JP4034996B2 - Molding method - Google Patents

Description

そして、型閉力は１５０ｔ、型内樹脂圧力は４００ｋｇ／ｃｍ²、入れ子４〜１２の縦弾性係数は２．１×１０^-6ｋｇ／ｃｍ²とした。位置は、型開時の入れ子４の先端（キャビティ周縁部１５の先端）を基準とする。
【００２９】
［計算例１］
まず、従来のようにキャビティ周縁部１５とピン１４の高さを調整した場合について計算する。
【００３０】
本例では、窓部の内側のバリを防ぐために、窓部を形成するためのピン１４をキャビティ周縁部１５より高くし、ピン１４の接触圧を高くする場合について検討した。具体的には、入れ子４のキャビティ周縁部１５の高さを基準（０）として、入れ子６，８〜１２のキャビティ周縁部１５の高さをそれと一致させ、入れ子５，７のピン１４の高さを＋１０μｍとした。この場合、表２に示すように、樹脂充填時には各入れ子とも２．５１μｍだけ後退するように圧縮される。
【００３１】
【表２】

樹脂充填時における、入れ子４，８のキャビティ周縁部１５の先端の接触圧は１１５７ｋｇ／ｃｍ²であり、入れ子５，７のピン１４の先端の接触圧は１７５１ｋｇ／ｃｍ²であり、これらの入れ子においてバリは発生しない。しかし、入れ子６のキャビティ周縁部１５の先端の接触圧は７７０ｋｇ／ｃｍ²、入れ子９〜１２のキャビティ周縁部１５の先端の接触圧は７８６ｋｇ／ｃｍ²しかないため、これらの入れ子６，９〜１２の部分では接触圧が不足し、バリが発生しやすい。
【００３２】
［計算例２］
そこで、キャビティ周縁部１５とピン１４の高さをより細かく微調整してバリの発生を抑える方法について検討した。
【００３３】
すなわち、入れ子４のキャビティ周縁部１５の高さを基準（０）として、入れ子８のキャビティ周縁部１５の高さをそれと一致させ、入れ子５，７のピン１４の高さを＋７．８０μｍとし、入れ子６のキャビティ周縁部１５の高さを＋０．９１μｍとし、入れ子９〜１２のキャビティ周縁部１５の高さを＋０．８３μｍにした。この場合、表３に示すように、樹脂充填時には、各入れ子とも２．６３μｍだけ後退するように圧縮され、各入れ子の先端の接触圧は１１７７ｋｇ／ｃｍ²で均一になる。
【００３４】
【表３】

従って、この場合、高さの微調整によってバリの発生が抑えられることが判ると同時に、計算例１の結果と比較すると、僅か数μｍの高さの違いで、接触圧が大幅に変動することが判る。すなわち、ピン１４やキャビティ周縁部１５の僅かな（例えば０．１μｍのオーダーの）高低によって、窓部や成形品周囲のバリの出方が大幅に異なることが理解される。
【００３５】
以上のように、計算上ではバリの発生を抑えられることが判ったが、０．１μｍ以下のオーダーでキャビティ周縁部１５とピン１４の高さを正確に調整することは、機械加工上、非常に大変な作業である。そして、計算例１および２を比較すると、ごく僅かな誤差が存在するだけで、接触圧が大幅に変動してバリの発生をもたらすことが明白である。従って、実際的には非常に難しい方法であるといえる。
【００３６】
また、前記した通り、このような機械加工による各入れ子の高さの微調整は、非可逆的なものであり、再調整が困難であるため、環境変化や経時的な条件変化に伴うバリの発生状況の変化には対応できないという不都合がある。
【００３７】
［計算例３］
次に、本発明を採用して各入れ子の温度を独立して微調整する場合について検討した。各入れ子４〜１２のキャビティ周縁部１５およびピン１４の高さを全て等しくし、入れ子５，７の樹脂充填時の温度を、入れ子４，６，８〜１２の樹脂充填時の温度よりも１５℃高くなるようにした。これによると、樹脂充填時には各入れ子とも１０．１７μｍだけ後退するように圧縮され、各入れ子４〜１２の先端の接触圧は、１０２９〜１４６６ｋｇ／ｃｍ²の範囲であり、比較的ばらつきが少ない。
【００３８】
【表４】

本例では、入れ子５，７を他の入れ子４，６，８〜１２よりも１５℃高く温度制御しているが、各入れ子４〜１２をさらに細かく温度制御することにより、接触圧のばらつきをもっとなくすことができる。例えば、入れ子４，８の温度も独立して制御すれば、さらに接触圧のばらつきを小さくしてバリの発生を防げることが明らかである。
【００３９】
このように各入れ子４〜１２の温度を独立して制御することは、前記の通り、水管１８ａ〜１８ｅに流入する流体の温度を調整するなどの方法で容易に行え、温度の上下は自在に行え、微調整も容易であるので、成形を行いながらバリの発生が最も抑えられるように試行錯誤的に各入れ子４〜１２の温度を設定することができる。
【００４０】
以上、模式的な計算例を示したが、これは、分割された複数の入れ子を独立して温度制御することによって、接触圧を概ね均等に高い値にすることができることを証明するものである。ただし、前記した各計算例の具体的な数値等は、本発明を何ら限定するものではなく、各入れ子および母型の大きさ、形状、材質などや、型締め機構の性能や、成形材料の種類や、成形を行う環境など様々な要因に応じて、適宜最適な温度制御を行うようにすればよい。
【００４１】
以上説明した本発明の実施形態では、各入れ子４〜１２に水管１８ａ〜１８ｅを設けているが、前記した通り、水管の個数と位置は任意に設定することができる。そして、この水管に供給される温度制御用の流体としては、過熱蒸気、飽和蒸気、加圧水、熱水、温水、冷水などを、自由に選択することができる。
【００４２】
また、各入れ子４〜１２の温度制御は、前記したように水管１８ａ〜１８ｅに過熱蒸気、飽和蒸気、加圧水、熱水、温水、冷水などの流体を供給する方法に限られず、電気ヒータやペルチェ素子のような様々な加熱冷却源を用いるなど、あらゆる方法を採用することができる。また、入れ子に水管を設けることができない場合には、断熱層１９をなくして、母型３に設けた水管（図示せず）により入れ子４〜１２を温度制御してもよい。その場合には、各入れ子４〜１２に近接する水管をそれぞれ独立させて異なる流体を供給できる構成にするなど、各入れ子４〜１２を独立して温度制御できる構成にする。
【００４３】
本発明は、射出成形法、トランスファ成形法、圧縮成形法、反応射出成形法、ブロー成形法、熱成形法など、様々な方式の成形方法に適用できる。そして、この成形方法に使用される成形材料としては、熱可塑性樹脂、熱硬化性樹脂、およびこれらのアロイやフィラー配合物が用いられる。
【００４４】
なお、前記した実施形態では、固定側金型と可動側金型の両方とも入れ子式にして、可動側金型の入れ子１７のみ分割された構成にしている。しかし、固定側金型と可動側金型のいずれか一方のみを入れ子式にして、その入れ子を複数に分割した構成にすることもできる。また、固定側金型と可動側金型の両方とも入れ子式にして、両方の入れ子２，１７を複数に分割した構成にしても、固定側金型の入れ子２のみ分割された構成にしてもよい。いずれの場合も、複数に分割された入れ子のうちの少なくとも１つを、その他の入れ子に対して独立して温度制御する構成にする。なお、各入れ子の材質は、同じであっても異なっていてもよい。
