JPH03222713A - Molding tool for manufacture of hollow molding - Google Patents

Abstract

PURPOSE:To make arrangement of a fluid casting route easy, by a method wherein a fluid casting route casting a fluid for hollow part molding into resin within a cavity is provided within a pushing-up pin extruding a molding outside, which is integrated and the diameter of a fluid casting port is made into a range of a specific diameter. CONSTITUTION:For example, two pushing-up pins 1 are provided by penetrating through the inside of a movable mold 93, the inside of which is made into a fluid casting route 10 in a state of a hollow and the top of a tip part 11 is arranged so that the same becomes flush with a mold surface 935 of the movable mold 93. A fluid casting port 101 is opened into the tip part 11 and the diameter of the port 101 is made into 0.02-0.2mm. A base end part 12 of the pushing-up pin 1 is connected with a pressurized nitrogen gas source and a pushing-up plate 94 is connected with the vicinity of the base end part 12. At a point of time when resin is injected within a cavity 90 and the resin is positioned more outside than the fluid casting port 101, a hollow molding is manufactured by casting the nitrogen gas 85 through the fluid casting port 101. When the diameter of the fluid casting port 101 exceeds 0.2mm, it is feared that the resin injected within the cavity enters into the fluid casting route through the fluid casting port.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a mold for producing a blow molded product, and particularly to the configuration of a fluid injection path thereof.

[Prior art]

Hollow molded synthetic resin products are manufactured by injecting softened synthetic resin into the cavity of a mold and injecting a fluid such as nitrogen gas or water into the synthetic resin to make the inside hollow. do.

Conventionally, as a mold used for manufacturing such a hollow molded product, a fixed mold 9 disposed on a fixed plate 91 is used as shown in FIG.
2, a movable mold 93 provided on a movable plate 931, and a cavity 9o formed between the two.

It consists of a sprue 920 for injecting the softened synthetic resin 81 into the cavity 90 and a fluid injection path 86 for injecting the fluid 85 into the softened synthetic resin 81 in the cavity 90 (see Publication No. 58-211425).

Further, a push-up pin 95 is inserted and disposed in the movable mold 93 for pushing out the formed hollow molded product to the outside of the mold. In addition, a guide rod 9 vertically installed on the fixed plate 91
The lower part of the movable plate 931 is inserted into the side part of the movable plate 931.

Further, a push-up plate 94 is provided below the push-up pin 95.
Concatenate. The push-up plate 94 is connected to an actuator (path shown) that moves it up and down. The fluid injection path 86 is constituted by a vibrator inserted through the movable mold 93 and the movable plate 931. Further, the sprue 920 of the fixed type 92 has an injection nozzle 71 provided on the fixed plate 91.
Concatenate.

Further, a large number of cooling pipes 97 are provided in the fixed mold 92 and the movable mold 93, respectively, facing the cavity 90.

In manufacturing the hollow molded product, a softened synthetic resin 81 is injected into the cavity 90 from the injection nozzle 71, as shown in FIG.

The injection amount of this synthetic resin is the volume obtained by subtracting the hollow part (i.e., the fluid injection amount) from the cavity volume (i.e., the volume of the hollow molded product). Immediately after the injection, a fluid 85 such as nitrogen gas is injected through the fluid injection path 85.

As a result, the softened synthetic resin 8 inside the cavity 90
1 is pressed against the cavity wall surface and the cavity space portion by the fluid 85 injected into the interior thereof. After the cavity 90 is filled with the first synthetic resin 81 and the fluid 85 therein, water is flowed through the cooling pipe 97 to cool and solidify the first synthetic resin 81.

After that, the movable mold 93 and the movable plate 931 are
It is lowered by a movable advance/retreat actuator rod 76 via a frame 75 provided at 31. As a result, the fixed mold 92 and the movable mold 93 are separated, and the cavity 90 is opened. Then, the push-up pin 95 is pushed up by the push-up plate 94, and the hollow molded product inside the cavity is taken out.

