JP3608212B2

JP3608212B2 - How to prevent flash

Info

Publication number: JP3608212B2
Application number: JP33329893A
Authority: JP
Inventors: 武広仙石; 治水野; 正人江島
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 1993-12-27
Filing date: 1993-12-27
Publication date: 2005-01-05
Anticipated expiration: 2020-01-05
Also published as: JPH07186197A

Description

【０００１】
【産業上の利用分野】
本発明は、ばり発生防止方法、詳しくは、型締め時に、成形部形成用キャビティから伸びる隙間が生じる金型において、この隙間に発生するばりを防止するばり発生防止方法に関する。
【０００２】
【従来の技術】
例えば、金具をインサートして樹脂成形品を射出成形する金型においては、図８に示すように、型締め時に、インサート金具１の周面と金型８の一面との間に隙間１２が生じ、樹脂流し込み時に、この隙間１２に樹脂材料１５が侵入し、型開き後取り出される樹脂成形品にばり１６が一体に付いているという不具合がある。
【０００３】
この隙間１２は、インサート金具１の寸法精度又は成形方法によって小さくすることは可能であるが、インサート金具１の寸法精度の向上には限度が有ることから、この隙間１２をばり１６の発生を無くすまで小さくすることはきわめて困難であった。また、成形方法によってばり１６の発生を防止することが可能であるが、従来は、作業者の経験と勘に頼っており、ばり１６の発生を常に防止することは困難であった。
【０００４】
特開平４−１８２１０５号公報には、ばりを厚く形成することにより、ばり取りを容易にする金型構造が開示されている。
【０００５】
【発明が解決しようとする課題】
しかし、上記従来技術には、ばり発生位置にランナ等を配置する必要があることから、適用可能な成形品形状に制約があり、また、金型構造が複雑になるなどの問題がある。
【０００６】
本発明は、上記問題点を解決し、適用可能な成形品形状の範囲の拡大及び金型構造の簡単化を図りつつばりの発生を防止できるばり発生防止方法を提供することを目的とする。
【０００７】
【課題を解決するための手段】
本発明に係る第１のばり発生防止方法は、型締め時に、成形部形成用キャビティから伸びる隙間が生じる金型におけるばり発生防止方法であって、ゲートを介して前記成形部形成用キャビティに流し込まれた樹脂材料が前記隙間に到達して固化し、その後、前記成形部形成用キャビティが前記樹脂材料で完全充填されるよう、前記ゲートの位置を設定したことを特徴とする。
【０００８】
また、本発明に係る第２のばり発生防止方法は、型締め時に、成形部形成用キャビティから伸びる隙間が生じる金型におけるばり発生防止方法であって、前記隙間を形成する金型端面における前記成形部形成用キャビティ寄りの部位に、前記成形部形成用キャビティから前記隙間に向かって縮径するテーパ面からなる、ばりのばらつきを吸収するための凹部を形成したことを特徴とする。
【０００９】
また、本発明に係る第３のばり発生防止方法は、型締め時に、成形部形成用キャビティから伸びる隙間が生じる金型におけるばり発生防止方法であって、前記隙間を形成する金型端面における前記成形部形成用キャビティ寄りの部位に、ばりのばらつきを吸収するための凹部を形成するとともに、ゲートを介して前記成形部形成用キャビティに流し込まれた樹脂材料が前記隙間に到達して固化し、その後、前記成形部形成用キャビティが前記樹脂材料で完全充填されるよう、前記ゲートの位置を設定したことを特徴とする。
【００１０】
ここで、前記成形部形成用キャビティから伸びる隙間は、前記金型と、インサート部材との間の隙間であり、また、前記凹部は、前記インサート部材を保持するインサート部材保持部にばらつき吸収部を形成するためのキャビティに対応する。
本発明の第１の金型は、型締め時に、成形部形成用キャビティから伸びる隙間が生じる金型であって、ゲートを介して前記成形部形成用キャビティに流し込まれた樹脂材料が前記隙間に到達して固化し、その後、前記成形部形成用キャビティが前記樹脂材料で完全充填されるよう、前記ゲートの位置を設定したことを特徴とする。
ここで、前記隙間を形成する金型端面における前記成形部形成用キャビティ寄りの部位には、前記成形部形成用キャビティから前記隙間に向かって縮径するテーパ面からなる、ばりのばらつきを吸収するための凹部が形成される。
本発明の第２の金型は、型締め時に、成形部形成用キャビティから伸びる隙間が生じる金型であって、前記隙間を形成する金型端面における前記成形部形成用キャビティ寄りの部位に、前記成形部形成用キャビティから前記隙間に向かって縮径するテーパ面からなる、ばりのばらつきを吸収するための凹部を形成したことを特徴とする。
本発明の第１、第２の金型において、前記成形部形成用キャビティから伸びる隙間は、前記金型と、インサート部材との間の隙間であり、また、前記凹部は、前記インサート部材を保持するインサート部材保持部にばらつき吸収部を形成するためのキャビティに対応する。
本発明の第１の製造方法は、型締め時に、成形部形成用キャビティから伸びる隙間が生じる金型によって樹脂成形品を製造する製造方法であって、ゲートを介して前記成形部形成用キャビティに流し込まれた樹脂材料が前記隙間に到達して固化し、その後、前記成形部形成用キャビティが前記樹脂材料で完全充填されるよう、前記ゲートの位置を設定した金型を用い、前記ゲートから前記成形部形成用キャビティに流し込まれた樹脂材料が前記隙間に到達して固化し、その後、前記成形部形成用キャビティを前記樹脂材料で完全充填することを特徴とする。
ここで、前記金型には、前記隙間を形成する金型端面における前記成形部形成用キャビティ寄りの部位には、前記成形部形成用キャビティから前記隙間に向かって縮径するテーパ面からなる、ばりのばらつきを吸収するための凹部が形成されており、前記樹脂流し込み時、前記凹部は、前記凹部から前記隙間に到達する樹脂材料の流動抵抗を増大させ、前記隙間への樹脂材料の侵入を防ぐ。
