JPH0929783A - Injection mold - Google Patents
Injection moldInfo
- Publication number
- JPH0929783A JPH0929783A JP20510695A JP20510695A JPH0929783A JP H0929783 A JPH0929783 A JP H0929783A JP 20510695 A JP20510695 A JP 20510695A JP 20510695 A JP20510695 A JP 20510695A JP H0929783 A JPH0929783 A JP H0929783A
- Authority
- JP
- Japan
- Prior art keywords
- gate
- pin gate
- pin
- mold
- 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.)
- Pending
Links
- 238000002347 injection Methods 0.000 title abstract description 9
- 239000007924 injection Substances 0.000 title abstract description 9
- 229920005989 resin Polymers 0.000 claims abstract description 25
- 239000011347 resin Substances 0.000 claims abstract description 25
- 238000011144 upstream manufacturing Methods 0.000 claims abstract description 7
- 238000001746 injection moulding Methods 0.000 claims description 25
- 229920003002 synthetic resin Polymers 0.000 claims description 4
- 239000000057 synthetic resin Substances 0.000 claims description 4
- 238000009413 insulation Methods 0.000 abstract description 3
- 239000000243 solution Substances 0.000 abstract 1
- 238000000465 moulding Methods 0.000 description 13
- 238000001816 cooling Methods 0.000 description 5
- 229920000122 acrylonitrile butadiene styrene Polymers 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 229920005497 Acrypet® Polymers 0.000 description 2
- 229920000297 Rayon Polymers 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000003566 sealing material Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000002040 relaxant effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000000565 sealant Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
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
- B29C45/26—Moulds
- B29C45/27—Sprue channels ; Runner channels or runner nozzles
- B29C45/2701—Details not specific to hot or cold runner channels
- B29C45/2708—Gates
- B29C45/2711—Gate inserts
-
- 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
- B29C45/26—Moulds
- B29C45/27—Sprue channels ; Runner channels or runner nozzles
-
- 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
- B29C45/26—Moulds
- B29C45/27—Sprue channels ; Runner channels or runner nozzles
- B29C2045/2766—Heat insulation between nozzle and mould
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、スプルーもしくは
ランナー等の樹脂流路と成形品用キャビティとを接続す
るピンゲート（ピンポイントゲート）を有する合成樹脂
射出成形用金型に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin injection molding die having a pin gate (pin point gate) for connecting a resin passage such as a sprue or runner to a cavity for a molded product.
【０００２】[0002]
【従来の技術】樹脂成形品の成形方法のうち、広く用い
られている射出成形方法は、熱可塑性樹脂の、加熱溶融
と冷却固化の性質を利用して溶融樹脂を金型キャビティ
内に圧入し、冷却後型より取り出す方法である。この射
出成形に広く用いられる上記ピンゲートは、断面積を極
めて小さくしたもので、主として３枚構造の金型に使用
されている。このピンゲートを用いた射出成形用金型で
は、成形品と、スプルーもしくはランナーとがゲートで
切断されて、金型から取り出されるので、ゲート切断の
手間が省ける利点がある。2. Description of the Related Art Of the molding methods for resin molded products, the widely used injection molding method is to use the properties of thermoplastic resin to heat and melt and to cool and solidify the molten resin to press it into the mold cavity. The method is to take out from the mold after cooling. The pin gate widely used in this injection molding has an extremely small cross-sectional area and is mainly used in a mold having a three-piece structure. In the injection mold using the pin gate, the molded product and the sprue or runner are cut at the gate and taken out from the mold, which has the advantage of saving the labor of cutting the gate.
【０００３】図３は従来のピンゲートの断面を示す図で
あり、ゲート径ｄは０．８〜１．８ｍｍφ、ランド長Ｌ
は１．０〜２．０ｍｍに設計される場合が多い。また、
一般に成形品表面でピンゲートが切断されるように、ラ
ンド部には１〜１５°のテーパがつけられている。FIG. 3 is a view showing a cross section of a conventional pin gate. The gate diameter d is 0.8 to 1.8 mmφ and the land length L is L.
