶融樹脂７が当接して一体化することによ
り成形品を形成すると共にその略中央部分にウエルド部
６を形成する。このとき，上記樹脂７中の中空部７１，
７２を形成しているガスも，圧力的に平衡状態となって
その進行が止まる。これにより，上記ウエルド部６を有
する長尺の中空成形体９が得られる。Then, as shown in FIG. 6C, the molten resin 7 which has advanced from both sides abuts and integrates to form a molded product, and a weld portion 6 is formed substantially at the center thereof. At this time, the hollow portion 71 in the resin 7
The gas forming 72 also becomes equilibrium in pressure and stops its progress. As a result, a long hollow molded body 9 having the above weld portion 6 is obtained.
【０００６】[0006]
【解決しようとする課題】しかしながら，上記従来の中
空成形体９の製造方法においては，次の問題がある。即
ち，上記多点ゲートタイプの成形型によって製造した中
空成形体は，上記のごとく，溶融樹脂７が当接した部分
にウエルド部６を形成している。However, the conventional method of manufacturing the hollow molded article 9 has the following problems. That is, as described above, the hollow molded body manufactured by the multipoint gate type molding die has the welded portion 6 formed at the portion where the molten resin 7 contacts.
【０００７】このウエルド部６は，中実であって，中空
部７１，７２を有する部分に比べて厚肉である。そのた
め，溶融樹脂７の冷却過程において，ウエルド部６の外
表面にヒケが生じたり，逆に盛り上がりが生じたりする
場合がある。即ち，ウエルド部６を有する成形品は，外
観不良が発生しやすい。The weld portion 6 is solid and thicker than the portion having the hollow portions 71 and 72. Therefore, in the process of cooling the molten resin 7, sinks may occur on the outer surface of the welded portion 6, or conversely, swelling may occur. That is, a molded article having the weld portion 6 is liable to have poor appearance.
【０００８】また，上記中空成形体９における樹脂の配
向は，全体的には溶融樹脂７の流れ方向に沿って形成さ
れる。しかしながら，図７に示すごとく，上記ウエルド
部６における樹脂の配向Ｓは，溶融樹脂７の流れる方向
と直角な方向に，溶融樹脂７の当接面に沿って形成され
る。そのため，外部から受ける曲げ応力等に対する強度
は，上記配向の違いによって，ウエルド部６の方が中空
部７１，７２を有する部分よりも弱くなる傾向がある。The orientation of the resin in the hollow molded body 9 is generally formed along the flow direction of the molten resin 7. However, as shown in FIG. 7, the orientation S of the resin in the weld portion 6 is formed along the contact surface of the molten resin 7 in a direction perpendicular to the direction in which the molten resin 7 flows. Therefore, the strength against the bending stress or the like received from the outside tends to be weaker in the weld portion 6 than in the portion having the hollow portions 71 and 72 due to the difference in the orientation.
【０００９】特に，グラスファイバー，炭素ファイバー
等の繊維状フィラーを含有させて樹脂の強化を図ってい
る場合には，繊維状フィラーの配向も，上記樹脂の配向
に伴って，上記ウエルド部の当接面に沿って形成され，
その強化作用を半減させてしまう。そのため，得られた
中空成形体は，そのウエルド部の強度が局部的に低くな
り，強度部品としての価値が低下してしまう。In particular, when the resin is reinforced by including a fibrous filler such as glass fiber or carbon fiber, the orientation of the fibrous filler also changes with the orientation of the resin in accordance with the orientation of the resin. Formed along the interface,
The strengthening action is halved. Therefore, the strength of the welded portion of the obtained hollow molded body is locally reduced, and the value as a strength component is reduced.
【００１０】これに対し，上記成形型の多点ゲートを１
つに減らした場合には上記ウエルド部６の形成を無くす
ることができる。しかしながら，この場合には，一つの
ゲートからキャビティ全体に溶融樹脂を供給する必要が
あるため，長尺の場合等には溶融樹脂の流れ性が悪化
し，成形性自体に問題が発生する場合がある。そのた
め，単純に上記ゲート数を減少させることはできない。On the other hand, the multipoint gate of the above-mentioned mold is connected to one gate.