本発明の第２の製造方法は、型締め時に、成形部形成用キャビティから伸びる隙間が生じる金型によって樹脂成形品を製造する製造方法であって、前記隙間を形成する金型端面における前記成形部形成用キャビティ寄りの部位に、前記成形部形成用キャビティから前記隙間に向かって縮径するテーパ面からなる、ばりのばらつきを吸収するための凹部を形成した金型を用い、樹脂流し込み時、前記凹部は、前記凹部から前記隙間に到達する樹脂材料の流動抵抗を増大させ、前記隙間への樹脂材料の侵入を防ぐことを特徴とする。
本発明の第１、第２の製造方法において、前記成形部形成用キャビティから伸びる隙間は、前記金型と、インサート部材との間の隙間であり、また、前記凹部は、前記インサート部材を保持するインサート部材保持部にばらつき吸収部を形成するためのキャビティに対応する。
本発明の第１、第２の製造方法において、前記樹脂成形品は、インジェクタスプールである。
本発明のインジェクタスプールは、ターミナルを構成するインサート金具（１）と、ボビン（２）及びインサート金具保持部（３）を有する樹脂成形部（４）とを備えるインジェクタスプール（Ｉ．Ｓ）であって、前記樹脂成形部（４）は、前記インサート金具（１）との間に隙間（１２）を生じる金型を用い、この金型により区画される成形部形成用キャビティ（１０）に樹脂材料を流し込んで成形されており、前記インサート金具保持部（３）は、前記成形部形成用キャビティから前記隙間（１２）に向かって縮径するテーパ面（１３）からなる凹部（１４）によって前記樹脂材料を成形してなるばらつき吸収部（５）を有することを特徴とする。
ここで、前記樹脂成形部（４）は、前記ボビン（２）と前記インサート金具保持部（３）との間に前記樹脂材料を流し込んだゲート（１１）を有する。
【００１１】
【発明の作用効果】
本発明に係る第１のばり発生防止方法によると、樹脂材料が成形部形成用キャビティに完全充填された時点では、既に、隙間に到達した樹脂材料は固化しているため、完全充填直後に成形部形成用キャビティの樹脂材料の圧力が保持圧力まで昇圧された時、固化した樹脂材料が隙間への樹脂材料の侵入を防ぐ壁の働きをする。このため、適用可能な成形品形状の範囲の拡大及び金型構造の簡単化を図りつつばりの発生を防止できる。
【００１２】
また、本発明に係る第２のばり発生防止方法によると、成形部形成用キャビテイと隙間との間に形成された凹部が、隙間に到達する樹脂材料の流動抵抗を増大させ、樹脂材料の隙間への侵入を防ぐ働きをする。このため、適用可能な成形品形状の範囲の拡大及び金型構造の簡単化を図りつつばりの発生を防止できる。
【００１３】
また、本発明に係る第３のばり発生防止方法によると、樹脂材料が成形部形成用キャビティに完全充填された時点では、既に、隙間に到達した樹脂材料は固化しているため、完全充填直後に成形部形成用キャビティの樹脂材料の圧力が保持圧力まで昇圧された時、固化した樹脂材料が隙間への樹脂材料の侵入を防ぐ壁の働きをし、また、成形部形成用キャビテイと隙間との間に形成された凹部が、樹脂材料の流動抵抗を増大させ、隙間への樹脂材料の侵入を防ぐ働きをする。このため、適用可能な成形品形状の範囲の拡大及び金型構造の簡単化を図りつつばりの発生を防止でき、上記第１、第２のばり発生防止方法と比べ効果が大である。
【００１５】
【実施例】
以下、本発明の一実施例に係るばり発生防止方法を、図２に示すようなインジェクタスプールＩ．Ｓを製造する場合を例にとって説明する。ここで、図２図示のインジェクタスプールＩ．Ｓは、ターミナルを構成するインサート金具１，１と、ボビン２及びインサート金具保持部３から構成される樹脂成形部４と、からなり、インサート金具保持部３には、樹脂流し込み時に発生するばりのばらつきを吸収するためのばらつき吸収部５，５が形成されている。
【００１６】
上記のようなインジェクタスプールＩ．Ｓを製造する金型を図３及び図４に概略的に示す。ここで、図３及び図４は、型締め時の構成を示し、また、断面の切口は、金型の構造を分かり易くするために適宜選択されている。
【００１７】
図３及び図４において、符号６は上型、７は下型、８はスライドコア、９はアンギュラーピン、１０は上記樹脂成形部４の形状に対応した形状を有する成形部形成用キャビティ、１１はゲートをそれぞれ表わしている。
【００１８】
図６（Ａ）は、図４図示ａ部分を拡大して示している。この図６（Ａ）に示すように、スライドコア８の一面には、成形部形成用キャビティ１０から隙間１２に向かって縮径するテーパ面１３からなる凹部１４が形成されている。この凹部１４は、上記ばらつき吸収部５が形成されるキャビティに対応している。
【００１９】
ゲート１１の位置は、図５に示す成形品製造サイクルにおける樹脂流し込み時に、ゲート１１を介して成形部形成用キャビティ１０に流し込まれた樹脂材料１５が凹部１４に到達して固化し、その後、成形部形成用キャビティ１０が樹脂材料１５で完全充填されるよう、図２に示すように、隙間１２近くに設定されている。
【００２０】
すなわち、樹脂流し込み時の凹部１４の樹脂圧力の変化を示す図１において、充填工程において樹脂材料１５が凹部１４に到達した時点Ｔ_１から完全充填される時点Ｔ_３までにかかる時間ｔ_１が、樹脂材料１５が凹部１４に到達した時点Ｔ_１から凹部１４の樹脂材料１５が固化する時点Ｔ_２までにかかる時間ｔ_０よりも長くなるようにゲート１１の位置を設定した。
【００２１】
次に、このようなゲート１１の位置の設定を具体的に行なう方法を下記▲１▼及び▲２▼に示す。
【００２２】
▲１▼トライ・アンド・エラーの実験からゲート１１の位置を設定する。
【００２３】
▲２▼下記１）、２）に示す単純な計算からゲート１１の位置を設定する。
【００２４】
１）スプルーに樹脂流し込みを開始した時点（図１図示時点Ｔ_０）から完全充填時点Ｔ_３までにかかる時間（図１図示時間ｔ_２）を経験又は測定により求める。次に、スプルー及びランナーの体積（多数個取りの場合は、１個当たりに換算した体積）と、仮に定めたゲート１１の位置からばり発生位置（隙間１２）までの体積との和Ａ_１、すなわち、ばり発生位置（隙間１２）まで樹脂材料１５を流し込むのに要する射出量Ａ_１を数学的に求める。また、全体の体積（Ａ_１と樹脂成形部４の残りの体積との和）Ａ_２を数学的に求める。そして、体積Ａ_１と体積Ａ_２との比Ａ_１／Ａ_２を数学的に求め、（１−Ａ_１／Ａ_２）×ｔ_２＞ｔ_０となるようなゲート１１の位置を求める。ここで、固化時間ｔ_０は、樹脂名及び凹部１４の幅（ばらつき吸収部５の肉厚）に応じて実験等で求めた下記表１に示す数値を用いる。
【００２５】
【表１】

