JP7657182B2 - Injection mould - Google Patents

Description

The present invention relates to an injection molding die that can suppress deformations such as curling that occur during demolding.

In resin molding using injection molds, high-temperature molten resin is poured into the mold and cooled to solidify the resin. During this process, the resin shrinks and bites into the mold, and if the resistance is high, deformation such as curling occurs when the product is released from the mold. To prevent this, a draft angle is provided to make the product easier to release from the mold, but when the product is relatively large, the amount of resin shrinkage also increases accordingly, and the draft angle alone is not enough to alleviate the resistance to release from the mold, resulting in deformation of the product such as curling.

Patent document 1 discloses an example of a mold that has a draft angle to make it easier to release the product.

JP 2007-98698 A

As mentioned above, in injection molding, the resin shrinks and sticks to the mold, which can cause deformation such as curling in the molded product when it is released.

The objective of the present invention is to provide an injection molding die that allows the die parts to follow the shrinkage of the resin, making it possible to produce high-quality molded products without causing deformation such as curling.

To achieve the above object, an example of the "injection molding die" of the present invention is as follows:
An injection molding die that is composed of a fixed die and a movable die and that injects resin,
a fixed insert of the fixed die, and a movable insert and a slide core of the movable die form a molding part;
A slide core holder divided into two parts is provided on the outside of the slide core,
A first slide core holder is connected to the slide core, a second slide core holder is fixed to a movable mold, a shoulder bolt is inserted into the first slide core holder to fix the first slide core holder movably relative to the second slide core holder, a coil spring is inserted into the shoulder bolt between the first slide core holder and the second slide core holder, and the coil spring presses the first slide core holder in the direction of resin contraction, so that the slide core moves in response to resin contraction of the molded product when the mold is opened .
The slide core is fixed when the mold is closed and moves in the direction of resin contraction when the mold is opened, thereby reducing the biting resistance caused by resin contraction and preventing deformation such as curling.

The present invention provides an injection molding die that allows the die parts to follow the shrinkage of the resin, making it possible to produce high-quality molded products without causing deformations such as curling.

Issues, configurations, and advantages other than those described above will become clear from the description of the embodiments below.

FIG. 2 is a cross-sectional view of a mold structure in a closed state according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a mold structure in a state in which the mold is midway open in an embodiment of the present invention. FIG. 2 is a cross-sectional view of the mold structure in the embodiment of the present invention when the mold is opened. FIG. 2 is an enlarged view of the vicinity of a slide block in the mold closed state of FIG. 1 . FIG. 3 is an enlarged view of the vicinity of a slide block in the middle of mold opening in FIG. 2 . FIG. 1 is a diagram showing an example of a molded product. FIG. 1 is a cross-sectional view of a conventional mold structure in a closed state.

Before describing the embodiments of the present invention, we will explain the injection molding die that is the premise of the present invention.

Figure 6 shows an example of a molded product formed using an injection molding die. The molded product 8 is box-shaped and has a hole or recess 80 on one side.

Figure 7 shows a schematic cross-sectional view of a conventional injection molding die for molding the molded product shown in Figure 6. The figure shows the die in a closed state.

The injection mold is composed of a fixed side 100 and a movable side 200 that moves relative to the fixed side. The components of the mold body fixed side 100 include a fixed side mounting plate 11 that is connected to the fixed side of the injection molding device. A fixed side mold plate 12 is attached to the fixed side mounting plate 11, and the combination of the fixed side mold plate 12 includes a sprue bushing 19, which is a part that guides the molten resin injected from the injection nozzle of the injection molding device to the molding part in the mold. The fixed side mold plate 12 is also equipped with a locking block 14 that pushes out the slide block 17 attached to the mold body movable side 200 when the mold is closed, and an angular pin 13 that moves the slide block 17 to the outside of the mold when the mold is opened.

