JP3815957B2 - Gate structure for injection molding resin mold - Google Patents

Gate structure for injection molding resin mold Download PDF

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Publication number
JP3815957B2
JP3815957B2 JP2000260078A JP2000260078A JP3815957B2 JP 3815957 B2 JP3815957 B2 JP 3815957B2 JP 2000260078 A JP2000260078 A JP 2000260078A JP 2000260078 A JP2000260078 A JP 2000260078A JP 3815957 B2 JP3815957 B2 JP 3815957B2
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JP
Japan
Prior art keywords
gate
product
mold
resin
sub
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.)
Expired - Fee Related
Application number
JP2000260078A
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Japanese (ja)
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JP2002067087A (en
Inventor
豊蔵 中島
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Honda Motor Co Ltd
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Honda Motor Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Honda Motor Co Ltd filed Critical Honda Motor Co Ltd
Priority to JP2000260078A priority Critical patent/JP3815957B2/en
Publication of JP2002067087A publication Critical patent/JP2002067087A/en
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Description

【0001】
【発明の属する技術分野】
本発明は、合成樹脂製品を射出成形する際使用される耐熱樹脂型のゲート構造に関する。
【0002】
【従来の技術】
従来、合成樹脂製品を製造する射出成形型として、例えば特開昭51−111862号や特開昭57−163519号のような耐熱性樹脂型が知られており、一般的に耐久性が悪いため、試作品等の少数製品の作製用に使用されることが多かったが、近年では、耐久性樹脂の開発により大量生産向けの成形型としても使用されるようになっている。
【0003】
【発明が解決しようとする課題】
ところが、このような樹脂型で、例えば図4に示すようなランナー51からゲート52を通して製品部53に溶融樹脂を射出して成形すると、ランナー51の先端が小径に絞られているため、溶融樹脂の流速が上がり、同部の型温が上昇する傾向にある。
一方、樹脂型は一般的に金属製型等に較べて熱伝導率及び型強度が低いため、射出が繰り返されると樹脂型のゲート部やゲート部に連なる製品成形部等にクラックが発生し、このクラックが製品部53にクラック跡cとして転写されると成形不良となるため、試作品や表面が平坦な製品等の場合、ゲート52を切断後、サンドペーパ等で修正しているが、例えば表面にしぼ模様を形成したような場合は、サンドペーパ等による修正が不可能である。
【0004】
そこで本発明は、樹脂型のゲート部附近のクラック等に起因する製品部の成形不良を防止することを目的とする。
【0005】
【課題を解決するための手段】
上記目的を達成するため本発明は、ランナー部やゲート部や製品成形部等が耐熱樹脂によって形成される射出成形樹脂型のゲートの構造において、ゲート部と製品成形部との間に所定長さのサブゲート部を設けるようにした。
【0006】
このようにゲート部と製品成形部との間にサブゲート部を設け、型温上昇によって不具合が生じ易いゲート部と製品成形部との距離を離すことにより、成形不良等のダメージが製品部に及ばないようにし、サブゲート部で成形されるサブゲートは成形後切除する。
このため、サブゲート部の長さは、ゲート部の型温が上昇することによりゲート部附近に発生するクラックが製品部にクラック跡として転写されないように設定し、射出圧や溶融樹脂の種類や製品形状や耐熱樹脂の特性等を勘案して適切な長さに設定する。
【0007】
た、サブゲート部を、ゲート部より幅広の偏平状にした。このように偏平状にすることにより、ゲート切断後のゲート跡を目立たなくすることが出来、またゲート部より幅広のサブゲート部にすることで、溶融樹脂の流れを円滑にすることが出来る。
【0008】
【発明の実施の形態】
本発明の実施の形態について添付した図面に基づき説明する。
ここで図1は本発明に係る射出成形型の説明図、図2はゲート構造を説明するための成形品の説明図、図3は耐久性の検証試験を行った時の説明図である。
【0009】
本発明に係る射出成形樹脂型用ゲートは、樹脂型により射出成形を繰り返すことによりゲート附近の樹脂型にクラックが発生し、このクラックに起因する成形不良が製品部に及ぶのを防止出来るようにされ、例えば図1に示すような射出成形樹脂型1に適用されている。
【0010】
この射出成形樹脂型1は、固定型2と可動型3を備え、これら固定型2と可動型3は、それぞれZA等の材質からなる本体部2a、3aと、エポキシ等の耐熱樹脂からなる樹脂層部2b、3bから構成されるとともに、固定型2には、溶融樹脂を注入するスプルーブッシュ4が設けられ、可動型3には突き出し機構5が設けられている。
【0011】
そして、固定型2と可動型3が型締めされると、スプルー部6の下流に、ランナー部やゲート部やサブゲート部等を介して製品成形部7が形成されるようにしており、このような射出成形樹脂型1に溶融樹脂を射出して図2に示すような成形品8を成形すると、ランナ部に対応するランナ9と、ゲート部に対応するゲート10と、サブゲート部に対応するサブゲート11と、製品成形部に対応する製品部12が成形されるようにしており、また製品部12には、しぼ模様等の模様が刻設されるようにしている。
【0012】
ここで、サブゲート11の形状は、ゲート10より幅広で且つ偏平状にされており、また、その長さは、ゲート部の型温上昇に伴うストレスが製品部12に及ばないような長さに設定されている。
ここで、サブゲート11を偏平状にしているのは、切断後のゲート跡を目立たなくするためであり、またゲート10より幅広にしているのは、溶融樹脂の円滑な流れを確保するためである。
【0013】
以上のような本発明のゲート構造の効果について、図3に示すように、本発明に係るゲート10、サブゲート11の構造と、従来構造のゲート52の二つが形成されるようにして比較検証した。
【0014】
この結果、従来構造のゲート52では、1000ショットから固定型と可動型の両方のゲート部附近にクラックが発生し、製品部12に悪影響を与えるようになったが、本発明に係るゲート構造では5万ショット繰り返しても上記のような不具合が発生しなかった。
そこで本発明の有効性が確認された。
【0015】
尚、本発明は以上のような実施形態に限定されるものではない。本発明の特許請求の範囲に記載した事項と実質的に同一の構成を有し、同一の作用効果を奏するものは本発明の技術的範囲に属する。
例えば樹脂型の構成や製品形状等は一例であり、またしぼ模様等のない製品にも適用可能である。
【0016】
【発明の効果】
以上のように本発明に係る射出成形樹脂型用ゲート構造は、ランナー部の下流のゲート部と製品成形部との間に、ゲート部の型温が上昇することによりゲート部附近に発生するクラックが製品部にクラック跡として転写されない長さに設定されたサブゲート部を設けたので、ゲート部の型温が上昇しても製品部にダメージを受けるような不具合が抑制される。
また、サブゲート部を、ゲート部より幅広で且つ偏平状にしたので、ゲート切断後のゲート跡を目立たなくすることが出来、しかも溶融樹脂の流れを円滑にすることが出来る。
【図面の簡単な説明】
【図1】本発明に係る射出成形型の説明図
