JP3632257B2

JP3632257B2 - Mold heating apparatus, heating / cooling apparatus and method thereof

Info

Publication number: JP3632257B2
Application number: JP26179995A
Authority: JP
Inventors: 光雄小倉
Original assignee: Toyoda Gosei Co Ltd
Current assignee: Toyoda Gosei Co Ltd
Priority date: 1995-10-09
Filing date: 1995-10-09
Publication date: 2005-03-23
Anticipated expiration: 2015-10-09
Also published as: JPH09104048A

Description

【０００１】
【発明の属する技術分野】
本発明は金型の加熱装置、加熱冷却装置及びその方法に関するものであり、特に、射出成形前に金型の成形面を予め加熱して、射出成形品の品質の向上等を図ることができる装置及び方法に関するものである。
【０００２】
【従来の技術】
一般に、樹脂成形金型のキャビティ表面の温度を高くした状態で樹脂の射出を行うと、成形品の外観品質及び光学特性等が向上することが知られている。そして、従来のこの種の金型の加熱装置として、特公昭６０−５６６０４号公報、特開昭６２−１７９９１２号公報、特開昭６２−１１１８３２号公報、特開昭６３−１５７０７号公報、特開昭６２−２０８９１８号公報、特開昭５８−１２７１４号公報、または特開昭５８−２１１４０５号公報に掲載の技術を挙げることができる。例えば、特公昭６０−５６６０４号公報の技術は、高周波誘導加熱により、予めキャビティ表面温度を上げた状態で樹脂の射出を行う。なお、特開昭６２−１１１８３２号公報及び特開昭６３−１５７０７号公報は、類似の技術を開示している。また、特開昭６２−１７９９１２号公報の技術は、金型内の流路へ温水若しくは温油等の加熱媒体と冷却媒体とを交互に流通し、キャビティ温度を上下させる。なお、特開昭６２−２０８９１８号公報、特開昭５８−１２７１４号公報及び特開昭５８−２１１４０５号公報は、類似の技術を開示している。その他、この種の技術として、ジュール熱加熱により、または、金型に内蔵したヒータにより、金型のキャビティ表面を能動的に加熱したり、或るいは、ＳＳＩ（スポットレスサーフェスインジェクション）成形法により、射出溶融樹脂によりキャビティ表面を受動的に加熱する方法がある。
【０００３】
【発明が解決しようとする課題】
しかし、特公昭６０−５６６０４号公報の技術は、高周波誘導加熱を利用するため、高周波発振子等の高周波発生手段が必要となる等、設備コストが上昇する。また、一般的には、成形材料である樹脂の熱変形温度以上にキャビティ表面温度を上げる必要があるが、特開昭６２−１７９９１２号公報の技術は、加熱媒体の温度が低く、加熱性能が不十分となる可能性がある。即ち、高周波誘導加熱、ジュール熱加熱、ＳＳＩ成形法等の特殊な加熱方法は、加熱性能が高い反面、設備コストが増加し、また、保全性が低下するといった不具合がある。一方、金型に内蔵したヒータによる加熱、または、金型内部を流通する温水または温油による加熱等の一般的な加熱方法は、上記特殊な加熱方法と比較して、設備コストを低減でき、保全性も良好とすることができる反面、加熱性能の点で改善する余地がある。
【０００４】
そこで、本発明は、良好な加熱性能を有し、かつ、設備コストを低減し、保全性を向上することができる金型の加熱装置及びその方法の提供を第１の課題とするものである。
【０００５】
また、本発明は、良好な加熱冷却性能を有し、かつ、設備コストを低減し、保全性を向上することができる金型の加熱冷却装置及びその方法の提供を第２の課題とするものである。
【０００６】
【課題を解決するための手段】
請求項１の発明にかかる金型の加熱冷却装置は、入子移動手段により、型締め時は、金型本体に入子の裏面を当接させると共に、型開き時には入子の裏面を金型本体から離脱して、入子の裏面と金型本体との間に所定空間を形成する。一方、外部加熱手段を、型締め時は入子と干渉しない位置に退避すると共に、型開き時には入子の成形面及び裏面のいずれかに対向する位置へ進出して熱伝達により前記成形面を直接的に、または、前記裏面を介して間接的に加熱する。更に、金型本体に設けた冷却手段を、型締め時に入子の裏面に当接し、裏面を介して前記成形面を冷却する。
【０００７】
請求項２の発明にかかる金型の加熱冷却装置は、キャビティ入子移動手段により、型締め時は、金型本体にキャビティ入子の裏面を当接させ、型開き時にはキャビティ入子の裏面を金型本体から離脱して裏面と金型本体との間に所定空間を形成する。また、外部加熱手段を、型締め時はキャビティ入子と干渉しない位置に退避すると共に、型開き時にはキャビティ入子の裏面に当接する位置へ進出して熱伝導により前記裏面を介して前記キャビティ面を加熱する。更に、金型本体に設けた冷却手段を、型締め時にキャビティ入子の裏面に当接し、裏面を介して前記キャビティ面を冷却する。
【０００８】
請求項３の発明にかかる金型の加熱装置は、キャビティ入子移動手段により、型締め時は、金型本体にキャビティ入子の裏面を当接させ、型開き時にはキャビティ入子の裏面を金型本体から離脱して裏面と金型本体との間に所定空間を形成する。また、第１の外部加熱手段を、型締め時はキャビティ入子と干渉しない位置に退避すると共に、型開き時にはキャビティ入子の裏面に当接する位置へ進出して熱伝導により前記裏面を介して前記キャビティ面を加熱する。一方、第２の外部加熱手段を、型締め時はキャビティ入子と干渉しない位置に退避すると共に、型開き時にはキャビティ入子のキャビティ面に所定間隙をおいて接近対向する位置へ進出して熱輻射により前記キャビティ面を加熱する。更に、金型本体に設けた冷却手段を、型締め時にキャビティ入子の裏面に当接し、裏面を介して前記キャビティ面を冷却する。
【０００９】
請求項４の発明にかかる金型の加熱装置は、請求項３の発明において、第２の外部加熱手段を、キャビティ入子のキャビティ面を加工した放電加工電極により構成したものである。
【００１０】
請求項５の発明にかかる金型の加熱装置は、請求項３の発明において、第２の外部加熱手段を、型開き時にキャビティ入子のキャビティ面に所定間隙をおいて接近対向する第１の加熱面と、第１の加熱面に延設され、型開き時にキャビティ入子のパーティング面に当接して熱伝導によりパーティング面を介してキャビティ面を加熱する第２の加熱面より構成したものである。
【００１１】
請求項６の発明にかかる金型の加熱装置は、請求項２乃至４のいずれか一項に記載の発明において、入子の少なくともキャビティ面に対応する部分の肉厚を０．５mm乃至１５mmの範囲としたものである。
【００１２】
請求項７の発明にかかる金型の加熱方法は、型開きに伴い、入子の裏面を金型本体から離脱して前記裏面と金型本体との間に所定空間を形成する。次に、熱源としての外部加熱手段を前記空間内へ進出し、入子の裏面に対向配置して熱伝達により前記裏面を介して前記成形面を加熱する。
【００１３】
請求項８の発明にかかる金型の加熱冷却方法は、型開きに伴い、入子の裏面を金型本体から離脱して前記裏面と金型本体との間に所定空間を形成する。次に、熱源としての外部加熱手段を前記空間内へ進出し、入子の裏面に対向配置して熱伝達により前記裏面を介して前記成形面を加熱する。その後、型締めに伴い、外部加熱手段を前記空間から退避すると共に、入子の裏面に冷却手段を当接し、裏面を介して前記成形面を冷却する。
【００１４】
【発明の実施の形態】
以下、本発明の実施の形態を説明する。
【００１５】
図１は本発明の第一の実施形態の金型の加熱冷却装置による金型の冷却時を示す説明図である。図２は本発明の第一の実施形態の金型の加熱冷却装置による金型の加熱時を示す説明図である。図３は本発明の第一の実施形態の金型の加熱冷却装置の加熱手段による加熱状態を示す断面図である。図４は本発明の第一の実施形態の金型の加熱冷却装置の加熱手段を示す要部拡大断面図である。図５は本発明の第一の実施形態の金型の加熱冷却装置の冷却手段による冷却状態を示す断面図である。
【００１６】
本実施形態の加熱冷却装置は射出成形金型に具体化されるものであるため、まず、射出成形金型の構造の概略について説明する。
【００１７】
図１及び図２において、本実施形態の射出成形金型は、可動側ダイプレート１１に可動側取付板１２及びスペーサブロック１３を介して可動主型１４を取付けている。可動主型１４の右側面には、右方へ突出する断面凸状のコア面１４ａが形成され、そのコア面１４ａにより成形空間Ｓの一部（内側面部）を構成している。また、前記スペーサブロック１３内の空間には押出板１５を介して押出ピン１６が右方へ突出して固定されている。前記押出ピン１６は、図１に示す型締め位置では、先端面を可動主型１４のコア面１４ａと面一とする。また、図２に示す型開き位置で、駆動機構の駆動軸１７により押出板１５が右方に移動されて、押出ピン１６の先端面が可動主型１４のコア面１４ａから右方に突出し、冷却固化後の成形品の取出を容易にするようになっている。一方、固定側ダイプレート２１には、固定側取付板２２を介して固定背板２３が固定されている。固定背板２３の右側面の中央部には射出ノズル２４導入用の導入凹部２３ａが形成されると共に、固定側取付板２２及び固定側ダイプレート２１の中央部には、前記導入凹部２３ａに連通する導入孔２２ａ，２１ａがそれぞれ穿設されている。また、前記固定背板２３の導入凹部２３ａの中心部にはスプルー２３ｂ及びランナー２３ｃが穿設され、前記両導入孔２１ａ，２２ａ及び導入凹部２３ａを介して、射出ノズル２４の先端をスプルー２３ｂに装着するようになっている。なお、以上の構成は一般的な射出成形金型の構成と同様であるため、関連部分の詳細な説明は省略する。
【００１８】