【００２６】
２）ゲート１１から樹脂材料１５が流れ込む時点Ｔ_４から完全充填時点Ｔ_３までの時間ｔ_３が明らかな場合は、仮に定めたゲート１１の位置からばり発生位置（隙間１２）までの体積Ａ_３（ゲート１１の位置からばり発生位置（隙間１２）までの距離Ｌ_３でもよい。）と、樹脂成形部４の体積Ａ_４（ゲート１１の位置から樹脂成形部４の中で一番遠い距離Ｌ_４でもよい。）との比Ａ_３／Ａ_４（Ｌ_３／Ｌ_４）を数学的に求め、（１−Ａ_３／Ａ_４）×ｔ_３＞ｔ_０となるようなゲート１１の位置を求める。
【００２７】
一方、凹部１４（ばらつき吸収部５）の形状寸法は、隙間１２に樹脂材料１５が流れ込まず、かつ、樹脂成形部４から離脱しないよう、トライ・アンド・エラーの実験により設定されている。また、精度は劣るが、理論式又は経験式を用いて凹部１４（ばらつき吸収部５）の形状寸法を設定することもできる。例えば、幅（肉厚）ｈが一定の凹部１４（ばらつき吸収部５）の深さ（長さ）Ｌは、下記式から求めるようにする。
【００２８】
Ｌ≧√（ｈ^２・ｔ_０・Ｐ_Ｂ／１２η）
（ただし、Ｐ_Ｂ；凹部１４（ばらつき吸収部５）の樹脂材料１５が固化した時の凹部１４（ばらつき吸収部５）の樹脂材料１５の圧力（図１参照），η；成形中の樹脂材料１５の見掛け粘度）
ここで、Ｐ_Ｂ及びηは、成形中の樹脂材料１５の圧力を測定することにより求めることができるが、樹脂材料や樹脂成形部４の肉厚及び成形条件によって決まる値なので、予め求めた実験値、経験値を用いてもよい。なお、凹部１４（ばらつき吸収部５）の形状が幅（肉厚）一定でない場合でも、上記と同様に、その形状寸法を設定することができる。
【００２９】
上記のようにゲート１１の位置を隙間１２の近くに設定し、かつ、凹部１４（ばらつき吸収部５）を形成した場合の効果を下記表２に示す。
【００３０】
【表２】