【図2】ゲート構造を説明するための成形品の説明図
【図3】耐久性の検証試験を行った時の説明図
【図4】従来のゲートの不具合状態を説明する説明図
【符号の説明】
1…射出成形樹脂型、7…製品成形部、8…成形品、9…ランナー、10…ゲート、11…サブゲート、12…製品部。
[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat-resistant resin type gate structure used when injection molding a synthetic resin product.
[0002]
[Prior art]
Conventionally, as an injection mold for producing a synthetic resin product, for example, heat-resistant resin molds such as JP-A-51-111862 and JP-A-57-163519 are known and generally have poor durability. However, in recent years, it has been used as a mold for mass production due to the development of a durable resin.
[0003]
[Problems to be solved by the invention]
However, with such a resin mold, for example, when the molten resin is injected from the runner 51 as shown in FIG. 4 into the product portion 53 through the gate 52 and molded, the tip of the runner 51 is narrowed to a small diameter. There is a tendency that the flow rate of the mold increases and the mold temperature of the same part increases.
On the other hand, since the resin mold generally has a lower thermal conductivity and mold strength than a metal mold or the like, when the injection is repeated, cracks occur in the resin molded gate part and the product molded part connected to the gate part, When this crack is transferred to the product portion 53 as a crack mark c, a molding failure occurs. Therefore, in the case of a prototype or a product with a flat surface, the gate 52 is cut and then corrected with sandpaper or the like. In the case where a wrinkle pattern is formed, correction by sandpaper or the like is impossible.
[0004]
Therefore, an object of the present invention is to prevent defective molding of a product part due to a crack or the like near a resin-type gate part.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an injection molding resin type gate structure in which a runner part, a gate part, a product molding part, etc. are formed of a heat-resistant resin, and has a predetermined length between the gate part and the product molding part. The sub-gate part was provided.
[0006]
In this way, by providing a sub-gate part between the gate part and the product molding part and separating the distance between the gate part and the product molding part, which is likely to cause problems due to a rise in mold temperature, damage such as molding defects is applied to the product part. The sub-gate formed at the sub-gate portion is cut off after forming.
For this reason, the length of the sub- gate part is set so that cracks generated in the vicinity of the gate part due to an increase in the mold temperature of the gate part are not transferred to the product part as crack marks , and the injection pressure, type of molten resin, and product The length should be set to an appropriate length considering the shape and characteristics of the heat-resistant resin.
[0007]
In addition, the sub-gate part, was in wide flat from the gate portion. By making it flat like this, the gate trace after cutting the gate can be made inconspicuous, and by making the sub-gate portion wider than the gate portion, the flow of the molten resin can be made smooth.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the accompanying drawings.
1 is an explanatory view of an injection mold according to the present invention, FIG. 2 is an explanatory view of a molded product for explaining a gate structure, and FIG. 3 is an explanatory view when a durability verification test is performed.
[0009]
The injection molding resin mold gate according to the present invention can prevent the resin mold near the gate from cracking by repeating injection molding with the resin mold and prevent the molding defect due to the crack from reaching the product part. For example, it is applied to an injection molding resin mold 1 as shown in FIG.
[0010]
