JP2000000850A - Metal mold for injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent a molding fault of a molding by simply controlling a charging amount of a material to be charged in each cavity. SOLUTION: The mold 10 for injection molding comprises first and second molds 11, 12. The mold 12 has secondary cavities 18, 19 formed therein, and nozzles 26A, 27A of cylinders 26, 27 disposed oppositely to the cavities 18, 19. The cylinders 26, 27 are provided to pressure charge a material from an injecting unit 21 in the cavities 18, 19 in such a manner that charging amounts of the cavities 18, 19 are independently controlled at respective cavities 18, 19 by pressurizing units 40, 41 connected to a controller.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for injection molding, and more particularly to an improvement in the structure of a multi-cavity mold or a set-cavity mold.

[0002]

2. Description of the Related Art There has been known an injection molding die capable of simultaneously molding a large number of resin products using a single injection device. This injection molding die includes, for example, one shown in FIG. Here, FIG. 3 shows a schematic configuration of a mold for secondary molding in insert molding. In this figure, a mold 50 includes first and second molds 52 and 53, and cavities 56 and 57 in which the primary molded product 14 can be set are provided at two upper and lower locations in the figure. In the second mold 53, secondary cavities 58, 59 capable of being filled with a material for secondary molding are formed so as to be continuous with the primary molded article 14 in a state where the mold 50 is closed. . The material 12 injected by the injection device 63 is supplied to the secondary cavities 58 and 59 via the runner 64. A spool 65 capable of receiving the nozzle tip of the injection device 63 is formed on the inlet side of the runner 64, and a check valve 66 for preventing a backflow of the material 12 passing through the runner 64 is provided in the middle of the runner 64. Is provided. Here, the material 12 filled in the secondary cavities 58 and 59 is cured by heating or cooling and then taken out as a molded product as shown in FIG. In addition, each cavity 56-5
9 and a plurality of cavities 56-5.
There is also known a set-up die that makes the shapes of the moldings 8 different from each other and enables molding of a large number of molded products having different shapes.

[0003]

However, in the injection molding die 50, the secondary cavities 58, 5 are provided.
9 are communicated with each other by the runner 64, so that if a pressure loss occurs due to damage to one of the secondary cavities 58, 59, an extra material flows into one of the secondary cavities 58, 59, Insufficient material filling occurs in the other secondary cavities 58 and 59, resulting in molding failure of the molded product. Therefore, when the secondary cavities 58 and 59 are damaged, the mold 50 needs to be replaced or repaired inevitably, resulting in a great deal of trouble.

In the case where a mold having a larger number of cavities is employed, if the mold is formed so as to minimize the length of the runner to each secondary cavity, each of the secondary cavities is reached. Since the flow distance of the material is different, the pressure loss in each path is different, and the material is insufficiently filled or overfilled in some of the secondary cavities. Therefore, it is necessary to change the cross-sectional area of each runner step by step, or to make the lengths of the runners up to the respective secondary cavities all the same, and the mold becomes complicated, and it takes time to make the mold. There are inconveniences. Further, even if the mold is not complicated, it is possible to cope with the problem by introducing an injection device capable of controlling the injection conditions of the material in multiple steps, but this causes a disadvantage that the entire device becomes large.

Further, when a set-up mold is employed, it is more difficult to adjust the cross-sectional area of each runner and to adjust the flow distance from the injection device to each cavity, and the above-mentioned disadvantages become more apparent. . In addition, in the above-mentioned example, the inconvenience in the secondary molding is particularly shown, but the same applies to the case where the primary molded article 14 is injection-molded.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of such inconvenience, and an object of the present invention is to make it possible to easily control the amount of material to be filled in each cavity and to provide a molded product. It is an object of the present invention to provide an injection molding die capable of effectively preventing molding defects.

[0007]

To achieve the above object, the present invention provides an injection mold having a plurality of cavities, into which a material is injected to form a large number of molded articles simultaneously. An injection amount adjusting means is provided for each of the cavities, and an injection amount of the material injected from the injection amount adjusting means is provided so as to be independently controllable for each cavity. According to such a configuration, since the injection amount of the material injected into each cavity can be controlled, even if some cavities are damaged, the other cavities are not affected by the cavities. Insufficient material filling of the cavity can be effectively prevented, and high quality molding can be achieved. In addition, even if the flow distance of the material to each cavity is different, it is possible to uniformly fill the material in each cavity by changing the injection conditions into each cavity. Can be effectively prevented. Furthermore, even when a set mold is employed, the injection conditions for each cavity can be easily adjusted.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, it is preferable that the injection amount adjusting means is buried in the mold, and a nozzle of the injection amount adjusting means is arranged facing a corresponding cavity. By doing so, the material injected from the injection amount adjusting means can be directly injected into the cavity, so that the injection amount adjusting means with a low injection pressure can be employed, which promotes miniaturization of the entire apparatus. be able to.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an insert molding die will be described below with reference to the drawings.

FIG. 1 is a schematic explanatory view of a main part of a secondary molding die into which a primary molded product is inserted.
In this figure, an injection mold 10 is a multi-cavity mold capable of simultaneously molding two molded articles having the same shape, and is constituted by first and second molds 11 and 12. ing. The first mold 11 is located on the upper side (right side in FIG. 1).
Are provided with two primary cavities 16 and 17 for receiving a bottomed primary molded article 14 (see FIG. 2). Here, the primary molded product 14 in the primary cavities 16 and 17 has an end surface 14A on the opening side facing the second mold 12, that is, facing the mold parting line PL.

