JP3745350B2 - Injection mold and injection molding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a composite molding technique in which two or more kinds of resin materials having different compositions or colors are injected and integrated in a mold to obtain a molded product.
[0002]
[Prior art]
As a conventional example of general composite molding, a schematic configuration for molding a composite portion in an injection mold is shown in FIG. In FIG. 4, 16 is a cavity filled with the first resin, 17 is a cavity filled with the second resin, and 18 is a movable core that opens and closes the cavity 17. The movable core 18 is provided with a groove 18a for forming a convex shape on the first resin side at the junction of the first resin and the second resin, and a convex portion on the mold body 20 side in the groove 18a. The movable core 18 is slidably supported with respect to the mold main body 20 by fitting the 20a.
[0003]
In the above configuration, in order to obtain a molded article made of multiple materials and multiple colors, the first resin is injected into the cavity 16 with the cavity 16 closed by the movable core 18, cooled and solidified, and then the movable core 18. The cavity 17 is made, the second resin is injected into the cavity 17 and cooled and solidified (Patent Document 1).
[0004]
A method of providing a blocking means between the first and second resins is also known. This is because the passage is blocked by the blocking means, the molding materials of different colors are simultaneously injected and filled in the divided cavities, and the injection of the resin passage in the cavity is released immediately before the injection is completed. It is made to complete (patent document 2).
[0005]
Also, in the case of composite molding in which individually molded products are inserted into a mold for integration, an insert type injection mold or the like is known.
[0006]
[Patent Document 1]
JP-A-5-104575 [Patent Document 2]
JP-A-8-020040.
[0007]
[Problems to be solved by the invention]
However, in the case of using an injection mold in the conventional multi-material, multi-color composite molding as shown in FIG. 4, the mold has an appropriate shape for generating a cavity for filling the second resin. The movable core 18 is inserted, and after the first resin reaches a predetermined filling amount, the movable core 18 is retracted to fill the second resin. In this case, as shown in FIG. 4, when the movable core 18 is provided with a groove 18 a for forming a convex shape on the first resin, the resin material is out of the cavity when the first resin is injected into the cavity 16. In order to enter the groove portion of the portion 18b that is positioned, a convex portion 20a that fits into the groove 18a is provided on the mold body side to prevent the resin from entering the portion outside the cavity of the groove 18a. I have to leave.
[0008]
Therefore, in the case of a mold having a configuration as shown in FIG. 4, since it is necessary to provide a groove 18a and a convex portion 20a to be precisely fitted, the mold processing becomes complicated and expensive as compared with a normal mold. Become a mold. Further, since it is necessary to precisely fit the groove 18a and the convex portion 20a, for example, when trying to change the depth dimension of the groove 18a of the movable core 18, the convex shape on the mold body 20 side is provided. It is necessary to change the shape of the part 20a, and flexibility such as a shape change is not possible. For this reason, when trying to modify a die for the purpose of design change or mass productivity, it is difficult to remodel, further accuracy cannot be maintained, and it takes a lot of time to modify the die, making it normal for mold production. There was a problem that the cost would be significantly higher than that. In particular, when the accuracy is lowered, it may cause a problem affecting the quality.
[0009]
Further, in a mass production molding process, in the case of a mold having a movable core, it is necessary to pay attention to a sliding failure in mold alignment when the movable core part is operated, and there is a problem that a molding cycle must be extended.
[0010]
In the method of injecting and molding two color molding materials at the same time, the blocking means is removed immediately before the completion of injection, so the injected material flows and mixes at the junction, so the shape of the junction There is also a problem that the desired constant shape cannot be obtained.
[0011]
Therefore, the present invention has been made in view of the above-described problems, and the object thereof is to make a joining portion of a multi-material and a multi-color material in a certain shape easily and inexpensively in an injection mold in composite molding. It is to be able to mold.
[0012]
[Means for Solving the Problems]
In order to solve the above-described problems and achieve the object, an injection mold according to the present invention is for injecting two or more types of resin materials and integrating them in the mold to produce a molded product. In an injection mold, a movable part having a cavity for molding the molded product and a groove part for molding a convex shape at a joint part of the two or more types of resin materials, which is disposed so as to be able to advance and retreat in the cavity. A mold member having a core and a flat portion that abuts an end surface of the movable core where the groove portion is formed, and the movable core slides in the longitudinal direction of the groove portion along the flat portion. To do.
[0013]
Further, in the injection mold according to the present invention, when the movable core is retracted from the cavity, a tip portion thereof slightly protrudes into the cavity.
[0014]
The injection molding method according to the present invention is an injection molding die for producing a molded product by injecting two or more kinds of resin materials and integrating them in a mold, and molding the molded product. A movable core having a groove portion for forming a convex shape at a joint portion of the two or more types of resin material, and a groove portion for forming the convex shape is formed in the cavity. An injection molding method using an injection mold including a mold member having a flat portion that comes into contact with the end face, wherein the movable core is advanced into the cavity to form the first cavity having the convex shape Then, after filling the first resin into the first cavity and solidifying the resin, the movable core is slid in the longitudinal direction of the groove portion along the flat portion to be retracted from the cavity, Front end And forming a second cavity is slightly protrude into the cavity.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.
