JP4266274B2

JP4266274B2 - Injection molding method

Info

Publication number: JP4266274B2
Application number: JP2000252736A
Authority: JP
Inventors: 富男飯野; 秀中井
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2000-08-23
Filing date: 2000-08-23
Publication date: 2009-05-20
Anticipated expiration: 2020-08-23
Also published as: JP2002067069A

Description

【０００１】
【発明の属する技術分野】
本発明は、単一の型締め装置で型締めされる３個の金型を用いる射出成形方法に関する。
【０００２】
【従来の技術】
従来、単一の型締め装置で型締めされる３個の金型を用いる射出成形方法として、３個の金型のうちキャビティ容積が最大の第１の金型に対して溶融樹脂の射出充填を行う第１の射出機と、第１の金型以外の第２と第３の２個の金型に対して溶融樹脂の射出充填を行う第２の射出機とを用いて、各金型に対し同時に溶融樹脂を射出充填して、射出成形に要する時間を短縮するものが知られている。
【０００３】
【発明が解決しようとする課題】
上記の射出成形方法では、各金型に対する射出充填時の型締めに要する型締め力の夫々を合計したものを型締め力として発生できる強大な型締め装置が必要となり、成形製品の大きさや形状によって成形が困難になる場合が生じるうえ、強大な型締め力を発生できる型締め装置を新規に調達する場合、コストアップの要因となる。
【０００４】
本発明は、上記問題点に鑑み、型締め装置の型締め力を抑制できて、単一の型締め装置で型締めされる３個の金型を用いて能率的に射出成形を行うことができる方法を提供することを課題としている。
【０００５】
【課題を解決するための手段】
上記課題を解決するため、単一の型締め装置で型締めされる３個の金型を用いる射出成形方法において、本発明の第１の特徴によれば、３個の金型のうちキャビティ容積が最大の第１の金型に対して溶融樹脂の射出充填を行う第１の射出機と、第１の金型以外の第２と第３の２個の金型に対して溶融樹脂の射出充填を行う第２の射出機と、第２の射出機から射出される溶融樹脂を第２と第３の両金型の一方と他方とに選択的に充填可能な切替弁とを用い、第１の射出機による第１の金型に対する射出充填と、第２の射出機による第２と第３の両金型の一方の金型に対する射出充填とを略同時に開始し、前記一方の金型に対する保圧工程の完了直後に前記切替弁を切替えて第２の射出機により第２と第３の両金型の他方の金型に対する射出充填を開始し、又、本発明の第２の特徴によれば、３個の金型のうちキャビティ容積が最大の第１の金型に対して溶融樹脂の射出充填を行う第１の射出機と、第１の金型以外の第２と第３の２個の金型に対して溶融樹脂の射出充填を行う第２の射出機と、第２の射出機から射出される溶融樹脂を第２と第３の両金型に夫々供給する供給路を夫々開閉する開閉弁とを用い、第１の射出機による第１の金型に対する射出充填と、第２の射出機による第２と第３の両金型の一方の金型に対する射出充填とを略同時に開始し、第１の金型に対する射出充填工程完了以後であって前記一方の金型に対する保圧工程完了以前に、該一方の金型の前記開閉弁を開弁した状態で第２と第３の両金型の他方の金型の前記開閉弁を開弁して前記第２の射出機により前記他方の金型に対する射出充填を開始し、該他方の金型に対する保圧工程の途中で前記一方の金型の前記開閉弁を閉弁する。
【０００６】
型締め装置の型締め力は、第１の射出機から射出される溶融樹脂が充填される第１の金型に要する型締め力と、第２の射出機から射出される溶融樹脂が初めに充填される、第２と第３の両金型の一方の金型に要する型締め力との合計で足りて、発生すべき型締め力を軽減できる。
【０００７】
さらに、本発明の第１の特徴によれば、第２の射出機から射出される溶融樹脂が初めに充填される、第２と第３の両金型の一方の金型に対する保圧工程完了後の冷却工程の開始と同時に第２と第３の両金型の他方の金型に対する射出充填を開始するため、前記両金型による射出成形サイクルタイムが短縮でき、又、本発明の第２の特徴によれば、第２の射出機から射出される溶融樹脂が初めに充填される、第２と第３の両金型の一方の金型に対する保圧工程の途中で第２と第３の両金型の他方の金型に対する射出充填を開始するため、前記両金型による射出成形サイクルタイムがさらに短縮できる。
【０００８】
【発明の実施の形態】
図１及び図２は、単一の型締め装置１で型締めされる３個の金型２、３、４を備える射出成形装置の概要を示している。図１に示すように、型締め装置１は、固定盤１ａと、加圧源１ｂにより駆動される可動盤１ｃとを備え、固定盤１ａには３個の金型２、３、４の固定型２ａ、３ａ、４ａを取り付け、可動盤１ｃには３個の金型２、３、４の可動型２ｃ、３ｃ、４ｃを取り付けるように構成されている。また、図２に示すように、３個の金型中最大のキャビティ容積の第１金型２に第１射出機５が接続され、キャビティ容積の比較的小さな第２と第３の両金型３、４に第２射出機６が接続され、更に、第２と第３の金型３、４の各供給路には開閉弁７、８が夫々設けられている。
【０００９】
射出充填に際して、型締め装置１により第１乃至第３の全金型２、３、４を型締めし、また、第２金型３の開閉弁７を開弁すると共に第３金型４の開閉弁８を閉弁して第２射出機６から射出される溶融樹脂が初めに第２金型３に充填されるように調整する。この状態で、第１と第２の両射出機５、６から同時に溶融樹脂を射出して第１と第２の金型２、３の夫々に対し射出充填を行う。この際、型締め装置１の型締め力は第１と第２の金型２、３の夫々に要する型締め力の合計で足り、３個の金型に対し同時に溶融樹脂を射出充填する場合の型締め力（３個の金型の夫々に要する型締め力の合計）に比し軽減できる。射出充填工程が完了すると、保圧工程と冷却工程の順でこれらの工程から成る射出成形サイクルを夫々行う。尚、保圧工程では、第１と第２の両射出機５、６の射出圧力を比較的低圧にし、金型内の溶融樹脂を加圧下で凝固させ始め、一方、冷却工程では、非加圧下で金型内の樹脂を完全に凝固させる。
