JP2661656B2 - Injection molding method - Google Patents

Injection molding method

Info

Publication number
JP2661656B2
JP2661656B2 JP4273823A JP27382392A JP2661656B2 JP 2661656 B2 JP2661656 B2 JP 2661656B2 JP 4273823 A JP4273823 A JP 4273823A JP 27382392 A JP27382392 A JP 27382392A JP 2661656 B2 JP2661656 B2 JP 2661656B2
Authority
JP
Japan
Prior art keywords
resin
filling
cavity
injection
injection molding
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
JP4273823A
Other languages
Japanese (ja)
Other versions
JPH05200801A (en
Inventor
富男 飯野
千章 森
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
Original Assignee
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 JP4273823A priority Critical patent/JP2661656B2/en
Publication of JPH05200801A publication Critical patent/JPH05200801A/en
Application granted granted Critical
Publication of JP2661656B2 publication Critical patent/JP2661656B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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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
    • B29C45/56—Means for plasticising or homogenising the moulding material or forcing it into the mould using mould parts movable during or after injection, e.g. injection-compression moulding
    • 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

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)

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【産業上の利用分野】本発明は、樹脂成形品の射出成形
において成形収縮に起因するヒケ等の発生を防止するよ
うにした射出成形方法の改良に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an injection molding method for preventing the occurrence of sink marks or the like due to molding shrinkage in injection molding of a resin molded product.

【０００２】[0002]

【従来の技術】従来、例えば熱可塑性樹脂の射出成形に
おいて、ヒケ等の成形不良を防止する成形法として特公
昭３９―１８２５号のような方法が知られている。この
方法は樹脂の射出成形に際しその一部に突出部を形成
し、加圧成形中に冷却効果が未だ成形物の芯層部にまで
波及しない時期に該突出部を加圧し、射出圧に頼らず内
圧を高めることによって冷却収縮等に起因するヒケの発
生等を防止するようにしたものである。そしてかかる方
法は、比較的肉厚の厚い成形品の場合は溶融樹脂の流れ
がスムースであるため加圧が有効に作用し、射出圧や型
締圧を高める必要がなくなるという効果を有していた。
一方、かかるヒケ等防止技術にあって加圧のタイミング
に関する技術も開示されており、例えば特開昭６３―１
５７２１号は、キャビティに注入される溶融樹脂の充填
完了時をセンサによって把握し、この充填完了にタイミ
ングを合せてキャビティに連通する空隙部内の溶融樹脂
に向けて押出しピンを突き出し、同部から圧力を加えて
製品のヒケ防止を図っている。2. Description of the Related Art Conventionally, for example, in injection molding of a thermoplastic resin, a method such as Japanese Patent Publication No. 39-1825 has been known as a molding method for preventing molding defects such as sink marks. In this method, a protrusion is formed on a part of the resin during injection molding, and the protrusion is pressurized at a time when the cooling effect does not yet reach the core layer of the molded product during pressure molding, and the injection pressure is used. By increasing the internal pressure, the occurrence of sink marks due to cooling shrinkage and the like is prevented. Such a method has the effect that in the case of a molded article having a relatively large thickness, the flow of the molten resin is smooth, so that the pressurization works effectively and it is not necessary to increase the injection pressure or the mold clamping pressure. Was.
On the other hand, a technique relating to the timing of pressurization in such a technique for preventing sink marks and the like is disclosed, for example, in JP-A-63-1.
No. 5721 uses a sensor to detect when the filling of the molten resin to be injected into the cavity is completed, and pushes out an extrusion pin toward the molten resin in the cavity communicating with the cavity in time with the completion of the filling, and pressurizes from the same. To prevent sink marks on the product.

