JPH0516263U - Injection mold - Google Patents

Abstract

(57) [Summary] [Purpose] A mold that can reduce the occurrence of uneven thickness in injection molding of thin and long cylindrical containers, simplify mold manufacturing and maintenance work, and facilitate accuracy. Providing structure. A mold for injecting a molten resin into a cavity 5 formed between a female mold 6 and a core 8 to mold an elongated cylindrical container having one end open, the female mold 6 and a core body 81. An injection molding die in which a core-8 composed of a slide core 82 and a slide core 82 are both incorporated into the die in a nested structure, and the female die 6 and the slide core-82 have a seal wax fitting structure.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an injection molding die capable of molding a thin and long cylindrical container without uneven thickness.

[0002]

[Prior Art]

 2. Description of the Related Art Conventionally, for example, an injection mold as shown in FIG. 2 has been used as a mold for injection-molding an elongated thin-walled cylindrical plastic molded product such as a tester, a urine collecting tube, and a blood collecting tube. In this mold, the female die 6 is incorporated in the fixed-side template 4 in a nested structure, and the core 8 is also incorporated in the stripper plate 7 and the movable-side template 9 in a nested structure. In addition, 1 is a fixed side mounting plate, 61 is a cooling hole, and 10 is a moving side mounting plate.

When the mold is clamped, a cavity 5 is formed between the female mold 6 and the core 8 and the stripper plate 7, and a cavity 5 is formed in the cavity 5 from an injection cylinder (not shown) to the sprue 2 and the gate 3. Molten resin is injected through it to obtain an elongated thin-walled cylindrical container.

In order to mold such a molded product without uneven thickness, it is necessary to form the cavity 5 in the female mold 6 by incorporating the core 8 without eccentricity. For that purpose, first, it is necessary that the core 8, the stripper plate 7 and the moving side template 9 are fitted precisely as designed, especially the core 8 and the moving side template 9.

However, even if the core 8, the stripper plate 7 and the moving side mold plate 9 are precisely fitted and held, when the fixed side mold plate 4, the stripper plate 7 and the moving side mold plate 9 are fitted together during mold clamping. In addition, if the flatness and parallelism of the mating surfaces of these mold plates are not good, these mold plates will be displaced from the predetermined positions, and as a result, the axial centers of the core 8 and the female mold 6 will be displaced. Invite. Further, the mating surface of the fixed-side mold plate 4, the stripper plate 7, and the movable-side mold plate 9 is a portion that collides with each molding cycle. Therefore, even if it is initially accurate, it gradually wears or dents. Is. As a result, the female die 6 and the core 8 are eccentric. In particular, in the case of taking a large number of pieces, the method of eccentricity becomes different, and it is necessary to correct all the contact surfaces of the mold plates and the fitting of the core 8 and the moving side mold plate 9. Therefore, it takes a great deal of effort to perform all of these eccentricity corrections.

[0006]

[Problems to be solved by the device]

 As described above, in such a product, in order to reduce the uneven thickness, firstly, the core needs to be fitted precisely to the moving-side mold as designed. .. Secondly, the flatness and parallelism of the contact surface between the fixed-side template and the stripper plate and the movable-side template must be good. In order to reduce the uneven thickness in this way, there are problems that two operations are required, which is complicated, time consuming, and difficult to achieve accuracy. Furthermore, the above-mentioned mating surface wears as the number of moldings increases, and it causes dents and leads to eccentricity of the core, which is a difficult work to correct, but especially in the case of multi-cavity production, much labor is required. I need. Therefore, there has been a demand for the appearance of a mold structure that simplifies the manufacture of molds for such products, facilitates accuracy, and facilitates maintenance work such as modification of molds.

[0007]

[Means for Solving the Problems]

 As a result of various studies on the above points, the inventor of the present invention injects molten resin into a cavity formed between a female mold, which is a stationary mold, and a core, which is a movable mold, and one end of the molten resin is injected. A mold for molding an elongated cylindrical container having an opening, wherein the female mold and the core are incorporated in the mold in a nested structure, respectively, and the female mold and the core are fitted with a seal wax or a concavo-convex fit. It was found that the above problem can be solved by using an injection molding die characterized by

[0008]

[Action]

 Since the female mold and the core of the core are fitted by the seal wax fitting or the concave fitting of the female mold and the core, there may be a gap in the mating surface of the fixed mold plate and the moving mold plate. Also, the smoothness and parallelism of the mating surfaces of these templates do not pose a problem.

As a result, the manufacturing of the mold is simplified, and the accuracy can be easily obtained. In particular, in the case of taking a large number of pieces, it is possible to perform the centering of a specific female die and the core independently and separately. In addition, even if the mating of a specific female mold and core deteriorates due to wear due to long-term operation, the problem will be limited to that specific female mold and core, and there will be no effect on others. Therefore, if the above-mentioned female mold with poor fitting is replaced with the core, the operation can be continued. This replacement can be easily done because the female mold and core have a nested structure.

[0010]

【Example】

 FIG. 1 shows an example of a multi-cavity injection molding die according to the present invention, and is a sectional view showing a portion related to one cavity.

1 is a fixed side mounting plate, 2 is a sprue, 3 is a gate, 4 is a fixed side mold plate, 6 is a female mold, 7 is a stripper plate, 8 is a core, 9 is a moving side mold plate, and 10 is a moving side. It is a mounting plate, and the female die 6 and the core 8 have a nested structure. Then, at the time of closing as shown, the cavity 5 surrounded by the female die 6 and the core 8 is formed.

The core 8 is composed of a core body 81 and a slide core 82 slidably fitted to the core body 81, and a mating portion between the female die 6 and the slide core 82 is a seal wax fitting. Although not shown, the stripper plate 7 and the slide core 82 are fixed by screws or the like.

Although not shown, the female die 6 and the core body 81 are provided with cooling holes as needed. Molten resin injected from an injection cylinder (not shown) passes through the sprue 2 and the gate 3 and is filled in the cavity 5. At this time, this centering is determined only by the seal wax fitting between the female die 6 and the sliding core 81, and is not related to the parallelism or smoothness of the mating surfaces of the fixed side mold plate 4 and the moving side mold plate 9. Become. Therefore, even if the mating surface has irregularities, eccentricity between the female die 6 and the core body 81 does not occur. Although FIG. 1 shows only one combination of the female die 6 and the core 8, it is possible to perform the centering independently for each combination of the female die and the core. In the mold of the present invention, the female mold 6 and the core 8 are first incorporated in the stationary mold plate 4 and the moving mold plate 9 in a nested structure. In this way, the mold production was greatly simplified and made possible with high accuracy.

Next, when operating for a long time, the fitting portion between the female die and the core may be worn or dented. Even in such a case, if the above-mentioned mold structure is adopted, the problem can be limited to the combination of the specific female mold and core that have been worn, and the eccentricity due to the influence of other female mold and core. Does not occur. Therefore, it is possible to return to normal operation by replacing only the specific female mold that has worn out with the core. The above replacement can be easily performed because it is fitted with a female-type and core-type nested structure. The product is taken out by sliding the stripper plate 7 and the slide core 82 with respect to the core body 81 when the mold is opened.

FIG. 2 shows another embodiment of the present invention, which has the same structure as the injection molding die shown in FIG. 1 except that the slide core 82a has an uneven fitting structure with respect to the female die 6a. It is said that.

[0016]

[Effect of the device]

 By adopting the mold structure of the present invention, it becomes possible to perform centering between the female mold and the core simply and accurately. In addition, the core that has been set once will not shake even when tightened during mold clamping, and will not be distorted by damage to other female mold and core mating parts. This is due to the structural feature of the mold of the present invention in which the centering of each female die and the core is determined only by the fitting of each female die and the core.

By using the mold having such a structure, the uneven thickness of the product is significantly reduced. As a result, physical properties of the product such as strength and gas barrier property are improved. In addition, the fact that the average thickness of products has been reduced as a result of the reduction in uneven product thickness is another effect that cannot be overlooked, which leads to lower product costs.

[Brief description of drawings]

FIG. 1 is a partial sectional view of an embodiment of an injection mold of the present invention.

FIG. 2 is a partial cross-sectional view of another embodiment of the injection mold of the present invention.

FIG. 3 is a cross-sectional view of an injection mold conventionally used for molding an elongated cylindrical container.

[Explanation of symbols]

 1 fixed side mounting plate 2 sprue 3 gate 4 fixed side template 5 cavity 6, 6a female 7 stripper plate 8 core 81 core body 82, 82a slide core 9 moving side template 10 moving side mounting plate

Claims (1)

[Scope of utility model registration request] 1. A mold for injecting molten resin into a cavity formed between a stationary mold and a moving mold core to form a long and narrow cylindrical container having one end opened. And an injection molding die characterized in that the female die and the core are respectively incorporated in the die in a nested structure, and the female die and the core are engaged with each other by a seal wax or an uneven fit. .