The components of the movable side of the mold body 200 include a movable side mounting plate 15 that is connected to the movable side of the injection molding device, and a movable side mold plate 16 that is attached to it. The movable side mold plate 16 is equipped with a slide block 17 that slides as the movable side 200 moves. In the figure, the reference numeral 18 indicates an angular pin insertion hole through which the angular pin 13 passes.

The fixed insert 1 on the fixed mold plate 12, the movable insert 2 on the movable mold plate 16, and the slide core 3 on the slide block 17 form the molded part, and when the mold is closed, high-temperature molten resin is poured in through the sprue bushing 19 and cooled and solidified to form the molded product 8. During this process, the resin contracts and sticks to the mold, causing deformation such as curling when demolded, especially in the holes or recesses 80.

The present invention solves this problem by allowing the mold parts to follow the shrinkage of the resin, making it possible to provide high-quality molded products without deformation such as curling.

The following describes an embodiment of the present invention with reference to the drawings. However, the present invention should not be interpreted as being limited to the description of the embodiment shown below. Those skilled in the art will easily understand that the specific configuration can be changed without departing from the concept or spirit of the present invention.

Figure 1 shows a cross-sectional view of the mold structure in a closed state in an embodiment of the present invention. Figure 2 shows a cross-sectional view of the mold structure in the middle of mold opening, with the movable side 200 moved slightly downward. Figure 3 shows a cross-sectional view of the mold structure in the finished mold opening state, with the movable side 200 moved further downward.

As in FIG. 7, the injection mold is composed of a fixed side 100 and a movable side 200 that moves relative to the fixed side. The components of the mold body fixed side 100 include a fixed side mounting plate 11 that is connected to the fixed side of the injection molding device. The fixed side mounting plate 11 is attached to a fixed side mold plate 12, and the fixed side mold plate 12 is also equipped with a sprue bushing 19, which is a part that guides the molten resin injected from the injection nozzle of the injection molding device to the molding part in the mold. The fixed side mold plate 12 is also equipped with a locking block 14 that pushes the slide block 17 attached to the mold body movable side 200 toward the center when the mold is closed, and an angular pin 13 that moves the slide block 17 to the outside of the mold when the mold is opened.

The components of the movable side of the mold body 200 include a movable side mounting plate 15 that is connected to the movable side of the injection molding device, a movable side mold plate 16 that is attached to the movable side mounting plate 15, and an ejector pin (not shown) that ejects the molded part. The movable side mold plate 16 is equipped with a slide block 17 that slides left and right as the movable side 200 moves. In the figure, the reference numeral 18 indicates an angular pin insertion hole through which the angular pin 13 passes.

The operation of the mold shown in FIGS. 1 to 3 will now be outlined.
In the mold open state shown in Fig. 3, when the movable side 200 is moved upward toward the fixed side 100, the slide block 17 slides toward the center, guided by the angular pin 13, as shown in Fig. 2. Then, the inclined surface of the locking block 14 comes into contact with the inclined surface of the slide block 17 , and the slide block 17 is pressed toward the center by the inclined surface of the locking block 14. Then, the movable side insert 2 attached to the movable side mold plate 16, the slide cores 3 on both sides thereof, and the fixed side insert 1 of the fixed side mold plate 12 form a molded part.
In the mold closed state shown in FIG. 1, molten resin is introduced from the sprue bush 19 into the molding portion in the mold and allowed to solidify.
After the molten resin has solidified, the movable side 200 is moved downward in a direction away from the fixed side 100, as shown in Fig. 2 and Fig. 3. The slide block 17 is moved by being guided by the angular pin 13, and the slide core 3 is opened. Then, the molded product 8 on the movable side 200 is pushed out and removed.

Next, the characteristic configuration of the resin molding die of this embodiment will be described. Figure 4 shows an enlarged view of the right slide block 17 and its vicinity in the mold closed state of Figure 1. Also, Figure 5 shows an enlarged view of the right slide block 17 and its vicinity in the mold halfway open state of Figure 2.