Is often designed to be 1.0 to 2.0 mm. Also,
Generally, the land portion has a taper of 1 to 15 so that the pin gate is cut on the surface of the molded product.
【０００４】[0004]
【発明が解決しようとする課題】ピンゲートは、ゲート
切断の手間が省ける反面、製品にゲート跡が残ることは
避け難い。ゲート跡は図４のように射出成形品から突起
状に突出している。ゲート跡径ｄはピンゲート径に一致
するが、ゲート跡高さｈはゲート径および射出成形条件
により異ってくる。実験によれば、ゲート径が大きくな
るとゲート跡高さもこれに比例して大きくなる傾向を示
し、ゲート跡高さはほぼゲート径と一致したものとな
る。ゲート跡が突出する原因は、ゲート部での分子配向
にあると考えられる。つまり、ピンゲート部は溶融樹脂
の流路が絞られて狭くなるため、通過速度が大きく、強
い分子配向を受ける。従来の射出成形では、流動方向と
平行な分子配向が冷却により凍結してしまい、成形品と
スプルーを切り離した後のピンゲート跡が前記のように
突起状に突出する。The pin gate saves the labor of cutting the gate, but it is unavoidable that a gate mark is left on the product. The gate traces protrude from the injection-molded product in a protruding shape as shown in FIG. The gate trace diameter d matches the pin gate diameter, but the gate trace height h differs depending on the gate diameter and injection molding conditions. According to the experiment, when the gate diameter increases, the gate trace height also tends to increase in proportion to this, and the gate trace height almost coincides with the gate diameter. It is considered that the cause of the gate trace protruding is the molecular orientation in the gate portion. That is, in the pin gate portion, the flow path of the molten resin is narrowed and narrowed, so that the passage speed is high and the molecular orientation is strong. In the conventional injection molding, the molecular orientation parallel to the flow direction is frozen by cooling, and the pin gate traces after separating the molded product and the sprue are projected like the protrusions as described above.
【０００５】本発明者等は、この分子配向を緩和するこ
とでゲート跡の突起を発生させないようにすることがで
きると考えて、鋭意研究の結果本発明に到達した。The present inventors have arrived at the present invention as a result of earnest research, considering that it is possible to prevent the projection of a gate mark from being generated by relaxing this molecular orientation.
【０００６】この突起は、一種の外観不良をもたらすも
ので、製品仕様を満足できない場合は、後仕上げを行わ
なければならない。また、ゲート跡が成形品表面から突
出してはいけない場合は、ピンゲートを成形品の表面か
ら少し沈めて設けることもあり、このため、デザイン、
設計上の制約を受けていた。また、ピンゲートの径を小
さくすれば、ゲート跡高さを小さくすることができる
が、この場合は圧力損失が大きくなり、ショートショッ
トなどの成形不良が生じ、所望の成形品を得ることがで
きない。このため、ＡＢＳ樹脂の場合は、ピンゲートの
径を通常１．０ｍｍφ以上とせざるを得なかった。These protrusions cause a kind of appearance defect, and if the product specifications cannot be satisfied, post-finishing must be performed. In addition, if the gate trace should not protrude from the surface of the molded product, the pin gate may be set slightly below the surface of the molded product.
It was restricted by design. Further, if the diameter of the pin gate is made small, the height of the gate trace can be made small, but in this case, the pressure loss becomes large and molding defects such as short shots occur, so that the desired molded product cannot be obtained. For this reason, in the case of ABS resin, the diameter of the pin gate must be usually 1.0 mmφ or more.
【０００７】本発明は、これらの状況に鑑みなされたも
ので、ピンゲートの表面構造に変更を加えることなく、
ピンゲート跡高さを低減させる射出成形用金型を提供す
ることを目的とする。The present invention has been made in view of these circumstances, and it is possible to improve the surface structure of the pin gate without changing it.