【００４５】
前記したような、金型構成の様々な例について、概略図である図５〜７を参照して具体的に説明する。
【００４６】
図５に示す構成では、一方の金型３０の母型３１に装着される入れ子３２が複数に分割されている。そして、この複数の入れ子３２ａ〜３２ｆのうちの入れ子３２ｂ，３２ｅが温調器３３に接続されて１つの温度制御系統を構成し、その他の入れ子３２ａ，３２ｃ，３２ｄ，３２ｆがもう１つの温調器３４に接続されてもう１つの温度制御系統を構成しており、同一の母型３１に装着されている入れ子３２のうちの一部が、その他の入れ子に対して独立して温度制御される。これに対し、他方の金型３５の母型３６には、分割されていない単一の入れ子３７が装着されている。そしてこの入れ子３７は別の温調器３８に接続されて別の温度制御系統を構成している。
【００４７】
この構成では、両金型３０，３５の入れ子３２ａ〜３２ｆ，３７が、合計３つの温度制御系統を構成している。これら３つの温度制御系統のすべてが、各入れ子３２ａ〜３２ｆ，３７をそれぞれの所定の温度に実質的に一定に保つように温度制御する、いわゆる通常成形法を行うものであってもよく、各入れ子３２ａ〜３２ｆ，３７のキャビティ表面の温度を繰り返し上下させるヒートサイクル法を行うものであってもよい。また、これら３つの温度制御系統のうちのいずれか１つまたは２つがヒートサイクル法を行うものであり、残りの温度制御系統が温度一定であってもよい。
【００４８】
図６に示す構成では、一方の金型３０の構成が、図５に示す構成と全く同一であり、他方の金型３５の母型３６に装着される入れ子３９も複数に分割されている。そして、この複数の入れ子３９ａ〜３９ｆは、全て温調器３８に接続されて温度制御系統を構成している。この構成でも、両金型３０，３５の入れ子３２ａ〜３２ｆ，３９ａ〜３９ｆが、合計３つの温度制御系統を構成している。これら３つの温度制御系統のすべてが、いわゆる通常成形法を行うものであってもよく、ヒートサイクル法を行うものであってもよい。また、これら３つの温度制御系統のうちのいずれか１つまたは２つがヒートサイクル法を行うものであり、残りの温度制御系統が温度一定であってもよい。
【００４９】
図７に示す構成では、一方の金型３０の構成が、図５に示す構成と全く同一であり、他方の金型３５の母型３６に装着される入れ子３９は、図６に示す構成と同様に複数に分割されている。そのうちの一部の入れ子３９ｂ，３９ｅが温調器４０に接続されて１つの温度制御系統を構成し、その他の入れ子３９ａ，３９ｃ，３９ｄ，３９ｆがもう１つの温調器４１に接続されてもう１つの温度制御系統を構成しており、各温度制御系統ごとに独立して温度制御されている。すなわち、金型３０の入れ子３２と同様に、金型３５の入れ子３９も、複数の温度制御系統ごとに独立して温度制御される。なお、４つの温度制御系統のすべてが、いわゆる通常成形法を行うものであってもよく、ヒートサイクル法を行うものであってもよい。また、これら４つの温度制御系統のうちのいずれか１つ、２つ、または３つがヒートサイクル法を行うものであり、残りの温度制御系統が温度一定であってもよい。
【００５０】
図７に示す例では、金型３５に設けられた温度制御系統（温調器）の数が、金型３０に設けられた温度制御系統（温調器）の数と一致し、入れ子３９ａ〜３９ｆを複数の温度制御系統に分けるパターンが、入れ子３２ａ〜３２ｆを複数の温度制御系統に分けるパターンと一致しているが、金型３０と金型３５とで温度制御系統の数が異なっていたり、入れ子３２ａ〜３２ｆと入れ子３９ａ〜３９ｆとで、複数の温度制御系統に分けるパターンが異なっていても構わない。
【００５１】
以上、本発明を適用可能な様々な金型構成について、図５〜７を参照して説明したが、入れ子３２，３９の分割数や温度制御系統の数などは、これらの例に限定されることなく自由に設計することができる。また、金型３０，３５のいずれが可動側であっても構わない。
【００５２】
【発明の効果】
複数に分割された入れ子を独立して温度制御することにより、樹脂充填時の各入れ子の温度を微調整して、バリの発生を抑えることができる。容易かつ可逆的に各入れ子の微調整が可能であるため、最適な温度条件を試行錯誤的に求めることができ、また、成形中にバリの発生状況が変化した際にも即座に対応できるなど、従来の成形方法に比べてバリ防止の効果が非常に大きい。特に、比較的高温になって通常はバリの生じ易いヒートサイクル法において、本発明は極めて効果的である。
【図面の簡単な説明】
【図１】従来の、ヒートサイクル成形法が適用される合成樹脂成形用金型装置の一例を示す断面図である。
【図２】従来の金型装置の可動側金型の平面図である。
【図３】図２に示す金型装置のＡ−Ａ’線断面図である。
【図４】本発明の成形方法を行う金型装置の断面図である。
【図５】本発明の成形方法が適用可能な金型装置の例を示す概略図である。
【図６】本発明の成形方法が適用可能な金型装置の他の例を示す概略図である。
【図７】本発明の成形方法が適用可能な金型装置のさらに他の例を示す概略図である。
【符号の説明】
１ 固定側金型の母型
２ 固定側金型の入れ子
３ 可動側金型の母型
４〜１２ 複数に分割された入れ子（可動側）
１３ キャビティ
１４ ピン
１５ キャビティ周縁部
１６ キャビティ周縁部の外側の部分
１７ 可動側金型の入れ子
１８ａ〜１８ｅ 水管
１９ 断熱層
３０ 一方の金型
３１，３６ 母型
３２，３７，３９ 入れ子
３２ａ〜３２ｆ，３９ａ〜３９ｆ 複数に分割された入れ子
３３，３４，３８，４０，４１ 温調器
３５ 他方の金型[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for molding a synthetic resin, and more particularly to a method for controlling the temperature of a mold for molding a synthetic resin suitable for a heat cycle method in which a cavity surface is alternately heated and cooled.
[0002]
[Prior art]