In the second mold 12, secondary cavities 18 and 19 are formed so as to be continuous with the end surface 14A of the primary molded product 14 when the mold 10 is closed. In the secondary cavities 18 and 19, a material 22 injected from an injection device 21 provided adjacent to the mold 10 (see FIG. 2).
Is filled through the runner 24 and the injection cylinders 26 and 27. Here, the material 22 is
Although not particularly limited, a silicone resin or the like as a sealing material can be exemplified.

The runner 24 includes a first runner 29 communicating with a spool 33 and second runners 30 and 31 branched from the first runner 29 and connected to the injection cylinders 26 and 27, respectively. . As a result, the material 22 injected onto the spool 33 by the injection device 21 passes through the runner 24 and the injection cylinder 2
6 and 27, respectively. Here, a check valve 40 for preventing the backflow of the material 22 is provided in the middle of the second runners 30 and 31. Runner 2
The four regions are heated or cooled according to the type of the material 22, and are controlled at a predetermined temperature so as not to hinder the flow.

Nozzle 2 of the injection cylinders 26 and 27
6A and 27A are arranged facing the secondary cavities 18 and 19, and by the operation of the plungers 37 and 38,
The material 22 from the second runners 30 and 31 can be directly supplied to the secondary cavities 18 and 19 under pressure. Here, by changing the strokes of the plungers 37 and 38, it is possible to change the injection amount of the material 22 into the secondary cavities 18 and 19. The plungers 37, 38
The operation and stroke of are controlled independently from each other by pressurizing devices 40 and 41 connected to a controller (not shown). Here, plunger 3
The injection cylinders 26 and 27 including the pressure chambers 7 and 38 and the pressurizing devices 40 and 41 constitute injection amount adjusting means, respectively.

Although the injection device 21 is not particularly limited, it mixes the two liquids A and B to generate a material 22 and can inject the material 22 at a predetermined timing. Not movable through mold 11
Is provided so as to be able to advance and retreat.

Next, the operation of the injection molding apparatus 10 will be described.

First, after the primary molded article 14 is molded in the primary cavities 16 and 17, the mold is replaced and the mold is clamped by the secondary molding die 12. Next, the tip of the nozzle of the injection device 21 is received by the spool 33, and the material 22 is supplied to the runner 2.
4 and the material 22 is supplied to injection cylinders 26 and 27. At this time, the supply amount of the material 22 to the injection cylinders 26 and 27 is independently controlled by the pressurizing devices 40 and 41. Then, the plungers 37, 38 are operated by the operation of the pressurizing devices 40, 41, and the secondary cavities 1
8 and 19 are filled with a material 22 under pressure. Then, the material 22
Is heated and cooled or hardened in the secondary cavities 18 and 19, the mold is opened, and the molded article is ejected, whereby a molded article as shown in FIG. 2 is obtained.

Therefore, according to such an embodiment, since the material can be injected independently into the secondary cavities 18 and 19, even if the secondary cavities 18 and 19 are damaged, each secondary The cavities 18 and 19 can be properly filled with the material 22, and a high-quality molded product can be obtained.

Also, since the injection cylinders 26 and 27 facing the secondary cavities 18 and 19 are arranged, the injection device 2
The injection pressure of 1 applies the material 22 to the injection cylinders 26, 27
In addition, a small injection device 21 can be employed, and the length of the runner 24 can be minimized, so that materials used can be saved.

In the above embodiment, the injection cylinder 2
Although the case where the molds 6 and 27 are embedded in the mold 10 has been illustrated and described, the present invention is not limited to this, and may be provided separately from the mold 10. However, in the case of the above-described embodiment, since a part of the mold 10 can be used, the size of the entire apparatus can be reduced.

Further, the present invention may be applied to a set mold and a mold in which a large number of secondary cavities are formed. In this case, it is not necessary to adjust the cross-sectional area and length of the runner, and the injection conditions for each secondary cavity can be adjusted more easily.

Further, in the above-described embodiment, the configuration in which one injection cylinder is provided for one unit of the secondary cavity is illustrated and described. However, the present invention is not limited to this, and a plurality of injection cylinders are provided for one unit of the secondary cavity. A configuration in which a cylinder is provided may be employed. In this case, a high-quality multilayer molded product can be obtained.

In addition, the configuration of each unit of the apparatus according to the present invention is not limited to the illustrated configuration example, and various changes can be made as long as substantially the same operation is achieved.

[0023]

As described above, the injection amount adjusting means is provided for each cavity, and the injection amount of the material injected from the injection amount adjusting means is provided so as to be independently controllable for each cavity. Unaffected by the condition of the cavity,
Each cavity can be filled with a material under stable conditions, and high-quality molding can be performed.

Further, since the injection amount adjusting means is embedded in the mold and the nozzle of the injection amount adjusting means is arranged facing the corresponding cavity, the injection amount adjusting means with a low injection pressure can be employed. In addition, miniaturization of the entire device can be promoted.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an injection mold according to an embodiment.

FIG. 2 is a schematic perspective view of a molded product formed by the injection molding die of FIG. 1;

FIG. 3 is a schematic explanatory view of a conventional injection mold.

[Explanation of symbols]

 Reference Signs List 10 injection molding die 18 secondary cavity 19 secondary cavity 22 material 26 injection cylinder 26A nozzle 27 injection cylinder 27A nozzle 40 pressurizing device 41 pressurizing device

Claims (2)

[Claims] 1. An injection molding die having a plurality of cavities, into which a material is injected to form a large number of molded products at the same time, wherein injection amount adjusting means is provided for each of the cavities, An injection molding die, wherein an injection amount of a material injected from the injection amount adjusting means is provided so as to be independently controllable for each cavity. 2. The injection molding metal according to claim 1, wherein said injection amount adjusting means is embedded in said mold, and a nozzle of said injection amount adjusting means is arranged facing a corresponding cavity. Type.