【００３１】
上記表２から明らかなように、ゲート１１の位置を隙間１２から遠くに設定し、かつ、凹部１４（ばらつき吸収部５）を形成しない場合、及び、ゲート１１の位置を隙間１２の近くに設定し、かつ、凹部１４（ばらつき吸収部５）を形成しない場合と比べ、ばりの高さは大幅に減少し零になった。
【００３２】
このような結果は、以下に述べる理由によるものと推察される。
【００３３】
ゲート１１の位置を上述したように隙間１２近くに設定したことにより、樹脂材料１５が成形部形成用キャビティ１０に完全充填された時点では、既に、隙間１２に到達した樹脂材料１５は固化しているため、完全充填直後に成形部形成用キャビティ１０の樹脂材料１５の圧力が保持圧力まで昇圧された時、固化した樹脂材料１５が隙間１２への樹脂材料１５の侵入を防ぐ壁としての働きをする。このため、隙間１２に樹脂材料１５が侵入してばりが発生する度合を低下させることできるようになるのである。
【００３４】
また、樹脂流し込み時、成形部形成用キャビテイ１０と隙間１２との間に形成された凹部１４は、隙間１２に到達する樹脂材料１５の流動抵抗を増大させ、隙間１２への樹脂材料１５の侵入を防ぐ働きをする（図６（Ｂ）参照）。このため、凹部１４によっても、隙間１２に樹脂材料１５が侵入してばりが発生する度合を低下させることができるのである。
【００３５】
なお、上記実施例では、ゲート１１の位置設定及び凹部１４の形状設定を実験又は実験と簡単な計算の組合により行なっているが、市販の樹脂流動、保圧解析ソフトを用いて、充填挙動及び樹脂粘度、樹脂圧力挙動等を予測することによって設定するようにしてもよい。また、解析ソフト中に、上述したゲート位置設定及び凹部寸法設定の考え方を組み込むようにしてもよい。
【００３６】
また、上記実施例では、ゲート位置設定と凹部形状設定の組み合わせによりばり発生防止を図っているが、本発明は、これに限定されるものではなく、上記表２から導き出されるように、ゲート位置設定のみ、又は凹部形状設定のみによりばり発生防止を図るようにしても十分な効果を得ることができる。
【００３７】
図７は、他の実施例に係るばり発生防止方法を示している。
【００３８】
このばり発生防止方法は、成形条件によりばりの発生を防止する方法に関するものであり、ゲート１１の位置が、上述した条件（ｔ_０＜ｔ_１）を満たしていない場合であっても、凹部１４に樹脂材料１５が流れ込んでから急激に圧力上昇が生じるまでの時間ｔ_１がｔ_０よりも長くなるように、射出速度、射出圧又は保持圧力を低く設定したものである。
【００３９】
このため、本実施例によっても、凹部１４の樹脂材料１５が固化した後に樹脂圧力が急激に上昇することから、隙間１２への樹脂材料１５の侵入を防止し、ばりの発生を防止することができる。
【００４０】
なお、上記各実施例では、板状のインサート金具１を有する樹脂成形品Ｉ．Ｓについて述べているが、本発明は、これに限定されるものではなく、ブロック、丸線等の形状を有するインサート金具についても、また、樹脂、ゴム、セラミック等の材質のインサート部材についても適用しうるものである。
【００４１】
また、上記各実施例では、インサート金具１と金型７，８との間の隙間１２に生じるばりの発生を防止しているが、本発明はこれに限定されるものではなく、他に、エアベント部、型合わせ部、型分割部に発生するばりに対しても適用することができる。
【図面の簡単な説明】
【図１】一実施例に係るばり発生防止方法を説明するための、樹脂流し込み時の凹部の樹脂圧力の変化曲線図
【図２】上記ばり発生防止方法を適用して製造される樹脂成形品（インジェクタスプール）の斜視図
【図３】上記ばり発生防止方法を実施する金型の断面図
【図４】上記金型の他の切口による断面図
【図５】上記樹脂成形品の製造サイクルを示すフローチャート
【図６】図４図示ａ部分の拡大断面図
【図７】他の実施例を説明するための、樹脂流し込み時の隙間の樹脂圧力の変化曲線図
【図８】従来の問題点を説明するための金型の要部拡大断面図
【符号の説明】
Ｉ．Ｓインジェクタスプール
１インサート金具（インサート部材）
２ボビン
３インサート金具保持部（インサート部材保持部）
４樹脂成形部
５ばらつき吸収部
７，８金型
１０成形部形成用キャビティ
１１ゲート
１２隙間
１３テーパ面
１４凹部
１５樹脂材料[0001]
[Industrial application fields]
The present invention relates to a flash generation preventing method, and more particularly, to a flash generation preventing method for preventing flash generated in a gap in a mold in which a gap extending from a molded part forming cavity is formed at the time of mold clamping.
[0002]
[Prior art]
For example, in a mold in which a metal part is inserted and a resin molded product is injection-molded, as shown in FIG. 8, a gap 12 is generated between the peripheral surface of the insert metal part 1 and one surface of the mold 8 during mold clamping. When the resin is poured, there is a problem that the resin material 15 enters the gap 12 and the flash 16 is integrally attached to the resin molded product taken out after the mold is opened.
[0003]
Although this gap 12 can be reduced depending on the dimensional accuracy of the insert fitting 1 or the molding method, there is a limit to the improvement of the dimensional accuracy of the insert fitting 1, so this gap 12 is eliminated from the occurrence of flash 16. It was extremely difficult to reduce the size to the minimum. Moreover, although it is possible to prevent generation | occurrence | production of the burr | flash 16 with a shaping | molding method, conventionally, it relied on the operator's experience and intuition, and it was difficult to always prevent generation | occurrence | production of the burr | flash 16.
[0004]
Japanese Patent Laid-Open No. 4-182105 discloses a mold structure that facilitates deburring by forming a thick burr.
[0005]
[Problems to be solved by the invention]
However, since the above-described prior art requires a runner or the like to be disposed at the flash generation position, there are limitations on the shape of an applicable molded product, and the mold structure is complicated.
[0006]
An object of the present invention is to solve the above-mentioned problems, and to provide a method for preventing the occurrence of flash while expanding the range of applicable molded product shapes and simplifying the mold structure.
[0007]
[Means for Solving the Problems]
A first burr generation preventing method according to the present invention is a burr generation preventing method in a mold in which a gap extending from a molded part forming cavity is generated at the time of mold clamping, and is poured into the molded part forming cavity via a gate. The position of the gate is set so that the resin material thus obtained reaches the gap and is solidified, and then the molding part forming cavity is completely filled with the resin material.
[0008]
The second burr generation preventing method according to the present invention is a burr generation preventing method in a mold in which a gap extending from the molding part forming cavity is generated at the time of mold clamping, and the burr generation preventing method in the mold end surface forming the gap is provided. A concave portion for absorbing a variation in flash, which is formed of a tapered surface having a diameter reduced from the molding portion forming cavity toward the gap, is formed in a portion near the molding portion forming cavity .
[0009]
The third burr generation preventing method according to the present invention is a burr generation preventing method in a mold in which a gap extending from the molding part forming cavity is generated at the time of clamping, wherein the burr generation preventing method is performed on the mold end surface forming the gap. While forming a recess for absorbing the variation of the flash in a part near the molding part forming cavity, the resin material poured into the molding part forming cavity through the gate reaches the gap and solidifies, Then, the position of the gate is set so that the molding part forming cavity is completely filled with the resin material.
[0010]
Here, the gap extending from the molding part forming cavity is a gap between the mold and the insert member, and the recess has a variation absorbing part in the insert member holding part that holds the insert member. Corresponds to the cavity to be formed.
The first mold of the present invention is a mold in which a gap extending from the molded part forming cavity is generated when the mold is clamped, and the resin material poured into the molded part forming cavity through a gate is placed in the gap. The position of the gate is set so that it reaches and solidifies, and then the molding part forming cavity is completely filled with the resin material.
Here, a portion of the mold end face forming the gap near the molding part forming cavity absorbs the variation of the flash, which is a tapered surface having a diameter reduced from the molding part forming cavity toward the gap. A recess is formed.