The injection molding resin mold 1 includes a fixed mold 2 and a movable mold 3. The fixed mold 2 and the movable mold 3 are each a main body 2a, 3a made of a material such as ZA, and a resin made of a heat resistant resin such as epoxy. The fixed mold 2 is provided with a sprue bush 4 for injecting molten resin, and the movable mold 3 is provided with a protruding mechanism 5.
[0011]
And when the fixed mold | type 2 and the movable mold | type 3 are clamped, the product shaping | molding part 7 is formed in the downstream of the sprue part 6 via a runner part, a gate part, a subgate part, etc., like this When a molten resin is injected into the injection molding resin mold 1 to form a molded product 8 as shown in FIG. 2, a runner 9 corresponding to the runner portion, a gate 10 corresponding to the gate portion, and a subgate corresponding to the subgate portion 11 and a product part 12 corresponding to the product forming part are formed, and a pattern such as a wrinkle pattern is engraved on the product part 12.
[0012]
Here, the shape of the sub-gate 11 is wider and flattened than the gate 10, and the length thereof is such that the stress due to the rise in mold temperature of the gate portion does not reach the product portion 12. Is set.
Here, the reason why the sub-gate 11 is flattened is to make the gate trace after cutting inconspicuous, and the reason why it is wider than the gate 10 is to ensure a smooth flow of the molten resin. .
[0013]
As shown in FIG. 3, the effects of the gate structure of the present invention as described above were compared and verified by forming two structures of the gate 10 and the sub-gate 11 according to the present invention and the gate 52 of the conventional structure. .
[0014]
As a result, in the conventional gate 52, cracks occurred from 1000 shots in the vicinity of both the fixed type and the movable type gate parts, and the product part 12 was adversely affected. However, in the gate structure according to the present invention, Even when 50,000 shots were repeated, the above-described problems did not occur.
Therefore, the effectiveness of the present invention was confirmed.
[0015]
The present invention is not limited to the above embodiment. What has substantially the same configuration as the matters described in the claims of the present invention and exhibits the same operational effects belongs to the technical scope of the present invention.
For example, the configuration of the resin mold, the product shape, and the like are examples, and the present invention can also be applied to products having no wrinkle pattern.
[0016]
【The invention's effect】
As described above, the injection molded resin mold gate structure according to the present invention has a crack generated near the gate portion when the mold temperature of the gate portion rises between the gate portion downstream of the runner portion and the product molding portion. There is provided with the sub-gate section is set to a length that is not transcribed as crack remains in the product portion, defects such as mold temperature of the gate portion is damaged in the product portion is also increased is suppressed.
Further, the sub-gate portion, since the and flat at wider than the gate portion, can be inconspicuous gate mark after the gate cutting, yet can be smoothly flow of the molten resin.
[Brief description of the drawings]
FIG. 1 is an explanatory view of an injection mold according to the present invention. FIG. 2 is an explanatory view of a molded product for explaining a gate structure. FIG. 3 is an explanatory view when a durability verification test is performed. Explanatory drawing explaining the failure status of conventional gates [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Injection molding resin mold, 7 ... Product molding part, 8 ... Molded product, 9 ... Runner, 10 ... Gate, 11 ... Sub-gate, 12 ... Product part.

