JPH10211635A - Injection molding method - Google Patents
Injection molding methodInfo
- Publication number
- JPH10211635A JPH10211635A JP1715297A JP1715297A JPH10211635A JP H10211635 A JPH10211635 A JP H10211635A JP 1715297 A JP1715297 A JP 1715297A JP 1715297 A JP1715297 A JP 1715297A JP H10211635 A JPH10211635 A JP H10211635A
- Authority
- JP
- Japan
- Prior art keywords
- gate
- branch point
- resin
- mold
- weld
- 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
- B29C45/46—Means for plasticising or homogenising the moulding material or forcing it into the mould
- B29C45/57—Exerting after-pressure on the moulding material
-
- 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
- B29C45/0005—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor using fibre reinforcements
-
- 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
- B29C45/0025—Preventing defects on the moulded article, e.g. weld lines, shrinkage marks
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、熱可塑性樹脂の射
出成形方法に関するものであり、詳しくは、ウエルド周
辺の強度が高い成形品を製造可能な射出成形方法に関す
るものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for injection molding a thermoplastic resin, and more particularly to an injection molding method capable of producing a molded article having high strength around a weld.
【０００２】[0002]
【従来の技術】熱可塑性樹脂あるいは補強材を充填した
熱可塑性樹脂の射出成形によって比較的大きな成形品を
形成する場合には、たとえば図６の断面図で示したよう
な複数のゲート５３ａ，５３ｂを有する金型が用いら
れ、それらの複数ゲート５３ａ，５３ｂによってキャビ
ティ５４内へ略一斉に溶融樹脂が充填される。2. Description of the Related Art When a relatively large molded product is formed by injection molding of a thermoplastic resin or a thermoplastic resin filled with a reinforcing material, for example, a plurality of gates 53a and 53b as shown in the sectional view of FIG. The cavity is filled with molten resin substantially simultaneously by the plurality of gates 53a and 53b.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、図６の
ようにランナー５２の最終的な分岐点から各ゲート５３
ａ，５３ｂまでの長さが略等長である金型が用いられた
場合には、ランナー５２を通りゲート５３ａからキャビ
ティ５４内に充填された溶融樹脂の樹脂流Ａ１と、ゲー
ト５３ｂからキャビティ５４内に充填された溶融樹脂の
樹脂流Ａ２とが、キャビティ５４内の略中央部分（点Ｂ
の位置）において合流し、ウエルドが形成される。図７
は、ウエルドが形成された状態を示したものであり、ウ
エルドが形成された部分は、２つの樹脂流Ａ１，Ａ２の
先端が見かけ上密着しているものの、樹脂が一様に溶融
し合っておらず、樹脂あるいは樹脂中の補強材が２つの
樹脂流Ａ１，Ａ２の境界線であるウエルドライン５１を
挟んで別々に配向しているだけである。このため、成形
品のウエルド周辺の強度（たとえば、曲げ強度等）は、
熱可塑性樹脂本来の強度に比べて極端に低いものとな
る。また、ウエルドライン５１が明瞭に現れるため、成
形品の外観も不良となる。However, as shown in FIG. 6, each gate 53 is moved from the final branch point of the runner 52.
When a mold having a length equal to the lengths a and 53b is used, a resin flow A1 of the molten resin filled into the cavity 54 from the gate 53a through the runner 52 and a cavity 54 from the gate 53b are used. The resin flow A2 of the molten resin filled in the inside is substantially in the center portion of the cavity 54 (point B).
At the position (1), and a weld is formed. FIG.
Shows a state in which a weld is formed. In the portion where the weld is formed, although the tips of the two resin streams A1 and A2 seem to be in close contact with each other, the resin uniformly melts. The only difference is that the resin or the reinforcing material in the resin is separately oriented with the weld line 51, which is the boundary between the two resin flows A1 and A2, interposed therebetween. For this reason, the strength (for example, bending strength, etc.) around the weld of the molded product is
The strength is extremely lower than the original strength of the thermoplastic resin. In addition, since the weld line 51 clearly appears, the appearance of the molded product becomes poor.