An object of the present invention is to provide an injection molding die that reduces the height of the pin gate trace.
【０００８】[0008]
【課題を解決するための手段】上記目的を達成するため
に、本発明に係る射出成形用金型は、ピンゲート及びそ
の上流に接続された樹脂流路を有する合成樹脂の射出成
形用金型において、上記樹脂流路の上記ピンゲートに近
い部位を筒状囲壁により構成し、この筒状囲壁の外側空
間部に筒状断熱層を配設してなることを特徴とするもの
である。In order to achieve the above-mentioned object, an injection molding die according to the present invention is a synthetic resin injection molding die having a pin gate and a resin flow path connected upstream thereof. A portion of the resin flow path near the pin gate is configured by a tubular surrounding wall, and a tubular heat insulating layer is disposed in an outer space portion of the tubular surrounding wall.
【０００９】本発明における射出成形用金型は、樹脂流
路のピンゲートに近い部位を筒状囲壁により構成し、こ
の筒状囲壁の外側空間部に筒状断熱層を配設したことに
より、定常状態の射出成形においてゲート部が高温に保
たれる。このため、ゲート部で生じ易い分子配向が緩和
されるので、ゲート切り離し後のゲート跡の突起高さが
減少する。さらに、ジェッティング、ショートショット
等の成形不良がなくなる。In the injection molding die according to the present invention, a portion of the resin flow path close to the pin gate is constituted by a tubular surrounding wall, and a tubular heat insulating layer is provided in an outer space portion of the tubular surrounding wall, so that a steady state is obtained. In the injection molding of the state, the gate portion is kept at a high temperature. For this reason, the molecular orientation that tends to occur at the gate portion is relaxed, and the height of the protrusion of the gate trace after the gate separation is reduced. Furthermore, molding defects such as jetting and short shots are eliminated.
【００１０】[0010]
【発明の実施の形態】以下本発明の実施例を図面に基づ
き説明する。図１は本発明の第１実施例の金型の断面図
である。図において７は射出成形用金型、１は固定側金
型、１２は固定側金型１に型合せされるランナプレー
ト、２はランナプレート１２に型合せされる可動側金型
で、この可動側金型２は図示しない流体圧シリンダ装置
に直結されており、流体圧により図面上では上下方向に
可動される。３は製品のキャビティで、ランナプレート
１２に可動側金型２を突き合わせることにより形成され
ている。４はピンゲート、５はピンゲート４の上流に接
続された樹脂流路としての第２スプルー、９はこの第２
スプルーの上流に接続されたランナで、上記４，５，９
は段付円筒状のピンゲートブッシュ６に彫り込まれてお
り、ランナプレート１２に彫り込まれた段付円筒状の嵌
合穴に上記ピンゲートブッシュ６を嵌合させることによ
り位置決めされる。上記ランナ９は固定側金型１にラン
ナプレート１２を型合せすることにより形成され、ラン
ナ９の上流に接続される第１スプルー１０が固定側金型
１に彫り込まれている。１１はロケートリングで図示し
ないノズルの位置決めをするはたらきをする。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a mold according to a first embodiment of the present invention. In the figure, 7 is an injection molding die, 1 is a fixed side die, 12 is a runner plate that is fitted to the fixed side die 1, and 2 is a movable side die that is fitted to the runner plate 12. The side mold 2 is directly connected to a fluid pressure cylinder device (not shown) and is movable in the vertical direction in the drawing by fluid pressure. Reference numeral 3 denotes a product cavity, which is formed by abutting the movable die 2 on the runner plate 12. 4 is a pin gate, 5 is a second sprue as a resin flow path connected upstream of the pin gate 4, and 9 is this second sprue.
The runner connected upstream of the sprue
Is engraved on the stepped cylindrical pin gate bush 6 and is positioned by fitting the pin gate bush 6 into the stepped cylindrical fitting hole engraved on the runner plate 12. The runner 9 is formed by fitting the runner plate 12 to the fixed-side mold 1, and the first sprue 10 connected upstream of the runner 9 is engraved in the fixed-side mold 1. Locating ring 11 serves to position a nozzle (not shown).