【０００３】[0003]

【発明が解決しようとする課題】しかしながら、上記の
ような方法の場合は、溶融樹脂の充填完了後に前記空隙
部内の溶融樹脂を押圧するようにしているため、ゲート
から比較的近く溶融樹脂の充填の早い空隙部と、溶融樹
脂が最後に充填される空隙部との樹脂硬化速度が異な
り、押圧の効果が異なって所望の効果が得られないとい
う問題があった。つまり、硬化を始めて硬くなった部分
をいくら押しても既に樹脂は均一に広がらず、内部応力
が発生してソリ等の変形を生じるばかりでなく、この硬
い部分の影響を受けて軟らかい部分まで押込み不足にな
ったりするからである。そして、かかる不具合を無くそ
うとして各押出しピンごとにセンサを設け、このセンサ
によって別個に押出しピンを作動させようとするとコス
トアップの原因になるという問題があった。However, in the case of the above-mentioned method, since the molten resin in the gap is pressed after the filling of the molten resin is completed, the filling of the molten resin is relatively close to the gate. There is a problem that the resin curing speed is different between the void portion having a high temperature and the void portion filled with the molten resin last, and the desired effect cannot be obtained due to a different pressing effect. In other words, no matter how much the hardened part is pushed after the hardening, the resin does not spread evenly already, and not only does internal stress occur, causing deformation such as warping, but also due to the effect of the hard part, insufficient pushing of the soft part Because it becomes. In order to eliminate such a problem, a sensor is provided for each push-out pin, and if the push-out pins are separately operated by this sensor, there is a problem that the cost is increased.

【０００４】[0004]

【課題を解決するための手段】かかる課題を解決するた
め本発明は、金型のキャビティ内に充填した溶融樹脂を
押圧手段によって加圧し成形するようにした射出成形法
において、押圧手段は、金型のゲート近傍からキャビテ
ィの充填末端側に向けてランナ溝部として延出する樹脂
溜め部に設けられ、この押圧手段による押圧動作は、樹
脂のキャビティへの必要充填量の７５％が射出注入され
た以降に開始し、且つキャビティへの樹脂充填完了後１
秒以内に終了させるようにした。 According to the present invention, there is provided an injection molding method in which a molten resin filled in a cavity of a mold is pressed and molded by a pressing means. The pressing means is provided in a resin reservoir extending from the vicinity of the gate of the mold as a runner groove toward the filling end of the cavity. The pressing operation is such that 75% of the required filling amount of the resin into the cavity is injected and injected.
Start on or after, and after completion the resin filling into the cavity 1
Finished within seconds .

【０００５】[0005]

【作用】ゲート近傍からキャビティの充填末端側に向け
て延出するランナ溝部には、射出とほぼ同時に溶融樹脂
が満たされ、しかも押圧手段はこのランナ溝部に設けら
れているため、充填完了を検知するセンサがなくても充
填完了前から押圧が可能となる。又、充填開始から充填
完了までランナ溝部には熱い溶融樹脂が供給され続けて
いるので、均一なバランスのとれた加圧が可能である。
又、押圧手段による押圧を充填完了前から充填完了後ま
でとすることで、射出圧を増加させたと同等の効果が得
られ、効率の良い加圧が可能である。特に本発明は、押
圧手段による押圧動作は、樹脂のキャビティへの必要充
填量の７５％が射出注入された以降に開始し、且つキャ
ビティへの樹脂充填完了後１秒以内に終了させるように
したので、ヒケ、ソリ、デフォーム、バリ等の無い、品
質良好な樹脂成形品を得ることができる。 The runner groove extending from the vicinity of the gate toward the filling end of the cavity is filled with the molten resin almost simultaneously with the injection, and the pressing means is provided in the runner groove to detect the completion of filling. Even if there is no sensor to perform the pressing, the pressing can be performed before the filling is completed. Further, since the hot molten resin is continuously supplied to the runner groove from the start of filling to the completion of filling, uniform and balanced pressurization is possible.
Further, by performing the pressing by the pressing means from before the completion of the filling to after the completion of the filling, the same effect as when the injection pressure is increased is obtained, and efficient pressurization is possible. In particular, the present invention
The pressing operation by the pressure means is required to fill the resin cavity
Start after 75% of the fill has been injected and
Finish within 1 second after completion of filling resin to Viti
As it did, there is no sinker, sled, deform, burr, etc., product
A good quality resin molded product can be obtained.