【００１０】
ところで、第２金型３の次には第３金型４に対して第２射出機６から溶融樹脂の射出充填を行い、射出成形サイクルを開始する。このようにして、第１乃至第３の金型２、３、４の夫々において、各工程段階で各金型に固有の工程時間に基づいた射出成形サイクルを行う。ここで、第２金型３に対する射出成形サイクル中の冷却工程が完了したタイミングで第２射出機６により第３金型４に対する射出充填を行って射出成形サイクルを開始すると、第２と第３の両金型３、４に対する射出成形サイクルの完了時間は、図３（ａ）にｔ₁として示される第１金型２に対する射出成形サイクルの完了時間を大幅に越える場合があり、第１乃至第３の全金型２、３、４が単一の型締め装置１で固定されていて第１乃至第３の金型２、３、４のいずれか１個に対してさえ、冷却工程の次に行う型開き工程に移行できないことと相俟って能率的でない。そこで、このような場合には、図３（ｂ）に示すように、第２金型３に対する射出成形サイクル中の保圧工程の完了時点Ｔ₁で、第２金型３の開閉弁７を閉弁すると共に第３金型４の開閉弁８を開弁し、第２射出機６から第３金型４に対して溶融樹脂の射出充填を行って第３金型４に対する射出成形サイクルを開始する。このようにして、第３金型４に対する射出充填工程後の射出成形サイクルと、第２金型３に対する冷却工程以降の射出成形サイクルとを並行して進行させて第２射出機６側の第２と第３の両金型３、４に対する射出成形サイクルが完了する時間をｔ₂に早める。尚、本実施の形態では、第２射出機６から射出される溶融樹脂を第２と第３の金型３、４の夫々に選択的に充填するように第２と第３の金型３、４の両開閉弁７、８を作動させ、かくて、両開閉弁７、８により、第２と第３の金型３、４の夫々に選択的に溶融樹脂を充填する切替弁を構成しているが、第２と第３の金型３、４の夫々に対して選択的に充填可能な三方弁のような単一の切替弁を用いることもできる。
【００１１】
図３（ｃ）は、第２と第３の両金型３、４に対する射出成形サイクルを更に早期に完了できる他の実施形態を示す。このものでは、第２金型３に対する射出成形サイクル中の保圧工程の途中の時点Ｔ₂で第２金型３の開閉弁７を開弁した状態で第３金型４の開閉弁８を開弁した後に、第２射出機６から第３金型４に対して溶融樹脂の射出充填を行って第３金型４に対する射出成形サイクルを開始し、この後、第２金型３に対する保圧工程の完了時点Ｔ₃で第２金型３の開閉弁７を閉弁すれば、第３金型４に対する射出充填工程後の射出成形サイクルと、第２金型３に対する保圧工程途中以降の射出成形サイクルとを並行して進行させることができて、第２射出機６側の第２と第３の両金型３、４に対する射出成形サイクルが完了する時間をｔ₃に更に早めることができる。この場合、保圧工程中の第２金型３は、第３金型４に対する射出充填工程以降の射出圧力の影響を受けるが、第２金型３の開閉弁７の閉弁以降はその影響を受けずに第２金型３に固有の冷却工程を確保できるので、第２金型３で成形される製品の品質に対して上記の第３金型４に対する射出圧力が及ぼす影響は限定的である。
【００１２】
【発明の効果】
以上の説明から明らかなように、本発明によれば、３個の金型に対し同時に溶融樹脂の射出充填を行う場合に比べ、型締め装置の型締め力が軽減でき、また、第２射出機６により溶融樹脂の射出充填を行う第２と第３の両金型３、４に対する射出成形サイクルタイムを短縮できる。そして、第１金型２に対する射出成形サイクルタイムに合せて第２と第３の両金型３、４に対する射出成形サイクルタイムを更に短縮することができる。
【図面の簡単な説明】
【図１】本発明方法の実施に用いる射出成形装置の概略平面図
【図２】図１の射出成形装置の要部の断面図
【図３】（ａ）第１金型に対する射出成形サイクルを示す図
（ｂ）第２、第３金型に対する射出成形サイクルを示す図
（ｃ）第２、第３金型に対する別の射出成形サイクルを示す図
【符号の説明】
１型締め装置
２第１金型３第２金型４第３金型
５第１射出機６第２射出機
７、８開閉弁[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an injection molding method using three molds clamped by a single mold clamping device.
[0002]
[Prior art]
Conventionally, as an injection molding method using three molds clamped by a single mold clamping device, molten resin is injected and filled into a first mold having the largest cavity volume among the three molds. Each mold using a first injection machine that performs injection and a second injection machine that performs injection filling of molten resin to the second and third molds other than the first mold On the other hand, it is known that the molten resin is injected and filled at the same time to shorten the time required for injection molding.
[0003]
[Problems to be solved by the invention]
The above injection molding method requires a powerful mold clamping device that can generate the mold clamping force as the sum of the mold clamping forces required for mold clamping during injection filling for each mold, and the size and shape of the molded product. In some cases, molding may become difficult, and when a new clamping device capable of generating a strong clamping force is procured, it becomes a factor of cost increase.