前記固定背板２３は、左側面の中央部を左方に突出する断面凸状の冷却部２３ｄとしている。前記固定背板２３の冷却部２３ｄより右側には複数の冷却孔２３ｅが前後方向（図１及び図２中紙面と直交する方向）に延設され、冷却孔２３ｅに冷却水等の冷却流体を流通することにより、冷却部２３ｄの温度を低下するようになっている。前記固定背板２３の左側面には、固定主型２４が左右への移動自在に取付けられ、図示しない固定主型移動機構により、図１に示す型締め位置と図２に示す型開き位置との間で往復移動するようになっている。固定主型２４の中央部には断熱板２５を介してキャビティ入子２６が嵌合固定されている。
【００１９】
図３に示すように、キャビティ入子２６は、成形空間Ｓの他部（外側面部）を形成するキャビティ面２６ａと、前記キャビティ面２６ａと反対側に位置する裏面２６ｂとを有している。前記キャビティ入子２６の左側面２６ｄと前記固定主型２４の左側面２４ａ及び断熱板２５の左側面２５ａとは面一とされ、パーティング面乃至パーティングラインＰＬを構成している。また、固定主型２４の右側面２４ｂ及び断熱板２５の右側面２５ｂは面一とされると共に、前記断熱板２５の中央には固定背板２３の冷却部２３ｄを密嵌する形状の収容孔２５ｃが穿設され、断熱板２５の右側面２５ｂ及びキャビティ入子２６の裏面２６ｂ間に段差状の凹部が形成されている。そして、図５に示すように、型締め状態で、冷却部２３ｄが前記収容孔２５ｃ内に密嵌され、冷却部２３ｄがキャビティ入子２６の裏面２６ｂに密接すると共に、固定主型２４の右側面２４ｂが固定背板２３の左側面２３ｆに密接するようになっている。更に、型締め状態で、固定主型２４、断熱板２５及びキャビティ入子２６の面一の左側面２４ａ，２５ａ，２６ｄは、前記可動主型１４の右側面と密接し、キャビティ入子２６のキャビティ面２６ａと可動主型１４のコア面１４ａとの間に断面略コ字状の成形空間Ｓが形成されるようになっている。なお、前記キャビティ入子２６の中心部には、前記固定背板２３のランナー２３ｃに整合して連通するゲート２６ｃが穿設されている。
【００２０】
前記固定主型２４、断熱板２５及び図示しない固定主型移動機構により、キャビティ入子２６を左右方向に往復移動するキャビティ入子移動手段が構成され、型締め時は、前記キャビティ入子２６の裏面２６ｂを金型本体としての固定背板２３の左側面２３ｆに当接させ、型開き時には、前記キャビティ入子２６の裏面２６ｂを固定背板２３の左側面２３ｆから離脱して前記裏面２６ｂと固定背板２３との間に所定間隔の空間を形成するようになっている。また、前記金型本体としての固定背板２３に設けた冷却部２３ｄ及び冷却孔２３ｅにより、型締め時に前記キャビティ入子２６の裏面２６ｂに当接し、前記裏面２６ｂを介して前記キャビティ面２６ａを冷却する冷却手段が構成されている。なお、一般の射出成形金型と同様、固定主型２４はガイドピン２７を介して固定背板２３に支持されると共に、固定主型２４及び可動主型１４はガイドピン２７を介して左右に案内され正確な型締め位置に位置合わせされるようになっている。
【００２１】
次に、本実施形態の外部加熱手段について説明する。
【００２２】
本実施形態は、図３に示すように、外部加熱手段として、キャビティ面２６ａに対応する略四角ブロック状の第１及び第２の外部加熱手段３１及び３２を備えている。第１の外部加熱手段３１は、第１の移動機構４１により、型締め時は前記キャビティ入子２６と干渉しない退避位置（図１の位置）に退避すると共に、型開き時には前記キャビティ入子２６の裏面２６ｂに密接する加熱位置（図２の位置）へ進出して熱伝導により前記裏面２６ｂを介して前記キャビティ面２６ａを加熱するようになっている。なお、第１の外部加熱手段３１の幅及び高さ（図中の前後寸法及び上下寸法）は、前記断熱板２５の収容孔２５ｃの幅及び高さよりそれぞれ所定値小さく設定され、第１の外部加熱手段３１の前後及び上下の側面が断熱板２５に当接して断熱板２５を直接加熱することを防止している。第１の外部加熱手段３１の寸法は、少なくとも、キャビティ面２６ａに対応する裏面２６ｂ部分の略全体を加熱できるよう設定し、断熱板２５の収容孔２５ｃの寸法もこれに対応して設定する。
【００２３】
ここで、前記キャビティ入子２６の肉厚は、裏面２６ｂ側からの熱伝導を良好とするため、少なくともキャビティ面２６ａに対応する部分の肉厚を１５mm以下に設定することが好ましい。特に、第１の外部加熱手段３１が当接する部分のキャビティ入子２６の肉厚をかかる範囲に設定することがより好ましい。なお、かかる肉厚を１５mmを超える値とした場合、熱電導効率が低下し、キャビテイ入子２６の裏面２６ｂ側からキャビティ面２６ａ側への熱伝達時間が長くなる可能性がある。一方、かかる肉厚は、キャビティ入子２６を切削により加工する場合、０．５mm以上とすることが好ましい。かかる肉厚を０．５mm未満とした場合、キャビティ入子２６の切削加工が困難となったり、加工作業性が低下する可能性がある。なお、切削以外の加工方法によりキャビティ入子２６をより薄肉に加工できる場合、その下限値を例えば０．２mm程度としてもよい。しかし、下限値を０．２mm未満とした場合、キャビティ入子２６が加熱時に熱変形したり、樹脂の射出圧により破損する可能性がある。
【００２４】
前記第２の外部加熱手段３２は、第２の移動機構４２により、型締め時は前記キャビティ入子２６と干渉しない退避位置（図１の位置）に退避すると共に、型開き時には前記キャビティ入子２６のキャビティ面２６ａに所定間隙ｄ１，ｄ２，ｄ３をおいて接近対向する加熱位置（図２の位置）へ進出して熱輻射により前記キャビティ面２６ａを加熱するようになっている。なお、第２の外部加熱手段３２の幅及び高さ（図中の前後寸法及び上下寸法）は、キャビティ入子２６のキャビティ面２６ａの幅及び高さよりそれぞれ所定値小さく設定され、第２の外部加熱手段３２の前後及び上下の側面がキャビティ入子２６に当接してキャビティ入子２６を直接加熱することを防止している。前記第２の外部加熱手段３２とキャビティ面２６ａとの間隙ｄ１，ｄ２，ｄ３は、熱輻射効率を高めるべくできるだけ小さくすることが望ましく、好ましくは約０．２mmとする。なお、かかる間隙を０．２mm未満とした場合、第２の外部加熱手段３２とキャビテイ面２６ａとの間に一定間隙を確保するのが困難となる可能性があり、第２の外部加熱手段３２がキャビティ面２６ａに接触して傷付きの原因となる等の可能性がある。
【００２５】
次に、第１及び第２の外部加熱手段３１，３２の構成の詳細について説明する。なお、第１の外部加熱手段も第２の外部加熱手段と同様の構成であるため、ここでは対応部分に対応する符号を付して重複した説明を省略する。
【００２６】
第１及び第２の外部加熱手段３１，３２は、図４に示すように、平板状の支持板３１ａ，３２ａ上に平板状の熱源３１ｂ，３２ｂを介して同じく平板状の熱板３１ｃ，３２ｃを載置した三層構造の四角ブロック状をなしている。前記支持板３１ａ，３２ａは、第１または第２の移動機構４１，４２側に位置し、前記第１または第２の移動機構４１，４２への熱伝達による影響を防止すべく、好ましくは、熱絶縁材料により形成する。また、前記熱源３１ｂ，３２ｂは、熱板３１ｃ，３２ｃを射出樹脂の溶融温度に対応して所望温度、例えば３５０℃付近まで一定時間内に加熱できるものであればよく、熱伝導率の良好な金属に公知の電気ヒータを内蔵したり、または、温油等の加熱流体を流通するようにしてもよい。更に、前記熱板３１ｃ，３２ｃは、銅板等、熱伝導率の良好な金属より形成する。本実施形態では、第２の外部加熱手段３２の熱板３２ｃとしては、キャビティ入子２６のキャビティ面２６ａを加工した放電加工電極を使用し、熱板３２ｃとキャビティ面２６ａとの間隙ｄ１，ｄ２，ｄ３を容易に一定値に維持するようにしている。なお、前記第１及び第２の移動機構４１，４２としては、油圧シリンダを二次元的乃至三次元的に組み合わせたもの等、公知の種々の二次元的乃至三次元的移動機構を採用することができる。
【００２７】
次に、上記のように構成された本実施形態の金型の加熱冷却装置による金型の加熱冷却方法を使用した射出成形動作について説明する。なお、この射出成形動作は、ＣＰＵ、ＲＯＭ、ＲＡＭ等からなる制御手段を使用して、ＲＯＭに予め記憶された制御プログラムに従って実施される。図６は本発明の第一の実施形態の金型の加熱冷却方法を示す工程図である。
【００２８】
まず、空間形成工程としての型開き工程において、射出成形機の型締装置（図示略）を駆動して、可動側ダイプレート１１、可動側取付板１２及びスペーサブロック１３を介して可動主型１４を左方に移動し、図２の型開き位置として、固定主型２４及び固定背板２３との間に十分な間隔を設ける。また、これと共に、固定主型２４を固定主型移動機構により左方へ移動し、キャビティ入子２６の裏面２６ｂを固定背板２３から離間し、可動主型１４と固定背板２３との間の略中間位置に配置する。これにより、図２に示すように、固定背板２３とキャビティ入子２６の裏面２６ｂとの間、及び、キャビティ入子２６のキャビティ面２６ａと可動主型１４との間に、それぞれ、所定間隔の空間が形成される。
【００２９】
次に、熱板接近工程において、第１の移動機構４１を駆動して、熱源３１ｂを有する第１の外部加熱手段３１を固定背板２３と固定主型２４との間の空間内に進出し、熱板３１ｃをキャビティ入子２６の裏面２６ｂに対向配置する。これと同時に、第２の移動機構４２を駆動して、熱源３２ｂを有する第２の外部加熱手段３２を固定主型２４と可動主型１４との間の空間に進出し、熱板３２ｃをキャビティ入子２６のキャビティ面２６ａに対向配置する。
【００３０】