【００１１】本発明の要旨は、樹脂流路としての第２ス
プルー５のピンゲート４に近い部位の外周に筒状断熱層
８を設けたことにある。この実施例では第２スプルー５
のピンゲートに近い部位に旋削加工により筒状囲壁６ａ
を形成し、同時に、筒状の外側空間部８ａを形成するも
のであり、この外側空間部８ａが筒状断熱層８となるも
のである。この外側空間部８ａに存在する空気は鋼材に
比べて約１０００倍の断熱性を有する。The gist of the present invention is to provide a cylindrical heat insulating layer 8 on the outer periphery of a portion of the second sprue 5 as a resin flow path near the pin gate 4. In this embodiment, the second sprue 5
Cylindrical surrounding wall 6a by turning on the part close to the pin gate of
And the tubular outer space portion 8a is formed at the same time. The outer space portion 8a serves as the tubular heat insulating layer 8. The air present in the outer space 8a has a heat insulating property which is about 1000 times that of steel.
【００１２】本実施例で使用したピンゲート４は、直
径：１．２ｍｍφ、ランド長：１．５ｍｍ、テーパ：片
側５°であり、第２スプルー５は、最小径：４ｍｍ、テ
ーパ：片側２°、全長：５５ｍｍであり、ピンゲートブ
ッシュ６の嵌合部外径は１５ｍｍφである。断熱層の大
きさは、定常状態におけるピンゲート４の温度とのバラ
ンスで決定される。本実施例では、深さ３〜４．５ｍ
ｍ、長さ４０ｍｍの円筒状の断熱層を形成した。The pin gate 4 used in this embodiment has a diameter of 1.2 mmφ, a land length of 1.5 mm and a taper of 5 ° on one side. The second sprue 5 has a minimum diameter of 4 mm and a taper of 2 ° on one side. The total length is 55 mm, and the outer diameter of the fitting portion of the pin gate bush 6 is 15 mmφ. The size of the heat insulating layer is determined by the balance with the temperature of the pin gate 4 in the steady state. In this embodiment, the depth is 3 to 4.5 m.
A cylindrical heat insulating layer having a length of m and a length of 40 mm was formed.
【００１３】本発明の目的を達成するためには、ピンゲ
ート４の外側にも絶縁層を形成することが好ましいが、
ピンゲート外側部は製品のキャビティ３表面に近接して
いるので射出圧に充分耐えられる数ミリの厚さをキャビ
ティ壁６ｂに残しておく必要があるためピンゲート４の
外側位置まで筒状断熱層としての筒状の外側空間部８を
形成するには限度がある。To achieve the object of the present invention, it is preferable to form an insulating layer also on the outside of the pin gate 4.
Since the outer portion of the pin gate is close to the surface of the cavity 3 of the product, it is necessary to leave a thickness of several millimeters sufficient to withstand the injection pressure in the cavity wall 6b. There is a limit to the formation of the cylindrical outer space portion 8.
【００１４】上記装置にＡＢＳ樹脂である三菱レイヨン
（株）製の登録商標「ダイヤペット」ＡＢＳ３００１を
供給して、シリンダ温度２２０℃、金型温度２７℃（水
冷）で射出成形を行った場合、ノズルより射出された溶
解樹脂は第１スプルー１０、ランナー９、第２スプルー
５を順次経由し、ピンゲート４を介してキャビティ３に
注入される。成形品取出し直後のピンゲート部の金型表
面温度は８５℃に上昇して、連続成形作業中安定した。
「ダイヤペット」ＡＢＳ３００１の熱変形温度は９１℃
であるからピンゲート部の金型表面温度は熱変形温度−
６℃に相当する。ゲートカット後のピンゲート跡高さは
０．１ｍｍ以下であり、成形品としての外観は良好であ
った。When the ABS resin, a registered trademark "Diapet" manufactured by Mitsubishi Rayon Co., Ltd., which is an ABS resin, is supplied to the above apparatus and injection molding is performed at a cylinder temperature of 220 ° C and a mold temperature of 27 ° C (water cooling), The molten resin injected from the nozzle sequentially passes through the first sprue 10, the runner 9, and the second sprue 5, and is injected into the cavity 3 through the pin gate 4. Immediately after taking out the molded product, the mold surface temperature of the pin gate portion rose to 85 ° C. and became stable during the continuous molding operation.