Claims (1)

ランナー部やゲート部や製品成形部が耐熱樹脂によって形成される射出成形樹脂型のゲート構造であって、ゲート部と製品成形部の間にサブゲート部を設け、このサブゲート部の長さは、ゲート部の型温が上昇することによりゲート部附近に発生するクラックが製品部にクラック跡として転写されないように設定され、前記サブゲート部の形状は、ゲート部より幅広で且つ偏平状であることを特徴とする射出成形樹脂型用ゲート構造。The runner part, gate part, and product molded part are injection-molded resin type gate structures formed of heat-resistant resin, and a sub-gate part is provided between the gate part and the product molded part. The length of this sub-gate part is the gate It is set so that cracks generated near the gate part due to the rise in mold temperature of the part are not transferred to the product part as crack marks, and the shape of the sub-gate part is wider and flatter than the gate part. An injection molded resin mold gate structure.
JP2000260078A 2000-08-30 2000-08-30 Gate structure for injection molding resin mold Expired - Fee Related JP3815957B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2000260078A JP3815957B2 (en) 2000-08-30 2000-08-30 Gate structure for injection molding resin mold

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2000260078A JP3815957B2 (en) 2000-08-30 2000-08-30 Gate structure for injection molding resin mold

Publications (2)

Publication Number Publication Date
JP2002067087A JP2002067087A (en) 2002-03-05
JP3815957B2 true JP3815957B2 (en) 2006-08-30

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Country Status (1)

Country Link
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Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6048714B1 (en) * 2016-03-25 2016-12-21 有限会社小椋製作所 Injection mold and gate bush

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4294792A (en) * 1978-10-27 1981-10-13 Universal Optical Company, Inc. Molded plastic parts, particularly spin-cast plastic parts for eyeglass frames
JPH07115378B2 (en) * 1987-09-11 1995-12-13 三菱瓦斯化学株式会社 Method for manufacturing molded article having mirror surface
JPH0725103B2 (en) * 1990-07-26 1995-03-22 オリンパス光学工業株式会社 Method of molding optical molded body having mirror surface
JPH0595014A (en) * 1991-10-02 1993-04-16 Hitachi Ltd Formation method of sealing body
JP3218587B2 (en) * 1994-04-28 2001-10-15 三菱マテリアル株式会社 Ring gate mold
JPH1095031A (en) * 1996-09-24 1998-04-14 Dainippon Printing Co Ltd Method and mold for molding information card and information card
JPH11291296A (en) * 1998-04-07 1999-10-26 Nissan Motor Co Ltd Injection mold

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