JP2007125708A - Injection mold and injection molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection mold capable of well separating a molded product and a sprue runner by a simple constitution at the time of separation of the sprue runner from the molded product and capable of manufacturing the molded product without requiring the post-finish of a gate. <P>SOLUTION: The injection mold is constituted so that the gate is automatically cut at the time of mold release of the molding after injection molding and the molding and the runner are cut within a mold by a time differential cutting system. This injection mold is equipped with the runner holding part connected to a runner push-out plate capable of freely separating the runner after mold release and the mold for molding. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a structure of an injection mold for runner or gate cutting in a mold.

  A schematic diagram of an injection mold immediately before the molded product and the spool runner are cut at the gate position by the product extrusion plate in the conventional molding die is shown in FIG. 6, and the product extrusion plate in the conventional molding die is shown in FIG. FIG. 7 shows a schematic diagram of an injection mold immediately after the molded product and the spool runner are cut at the gate position.

Conventionally, after releasing a molded product after injection molding, the molded product and the runner are connected with the molded product and the runner, and the product and the gate are cut manually with a nipper or the like and molded outside the mold. Goods and runners were separated. However, not only is labor cost increased, but man-hours are increased and productivity is poor, and by cutting the gate outside the mold, the molded product drops in temperature and removes the soft runner. I was coming.
JP-A-6-143351

  Therefore, as disclosed in JP-A-6-143351, a molded article is formed after injection molding so that the gate cut of the runner can be automatically performed in the mold by attaching to a dedicated separating apparatus (gate 5 cutting apparatus) and separating and cutting. The runner is separated from the runner, and the runner is provided with an undercut portion so that the gate is separated and cut by extruding the spool runner by the product extruding plate 4 when releasing the molded product after injection molding. This method reduces man-hours by not relying on manpower, and by cutting the gate in the mold, the soft runner can be removed while the temperature of the molded product does not drop, so it can be molded well without reducing cutting accuracy. The product and runner can be separated. However, in such a method of pushing out the spool runner by the product extrusion plate 4, the mold starts to open and is pushed out by the product extrusion plate 4. Although it was prevented, the remaining gate could not be avoided completely. Specifically, for example, in a manufacturing die for a winding bobbin of an ignition coil, first, the die starts to open and the product extrusion plate 4 is pushed out to the spool runner 3, and the molded product 1 and the spool runner 3 are cut at the position of the gate 5. Then, the molded product 1 was discharged from the mold. As a result, a perfect molded product can be molded by undercutting, but the cost increased and the size of the equipment was increased. Further, in the above prior art, by cutting the gate, the spool runner 3 is inclined, and the product may not be taken out successfully. In addition, it is desirable to perform gate cutting in a soft state immediately after injection. In this technology, the mold is opened after the resin has cooled and solidified, so when the gate is separated, the cut product and the gate part are cold. Can not do quickly and well. Therefore, in view of the above problems, the present invention can easily separate a molded product and a spool runner with a simple structure when separating a runner from a product, and can produce a product without requiring a gate finishing. An object is to provide a mold for molding.

  In order to solve the above problems, the present invention has the following configuration. That is, according to the first aspect, in the injection mold, the gate is automatically cut when the molded product after injection molding is released, and the molded product and the runner are separated in the mold by the time difference cutting method. An injection mold having a runner holding portion connected to a runner extrusion plate that can freely disengage the runner later and a mold for molding a molded product. According to a second aspect of the present invention, in the injection mold according to the first aspect, the runner holding portion holds the runner by a knock pin. According to a third aspect of the present invention, the runner holding portion includes a knock pin for holding the runner and a spring elastic material having a spring elastic force connected to the knock pin, and the spring elastic material is semi-fixed to the runner extrusion plate. 3. An injection mold according to claim 2, further comprising a spring elastic mechanism. According to claim 4, in the mold for injection molding, the runner holding portion holds the runner, and the gate is automatically timed and cut at the initial stage of the extrusion of the molded product at the time of releasing the molded product after injection molding. The injection molding method is characterized in that the runner is detached from the runner holding portion. According to a fifth aspect of the present invention, there is provided the injection mold according to any one of the first to fourth aspects, wherein the gate has a tapered gate and a slope from the root.