The fixed side insert 1 of the fixed side mold plate 12, the movable side insert 2 attached to the movable side mold plate 16, and the slide core 3 of the slide block 17 form a molding section (mold) for molding the molded product 8. The outside of the slide core 3 has a slide core holder a (first slide core holder) 4 and a slide core holder b (second slide core holder) 5, which are divided into two parts, upper and lower. The slide core 3 is connected to the slide core holder a4 with a bolt (not shown). The slide core holder a4 located at the top is connected to the slide core holder b5 with a shoulder bolt 6 so that it can move by a gap of 9. A coil spring 7 is inserted into the shoulder bolt 6, which pushes the slide core holder a4 upward in a direction away from the slide core holder b5. The head of the shoulder bolt 6 acts as a stopper and regulates the upper position of the slide core holder a4. In other words, the shoulder bolt 6 and the coil spring 7 work to move the slide core holder a4 away from the slide core holder b5 by a gap of 9.

When the mold is closed to pour the molten resin into the mold as shown in FIG. 4, the fixed side parts press the slide core 3 and the slide core holder a4 from above, so the coil spring 7 is bent and the slide core holder a4 and the slide core holder b5 are in a mated state. In this state, the molten resin is poured into the molding part. When the mold is opened after the molten resin has solidified, the movable side moves downward as shown in FIG. 5, and the slide core 3 and the slide core holder a4 are released from the holding of the fixed side parts. Then, the slide core 3 and the slide core holder a4 connected by the bolt are raised by the force of the coil spring 7 by the gap 9 between the slide core holder a4 and the head of the shoulder bolt 6. When the molten resin is cooled and solidified, as shown in the figure, a force acts upward in the direction of resin contraction. The slide core 3 is raised relative to the movable side mold plate 16 , so that it follows the contraction of the molded product 8, and the mold release resistance due to the bite of the resin is alleviated, and deformation such as curling can be prevented. In particular, deformation such as curling in the holes and recesses 80 in a direction intersecting the resin contraction direction can be prevented.

The injection molding die of this embodiment allows the slide core 3 that forms the molding portion (mold) to move in response to resin contraction, and by making the slide core 3, which is a die part, follow the resin contraction when the die is opened, it is possible to provide a high-quality molded product without causing deformation such as curling.

1...Fixed side insert 2...Movable side insert 3...Slide core 4...Slide core holder a
5...Slide core holder b
6... shoulder bolt 7... coil spring 8... molded product,
9...Stroke amount (gap) by which the slide core rises
11...Fixed side mounting plate 12...Fixed side mold plate 13...Angular pin 14...Locking block 15...Movable side mounting plate 16...Movable side mold plate 17...Slide block 18...Angular pin insertion hole 80...Hole or recess in molded product 100...Mold body fixed side 200...Mold body movable side

Claims (4)

An injection molding die that is composed of a fixed die and a movable die and that injects resin,
a fixed insert of the fixed die, and a movable insert and a slide core of the movable die form a molding part;
A slide core holder divided into two parts is provided on the outside of the slide core,
an injection molding die comprising: a first slide core holder coupled to the slide core; a second slide core holder fixed to a movable die; a shoulder bolt inserted into the first slide core holder to fix the first slide core holder movably relative to the second slide core holder; a coil spring inserted into the shoulder bolt between the first slide core holder and the second slide core holder; the coil spring pressing the first slide core holder in the direction of resin contraction ; and a slide core moved in response to resin contraction of a molded product when the die is opened . 2. The injection mold according to claim 1 ,
The head of the shoulder bolt restricts the movement of the first slide core holder. 2. The injection mold according to claim 1 ,
An injection molding die in which the slide core and the first slide core holder are pressed by the fixed-side die when the die is closed, and the pressure by the fixed-side die is released when the die is opened, so that the slide core follows the resin contraction. 2. The injection mold according to claim 1,
The molded product is an injection molding die having a hole or a recess on the side surface.

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