そして、図２及び図３に示すように、加熱工程において、第１及び第２の移動機構４１，４２により、第１の外部加熱手段３１の熱板３１ｃをキャビティ入子２６の裏面２６ｂに密接すると共に、第２の外部加熱手段３２の熱板３２ｃをキャビティ面２６ａに所定間隙ｄ１，ｄ２，ｄ３を置いて接近配置する。すると、第１の外部加熱手段３１の熱板３１ｃが、キャビティ入子２６の裏面２６ｂを熱伝導により加熱し、裏面２６ｂ側から成形面としてのキャビティ面２６ａを間接的に加熱することになる。同時に、第２の外部加熱手段３２の熱板３２ｃが、キャビティ入子２６のキャビティ面２６ａを熱輻射により直接加熱する。なお、この加熱工程における加熱時間は、加熱対象たるキャビティ入子２６のキャビティ面２６ａ対応部分の肉厚、射出樹脂の種類に応じたキャビティ面２６ａの目標加熱値、熱板３１ｃ，３２ｃの加熱温度等に応じて適宜変更される。例えば、ＡＢＳ樹脂を射出し、キャビティ入子２６のキャビティ面２６ａ対応部分の肉厚を１０mmとし、キャビティ面２６ａの目標温度を１３０℃とする場合において、熱板３１ｃ，３２ｃの加熱温度を約３５０℃とする場合、加熱時間は約３０秒乃至４０秒とする。また、かかる条件でキャビティ入子２６のキャビティ面２６ａ対応部分の肉厚を５mmに変更した場合、２０秒以下の加熱時間でキャビティ面２６ａを上記温度と同等温度とすることができ、また、この場合、加熱時間を１分とすると、キャビティ面２６ａ温度を約２００℃とすることができる。このとき、断熱板２５がキャビティ入子２６の放熱を防止している。また、第２の外部加熱手段３２の熱板３２ｃを放電加工電極により構成したため、キャビティ面２６ａとの隙間を０．２mmという、極めて小さく、かつ、均一な間隔とすることができ、熱輻射を効率良く行うことができると共に、当接による傷付き等を防止することができる。更に、キャビティ入子２６を可能な限り薄肉としたため、裏面２６ｂ側からの熱伝導を効率良く行える。なお、前記キャビティ面２６ａ温度自体は、通常の金型温度調整技術と同様、樹脂の種類、加熱変形温度等に応じて決定される。
【００３１】
その後、熱板離間工程において、第１の移動機構４１により、第１の外部加熱手段３１の熱板３１ｃをキャビティ入子２６の裏面２６ｂに当接する位置から離間し、キャビティ入子２６と固定背板２４との間の空間から図１の退避位置に退避する。同時に、第２の移動機構４２により、第２の外部加熱手段３２の熱板３２ｃをキャビティ入子２６のキャビティ面２６ａに接近する位置から離間し、前記キャビティ入子２６と可動主型１４との間の空間から図１の退避位置に退避する。
【００３２】
かかる後、型締め工程において、固定主型移動機構を駆動して、固定主型２４を固定背板２３に型締めすると共に、型締装置を駆動して、可動側ダイプレート１１、可動側取付板１２及びスペーサブロック１３を介して、可動主型１４を固定主型２４及び固定背板２３に対し型締めする。すると、可動主型１４とキャビティ入子２６が、パーティング面にて型締めされ、コア面１４ａ及びキャビティ面２６ａ間に成形品形状と同一形状の成形空間Ｓが形成されると共に、固定背板２３のスプルー２３ｂ及びランナー２３ｃが、キャビティ入子２６のゲート２６ｃに連通する。同時に、キャビティ入子２６の裏面２６ｂに固定背板２３の冷却部２３ｄが密接する。この状態で、射出ノズル２４先端をスプルー２３ｂに圧接することにより、射出ノズル２４からスプルー２３ｂ、ランナ２３ｃ及びゲート２６ｃを介して、前記成形空間Ｓ内に溶融樹脂を射出注入可能となる。
【００３３】
そして、射出冷却工程の射出工程で、射出装置（図示略）から射出ノズル２４を介してスプルー２３ｂに溶融樹脂を射出注入し、ランナ２３ｃを介してゲート２６ｃからキャビティ面２６ａ及びコア面１４ａ間に形成される成形空間Ｓ内に溶融樹脂を充填する。このとき、キャビティ面２６ａが所望温度に加熱されているため、キャビティ面２６ａに接する溶融樹脂は、確実に加熱変形温度（例えば、ＡＢＳ樹脂の場合１６０℃乃至１７０℃）を維持し、フローマーク、シルバーストリーク（銀条痕）等の発生を確実に防止することができる。また、射出時点で、キャビティ入子２６の裏面２６ｂに固定背板２３の冷却部２３ｄが密接しているため、固定背板２３の冷却孔２３ｅに大量の冷却水等、冷却流体を供給及び流通することにより、冷却手段としての冷却部２３ｄによりキャビティ入子２６の裏面２６ｂを瞬時に冷却し、熱伝導によりキャビティ面２６ａを急速に冷却することができ、溶融樹脂の冷却固化を十分に促進することができる。このとき、キャビティ入子２６を可能な限り薄肉としたため、冷却効率を向上することができる。これにより、射出樹脂が加熱変形温度以下となって迅速に冷却固化し、成形空間Ｓに対応する所定形状の成形品が迅速に成形される。なお、上記溶融樹脂の射出から冷却固化までの間における前記キャビティ面２６ａの温度勾配は、キャビティ面２６ａの初期設定加熱温度及び冷却部２３ｄの設定冷却温度により適宜調整可能である。
【００３４】
その後、図３に示す型開き工程で、型締め装置を駆動して、可動主型１４を固定主型２４から離間して型開きする。これにより、コア面１４ａとキャビティ面２６ａとが型開きされて、成形品がキャビティ面２６ａから離型してコア面１４ａ上に残る。その後、製品取出工程で、押出駆動手段（図示略）を駆動し、押出ピン１６をコア面１４ａから突出して、成形品をコア面１４ａから押出して離脱し、製品の取出を行う。
【００３５】
以後、上記一連の工程を繰返し、所望形状の樹脂成形品を連続して得ることができる。
【００３６】
このように、上記実施形態の金型の加熱冷却装置は、成形空間Ｓの一部を形成するキャビティ面２６ａ及び前記キャビティ面２６ａと反対側に位置する裏面２６ｂを有するキャビティ入子２６に接続され、型締め時は金型本体としての固定背板２３に前記キャビティ入子２６の裏面２６ｂを当接させ、型開き時には前記キャビティ入子２６の裏面２６ｂを前記固定背板２３から離脱して前記裏面２６ｂと固定背板２３との間に所定空間を形成するキャビティ入子移動手段２４としての固定主型２４、断熱板２５及び固定主型移動機構と、第１の移動機構４１により、型締め時は前記キャビティ入子２６と干渉しない位置に退避すると共に、型開き時には前記キャビティ入子２６の裏面２６ｂに当接する位置へ進出して、熱板３１ｃからの熱伝導により前記裏面２６ｂを介して前記キャビティ面２６ａを加熱する第１の外部加熱手段３１と、第２の移動機構４２により、型締め時は前記キャビティ入子２６と干渉しない位置に退避すると共に、型開き時には前記キャビティ入子２６のキャビティ面２６ａに所定間隙をおいて接近対向する位置へ進出して、熱板３２ｃからの熱輻射により前記キャビティ面２６を加熱する熱板３２ｃを有する第２の外部加熱手段３２と、前記固定背板２３に設けられ、型締め時に前記キャビティ入子２６の裏面２６ｂに当接し、裏面２６ｂを介してキャビティ面２６ａを冷却する冷却手段としての冷却部２３ｄ及び冷却孔２３ｅを具備する。
【００３７】
したがって、上記実施形態は、金型の加熱時には、冷却部２３ｄがキャビティ入子２６から離間され、キャビティ入子２６を冷却することはないため、第１及び第２の外部加熱手段３１，３２によるキャビティ入子２６の加熱を効率よく、かつ、迅速に行うことができる。また、金型の冷却時には、第１及び第２の外部加熱手段３１，３２をキャビティ入子２６から退避し、キャビティ入子２６を加熱することはないため、冷却部２３ｄによるキャビティ入子２６の冷却を効率よく、かつ、迅速に行うことができ、樹脂の冷却固化速度を増加することができる。その結果、加熱性能及び冷却性能をそれぞれ向上することができ、金型の加熱後の樹脂射出から、金型の冷却に伴う樹脂の固化及び取出し迄の成形サイクルを大幅に短縮することができる。また、第１及び第２の外部加熱手段３１，３２と冷却部２３ｄとを、熱的に分離した形で独立して動作するため、射出樹脂の種類等に応じて、キャビティ面２６ａ温度の最適熱勾配を容易かつ迅速に得ることができ、製品品質を向上することができる。即ち、従来のように、金型に内蔵したヒータまたは温水、温油等の加熱源による加熱の場合、加熱源自体の温度が下がりにくく、冷却時の熱応答性が十分とはいえなかったが、本実施形態は、加熱源としての第１及び第２の外部加熱手段３１，３２を金型から空間的に離れた位置に退避するため、被加熱源である金型絡み他場合の熱応答性を大きくすることができる。そして、樹脂材料重点開始時の金型温度を高くすることにより、成形品の外観を良好とし、かつ、型締め直後から開始する冷却部２３ｄによる除熱作用によって金型温度を下げることにより、成形品の取出までに必要な成形サイクルを短縮することができる。換言すれば、本実施形態装置は、金型温度の大幅な変化を可能とすることで、高品質の成形品を高い成形サイクルで生産することができる。
【００３８】
そして、加熱手段としては金型内蔵タイプのものでなく、第１及び第２の外部加熱手段３１，３２といった金型外部に配置するタイプのものを使用する一方、その熱源３１ｂ，３２ｂ自体としては、電熱ヒータ等、比較的簡単な構成の公知の熱源を用いることができるため、高周波誘導加熱またはＳＳＩ成形のような高価乃至複雑な構成を用いる場合と比較して、設備コストを大幅に低減することができると共に、その保守等も容易で、保全性を向上することができる。更に、第２の外部加熱手段３２が成形品の表面品質を決定するキャビティ面２６ａに直接当接しないため、その傷付き及び加熱酸化による金属焼け等の品質劣化を防止することができ、製品自体の品質を良好に維持することができる。
【００３９】
また、キャビティ入子２６の肉厚を、少なくともキャビティ面２６ａ対応部分で約０．５mm〜１５mmの範囲とすることにより、キャビティ入子２６の裏面２６ｂ側からのキャビティ面２６ａの加熱をより効率よく迅速に行うことができ、キャビティ面２６ａの温度上昇を一層増加することができる。そして、第２の外部加熱手段３２の熱板３２ｃとキャビティ面２６ａとの間隙ｄ１，ｄ２，ｄ３を約０．２mmと小さくすることにより、第２の外部加熱手段３２からの熱輻射による加熱効率を高めることができる。その結果、キャビティ面２６ａの加熱時間をより一層短縮化して、全体の成形サイクルを一層短くすることができる。更に、第１の外部加熱手段３１の熱板３１ｃは、成形品の品質に影響を及ぼさないキャビテイ入子２６の裏面２６ｂに直接密接するため、成形品の品質を良好に維持する一方、キャビティ面２６ａの加熱を一層効率よく行うことができる。
【００４０】
また、キャビティ入子２６を断熱板２５を介して固定主型２４に取付けたため、断熱板２５によりキャビティ入子２６に蓄えた熱の放散を防止することができる。更に、第１及び第２の外部加熱手段３１，３２の支持板３１ａ，３２ａを熱絶縁材料により構成することにより、第１及び第２の外部加熱手段３１，３２からの熱放散を有効に防止することができると共に、第１及び第２の移動機構４１，４２への熱伝導による影響を防止することができる。
【００４１】
次に、本発明による第二の実施形態を以下に説明する。なお、本実施形態においては上記第一の実施形態との相違点のみを説明し、上記第一の実施形態と同一の構成については図面に同一符号を付してその説明を省略する。