The heat distortion temperature of "Diapet" ABS3001 is 91 ℃
Therefore, the mold surface temperature of the pin gate part is the thermal deformation temperature −
Equivalent to 6 ° C. The height of the pin gate trace after the gate was cut was 0.1 mm or less, and the appearance as a molded product was good.
【００１５】比較のために、筒状断熱層を備えない同一
形状の樹脂流路およびキャビティを有する金型を用いて
同一原料を供給し、同一条件下で射出成形を行ったとこ
ろ、成形品取り出し直後のピンゲート部の金型表面温度
は５５℃に上昇して、連続成形作業中安定したが、ゲー
トカット後のピンゲート跡高さは０．５〜１．５ｍｍで
あり、成形品としての外観は不良であった。For comparison, the same raw material was supplied using a mold having a resin flow path and a cavity of the same shape without a tubular heat insulating layer, and injection molding was performed under the same conditions. Immediately after, the mold surface temperature of the pin gate portion rose to 55 ° C and became stable during the continuous molding operation, but the pin gate trace height after gate cutting was 0.5 to 1.5 mm, and the appearance as a molded product was It was bad.
【００１６】また、上記装置にアクリル樹脂としての三
菱レイヨン（株）製の登録商標「アクリペット」ＶＨを
供給して、シリンダ温度２５０℃、金型温度２７℃（水
冷）で射出成形を行った場合、ノズルより射出された溶
融樹脂は第１スプルー１０、ランナ９、第２スプルー５
を順次経由し、ピンゲート４を介してキャビティ３に注
入される。成形品取出し直後のピンゲート部の金型表面
温度は９５℃に上昇して、連続成形作業中安定した。
「アクリペット」ＶＨの熱変形温度は１００℃であるか
らピンゲート部の金型表面温度は、熱変形温度−５℃に
相当する。ゲートカット後のピンゲート跡高さは０．１
ｍｍ以下であり、成形品としての外観は良好であった。Further, a registered trademark "Acrypet" VH manufactured by Mitsubishi Rayon Co., Ltd. as an acrylic resin was supplied to the above apparatus, and injection molding was carried out at a cylinder temperature of 250 ° C. and a mold temperature of 27 ° C. (water cooling). In this case, the molten resin injected from the nozzle is the first sprue 10, the runner 9 and the second sprue 5.
Through the pin gate 4 and then into the cavity 3. Immediately after the molded product was taken out, the mold surface temperature of the pin gate portion rose to 95 ° C. and became stable during the continuous molding operation.
Since the heat deformation temperature of "Acrypet" VH is 100 ° C, the mold surface temperature of the pin gate portion corresponds to the heat deformation temperature of -5 ° C. Height of pin gate trace after gate cut is 0.1
It was less than or equal to mm, and the appearance as a molded product was good.
【００１７】比較のために、筒状断熱層を備えない同一
形状の樹脂流路およびキャビティを有する金型を用いて
同一原料を供給し、同一条件下で射出成形を行ったとこ
ろ、成形品取り出し直後のピンゲート部の金型表面温度
は５６℃に上昇して連続成形作業中安定したが、ゲート
カット後のピンゲート跡高さは０．８〜１．６ｍｍであ
り、成形品としての外観は不良であった。For comparison, the same raw material was supplied using a mold having a resin flow path and a cavity of the same shape without a cylindrical heat insulating layer, and injection molding was performed under the same conditions. Immediately after, the mold surface temperature of the pin gate portion rose to 56 ° C and became stable during the continuous molding operation, but the pin gate mark height after gate cutting was 0.8 to 1.6 mm, and the appearance as a molded product was poor. Met.
