JPH09109193A - Mold for injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for injection molding which requires no expensive remodelling of large scale and can be used for multi-purposes simply by the replacement of a slide block without the necessity of a large amount of expense. SOLUTION: A setting section 15 for a replaceable slide block 14 with a parting face 14a on the side of a movable side template 11 is provided on the side of the movable side template 11 on the end of a cavity 13. Either of the slide block 14 with a runner 13b communicating with a side gate 13a on the end of the cavity 13s or a slide block with a tunnel gate communicating with a resin passage formed all through from the runner to the cavity by way of the inside of the slide block and the movable side template is mounted on the parting face 14a of the setting section 15, and molten resin is injected from the parting face of the runner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding die which can be used for various purposes, by changing a slide core and changing a gate position where a molten resin is injected.

[0002]

2. Description of the Related Art Conventionally, as a means for separating a runner, which is a passage for molten resin adhered to a molded product and released from the molded product after molding, a cross-sectional area of a communication port of a runner communicating with a cavity is made as small as possible. Also, a so-called pin gate has been used to facilitate the cutting from the molded product, or to provide a tunnel gate that communicates from the runner to the cavity so as to forcibly disconnect it when the mold is opened ( Plastic mold handbook, published by Nikkan Kogyo Shimbun, Inc., Japan Synthetic Resin Technology Association, Vol.
See pages 8 to 199).

[0003]

However, the conventional pin gate or tunnel gate as described above injects the molten resin into the cavity, and the opening / closing operation of the mold is used to forcibly separate the gate from the molded product. For structures,
In order for the gate to be easily cut, the communication opening to the cavity needs to have a very small cross-sectional area. Thus, if the communication opening of the gate has a very small cross-sectional area, the flow resistance of the molten resin injected into the cavity will rapidly increase at this communication opening. The problem is that it becomes difficult to fill the molten resin into the cavity, and in order to forcibly fill the cavity, the molten resin must be injected at high temperature and high pressure, which causes various problems in terms of quality and productivity. Will occur.

Therefore, the injection molding die provided with the above-mentioned conventional pin gate and tunnel gate has been restricted in terms of ensuring productivity and quality. For example, in the gate cutting method as described above, since the cutting opening seems to be peeled off due to the forced separation by pulling, there is often a problem that the appearance quality of the product is hindered. There is.

Further, the conventional pin gate and tunnel gate as described above have a structure fixedly provided at the end of the cavity, and therefore, in order to change product specifications and improve quality, etc. When changing the position of the gate, for example, when changing the position of the parting surface along with the size change of the product and the change of the gate position accordingly, it is necessary to modify the mold in the fixed side template. It is necessary to build up and finish by welding, and the movable side mold plate also involves machining such as shaving and finish processing, resulting in a large amount of cost, and in some cases from the design side of the product There is a problem that it cannot be modified.

The present invention has been made in view of the above problems, and an object of the present invention is to solve these problems and prevent the gate cut by the side gate or the side gate. In the case of molding of molded products, a slide block capable of gate cutting with a tunnel gate is replaceable so that any method can be supported, and even if the specification of the product is changed, the mold The present invention provides an injection-molding die that can be used for multiple purposes without requiring a large amount of cost by simply replacing the slide block without requiring large-scale modification.

[0007]

According to another aspect of the present invention, there is provided an injection molding die having a cavity formed by a movable side mold plate and a fixed side mold plate. On the plate side, the movable side mold plate side was used as a parting surface, and a replaceable slide block set part was provided, and in this set part, a runner communicating with the side gate at the cavity end was provided on the parting face. Either a slide block or a slide block that has a tunnel gate that penetrates through the slide block from the runner and communicates with a resin passage from the movable side template to the cavity is mounted, and the parting of the runner is performed. It is characterized in that the molten resin is injected from the surface.

[0008]

In the injection molding die of the present invention, the slide block set portion is provided with a runner communicating with the side gate at the cavity end on the parting surface, or a slide block from the runner. Molding in which the gate cut by the side gate or the side gate is not possible by mounting either of the slide blocks provided with the tunnel gate that penetrates the inside and communicates with the resin passage from the movable side mold plate to the cavity In the case of products, it is possible to cut the gate with a tunnel gate, and any method can be easily applied. Further, since the gate and the runner are held on the movable side mold plate side and opened, it is possible to take out the gate and the runner at the same time as the product. Furthermore,
Even if the specification of the product is changed, a large-scale modification of the mold is not required, and only the modification or replacement of the slide block can be performed without incurring a large cost.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a main part showing an example of an injection molding die of the present invention. In FIG. 1, a cavity 13 is formed in a mold 10 for injection molding by a movable side mold plate 11 and a fixed side mold plate 12, and a molten resin is injected into the cavity 13 to mold a molded product. Has become.