【０００６】[0006]

【実施例】本発明の射出成形方法の実施例について添付
した図面に基づき説明する。図１は本発明の成形方法が
適用される金型構造の一例を示す縦断面図、図２、図３
は押圧手段による作用図であり、図２は加圧前、図３は
加圧後、図４は加圧する前の樹脂の形状を示す斜視図で
ある。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the injection molding method of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a longitudinal sectional view showing an example of a mold structure to which the molding method of the present invention is applied, and FIGS.
FIG. 2 is a perspective view showing the shape of the resin before pressing, FIG. 3 is a perspective view showing the shape of the resin before pressing, and FIG.

【０００７】図１に示すように、本発明の射出成形方法
の適用される射出成形機１は、上下一対の金型２、３
と、成形機本体の押出し機構４を備えており、両金型
２、３が型合せして形成するキャビティ５内にはゲート
６を介して溶融樹脂が注入される。そしてこの金型３の
ゲート６には、不図示の射出成形機に連なるスプル７が
連通している。As shown in FIG. 1, an injection molding machine 1 to which the injection molding method of the present invention is applied includes a pair of upper and lower molds 2 and 3.
And an extrusion mechanism 4 of the molding machine main body, and a molten resin is injected through a gate 6 into a cavity 5 formed by combining the two dies 2 and 3. A sprue 7 connected to an injection molding machine (not shown) communicates with the gate 6 of the mold 3.

【０００８】キャビティ５の形状は、例えば図４Ａに示
すような成形過程途中の樹脂Ｗの形状に合せた形状に形
成されており、薄肉平板部Ｗｏに対応する薄肉キャビテ
ィ部８（図１、図２）と、突出部Ｗｒに対応するランナ
溝部９（図１、図２）を備えている。The shape of the cavity 5 is formed, for example, in accordance with the shape of the resin W during the molding process as shown in FIG. 4A, and the thin cavity portion 8 corresponding to the thin flat plate portion Wo (FIG. 1, FIG. 2) and a runner groove 9 (FIGS. 1 and 2) corresponding to the protrusion Wr.

【０００９】そしてランナ溝部９は一端側が前記ゲート
６に直接連通し、他端側が溶融樹脂の充填末端側に向け
て延出している。The runner groove 9 has one end directly communicating with the gate 6 and the other end extending toward the filling end of the molten resin.

【００１０】又、例えば前記薄肉平板部Ｗｏの厚み、す
なわち薄肉キャビティ部８の厚みは約２ｍｍ程度であ
り、突出部Ｗｒの高さ、すなわちランナ溝部９の深さは
約２ｍｍから６ｍｍ程度、幅約１．５ｍｍ程度である。Further, for example, the thickness of the thin flat plate portion Wo, that is, the thickness of the thin cavity portion 8 is about 2 mm, the height of the projection Wr, that is, the depth of the runner groove 9 is about 2 mm to 6 mm, and the width is about 2 mm. It is about 1.5 mm.

【００１１】押出し機構４は固定板１１と、この固定板
１１と下型３間に取り付けられた押出板ガイド１２と、
この押出板ガイド１２によって案内されて上下動可能な
３枚の第１、第２、第３押出板１３、１４、１５を備え
ている。The extruding mechanism 4 includes a fixed plate 11, an extruded plate guide 12 mounted between the fixed plate 11 and the lower mold 3,
It is provided with three first, second, and third extruded plates 13, 14, and 15 that can be moved up and down while being guided by the extruded plate guide 12.

【００１２】そして第１押出板１３には、圧縮ロッド１
６を挿通せしめることの出来る挿通孔１３ａを設けると
ともに、リターンピン１７を固着せしめているが、その
細部について説明する。The first extruding plate 13 has the compression rod 1
An insertion hole 13a through which the insertion hole 6 can be inserted is provided, and the return pin 17 is fixed. The details will be described.