When filling the mold cavity with molten resin in injection molding of thermoplastic resin, if the mold temperature is high, the fluidity of the resin is good, so that the transfer of the cavity surface is good and the weld line is not noticeable. Therefore, a heat cycle method in which the cavity surface is heated only while the molten resin is filled in the cavity has been put into practical use.
[0003]
The present applicant previously proposed a synthetic resin molding die apparatus to which the heat cycle molding method is applied as shown in FIG. 1 according to Japanese Patent Application No. 11-375069 (Japanese Patent Laid-Open No. 2001-18229). Yes.
[0004]
This synthetic resin molding die apparatus includes a mother die 21 and a nest 22 incorporated therein. A cavity surface 23 is formed in the nest 22, and in the vicinity of the cavity surface 23, a water pipe 24 into which a heating medium and a cooling medium are alternately introduced is provided. A heat insulating layer 25 made of air or a material having low heat conductivity is provided between the insert 22 and the mother die 21.
[0005]
When the heat cycle molding method is performed using this mold apparatus, burrs tend to be easily generated around the molded product. The burr is generated when the resin penetrates between the contact surfaces of both inserts 22 and solidifies in a so-called parting line where the inserts of the fixed mold and the movable mold come into contact. Further, as shown in FIGS. 2 and 3 to be described later, a molded product having a window portion formed by using a nest 17 having pins 14 standing in the cavity 13 includes not only the periphery of the molded product but also a window. The burr is also conspicuous in the part. That is, in order to mold a molded article having a window portion, a nest 17 in which a pin 14 stands inside the cavity 13 is used. However, the resin has a tip portion of the pin 14 and a cavity surface of the nest 2 opposed thereto. As a result of intrusion and solidification during the period, burrs are generated inside the window.
[0006]
In general, in the normal molding method in which the resin is filled while keeping the cavity temperature constant at a low temperature, the temperature of the insert itself is low, and the tip portion of the resin flowing in the cavity formed in the insert is cooled to reduce the viscosity. Since it is high, the resin that has reached the parting line is unlikely to enter between the contact surfaces of both inserts, and burrs are unlikely to occur. However, in the heat cycle molding method described above, the cavity surface temperature is increased during resin filling (for example, the temperature during resin filling is approximately 120 ° C.), and the tip portion of the resin flowing in the cavity is difficult to cool and has a viscosity. Therefore, the resin that has reached the parting line is likely to enter between the contact surfaces of both inserts. For this reason, burrs are more likely to occur in the heat cycle molding method than in the normal molding method.