【００１８】射出成形では溶融樹脂を金型に充填して、
冷却固化させることになるが、本発明によれば、ピンゲ
ート近傍すなわち第２スプルーのピンゲートに近い部位
を筒状囲壁により構成し、この筒状囲壁の外側空間に筒
状断熱層を設けることにより、ピンゲート部分の冷却固
化が成形品より遅れる現象が生じる。したがって、ピン
ゲートでの分子配向が緩和される。In injection molding, a molten resin is filled in a mold,
According to the present invention, the portion near the pin gate, that is, the portion close to the pin gate of the second sprue is constituted by the tubular surrounding wall, and the tubular heat insulating layer is provided in the outer space of the tubular surrounding wall. A phenomenon occurs in which the cooling and solidification of the pin gate portion is delayed compared to the molded product. Therefore, the molecular orientation at the pin gate is relaxed.
【００１９】断熱層を形成していない従来の射出成形で
は、成形品取り出し直後の金型表面温度は、ピンゲート
部のみならずキャビティ全体にわたって射出成形作業中
に５〜３０℃上昇する。この温度上昇はシリンダ温度、
金型温度および成形サイクルなどに依存する。一方、本
発明による断熱層を設けた場合は、さらに大きな温度上
昇がピンゲート先端部のみに現れる。このため、ピンゲ
ート通過時の樹脂の流動性が良くなり、成形性が向上す
るという利点も付加される。In the conventional injection molding in which the heat insulating layer is not formed, the mold surface temperature immediately after taking out the molded product rises by 5 to 30 ° C. not only in the pin gate portion but also in the entire cavity during the injection molding operation. This temperature rise is due to the cylinder temperature,
Depends on mold temperature and molding cycle. On the other hand, when the heat insulating layer according to the present invention is provided, a further large temperature rise appears only at the tip of the pin gate. For this reason, the fluidity of the resin when passing through the pin gate is improved, and the advantage that the moldability is improved is added.
【００２０】一般に、シリンダ温度、金型温度を高くす
れば成形性、外観共に向上するが、成形サイクルが長く
なるという問題点がある。しかし、本発明の射出成形用
金型を用いれば、成形サイクルに影響を与えずに成形
性、外観が向上するから生産性を低下させることはな
い。Generally, when the cylinder temperature and the mold temperature are raised, both the moldability and the appearance are improved, but there is a problem that the molding cycle becomes long. However, when the injection molding die of the present invention is used, the moldability and appearance are improved without affecting the molding cycle, and therefore the productivity is not reduced.
【００２１】本発明による他の実施例を図２に示す。前
記第１の実施例ではピンゲート４はピンゲートブッシュ
６に形成されており、ランナプレート１２の嵌合穴と嵌
合させていたが、ピンゲートブッシュ６を使用せず、ラ
ンナプレート１２にピンゲート４および第２スプルー５
を直接彫り込んでもよい。この場合、断熱層８はランナ
プレート１２に筒状に直接彫り込んで形成することにな
るが、その際射出圧に充分耐えられるように第２スプル
ー外周に厚さ数ミリの筒状囲壁６ａを残し、またキャビ
ティ３上に厚さ数ミリのキャビティ壁６ｂを残すことが
好ましい。さらに強度保持上およびランナ９を形成する
ために、封止材１３で筒状断熱層８（外側空間部８ａ）
を残して加工孔を塞ぐ必要がある。封止材１３はランナ
プレート１２と同材質とするのが好ましい。Another embodiment according to the present invention is shown in FIG. In the first embodiment, the pin gate 4 is formed in the pin gate bush 6 and is fitted in the fitting hole of the runner plate 12, but the pin gate bush 6 is not used, and the pin gate 4 and the pin gate 4 are formed in the runner plate 12. 2 sprue 5
May be directly engraved. In this case, the heat insulating layer 8 is formed by directly engraving the runner plate 12 in a cylindrical shape. At that time, a cylindrical surrounding wall 6a having a thickness of several millimeters is left on the outer periphery of the second sprue so as to sufficiently withstand the injection pressure. It is preferable to leave the cavity wall 6b having a thickness of several millimeters on the cavity 3. Further, in order to maintain the strength and to form the runner 9, the cylindrical heat insulating layer 8 (outer space portion 8a) is made of the sealing material 13.