【０００４】[0004]
【課題を解決するための手段】本発明の発明者らは、上
記ウエルド周辺の強度を向上させるべく鋭意検討した結
果、特定のランナー形状を有する金型を用いることによ
り、溶融樹脂の射出後にキャビティ内の圧力を一定に保
つ際にウエルド周辺の樹脂あるいは補強材の配向を乱す
ことが可能であり、ウエルド周辺の強度等が飛躍的に向
上することを見出し、本発明の射出成形方法を発明する
に至った。すなわち、本発明の構成は、複数のゲートが
設けられた金型による熱可塑性樹脂の射出成形方法であ
って、ランナーの最初の分岐点から各ゲートまでの長さ
が不等長であり、かつ分岐点から最も近いゲートまでの
長さが分岐点から最も遠いゲートまでの長さの１／２以
下である金型を用いることにより、射出後にキャビティ
内の圧力を一定に保つ保圧工程での樹脂の補填充填を、
前記分岐点から最も近いゲートから行うことにある。Means for Solving the Problems The inventors of the present invention have conducted intensive studies to improve the strength around the weld, and as a result, the use of a mold having a specific runner shape has resulted in a cavity after injection of the molten resin. It is possible to disturb the orientation of the resin or reinforcing material around the weld when the pressure inside is kept constant, and find that the strength around the weld is dramatically improved, and invent the injection molding method of the present invention. Reached. That is, the configuration of the present invention is a method of injection-molding a thermoplastic resin using a mold provided with a plurality of gates, wherein the length from the first branch point of the runner to each gate is unequal, and By using a mold in which the length from the branch point to the nearest gate is 1/2 or less of the length from the branch point to the farthest gate, the pressure in the cavity can be kept constant after injection. Filling and filling the resin
That is, the operation is performed from the gate closest to the branch point.
【０００５】また、前記ランナーの断面積が、キャビテ
ィの各ゲートの中間に位置した部分の断面積より小さい
ことにある。Further, the cross-sectional area of the runner is smaller than the cross-sectional area of a portion located between the gates of the cavity.
【０００６】さらに、前記熱可塑性樹脂が、結晶性熱可
塑性樹脂であることにある。なお、本発明でいうランナ
ーの最初の分岐点とは、金型のランナーの分岐点の内、
最もスプルー（あるいはノズル）に近い側の分岐点のこ
とである。Further, the thermoplastic resin is a crystalline thermoplastic resin. The first branch point of the runner in the present invention is a branch point of the mold runner,
This is the branch point closest to the sprue (or nozzle).
【０００７】[0007]
【発明の実施の形態】以下、本発明の射出成形方法、お
よび射出成形品について、図面に基づいて詳細に説明す
る。図１は、本発明の射出成形方法で使用する金型の一
例を断面図で示したものであり、金型は、ランナー２の
最初の分岐点Ｐから各ゲート３ａ，３ｂまでの長さが不
等長であり、かつ分岐点Ｐから近い方のゲート３ａまで
の長さが分岐点Ｐから遠い方のゲート３ｂまでの長さの
１／２になっている。かかる金型を用いて、熱可塑性樹
脂の射出成形をした場合には、図２の如く、ランナー２
を通りゲート３ａからキャビティ４内に充填された溶融
樹脂の樹脂流Ａ１と、ゲート３ｂからキャビティ４内に
充填された溶融樹脂の樹脂流Ａ２とが、キャビティ４内
の略中央部分（点Ｂの位置）において合流し、ウエルド
が形成される（なお、図２中の１は、ウエルドラインを
示したものである）。しかしながら、この金型において
は、ランナー２の基端からの樹脂圧力は、ゲート３ａの
方に伝わり易いため、射出後の保圧工程でキャビティ４
内の圧力を一定に保った場合には、キャビティ４内への
樹脂の補充充填が、主としてゲート３ａ側から行われ
る。このため、図３の如く、ウエルド周辺において、ゲ
ート３ａ側からゲート３ｂ側への樹脂の流入が生じるた
め、ウエルド周辺の強度が飛躍的に向上する。また、ウ
エルドラインも不明瞭で目立たないものとなる。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an injection molding method and an injection molded product of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view showing an example of a mold used in the injection molding method of the present invention. The mold has a length from the first branch point P of the runner 2 to each of the gates 3a and 3b. The length from the branch point P to the closer gate 3a is 等 of the length from the branch point P to the gate 3b farther from the branch point P. When injection molding of a thermoplastic resin is performed using such a mold, as shown in FIG.
Through the gate 3a, the resin flow A1 of the molten resin charged into the cavity 4 from the gate 3b, and the resin flow A2 of the molten resin charged into the cavity 4 from the gate 3b are substantially in the center portion of the cavity 4 (point B). At the position) and a weld is formed (1 in FIG. 2 indicates a weld line). However, in this mold, the resin pressure from the base end of the runner 2 is easily transmitted to the gate 3a.