[0007]
Usually, in order to prevent the occurrence of burrs in the injection molding method, it is effective to increase the contact pressure of both nestings in the parting line, increase the contact pressure using a molding machine with a large mold closing force, Even in a molding machine having the same mold closing force, the contact pressure is increased by reducing the contact area of both inserts in the parting line. For example, in the configuration shown in FIG. 3 to be described later, the cavity peripheral edge 15 corresponding to the outer periphery of the molded product is formed higher than the outer portion 16 thereof. Only the pin 14 has a small contact area, so that the contact pressure is high, and the possibility that the resin enters between the contact surfaces to generate burrs is reduced. However, with this configuration alone, as described above, burrs may occur not only around the molded product but also inside the window portion. Therefore, in the case where burrs are conspicuous on the inside of the window portion as compared with the periphery of the molded product, the pin 14 for forming the window portion is made higher than the cavity peripheral portion 15, and the contact pressure of the pin 14 is made higher This prevents burrs inside the window.
[0008]
[Problems to be solved by the invention]
When burrs are generated, as described above, the contact pressure between the peripheral edge of the cavity and the pins is increased to prevent burrs. However, depending on the shape of the molded product, in at least one of the fixed side mold and the movable side mold, there is a case where the nesting to be mounted on the mother mold needs to be divided into a plurality of parts. In the mold having the structure divided into two, there was a situation where the generation of burrs could not be prevented. The situation will be specifically described with reference to FIGS.
[0009]
FIG. 2 is a plan view of a movable mold of a mold apparatus that molds two products at a time, and FIG. 3 is a cross-sectional view taken along the line AA ′ of FIG. In the mold apparatus shown in FIGS. 2 and 3, the insert 2 attached to the fixed mold 1 is not divided, but only the insert 17 attached to the movable mold 3 is divided. It has a configuration. The movable mold nest 17 is composed of finely divided nests 4 to 12, and is formed with a cavity 13 in which a molded product is molded by being filled with resin, and a window portion of the molded product standing in the cavity. It has the pin 14 to do.
[0010]
In the mold apparatus having such a configuration, first, the pin 14 for forming the window portion and the entire nest outside the cavity are formed at the same height. Burrs occurred. As described above, in order to reduce the total contact area of the insert 17 and increase the contact pressure, the majority of the contact surface of the insert 17 is scraped so that the cavity peripheral edge 15 is higher than the outer portion 16. The burr around the molded product was reduced, but the burr inside the window was still large. Therefore, when the pin 14 forming the window portion was made relatively higher than the cavity peripheral edge portion 15, the burrs inside the window portions disappeared, but the burrs around the molded product became severe again. On the other hand, when the pin 14 of the window portion was slightly shaved, the burr around the product was reduced, but the burr of the window portion became worse again.
[0011]
As described above, the height of the cavity peripheral edge 15 and the pin 14 is correlated with the state of burrs around the molded product and the inside of the window. The occurrence is slightly different for each of the nestings 4-12. Therefore, it is very difficult to find the optimum height of the peripheral edge 15 of the cavity and the height of the pin 14 so that no burrs around the molded product and burrs inside the window portion are generated. The height adjustment of the contact surfaces of the nestings 4 to 12 has not been easy due to the problem of the accuracy of the contact surface height adjustment and workability. Actually, while recognizing the necessity of fine adjustment of the height of each contact surface of each nesting 4-12, considering the work efficiency etc., the halfway state where only insufficient adjustment has been made Production had to start as it was. In addition, during the production of molded products, even if the molding equipment and working conditions were not changed, the burrs could change over time. Thus, the height of the contact surface of each nesting 4 to 12 cannot be adjusted, and once adjusted, it is difficult to change the contact surface. Can not.
[0012]
Therefore, the object of the present invention is to prevent the occurrence of burrs in each part even when the nesting is divided into a plurality of parts, particularly when the heat cycle method is performed, and also during the production process. An object of the present invention is to provide a molding method capable of appropriately performing fine adjustment for preventing the occurrence.
[0013]
[Means for Solving the Problems]
A feature of the present invention is that a mold apparatus in which a nest attached to at least one of a movable mold and a fixed mold is divided into a plurality of molds is used. To produce a molded product having a window In the molding method, the plurality of nestings mounted on the same matrix are divided into a plurality of temperature control systems, and the temperature control is independently performed for each temperature control system. Of the plurality of nestings, the nesting having a pin for forming the window portion is made different in temperature from the other nestings when the resin is filled. By the way. Each nest is kept at a constant temperature, or its cavity surface temperature is raised or lowered by a heat cycle method.
[0014]
When only the nest attached to one of the movable mold and the fixed mold is divided into a plurality of parts and the temperature is controlled by the method described above, the mold of the other mold is A single nesting that is not divided may be mounted. In that case, even if the single nesting of the other mold is kept at a constant temperature, the cavity surface temperature may be increased or decreased by a heat cycle method.