【００４２】
図７は本発明の第二の実施形態の金型の加熱冷却装置の加熱手段による加熱状態を示す断面図である。
【００４３】
本実施形態は、第２の外部加熱手段５１の熱板対応部分の形状を第一の実施形態と相違させたものであり、その他の構成は第一の実施形態と同様である。即ち、第２の外部加熱手段５１の少なくとも熱板対応部分は、型開き時に前記キャビティ入子２６のキャビティ面２６ａに所定間隙をおいて接近対向する第１の加熱面５１ａと、前記第１の加熱面５１ａに延設され、型開き時に前記キャビティ入子２６の左側面２６ｄからなるパーティング面に当接して熱伝導により前記パーティング面を介して前記キャビティ面２６ａを加熱する第２の加熱面５１ｂを有する。前記第１の加熱面５１ａは第一の実施形態の第２の外部加熱手段３２の熱板３２ｃと同様、キャビティ面２６ａとの間に所定の小さな間隙を置いて、熱輻射によりキャビティ面２６ａを加熱する。
【００４４】
本実施形態は、第一の実施形態と同様の作用及び効果に加え、第２の外部加熱手段５１によるキャビティ面２６ａ側からのキャビティ面２６ａの加熱をより一層効率よくかつ短時間で行うことができるという効果を奏する。
【００４５】
ところで、上記各実施形態は、金型の加熱冷却装置及びその方法に具体化して説明したが、本発明を実施する場合には、少なくともキャビティ入子移動手段及び第１または第２の外部加熱手段３１，３２，５１からなる金型の加熱装置に具体化してもよい。更に、金型として、射出成形金型以外にも、キャビティ面の予備加熱が有効と考えられるものに具体化してもよい。
【００４６】
また、上記各実施形態のように、第１または第２の外部加熱手段３１，３２を支持板３１ａ，３２ａ、熱源３１ｂ，３２ｂ及び熱板３１ｃ，３２ｃの三層構造とすることなく、熱源を内蔵した一層構造とする等、他の構成としてもよい。なお、この場合、第二の実施形態の第２の外部加熱手段５１は、少なくとも熱板部分を前記第１及び第２の加熱面５１ａ，５１ｂより構成する。
【００４７】
そして、上記各実施形態は、第２の外部加熱手段３２，５１とキャビティ面２６ａとの間に所定間隙ｄ１，ｄ２，ｄ３を設けたが、熱板３２ｃを銅板等、キャビティ入子２６より硬度の低い材料にて形成した場合、第２の外部加熱手段３２，５１をキャビティ面２６ａに当接し、直接熱伝導により加熱することも可能である。しかし、キャビティ面２６ａにシボ模様を設けるタイプの金型の場合、やはり第２の外部加熱手段３２，５１とキャビティ面２６ａとの間に所定の間隙を設ける必要がある。
【００４８】
更に、この装置及び方法は、成形空間Ｓを形成するコア面１４ａ及びキャビティ面２６ａの少なくとも一方の成形面を、冷却手段と熱的に分離した状態で、外部加熱手段により射出前に予備加熱するものであればよく、例えば、コア面をコア入子に設け、キャビティ面ではなくコア入子のコア面及び裏面の少なくとも一方を外部加熱手段により加熱してもよい。この場合、外部加熱手段の熱板の形状は、コア入子のコア面形状及び裏面形状にそれぞれ対応させる。また、上記各実施形態とは逆に、コア面を可動主型側ではなく固定主型側に設け、キャビティ面を可動主型側に設けてもよい。そして、冷却手段も上記実施形態のものに限定することなく、他の冷却手段も採用することができる。
【００４９】
なお、本明細書中において、「金型本体」とは、キャビティ入子２６またはコア入子に隣接して、これらに当接する金型部分をいい、上記実施形態では、固定背板２３をいう。また、コア面をコア入子に設けてコア入子を加熱する場合、コア入子が隣接する可動背板が金型本体となる。
【００５０】
【発明の効果】
以上のように、請求項１の発明にかかる金型の加熱装置は、入子の裏面を、冷却手段を設けた金型本体から空間的に分離し、熱的にほぼ絶縁した状態で、外部加熱手段により入子の成形面の加熱を行うことができるため、加熱効率が向上する。また、成形面の加熱を裏面側から行うため、成形面の傷付き、加熱酸化による金属焼け等のおそれを防止することができる。更に、入子の冷却時には、外部加熱手段が金型本体から空間的に分離し、熱的にほぼ絶縁した状態で、入子の成形面の冷却を行うことができるため、冷却効率が向上する。その結果、金型温度の大幅な変化が可能となり、高品質の成形品を短い成形サイクルで生産することができる。
【００５１】
請求項２の発明にかかる金型の加熱冷却装置は、キャビティ入子の裏面を、冷却手段を設けた金型本体から空間的に分離し、熱的にほぼ絶縁した状態で、外部加熱手段によりキャビティ入子の成形面の加熱を行うことができるため、加熱効率が向上する。また、成形面の加熱を裏面側から行うため、成形面の傷付き、加熱酸化による金属焼け等のおそれを防止することができる。更に、キャビティ入子の冷却時には、外部加熱手段が金型本体から空間的に分離し、熱的にほぼ絶縁した状態で、キャビティ入子の成形面の冷却を行うことができるため、冷却効率が向上する。その結果、金型温度の大幅な変化が可能となり、高品質の成形品を短い成形サイクルで生産することができる。
【００５２】
請求項３の発明にかかる金型の加熱冷却装置は、キャビティ入子の裏面を、冷却手段を設けた金型本体から空間的に分離し、熱的にほぼ絶縁した状態で、第１及び第２の外部加熱手段によりキャビティ入子の成形面の加熱を行うことができるため、加熱効率が向上する。また、第１の外部加熱手段を直接キャビティ入子の裏面に当接して熱伝導により成形面を間接的に加熱するため、成形面の傷付き、加熱酸化による金属焼け等のおそれを防止し、かつ、加熱効率を一層高めることができる。一方、第２の外部加熱手段はキャビティ面を熱輻射により直接加熱するため、成形面の傷付き、加熱酸化による金属焼け等のおそれを防止し、かつ、加熱効率を一層高めることができる。更に、キャビティ入子の冷却時には、第１及び第２の外部加熱手段が金型本体から空間的に分離し、熱的にほぼ絶縁した状態で、キャビティ入子の成形面の冷却を行うことができるため、冷却効率が向上する。その結果、金型温度の大幅な変化が可能となり、高品質の成形品を短い成形サイクルで生産することができる。
【００５３】
請求項４の発明にかかる金型の加熱冷却装置は、請求項３の発明に加え、第２の外部加熱手段をキャビティ面形状に対応させるために通常行う特別な加工が不要となり、部品コストを低減できると共に、第２の外部加熱手段とキャビティ面との間の所定間隙を容易に、かつ、精度良く設けることができる。
【００５４】
請求項５の発明にかかる金型の加熱冷却装置は、請求項３の発明に加え、第２の外部加熱手段の第２の加熱面が、キャビティ入子のパーティング面に直接当接して、熱伝導により直近に位置するキャビティ面を効率良く加熱する。また、第１の加熱面は、熱輻射によりキャビティ面を効率良く加熱する。その結果、成形サイクルを一層短縮化することができる。
【００５５】
請求項６の発明にかかる金型の加熱冷却装置は、請求項２乃至４のいずれか一項に記載の発明に加え、キャビティ入子の肉厚が十分小さいため、第１の外部加熱手段によるキャビティ入子の裏面側からの熱伝導加熱をより効率良く行うことができる。
【００５６】
請求項７の発明にかかる金型の加熱方法は、入子の裏面を、金型本体から空間的に分離し、熱的にほぼ絶縁した状態で、前記外部加熱手段により入子の成形面の加熱を行うことができるため、加熱効率が向上する。その結果、金型温度の大幅な変化が可能となり、高品質の成形品を短い成形サイクルで生産することができる。
【００５７】
請求項８の発明にかかる金型の加熱冷却方法は、入子の裏面を、冷却手段を設けた金型本体から空間的に分離し、熱的にほぼ絶縁した状態で、外部加熱手段により入子の成形面の加熱を行うことができるため、加熱効率が向上する。また、成形面の加熱を裏面側から行うため、成形面の傷付き、加熱酸化による金属焼け等のおそれを防止することができる。更に、入子の冷却時には、前記外部加熱手段が金型本体から空間的に分離し、熱的にほぼ絶縁した状態で、入子の成形面の冷却を行うことができるため、冷却効率が向上する。その結果、金型温度の大幅な変化が可能となり、高品質の成形品を短い成形サイクルで生産することができる。
【図面の簡単な説明】
【図１】図１は本発明の第一の実施形態の金型の加熱冷却装置による金型の冷却時を示す説明図である。
【図２】図２は本発明の第一の実施形態の金型の加熱冷却装置による金型の加熱時を示す説明図である。
【図３】図３は本発明の第一の実施形態の金型の加熱冷却装置の加熱手段による加熱状態を示す断面図である。
【図４】図４は本発明の第一の実施形態の金型の加熱冷却装置の加熱手段を示す要部拡大断面図である。
【図５】図５は本発明の第一の実施形態の金型の加熱冷却装置の冷却手段による冷却状態を示す断面図である。
【図６】図６は本発明の第一の実施形態の金型の加熱冷却方法を示す工程図である。
【図７】図７は本発明の第二の実施形態の金型の加熱冷却装置の加熱手段による加熱状態を示す断面図である。
【符号の説明】
１４ａコア面（成形面）
２３固定背板（金型本体）
２３ｄ冷却部（冷却手段）
２３ｅ冷却孔（冷却手段）
２４固定主型（入子移動手段、キャビティ入子移動手段）
２５断熱板（入子移動手段、キャビティ入子移動手段）
２６キャビティ入子（入子）
２６ａキャビティ面（成形面）
３１第１の外部加熱手段（外部加熱手段）
３２第２の外部加熱手段（外部加熱手段）
５１第２の外部加熱手段（外部加熱手段）
５１ａ第１の加熱面
５１ｂ第２の加熱面
Ｓ成形空間[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mold heating apparatus, a heating / cooling apparatus, and a method thereof, and in particular, can improve the quality of an injection molded product by preheating the mold surface before injection molding. The present invention relates to an apparatus and a method.