When the internal pressure is kept constant, the resin is refilled into the cavity 4 mainly from the gate 3a side. For this reason, as shown in FIG. 3, resin flows from the gate 3a side to the gate 3b side around the weld, so that the strength around the weld is dramatically improved. Also, the weld line is unclear and inconspicuous.
【０００８】本発明で用いる金型は、ランナーの最初の
分岐点から各ゲートまでの長さが不等長であり、かつ分
岐点から最も近いゲートまでのランナー長が分岐点から
最も遠いゲートまでのランナー長の１／２以下のもので
あれば、図１の如き形状に限定されない。たとえば、図
４の如き３点ゲートのもの、あるいは４点以上のゲート
を有するものであっても良いし、図５の如く、円盤状、
円筒状のものであっても良い（なお、図５は、金型を上
から見た概略図である）。なお、ランナーの断面積が、
キャビティの各ゲートの中間に位置した部分（すなわ
ち、ウエルドが形成される部分）の断面積以下に形成さ
れたものであると、保圧工程において、ウエルド周辺
で、ランナーの分岐点から近いゲート側から遠いゲート
側への樹脂の流入度合いがより大きなものとなり、ウエ
ルド周辺の強度がより高くなるので好ましい。さらに、
ランナーの断面積がキャビティ内のウエルド形成部の断
面積の７０％以下であると、ウエルド周辺の強度が一層
向上するIn the mold used in the present invention, the length from the first branch point of the runner to each gate is unequal, and the runner length from the branch point to the nearest gate is from the branch point to the farthest gate. Is not limited to the shape as shown in FIG. For example, a three-point gate as shown in FIG. 4 or a gate having four or more gates may be used, or as shown in FIG.
It may be cylindrical (FIG. 5 is a schematic view of the mold as viewed from above). The cross-sectional area of the runner is
If the cavity is formed to be smaller than the cross-sectional area of a portion located in the middle of each gate of the cavity (that is, a portion where the weld is formed), in the pressure holding step, the gate side near the weld near the branch point of the runner near the weld. This is preferable because the degree of inflow of the resin to the gate side far from the gate becomes larger, and the strength around the weld becomes higher. further,
When the cross-sectional area of the runner is 70% or less of the cross-sectional area of the weld forming portion in the cavity, the strength around the weld is further improved.
【０００９】また、本発明の射出成形方法に用いる樹脂
は、熱可塑性樹脂であれば良く、その種類は特に限定さ
れない。しかしながら、ウエルド周辺により高い強度を
要求される結晶性熱可塑性樹脂を用いることが好まし
い。さらに、液晶ポリマーの様にウエルド周辺の強度が
低いものを用いると、改善効果が高いため特に望まし
い。[0009] The resin used in the injection molding method of the present invention may be a thermoplastic resin, and its type is not particularly limited. However, it is preferable to use a crystalline thermoplastic resin requiring higher strength around the weld. Furthermore, it is particularly desirable to use a material having a low strength around the weld, such as a liquid crystal polymer, because the effect of improvement is high.
【００１０】以下、実施例により、本発明についてさら
に具体的に説明する。 ［実施例１］図１の金型を用いて、ガラス繊維４０重量
％を配合したポリフェニレンサルファイド樹脂（以下、
単にＰＰＳ樹脂という）の射出成形を行った。なお、金
型は、上述の如く、分岐点Ｐ（ランナー２の最初の分岐
点）から近いゲート３ａまでの長さが分岐点Ｐから遠い
ゲート３ｂまでの長さの１／２になっているとともに、
ランナー２の内径、およびキャビティ４の内径が、それ
ぞれ、幅（紙面に垂直な方向）５mm×厚さ（上下方向）
４mm、幅２５mm×厚さ５mmになっており、ランナー２の
断面積が、キャビティ４の各ゲート３ａ，３ｂの中間に
位置した部分の断面積より小さくなっている（ランナー
２の断面積／キャビティ４の断面積＝０．１６）。ま
た、キャビティ４内の長さ（左右方向）は、７０mmに設
計されている。そして、樹脂温度３２０℃、金型温度１
５０℃の温度条件にて、ＰＰＳ樹脂をキャビティ４内に
射出し、完全に充填した直後、キャビティ４内の圧力を
６０MPa の一定圧力に保った。しかる後、金型から成形
品を取り出すことによって、実施例１の射出成形品を得
た。Hereinafter, the present invention will be described more specifically with reference to examples. Example 1 Using the mold of FIG. 1, a polyphenylene sulfide resin containing 40% by weight of glass fiber (hereinafter referred to as “polyphenylene sulfide resin”) was used.