【００１３】図２に示すように、圧縮ロッド１６は第１
押出板１３に設けた挿通孔１３ａを摺動自在に貫き、そ
の上端には圧縮ブロック１８を取り付けている。そして
この圧縮ブロック１８は前記ランナ溝部９の形状に合せ
て形成され、該ランナ溝部９内に入り込んで中を摺動自
在に上下動出来るようにしている。As shown in FIG. 2, the compression rod 16 is
A through-hole 13a provided in the extruding plate 13 is slidably penetrated, and a compression block 18 is attached to an upper end thereof. The compression block 18 is formed in conformity with the shape of the runner groove 9 so as to enter the runner groove 9 and move up and down slidably therein.

【００１４】又、圧縮ロッド１６の下端側には大径部１
６ａが設けられており、一方、前記挿通孔１３ａにはこ
の大径部１６ａと略同径の大径孔部１３ｂが設けられて
いる。The lower end of the compression rod 16 has a large diameter portion 1.
The insertion hole 13a is provided with a large-diameter hole 13b having substantially the same diameter as the large-diameter portion 16a.

【００１５】そして大径孔部１３ｂの上下方向の深さ
は、大径部１６ａの高さ方向の厚みより大きく形成され
ており、このため大径部１６ａの下面が第１押出板１３
の下面と面一になった際、大径孔部１３ｂ内に上下間隔
ｓの遊動空間部が形成されるようにしている。そしてこ
の遊動空間部の間隔ｓは、概略、図４に示す突出部Ｗｒ
の高さ、すなわちランナ溝部９の深さに一致させてい
る。The vertical depth of the large-diameter hole 13b is formed to be greater than the thickness of the large-diameter portion 16a in the height direction.
When it is flush with the lower surface, a floating space with a vertical interval s is formed in the large-diameter hole 13b. The interval s between the floating spaces is substantially equal to the protrusion Wr shown in FIG.
, That is, the depth of the runner groove 9.

【００１６】一方、リターンピン１７は、その下端が第
１押出板１３に固着されており、下型３と第１押出板１
３の間の中間部にリターンスプリング２０を巻装せしめ
ている。そして後述するように、このリターンスプリン
グ２０は押出板１３、１４復帰用のものである。On the other hand, the lower end of the return pin 17 is fixed to the first extrusion plate 13 and the lower die 3 and the first extrusion plate 1 are fixed.
A return spring 20 is wound around an intermediate portion between the two. As described later, the return spring 20 is for returning the push plates 13 and 14.

【００１７】又、前記圧縮ブロック１８には、圧縮ブロ
ック引戻しバー２１を設けている。すなわちこの圧縮ブ
ロック引戻しバー２１は、圧縮ブロック１８の復帰用の
ものであり、下型３に対して摺動自在とされるとともに
下端延出部が下型３外に突出して、この突出部に引戻し
スプリング２２を設けている。The compression block 18 is provided with a compression block pullback bar 21. That is, the compression block retraction bar 21 is for returning the compression block 18, is slidable with respect to the lower mold 3, and has a lower end extension projecting out of the lower mold 3 so that the projection 21 A retraction spring 22 is provided.

【００１８】ところで第２押出板１４は、以上のような
第１押出板１３の下方に設けられているが、第１押出板
１３の挿通孔１３ａの位置に対応して貫通孔１４ａを備
えている。そしてこの貫通孔１４ａ内を、以下に述べる
第３押出板１５の押出しブロック１５ａが挿通してい
る。The second extruding plate 14 is provided below the first extruding plate 13 as described above. The second extruding plate 14 has a through hole 14a corresponding to the position of the insertion hole 13a of the first extruding plate 13. I have. An extruding block 15a of the third extruding plate 15 described below is inserted through the through hole 14a.

【００１９】第３押出板１５は最下方の押出板であり、
上記のように上面に押出しブロック１５ａを備え、この
押出しブロック１５ａによって前記圧縮ロッド１６の大
径部１６ａ下面に当接可能にしている。すなわち、この
押出しブロック１５ａの高さは第２押出板１４の板厚よ
り大きくし、この押出しブロック１５ａの高さと第２押
出板１４の板厚の差は、略々第１押出板１３の大径孔部
１３ｂの遊動空間部の間隔ｓに一致させている。The third extruded plate 15 is the lowermost extruded plate,
As described above, the extrusion block 15a is provided on the upper surface, and the extrusion block 15a enables the compression rod 16 to contact the lower surface of the large diameter portion 16a. That is, the height of the extrusion block 15a is larger than the thickness of the second extrusion plate 14, and the difference between the height of the extrusion block 15a and the thickness of the second extrusion plate 14 is substantially the same as the thickness of the first extrusion plate 13. The gap s is set to be equal to the interval s between the floating space portions of the radial hole portion 13b.