The second mold of the present invention is a mold in which a gap extending from the molding part forming cavity is generated at the time of clamping, and in a portion near the molding part forming cavity on the mold end surface forming the gap, A concave portion for absorbing a variation in the flash, which is formed of a tapered surface whose diameter is reduced from the molding portion forming cavity toward the gap, is formed.
In the first and second molds of the present invention, the gap extending from the molding part forming cavity is a gap between the mold and the insert member, and the recess holds the insert member. This corresponds to a cavity for forming a variation absorbing portion in the insert member holding portion.
A first manufacturing method of the present invention is a manufacturing method for manufacturing a resin molded product by a mold in which a gap extending from a molded part forming cavity is generated at the time of clamping, and the molded part forming cavity is connected to the molded part forming cavity through a gate. The poured resin material reaches the gap and solidifies, and then, using a mold in which the position of the gate is set so that the molding part forming cavity is completely filled with the resin material, The resin material poured into the molding part forming cavity reaches the gap and solidifies, and then the molding part forming cavity is completely filled with the resin material.
Here, the mold includes a tapered surface that is reduced in diameter from the molding part forming cavity toward the gap at a part near the molding part forming cavity on the mold end surface that forms the gap. A recess is formed to absorb the dispersion of the flash, and when the resin is poured, the recess increases the flow resistance of the resin material that reaches the gap from the recess and prevents the resin material from entering the gap. prevent.
The second manufacturing method of the present invention is a manufacturing method for manufacturing a resin molded product by a mold in which a gap extending from a molding portion forming cavity is generated at the time of mold clamping, and the molding on the mold end surface that forms the gap When a resin is poured into a part near the part forming cavity, a mold having a concave part for absorbing the variation of the flash, which is formed of a tapered surface whose diameter is reduced from the molding part forming cavity toward the gap, The concave portion increases the flow resistance of the resin material reaching the gap from the concave portion and prevents the resin material from entering the gap.
In the first and second manufacturing methods of the present invention, the gap extending from the molding part forming cavity is a gap between the mold and the insert member, and the recess holds the insert member. This corresponds to a cavity for forming a variation absorbing portion in the insert member holding portion.
In the first and second manufacturing methods of the present invention, the resin molded product is an injector spool.
The injector spool of the present invention is an injector spool (IS) including an insert fitting (1) constituting a terminal, and a resin molded portion (4) having a bobbin (2) and an insert fitting holding portion (3). The resin molding part (4) uses a mold that forms a gap (12) between the insert metal fitting (1) and a resin material in the molding part forming cavity (10) partitioned by the mold. The insert fitting holding portion (3) is formed by the concave portion (14) having a tapered surface (13) whose diameter is reduced from the molding portion forming cavity toward the gap (12). It has a variation absorption part (5 ) formed by molding a material .
Here, the said resin molding part (4) has the gate (11) which poured the said resin material between the said bobbin (2) and the said insert metal fitting holding part (3).
[0011]
[Effects of the invention]
According to the first flash generation preventing method according to the present invention, when the resin material is completely filled in the molding part forming cavity, the resin material that has already reached the gap is already solidified, so that molding is performed immediately after complete filling. When the pressure of the resin material in the part forming cavity is increased to the holding pressure, the solidified resin material functions as a wall that prevents the resin material from entering the gap. For this reason, generation | occurrence | production of a flash can be prevented, aiming at the expansion of the range of the applicable molded article shape, and simplification of a metal mold | die structure.
[0012]
In addition, according to the second method for preventing the occurrence of flash according to the present invention, the recess formed between the cavity for forming part formation and the gap increases the flow resistance of the resin material reaching the gap, and the gap of the resin material It works to prevent intrusion. For this reason, generation | occurrence | production of a flash can be prevented, aiming at the expansion of the range of the applicable molded article shape, and simplification of a metal mold | die structure.
[0013]
In addition, according to the third method for preventing occurrence of flash according to the present invention, the resin material that has already reached the gap is already solidified at the time when the resin material is completely filled into the molding part forming cavity. When the pressure of the resin material in the molding part forming cavity is increased to the holding pressure, the solidified resin material acts as a wall that prevents the resin material from entering the gap, and the molding part forming cavity and the gap The concave portion formed between the two functions to increase the flow resistance of the resin material and prevent the resin material from entering the gap. For this reason, it is possible to prevent the occurrence of burrs while expanding the range of applicable molded product shapes and simplifying the mold structure, which is more effective than the first and second burrs prevention methods.
[0015]
【Example】
Hereinafter, a flash occurrence prevention method according to an embodiment of the present invention will be described with reference to an injector spool I.D. A case where S is manufactured will be described as an example. Here, the injector spool I.D shown in FIG. S is composed of the