Injection molding (hereinafter simply referred to as PPS resin). As described above, the length of the mold from the branch point P (the first branch point of the runner 2) to the gate 3a close to the branch point P is half the length from the branch point P to the gate 3b far from the branch point P. With
The inner diameter of the runner 2 and the inner diameter of the cavity 4 are each 5 mm in width (in the direction perpendicular to the paper surface) × thickness (in the vertical direction).
4 mm, width 25 mm × thickness 5 mm, and the cross-sectional area of the runner 2 is smaller than the cross-sectional area of a portion of the cavity 4 located between the gates 3a and 3b (cross-sectional area of the runner 2 / cavity). 4 = 0.16). The length (left-right direction) inside the cavity 4 is designed to be 70 mm. Then, a resin temperature of 320 ° C. and a mold temperature of 1
At a temperature of 50 ° C., the PPS resin was injected into the cavity 4 and immediately after being completely filled, the pressure in the cavity 4 was maintained at a constant pressure of 60 MPa. Thereafter, the molded product was taken out of the mold to obtain the injection molded product of Example 1.
【００１１】［実施例２］分岐点Ｐから近いゲート３ａ
までの長さが分岐点Ｐから遠いゲート３ｂまでの長さの
１／３となるように金型の形状を変更した以外は、実施
例１と同様にして、実施例２の射出成形品を得た。[Embodiment 2] Gate 3a near branch point P
Except that the shape of the mold was changed so that the length to the gate 3b far from the branch point P was 1/3. Obtained.
【００１２】［実施例３］分岐点Ｐから近いゲート３ａ
までの長さが分岐点Ｐから遠いゲート３ｂまでの長さの
１／４となるように金型の形状を変更した以外は、実施
例１と同様にして、実施例３の射出成形品を得た。[Embodiment 3] Gate 3a close to branch point P
The injection-molded article of Example 3 was manufactured in the same manner as in Example 1 except that the shape of the mold was changed so that the length to the gate 3b far from the branch point P was 1/4. Obtained.
【００１３】［実施例４］分岐点Ｐから近いゲート３ａ
までの長さが分岐点Ｐから遠いゲート３ｂまでの長さの
１／５となるように金型の形状を変更した以外は、実施
例１と同様にして、実施例４の射出成形品を得た。[Embodiment 4] Gate 3a close to branch point P
The injection molded product of Example 4 was manufactured in the same manner as in Example 1 except that the shape of the mold was changed so that the length to the gate 3b far from the branch point P was 1/5. Obtained.
【００１４】［比較例１］図６の如く、分岐点Ｐから各
ゲート３ａ，３ｂまでの長さが等しくなるように金型の
形状を変更した以外は、実施例１と同様にして、比較例
１の射出成形品を得た。[Comparative Example 1] As shown in FIG. 6, a comparison was made in the same manner as in Example 1 except that the shape of the mold was changed so that the length from the branch point P to each of the gates 3a and 3b was equal. The injection molded product of Example 1 was obtained.
【００１５】［比較例２］分岐点Ｐから近いゲート３ａ
までの長さが分岐点Ｐから遠いゲート３ｂまでの長さの
２／３となるように金型の形状を変更した以外は、実施
例１と同様にして、比較例２の射出成形品を得た。Comparative Example 2 Gate 3a Close to Branch Point P
The injection molded product of Comparative Example 2 was manufactured in the same manner as in Example 1 except that the shape of the mold was changed so that the length to the gate 3b far from the branch point P was 2/3. Obtained.
【００１６】［実施例５］金型のキャビティ４の内径、
およびランナー２の内径を、それぞれ、幅２５mm×厚さ
５mm、幅２５mm×厚さ５mmに変更した以外は、実施例１
と同様にして、実施例５の射出成形品を得た。[Embodiment 5] The inner diameter of the cavity 4 of the mold,
Example 1 except that the inner diameter of the runner 2 was changed to 25 mm width × 5 mm thickness and 25 mm width × 5 mm thickness, respectively.
In the same manner as in the above, an injection molded product of Example 5 was obtained.