When the number is reduced to one, the formation of the weld portion 6 can be eliminated. However, in this case, since it is necessary to supply the molten resin from one gate to the entire cavity, the flowability of the molten resin is deteriorated when the length is long, and a problem may occur in the moldability itself. is there. Therefore, the number of gates cannot be simply reduced.
【００１１】本発明は，かかる従来の問題点に鑑みてな
されたもので，多点ゲートタイプの成形型を用いても，
外観に優れ，強度ムラのない中空成形体が得られる，中
空成形体の製造方法を提供しようとするものである。The present invention has been made in view of such a conventional problem, and even when a multipoint gate type molding die is used,
An object of the present invention is to provide a method for producing a hollow molded article which is excellent in appearance and can obtain a hollow molded article having no strength unevenness.
【００１２】[0012]
【課題の解決手段】請求項１の発明は，キャビティ内に
複数の樹脂ゲートより溶融樹脂を射出し，次いで，上記
溶融樹脂中に複数のガスゲートよりガスを圧入して複数
の中空部を形成すると共にこれら中空部の間には溶融樹
脂の流れが当接することによって形成されたウエルド部
を形成し，次いで，上記複数のガスゲートのうち少なく
とも一つのガスゲートにおけるガス圧力を他のガスゲー
トの圧力よりも低下させて，上記ウエルド部を破壊して
貫通中空部を形成することを特徴とする中空成形体の製
造方法にある。According to a first aspect of the present invention, a plurality of resin gates are used to inject molten resin into a cavity, and then a plurality of hollow portions are formed by injecting gas into the molten resin from a plurality of gas gates. At the same time, a weld is formed between the hollows due to the contact of the flow of the molten resin, and then the gas pressure in at least one of the plurality of gas gates is reduced below the pressure of the other gas gates. Then, the weld portion is broken to form a through hollow portion, and the method for manufacturing a hollow molded body is provided.
【００１３】本発明において最も注目すべきことは，上
記ウエルド部形成後，上記複数のガスゲートのうち少な
くとも一つのガスゲートにおけるガス圧力を他のガスゲ
ートの圧力よりも低下させることである。What is most notable in the present invention is that, after the formation of the weld portion, the gas pressure in at least one of the plurality of gas gates is made lower than the pressure in the other gas gates.
【００１４】上記方法を実施するための成形型において
は，上記のごとく，樹脂ゲートとガスゲートとをそれぞ
れ複数箇所に設ける。この場合，樹脂ゲートとガスゲー
トとは，キャビティの形状等に応じて兼用させることも
できるし，別個独立に設けることもできる。In the molding die for carrying out the above method, as described above, a resin gate and a gas gate are provided at a plurality of locations. In this case, the resin gate and the gas gate can be used in accordance with the shape of the cavity or the like, or can be provided separately and independently.
【００１５】次に，本発明の作用につき説明する。本発
明の中空成形体の製造方法においては，上記のごとく，
上記ウエルド部形成後に，複数のガスゲートのうち少な
くとも一つのガスゲートの圧力を他のガスゲートの圧力
よりも低下させる。これにより，低圧にしたガスゲート
に対応する中空部の内部圧力は低圧状態となる。Next, the operation of the present invention will be described. In the method for producing a hollow molded body of the present invention, as described above,
After the formation of the weld portion, the pressure of at least one of the plurality of gas gates is made lower than the pressure of the other gas gates. As a result, the internal pressure of the hollow portion corresponding to the low-pressure gas gate becomes low.
【００１６】そのため，低圧状態の中空部と高圧状態に
ある他の中空部との間に形成されたウエルド部は，その
圧力差によって低圧側の中空部内の方向に押圧されて破
壊される。これにより，中空部は高圧側から低圧側まで
貫通した状態となり，成形後におけるウエルド部の残存
を阻止することができる。Therefore, the weld formed between the hollow portion in the low pressure state and the other hollow portion in the high pressure state is pressed by the pressure difference in the hollow portion on the low pressure side and is broken. As a result, the hollow portion penetrates from the high pressure side to the low pressure side, and it is possible to prevent the weld portion from remaining after molding.