[0002]
[Prior art]
Generally, it is known that when the resin is injected with the temperature of the cavity surface of the resin molding die being increased, the appearance quality and optical characteristics of the molded product are improved. As this type of conventional mold heating apparatus, Japanese Patent Publication No. Sho 60-56604, Japanese Patent Publication No. Sho 62-179912, Japanese Patent Publication No. Sho 62-111182, Japanese Patent Publication No. Sho 63-15707, Techniques described in Japanese Laid-Open Patent Publication No. 62-208918, Japanese Laid-Open Patent Publication No. 58-12714, or Japanese Laid-Open Patent Publication No. 58-21405 can be cited. For example, the technique disclosed in Japanese Patent Publication No. 60-56604 performs resin injection with the cavity surface temperature raised in advance by high-frequency induction heating. Note that Japanese Patent Laid-Open Nos. Sho 62-111182 and 63-15707 disclose similar techniques. In the technique disclosed in JP-A-62-179912, a heating medium such as hot water or hot oil and a cooling medium are alternately circulated through the flow path in the mold to raise and lower the cavity temperature. JP-A-62-208918, JP-A-58-12714 and JP-A-58-21405 disclose similar techniques. In addition, as this kind of technology, the cavity surface of the mold is actively heated by Joule heating or a heater built in the mold, or by SSI (Spotless Surface Injection) molding method. There is a method of passively heating the cavity surface with an injection molten resin.
[0003]
[Problems to be solved by the invention]
However, the technique disclosed in Japanese Patent Publication No. 60-56604 uses high-frequency induction heating, so that high-frequency generating means such as a high-frequency oscillator is required, resulting in an increase in equipment cost. In general, it is necessary to raise the cavity surface temperature to be higher than the heat deformation temperature of the resin that is a molding material. However, the technique of Japanese Patent Application Laid-Open No. Sho 62-179912 has a low heating medium temperature and has a heating performance. It may be insufficient. That is, special heating methods such as high-frequency induction heating, Joule heating, and SSI molding have high heating performance, but have the disadvantages of increased equipment costs and poor maintainability. On the other hand, general heating methods such as heating with a heater built in the mold or heating with hot water or hot oil circulating inside the mold can reduce the equipment cost compared to the above special heating method, While maintainability can be improved, there is room for improvement in terms of heating performance.
[0004]
SUMMARY OF THE INVENTION Accordingly, a first object of the present invention is to provide a mold heating apparatus and method that have good heating performance, reduce equipment costs, and improve maintainability. .
[0005]
Moreover, this invention makes it a 2nd subject to provide the heating-cooling apparatus of the metal mold | die which has favorable heating-cooling performance, can reduce installation cost, and can improve maintainability, and its method. It is.
[0006]
[Means for Solving the Problems]
Claim 1 The mold heating / cooling device according to the present invention is configured so that the back surface of the insert comes into contact with the mold body when the mold is clamped and the back surface of the insert is detached from the mold body when the mold is opened. Thus, a predetermined space is formed between the back surface of the insert and the mold body. On the other hand, when the mold is clamped, the external heating means is retracted to a position where it does not interfere with the insert, and when the mold is opened, the external heating means advances to a position facing either the molding surface or the back surface of the insert to transfer the molding surface by heat transfer. Heat directly or indirectly through the back side. Furthermore, the cooling means provided in the mold body is brought into contact with the back surface of the insert during mold clamping, and the molding surface is cooled via the back surface.
[0007]
Claim 2 The mold heating / cooling device according to the invention is configured such that the back surface of the cavity insert is brought into contact with the mold body when the mold is clamped by the cavity insert moving means, and the back surface of the cavity insert is attached to the mold body when the mold is opened. A predetermined space is formed between the back surface and the mold body. Further, when the mold is clamped, the external heating means is retracted to a position where it does not interfere with the cavity insert, and when the mold is opened, the external heating means advances to a position where it abuts on the back surface of the cavity insert, and the cavity surface passes through the back surface by heat conduction. Heat. Furthermore, the cooling means provided in the mold body is brought into contact with the back surface of the cavity insert during mold clamping, and the cavity surface is cooled through the back surface.
[0008]
Claim 3 In the mold heating apparatus according to the invention, the cavity insert moving means makes the back surface of the cavity insert come into contact with the mold body when the mold is clamped, and the back surface of the cavity insert from the mold body when the mold is opened. A predetermined space is formed between the back surface and the mold body by separating. Further, the first external heating means is retracted to a position where it does not interfere with the cavity insert when the mold is clamped, and the first external heating means advances to a position where it abuts on the back surface of the cavity insert when the mold is opened. The cavity surface is heated. On the other hand, the second external heating means is retracted to a position where it does not interfere with the cavity insert when the mold is clamped, and at the time of opening the mold, the second external heating means advances to a position close to and opposed to the cavity surface of the cavity insert. The cavity surface is heated by radiation. Furthermore, the cooling means provided in the mold body is brought into contact with the back surface of the cavity insert during mold clamping, and the cavity surface is cooled through the back surface.
[0009]
Claim 4 The mold heating apparatus according to the invention is Claim 3 In this invention, the second external heating means is constituted by an electric discharge machining electrode obtained by machining the cavity surface of the cavity insert.
[0010]
Claim 5 The mold heating apparatus according to the invention is Claim 3 In the invention, the second external heating means includes a first heating surface that is closely opposed to the cavity surface of the cavity insert with a predetermined gap when the mold is opened, and extends to the first heating surface. It comprises a second heating surface that contacts the parting surface of the cavity insert and heats the cavity surface via the parting surface by heat conduction.
[0011]
Claim 6 The mold heating apparatus according to the invention is Claim 2 In the invention according to any one of claims 1 to 4, the thickness of at least the portion of the nest corresponding to the cavity surface is in the range of 0.5 mm to 15 mm.
[0012]
Claim 7 In the mold heating method according to the invention, with the mold opening, the back surface of the insert is separated from the mold body to form a predetermined space between the back surface and the mold body. Next, an external heating means as a heat source is advanced into the space, arranged opposite to the back surface of the nest, and the molding surface is heated via the back surface by heat transfer.
[0013]
Claim 8 In the mold heating and cooling method according to the present invention, the mold rear surface is separated from the mold body to form a predetermined space between the back surface and the mold body as the mold is opened. Next, an external heating means as a heat source is advanced into the space, arranged opposite to the back surface of the nest, and the molding surface is heated via the back surface by heat transfer. Thereafter, with mold clamping, the external heating means is retracted from the space, and the cooling means is brought into contact with the back surface of the nest, and the molding surface is cooled via the back surface.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
[0015]
FIG. 1 is an explanatory view showing the time of mold cooling by the mold heating / cooling device of the first embodiment of the present invention. FIG. 2 is an explanatory view showing the time when the mold is heated by the mold heating / cooling device according to the first embodiment of the present invention. FIG. 3 is a sectional view showing a heating state by the heating means of the heating / cooling device for the mold according to the first embodiment of the present invention. FIG. 4 is an enlarged cross-sectional view showing a main part of the heating means of the mold heating / cooling device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view showing a cooling state by the cooling means of the mold heating / cooling device of the first embodiment of the present invention.
[0016]
Since the heating / cooling device of this embodiment is embodied in an injection mold, first, an outline of the structure of the injection mold will be described.
[0017]
1 and 2, the injection mold according to the present embodiment has a movable main mold 14 attached to a movable die plate 11 via a movable attachment plate 12 and a spacer block 13. On the right side surface of the movable main mold 14, a core surface 14 a having a convex cross section protruding rightward is formed, and the core surface 14 a constitutes a part (inner side surface portion) of the molding space S. An extrusion pin 16 is fixed to the space in the spacer block 13 so as to protrude rightward through an extrusion plate 15. The extrusion pin 16 is flush with the core surface 14a of the movable main mold 14 at the mold clamping position shown in FIG. Further, at the mold opening position shown in FIG. 2, the push plate 15 is moved rightward by the drive shaft 17 of the drive mechanism, and the tip surface of the push pin 16 protrudes rightward from the core surface 14 a of the movable main die 14. The molded product after cooling and solidification can be easily taken out. On the other hand, a fixed back plate 23 is fixed to the fixed side die plate 21 via a fixed side mounting plate 22. An introduction recess 23a for introducing the injection nozzle 24 is formed at the center of the right side surface of the fixed back plate 23, and the center of the fixed side mounting plate 22 and the fixed side die plate 21 communicates with the introduction recess 23a. Introducing holes 22a and 21a are respectively formed. A sprue 23b and a runner 23c are formed in the center of the introduction recess 23a of the fixed back plate 23, and the tip of the injection nozzle 24 is connected to the sprue 23b through the introduction holes 21a and 22a and the introduction recess 23a. It comes to wear. In addition, since the above structure is the same as that of a general injection mold, the detailed description of a relevant part is abbreviate | omitted.
[0018]
The fixed back plate 23 is a cooling section 23d having a convex cross section projecting leftward from the center of the left side surface. A plurality of cooling holes 23e are provided on the right side of the cooling portion 23d of the fixed back plate 23 in the front-rear direction (a direction orthogonal to the paper surface in FIGS. 1 and 2), and cooling fluid such as cooling water is supplied to the cooling holes 23e. By circulating, the temperature of the cooling part 23d is lowered. A fixed main mold 24 is attached to the left side surface of the fixed back plate 23 so as to be movable left and right. A fixed main mold moving mechanism (not shown) allows the mold clamping position shown in FIG. 1 and the mold opening position shown in FIG. It is designed to reciprocate between the two. A cavity insert 26 is fitted and fixed to the central portion of the fixed main mold 24 via a heat insulating plate 25.
[0019]
As shown in FIG. 3, the cavity insert 26 has a cavity surface 26a that forms the other part (outer surface portion) of the molding space S, and a back surface 26b that is located on the opposite side of the cavity surface 26a. The left side surface 26d of the cavity insert 26, the left side surface 24a of the fixed main mold 24, and the left side surface 25a of the heat insulating plate 25 are flush with each other to form a parting surface or a parting line PL. Further, the right side surface 24b of the fixed main mold 24 and the right side surface 25b of the heat insulating plate 25 are flush with each other, and a receiving hole having a shape in which the cooling portion 23d of the fixed back plate 23 is closely fitted in the center of the heat insulating plate 25. 25 c is formed, and a step-shaped recess is formed between the right side surface 25 b of the heat insulating plate 25 and the back surface 26 b of the cavity insert 26. Then, as shown in FIG. 5, in the mold clamping state, the cooling portion 23d is tightly fitted in the receiving hole 25c, the cooling portion 23d is in close contact with the back surface 26b of the cavity insert 26, and the right side of the fixed main die 24 The surface 24 b is in close contact with the left side surface 23 f of the fixed back plate 23. Further, in the mold clamping state, the left side surfaces 24 a, 25 a, and 26 d of the fixed main mold 24, the heat insulating plate 25, and the cavity insert 26 are in close contact with the right side face of the movable main mold 14. A molding space S having a substantially U-shaped cross section is formed between the cavity surface 26 a and the core surface 14 a of the movable main mold 14. In addition, a gate 26c is formed in the center of the cavity insert 26 so as to align and communicate with the runner 23c of the fixed back plate 23.