Movable mold plate 1 at the end of the cavity 13
A set portion 15 of a replaceable slide block 14 having the movable side mold plate side 11 as a parting surface 14a is provided on the first side, and the slide block 14 is provided in the set portion 15 in a set state.

On the parting surface 14a of the slide block 14, the side gate 1 at the end of the cavity 13 is provided.
A runner 13b communicating with 3a is provided, and a molten resin is injected into the runner 13b from a valve gate 16 provided in the stationary mold plate 12.

The slide block 14 is guided from the inside of the fixed-side mold plate 12 by the inclined pins 17 penetrating the slide block 14 to the outside along the movable-side mold plate 11 (direction orthogonal to the mold opening direction). It is designed to slide smoothly. Inside the movable side mold plate 11, there is provided a projecting pin 18 which is operated in parallel with the mold opening of the movable side mold plate 11, and by this projecting pin 18, a product molded by the cavity 13 in the side gate 13a. The more separated gate part is designed to be released from the runner.

FIG. 2 is a sectional view of the essential parts showing a modified example of the injection molding die of the present invention. In FIG. 2, the injection molding die 10A has the same structure and configuration as the injection molding die 10 shown in FIG. 1, but when the product end face is extended due to the change of the product specifications. This shows the correspondence on the die side.

That is, the slide block 14 forming a part of the end of the cavity 13 by extending the end surface of the product.
End surface 14b is retracted to the position of the end surface 14d, and this end surface 14d serves as a new parting surface. Along with this, the bottom surface 14c of the runner 13b of the slide block 14 is retracted to the position of the bottom surface 14e, and a modified slide block 14A is shown.

As described above, modifying the slide block 14 to form the slide block 14A can be easily performed in terms of processing, and a new slide block 14 can be manufactured and used. It is possible, and the runner gate is fixedly provided on the movable side template as in the past, and it has become possible to deal with large remodeling and without requiring a large amount of cost.

FIG. 3 and FIG. 4 are cross-sectional views of essential parts for explaining the operation of the injection molding die of the present invention. FIG. 3 shows a mode of the molded product immediately after the molten resin is injected into the cavity 13 and the molded product is molded and immediately before the mold is opened. When the molded product (13) in the cavity 13 is cooled and solidified and the opening process is started, the movable side mold plate 11 (shown in FIG. 1).
The mold opening is started.

By this mold opening, the slide block 14 slides outward guided by the inclined pin 18. At this time, the runner (13b) cooled and solidified by the runner 13b is forcibly moved in the direction orthogonal to the side gate 13a while being in close contact with the slide block 14. On the other hand, since the molded product (13) remains in close contact with the surface of the cavity 13 of the movable side mold plate 11, shearing force acts on the connection portion of the gate (13) with the molded product (13), As shown in FIG. 4, the gate (13) will be separated from the molded product (13). After that, the runner (13b) with the gate (13) is separated from the slide block 14 by the action of the projecting pin 18, and so-called gate cutting is completed.

Therefore, the molded product molded by the injection molding die of the present invention can improve the productivity of the product without requiring the work of gate cutting in the subsequent process.

FIG. 5 is a sectional view of a main part showing another example of the injection molding die of the present invention. The injection mold of the present invention corresponds to the case where injection molding cannot be performed by providing a side gate like the injection mold described in FIG. 1 above. Therefore, an equivalent slide coblock is provided with a tunnel gate. It is intended to form a molded product by communicating with the resin passage on the movable side mold plate side and injecting molten resin from the back surface of the product.

In FIG. 5, the injection molding die 20 includes
The cavity 2 is formed by the movable mold plate 21 and the fixed mold plate 22.
3 is formed, and a molten resin is injected into the cavity 23 to mold a molded product.

Movable mold plate 2 at the end of the cavity 23
A set portion 25 of a replaceable slide block 24 having the movable side mold plate side 21 as a parting surface 24a is provided on the first side, and the slide block 24 is provided in the set portion 25 in a set state. An end portion of the slide block 24 on the cavity 23 side is a parting surface 24d for forming a product end surface of the cavity 23.