【００１７】そのため，成形途中においてウエルド部で
あった部分においても，その内部が中空状となり，薄肉
状となる。それ故，ヒケや盛り上がり等の外観不良が発
生することがない。[0017] Therefore, even in the part which was a weld part during molding, the inside becomes hollow and thin. Therefore, appearance defects such as sink marks and swelling do not occur.
【００１８】また，ウエルド部にあった余剰樹脂は，上
記ウエルド部の破壊によって，低圧側の中空部の内面に
覆い被さるように配置される（図４参照）。そして，そ
の覆い被さった余剰樹脂部分の配向は，元々中空部であ
る部分と同じ方向，即ち樹脂流れ方向と同様になる。そ
のため，従来のようにウエルド部のみが配向の違いによ
って強度低下するということがない。それ故，本発明に
よって得られた中空成形体は，多点ゲートタイプの成形
型を用いて成形しても，外観に優れ，かつ強度ムラのな
いものとすることができる。The surplus resin existing in the weld portion is disposed so as to cover the inner surface of the low pressure side hollow portion due to the destruction of the weld portion (see FIG. 4). The orientation of the surplus resin portion covered is the same as that of the originally hollow portion, that is, the resin flow direction. Therefore, unlike the conventional case, the strength of only the weld portion does not decrease due to the difference in orientation. Therefore, the hollow molded article obtained by the present invention can have excellent appearance and no strength unevenness even when molded using a multipoint gate type mold.
【００１９】次に，請求項２の発明のように，上記溶融
樹脂中には，繊維状フィラーを含有させることができ
る。この繊維状フィラーとしては，例えば炭素ファイバ
ー，グラスファイバー，金属繊維，無機針状フィラー等
がある。これにより，中空成形体全体を強化することが
でき，また従来のようにウエルド部に局部的に強度の弱
い部分が発生するということがない。Next, as in the second aspect of the present invention, the molten resin may contain a fibrous filler. Examples of the fibrous filler include carbon fiber, glass fiber, metal fiber, and inorganic needle-like filler. As a result, the entire hollow molded body can be strengthened, and a locally weak portion does not occur in the weld portion unlike the conventional case.
【００２０】即ち，上記のごとく溶融樹脂の配向は，ウ
エルド部であった部分においても溶融樹脂の流れ方向と
同じ方向となり，これに伴って繊維状フィラーの配向も
同じ方向となる。そのため，ウエルド部であった部分だ
けが強度低下するということがなく，繊維状フィラー添
加の効果を最大限に発揮させることができる。That is, as described above, the orientation of the molten resin also becomes the same direction as the flow direction of the molten resin even in the weld portion, and accordingly, the orientation of the fibrous filler also becomes the same direction. Therefore, the strength of only the weld portion is not reduced, and the effect of the addition of the fibrous filler can be maximized.
【００２１】また，この場合の溶融樹脂中への繊維状フ
ィラーの含有量は，１５〜６０重量％であることが好ま
しい。１５重量％未満の場合には，その添加による強化
効果が十分に得られないという問題があり，一方６０重
量％を越える場合には，樹脂の靱性が低下するという問
題がある。In this case, the content of the fibrous filler in the molten resin is preferably 15 to 60% by weight. If the amount is less than 15% by weight, there is a problem that the reinforcing effect by the addition cannot be sufficiently obtained, while if it exceeds 60% by weight, there is a problem that the toughness of the resin is reduced.
【発明の実施の形態】 実施形態例１ 本発明の実施形態例にかかる中空成形体の製造方法につ
き，図１〜図４を用いて説明する。本例において製造す
る中空成形体は，図２，図３に示すごとく，自動車のル
ーフ上に設ける樹脂製ルーフレール８である。また，製
造に使用する成形型１は，図１（ａ）〜（ｄ）に示すご
とく，キャビティ２の両端側にそれぞれ樹脂ゲート３及
びガスゲート４を設けてなる多点ゲートタイプの成形型
である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment A method for manufacturing a hollow molded body according to an embodiment of the present invention will be described with reference to FIGS. The hollow molded body manufactured in this example is a resin roof rail 8 provided on the roof of an automobile as shown in FIGS. As shown in FIGS. 1 (a) to 1 (d), a molding die 1 used for manufacturing is a multi-point gate type molding die in which a resin gate 3 and a gas gate 4 are provided at both ends of a cavity 2, respectively. .