insert metal fittings

1 and 1 constituting the terminal and the resin molding part 4 constituted by the bobbin 2 and the insert metal holding part 3. The insert metal holding part 3 has a flash generated when the resin is poured.

Variation absorbing portions

5 and 5 for absorbing variation are formed.
[0016]
The injector spool I.I. A mold for producing S is schematically shown in FIGS. Here, FIG. 3 and FIG. 4 show the configuration at the time of mold clamping, and the cut surface of the cross section is appropriately selected in order to make the structure of the mold easy to understand.
[0017]
3 and 4, reference numeral 6 is an upper mold, 7 is a lower mold, 8 is a slide core, 9 is an angular pin, 10 is a molded part forming cavity having a shape corresponding to the shape of the resin molded part 4, Reference numeral 11 denotes a gate.
[0018]
FIG. 6A shows an enlarged view of the portion a shown in FIG. As shown in FIG. 6A, a concave portion 14 is formed on one surface of the slide core 8. The concave portion 14 includes a tapered surface 13 whose diameter decreases from the molding portion forming cavity 10 toward the gap 12. The concave portion 14 corresponds to a cavity in which the variation absorbing portion 5 is formed.
[0019]
The position of the gate 11 is such that when the resin is poured in the molded product manufacturing cycle shown in FIG. 5, the resin material 15 poured into the molding portion forming cavity 10 through the gate 11 reaches the recess 14 and solidifies, and then molded. As shown in FIG. 2, it is set near the gap 12 so that the part forming cavity 10 is completely filled with the resin material 15.
[0020]
That is, in FIG. 1 showing the change in the resin pressure in the recess 14 when the resin is poured, the time t ₁ required from the time T ₁ when the resin material 15 reaches the recess 14 in the filling process to the time T ₃ when the resin material 15 is completely filled is The position of the gate 11 was set to be longer than the time t ₀ required from the time T ₁ when the resin material 15 reached the recess 14 to the time T ₂ when the resin material 15 in the recess 14 solidified.
[0021]
Next, a method for concretely setting the position of the gate 11 is shown in the following (1) and (2).
[0022]
(1) The position of the gate 11 is set from a trial-and-error experiment.
[0023]
(2) The position of the gate 11 is set from the simple calculation shown in 1) and 2) below.
[0024]
1) The time (time t ₂ shown in FIG. 1) required from the time when resin pouring starts to the sprue (time T ₀ shown in FIG. 1) to the complete filling time T ₃ is obtained by experience or measurement. Next, the sum A ₁ of the volume of the sprue and runner (in the case of multi-cavity, the volume converted per piece) and the volume from the position of the gate 11 to the position where the flash is generated (gap 12), that is, mathematically determine the injection amount a ₁ required to pour the resin material 15 to burr generation position (the gap 12). Further, the total volume (A ₁ and the sum of the remaining volume of the resin molded portion 4) A ₂ mathematically determined. Then, mathematically determine the ratio _A 1 / _{A 2} between the volume _{A 1} and volume _{A 2,} determining the position of the _{_{(1-A 1 / A 2}} ) × t 2> t 0 and becomes like a gate 11. Here, as the solidification time t ₀ , the numerical values shown in Table 1 below obtained by experiments or the like according to the resin name and the width of the concave portion 14 (the thickness of the variation absorbing portion 5) are used.
[0025]
[Table 1]

[0026]
2) If the time from the gate 11 from the time _{T 4} the resin material 15 flows to completely fill time _{T 3} _{t 3} is apparent, burr generation position from the provisionally determined position of the gate 11 (volume _{A 3} until the gap 12) (It may be the distance L ₃ from the position of the gate 11 to the burr generation position (gap 12)) and the volume A ₄ of the resin molded part ₄ (the distance L farthest from the position of the gate 11 in the resin molded part 4). ₄ ), the ratio of A ₃ / A ₄ (L ₃ / L ₄ ) is obtained mathematically, and the position of the gate 11 such that (1−A ₃ / A ₄ ) × t ₃ > t ₀ is obtained. Ask.
[0027]
On the other hand, the shape dimension of the recess 14 (variation absorbing portion 5) is set by a trial and error experiment so that the resin material 15 does not flow into the gap 12 and does not leave the resin molded portion 4. In addition, although the accuracy is inferior, the shape dimension of the recess 14 (variation absorbing portion 5) can be set using a theoretical formula or an empirical formula. For example, the depth (length) L of the concave portion 14 (variation absorbing portion 5) having a constant width (thickness) h is obtained from the following equation.
[0028]
L ≧ √ (h ² · t ₀ · P _B / 12η)
(However, P _B ; pressure of the resin material 15 in the concave portion 14 (variation absorbing portion 5) when the resin material 15 in the concave portion 14 (variation absorbing portion 5) is solidified (see FIG. 1), η; resin material being molded 15 apparent viscosity)
Here, P _B and η can be obtained by measuring the pressure of the resin material 15 during molding. However, since P _B and η are values determined by the thickness of the resin material and the resin molded portion 4 and the molding conditions, the experiment obtained in advance is performed. Values and experience values may be used. Even when the shape of the concave portion 14 (variation absorbing portion 5) is not constant in width (thickness), the shape dimension can be set similarly to the above.
[0029]
The effect when the position of the gate 11 is set near the gap 12 as described above and the concave portion 14 (variation absorbing portion 5) is formed is shown in Table 2 below.
[0030]
[Table 2]