[0004]
In view of the above problems, the present invention can suppress the mold clamping force of the mold clamping device and efficiently perform injection molding using three molds clamped by a single mold clamping device. The challenge is to provide a method that can do this.
[0005]
[Means for Solving the Problems]
In order to solve the above problem, in an injection molding method using three molds clamped by a single mold clamping device, according to the first feature of the present invention, the cavity volume of the three molds A first injection machine for injecting and filling molten resin to the first mold having the largest size, and injection of molten resin to the second and third molds other than the first mold A second injection machine that performs filling, and a switching valve that can selectively fill one of the second and third molds with the molten resin injected from the second injection machine. The injection and filling of the first mold by the first injection machine and the injection and filling of one of the second and third molds by the second injection machine are started substantially simultaneously. Immediately after completion of the pressure-holding process for the nozzle, the switching valve is switched and the second injection machine fills the other mold of the second and third molds with injection. In addition, according to the second feature of the present invention, a first injection machine that performs injection filling of a molten resin to a first mold having the largest cavity volume among the three molds; A second injection machine that performs injection filling of the molten resin to the second and third molds other than the first mold, and a second injection of the molten resin injected from the second injection machine; Using an on-off valve that opens and closes a supply path that supplies each of the third molds, the first injection machine fills the first mold with injection, and the second and third injection machines perform the second and third injections. The injection filling of one mold of both molds is started almost simultaneously, and after the injection filling process for the first mold is completed and before the pressure holding process for the one mold is completed, the one mold With the on / off valve opened, the other on / off valve of the second and third molds is opened and the second injector Start the injection filling for square mold and closes the on-off valve of the one mold during the pressure holding process against said other mold.