[0015]
In addition, when the inserts to be mounted on both the movable mold and the fixed mold are divided into a plurality of molds, the temperature of both mold inserts is controlled by the method described above. May be. Alternatively, only the nesting of one mold may be temperature controlled by the above-described method, and the plurality of nestings of the other mold may be temperature controlled in the same manner. In the latter case, the cavity surface temperature may be increased or decreased by a heat cycle molding method even if the plurality of inserts of the other mold are kept at a constant temperature.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
The mold apparatus of this embodiment is the same as the conventional mold apparatus shown in FIGS. This is a mold apparatus that molds two molded products at a time. The insert 2 attached to the fixed mold 1 is not divided, and the insert 2 is attached to the movable mold 3. Only 17 are divided. A cross-sectional view of the mold apparatus of this embodiment is shown in FIG. 4, and a plan view of the movable side mold is substantially the same as FIG. 2, and is omitted here. 2 and FIG.
[0018]
A movable mold insert 17 constituted by the finely divided inserts 4 to 12 has a cavity 13 and a pin 14 standing in the cavity. In order to increase the contact pressure, the cavity peripheral edge portion 15 is higher than the outer portion 16 thereof. Between each of the inserts 4 to 12 and the mother die 3, a heat insulating layer 19 having a low thermal conductivity such as an air layer held in a recess is provided. The heat insulation layer 19 reduces the influence of heat transfer and temperature difference between the nestings 4 to 12 and the mother die 3.
[0019]
The nests 4 to 12 are provided with water pipes 18a to 18e, respectively. The water pipes 18a to 18e corresponding to the nests do not communicate with each other, and constitute separate circulation flow paths. The water pipes 18a to 18e may all be connected to different fluid supply sources to form a circulation flow path, respectively, but the water pipes 18a to 18e are divided into several (at least two) groups (temperature control systems), It may be connected to a fluid supply source for each group (for each temperature control system) to constitute a circulation flow path. In FIG. 4, five water pipes 18 a to 18 e are shown for convenience, but any number and arrangement of water pipes can be formed according to the number of divisions of the nest 17, the shape and arrangement thereof, and the like. . In some cases, the water pipes do not necessarily have to be provided in all of the nests 4 to 12 divided into a plurality of parts. However, in the present invention, all the nestings 4 to 12 are not provided with water pipes of the same system (which constitute the same circulation flow path).
[0020]
In the present embodiment, the temperatures of the nestings 4 to 12 are controlled by flowing fluids such as superheated steam, saturated steam, pressurized water, hot water, hot water, and cold water into the water pipes 18a to 18e. At least one of the twelve (eg, nesting 5, 7) is temperature controlled independently of the other nesting (eg, nesting 4, 6, 8-12). That is, the temperature of the water pipe provided in at least one of the nestings 4 to 12 (for example, the nestings 5 and 7) and the water pipe provided in the other nestings (for example, the nestings 4, 6, 8 to 12) Flows in different fluids. The “fluids with different temperatures” mentioned here may be the same type of fluid and different temperatures (for example, high-temperature saturated steam and low-temperature saturated steam), or different types of fluid with different temperatures. May be different (for example, saturated steam and hot water).
[0021]
The temperature control is performed so as to finely adjust the temperature difference between the nestings 4 to 12 with reference to thermometers arranged in the nestings 4 to 12 (not shown). For example, as described above, the temperature difference between the nestings 5 and 7 and the other nestings 4, 6, and 8 to 12 is adjusted, and if necessary, the nestings 4, 6, and 8 to 12 around the cavity 13 are adjusted. Also finely adjust the temperature difference between each other. As a result, each insert is expanded and contracted, and the same effect as that obtained by finely adjusting the height of each part of the pin 14 and the cavity peripheral part 15 can be obtained. Occurrence can be suppressed.
[0022]
When the height of each part such as the cavity peripheral edge 15 and the pin 14 is adjusted by machining as in the prior art, it is extremely difficult to make fine adjustments by trial and error. It is impossible to restore it. Moreover, it is necessary to disassemble the mold apparatus once and perform machining for each nesting. Therefore, even if an environmental change such as a temperature rise with time occurs during the molding process and the state of occurrence of burrs changes, it is not possible to respond flexibly.
[0023]
On the other hand, in the present invention, by adjusting the temperature of the fluid flowing into the water pipes 18a to 18e, the temperature of each nesting 4 to 12 can be easily and reversibly adjusted. It is possible to make fine adjustments appropriately while confirming the occurrence status of burrs, and to prevent the occurrence status of burrs from changing over time. According to this, unlike the conventional adjustment of the height of the contact surface by machining, finer fine adjustment can be performed very easily without disassembling the mold apparatus. It is preferable to perform trial molding before mass production, determine the temperature of each nesting 4 to 12 where the occurrence of burrs is most suppressed, and perform production while holding each nesting 4 to 12 at that temperature, More preferably, the temperature of each nesting 4 to 12 is finely adjusted as appropriate while monitoring the occurrence of burrs during production.
[0024]
As described above, since the surface temperature of the cavity 13 is increased when the resin is filled, and the tip portion of the resin flowing in the cavity 13 is difficult to cool and has a low viscosity, it reaches the parting line. The effect of raising and lowering the temperature of the nestings 4 to 12 needs to take this influence into consideration because the obtained resin easily enters between the contact surfaces of the nesting. Each of the nestings 4 to 12 may be kept at a constant temperature even if a heat cycle method in which the temperature rise and the temperature fall are repeated is performed. Moreover, you may perform a heat cycle method to only some of the nestings 4-12 divided | segmented into plurality. Thus, the method of the present invention is effective even when the temperature of each of the nestings 4 to 12 is increased or decreased by the heat cycle method or is kept constant. Since the present invention aims to prevent burrs, the temperature of nesting during resin filling is controlled when the heat cycle method is performed.