【００２２】そして，上記成形型１を用いてルーフレー
ル８を製造するに当たっては，まず図１（ａ）に示すご
とく，キャビティ２内に両側２つの樹脂ゲート３より，
ルーフレール８を成形するのに必要な量の溶融樹脂７を
射出する（矢印Ｒ）。次いで，図１（ｂ）（ｃ）に示す
ごとく，溶融樹脂７中に両側２つのガスゲート４より窒
素（Ｎ2 ）ガスを圧入する（矢印Ｇ）。これにより，左
右に２つの中空部７１，７２を形成すると共にこれら中
空部７１，７２の間には溶融樹脂７の流れが当接するこ
とによって形成されたウエルド部６を形成する。In manufacturing the roof rail 8 using the molding die 1, first, as shown in FIG.
The required amount of molten resin 7 for molding the roof rail 8 is injected (arrow R). Next, as shown in FIGS. 1B and 1C, nitrogen (N 2 ) gas is injected into the molten resin 7 from two gas gates 4 on both sides (arrow G). As a result, two hollow portions 71 and 72 are formed on the left and right, and a weld portion 6 formed by contact of the flow of the molten resin 7 is formed between the hollow portions 71 and 72.
【００２３】この状態で成形を終了させた場合には，従
来と同様にウエルド部６が残存する。そのため，次のよ
うな手順でウエルド部６を無くする。即ち，図１（ｄ）
中における左側のガスゲート３の圧力を低下させる。こ
れにより，左側の中空部７１の内部圧力は低下し，一
方，右側の中空部７２は高圧のままであるため，両者の
圧力差が大きくなる。When the molding is completed in this state, the weld portion 6 remains as in the conventional case. Therefore, the weld portion 6 is eliminated by the following procedure. That is, FIG.
The pressure of the left gas gate 3 in the inside is reduced. As a result, the internal pressure of the left hollow portion 71 decreases, while the right hollow portion 72 remains at a high pressure, so that the pressure difference between the two increases.
【００２４】そのため，図１（ｄ）に示すごとく，窒素
ガスは矢印Ｌの方向に流れ，ウエルド部６は低圧側に向
かって破壊される。それ故，ウエルド部６に存在してい
た余剰樹脂６５は低圧側の中空部７１の内面に覆い被さ
る。これにより，図３に示すごとく，貫通した一つの貫
通中空部７０を有するルーフレール８が得られる。尚，
符号８６は，ルーフレール取付用のスタッドボルトであ
って，成形型１に予めセットしておいたもの（図示略）
である。Therefore, as shown in FIG. 1D, the nitrogen gas flows in the direction of arrow L, and the weld portion 6 is broken down toward the low pressure side. Therefore, the surplus resin 65 existing in the welded portion 6 covers the inner surface of the hollow portion 71 on the low pressure side. Thereby, as shown in FIG. 3, the roof rail 8 having one penetrating hollow portion 70 is obtained. still,
Reference numeral 86 denotes a stud bolt for mounting the roof rail, which is set in the molding die 1 in advance (not shown).
It is.
【００２５】また，本例における溶融樹脂７としては，
グラスファイバー入りポリアミド（ＰＡ（ＧＦ））を用
いている。尚，グラスファイバーの含有率は，５５重量
％に調整してある。このグラスファイバーは，溶融樹脂
７の流れに伴って成形品全体に分散し，その強度の向上
に寄与する。Further, the molten resin 7 in the present example includes:
Polyamide containing glass fiber (PA (GF)) is used. The glass fiber content was adjusted to 55% by weight. The glass fibers are dispersed throughout the molded article with the flow of the molten resin 7 and contribute to the improvement of the strength.