[0016]
FIG. 1 is a side sectional view showing a configuration of an embodiment of an injection mold according to the present invention.
[0017]
The mold shown in FIG. 1 is an injection mold using a hot runner. 1 is a fixed side mounting plate, 2 is a manifold block, 3 is a fixed side mold plate, 4 is a moving side mold plate, and 5 is an ejector. Reference numeral 6 denotes a moving side mounting plate. 7a is a first resin manifold, 7b is a second resin manifold, 8a is a first resin valve gate, 8b is a second resin valve gate, and 102a is a product portion made of the first resin. The cavity 102b represents the cavity of the product portion made of the second resin.
[0018]
In the above configuration, the fixed side mounting plate 1 is fixed to the fixed side platen of the main molding machine (not shown), and the moving side mounting plate 6 is fixed to the moving side platen using fastening means such as bolt fastening. The first resin injected from the main molding machine passes through the manifold 7a and the valve gate 8a provided in the manifold block 2, and is filled in the first cavity 102a. After the first resin is solidified to some extent, the movable core 30 described later is retracted from the second cavity 102b, the second resin is injected, passes through the manifold 7b and the valve gate 8b, and enters the second cavity 102b. Filled. Then, the first resin that has already solidified to some extent functions as a wall of the second resin merge portion in the merge portion of the first resin and the second resin, and the first resin and the second resin are By bonding, a composite molded product composed of the first resin and the second resin is molded.
[0019]
FIG. 2 is a diagram showing the shape of a molded product molded by the mold according to the present embodiment.
[0020]
In FIG. 2, 11 is a first product portion made of a first resin, 12 is a second product portion made of a second resin, and 13 is a merge of the first resin and the second resin. Indicates the junction. The first product portion at the junction 13 is formed with a convex portion 11 a for increasing the bonding force between the first product portion 11 and the second product portion 12.
[0021]
5 and 6 are perspective views showing the peripheral structure of the cavity of the injection mold according to this embodiment. FIG. 5 shows a state where the movable core protrudes into the cavity of the mold, and FIG. 6 shows a state where the movable core is retracted from the cavity.
[0022]
5 and 6, a cavity 102 for molding a product is provided in the fixed-side mold plate 3 of the mold, and the cavity 102 is a first cavity for molding the first product portion 11. 102 a and a second cavity 102 b for molding the second product portion 12. In the second cavity 102b, the movable core 30 for molding the shape of the joining portion of the first resin (first product portion 11) and the second resin (second product portion 12) is provided in the cavity 102b. Are arranged so as to be able to advance and retreat in the vertical direction in the figure.
[0023]
7 and 8 are perspective views of the movable core shown in FIGS. 5 and 6 extracted. FIG. 7 shows a state where the movable core 30 protrudes into the cavity, and FIG. 8 shows a state where the movable core is retracted from the cavity.
[0024]
7 and 8, the movable core 30 is formed with a groove 30a for molding the convex portion 11a of the first product portion 11 in FIG. The groove 30a extends downward in the figure along the movable core 30, and its bottom 30b is formed at a position where it is flush with the upper surface 50a of the insert piece 50 with the movable core 30 protruding into the cavity. ing.
[0025]
Further, the movable core 30 has a rectangular parallelepiped portion 30c at the lower portion thereof, and this rectangular parallelepiped portion 30c is supported by the insertion piece 50 so as to be movable in the vertical direction in the figure.
[0026]
In addition, the contact surface 50b of the insert piece with which the right end surface on which the groove 30a of the movable core 30 is formed is not formed with a convex portion that fits into the groove 30a as in the conventional case, and is processed into a flat surface. Has been. At this time, when the groove 30a is formed over the entire length in the vertical direction of the movable core 30, the first resin is a portion outside the cavity of the groove 30a when the first resin is injected into the first cavity 102a. It will approach to. However, in this embodiment, as shown in FIG. 7, since the groove 30a has the bottom 30b, the first resin injected into the first cavity 102a leaks out of the first cavity 102a. There is no.
[0027]
Further, in a state where the movable core 30 is retracted from the second cavity 102b, as shown in FIG. 8, the tip of the movable core 30 slightly protrudes from the upper surface 50a of the insertion piece 50, and also in the second cavity 102b. It protrudes slightly. By doing so, even when the movable core 30 is retracted from the cavity, the convex portion 11a of the first product portion 11 shown in FIG. 2 is in a state of covering the upper end portion of the groove 30a. When the second resin is injected into the second cavity 102b, the second resin does not enter the groove 30a. Therefore, in this embodiment, it is not necessary to provide a convex portion that fits with the groove 30a, which has been conventionally required, on the contact surface 50b of the insert piece 50.