【００１７】［実施例６〜９］射出成形の樹脂材料を、
ガラス繊維３０重量％を配合した液晶ポリマー（以下、
単にＬＣＰという）に変更するとともに、射出成形の温
度条件を樹脂温度２９０℃、金型温度１２０℃に変更し
た以外は、それぞれ、実施例１〜４と同様にして、実施
例６〜９の射出成形品を得た。Examples 6 to 9 The injection molding resin material was
Liquid crystal polymer blended with 30% by weight of glass fiber
LCP) and the temperature conditions of injection molding were changed to resin temperature of 290 ° C. and mold temperature of 120 ° C., respectively. A molded product was obtained.
【００１８】［比較例３，４］ガラス繊維４０重量％を
配合したＬＣＰを用いた以外は、それぞれ、比較例１，
２と同様にして、比較例３，４の射出成形品を得た。[Comparative Examples 3 and 4] Comparative Examples 1 and 4 were used except that LCP containing 40% by weight of glass fiber was used.
In the same manner as in Example 2, injection molded products of Comparative Examples 3 and 4 were obtained.
【００１９】実施例１〜９、比較例１〜４で得られた射
出成形品のウエルド周辺の曲げ強度を測定し、その測定
結果を以下の表１及び表２に示した。表１から明らかな
ように、分岐点Ｐから近いゲート３ａまでの長さが分岐
点Ｐから遠いゲート３ｂまでの長さの１／２以下である
金型を用いてＰＰＳ樹脂を射出成形した場合には、射出
成形品のウエルド周辺の曲げ強度が飛躍的に向上する
（約１．５〜１．７倍、実施例１〜４および比較例１，
２参照）。また、表２から明らかなように、ＬＣＰを用
いた場合には、射出成形品のウエルド周辺の曲げ強度の
向上が、より顕著なものとなる（約２．２〜２．４倍、
実施例６〜９および比較例３，４参照）。さらに、金型
のランナー２の断面積が、キャビティ４の各ゲート３
ａ，３ｂの中間に位置した部分（すなわち、ウエルドが
形成される部分）の断面積より小さい場合にも、ウエル
ド周辺の曲げ強度の向上が、より顕著なものとなる（実
施例１、実施例５参照）。The bending strengths around the welds of the injection molded products obtained in Examples 1 to 9 and Comparative Examples 1 to 4 were measured, and the measurement results are shown in Tables 1 and 2 below. As is apparent from Table 1, when the PPS resin is injection-molded using a mold in which the length from the branch point P to the gate 3a close to the branch point P is 1/2 or less of the length from the branch point P to the gate 3b far from the branch point P. In Example 1, the bending strength around the weld of the injection-molded article is dramatically improved (about 1.5 to 1.7 times, Examples 1 to 4 and Comparative Examples 1 and 2).
2). Also, as is clear from Table 2, when LCP is used, the improvement in bending strength around the weld of the injection-molded article becomes more remarkable (about 2.2 to 2.4 times,
Examples 6 to 9 and Comparative Examples 3 and 4). Furthermore, the cross-sectional area of the mold runner 2 is
Even when the cross-sectional area is smaller than that of the portion located in the middle between a and 3b (that is, the portion where the weld is formed), the improvement in bending strength around the weld becomes more remarkable (Examples 1 and 2). 5).
【００２０】[0020]
【表１】 [Table 1]
【表２】 [Table 2]
【００２１】なお、上記実施例は単なる一例であり、射
出時の樹脂温度、金型温度、保圧工程時の圧力等の射出
成形条件、射出成形に用いる樹脂材料等は、上記実施例
の態様に何ら限定されず、本発明の趣旨を逸脱しない範
囲内で適宜変更することができる。The above embodiment is merely an example, and the injection molding conditions such as the resin temperature during injection, the mold temperature, and the pressure during the pressure-holding step, and the resin material used for injection molding are the same as those of the above embodiment. The present invention is not limited in any way, and can be appropriately changed without departing from the spirit of the present invention.
【００２２】[0022]
【発明の効果】本発明の射出成形方法によれば、ウエル
ド周辺の強度がきわめて高く、しかもウエルドラインが
目立たず外観の良好な射出成形品を非常に容易に製造す
ることができる。According to the injection molding method of the present invention, it is possible to very easily produce an injection-molded article having a very high strength around the weld and a good appearance without a noticeable weld line.
【図１】本発明で用いる金型の一例を示す説明図であ
る。FIG. 1 is an explanatory view showing an example of a mold used in the present invention.
【図２】ウエルド周辺の樹脂あるいは樹脂中の補強材の
配向状態を示す説明図である。FIG. 2 is an explanatory view showing an orientation state of a resin around a weld or a reinforcing material in the resin.