【００２６】そして，図４に示すごとく，ウエルド部６
が存在していた部分の余剰樹脂６５の部分におけるグラ
スファイバー７５の配向は，その前後の部分と同様に，
溶融樹脂７の流れの方向に向いた状態に形成される。即
ち，ルーフレール８におけるグラスファイバー７５の配
向は，ほぼ均一にその長手方向に向かって形成される。Then, as shown in FIG.
The orientation of the glass fiber 75 in the portion of the surplus resin 65 in the portion where
It is formed in a state facing the flow direction of the molten resin 7. That is, the orientation of the glass fiber 75 on the roof rail 8 is formed substantially uniformly in the longitudinal direction.
【００２７】このように，本例において得られたルーフ
レール８は，多点ゲートタイプの成形型により成形した
にもかかわらず，ウエルド部を有せず，かつ，樹脂及び
グラスファイバーの配向は，全体的に長手方向にほぼ均
一に形成されている。そのため，従来のようなウエルド
部の存在に起因する外観不良や，強度ムラの発生を確実
に防止することができる。As described above, the roof rail 8 obtained in this embodiment has no weld portion and the orientation of the resin and the glass fiber is entirely despite the fact that the roof rail 8 is formed by the multipoint gate type forming die. It is formed substantially uniformly in the longitudinal direction. Therefore, it is possible to reliably prevent the appearance defect and the strength unevenness caused by the presence of the weld portion as in the related art.
【００２８】尚，本例においては，上記溶融樹脂７とし
てＰＡ（ＧＦ）を用いたが，これに代えて，グラスファ
イバー入りのポリカーボネート／ポリブチレンテレフタ
レート（ＰＣ／ＰＢＴ（ＧＦ）），グラスファイバー入
りのポリカーボネート／ポリエチレンテレフタレート
（ＰＣ／ＰＥＴ（ＧＦ））等を用いることもできる。In this example, PA (GF) was used as the molten resin 7, but instead of polycarbonate / polybutylene terephthalate (PC / PBT (GF)) containing glass fiber, or glass fiber. Polycarbonate / polyethylene terephthalate (PC / PET (GF)) or the like can also be used.
【００２９】実施形態例２ 本例においては，図５（ａ）に示すごとく，成形途中に
おいて，２箇所にウエルド部が形成される場合について
説明する。即ち，図５（ａ）に示すごとく，３箇所にそ
れぞれ設けた樹脂ゲート及びガスゲート（図示略）から
それぞれ溶融樹脂７を注入すると共にガスを圧入（矢印
Ｇ）した場合には，３つの中空部７０１，７０２，７０
３がそれぞれ形成され，これらの当接部２箇所において
ウエルド部６０１，６０２が形成される。Embodiment 2 In this embodiment, as shown in FIG. 5A, a case where two weld portions are formed during molding will be described. That is, as shown in FIG. 5 (a), when molten resin 7 is injected from resin gates and gas gates (not shown) provided at three places and gas is injected (arrow G), three hollow portions are formed. 701, 702, 70
3 are formed, and weld portions 601 and 602 are formed at these two contact portions.
【００３０】この場合には，図５（ｂ）に示すごとく，
その中央部の中空部７０２に対応するガスゲート（図示
略）の圧力を低下させ，一方，その他のガスゲートの圧
力は高いまま維持する。これにより，中空部間には圧力
差が発生する。そのため，ガスは矢印Ｌの方向に流れ，
２箇所のウエルド部６０１，６０２は，それぞれ中空部
７０２側に向かって破壊され，１本の貫通した中空部７
００となる。In this case, as shown in FIG.
The pressure of the gas gate (not shown) corresponding to the central hollow portion 702 is reduced, while the pressure of the other gas gates is kept high. As a result, a pressure difference is generated between the hollow portions. Therefore, the gas flows in the direction of arrow L,
Each of the two weld portions 601 and 602 is broken toward the hollow portion 702, and one welded hollow portion 7 is formed.
00.
【００３１】そして，図５（ｂ）に示すごとく，上記ウ
エルド部６０１，６０２であった部分の余剰樹脂６０５
は，それぞれ中央側の中空部内面に覆い被さる。それ
故，この場合にも，実施形態例１と同様に，ウエルド部
が存在することによる不具合の発生を確実に阻止するこ
とができる。Then, as shown in FIG. 5B, the surplus resin 605 in the portions which were the weld portions 601 and 602 are used.