It is necessary to close the processed hole leaving. The sealing material 13 is preferably made of the same material as the runner plate 12.
【００２２】本実施例では、筒状断熱層は空気層により
構成しているが、空気層の代りに油などの液体、セラミ
ックスまたは有機化合物などを使用してもよい。In this embodiment, the tubular heat insulating layer is composed of an air layer, but a liquid such as oil, ceramics or an organic compound may be used instead of the air layer.
【００２３】本発明の射出成形用金型において、成形品
取り出し直後のピンゲート部の金型表面温度は、樹脂の
熱変形温度より±２０℃の範囲にあることが好ましい。
樹脂の熱変形温度より２０℃を超えると成形品の取り出
し時に糸引きが生ずる危険があり、また成形サイクルが
長くなり、加工コストが上昇する。一方、樹脂の熱変形
温度よりも２０℃近い温度に達しない温度では、ゲート
カット後のゲート跡突起が目立ち外観が良くない。In the injection mold of the present invention, the mold surface temperature of the pin gate portion immediately after taking out the molded product is preferably within ± 20 ° C. of the heat distortion temperature of the resin.
If the temperature exceeds 20 ° C. above the heat distortion temperature of the resin, there is a risk of stringing when the molded product is taken out, the molding cycle becomes long, and the processing cost increases. On the other hand, at a temperature that does not reach a temperature close to 20 ° C. higher than the heat deformation temperature of the resin, the gate mark protrusions after the gate cutting are conspicuous and the appearance is not good.
【００２４】上記のように、成形品取り出し直後のピン
ゲート部の金型表面温度を熱変形温度より±２０℃の範
囲、望ましくは熱変形温度−１０℃と熱変形温度との間
に設定するためには、断熱層の大きさを、深さ０．２〜
２０ｍｍ、長さ０．５〜５０ｍｍにすることが好まし
い。As described above, the mold surface temperature of the pin gate portion immediately after taking out the molded product is set within a range of ± 20 ° C from the heat deformation temperature, preferably between the heat deformation temperature of -10 ° C and the heat deformation temperature. The heat insulation layer has a depth of 0.2 to
It is preferable that the length is 20 mm and the length is 0.5 to 50 mm.
【００２５】[0025]
【発明の効果】以上のように、本発明の射出成形用金型
は、ピンゲート及びその上流に接続された樹脂流路を有
する合成樹脂の射出成形用金型において、上記樹脂流路
の上記ピンゲートに近い部位を筒状囲壁により構成し、
この筒状囲壁の外側空間部に筒状断熱層を配設したの
で、ゲート部の樹脂温度を樹脂の熱変形温度近傍に保持
して溶融樹脂を射出し、成形を行うことにより、ゲート
部での分子配向が緩和され、このため、従来の射出成形
に比べてゲート切り離し後のゲート跡の突起高さを著し
く低減させることになり、射出成形品の外観が向上し、
ゲート位置を沈めるなどのデザイン上の制約を受けなく
なる。As described above, the injection molding die of the present invention is a synthetic resin injection molding die having a pin gate and a resin flow path connected to the upstream of the pin gate. The part close to is composed of a cylindrical wall,
Since the tubular heat insulating layer is provided in the outer space of the tubular surrounding wall, the resin temperature of the gate portion is maintained near the thermal deformation temperature of the resin, the molten resin is injected, and molding is performed. The molecular orientation of the is relaxed, and as a result, the projection height of the gate mark after the gate is cut off is significantly reduced compared to conventional injection molding, and the appearance of the injection molded product is improved.