[0031]
As apparent from Table 2 above, the position of the gate 11 is set far from the gap 12 and the recess 14 (variation absorbing portion 5) is not formed, and the position of the gate 11 is set near the gap 12. And compared with the case where the recessed part 14 (variation absorption part 5) is not formed, the height of the burr | flash reduced significantly and became zero.
[0032]
Such a result is assumed to be due to the following reason.
[0033]
Since the position of the gate 11 is set near the gap 12 as described above, the resin material 15 that has already reached the gap 12 is solidified when the resin material 15 is completely filled in the molding portion forming cavity 10. Therefore, when the pressure of the resin material 15 in the molding portion forming cavity 10 is increased to the holding pressure immediately after complete filling, the solidified resin material 15 functions as a wall that prevents the resin material 15 from entering the gap 12. To do. For this reason, the degree to which the resin material 15 enters the gap 12 and a flash is generated can be reduced.
[0034]
Further, when the resin is poured, the recess 14 formed between the molded part forming cavity 10 and the gap 12 increases the flow resistance of the resin material 15 reaching the gap 12, and the resin material 15 enters the gap 12. (See FIG. 6B). For this reason, the degree to which the resin material 15 enters the gap 12 and the flash is generated can also be reduced by the concave portion 14.
[0035]
In addition, in the said Example, although the position setting of the gate 11 and the shape setting of the recessed part 14 are performed by the combination of experiment or experiment and simple calculation, using a commercially available resin flow and pressure retention analysis software, filling behavior and You may make it set by estimating resin viscosity, resin pressure behavior, etc. Moreover, you may make it incorporate the idea of the gate position setting mentioned above and a recessed part dimension setting in analysis software.
[0036]
Further, in the above embodiment, the occurrence of flash is prevented by a combination of the gate position setting and the concave shape setting, but the present invention is not limited to this, and as derived from Table 2 above, the gate position is set. A sufficient effect can be obtained even if only the setting or the concave shape setting is used to prevent the occurrence of flash.
[0037]
FIG. 7 shows a flash generation preventing method according to another embodiment.
[0038]
This burr generation prevention method relates to a method for preventing burr generation depending on molding conditions, and even when the position of the gate 11 does not satisfy the above-described condition (t ₀ <t ₁ ), the concave portion 14. The injection speed, injection pressure, or holding pressure is set low so that the time t ₁ from when the resin material 15 flows to the time when the pressure rises suddenly becomes longer than t ₀ .
[0039]
For this reason, also in this embodiment, since the resin pressure rapidly increases after the resin material 15 in the recess 14 is solidified, it is possible to prevent the resin material 15 from entering the gap 12 and to prevent the occurrence of flash. it can.
[0040]
In each of the above-described embodiments, the resin molded product I.I. Although S is described, the present invention is not limited to this, and is also applicable to insert fittings having shapes such as blocks and round wires, and also to insert members made of resin, rubber, ceramics, and the like. It is possible.
[0041]
Moreover, in each said Example, although generation | occurrence | production of the flash which arises in the clearance gap 12 between the insert metal fitting 1 and the metal mold | dies 7 and 8 is prevented, this invention is not limited to this, In addition, The present invention can also be applied to flash generated in an air vent part, a mold matching part, and a mold division part.
[Brief description of the drawings]
FIG. 1 is a curve diagram showing a change in resin pressure in a recess during resin pouring for explaining a method for preventing flash generation according to an embodiment. FIG. 2 is a resin molded product manufactured by applying the method for preventing flash generation. FIG. 3 is a cross-sectional view of a mold for carrying out the above-described method for preventing the occurrence of burrs. FIG. 4 is a cross-sectional view of another mold of the mold. FIG. FIG. 6 is an enlarged cross-sectional view of the portion a shown in FIG. 4. FIG. 7 is a curve diagram of a change in the resin pressure in the gap when the resin is poured to explain another embodiment. Expansive sectional view of the main part of the mold for explanation
I. S injector spool
1 Insert bracket (insert member)
2 bobbins
3 Insert bracket holder (insert member holder)
4 resin molding part
5

Variation absorbing part

7, 8 Mold 10 Molded part forming cavity 11 Gate 12 Clearance
13

Tapered surface

14 Recess 15 Resin material

Claims

A method for preventing burrs from occurring in a mold in which a gap extending from a cavity for forming a molded part is generated during mold clamping,
The position of the gate is set so that the resin material poured into the molding part forming cavity through the gate reaches the gap and solidifies, and then the molding part forming cavity is completely filled with the resin material. A flash generation prevention method characterized by being set.