【００２０】そして固定板１１には図１に示すようなノ
ックアウト孔１１ａを設けており、このノックアウト孔
１１ａを通して下方からエジェクタロッド２３が昇降動
するようにしている。The fixing plate 11 is provided with a knockout hole 11a as shown in FIG. 1, and the ejector rod 23 moves up and down from below through the knockout hole 11a.

【００２１】以上のような射出成形機１において、不図
示の射出ノズルからゲート６を介してキャビティ５内に
溶融樹脂を射出すると、溶融樹脂はランナ溝部９を通し
て迅速にキャビティ部８内に充填され、しかもランナ溝
部９内には熱い溶融樹脂が充填完了まで供給され続け
る。そして例えば油圧駆動によってエジェクタロッド２
３を所定ストローク前進させ、第３押出板１５を例えば
遊動空間部の間隔ｓ程度のストローク分押し込むことに
よって、図３に示すように、第１押出板１３の位置を元
の位置に戻してキャビティ内を加圧し樹脂を硬化させる
訳であるが、この押圧動作について図５に基づき説明す
る。In the above-described injection molding machine 1, when molten resin is injected into the cavity 5 from the injection nozzle (not shown) via the gate 6, the molten resin is quickly filled into the cavity 8 through the runner groove 9. In addition, the hot molten resin is continuously supplied into the runner groove 9 until the filling is completed. The ejector rod 2 is driven by, for example, a hydraulic drive.
3 is advanced by a predetermined stroke, and the third extruding plate 15 is pushed in by a stroke of, for example, the interval s of the idle space portion, thereby returning the position of the first extruding plate 13 to the original position, as shown in FIG. The inside is pressurized to cure the resin. This pressing operation will be described with reference to FIG.

【００２２】尚、図５は加圧動作の開始、終了を射出動
作のどの位置から行うのが適切かについての実験データ
を纏めたものであり、上欄の「射出動作」の欄は射出完
了前は充填量（全体に対する充填割合％）で示し、射出
完了後は時間（秒）で示している。又、下欄の「ランナ
潰し量（ｍｍ）」と「外観品質」は射出動作の各時点か
ら加圧動作を開始した時の各状態であり、「ランナ潰し
量（ｍｍ）」は圧縮ブロック１８の上昇ストロークを示
し、「外観品質」は硬化後の成形状態を示す。FIG. 5 is a table summarizing experimental data as to where the start and end of the pressurizing operation should be performed in the injection operation. Before the injection, it is indicated by the filling amount (filling ratio% with respect to the whole), and after the injection is completed, it is indicated by the time (second). The “runner crush amount (mm)” and “appearance quality” in the lower column are the respective states when the pressurizing operation is started from each point of the injection operation, and the “runner crush amount (mm)” is the compression block 18. And the “appearance quality” indicates the molded state after curing.

【００２３】これによると、例えばランナ溝部９の深さ
が６ｍｍの場合、射出完了前のいかなる時点でも、又射
出完了後でも２秒以内であればランナ潰しは可能である
が、射出完了後３秒を越えると最早完全に潰すことが出
来なくなることが判る。この際、当然のことながらラン
ナ潰しのタイミングが早いと樹脂の流動支援効果が薄
れ、ランナ潰しのタイミングが遅いと高い潰し力が必要
とされる。According to this, for example, when the depth of the runner groove 9 is 6 mm, the runner can be crushed at any time before the injection is completed or within 2 seconds after the injection is completed. It turns out that it is no longer possible to completely crush when the time exceeds seconds. In this case, if the timing of crushing the runner is early, the effect of supporting the flow of the resin is reduced, and if the timing of crushing the runner is late, a high crushing force is required.