【図３】ウエルド周辺の樹脂あるいは樹脂中の補強材の
配向状態を示す説明図である。FIG. 3 is an explanatory diagram showing an orientation state of a resin around a weld or a reinforcing material in the resin.
【図４】本発明で用いる金型の一例を示す説明図であ
る。FIG. 4 is an explanatory view showing an example of a mold used in the present invention.
【図５】本発明で用いる金型の一例を示す説明図であ
る。FIG. 5 is an explanatory view showing an example of a mold used in the present invention.
【図６】従来の金型を示す説明図である。FIG. 6 is an explanatory view showing a conventional mold.
【図７】ウエルド周辺の樹脂あるいは樹脂中の補強材の
配向状態を示す説明図である。FIG. 7 is an explanatory view showing an orientation state of a resin around a weld or a reinforcing material in the resin.
１・・ウエルドライン、２・・ランナー、３，３ａ，３
ｂ・・ゲート、４・・キャビティ、５１・・ウエルドラ
イン、５２・・ランナー、５３ａ，５３ｂ・・ゲート、
５４・・キャビティ。1. Weld line, 2. Runner, 3, 3a, 3
b · gate, 4 · cavity, 51 · weld line, 52 · runner, 53a, 53b · gate,
54 cavity.
Claims (3)
可塑性樹脂の射出成形方法であって、 ランナーの最初の分岐点から各ゲートまでの長さが不等
長でありかつ分岐点から最も近いゲートまでの長さが分
岐点から最も遠いゲートまでの長さの１／２以下である
金型を用いることにより、射出工程終了後にキャビティ
内の圧力を一定に保つ保圧工程での樹脂の補填充填を、
前記分岐点から最も近いゲートから行うことを特徴とす
る射出成形方法。1. A method for injection-molding a thermoplastic resin using a mold provided with a plurality of gates, wherein a length from a first branch point of a runner to each gate is unequal, and a distance from the branch point is the largest. By using a mold whose length to the near gate is 1/2 or less of the length from the branch point to the farthest gate, the resin in the pressure-holding step to keep the pressure in the cavity constant after the end of the injection step Make-up filling
The injection molding method is performed from a gate closest to the branch point.
各ゲートの中間に位置した部分の断面積より小さいこと
を特徴とする請求項１に記載の射出成形方法。2. The injection molding method according to claim 1, wherein a cross-sectional area of the runner is smaller than a cross-sectional area of a portion of the cavity located between the gates.
脂であることを特徴とする請求項１、または２に記載の
射出成形方法。3. The injection molding method according to claim 1, wherein the thermoplastic resin is a crystalline thermoplastic resin.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1715297A JPH10211635A (en) | 1997-01-30 | 1997-01-30 | Injection molding method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1715297A JPH10211635A (en) | 1997-01-30 | 1997-01-30 | Injection molding method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH10211635A true JPH10211635A (en) | 1998-08-11 |
Family
ID=11936021
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1715297A Pending JPH10211635A (en) | 1997-01-30 | 1997-01-30 | Injection molding method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH10211635A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001341153A (en) * | 2000-03-31 | 2001-12-11 | Sumitomo Chem Co Ltd | Injection molding |
| JP2009226841A (en) * | 2008-03-25 | 2009-10-08 | Tokai Rubber Ind Ltd | Resin molding method, resin molded product, and mold |
| CN113246398A (en) * | 2020-02-08 | 2021-08-13 | 株式会社小糸制作所 | Injection-molded article, and molding method and molding apparatus therefor |
| CN117325389A (en) * | 2023-09-27 | 2024-01-02 | 广东联塑科技实业有限公司 | Pipe fitting injection molding method, mold and pipe fitting |
-
1997
- 1997-01-30 JP JP1715297A patent/JPH10211635A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001341153A (en) * | 2000-03-31 | 2001-12-11 | Sumitomo Chem Co Ltd | Injection molding |
| JP2009226841A (en) * | 2008-03-25 | 2009-10-08 | Tokai Rubber Ind Ltd | Resin molding method, resin molded product, and mold |
| JP4613971B2 (en) * | 2008-03-25 | 2011-01-19 | 東海ゴム工業株式会社 | Resin molding method, resin molded product, and mold |
| CN113246398A (en) * | 2020-02-08 | 2021-08-13 | 株式会社小糸制作所 | Injection-molded article, and molding method and molding apparatus therefor |
| CN117325389A (en) * | 2023-09-27 | 2024-01-02 | 广东联塑科技实业有限公司 | Pipe fitting injection molding method, mold and pipe fitting |
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