[0006]
The mold clamping force of the mold clamping device is that the mold clamping force required for the first mold filled with the molten resin injected from the first injection machine and the molten resin injected from the second injection machine are the first. The sum of the clamping force required for one of the second and third molds to be filled is sufficient, and the clamping force to be generated can be reduced.
[0007]
Further, according to the first feature of the present invention, the pressure holding process for one of the second and third molds is first filled with the molten resin injected from the second injection machine. Simultaneously with the start of the subsequent cooling process, the injection filling of the second and third molds into the other mold is started, so that the injection molding cycle time by the both molds can be shortened, and the second of the present invention. According to the feature of the second and third in the middle of the pressure-holding step for one of the second and third molds, the molten resin injected from the second injection machine is initially filled. Since injection filling with respect to the other mold of both molds is started, the injection molding cycle time by both molds can be further shortened.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 show an outline of an injection molding apparatus including three molds 2, 3, and 4 that are clamped by a single mold clamping device 1. As shown in FIG. 1, the mold clamping device 1 includes a fixed platen 1a and a movable platen 1c driven by a pressure source 1b. The fixed platen 1a fixes three molds 2, 3, and 4. The molds 2a, 3a, and 4a are attached, and the movable platen 1c is configured to attach the movable molds 2c, 3c, and 4c of the three molds 2, 3, and 4. Further, as shown in FIG. 2, the first injection machine 5 is connected to the first mold 2 having the largest cavity volume among the three molds, and the second and third molds having a relatively small cavity volume. The second injection machine 6 is connected to 3 and 4, and on-off valves 7 and 8 are provided in the supply paths of the second and third molds 3 and 4, respectively.
[0009]
At the time of injection filling, the first to third all molds 2, 3, 4 are clamped by the mold clamping device 1, the on-off valve 7 of the second mold 3 is opened, and the third mold 4 is The on-off valve 8 is closed and adjusted so that the molten resin injected from the second injection machine 6 is first filled in the second mold 3. In this state, the molten resin is simultaneously injected from both the first and second injection machines 5 and 6 and injection filling is performed on each of the first and second molds 2 and 3. At this time, the mold clamping force of the mold clamping device 1 is the sum of the mold clamping forces required for the first and second molds 2 and 3, and the molten resin is injected and filled into the three molds simultaneously. The mold clamping force (total of the mold clamping forces required for each of the three molds) can be reduced. When the injection filling process is completed, an injection molding cycle including these processes is performed in the order of the pressure holding process and the cooling process. In the pressure-holding process, the injection pressures of both the first and second injection machines 5 and 6 are set to be relatively low, and the molten resin in the mold starts to solidify under pressure. The resin in the mold is completely solidified under pressure.
[0010]
By the way, next to the second mold 3, the third mold 4 is injected and filled with molten resin from the second injection machine 6, and an injection molding cycle is started. In this way, in each of the first to third molds 2, 3, and 4, an injection molding cycle based on the process time unique to each mold is performed in each process step. Here, when the injection molding cycle is started by performing the injection filling with respect to the third mold 4 by the second injection machine 6 at the timing when the cooling process in the injection molding cycle for the second mold 3 is completed, the second and third The completion time of the injection molding cycle for both molds 3 and 4 may greatly exceed the completion time of the injection molding cycle for the first mold 2 shown as t _{1 in} FIG. The third all molds 2, 3, 4 are fixed by a single mold clamping device 1, and even for any one of the first to third molds 2, 3, 4, Combined with the inability to move to the next mold opening process, it is not efficient. Therefore, in such a case, as shown in FIG. 3B, the opening / closing valve 7 of the second mold 3 is turned on at the time T ₁ when the pressure holding step in the injection molding cycle for the second mold 3 is completed. The valve is closed and the opening / closing valve 8 of the third mold 4 is opened, and the injection molding cycle for the third mold 4 is performed by performing injection filling of the molten resin from the second injection machine 6 to the third mold 4. Start. In this way, the injection molding cycle after the injection filling process for the third mold 4 and the injection molding cycle after the cooling process for the second mold 3 are advanced in parallel, so that the second injection machine 6 side first. hasten 2 and the time of injection molding cycle is completed for the third molds 3 and 4 to t _2. In the present embodiment, the second and third molds 3 are selectively filled into the second and third molds 3 and 4 with the molten resin injected from the second injection machine 6. Thus, the switching valve for selectively filling the molten resin into the second and third molds 3 and 4 is constituted by the both opening and closing valves 7 and 8. However, it is also possible to use a single switching valve such as a three-way valve that can be selectively filled in each of the second and third molds 3 and 4.