【００２４】そして例えば充填量５０％の時点から加圧
動作を開始すれば、ヒケ、マーク、バリ等の不具合が発
生するが、充填量７５％から開始すれば充填、ヒケ、ソ
リ、デフォーム、マーク、バリ等の外観品質は良好に保
てる。又、充填完了後１秒以内であっても外観品質を良
好に保てるが、２秒以上になるとソリ等の不具合が発生
する。If, for example, the pressurizing operation is started at the time of the filling amount of 50%, problems such as sink marks, marks and burrs will occur. Good appearance quality such as marks and burrs can be maintained. In addition, the appearance quality can be kept good even within 1 second after the completion of filling, but when the time is 2 seconds or more, defects such as warping occur.

【００２５】従ってこの実験の結果、ランナ溝部９への
加圧は溶融樹脂の７５％の充填から射出完了後１秒以内
が有効であることが判った。そこで、本発明では、射出
完了前の充填量７５％の時点から以降で射出完了前に加
圧を開始し、射出完了後１秒程度までに加圧を終了させ
るようにする。 Therefore, as a result of this experiment, it was found that the pressurization of the runner groove 9 was effective within 75 seconds from the filling of the molten resin within 1 second after the completion of the injection. Therefore, in the present invention, the pressurization is started from the point of 75% of the filling amount before the injection is completed and before the injection is completed, and the pressurization is completed by about 1 second after the injection is completed.
So that

【００２６】そしてかかる加圧動作によって加圧された
樹脂が凝固が完了すると型開きして成形品を取り出す。
つまり、エジェクタロッド２３を更に前進させ、第１押
出板１３を上昇させて圧縮ロッド１６、圧縮ブロック１
８を前進させて成形品を突出す。When the resin pressurized by the pressurizing operation is completely solidified, the mold is opened and the molded product is taken out.
That is, the ejector rod 23 is further advanced, and the first extruding plate 13 is raised, so that the compression rod 16, the compression block 1
8 is advanced to protrude the molded product.

【００２７】尚、ゲート６から充填末端側に延出するラ
ンナ溝部９は、例えば製品の大きさ、形状等によって複
数設けるようにしてもよく、又、この複数のランナ溝部
９を交差させて図４Ｂに示すような交差状の突出部Ｗｒ
を形成するようにしてもよい。A plurality of runner grooves 9 extending from the gate 6 to the filling end may be provided, for example, depending on the size, shape, etc. of the product. A cross-shaped projection Wr as shown in FIG. 4B
May be formed.

【００２８】[0028]

【発明の効果】以上のように、本発明の射出成形方法は
金型のゲート近傍からキャビティの充填末端側に向けて
延出するランナ溝部の加圧手段を設けるようにしたの
で、射出された樹脂はほぼ同時にランナ溝部に満たさ
れ、加圧部に充填されたか否かを検知するセンサ等を設
ける必要がない。又、このランナ溝部には充填完了まで
熱い溶融樹脂が供給され続けることから、バランスの良
い均一な加圧が可能である。又、加圧動作の開始を充填
完了前からとし、加圧効果のなくなる充填完了後に終了
することで射出圧の補完効果があり、射出圧をさほど高
めなくても効率良く加圧出来る。そして製品全体が均一
に加圧されることによって局部的な応力集中によるそ
り、変形等の不具合、各種マーク不良、バリ不良といっ
た不具合が防止出来る。特に本発明は、押圧手段による
押圧動作を、樹脂のキャビティへの必要充填量の７５％
が射出注入された以降に開始し、且つキャビティへの樹
脂充填完了後１秒以内に終了させるようにしたので、ヒ
ケ、ソリ、デフォーム、バリ等の無い、品質良好な樹脂
成形品を得ることができる。 As described above, according to the injection molding method of the present invention, the pressurizing means for the runner groove extending from the vicinity of the gate of the mold toward the filling end of the cavity is provided. The resin is almost simultaneously filled in the runner groove, and there is no need to provide a sensor or the like for detecting whether or not the resin is filled in the pressurized portion. Further, since the hot molten resin is continuously supplied to the runner groove portion until the filling is completed, a well-balanced and uniform pressurization is possible. In addition, the pressurizing operation is started before the completion of the filling and is completed after the completion of the filling in which the pressurizing effect is lost, so that there is an effect of complementing the injection pressure. By uniformly pressing the entire product, defects such as warpage and deformation due to local stress concentration, defects of various marks, and defects of burrs can be prevented. In particular, the invention is based on the pressing means
75% of the required filling amount of resin into the cavity
Started after injection of the
Since the operation is completed within 1 second after the completion of filling with grease,
Good quality resin without burrs, warpage, deformation, burrs, etc.
A molded article can be obtained.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明の成形方法が適用される金型構造の一例
を示す縦断面図FIG. 1 is a longitudinal sectional view showing an example of a mold structure to which a molding method of the present invention is applied.