[0025]
Further, as described above, the method of the present invention is effective even when the pin 14 is made higher than the cavity peripheral edge 15 or when the pin 14 is made the same height as the cavity peripheral edge 15.
[0026]
The fact that the effect of preventing the occurrence of burrs can be obtained in the same manner as the fine adjustment of the heights of the pin 14 and the cavity peripheral edge 15 by the molding method of the present invention described above is schematically calculated as a metal compression phenomenon. A supplementary explanation will be given using the results obtained.
[0027]
In calculation, in a nested mold apparatus as shown in FIGS. 2 and 4, the thickness of the molded product is 2.5 mm, the thickness of the nesting 4 to 12 is 40 mm, and the area of each part of the nesting 4 to 12 is As shown in Table 1.
[0028]
[Table 1]

The mold closing force is 150 t, and the resin pressure in the mold is 400 kg / cm. ² The longitudinal elastic modulus of the nesting 4 to 12 is 2.1 × 10 ^-6 kg / cm ² It was. The position is based on the tip of the insert 4 (tip of the cavity peripheral edge 15) when the mold is opened.
[0029]
[Calculation Example 1]
First, calculation is performed for the case where the cavity peripheral edge 15 and the height of the pin 14 are adjusted as in the conventional case.
[0030]
In this example, in order to prevent the burr | flash inside a window part, the case where the pin 14 for forming a window part was made higher than the cavity peripheral part 15, and the contact pressure of the pin 14 was raised was considered. Specifically, using the height of the cavity peripheral edge 15 of the insert 4 as a reference (0), the height of the cavity peripheral edge 15 of the inserts 6 and 8 to 12 is made to coincide with that, and the height of the pins 14 of the inserts 5 and 7 is increased. The thickness was set to +10 μm. In this case, as shown in Table 2, at the time of resin filling, each nest is compressed so as to move backward by 2.51 μm.
[0031]
[Table 2]

When the resin is filled, the contact pressure at the tip of the cavity peripheral edge 15 of the inserts 4 and 8 is 1157 kg / cm. ² The contact pressure at the tip of the pin 14 of the nesting 5 and 7 is 1751 kg / cm. ² In these nestings, no burrs are generated. However, the contact pressure at the tip of the cavity peripheral edge 15 of the insert 6 is 770 kg / cm. ² The contact pressure at the tip of the cavity peripheral edge 15 of the inserts 9 to 12 is 786 kg / cm. ² Therefore, the contact pressure is insufficient in these nesting portions 6, 9 to 12, and burrs are likely to occur.
[0032]
[Calculation Example 2]
Therefore, a method for suppressing the occurrence of burrs by finely adjusting the heights of the cavity peripheral edge 15 and the pin 14 was studied.
[0033]
That is, the height of the cavity peripheral edge 15 of the insert 4 is set as a reference (0), the height of the cavity peripheral edge 15 of the insert 8 is matched with that, and the height of the pins 14 of the inserts 5 and 7 is +7.80 μm. The height of the cavity peripheral edge 15 of the insert 6 was set to +0.91 μm, and the height of the cavity peripheral edge 15 of the inserts 9 to 12 was set to +0.83 μm. In this case, as shown in Table 3, at the time of resin filling, each nest is compressed so as to move backward by 2.63 μm, and the contact pressure at the tip of each nest is 1177 kg / cm. ² Becomes uniform.
[0034]
[Table 3]

Therefore, in this case, it can be seen that the occurrence of burrs can be suppressed by fine adjustment of the height, and at the same time, the contact pressure fluctuates greatly with a height difference of only a few μm compared with the result of calculation example 1. I understand. That is, it is understood that how the burrs around the window portion and the molded product differ greatly depending on the height (for example, on the order of 0.1 μm) of the pin 14 and the cavity peripheral portion 15.
[0035]
As described above, it has been found that the occurrence of burrs can be suppressed in the calculation, but it is extremely difficult to accurately adjust the height of the cavity peripheral edge 15 and the pin 14 to the order of 0.1 μm or less because of machining. It is very difficult work. When comparing calculation examples 1 and 2, it is clear that the contact pressure varies greatly and causes burrs even if there is very little error. Therefore, it can be said that it is a very difficult method in practice.
[0036]
In addition, as described above, the fine adjustment of the height of each nesting by such machining is irreversible and difficult to readjust. There is an inconvenience that it cannot cope with the change of the occurrence situation.
[0037]
[Calculation Example 3]
Next, the case where the present invention was adopted and the temperature of each nesting was finely adjusted independently was examined. The heights of the cavity peripheral edge 15 and the pin 14 of each of the inserts 4 to 12 are all made equal, and the temperature at the time of resin filling of the inserts 5 and 7 is set to 15 than the temperature at the time of resin filling of the inserts 4, 6 and 8 to 12 The temperature was raised. According to this, at the time of resin filling, each nest is compressed so as to move backward by 10.17 μm, and the contact pressure at the tip of each nest 4 to 12 is 1029 to 1466 kg / cm. ² There is relatively little variation.
[0038]
[Table 4]

In this example, the nestings 5 and 7 are temperature-controlled 15 ° C. higher than the other nestings 4, 6, and 8 to 12. More can be eliminated. For example, if the temperatures of the nestings 4 and 8 are also controlled independently, it is clear that the variation in contact pressure can be further reduced to prevent the generation of burrs.