Respectively cover the inner surface of the hollow part on the center side. Therefore, also in this case, similarly to the first embodiment, it is possible to reliably prevent the occurrence of a problem due to the presence of the weld portion.
【００３２】尚，ウエルド部がさらに多く形成される場
合においても，そのウエルド部の両側に位置する中空部
内の一方の圧力を低下させるように，特定のガスゲート
の圧力を低下させることにより，上記と同様にウエルド
部の破壊を行うことができる。Incidentally, even in the case where more welds are formed, the pressure of a specific gas gate is reduced so as to reduce the pressure of one of the hollows located on both sides of the welds. Similarly, the weld portion can be destroyed.
【００３３】[0033]
【発明の効果】上記のごとく，本発明によれば，多点ゲ
ートを有する成形型を用いても，外観に優れ，強度ムラ
のない中空成形体が得られる，中空成形体の製造方法を
提供することができる。As described above, according to the present invention, there is provided a method of manufacturing a hollow molded article which is excellent in appearance and has no strength unevenness even when a molding die having a multipoint gate is used. can do.
【図１】実施形態例１における，（ａ）溶融樹脂を射出
している状態，（ｂ）溶融樹脂中にガスを注入している
状態，（ｃ）ウエルド部が形成された状態，（ｄ）ウエ
ルド部が破壊された状態，を示す説明図。FIG. 1 shows a state (a) in which molten resin is injected, (b) a state in which gas is injected into molten resin, (c) a state in which a weld portion is formed, and (d) in the first embodiment. FIG. 4 is an explanatory view showing a state in which a weld portion is broken.
【図２】実施形態例１における，ルーフレールの斜視
図。FIG. 2 is a perspective view of a roof rail according to the first embodiment.
【図３】実施形態例１における，ルーフレールの要部断
面図。FIG. 3 is a sectional view of a main part of a roof rail according to the first embodiment.
【図４】実施形態例１における，ウエルド部にあった余
剰樹脂部分のグラスファイバーの配向状態を示す説明
図。FIG. 4 is an explanatory diagram showing an orientation state of glass fibers in a surplus resin portion existing in a weld portion in the first embodiment.
【図５】実施形態例２における，（ａ）２箇所のウエル
ド部が形成された状態，（ｂ）ウエルド部が破壊された
状態，を示す説明図。5A and 5B are explanatory views showing (a) a state in which two welds are formed and (b) a state in which the welds are broken in the second embodiment.
【図６】従来例における，（ａ）溶融樹脂を射出してい
る状態，（ｂ）溶融樹脂中にガスを注入している状態，
（ｃ）ウエルド部が形成された状態，を示す説明図。6 (a) shows a state in which molten resin is injected, FIG. 6 (b) shows a state in which gas is injected into molten resin, and FIG.
(C) Explanatory drawing which shows the state in which the weld part was formed.
【図７】従来例における，ウエルド部の樹脂の配向状態
を示す説明図。FIG. 7 is an explanatory view showing an orientation state of a resin in a weld portion in a conventional example.
１．．．成形型， ２．．．キャビティ， ３．．．樹脂ゲート， ４．．．ガスゲート， ６，６０１，６０２．．．ウエルド部， ７．．．溶融樹脂， ７０，７１，７２，７０１，７０２，７０３．．．中空
部， ８．．．ルーフレール，1. . . Mold, 2. . . Cavity, 3. . . 3. resin gate; . . Gas gate, 6,601,602. . . 6. Weld part, . . Molten resin, 70, 71, 72, 701, 702, 703. . . Hollow, 8. . . Roof rail,
Claims (2)
融樹脂を射出し，次いで，上記溶融樹脂中に複数のガス
ゲートよりガスを圧入して複数の中空部を形成すると共
にこれら中空部の間には溶融樹脂の流れが当接すること
によって形成されたウエルド部を形成し，次いで，上記
複数のガスゲートのうち少なくとも一つのガスゲートに
おけるガス圧力を他のガスゲートの圧力よりも低下させ
て，上記ウエルド部を破壊して貫通中空部を形成するこ
とを特徴とする中空成形体の製造方法。1. A molten resin is injected into a cavity from a plurality of resin gates, and then a gas is injected into the molten resin from a plurality of gas gates to form a plurality of hollow portions and a gap between the hollow portions. Forming a weld formed by the contact of the flow of the molten resin, and then reducing the gas pressure in at least one of the plurality of gas gates below the pressure of the other gas gates to destroy the weld; Forming a hollow through-hole by forming the hollow molded body.