[0020]
The fixed main mold 24, the heat insulating plate 25, and a fixed main mold moving mechanism (not shown) constitute a cavity insert moving means for reciprocating the cavity insert 26 in the left-right direction. The back surface 26b is brought into contact with the left side surface 23f of the fixed back plate 23 as a mold body, and when the mold is opened, the back surface 26b of the cavity insert 26 is separated from the left side surface 23f of the fixed back plate 23 and the back surface 26b. A space with a predetermined interval is formed between the fixed back plate 23 and the fixed back plate 23. Further, by a cooling portion 23d and a cooling hole 23e provided on the fixed back plate 23 as the mold body, the cavity surface 26a is brought into contact with the back surface 26b of the cavity insert 26 at the time of clamping, and the cavity surface 26a is interposed through the back surface 26b. A cooling means for cooling is configured. As in the case of a general injection mold, the fixed main mold 24 is supported on the fixed back plate 23 via the guide pins 27, and the fixed main mold 24 and the movable main mold 14 are moved left and right via the guide pins 27. It is guided and aligned with the exact clamping position.
[0021]
Next, the external heating means of this embodiment will be described.
[0022]
As shown in FIG. 3, the present embodiment includes first and second external heating means 31 and 32 having a substantially square block shape corresponding to the cavity surface 26a as external heating means. The first external heating means 31 is retracted by the first moving mechanism 41 to a retracted position (position in FIG. 1) that does not interfere with the cavity insert 26 when the mold is clamped, and the cavity insert 26 when the mold is opened. The cavity surface 26a is heated through the back surface 26b by heat conduction by advancing to a heating position (position shown in FIG. 2) in close contact with the back surface 26b of the surface. Note that the width and height (front and rear dimensions and vertical dimension in the figure) of the first external heating means 31 are set to be smaller than the width and height of the accommodation holes 25c of the heat insulating plate 25 by a predetermined value, respectively. The front and back and upper and lower side surfaces of the heating means 31 are in contact with the heat insulating plate 25 to prevent the heat insulating plate 25 from being directly heated. The dimension of the first external heating means 31 is set so that at least substantially the entire back surface 26b corresponding to the cavity surface 26a can be heated, and the dimension of the accommodation hole 25c of the heat insulating plate 25 is set correspondingly.
[0023]
Here, the thickness of the cavity insert 26 is preferably set to 15 mm or less at least in the portion corresponding to the cavity surface 26a in order to improve heat conduction from the back surface 26b side. In particular, it is more preferable to set the thickness of the cavity insert 26 at the portion where the first external heating means 31 abuts within this range. If the thickness exceeds 15 mm, the heat conduction efficiency is lowered, and the heat transfer time from the back surface 26b side of the cavity insert 26 to the cavity surface 26a side may be increased. On the other hand, such a thickness is preferably 0.5 mm or more when the cavity insert 26 is processed by cutting. If the thickness is less than 0.5 mm, the cavity insert 26 may be difficult to cut or the workability may be reduced. When the cavity insert 26 can be processed to be thinner by a processing method other than cutting, the lower limit value may be set to about 0.2 mm, for example. However, when the lower limit is less than 0.2 mm, the cavity insert 26 may be thermally deformed during heating or may be damaged by the injection pressure of the resin.
[0024]
The second external heating means 32 is retracted by the second moving mechanism 42 to a retracted position (position shown in FIG. 1) that does not interfere with the cavity insert 26 when the mold is clamped, and the cavity insert when the mold is opened. The cavity surface 26a is advanced to a heating position (position shown in FIG. 2) that faces and opposes the cavity surface 26a with predetermined gaps d1, d2, and d3, and the cavity surface 26a is heated by heat radiation. The width and height (front and rear dimensions and vertical dimension in the figure) of the second external heating means 32 are set smaller than the width and height of the cavity surface 26a of the cavity insert 26 by a predetermined value, respectively. The front and rear and upper and lower side surfaces of the heating means 32 abut against the cavity insert 26 to prevent the cavity insert 26 from being directly heated. The gaps d1, d2, d3 between the second external heating means 32 and the cavity surface 26a are desirably made as small as possible to increase the heat radiation efficiency, and preferably about 0.2 mm. If the gap is less than 0.2 mm, it may be difficult to secure a constant gap between the second external heating unit 32 and the cavity surface 26a. May come into contact with the cavity surface 26a and cause damage.
[0025]
Next, the detail of a structure of the 1st and 2nd external heating means 31 and 32 is demonstrated. Since the first external heating unit has the same configuration as that of the second external heating unit, the same reference numerals are assigned to the corresponding portions, and redundant description is omitted here.
[0026]
As shown in FIG. 4, the first and second external heating means 31 and 32 are formed on the flat plate-like support plates 31a and 32a via the plate-like heat sources 31b and 32b, and the plate-like heat plates 31c and 32c. It has a three-layered square block shape. The support plates 31a, 32a are located on the first or second moving mechanism 41, 42 side, and preferably to prevent the influence of heat transfer to the first or second moving mechanism 41, 42, It is made of a heat insulating material. The heat sources 31b and 32b may be any heat sources that can heat the hot plates 31c and 32c to a desired temperature, for example, near 350 ° C. within a predetermined time, corresponding to the melting temperature of the injection resin. A known electric heater may be incorporated in the metal, or a heating fluid such as hot oil may be circulated. Further, the hot plates 31c and 32c are formed of a metal having a good thermal conductivity such as a copper plate. In the present embodiment, as the hot plate 32c of the second external heating means 32, an electric discharge machining electrode obtained by machining the cavity surface 26a of the cavity insert 26 is used, and the gaps d1, d2 between the hot plate 32c and the cavity surface 26a are used. , D3 are easily maintained at a constant value. As the first and second moving mechanisms 41, 42, various known two-dimensional or three-dimensional moving mechanisms such as two-dimensional or three-dimensional combinations of hydraulic cylinders may be employed. Can do.
[0027]
Next, an injection molding operation using the mold heating and cooling method by the mold heating and cooling apparatus of the present embodiment configured as described above will be described. The injection molding operation is performed according to a control program stored in advance in the ROM by using a control unit including a CPU, a ROM, a RAM, and the like. FIG. 6 is a process diagram showing a mold heating and cooling method according to the first embodiment of the present invention.
[0028]
First, in a mold opening process as a space forming process, a mold clamping device (not shown) of an injection molding machine is driven, and a movable main mold 14 is moved via a movable die plate 11, a movable attachment plate 12, and a spacer block 13. Is moved to the left, and a sufficient space is provided between the fixed main mold 24 and the fixed back plate 23 as the mold opening position of FIG. At the same time, the fixed main mold 24 is moved to the left by the fixed main mold moving mechanism, the back surface 26b of the cavity insert 26 is separated from the fixed back plate 23, and between the movable main mold 14 and the fixed back plate 23. It is arranged at a substantially middle position. As a result, as shown in FIG. 2, predetermined intervals are provided between the fixed back plate 23 and the back surface 26b of the cavity insert 26, and between the cavity surface 26a of the cavity insert 26 and the movable main mold 14, respectively. A space is formed.
[0029]
Next, in the hot plate approaching process, the first moving mechanism 41 is driven to advance the first external heating means 31 having the heat source 31b into the space between the fixed back plate 23 and the fixed main mold 24. The hot plate 31 c is disposed opposite to the back surface 26 b of the cavity insert 26. At the same time, the second moving mechanism 42 is driven, the second external heating means 32 having the heat source 32b is advanced into the space between the fixed main mold 24 and the movable main mold 14, and the hot plate 32c is moved into the cavity. The insert 26 is disposed opposite to the cavity surface 26a.
[0030]
2 and 3, in the heating process, the first and second moving mechanisms 41 and 42 bring the hot plate 31c of the first external heating means 31 into close contact with the back surface 26b of the cavity insert 26. At the same time, the hot plate 32c of the second external heating means 32 is placed close to the cavity surface 26a with predetermined gaps d1, d2, d3. Then, the hot plate 31c of the first external heating means 31 heats the back surface 26b of the cavity insert 26 by heat conduction, and indirectly heats the cavity surface 26a as a molding surface from the back surface 26b side. At the same time, the hot plate 32c of the second external heating means 32 directly heats the cavity surface 26a of the cavity insert 26 by heat radiation. The heating time in this heating step is the thickness of the portion corresponding to the cavity surface 26a of the cavity insert 26 to be heated, the target heating value of the cavity surface 26a according to the type of injection resin, and the heating temperature of the hot plates 31c and 32c. It changes suitably according to etc. For example, when the ABS resin is injected, the thickness of the portion corresponding to the cavity surface 26a of the cavity insert 26 is 10 mm, and the target temperature of the cavity surface 26a is 130 ° C., the heating temperature of the hot plates 31c and 32c is about 350. When it is set to ° C., the heating time is about 30 to 40 seconds. In addition, when the thickness of the portion corresponding to the cavity surface 26a of the cavity insert 26 is changed to 5 mm under such conditions, the cavity surface 26a can be brought to the same temperature as the above temperature with a heating time of 20 seconds or less. In this case, if the heating time is 1 minute, the temperature of the cavity surface 26a can be about 200 ° C. At this time, the heat insulating plate 25 prevents the cavity insert 26 from radiating heat. In addition, since the hot plate 32c of the second external heating means 32 is constituted by the electric discharge machining electrode, the gap with the cavity surface 26a can be set to an extremely small and uniform interval of 0.2 mm, and the heat radiation can be reduced. It can be performed efficiently and can be prevented from being damaged by contact. Furthermore, since the cavity insert 26 is made as thin as possible, heat conduction from the back surface 26b side can be performed efficiently. The temperature of the cavity surface 26a itself is determined according to the type of resin, the heating deformation temperature, etc., as in the normal mold temperature adjustment technique.
[0031]
Thereafter, in the hot plate separation step, the first moving mechanism 41 separates the hot plate 31c of the first external heating means 31 from the position where it contacts the back surface 26b of the cavity insert 26, and the cavity insert 26 and the fixed back are fixed. Retreat from the space between the plate 24 to the retreat position of FIG. At the same time, the second moving mechanism 42 separates the hot plate 32c of the second external heating means 32 from a position approaching the cavity surface 26a of the cavity insert 26, and the cavity insert 26 and the movable main mold 14 are separated from each other. Retreat from the space between them to the retreat position of FIG.
