JPH07256682A - Resin molding method and resin molding die assembly - Google Patents

Abstract

PURPOSE:To contrive to shorten the high pressure gas releasing time from the interior of a molding article and also enhance the productivity of the resin molded article in the method for producing the resin molded article having hollow port by charging high pressure gas in the interior of the resin molded article and the mold assembly therefor. CONSTITUTION:Simultaneously with or before or after the releasing of high pressure gas 8 through a sprue into the air, a gas releasing pin 10 provided on a movable insert 4 is entered within a molded article 6 so as to release the high pressure gas 8 within the molded article 6 through an vent hole 15 provided within the pin into the air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for filling a resin molded product with a high pressure gas to produce a resin molded product having a hollow portion, and a die apparatus used for the method.

[0002]

2. Description of the Related Art In recent years, in the manufacture of resin molded products such as plastic products, high hollow molding has been performed in which a movable insert is operated while the high pressure gas is filled inside the molded product to provide a very large hollow portion inside the molded product. It is being appreciated.

The structure of a conventional resin molding die apparatus by high hollow molding will be described below with reference to FIG.

As shown in the figure, the fixed side mold plate 2 is attached to the mounting plate 1.
Is fixed, and the mold is composed of a fixed side mold plate 2 and a movable side mold plate 3. A sprue bush 5 having a sprue 7 is fitted in the stationary mold plate 2, and the sprue 7 is used to inject resin into the mold and to supply high-pressure gas 8
It becomes the filling injection port. Reference numeral 9 is a molding machine nozzle for injecting resin into the mold through the sprue 7 and filling the high-pressure gas 8.

On the other hand, the movable mold plate 3 is provided with a movable insert 4 which constitutes a part of the mold plate.
After injecting the high-pressure gas 8, it moves backward to form a hollow portion inside the molded product 6.

Next, a conventional molding method using the above mold device will be described. First, the fixed side mold plate 2, the movable side mold plate 3, and the movable insert 4 form a mold. Next, molten resin is injected into the mold from the molding machine nozzle 9 through the sprue 7. After the resin is injected, the high pressure gas 8 is filled from the molding machine nozzle 9 in the direction of arrow B through the sprue 7 as shown in FIG. Next, move the movable insert 4 to the arrow A in FIG.
Direction is retracted to a predetermined position to form a hollow portion inside the molded product 6, and the molded product 6 is cooled while the pressure of the high pressure gas 8 is maintained.

Thereafter, as shown in FIG. 6 (b), the molding machine nozzle 9 is retracted from the sprue 7 to release the high-pressure gas 8 into the atmosphere as indicated by the arrow C, and then the movable side mold plate 3 and the movable inlet 3 are moved. After moving the child 4 backward and further moving the movable insert 4 forward to separate the molded product 6 from the movable side mold plate 3, the molded product 6 is taken out.

[0008]

In the conventional molding method described above, the sprue 7 also serves as a path for filling and discharging the high-pressure gas 8 inside the molded product 6, so that when the high-pressure gas 8 is discharged into the atmosphere. Only gas was released from sprue 7. Therefore, in the case of a molded product having a large hollow portion, it takes a long time to release the gas. Further, when the high-pressure gas 8 is discharged from the sprue 7, the semi-molten resin is deformed by the gas pressure at the time of discharge as shown in FIG. 7, and the gas discharge path inside the sprue 7 becomes smaller, so that the gas discharge from the sprue becomes smaller. There was a problem that was blocked.

The present invention solves the above problems, and provides a molding method and a mold apparatus for shortening the time for releasing high-pressure gas inside a molded product and for improving the productivity of a resin molded product due to the time reduction. To do.

[0010]

In order to achieve the above object, the present invention, in the conventional molding method, releases high-pressure gas inside the molded article from the sprue to the atmosphere at the same time as or before or after this step. The high-pressure gas inside the molded product is released into the atmosphere by using the gas release means provided on the movable insert or the stationary mold plate.

[0011]

With the above-described structure of the present invention, in addition to the high pressure gas discharge from the inside of the molded product from the conventional sprue, it is possible to newly discharge the high pressure gas from the movable insert or the fixed side mold plate, and the high pressure gas discharge time can be reduced. It can be shortened.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is an enlarged sectional view of a movable insert 4 portion of a resin molding die apparatus according to this embodiment.