[0039]
As described above, the temperature of each of the nestings 4 to 12 can be controlled independently by adjusting the temperature of the fluid flowing into the water pipes 18a to 18e as described above. Since it can be performed and fine adjustment is easy, the temperature of each of the nestings 4 to 12 can be set by trial and error so that the generation of burrs is minimized while forming.
[0040]
In the above, a schematic calculation example has been shown, but this proves that the contact pressure can be increased to a substantially uniform value by independently controlling the temperature of the plurality of divided nestings. . However, the specific numerical values of each calculation example described above do not limit the present invention at all, and the size, shape, material, etc. of each nesting and mother mold, the performance of the clamping mechanism, and the molding material Optimum temperature control may be appropriately performed according to various factors such as the type and the molding environment.
[0041]
In the embodiment of the present invention described above, the water pipes 18a to 18e are provided in the nestings 4 to 12, but the number and position of the water pipes can be arbitrarily set as described above. The temperature control fluid supplied to the water pipe can be freely selected from superheated steam, saturated steam, pressurized water, hot water, hot water, cold water, and the like.
[0042]
The temperature control of each nesting 4-12 is not limited to the method of supplying fluid such as superheated steam, saturated steam, pressurized water, hot water, hot water, cold water, etc. to the water pipes 18a-18e as described above. Any method can be employed, such as using various heating and cooling sources such as elements. Further, when the water pipe cannot be provided in the nest, the temperature of the nests 4 to 12 may be controlled by a water pipe (not shown) provided in the mother die 3 without the heat insulating layer 19. In that case, the temperature of each nesting 4-12 can be controlled independently, for example, the water pipes adjacent to each nesting 4-12 can be made independent to supply different fluids.
[0043]
The present invention can be applied to various types of molding methods such as injection molding, transfer molding, compression molding, reaction injection molding, blow molding, and thermoforming. And as a molding material used for this shaping | molding method, a thermoplastic resin, a thermosetting resin, and these alloys and filler compounds are used.
[0044]
In the above-described embodiment, both the stationary mold and the movable mold are nested, and only the movable mold mold 17 is divided. However, only one of the fixed side mold and the movable side mold can be nested, and the nested structure can be divided into a plurality of parts. In addition, both the fixed side mold and the movable side mold are nested, and both the nestings 2 and 17 are divided into a plurality of parts, or only the fixed side mold nesting 2 is divided. Good. In any case, at least one of the nestings divided into a plurality of nestings is configured to control the temperature independently of the other nestings. In addition, the material of each nesting may be the same or different.
[0045]
Various examples of the mold configuration as described above will be specifically described with reference to FIGS.
[0046]
In the configuration shown in FIG. 5, the insert 32 to be mounted on the mother die 31 of one mold 30 is divided into a plurality of pieces. Of the plurality of nests 32a to 32f, nests 32b and 32e are connected to the temperature controller 33 to constitute one temperature control system, and the other nests 32a, 32c, 32d and 32f are another temperature control. Is connected to the container 34 to form another temperature control system, and a part of the inserts 32 mounted on the same mother die 31 is temperature controlled independently of the other inserts. . On the other hand, a single nesting 37 that is not divided is attached to the mother die 36 of the other die 35. The insert 37 is connected to another temperature controller 38 to form another temperature control system.
[0047]
In this configuration, the nestings 32a to 32f and 37 of both molds 30 and 35 constitute a total of three temperature control systems. All of these three temperature control systems may perform a so-called normal molding method in which the temperature is controlled so as to keep each nesting 32a to 32f, 37 substantially constant at a predetermined temperature. The heat cycle method of repeatedly raising and lowering the temperature of the cavity surfaces of the nestings 32a to 32f and 37 may be performed. Further, any one or two of these three temperature control systems may perform the heat cycle method, and the remaining temperature control systems may have a constant temperature.
[0048]
In the configuration shown in FIG. 6, the configuration of one mold 30 is exactly the same as the configuration shown in FIG. 5, and the insert 39 attached to the mother mold 36 of the other mold 35 is also divided into a plurality. The plurality of inserts 39a to 39f are all connected to the temperature controller 38 to constitute a temperature control system. Even in this configuration, the nestings 32a to 32f and 39a to 39f of both molds 30 and 35 constitute a total of three temperature control systems. All of these three temperature control systems may perform a so-called normal molding method or may perform a heat cycle method. Further, any one or two of these three temperature control systems may perform the heat cycle method, and the remaining temperature control systems may have a constant temperature.
[0049]
In the configuration shown in FIG. 7, the configuration of one mold 30 is exactly the same as the configuration shown in FIG. 5, and the insert 39 attached to the mother mold 36 of the other mold 35 has the configuration shown in FIG. 6. Similarly, it is divided into a plurality of parts. Some of the inserts 39b and 39e are connected to the temperature controller 40 to form one temperature control system, and the other inserts 39a, 39c, 39d, and 39f are connected to the other temperature controller 41. One temperature control system is configured, and the temperature is controlled independently for each temperature control system. That is, similarly to the insert 32 of the mold 30, the insert 39 of the mold 35 is temperature-controlled independently for each of a plurality of temperature control systems. All of the four temperature control systems may perform a so-called normal molding method or may perform a heat cycle method. Further, any one, two, or three of these four temperature control systems may perform the heat cycle method, and the remaining temperature control systems may have a constant temperature.