No more design restrictions such as sinking the gate position.
【００２６】さらにまた、この発明によれば、前記した
構成により、ゲート部が高温に保持されるため、ジェッ
ティング等の不良現象が発生しにくく、保圧が成形品末
端まで行き届き、成形性が向上し、成形品の外観が良好
となり、しかも、何等成形サイクルに影響を与えないと
いう効果がある。Further, according to the present invention, since the gate portion is kept at a high temperature by the above-mentioned constitution, a defective phenomenon such as jetting is unlikely to occur, and the holding pressure reaches the end of the molded product, and the moldability is improved. There is an effect that the molded product is improved, the appearance of the molded product is improved, and the molding cycle is not affected.
【図１】本発明による第１実施例の金型の断面図であ
る。FIG. 1 is a sectional view of a mold according to a first embodiment of the present invention.
【図２】本発明による第２実施例の金型の断面図であ
る。FIG. 2 is a sectional view of a mold according to a second embodiment of the present invention.
【図３】従来のピンゲートの断面図である。FIG. 3 is a cross-sectional view of a conventional pin gate.
【図４】従来のピンゲート跡を示す射出成形品の断面図
である。FIG. 4 is a cross-sectional view of an injection molded product showing a conventional pin gate mark.
１ 固定側金型 ２ 可動側金型 ３ キャビティ ４ ピンゲート ５ 第２スプルー ６ ピンゲートブッシュ ６ａ 筒状囲壁 ６ｂ キャビティ壁 ７ 射出成形用金型 ８ 筒状断熱層 ８ａ 外側空間部 ９ ランナ １０ 第１スプルー １１ ロケートリング １２ ランナプレート １３ 封止材 １４ 射出成形品 １５ ピンゲート跡 ｄ ゲート径 Ｌ ランド長 ｈ ゲート跡高さ 1 Fixed Side Mold 2 Movable Side Mold 3 Cavity 4 Pin Gate 5 Second Sprue 6 Pin Gate Bushing 6a Cylindrical Surrounding Wall 6b Cavity Wall 7 Injection Molding Mold 8 Cylindrical Insulation Layer 8a Outside Space 9 Runner 10 First Sprue 11 Locate ring 12 Runner plate 13 Sealant 14 Injection molded product 15 Pin gate trace d Gate diameter L Land length h Gate trace height
Claims (1)
脂流路を有する合成樹脂の射出成形用金型において、上
記樹脂流路の上記ピンゲートに近い部位を筒状囲壁によ
り構成し、この筒状囲壁の外側空間部に筒状断熱層を配
設してなることを特徴とする射出成形用金型。1. A synthetic resin injection molding die having a pin gate and a resin flow path connected to the upstream of the pin gate, wherein a portion of the resin flow path near the pin gate is formed by a cylindrical surrounding wall. A mold for injection molding, characterized in that a cylindrical heat insulating layer is disposed in the outer space of the.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20510695A JPH0929783A (en) | 1995-07-20 | 1995-07-20 | Injection mold |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20510695A JPH0929783A (en) | 1995-07-20 | 1995-07-20 | Injection mold |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0929783A true JPH0929783A (en) | 1997-02-04 |
Family
ID=16501525
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20510695A Pending JPH0929783A (en) | 1995-07-20 | 1995-07-20 | Injection mold |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0929783A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013146935A (en) * | 2012-01-20 | 2013-08-01 | Loyal Engineering Kk | Bush for injection molding |
| JP2022109278A (en) * | 2022-04-26 | 2022-07-27 | 龍江精工株式会社 | Mini gate bush for injection molding |
-
1995
- 1995-07-20 JP JP20510695A patent/JPH0929783A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013146935A (en) * | 2012-01-20 | 2013-08-01 | Loyal Engineering Kk | Bush for injection molding |
| JP2022109278A (en) * | 2022-04-26 | 2022-07-27 | 龍江精工株式会社 | Mini gate bush for injection molding |
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