[0028]
Thus, in this embodiment, since it is not necessary to provide a convex part in the contact surface 50a of the insertion piece 50, it can be made into a flat surface. Even when changing the above, it is only necessary to replace the movable core 30 without changing the shape of the insert piece 50. Thereby, the freedom degree with respect to a design change etc. improves and the cost concerning manufacture of a metal mold | die can be reduced. Moreover, since it is not necessary to process a convex part in the contact surface 50a of the insertion piece 50, the processing cost of a metal mold | die can be reduced.
[0029]
Next, the molding operation by the injection mold configured as described above will be described.
[0030]
First, as shown in FIG. 5, with the movable core 30 protruding into the second cavity 102b, the first resin is injected into the first cavity 102a. The injected first resin forms the product portion 11. When the first resin is solidified to some extent, the movable core 30 is withdrawn from the second cavity 102b, and the first resin solidified to some extent is allowed to function as a wall at the junction 13.
[0031]
Next, a second resin is filled into the second cavity 102b formed after the movable core 30 is retracted. At this time, the second resin merges with the wall surface formed of the first filled resin that functions as a wall at the merge point 13. Since the first resin and the second resin are still joined together in a hot state, a moderately tight bonding surface is formed.
[0032]
Then, after the first resin and the second resin are completely solidified, the mold is opened and the molded product is taken out.
[0033]
FIG. 3 is a view showing a sealed container as an example of a molded product molded using the injection mold according to the present embodiment.
[0034]
In FIG. 3, reference numeral 14 denotes a sealed container body made of the first resin, and 15 denotes a tab made of the second resin. In this embodiment, after injecting a black resin material and molding the sealed container body 14, an orange material is used as the second resin material, the tab 15 is molded, and the black sealed container body 14. And two-color molding in which the orange tab 15 is integrated.
[0035]
Note that the present invention can be applied to modifications or variations of the above-described embodiment without departing from the spirit of the present invention.
[0036]
【The invention's effect】
As described above, according to the present invention, in a mold for injection molding in composite molding, it is possible to easily and inexpensively mold a joining portion of multi-materials and multi-color materials into a certain shape.
[Brief description of the drawings]
FIG. 1 is a side sectional view showing a configuration of an embodiment of an injection mold according to the present invention.
FIG. 2 is a view showing the shape of a molded product molded by the mold according to one embodiment.
FIG. 3 is a view for explaining an example of a sealed container formed by the mold of one embodiment.
FIG. 4 is a view for explaining a conventional composite mold.
FIG. 5 is a perspective view showing a peripheral structure of a cavity of an injection mold according to an embodiment.
FIG. 6 is a perspective view showing a peripheral structure of a cavity of an injection mold according to an embodiment.
7 is a perspective view showing a part of the movable core shown in FIGS. 5 and 6. FIG.
FIG. 8 is a perspective view showing a part of the movable core shown in FIGS. 5 and 6 in an extracted manner.
[Explanation of symbols]
1 fixed side mounting plate 2 manifold block 3 fixed side template 4 moving side plate 5 ejector plate 6 moving side mounting plate 7a first resin manifold 7b second resin manifold 8a first resin valve gate 8b first Second resin valve gate 11 First product part 12 Second product part 13 Joining point 14 Container body 15 made of first resin Tab 16 made of second resin Filled with first resin Cavity 17 Cavity 18 filled with second resin Movable core 30 Movable core 50 Inserting piece 102 Cavity 102a First cavity 102b Second cavity

Claims (3)

In an injection mold for producing a molded product by injecting two or more kinds of resin materials and integrating them in a mold,
A cavity for molding the molded article;
A movable core disposed in the cavity so as to be capable of advancing and retracting, and having a groove for forming a convex shape at a joint of the two or more types of resin materials;
A mold member having a flat surface portion that comes into contact with the end surface on which the groove portion of the movable core is formed ;
An injection mold , wherein the movable core slides in the longitudinal direction of the groove portion along the flat portion .   2. The injection mold according to claim 1, wherein when the movable core is retracted from the cavity, a tip portion thereof slightly protrudes into the cavity. An injection mold for injecting two or more kinds of resin materials and integrating them in a mold to produce a molded product, a cavity for molding the molded product, and advancing and retreating in the cavity A mold member having a movable core having a groove portion for forming a convex shape at a joint portion of the two or more types of resin materials, and a flat portion that comes into contact with an end surface of the movable core where the groove portion is formed. An injection molding method using an injection mold comprising:
The movable core is advanced into the cavity to form a first cavity having the convex shape, and after filling the first cavity with the first resin and solidifying the resin, the movable core is moved to the plane. An injection molding method characterized in that the second cavity is formed by sliding along the part in the longitudinal direction of the groove part and retracting from the cavity and slightly projecting the tip part into the cavity .

Images