A method for preventing burrs from occurring in a mold in which a gap extending from a cavity for forming a molded part is generated during mold clamping,
A concave portion for absorbing variation in the flash, which is formed of a tapered surface that decreases in diameter from the molding portion forming cavity toward the gap, in a portion near the molding portion forming cavity on the mold end surface that forms the gap. A method for preventing the occurrence of burrs, characterized in that it is formed.

A method for preventing burrs from occurring in a mold in which a gap extending from a cavity for forming a molded part is generated during mold clamping,
While forming a recess for absorbing the variation of the flash in the portion near the molding part forming cavity in the mold end surface forming the gap,
The position of the gate is set so that the resin material poured into the molding part forming cavity through the gate reaches the gap and solidifies, and then the molding part forming cavity is completely filled with the resin material. A flash prevention method characterized by setting.

In the flash generation | occurrence | production prevention method in any one of Claim 1 to 3,
The method for preventing flash generation, wherein the gap extending from the molding part forming cavity is a gap between the mold and the insert member.

In the flash generation | occurrence | production prevention method of Claim 2 or 3,
The gap extending from the molding part forming cavity is a gap between the mold and the insert member,
The said recessed part respond | corresponds to the cavity for forming the dispersion | variation absorption part in the insert member holding part holding the said insert member, The flash generation | occurrence | production prevention method characterized by the above-mentioned.

A mold that creates a gap extending from the cavity for forming the molded part when clamping,
The position of the gate is set so that the resin material poured into the molding part forming cavity through the gate reaches the gap and solidifies, and then the molding part forming cavity is completely filled with the resin material. Mold characterized by setting.

The mold according to claim 6, wherein
A concave portion for absorbing variation in the flash, which is formed of a tapered surface whose diameter is reduced from the molding part forming cavity toward the gap, in a portion near the molding part forming cavity on the mold end face forming the gap. A mold characterized by being formed.

A mold that creates a gap extending from the cavity for forming the molded part when clamping,
A concave portion for absorbing variation in the flash, which is formed of a tapered surface whose diameter is reduced from the molding part forming cavity toward the gap, in a portion near the molding part forming cavity on the mold end face forming the gap. A mold characterized by being formed.

The mold according to any one of claims 6 to 8,
The mold characterized in that the gap extending from the molding part forming cavity is a gap between the mold and the insert member.

The mold according to claim 7 or 8,
The gap extending from the molding part forming cavity is a gap between the mold and the insert member,
The concave portion has a variation absorbing portion in an insert member holding portion that holds the insert member. A mold characterized by corresponding to a cavity for forming.

A manufacturing method for manufacturing a resin molded product by a mold in which a gap extending from a molded part forming cavity is formed during mold clamping,
The position of the gate is set so that the resin material poured into the molding part forming cavity through the gate reaches the gap and solidifies, and then the molding part forming cavity is completely filled with the resin material. Using the set mold,
A resin molded product characterized in that a resin material poured from the gate into the molding part forming cavity reaches the gap and solidifies, and then the molding part forming cavity is completely filled with the resin material. Manufacturing method to manufacture.

In the manufacturing method which manufactures the resin molded product of Claim 11,
The mold has a variation in flash, which is formed of a tapered surface that is reduced in diameter from the molding portion forming cavity toward the gap at a portion near the molding portion forming cavity on the mold end surface that forms the gap. A recess for absorbing is formed,
The manufacturing method of manufacturing a resin molded product, wherein the concave portion increases the flow resistance of the resin material reaching the gap from the concave portion and prevents the resin material from entering the gap when the resin is poured.

A manufacturing method for manufacturing a resin molded product by a mold in which a gap extending from a molded part forming cavity is formed during mold clamping,
A concave portion for absorbing variation in the flash, which is formed of a tapered surface whose diameter is reduced from the molding part forming cavity toward the gap, in a portion near the molding part forming cavity on the mold end face forming the gap. Using the formed mold,
The method of manufacturing a resin molded product, wherein the recess increases the flow resistance of the resin material reaching the gap from the recess and prevents the resin material from entering the gap when the resin is poured.

In the manufacturing method which manufactures the resin molded product in any one of Claim 11 to 13,
A manufacturing method for manufacturing a resin molded product, wherein a gap extending from the molding part forming cavity is a gap between the mold and an insert member.

In the manufacturing method which manufactures the resin molded product of Claim 12 or 13,
The gap extending from the molding part forming cavity is a gap between the mold and the insert member,
The said recessed part respond | corresponds to the cavity for forming a dispersion | variation absorption part in the insert member holding part holding the said insert member, The manufacturing method which manufactures the resin molded product characterized by the above-mentioned.

In the manufacturing method which manufactures the resin molded product in any one of Claim 11 to 15,
The manufacturing method for manufacturing a resin molded product, wherein the resin molded product is an injector spool.

An injector spool (IS) comprising an insert fitting (1) constituting a terminal and a resin molded part (4) having a bobbin (2) and an insert fitting holding part (3),
The resin molded part (4)
Using a mold that creates a gap (12) between the insert metal fitting (1), a resin material is poured into a molding part forming cavity (10) defined by the mold, and the mold is formed.
The insert fitting holding part (3)
It has a variation absorbing part (5) formed by molding the resin material by a concave part (14) comprising a tapered surface (13) whose diameter decreases from the molding part forming cavity toward the gap (12). Injector spool.

The injector spool according to claim 17,
The resin molding part (4) is located between the bobbin (2) and the insert fitting holding part (3). An injector spool having a gate (11) into which the resin material is poured.