[0032]
Thereafter, in the mold clamping process, the fixed main mold moving mechanism is driven to clamp the fixed main mold 24 to the fixed back plate 23 and the mold clamping device is driven to move the movable side die plate 11 and the movable side attachment. The movable main mold 14 is clamped to the fixed main mold 24 and the fixed back plate 23 via the plate 12 and the spacer block 13. Then, the movable main mold 14 and the cavity insert 26 are clamped at the parting surface, and a molding space S having the same shape as the molded product shape is formed between the core surface 14a and the cavity surface 26a, and the fixed back plate. 23 sprues 23 b and runners 23 c communicate with the gate 26 c of the cavity insert 26. At the same time, the cooling portion 23 d of the fixed back plate 23 is in close contact with the back surface 26 b of the cavity insert 26. In this state, by pressing the tip of the injection nozzle 24 against the sprue 23b, the molten resin can be injected and injected from the injection nozzle 24 into the molding space S through the sprue 23b, the runner 23c, and the gate 26c.
[0033]
Then, in the injection process of the injection cooling process, molten resin is injected and injected into the sprue 23b from the injection device (not shown) through the injection nozzle 24, and between the cavity surface 26a and the core surface 14a from the gate 26c through the runner 23c. The molding space S to be formed is filled with molten resin. At this time, since the cavity surface 26a is heated to a desired temperature, the molten resin in contact with the cavity surface 26a reliably maintains the heat deformation temperature (for example, 160 ° C. to 170 ° C. in the case of ABS resin), and the flow mark, Generation | occurrence | production of a silver streak (silver stripe) etc. can be prevented reliably. Further, since the cooling portion 23d of the fixed back plate 23 is in close contact with the back surface 26b of the cavity insert 26 at the time of injection, a large amount of cooling fluid such as cooling water is supplied and distributed to the cooling holes 23e of the fixed back plate 23. By doing so, the back surface 26b of the cavity insert 26 can be instantaneously cooled by the cooling portion 23d as a cooling means, and the cavity surface 26a can be rapidly cooled by heat conduction, thereby sufficiently promoting the cooling and solidification of the molten resin. be able to. At this time, since the cavity insert 26 is made as thin as possible, the cooling efficiency can be improved. As a result, the injection resin becomes the heat deformation temperature or lower and quickly cools and solidifies, and a molded product having a predetermined shape corresponding to the molding space S is quickly molded. It should be noted that the temperature gradient of the cavity surface 26a from the injection of the molten resin to the cooling and solidification can be appropriately adjusted by the initial set heating temperature of the cavity surface 26a and the set cooling temperature of the cooling unit 23d.
[0034]
Thereafter, in the mold opening process shown in FIG. 3, the mold clamping device is driven to open the movable main mold 14 away from the fixed main mold 24. As a result, the core surface 14a and the cavity surface 26a are opened, and the molded product is released from the cavity surface 26a and remains on the core surface 14a. Thereafter, in the product take-out step, an extrusion driving means (not shown) is driven, the push pin 16 protrudes from the core surface 14a, and the molded product is pushed out from the core surface 14a to be removed, thereby taking out the product.
[0035]
Thereafter, the above series of steps can be repeated to continuously obtain a resin molded product having a desired shape.
[0036]
As described above, the mold heating and cooling device of the above embodiment is connected to the cavity insert 26 having the cavity surface 26a that forms a part of the molding space S and the back surface 26b that is located on the opposite side of the cavity surface 26a. When the mold is clamped, the back surface 26b of the cavity insert 26 is brought into contact with the fixed back plate 23 as a mold body, and when the mold is opened, the back surface 26b of the cavity insert 26 is detached from the fixed back plate 23 and Clamping is performed by a fixed main mold 24, a heat insulating plate 25, a fixed main mold moving mechanism as a cavity nest moving means 24 that forms a predetermined space between the back surface 26 b and the fixed back plate 23, and a first moving mechanism 41. At the time of retreating to a position where it does not interfere with the cavity insert 26, when the mold is opened, it advances to a position where it abuts against the back surface 26b of the cavity insert 26, and heat transfer from the hot plate 31c. The first external heating means 31 that heats the cavity surface 26a via the back surface 26b and the second moving mechanism 42 are used to retract to a position that does not interfere with the cavity insert 26 during mold clamping, and When opened, a second external portion having a hot plate 32c that advances to a position facing and close to the cavity surface 26a of the cavity insert 26 with a predetermined gap and heats the cavity surface 26 by heat radiation from the hot plate 32c. A cooling unit 23d and a cooling hole, which are provided on the heating unit 32 and the fixed back plate 23, abut against the back surface 26b of the cavity insert 26 during mold clamping, and cool the cavity surface 26a via the back surface 26b. 23e.
[0037]
Therefore, in the above embodiment, when the mold is heated, the cooling portion 23d is separated from the cavity insert 26 and does not cool the cavity insert 26. Therefore, the first and second external heating means 31 and 32 are used. The cavity insert 26 can be heated efficiently and quickly. Further, when the mold is cooled, the first and second external heating means 31 and 32 are retracted from the cavity insert 26 and the cavity insert 26 is not heated. Cooling can be performed efficiently and quickly, and the cooling and solidification rate of the resin can be increased. As a result, the heating performance and the cooling performance can be improved, respectively, and the molding cycle from the resin injection after heating the mold to the solidification and removal of the resin accompanying the cooling of the mold can be greatly shortened. In addition, since the first and second external heating means 31 and 32 and the cooling unit 23d operate independently in a thermally separated form, the optimum temperature of the cavity surface 26a is determined according to the type of the injection resin and the like. A thermal gradient can be obtained easily and quickly, and product quality can be improved. That is, in the case of heating with a heater built in the mold or a heating source such as hot water or hot oil as in the prior art, the temperature of the heating source itself is not easily lowered, and the thermal responsiveness during cooling was not sufficient. In this embodiment, since the first and second external heating means 31 and 32 as the heating source are retracted to a position spatially separated from the mold, the thermal response in the case where the mold is the heating source or the like. The sex can be increased. Then, by increasing the mold temperature at the start of resin material emphasis, the appearance of the molded product is improved, and the mold temperature is lowered by the heat removal action by the cooling part 23d that starts immediately after mold clamping. The molding cycle required until product removal can be shortened. In other words, the apparatus of the present embodiment can produce a high-quality molded product with a high molding cycle by enabling a large change in mold temperature.
[0038]
The heating means is not a type with a built-in mold, but a type arranged outside the mold, such as the first and second external heating means 31, 32, while the heat source 31b, 32b itself is used. Since a known heat source having a relatively simple configuration, such as an electric heater, can be used, the equipment cost is greatly reduced as compared with the case where an expensive or complicated configuration such as high-frequency induction heating or SSI molding is used. In addition, it is easy to maintain and improve maintainability. Furthermore, since the second external heating means 32 does not directly contact the cavity surface 26a that determines the surface quality of the molded product, it is possible to prevent quality deterioration such as scratches and metal burns due to thermal oxidation, and the product itself. The quality of the can be maintained well.
[0039]
Further, by setting the thickness of the cavity insert 26 to a range of about 0.5 mm to 15 mm at least at the portion corresponding to the cavity face 26 a, the heating of the cavity face 26 a from the back face 26 b side of the cavity insert 26 can be performed more efficiently. This can be done quickly, and the temperature rise of the cavity surface 26a can be further increased. The heating efficiency by heat radiation from the second external heating means 32 is reduced by reducing the gaps d1, d2, d3 between the hot plate 32c of the second external heating means 32 and the cavity surface 26a to about 0.2 mm. Can be increased. As a result, the heating time of the cavity surface 26a can be further shortened, and the entire molding cycle can be further shortened. Furthermore, since the hot plate 31c of the first external heating means 31 is in direct contact with the back surface 26b of the cavity insert 26 that does not affect the quality of the molded product, the quality of the molded product is maintained well, while the cavity surface is maintained. The heating of 26a can be performed more efficiently.
[0040]
Further, since the cavity insert 26 is attached to the fixed main mold 24 via the heat insulating plate 25, the heat stored in the cavity insert 26 can be prevented from being dissipated by the heat insulating plate 25. Further, the heat dissipation from the first and second external heating means 31 and 32 is effectively prevented by configuring the support plates 31a and 32a of the first and second external heating means 31 and 32 with a heat insulating material. In addition, the influence of heat conduction on the first and second moving mechanisms 41 and 42 can be prevented.
[0041]
Next, a second embodiment according to the present invention will be described below. In the present embodiment, only differences from the first embodiment will be described, and the same components as those in the first embodiment will be denoted by the same reference numerals and description thereof will be omitted.
[0042]
FIG. 7 is a cross-sectional view showing a heating state by the heating means of the mold heating / cooling device of the second embodiment of the present invention.
[0043]
In the present embodiment, the shape of the portion corresponding to the hot plate of the second external heating means 51 is different from that of the first embodiment, and other configurations are the same as those of the first embodiment. That is, at least the portion corresponding to the hot plate of the second external heating means 51 is arranged so as to be opposed to the first heating surface 51a facing the cavity surface 26a of the cavity insert 26 with a predetermined gap when the mold is opened. The second heating is extended to the heating surface 51a and contacts the parting surface formed by the left side surface 26d of the cavity insert 26 when the mold is opened, and heats the cavity surface 26a through the parting surface by heat conduction. It has a surface 51b. Similar to the hot plate 32c of the second external heating means 32 of the first embodiment, the first heating surface 51a has a predetermined small gap between it and the cavity surface 26a by thermal radiation. Heat.
[0044]
In the present embodiment, in addition to the same operations and effects as the first embodiment, the cavity surface 26a can be heated more efficiently and in a short time by the second external heating means 51 from the cavity surface 26a side. There is an effect that can be done.
[0045]
By the way, although each said embodiment was concretely demonstrated to the heating-and-cooling apparatus and method of a metal mold | die, when implementing this invention, at least a cavity nest moving means and the 1st or 2nd external heating means You may actualize in the heating apparatus of the metal mold | die which consists of 31,32,51. In addition to the injection mold, the mold may be embodied as one in which preheating of the cavity surface is considered effective.
[0046]
Further, as in each of the above embodiments, the first or second external heating means 31 and 32 is not a three-layer structure of the support plates 31a and 32a, the heat sources 31b and 32b, and the heat plates 31c and 32c. Other configurations such as a built-in single layer structure may be used. In this case, in the second external heating means 51 of the second embodiment, at least a hot plate portion is constituted by the first and second heating surfaces 51a and 51b.
[0047]
In each of the above embodiments, the predetermined gaps d1, d2, and d3 are provided between the second external heating means 32 and 51 and the cavity surface 26a. However, the hot plate 32c is made of a copper plate or the like and is harder than the cavity insert 26. In the case of forming with a low material, the second external heating means 32, 51 can be brought into contact with the cavity surface 26a and heated by direct heat conduction. However, in the case of a mold in which a texture pattern is provided on the cavity surface 26a, it is necessary to provide a predetermined gap between the second external heating means 32 and 51 and the cavity surface 26a.