A runner 24b is provided on the parting surface 24a of the slide block 24, and a side end of the runner 24b penetrates the inside of the slide block 24,
A tunnel gate 24c, which is provided on the movable side mold plate 21 and communicates with a resin passage 23a communicating with the cavity 23, is provided.

Therefore, the molten resin injected from the valve gate 26 provided on the stationary mold plate 22 and communicating with the runner 24b is supplied from the runner 24b to the tunnel gate 2 described above.
4c, and the resin 23a is further filled into the cavity 23 through the resin passage 23a to form a molded product.

Further, the slide block 24 is guided from inside the fixed side mold plate 22 by the inclined pins 27 penetrating the slide block 24, and outside along the movable side mold plate 21 (direction orthogonal to the mold opening direction). It is designed to slide smoothly.

Inside the movable side mold plate 21, there is provided a slide projecting pin 28 which operates in parallel with the mold opening of the movable side mold plate 21, and the operation of the slide projecting pin 28 causes the mold opening and Runner 24 that has been cooled and solidified
The runners in b are projected.

FIG. 6 shows the operation of the slide projecting pin 28. That is, the slide protrusion pin 28 is configured such that the head 28a at the tip thereof is slidably fitted in the guide 29. Therefore, when the lateral movement of the slide block 24 toward the outside is started along with the mold opening, the guide 29 follows the same while sliding between the head 28a and the runner by the slide projecting pin 28. The runner in 24b is pushed up and removed from the slide block 24.

Therefore, in the case of the injection molding die of the present embodiment, in the case of the product in which the injection molding from the side gate is impossible as in the above-mentioned embodiment, the slide block is simply replaced. Injection molding with a tunnel gate is possible, and products without side gates can be easily produced. Further, there is an advantage that the cost of the mold can be kept low.

[0028]

In the injection molding die of the present invention, the slide block set portion is provided with a runner communicating with the side gate at the end of the cavity on the parting surface, or the slide block By installing one of the slide blocks that has a tunnel gate that penetrates through the slide block and communicates with the resin passage from the movable side template to the cavity, the gate cut by the side gate or the side gate cannot be performed. In the case of a certain molded product, the gate can be cut with a tunnel gate, and any method can be easily applied. Further, since the gate and the runner are held on the movable side mold plate side and opened, it is possible to take out the gate and the runner at the same time as the product.
Further, even if the specifications of the product are changed, a large-scale modification of the mold is not necessary, and only the modification or replacement of the slide block can be performed without incurring a large cost. Therefore, it is suitable as a mold for injection molding.

[Brief description of the drawings]

FIG. 1 is a sectional view of essential parts showing an example of a mold for injection molding of the present invention.

FIG. 2 is a sectional view of a main part showing a modified example of the injection molding die of the present invention.

FIG. 3 is a sectional view of an essential part for explaining the operation of the injection molding die of the present invention.

FIG. 4 is a sectional view of an essential part for explaining the operation of the injection molding die of the present invention.

FIG. 5 is a cross-sectional view of a main part showing another example of the injection molding die of the present invention.

FIG. 6 is a cross-sectional view illustrating the operation of the slide protrusion pin shown in FIG.

[Explanation of symbols]

 10, 10A, 20 Mold for injection molding 11, 21 Movable side mold plate 12, 22 Fixed side mold plate 13, 23 Cavity (13) Molded product 13a, (13a) Side gate 13b, (13b), 24b Runner 14, 24 slide block 14a parting surface 14b, 14d, 24d end surface 14c, 14e bottom surface 15, 25 set part 16, 26 valve gate 17, 27 tilting pin 18 protruding pin 23a resin passage 24c tunnel gate 28 sliding protruding pin 28a head 29 guide

Claims (1)

[Claims] 1. An injection molding die in which a cavity is formed by a movable side mold plate and a fixed side mold plate, wherein the movable side mold plate side is a parting surface on the movable side mold plate side of the cavity end. A set part of replaceable slide block is provided, and in this set part, a slide block in which a parting surface is provided with a runner communicating with the side gate at the end of the cavity, or the runner penetrates through the slide block. , One of the slide blocks provided with a tunnel gate communicating with the resin passage extending from the movable side template to the cavity is mounted, and the molten resin is injected from the parting surface of the runner. A characteristic injection mold.