は，繊維状フィラーを含有していることを特徴とする中
空成形体の製造方法。2. The method according to claim 1, wherein the molten resin contains a fibrous filler.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8186694A JPH1015981A (en) | 1996-06-26 | 1996-06-26 | Manufacture of hollow molded body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8186694A JPH1015981A (en) | 1996-06-26 | 1996-06-26 | Manufacture of hollow molded body |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH1015981A true JPH1015981A (en) | 1998-01-20 |
Family
ID=16193005
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8186694A Pending JPH1015981A (en) | 1996-06-26 | 1996-06-26 | Manufacture of hollow molded body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH1015981A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001062479A1 (en) | 2000-02-24 | 2001-08-30 | Conix Corporation | Injection molding techniques utilizing fluid channels |
| US6843954B2 (en) | 2000-02-24 | 2005-01-18 | Conix Corporation | Injection molding techniques utilizing fluid channels |
| WO2005018902A1 (en) * | 2003-08-22 | 2005-03-03 | Suzuka Fuji Xerox Co., Ltd. | Hollow molded product, method of manufacturing hollow molded product, and metal mold for hollow molding |
| US6872355B2 (en) | 1998-06-11 | 2005-03-29 | Asahi Kasei Kogyo Kabushiki Kaisha | Roof rail and method for producing the roof rail |
| US6998174B2 (en) | 2000-02-24 | 2006-02-14 | Conix Corporation | Integrated co-injection molded vehicle components and methods of making the same |
| EP2623290A1 (en) * | 2010-09-30 | 2013-08-07 | Asahi Kasei Chemicals Corporation | Injection-molded object |
-
1996
- 1996-06-26 JP JP8186694A patent/JPH1015981A/en active Pending
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6872355B2 (en) | 1998-06-11 | 2005-03-29 | Asahi Kasei Kogyo Kabushiki Kaisha | Roof rail and method for producing the roof rail |
| EP1522461A2 (en) | 1998-06-11 | 2005-04-13 | Asahi Kasei Kabushiki Kaisha | Roof rail and method for producing the roof rail |
| WO2001062479A1 (en) | 2000-02-24 | 2001-08-30 | Conix Corporation | Injection molding techniques utilizing fluid channels |
| EP1257411A1 (en) * | 2000-02-24 | 2002-11-20 | Conix Corporation | Injection molding techniques utilizing fluid channels |
| EP1257411A4 (en) * | 2000-02-24 | 2003-05-07 | Conix Corp | Injection molding techniques utilizing fluid channels |
| US6843954B2 (en) | 2000-02-24 | 2005-01-18 | Conix Corporation | Injection molding techniques utilizing fluid channels |
| US6998174B2 (en) | 2000-02-24 | 2006-02-14 | Conix Corporation | Integrated co-injection molded vehicle components and methods of making the same |
| EP1263574B1 (en) * | 2000-02-24 | 2016-05-18 | Conix Corporation | Method of making integrated co-injection molded vehicle components |
| WO2005018902A1 (en) * | 2003-08-22 | 2005-03-03 | Suzuka Fuji Xerox Co., Ltd. | Hollow molded product, method of manufacturing hollow molded product, and metal mold for hollow molding |
| EP2623290A1 (en) * | 2010-09-30 | 2013-08-07 | Asahi Kasei Chemicals Corporation | Injection-molded object |
| EP2623290A4 (en) * | 2010-09-30 | 2015-01-28 | Asahi Kasei Chemicals Corp | Injection-molded object |
| US9725587B2 (en) | 2010-09-30 | 2017-08-08 | Asahi Kasei Chemicals Corporation | Injection molded article |
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