As shown in the figure, inside the movable insert 4, there are arranged a gas discharge pin 10, a composite air cylinder 12 for penetrating the gas discharge pin 10 into the molded product 6, and a connecting rod 11 for connecting them. The gas release pin 10,
The compound air cylinder 12 and the connecting rod 11 constitute gas releasing means.

The resin molding method using the mold apparatus of FIG. 1 will be described below. The molding method of the present invention is the same as the conventional method except for the step of discharging the high-pressure gas 8 inside the molded product 6 to the atmosphere, and therefore the description of those steps will be omitted.

In this embodiment, the sprue 7 to the high pressure gas 8 are used.
At the same time as or before or after the gas is released into the atmosphere, the gas release pin 10 is moved upward by driving the composite air cylinder 12 as shown in FIG.
The high-pressure gas 8 inside the molded product 6 is discharged into the atmosphere from the gas vent hole 15 provided inside the pin through the path indicated by the arrow.

Table 1 shows the high-pressure gas release time according to the conventional method, and the high-pressure gas release timing from the sprue 7 and the high-pressure gas release timing from the gas release pin 10 at the same time. For comparison, it can be seen that the gas release time by the method of the present invention is significantly shortened as compared with the conventional one.

[0018]

[Table 1]

As described above, according to the molding method of the present invention, when the high pressure gas 8 is released, the gas is released from both the sprue 7 and the gas vent hole 15 of the gas release pin 10, thereby significantly increasing the gas release time. Can be shortened.

(Embodiment 2) In the embodiment shown in FIG. 3, the tip of the gas discharge pin 13 is made pointy, and in Embodiment 1 the gas discharge pin 10 is raised by driving the composite air cylinder 12. While the upper part of the pin penetrates into the molded product 6, the rotatable composite air cylinder 12 is used to raise the gas release pin 13 while rotating to penetrate the upper part of the pin into the molded product 6 and to the inside of the pin. The high pressure gas 8 inside the molded product is discharged into the atmosphere through the arranged gas vent hole 16.

Using the gas discharge pin 13 of this embodiment,
The gas release time can be shortened, the penetrating surface of the molded product 6 is clean, the quality of the product can be improved, and the penetration becomes easy.

(Embodiment 3) In the present embodiment shown in FIG. 4, unlike the gas release pins 10 and 13 provided with the gas vent holes 15 and 16 in Embodiments 1 and 2, unlike the high pressure gas 8 release, the gas release pin is shown. Internal gas is discharged from the penetration hole provided by the penetration of 14. Next, the operation will be described.

First, the gas discharge pin 14 is raised to penetrate into the molded product 6 (FIG. 4 (a)). After sufficiently penetrating the gas release pin 14 (Fig. 4 (b)), the gas release pin 14 is lowered to pull out the gas release pin 14 from the inside of the molded product 6, and molding is performed from the hole (penetration hole) through the path indicated by the arrow. The high-pressure gas 8 inside the product 6 is released into the atmosphere (FIG. 4 (c)).

When the gas discharge pin 14 of this embodiment is used, the gas path becomes large, and the gas discharge time is shorter than in the first and second embodiments. Further, it is not necessary to provide a gas vent hole inside the pin, which simplifies the device configuration.

Although the gas discharging means is provided in the movable insert 4 in each of the above-described embodiments, the gas discharging means may be provided in the stationary mold plate 2. When the gas releasing means is provided on the stationary mold plate 2, there is an advantage that a pipe for sending air to the composite air cylinder 12 can be easily attached, as compared with the case where the gas releasing means is provided on the movable insert 4. In this case, a penetration hole for the gas discharge pin is formed in a part of the appearance of the molded product 6, but depending on the molded product, there may be no problem even if the penetration hole exists.
Further, by using the gas discharge pin 13 of the second embodiment, it is possible to form a penetration hole having a clean appearance.

Further, in each of the above embodiments, the gas discharge pins 10, 13 and 14 were penetrated by driving the composite air cylinder, but it goes without saying that other driving equipment such as a hydraulic cylinder or a motor may be used. .