[0050]
In the example shown in FIG. 7, the number of temperature control systems (temperature controllers) provided in the mold 35 matches the number of temperature control systems (temperature controllers) provided in the mold 30, and the inserts 39 a to 39 a. The pattern for dividing 39f into a plurality of temperature control systems is the same as the pattern for dividing the nestings 32a to 32f into a plurality of temperature control systems, but the number of temperature control systems for the mold 30 and the mold 35 is different. The patterns divided into the plurality of temperature control systems may be different between the nestings 32a to 32f and the nestings 39a to 39f.
[0051]
As described above, various mold configurations to which the present invention can be applied have been described with reference to FIGS. 5 to 7. However, the number of nestings 32 and 39, the number of temperature control systems, and the like are limited to these examples. It can be designed freely without any problems. Further, either of the molds 30 and 35 may be the movable side.
[0052]
【The invention's effect】
By independently controlling the temperature of the nesting divided into a plurality of parts, the temperature of each nesting during resin filling can be finely adjusted to suppress the occurrence of burrs. Easy and reversible adjustment of each nesting is possible, so the optimum temperature condition can be obtained by trial and error, and it is possible to respond immediately when burrs are changed during molding. Compared with conventional molding methods, the effect of preventing burrs is very large. In particular, the present invention is extremely effective in a heat cycle method in which burrs are usually generated at a relatively high temperature.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of a conventional mold apparatus for molding a synthetic resin to which a heat cycle molding method is applied.
FIG. 2 is a plan view of a movable mold of a conventional mold apparatus.
3 is a cross-sectional view taken along line AA ′ of the mold apparatus shown in FIG. 2. FIG.
FIG. 4 is a sectional view of a mold apparatus for performing the molding method of the present invention.
FIG. 5 is a schematic view showing an example of a mold apparatus to which the molding method of the present invention can be applied.
FIG. 6 is a schematic view showing another example of a mold apparatus to which the molding method of the present invention can be applied.
FIG. 7 is a schematic view showing still another example of a mold apparatus to which the molding method of the present invention can be applied.
[Explanation of symbols]
1 Master mold of fixed mold
2 Nest of fixed mold
3 Mold of movable side mold
4-12 Nest divided into multiple parts (movable side)
13 cavity
14 pin
15 Cavity edge
16 Outside part of cavity periphery
17 Nest of movable mold
18a-18e water pipe
19 Thermal insulation layer
30 One mold
31, 36
32, 37, 39 nested
32a to 32f, 39a to 39f Nesting divided into a plurality of parts
33, 34, 38, 40, 41 Temperature controller
35 The other mold

Claims (9)

In a molding method for manufacturing a molded article having a window portion using a mold apparatus in which a nest attached to at least one mother mold of a movable mold and a fixed mold is divided into a plurality of parts,
Dividing the plurality of nestings mounted on the same matrix into a plurality of temperature control systems, and independently controlling the temperature for each temperature control system ,
A molding method characterized in that , among a plurality of the nests, a nest having a pin for forming the window portion is made different in temperature from the other nests during resin filling . The molding method according to claim 1, wherein the temperature is controlled so as to keep the nests substantially constant at respective predetermined temperatures in all the temperature control systems. The molding method according to claim 1, wherein a heat cycle method of repeatedly raising and lowering the temperature of the surface of the nesting cavity is performed by at least one of the plurality of temperature control systems. The molding method according to claim 3 , wherein the temperature at the time of resin filling of the nesting in which the temperature of the cavity surface is repeatedly increased and decreased is controlled independently for each temperature control system . One of the movable mold and the fixed mold is fitted with a divided nest, and the other mold is fitted with a single non-divided nest. In a molding method using a mold apparatus,
In said one metal mold | die, temperature control is performed according to the shaping | molding method of any one of Claims 1-4,
The molding method is characterized in that the nesting of the other mold is temperature-controlled by another temperature control system so as to be kept substantially constant at a predetermined temperature. One of the movable mold and the fixed mold is fitted with a divided nest, and the other mold is fitted with a single non-divided nest. In a molding method using a mold apparatus,
In said one metal mold | die, temperature control is performed according to the shaping | molding method of any one of Claims 1-4,
A molding method characterized by performing a heat cycle method in which the temperature of the cavity surface is repeatedly raised and lowered by another temperature control system in the other mold nesting. In the molding method using a mold apparatus in which both the movable mold and the fixed mold are divided into a plurality of inserts to be mounted on the mother mold,
The molding method according to any one of claims 1 to 4, wherein temperature control is performed in both the movable mold and the fixed mold. In the molding method using a mold apparatus in which both the movable mold and the fixed mold are divided into a plurality of inserts to be mounted on the mother mold,
In any one mold, temperature control is performed according to the molding method according to any one of claims 1 to 4,
A molding method characterized in that the plurality of nestings of the other mold are temperature-controlled so as to be kept substantially constant at a predetermined temperature by another temperature control system. In the molding method using a mold apparatus in which both the movable mold and the fixed mold are divided into a plurality of inserts to be mounted on the mother mold,
In any one mold, temperature control is performed according to the molding method according to any one of claims 1 to 4,
A molding method characterized by performing a heat cycle method in which the temperature of the cavity surface is repeatedly raised and lowered by another one temperature control system for the plurality of nestings of the other mold.

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