[Problem to be solved]

However, in the above-mentioned conventional mold, the fixed mold 92
．． In addition to providing the cooling pipe 97, the movable mold 93 must also be provided with a hydraulic pipe for access and the above-mentioned push-up pin 95.

Furthermore, the one-car mold must have a mold surface for forming the cavity 90, but in recent years, the mold surface has become complicated because the shape of the hollow molded product is complicated. Moreover, both types
Around it, as shown in FIG. 3, there is a guide rod 96.
Accessory parts such as the actuator door 6 are provided.

Therefore, it is difficult to arrange the @body injection route.

Furthermore, it is difficult to design a mold.

In view of these conventional problems, the present invention seeks to provide a mold for producing a hollow molded product in which the arrangement of a fluid injection path and the design of the entire mold are easy.

[Means for solving problems]

The present invention has two components: a cavity for molding a synthetic resin hollow molded product; a sprue for injecting the softened synthetic resin into the cavity; and a fluid for molding the hollow part in the softened synthetic resin in the cavity. In a mold for producing a hollow molded product, the mold has a fluid injection path for injecting fluid and a push-up pin for pushing the formed hollow molded product out of the mold. The tip of the push-up pin has a diameter of 0.02 to 0.0 mm on the surface facing the cavity. 2
The mold for producing a hollow molded product is characterized in that it has a fluid inlet of wn, and that the base end of the push-up pin is connected to a fluid pipe.

What is most noteworthy about the present invention is that the fluid injection path is provided within the push-up pin to integrate the two, and that the fluid injection port at the tip of the push-up pin has a diameter within the above-described specific diameter range.

As described above, the push-up pin is for pushing out the manufactured hollow molded product from the cavity, and also serves as the fluid injection path.

Further, the fluid inlet has a diameter of 0.02 to 0.2 mm. If it is less than 0.02n++++, a sufficient volumetric velocity of the fluid injected into the softened synthetic resin cannot be obtained. Therefore, before the softened synthetic resin and fluid such as gas therein fills the cavity.

There is a risk that the softened synthetic resin tip may cool and solidify, making it impossible to obtain the desired hollow molded product. Also.

The production speed of blow molded products will decrease.

On the other hand, if it exceeds 0.2 mm, the softened synthetic resin injected into the cavity will be exposed to the high pressure (400 to 500
kg/cla), there is a risk that the liquid may enter the fluid injection path from the fluid injection port of the push-up bottle.

The shape of the fluid inlet may be arbitrary, such as bicircular, elliptical, or square. Further, the above-mentioned diameter refers to the length of the longest diameter bone.

Further, as described above, although the fluid injection path is provided integrally with the push-up pin, one or more push-up bottles are provided. If multiple locations are provided, fluid is injected from each location. In addition, it goes without saying that a push-up pin without a fluid injection path similar to the conventional one can be provided together with the push-up pin within the fluid injection path according to the present invention.

Further, the tip of the push-up bottle is flush with the inner wall of the cavity (FIG. 1), or is slightly protruded (FIG. 3).

Further, in the fluid injection path, a check valve may be provided at the base end portion of the push-up bottle or a fluid pipe connected to the push-up bottle. Thereby, it is possible to reliably prevent the softened synthetic resin from flowing back into the fluid injection path.

[For production]

In the present invention, after injecting the softened synthetic resin into the cavity, from the fluid injection port at the tip of the push-up pin,
A fluid such as gas or water is injected into the softened synthetic resin.

5. A blow molded product is manufactured in the same manner as before. Also, after manufacturing hollow molded products.

Open the cavity, push up the push-up pin, and push out the hollow molded product inside the cavity.

In one aspect of the present invention, the fluid injection path is provided within the push-up bottle, so there is no need to separately provide a fluid injection path that penetrates inside the fixed movable mold, etc., as in the prior art. Moreover, this allows more space for the mold. Furthermore, since the fluid injection path and the push-up pin are integrated, the structure of the mold becomes simpler.