Further, by changing the shape and the number of the gas discharge pins, it is possible to discharge the gas in a shorter time.

[0028]

As described above, according to the present invention, the gas discharging means for discharging the high pressure gas inside the molded product is provided on the movable insert or the fixed side mold plate, and when the internal gas is discharged, the gas from the sprue is discharged. Since the gas can be released from the movable insert or the stationary mold plate together with the release, the gas release time can be shortened and the productivity of the resin molded product can be improved.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a mold device according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of the mold device according to the first embodiment showing a state in which the gas discharge pin penetrates the molded product.

FIG. 3 is an enlarged cross-sectional view showing the shape of a gas discharge pin of Example 2.

FIG. 4 is an enlarged cross-sectional view showing a gas releasing process by the gas releasing pin of the third embodiment.

FIG. 5 is a configuration diagram of a conventional resin molding die device.

FIG. 6 is an enlarged sectional view showing gas release from a sprue in a conventional mold device.

FIG. 7 is an enlarged cross-sectional view showing a problem in releasing gas from a sprue in a conventional mold device.

[Explanation of symbols]

 1 Mounting Plate 2 Fixed Side Mold Plate 3 Movable Side Mold Plate 4 Movable Insert 5 Sprue Bushing 6 Molded Product 7 Sprue 8 High Pressure Gas 9 Molding Machine Nozzle 10, 13, 14 Gas Release Pin 11 Connecting Rod 12 Composite Air Cylinder 15, 16 Vent hole

Claims (5)

[Claims] 1. A first step of injecting a resin from a molding machine nozzle through a sprue into a mold formed by a fixed side mold plate, a movable side mold plate and a movable insert, and from the molding machine nozzle through the sprue. A second step of filling the inside of the molded product with high-pressure gas, a third step of retracting the movable insert to a predetermined position to form a hollow portion inside the molded product, and a state of maintaining the pressure of the high-pressure gas A fourth step of cooling the molded product by means of the above, a fifth step of retracting the molding machine nozzle from the sprue, and discharging the high-pressure gas inside the molded product into the atmosphere, the movable side mold plate and the movable insert. In a resin molding method comprising a sixth step of retracting and taking out a molded product, at the same time as the fifth step or before or after the fifth step, a gas releasing means provided in the movable insert or the fixed side template is used. High-pressure gas inside the molded product Resin molding method, characterized in that to release into the atmosphere. 2. A fixed-side mold plate fixed to a mounting plate, a movable-side mold plate that is movable to compose a mold with the fixed-side mold plate; Sprue bushing having a sprue which is an injection port for resin injection and high-pressure gas filling, a molding machine nozzle for injecting a resin molding material into the mold through the sprue and high-pressure gas filling, and the movable side In a resin molding die device comprising a movable insert which constitutes a part of a mold plate, moves backward after gas injection, and forms a hollow portion inside a molded product, wherein the movable insert or the fixed-side mold plate is A resin molding die device comprising a gas discharge means for discharging high-pressure gas inside a molded product to the atmosphere. 3. The gas releasing means is a gas releasing pin for penetrating into the molded product and releasing high-pressure gas inside the molded product into the atmosphere through a gas vent hole, and a composite for raising the gas releasing pin to penetrate into the molded product. The resin molding die device according to claim 2, comprising an air cylinder and a connecting rod that connects the gas discharge pin and the composite air cylinder. 4. The gas releasing means includes a gas releasing pin which has a pointed tip and which penetrates into the molded product while rotating and releases the high pressure gas inside the molded product into the atmosphere through a gas vent hole, and the gas releasing pin. The resin molding die device according to claim 2, comprising a composite air cylinder that is raised while rotating and penetrates into a molded product, and a connecting rod that connects the gas discharge pin and the composite air cylinder. 5. The gas releasing means, after penetrating into the molded article,
A gas ejection pin that retreats to provide a gas emission penetration hole in the molded product, through which the high pressure gas inside the molded product is released to the atmosphere, and a compound air cylinder that raises the gas emission pin and penetrates into the molded product And a connecting rod that connects the gas discharge pin and the composite air cylinder.