[0011]
FIG. 3C shows another embodiment in which the injection molding cycle for both the second and third molds 3 and 4 can be completed even earlier. In this case, the on-off valve 8 of the third mold 4 is opened in a state where the on-off valve 7 of the second mold 3 is opened at the time T ₂ in the middle of the pressure-holding process in the injection molding cycle for the second mold 3. After opening the valve, the second injection machine 6 performs the injection filling of the molten resin to the third mold 4 to start the injection molding cycle for the third mold 4. If the on-off valve 7 of the second mold 3 is closed at the time T ₃ when the pressurizing process is completed, the injection molding cycle after the injection filling process for the third mold 4 and the middle of the pressure-holding process for the second mold 3 are performed. The injection molding cycle can be advanced in parallel, and the time for completing the injection molding cycle for the second and third molds 3 and 4 on the second injection machine 6 side is further advanced to t _3. Can do. In this case, the second mold 3 in the pressure holding process is affected by the injection pressure after the injection filling process on the third mold 4, but the influence after the valve closing of the on-off valve 7 of the second mold 3 is affected. Since the cooling process specific to the second mold 3 can be secured without receiving, the influence of the injection pressure on the third mold 4 on the quality of the product molded by the second mold 3 is limited. It is.
[0012]
【The invention's effect】
As is apparent from the above description, according to the present invention, the mold clamping force of the mold clamping device can be reduced as compared with the case where the molten resin is simultaneously injected and filled into the three molds, and the second injection. The injection molding cycle time for the second and third molds 3 and 4 in which the molten resin is injected and filled by the machine 6 can be shortened. Then, the injection molding cycle time for the second and third molds 3 and 4 can be further shortened in accordance with the injection molding cycle time for the first mold 2.
[Brief description of the drawings]
FIG. 1 is a schematic plan view of an injection molding apparatus used for carrying out the method of the present invention. FIG. 2 is a cross-sectional view of the main part of the injection molding apparatus in FIG. 1. FIG. 3 (a) shows an injection molding cycle for a first mold. (B) Diagram showing the injection molding cycle for the second and third molds (c) Diagram showing another injection molding cycle for the second and third molds
DESCRIPTION OF SYMBOLS 1 Clamping apparatus 2 1st metal mold | die 3 2nd metal mold | die 4 3rd metal mold | die 5 1st injection machine 6 2nd injection machine 7, 8 On-off valve

Claims

In an injection molding method using three molds clamped by a single mold clamping device, injection filling of molten resin is performed on a first mold having the largest cavity volume among the three molds. A first injection machine to be performed, a second injection machine for injecting and filling molten resin into the second and third molds other than the first mold, and the second injection machine. Using a switching valve capable of selectively filling one and the other of the second and third molds with the molten resin to be injected, injection filling the first mold with the first injection machine; The injection filling of one of the second and third molds by the second injection machine is started substantially simultaneously, and the switching valve is switched immediately after completion of the pressure-holding process for the one mold. Injection molding characterized by starting injection and filling of the second and third molds into the other mold by the second injection machine Law.

In an injection molding method using three molds clamped by a single mold clamping device, injection filling of molten resin is performed on a first mold having the largest cavity volume among the three molds. A first injection machine to be performed, a second injection machine for injecting and filling molten resin into the second and third molds other than the first mold, and the second injection machine. Using an on-off valve that opens and closes supply paths for supplying the molten resin to be injected to both the second and third molds, respectively, and injection filling the first mold with the first injection machine; The injection filling of one of the second and third molds by the second injection machine is started substantially at the same time, and after the completion of the injection filling process for the first mold, the one mold is maintained. Prior to the completion of the pressurizing step, the other mold of the second and third molds with the on-off valve of the one mold opened. The valve is opened and injection filling of the other mold is started by the second injection machine, and the open / close valve of the one mold is closed during the pressure holding process for the other mold. An injection molding method characterized by: