JPS63153111A - Molding apparatus for resin product - Google Patents

Abstract

PURPOSE:To mold both a molding composed of a single material and a molding of a sandwich structure at the same time by using a single mold, by making the poured distributed amt. of the first resin material smaller in the second cavity side from a bypass path than in the first cavity side. CONSTITUTION:The relation between the cross-sectional area S1 of the first sprue 4a and the cross-sectional area Sb of a bypass runner 4c is set to be S1>Sb. When the first cavity 5a is filled with the first resin material A, the first resin material A is then poured into the second cavity 5b through a bypass runner 4c. Followed by the filling operation with the first resin material A, the second resin material B is poured into the mold through the second cylinder 2. As cooling and solidifying of the part of the first resin material A contacting the inner faces of the sprue, the runner and the cavity proceeds and the inner part is still in a molten state, when the second resin material B is sufficiently poured into the second cavity 5b, a sandwich molding is obtained in the second cavity 5b.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention relates to a molding apparatus for resin products, and in particular, it is capable of successively injecting two types of materials into the cavity of one mold, thereby molding a molded product with a multilayer structure or a laminated structure. The present invention relates to a method for simultaneously manufacturing a molded product having a single-layer structure and a single-layer structure using a single mold.

(Background of the invention) Many plastic products used for precision parts and parts for automobiles or leisure products are manufactured by plastic injection molding, which generally involves molding one or more molded products. Plastic material is injected from one injection cylinder into a mold having a cavity for molding (hereinafter referred to as the general method for convenience).

In addition, for certain molded products, such as operation buttons for so-called office automation equipment such as word processors and calculators, two-color molding is usually used, which involves two injection cylinders for injecting two different materials. It is molded by a method called.

Furthermore, such as the housing for the above-mentioned OA equipment, etc.
For parts where it is desired to give different functions and properties to the surface and core, a method is adopted in which each part (surface and core) is molded using different materials, and this is usually different from the two-color molding method mentioned above. It is distinguished and called the sandwich molding method.

These general methods, two-color molding method, and sandwich molding method each have their advantages and disadvantages, and in the past, each has been adopted depending on the purpose, but it has been difficult to use them simultaneously, so they have not been adopted.

For example, if you try to simultaneously manufacture a molded product with a single layer structure made of a single material and a sandwich molded product with a laminated structure made of two materials using a car mold. , the sandwich molding method was published in Japanese Patent Publication No. 1973-
As is known from Japanese Patent Publication No. 26108 and Japanese Patent Publication No. 60-59129, the resin material is injected into the cavity in the mold from the same sprue, so the resin material that is injected first and the resin material that is injected later are It is not possible to distinguish the injection path of the resin material to be injected, and as a result, it is not possible to simultaneously manufacture single-layered molded products made of only a single material.

Also, considering that manufacturing a single-layer molded product made of a single material and a two-color molded product made of two materials are performed at the same time, in this case, two-color molded products are produced. Since two injection cylinders are used for this purpose, it is possible to manufacture both molded products with a single mold. However, it is not practical to manufacture such a monolayer structure molded product made of a single material and a two-color molded product using a single mold, and this cannot be called a simultaneous molding method in the first place. That is, the two-color molding method in this case involves injecting the first resin material into the cavity of the mold, cooling and solidifying the injected first resin material, and then inverting the mold or partially expanding the cavity. The second resin material is then injected into the cavity, and in practice, a single-material molded product and a dual-material molded product are not molded at the same time, requiring twice as many molding cycles. This is because Note that depending on the two-color molding method, it is impossible to produce a molded product in which the core material is covered with a surface layer like the sandwich structure described above, and it is not possible to produce a molded product with the sandwich structure described above and a molded product made of a single material at the same time. cannot be manufactured.

(Objective of the Invention) The present invention has been made from the above-mentioned viewpoints, and its object is to produce a molded product made of a single material and a sand-inch structure using a single mold and a single molding cycle. An object of the present invention is to provide a molding device for resin products that is capable of molding a molded product at the same time.

(Summary of the Invention) Therefore, the feature of the resin product molding apparatus of the present invention, which has been made to achieve the above object, is that it provides a void space for molding a molded product made of the first resin material. At least one first cavity and at least one second cavity providing a cavity for molding a layered molded article made of the first resin material and the second resin material are provided inside. For the molding mold 2 above, the first
A resin product molding apparatus comprising: a first injection device for injecting a second resin material into the mold; a second injection device for injecting a second resin material into the mold; The layer mold includes a first path provided to guide the injected first resin material from the first injection device to the first cavity, and a first path branched from the middle of the first path. a bypass path provided to guide the resin material into the second cavity, and a second path provided to guide the injected second resin material from the second injection device to the second cavity, The second path is connected to the second cavity through the bypass path by being connected to the bypass path halfway, and the second path is connected to the second cavity through the bypass path, and the second path is connected to the second cavity through the bypass path. When injecting, the injection amount into the first cavity via the first path and the injection amount into the second cavity via the bypass path are smaller on the latter bypass path side in relation to the volume of each cavity. The structure is such that the amount of injected resin is relatively small compared to the volume.

In the above configuration, the injection amount relative to the volume of each cavity is set to be small on the latter bypass route side (the amount of injected resin is relatively small compared to the volume inside the cavity), for example, on the first cavity side and the second cavity side. If the volumes including the volumes are approximately the same, the flow resistance of the first resin material to the second cavity side is greater than the flow resistance of the first resin material to the first cavity side. As a result, on the second cavity side, the injection amount of the first resin material relative to the cavity volume is relatively slower (lower) than on the first cavity side.

Specifically, it can be configured by providing a distribution control means that distributes the injection amount between a first path that leads the first resin material to the first cavity and a bypass path that leads the first resin material to the second cavity. In other words, the distribution control means that distributes the injection amount so that the injection amount is small in the former (first path side) and small in the latter (bypass path side) is, for example, based on the average path cross-sectional area S1 of the first path. and the internal cross-sectional area s of the bypass route
b can be set so that 31>Sb, so that the difference in flow resistance of the first resin material is imparted to the structure of the mold. In addition, independent heating means are installed at predetermined positions corresponding to each of the above-mentioned paths of the mold, and the temperature of the mold (mold temperature on the first path side) is controlled by a heating control device connected to these heating means. )> (mold temperature on the bypass path side), and the first
A structure in which the viscosity changes due to cooling of the resin material is preferably adopted.

In addition, the amount of injection into the first cavity via the first path and the amount of injection into the second cavity via the bypass path,
Distribution control, which sets the relationship between each cavity and the injection volume so that the latter bypass path side is small (the amount of resin injected is relatively small compared to the volume inside the cavity), is the same as the above-mentioned method that makes a difference in the injection volume. In addition, it is also possible to implement a method that provides a difference in the volume of the cavity to be injected. In this case, the configuration is provided by setting the cavity volume so that the latter becomes a dog, contrary to the method of giving a difference in the injection amount. Specifically, for example, if (first route volume + first cavity volume)≦(second cavity volume in bypass route volume), then the first resin material is distributed to the first cavity and the second cavity. Even if the injection amounts are approximately equal, when the injection into the first cavity is completed, the injection into the second cavity is not yet completed, and substantially the same as the above-mentioned method of giving a difference in flow resistance, the first resin material It is possible to inject the second resin material into the second cavity after the injection of the second resin material.

(Example of the invention) The present invention will be described below based on embodiments shown in the drawings.

Drawings 1 to 5 are for explaining an outline of the configuration of a molding device according to the present invention - an example, and a molding state when the device is used, and FIGS. 6 to 9 show a mold. Fig. 10 to Fig. 12 are diagrams showing the flow state of the first and second resin materials injected into the interior, and Figs. This is what is shown.

In FIG. 1, 1 indicates a first cylinder for plasticizing and injecting a first resin material A, and 2 indicates a second cylinder for plasticizing and injecting a second resin material B. It shows.

3.4.5 constitutes a molding mold that forms the main body of the molding device together with the injection cylinder, and in this example, inside this molding mold there are a sprue, a first path consisting of a runner, and a first path. Two paths are formed substantially parallel to each other, and a bypass path is formed to connect the first path and the second path.

Three of the molding molds are fixed plates, and a first sprue 38 connected to the first cylinder 1 at the injection port 1a is spaced apart from the first sprue 38 by a predetermined distance. , and a second sprue 3b connected to the second cylinder 2 through an injection port ib.

4 indicates a runner plate, in which a first runner 4a contacts the fixed plate 3 at the plane XX and communicates with the first sprue 38; a second runner 4b communicates with the second sprue 3b; A pair of first. It has a bypass runner 4C that connects the second runners 4a and 4b.

The above first sprue 3a and first runner 4a constitute a first path, and similarly the second sprue 3b and second runner 4b
constitutes a second path, and the bypass runner 4c constitutes a bypass path.

5 is a template, and the above-mentioned runner plate 4 is attached on the Y-Y1 plane.
The first gate 4g1, which is the end of the first runner 4a, faces the first cavity 4i5a for molding the first molded product, and the second gate 4g1, which is the end of the second runner 4b, faces the first gate 4g1. It has a second cavity 5b facing two gates 4gz and for molding a second molded product.

The first cavity 5a and the second cavity 5b in this example form cavities formed for molding different molded products.

Next, a case in which a resin molded product is molded using the molding apparatus having the above configuration will be explained with reference to FIGS. 2 to 9.

First, the first resin material A is injected from the first cylinder 1 into the mold shown in FIG.

The injected first resin material A passes through the first sprue 3a, the first runner 4a, and then the first gate 4g1 and is injected into the first cavity 5a. At this time again,
A portion of the first resin material A from the first sprue 38 is ready to be injected into the second cavity 5b from the bypass runner 4C through the second runner 4b (see FIG. 1). In this example, as shown in FIG. 4, the cross-sectional area S1 of the first sprue 48 and the bypass runner 4 are
Since the relationship of the cross-sectional area sb of C is set as Si > Sb, the flow path resistance is smaller in the former first sprue 4a.
As a result, the first injected water is injected into the first container 5a (see FIG. 2).

When the injection of the first resin material A into the first cavity 5a progresses and the inside of the first cavity 5a is filled with the first resin material A (see FIG. 2), next, the first resin material A is filled with the first resin material A. The resin material A is injected into the second cavity 5b via the bypass runner 4c (see Fig. 3),
When this reaches a predetermined amount, the injection operation of the first resin material A is completed.

The injection amount of the first resin material A injected into the second cavity 5b at this time is the total internal volume of these cavities, the second
By predetermining conditions such as the layer thickness of the surface of the sandwich molded product that forms acid in the cavity, the second
The injection and filling of the first resin material A in the cavity 5b and the void volume (filling allowable amount of the second resin material B, which will be described below) are given.

Following the filling operation of the first resin material A, the second resin material B is injected from the second cylinder 2 into the mold. The timing of injection of this second resin material B can be performed in a manner similar to operations performed in known sandwich molding methods.

When injecting the second resin material B, the first resin material A that has already been injected is gradually cooled and solidified in the parts that are in contact with the inner surfaces of each sprue, runner, and cavity, but the inside is still molten. The injected second resin material B is injected into the N2 cavity while spreading the first resin material A inside, which is in the molten state (see FIG. 5).

When the second resin material B is sufficiently injected into the second cavity 5b, the inside of the second cavity 5b is
A sandwich molded product having a layered structure similar to that obtained by the known sandwich molding method is obtained (No. 6).
(see figure). Note that a portion of the second resin material B slightly enters the bypass runner 4C side, but this does not affect the molded product.

As described above, the injection cycle of injection of the first resin material A and then injection of the second resin material B is completed, and a single material consisting only of the first resin material is contained in the first cavity 5a. A molded product with a single layer structure is molded, and inside the second cavity 5b, the second resin material B is used as the core, and the first resin material B is used as the core.
A molded article having a layered structure with resin material A as a surface layer is molded.

FIGS. 7 to 9 show the above-mentioned section 1. This figure shows the resin material injection pressure sequence of the injection device when performing the injection operation of the second resin material.

In these figures, Pl indicates the injection start point according to the injection pressure setting value of the first cylinder 1, Q indicates the injection completion point of the first cylinder 1, and P2 indicates the injection start point according to the injection pressure setting value of the second cylinder 2. ing.

In the example shown in FIG. 7, the bypass runner 4C in the example shown in FIG.
This sequence is suitable for cases where the diameter is sufficiently smaller than that of . In other words, if the bypass runner 4C is sufficiently thin and has a small cross-sectional area, the first resin material A that has already been injected will have been cooled and solidified when the second resin material B is injected. Even if the injection pressure of material A is released, the second resin material B remains inside the bypass runner 4c.
This is because almost no intrusion occurs.

On the other hand, when the diameter of the bypass runner 4c is relatively large, the first
It is appropriate to restrict the entry of the second resin material B into the bypass runner 4c without releasing the injection pressure of the second resin material A, and the example shown in FIG.
An example where the injection pressure of the second resin material is continued during the injection period of the second resin material % FIG. 9 shows an example of an intermediate case between FIGS. 7 and 8, respectively.

Figure 10 shows two types of molded products of different shapes molded from a single material made of the first resin material A, the core part of which is made of the second resin material B, and the surface part of which is made of the first resin material A. This shows another embodiment of the present invention in which one type of molded product having a layered structure is molded using a single molding die. first cavity 5a1,
The two first runners 4a1 and 4a2 of the runner plate 4 connected to the runner plate 5a2 (axes L-L, M-M1
A first sprue 3a (positioned above the axis) is provided to be offset from the first sprue 3a (positioned above), and the first sprue 38 The connection path from the first sprue 38 to one of the two first runners 4a2 is the bypass runner 4 to the second runner 4b.
It has the characteristic that it also serves as c.

FIG. 11 is for explaining another embodiment of the present invention, and in this figure, only the outline of the sprue, runner, and cavity, which are the voids in the molding die, are shown in a perspective view.

In this example, the first sprue 3a, the three first runners 4B1, 482, 4a
The first resin material A is injected through the tube 3. Note that 4C is a bypass runner, and a second
It is provided so that the first resin material is injected into the cavity.

With this configuration, three molded products made of a single resin material and a molded product with a layered structure of two types of materials can be molded using a single molding die through a cycle of molding operations. It becomes possible to mold.

The structure of the present invention is to provide a difference in the injection amount of the first resin material by providing a difference in the cross-sectional area of the paths as described in each of the above embodiments, and also to provide a difference in temperature of each path as described above. It is also possible to make a difference in the amount of the first resin material injected. This is because if the temperature of the mold is low, the viscosity of the resin material injected and flowing through the path will be high, and the flow resistance will be large, so that the amount of injection can be reduced as a result.

For this purpose, for example, a configuration can be exemplified in which heating means such as independent heaters are assembled in the parts where it is desired to make a difference in mold temperature, and these heating means are used to make a difference in the temperature of the desired route part. .

The present invention can also be implemented by setting the volume of the second cavity, which forms a sandwich molded product, to be sufficiently larger than the volume of the first cavity, which forms a molded product of a single material. That is, according to this configuration, even if the flow resistance of each path for injecting the first resin material into each of these cavities is approximately the same (there may be a difference that does not cause a problem), the first resin material At the time when the filling of the first resin material into the cavity is completed, the inside of the second cavity is not yet filled with the first resin material, so as a result, the second resin material This is because injection can be performed.

Specifically, for example, in the example shown in FIG. 1, the internal volume of the second cavity 5b is set to be sufficiently large compared to the internal volume of the first cavity 5a, and the cross-sectional area of the bypass path 4c is abbreviated as the first runner 4a. With the same configuration, when the filling of the first resin material is completed, the second cavity is filled with the second resin material.
It is possible to provide a filling margin for the resin material.

(Effects of the Invention) As explained above, according to the resin product molding apparatus of the present invention, a molded product made of a single material can be produced using a single molding die and in a single molding cycle. The effect is that it becomes possible to simultaneously mold a sandwich-structured molded product, and its usefulness is extremely high.

[Brief explanation of the drawing]

Figures 1 to 6 are diagrams for explaining the outline of the configuration and molding state of a molding apparatus according to an embodiment of the present invention, and Figures 7 to 9 are diagrams for explaining the configuration of a molding apparatus according to an embodiment of the present invention, and Figures 7 to 9 are diagrams for explaining the configuration of a molding apparatus according to an embodiment of the present invention. A diagram showing the injection sequence of the first and second resin materials, FIG. 10, and FIG. 11 are diagrams showing other embodiments of the present invention, respectively. A: First resin material B: First resin material 1: First cylinder la: Inlet 2: Second cylinder 2b: Inlet 3: Fixed plate 3a: First sprue 3b; Second sprue 4: Runner plate 4a: First runner 4b = Second runner 4C: Bypass runner 4g1: First gate 4g2: Second gate 5: Template 5a: First cavity 5b; Second cavity Fig. 1 Fig. 2 Fig. 3 Fig. 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9

Claims (1)

[Scope of Claims] At least one first cavity providing a space for molding a molded article made of a first resin material, and molding of a layered structure made of the first resin material and the second resin material. a first mold for injecting a first resin material into the mold; An injection device: a second injection device for injecting a second resin material into the mold, wherein the mold is configured to inject the first resin material into the mold. a first path provided to guide the resin material from the first injection device to the first cavity; and a first path branched from the middle of the first path to guide the first resin material to the second cavity. and a second path provided to guide the injected second resin material from the second injection device to the second cavity, respectively, inside the mold. , the second path is connected to the bypass path midway, so that the second path is connected to the bypass path through the bypass path.
cavity, and further connect the first to each of the above cavities.
The injection/distribution amount of the resin material is set to be relatively smaller from the bypass path to the second cavity side than from the first path to the first cavity side.