Further, in the present invention, since the fluid injection port has the above-described specific diameter, the softened synthetic resin does not enter the fluid injection path in the push-up pin, and the softened synthetic resin does not enter the softened synthetic resin at an appropriate speed. Fluid can be injected.

[Effects] Therefore, according to the two aspects of the present invention, it is possible to provide a mold for producing a hollow molded product in which the arrangement of the fluid injection path and the design of the entire mold are easy.

[Example] First Example This is an example of the present invention. A mold for producing a hollow molded product will be explained using FIGS. 1 and 2.

The mold of this example is provided with two push-up pins 1 that penetrate inside the movable mold 93. The push-up pin 1 has a hollow fluid injection path 10 therein. The upper surface of the tip portion 11 of the push-up bottle 1 is arranged so as to be flush with the mold surface 935 of the movable mold 93 when the mold is closed. The distal end 11 also includes an ia body injection route 1.
0 fluid inlet 101 is open. The fluid inlet 1
゜1 is a circular frontage part with a diameter of 0.1 gloss. Also.

The diameter of the fluid injection path is 1 m.

On the other hand, a fluid vibrator 15 connected to a pressurized nitrogen gas source is connected to the base end 12 of the third push-up pin l.

The fluid vibrator 15 is a flexible hose that can follow the vertical movement of the push-up pin 1. Further, a push-up plate 94 similar to the conventional push-up plate 94 is connected to the vicinity of the base end portion 12 of the push-up bottle 1. The rest is the same as the conventional example (FIG. 4).

In manufacturing a hollow molded product using the mold of this example, a softened synthetic resin (path shown) is injected into the cavity 90 in the same manner as in the prior art. When the softened synthetic resin is located outside the fluid injection port 101, a fluid 85 using nitrogen gas is injected from the fluid injection port 101 through the fluid injection path 10 in the push-up bottle 1. Then, a blow molded product is manufactured in the same manner as before.

After molding, the movable mold 93 is lowered to open the cavity 90, and the push-up plate 94 is then raised to release the push-up pin 1.
push up. As a result, the hollow molded product inside the cavity is taken out.

As described above, according to the mold of this example, the fluid injection path is provided within the push-up pin, so there is no need to separately provide a fluid injection path that penetrates inside the fixed mold, movable mold, etc. Moreover, the space for the molding die is freed, and the structure is simple.

Further, since the fluid injection port has a small diameter as described above, the softened synthetic resin does not enter the push-up pin, and the fluid can be injected at an appropriate speed.

Second Embodiment In this embodiment, as shown in FIG. 3, the tip portion 11 of the push-up pin 1 is arranged in the mold of the first embodiment so as to slightly protrude into the cavity 90. The rest is the same as the first embodiment.

In this example as well, the same effects as in the first example can be obtained.

[Brief explanation of drawings]

1 and 2 show the mold of the first embodiment, FIG. 1 is a sectional view thereof, FIG. 2 is a plan view of the main part of the mold surface of the movable mold, and FIG.
The figure is a cross-sectional view of a main part of the mold of the second embodiment, and the fourth figure is a cross-sectional view of a conventional mold. 1. 10. 101°11. 12. 90,. 92,. 93,. Push up pin. Fluid injection path. , fluid inlet. tip. Proximal end. Fixed cavity type. Movable type. Applicant Toyoda Gosei Co., Ltd. Agent

Claims (1)

[Claims] A cavity for molding a synthetic resin hollow molded product,
A sprue for injecting the softened synthetic resin into the cavity, a fluid injection path for injecting a fluid for molding the hollow part into the softened synthetic resin in the cavity, and a molded hollow molded product. In a mold for manufacturing a hollow molded product having a push-up pin for pushing out the mold, the fluid injection path is provided by making the inside of the push-up pin hollow, and the tip of the push-up pin is connected to the cavity. A mold for producing a hollow molded product, characterized in that it has a fluid inlet with a diameter of 0.02 to 0.21 on the opposing surface, and the base end of the push-up pin is connected to a fluid pipe.