【図２】押圧手段による作用図であり、加圧前の状態FIG. 2 is an operation diagram of a pressing unit, showing a state before pressurization.

【図３】押圧手段による作用図であり、加圧後の状態FIG. 3 is an operation diagram of a pressing unit, showing a state after pressurization.

【図４】加圧する前の樹脂の形状を示す斜視図でＡはラ
ンナ溝部を１本としたもの、Ｂはランナ溝部を複数とし
たものFIG. 4 is a perspective view showing a shape of a resin before pressing, in which A is a single runner groove, and B is a plurality of runner grooves.

【図５】加圧動作の開始と射出動作との関係についての
実験データFIG. 5 shows experimental data on the relationship between the start of the pressurizing operation and the injection operation.

【符号の説明】[Explanation of symbols]

５ キャビティ ６ ゲート ９ ランナ溝部 5 Cavity 6 Gate 9 Runner groove

Claims (1)

(57)【特許請求の範囲】(57) [Claims] 【請求項１】 金型のキャビティ内に充填した溶融樹脂
を押圧手段によって加圧し成形するようにした射出成形
法において、 前記押圧手段は、金型のゲート近傍からキャビティの充
填末端側に向けてランナ溝部として延出する樹脂溜め部
に設けられ、この押圧手段による押圧動作は、樹脂のキ
ャビティへの必要充填量の７５％が射出注入された以降
に開始し、 且つキャビティへの 樹脂充填完了後１秒以内に終了させ
るようにした、 ことを特徴とする射出成形方法。In an injection molding method in which a molten resin filled in a cavity of a mold is pressed and molded by a pressing means, the pressing means moves from a vicinity of a gate of the mold to a filling end side of the cavity. provided in the resin reservoir extending as runner groove portion, the pressing operation by the pressing means, the resin key
After injection of 75% of the required filling amount into the cavity
Start the causes and is completed within 1 second after resin filling completion into the cavity
Was so that, injection molding method, characterized in that.
JP4273823A 1991-11-22 1992-09-17 Injection molding method Expired - Fee Related JP2661656B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP4273823A JP2661656B2 (en) 1991-11-22 1992-09-17 Injection molding method

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP3-104229 1991-11-22
JP10422991 1991-11-22
JP4273823A JP2661656B2 (en) 1991-11-22 1992-09-17 Injection molding method

Publications (2)

Publication Number Publication Date
JPH05200801A JPH05200801A (en) 1993-08-10
JP2661656B2 true JP2661656B2 (en) 1997-10-08

Family

ID=26444743

Family Applications (1)

Application Number Title Priority Date Filing Date
JP4273823A Expired - Fee Related JP2661656B2 (en) 1991-11-22 1992-09-17 Injection molding method

Country Status (1)

Country Link
JP (1) JP2661656B2 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4368799B2 (en) * 2002-09-03 2009-11-18 ポリプラスチックス株式会社 Composite injection molding method and mold
JP2010094930A (en) * 2008-10-20 2010-04-30 Narumi Gokin Seisakusho:Kk Injection molding method of handle for automobile use, and handle for automobile use

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5657818U (en) * 1979-10-12 1981-05-19
JP3253991B2 (en) * 1991-10-24 2002-02-04 旭化成株式会社 Injection molding method

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Publication number Publication date
JPH05200801A (en) 1993-08-10

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