  By adopting the configuration of the present invention, the molded product is automatically and smoothly cut in the mold when the mold is released. Accordingly, a cutting machine for gate cutting and a manpower are not required, and the molded product and the runner can be well separated with a simple configuration. Therefore, productivity can be improved and production can be performed at low cost.

  The present invention will be described according to the following embodiments. FIG. 1 is a schematic view of an injection mold immediately before the molded product and the spool runner cut at the gate position, representing Example 1 of the present invention. FIG. 2 is a schematic view of an injection mold immediately after the molded product representing the first embodiment of the present invention and the spool runner are cut at the position of the gate. FIG. 3 is a schematic view of an injection mold immediately before the molded product representing the second embodiment of the present invention and the spool runner cut at the gate position. FIG. 4 is a schematic view of an injection mold immediately after the molded product representing the second embodiment of the present invention and the spool runner are cut at the position of the gate. FIG. 5 is a schematic view of the gate portion of the present invention.

  The gate cut method of the runner as an embodiment of the present invention is a time difference cut method in which the molded product and the spool runner are separated after the release of the molded product after injection molding. A knock pin 6 is inserted as a runner holding portion connected to the extrusion plate so that the molded product 1 and the spool runner 3 do not stick together when the molded product 1 after injection molding is released. This mechanism is performed in the mold. When the molded product 1 after the injection molding is released, the molded product 1 is first pushed out from the lower part and released. At that time, the runner gate 5 fixed to the knock pin 6 is automatically separated from the molded product 1 and then spooled. The knock pin 6 of the runner 3 is disengaged from the spool runner 3.

  The time difference mechanism for automatically time difference cutting the gate at the initial stage of the extrusion of the molded product at the time of releasing the molded product after the injection molding as described above is specifically shown in FIGS. Furthermore, between the knock pin 6 and the runner extrusion plate 7, when the gate 5 of the spool runner 3 and the molded product 1 are moved in different directions when the molded product 1 is released, the gate 5 and the molded product 1 are completely connected. A spring elastic mechanism is provided which is semi-fixed with a spring elastic material (not shown) having a spring elastic force larger than the spring elastic force corresponding to the moving distance to be cut and connected to the knock pin. Thus, the spool runner 3 fixed to the knock pin 6 is semi-fixed by the spring elastic force with the runner push-out plate 7.

  At the time of releasing the molded product 1 after the injection molding, the molded product 1 is first pushed upward by the lower runner extrusion plate 7, and the molded product 1 is released from the mold accordingly. The distance between the semi-fixed gate 5 of the spool runner 3 and the molded product 1 gradually increases as the molded product 1 is released. When the spring force of the spring elastic material increases at a certain distance and becomes greater than the tension between the gate 5 and the molded product 1, the gate 5 and the molded product 1 are completely cut. In this way, the gate 5 is automatically separated from the molded product 1 with a time difference, and then the knock pin 6 of the spool runner 3 is disengaged from the spool runner 3. After that, the runner is released. Moreover, the time difference at which the gate 5 is separated from the molded product 1 can be set by adjusting the spring elastic force of the previous spring elastic material. Therefore, by adopting the spring elastic mechanism, the gate cut is not necessary, and the gate can be separated before the mold before the resin is cooled and solidified is opened, so that the gate can be cut quickly. In addition, since the time difference mechanism can be configured with a simple configuration, the molded product is automatically and smoothly cut at the time of mold release, and the molded product and runner can be satisfactorily maintained without damaging the appearance and performance of the molded product. Can be separated.