[0048]
Furthermore, in this apparatus and method, at least one of the core surface 14a and the cavity surface 26a forming the molding space S is preheated before injection by the external heating means in a state of being thermally separated from the cooling means. For example, the core surface may be provided on the core insert, and at least one of the core surface and the back surface of the core insert may be heated by an external heating means instead of the cavity surface. In this case, the shape of the hot plate of the external heating means corresponds to the core surface shape and the back surface shape of the core insert. In contrast to the above embodiments, the core surface may be provided not on the movable main mold side but on the fixed main mold side, and the cavity surface may be provided on the movable main mold side. The cooling means is not limited to that of the above embodiment, and other cooling means can be employed.
[0049]
In the present specification, the “mold body” refers to a mold part adjacent to and in contact with the cavity insert 26 or the core insert, and in the above embodiment, the fixed back plate 23. . When the core surface is provided in the core insert and the core insert is heated, the movable back plate adjacent to the core insert becomes the mold body.
[0050]
【The invention's effect】
As above Claim 1 In the mold heating apparatus according to the invention, the back surface of the insert is spatially separated from the mold body provided with the cooling means, and is thermally insulated from the mold, and the forming surface of the insert is externally heated. Therefore, the heating efficiency is improved. Moreover, since the molding surface is heated from the back surface side, it is possible to prevent the possibility of scratches on the molding surface, metal burns due to thermal oxidation, and the like. Furthermore, when the insert is cooled, the external heating means is spatially separated from the mold body, and the molding surface of the insert can be cooled in a state of being substantially thermally insulated, so that the cooling efficiency is improved. . As a result, the mold temperature can be greatly changed, and a high-quality molded product can be produced in a short molding cycle.
[0051]
Claim 2 The mold heating and cooling device according to the invention is such that the back surface of the cavity insert is spatially separated from the mold body provided with the cooling means and is thermally insulated substantially, and the cavity insert by the external heating means. Since the molding surface can be heated, the heating efficiency is improved. Moreover, since the molding surface is heated from the back surface side, it is possible to prevent the possibility of scratches on the molding surface, metal burns due to thermal oxidation, and the like. Furthermore, when cooling the cavity insert, the external heating means is spatially separated from the mold body, and the molding surface of the cavity insert can be cooled in a state of being substantially thermally insulated. improves. As a result, the mold temperature can be greatly changed, and a high-quality molded product can be produced in a short molding cycle.
[0052]
Claim 3 In the mold heating and cooling device according to the invention, the back surface of the cavity insert is spatially separated from the mold body provided with the cooling means, and is thermally insulated from the first and second external parts. Since the heating surface of the cavity insert can be heated by the heating means, the heating efficiency is improved. In addition, the first external heating means is directly brought into contact with the back surface of the cavity insert to indirectly heat the molding surface by heat conduction, thereby preventing the possibility of scratching the molding surface, metal burning due to heat oxidation, etc. And heating efficiency can be raised further. On the other hand, since the second external heating means directly heats the cavity surface by thermal radiation, it is possible to prevent the possibility of scratches on the molding surface, metal burning due to thermal oxidation, and the like, and further increase the heating efficiency. Further, when the cavity insert is cooled, the molding surface of the cavity insert may be cooled in a state where the first and second external heating means are spatially separated from the mold body and thermally insulated. This improves the cooling efficiency. As a result, the mold temperature can be greatly changed, and a high-quality molded product can be produced in a short molding cycle.
[0053]
Claim 4 The mold heating and cooling device according to the invention is Claim 3 In addition to the invention described above, special processing that is normally performed to make the second external heating means correspond to the cavity surface shape is not required, and the cost of parts can be reduced, and a predetermined distance between the second external heating means and the cavity surface can be reduced. The gap can be easily and accurately provided.
[0054]
Claim 5 The mold heating and cooling device according to the invention is Claim 3 In addition to the invention described above, the second heating surface of the second external heating means directly contacts the parting surface of the cavity insert, and efficiently heats the nearest cavity surface by heat conduction. Further, the first heating surface efficiently heats the cavity surface by heat radiation. As a result, the molding cycle can be further shortened.
[0055]
Claim 6 The mold heating and cooling device according to the invention is Claim 2 In addition to the invention described in any one of Items 4 to 4, since the thickness of the cavity nest is sufficiently small, the heat conduction heating from the back side of the cavity nest by the first external heating means can be performed more efficiently. it can.
[0056]
Claim 7 The mold heating method according to the invention is such that the back surface of the insert is spatially separated from the mold main body and is thermally insulated, and the forming surface of the insert is heated by the external heating means. Therefore, the heating efficiency is improved. As a result, the mold temperature can be greatly changed, and a high-quality molded product can be produced in a short molding cycle.
[0057]
Claim 8 In the mold heating and cooling method according to the invention, the back surface of the insert is spatially separated from the mold body provided with the cooling means, and the insert is molded by the external heating means in a state of being substantially thermally insulated. Since the surface can be heated, the heating efficiency is improved. Moreover, since the molding surface is heated from the back surface side, it is possible to prevent the possibility of scratches on the molding surface, metal burns due to thermal oxidation, and the like. Furthermore, when cooling the insert, the external heating means is spatially separated from the mold body, and the molded surface of the insert can be cooled in a state of being substantially thermally insulated, thereby improving the cooling efficiency. To do. As a result, the mold temperature can be greatly changed, and a high-quality molded product can be produced in a short molding cycle.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an explanatory diagram showing when a mold is cooled by a mold heating / cooling device according to a first embodiment of the present invention.
FIG. 2 is an explanatory diagram showing heating of a mold by a mold heating / cooling device according to the first embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a heating state by a heating means of the heating / cooling device for the mold according to the first embodiment of the present invention.
FIG. 4 is an enlarged cross-sectional view showing a main part of a heating means of the heating / cooling device for a mold according to the first embodiment of the present invention.
FIG. 5 is a cross-sectional view showing a cooling state by the cooling means of the heating / cooling device for the mold according to the first embodiment of the present invention.
FIG. 6 is a process diagram showing a mold heating and cooling method according to the first embodiment of the present invention.
FIG. 7 is a sectional view showing a heating state by a heating means of a heating / cooling device for a mold according to a second embodiment of the present invention.
[Explanation of symbols]
14a Core surface (molded surface)
23 Fixed back plate (mold body)
23d Cooling unit (cooling means)
23e Cooling hole (cooling means)
24 Fixed main mold (nesting movement means, cavity nesting movement means)
25 Insulation plate (nesting movement means, cavity nesting movement means)
26 Cavity nested (nested)
26a Cavity surface (molding surface)
31 First external heating means (external heating means)
32 Second external heating means (external heating means)
51 Second external heating means (external heating means)
51a First heating surface
51b Second heating surface
S Molding space

Claims

Connected to a nest having a molding surface forming a molding space and a back surface opposite to the molding surface, the back surface of the nest is brought into contact with the mold body during mold clamping, and the nest is opened when the mold is opened. Nesting moving means for separating the back surface of the mold body from the mold body and forming a predetermined space between the back surface and the mold body;
Retreating to a position that does not interfere with the insert during mold clamping, and external heating means for heating the molding surface through the back surface by advancing to a position facing the back of the insert during mold opening ,
A mold heating / cooling device, comprising: a cooling unit that is provided in the mold body, abuts against a back surface of the insert during mold clamping, and cools the molding surface through the back surface.

It is connected to a cavity insert having a cavity surface that forms a part of the molding space and a back surface located on the opposite side of the cavity surface. At the time of clamping, the back surface of the cavity insert is brought into contact with the mold body. Cavity nesting moving means for separating the back surface of the cavity nesting from the mold body at the time of opening and forming a predetermined space between the back surface and the mold body,
When the mold is clamped, it is retracted to a position where it does not interfere with the cavity insert, and when the mold is opened, it advances to a position that contacts the back surface of the cavity insert and heats the cavity surface via the back surface by heat conduction. Means,
A mold heating / cooling apparatus, comprising: a cooling unit provided in the mold body, contacting a back surface of the cavity insert during mold clamping, and cooling the cavity surface through the back surface.

It is connected to a cavity insert having a cavity surface that forms a part of the molding space and a back surface located on the opposite side of the cavity surface. At the time of clamping, the back surface of the cavity insert is brought into contact with the mold body. Cavity nesting moving means for separating the back surface of the cavity nesting from the mold body at the time of opening and forming a predetermined space between the back surface and the mold body,
The mold is retracted to a position that does not interfere with the cavity insert during mold clamping, and is advanced to a position that contacts the back surface of the cavity insert when the mold is opened to heat the cavity surface through the back surface by heat conduction. External heating means,
When the mold is clamped, it is retracted to a position where it does not interfere with the cavity insert, and when the mold is opened, the cavity face is advanced to a position close to and opposed to the cavity face of the cavity insert with a predetermined gap to heat the cavity face by heat radiation. A second external heating means;
A mold heating / cooling apparatus, comprising: a cooling unit provided in the mold body, contacting a back surface of the cavity insert during mold clamping, and cooling the cavity surface through the back surface.

4. The mold heating / cooling device according to claim 3, wherein the second external heating means includes an electric discharge machining electrode obtained by machining a cavity surface of the cavity nest.

The second external heating means includes a first heating surface that faces and opposes the cavity surface of the cavity insert with a predetermined gap when the mold is opened, and extends to the first heating surface. 4. The mold heating / cooling device according to claim 3, further comprising a second heating surface that contacts the parting surface of the cavity insert and heats the cavity surface via the parting surface by heat conduction. .

The mold heating / cooling device according to any one of claims 2 to 4, wherein a thickness of at least a portion corresponding to the cavity surface of the insert is in a range of 0.5 mm to 15 mm.

In a heating method of a mold for heating an insert having a molding surface forming a molding space and a back surface located on the opposite side of the molding surface before injection molding,
A space forming step of forming a predetermined space between the back surface and the mold body by separating the back surface of the insert from the mold body along with the mold opening,
And a heating step of extending an external heating means having a heat source into the space, facing the back surface of the insert and heating the molding surface through the back surface by heat transfer. Mold heating method.

In a heating method of a mold for heating an insert having a molding surface forming a molding space and a back surface located on the opposite side of the molding surface before injection molding,
A space forming step of forming a predetermined space between the back surface and the mold body by separating the back surface of the insert from the mold body along with the mold opening,
An external heating means having a heat source is advanced into the space, and the heating step of heating the molding surface through the back surface by heat transfer by disposing it opposite to the back surface of the insert,
A cooling step of retracting the external heating means from the space with mold clamping, contacting a cooling means against the back surface of the insert, and cooling the molding surface through the back surface. Mold heating method.