  Further, as another embodiment, the gate cut method of the runner is as follows. In the second embodiment as shown in FIG. 3 to FIG. 4, when the molded product 1 after the injection molding is released, the molded product 1 is first cut by the lower knock pin 6. The spool runner 3 is pushed upward, and accordingly, the gate 5 is automatically separated from the molded product 1 and released from the mold. This mechanism is performed in the mold. At a certain distance, the plate 7 is then lifted, and the molded product 1 is completely released from the mold. Thus, the gate 5 and the molded product 1 are automatically separated with a time difference, and then the knock pin 6 of the spool runner 3 is disengaged from the spool runner 3, and the spool runner 3 is discharged. Therefore, by adopting the present embodiment, it is not necessary to manually perform the gate cut, and the gate can be separated before the mold before the resin is cooled and solidified is opened, so that the gate can be cut quickly. In addition, since the time difference mechanism can be configured with a simple configuration, the molded product is automatically and smoothly cut at the time of mold release, and the molded product and runner can be satisfactorily performed without damaging the appearance and performance of the molded product. Can be separated.

  The inventor has also found a structure in which gate cutting can be performed more easily, the gate remaining is minimized, and post-finishing is unnecessary. More specifically, the gate 5 as shown in FIG. 5 is tapered from the runner base and has a slope 5a. By adopting this structure in the first and second embodiments, the gate 5 is easily and automatically separated from the molded product 1 and released from the mold. Therefore, the remaining gate is minimized, and post finishing is not required even if the gate is cut.

  With the above configuration, the molded product and the runner can be separated satisfactorily. Cutting of molded products and runners does not require any special configuration, and products can be produced satisfactorily. Needless to say, by adopting the above-described configuration, the conditions for molding a molded product can be widely adjusted without affecting the conditions for molding the molded product. Therefore, a versatile injection mold and injection molding method can be provided. Further, the above-described configuration has been described for the embodiment of the injection mold and the injection molding method of the present invention. However, the embodiment is not particularly limited to the above embodiment. Various modifications and improvements that can be made by those skilled in the art are also possible.

It is a schematic diagram of the metal mold | die for injection molding just before a molded article and spool runner showing Example 1 of this invention cut | disconnect at the position of a gate. It is a schematic diagram of the injection mold immediately after the molded product and the spool runner representing Example 1 of the present invention cut at the position of the gate. It is a schematic diagram of the injection mold immediately before the molded product and the spool runner representing Example 2 of the present invention cut at the position of the gate. It is a schematic diagram of the injection mold immediately after the molded product and the spool runner representing Example 2 of the present invention cut at the position of the gate. It is a schematic diagram of the gate part of this invention. It is a schematic diagram of an injection mold immediately before a molded product and a spool runner are cut at a gate position by a product extrusion plate in a conventional mold. It is a schematic diagram of an injection mold immediately after a molded product and a spool runner are cut at a gate position by a product extrusion plate in a conventional mold.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Molded product 1a Terminal part insertion part 2 Core 3 Spool runner 4 Product extrusion plate 5 Gate 6 Knock pin 7 Runner extrusion plate

Claims (5)

  In the mold for injection molding, the gate is automatically cut when the molded product after injection molding is released, and the runner can be freely dissociated after mold release by separating the molded product from the runner in the mold by the time difference cutting method. An injection mold comprising a runner holding portion connected to a runner extrusion plate and a mold for molding a molded product.   The injection mold according to claim 1, wherein the runner holding part holds the runner with a knock pin.   The runner holding part is composed of a knock pin for holding the runner and a spring elastic material having a spring elastic force connected to the knock pin, and the spring elastic material has a spring elastic mechanism semi-fixed to the runner extrusion plate. The injection mold according to claim 2, wherein the injection mold is provided.   In the mold for injection molding, the runner holding part holds the runner, and the gate is automatically timed at the beginning of extrusion of the molded product when the molded product is released after injection molding, and then the runner holds the runner. An injection molding method characterized by detaching from the part.   5. The injection mold according to claim 1, wherein the gate has a tapered gate and a slope from the root.

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