JPH06182806A - Method and mold for hollow molded product - Google Patents

Abstract

PURPOSE:To enhance production efficiency by providing a first male mold and first and second female molds to one mold and providing a second male mold and third and fourth female molds to the other mold and performing molding by one female molds during the connection of the split elements of the other female molds. CONSTITUTION:A first male mold 41 and first and second female molds 51, 52 are provided to one mold 38 and a second male mold 42 and third and fourth female molds 53, 54 are provided to the other mold 39. The male mold 41 and the female molds 51, 52 are arranged at equal radius positions at an equal interval with respect to the center point 38a of the mating surface of the mold 38. The male mold 42 and the female molds 53, 54 are also arranged in the same way. The male molds 41, 42 are engaged with the female molds 53, 51 and a resin is injected to mold spilt elements 61, 62 and these elements are abutted. In this state, a resin is injected in the periphery of the abutted surface to bond both elements.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for molding a hollow molded article which can be easily molded by an injection molding method even if it is a hollow body made of a completely sealed body.

[0002]

2. Description of the Related Art A conventional method for molding a hollow molded article of this type is known from Japanese Patent Publication No. 2-38377. According to the method disclosed in the same publication, as shown in FIG. 13, one mold 3 is provided with a male mold 15 and a female mold 16 for molding divided bodies 31 and 32 obtained by dividing a hollow molded product into two parts, and the other mold is formed. A pair of metal molds 3 and 4 in which a female mold 17 and a male mold 18 which face the male mold 15 and the female mold 16 are provided in the mold 4 are used.

First, the male molds 1 of the molds 3 and 4 facing each other.
Molten resin is injected into a pair of cavities 19 and 20 formed between the molds 5 and 18 and the female dies 17 and 16 to mold the divided bodies 31 and 32.

Next, one of the molds 3 is slid upward so that the divided bodies 31, 32 left in the female molds 17, 16 are left.
To face each other. Then, as shown in FIG. 14, the molds 3 and 4 are matched with each other, and the divided bodies 31 and 32 are butted against each other. After that, a molten resin is injected to the peripheral edge of this abutting surface to weld each of the divided bodies 31 and 32 to each other, and then the mold is removed.

[0005]

In the above-mentioned conventional method, the male molds 15 and 18 are idle during the step of joining the divided bodies 31 and 32 to each other. That is, there is a problem that the step of molding the divided bodies and the step of joining the divided bodies are performed alternately, and the number of products produced per unit time is small. In addition, there is also a problem that molding having extremely different injection capacities must be alternately performed.

[0006]

A method for molding a hollow molded product according to the present invention uses a pair of molds having a male mold and a female mold for molding a divided body having a shape obtained by dividing the hollow molded product into two parts. The mating surfaces of the molds are made to face each other and are engaged with each other, the molten resin is injected to mold the two divided bodies, and then the divided bodies are abutted while being held by the respective molds. The present invention relates to an improvement in a method of molding a hollow molded article by changing the engagement posture and then injecting molten resin to the peripheral edges of the abutting surfaces of both divided bodies to join the divided bodies.

One mold is provided with a first male mold and a total of two female molds of the first and second molds. The other mold is provided with a second male mold and a total of two female molds of the third and fourth molds. In both molds, the male mold and the female mold are circumferentially spaced by 120 ° about one point on the mating surface of each mold and equidistant (that is, equidistant from the center). It is arranged.

First, the step of engaging the first male die with the third female die and the second male die with the first female die to form a divided body, and the second female die The step of connecting the divided body in the inside and the divided body in the fourth female mold is simultaneously performed.

Next, the step of engaging the first male die with the fourth female die and the second male die with the second female die to form the divided body, and the first female die The step of joining the divided body in the mold and the divided body in the third female mold is simultaneously performed.

The molding die of the hollow molded article of the present invention is a molding die for molding a resin molded article, and one of the pair of molds to be matched is used. Is provided with a first male mold and a total of two female molds of the first and second molds, and the other mold is provided with the second male mold, the third and fourth molds.
, A total of two female dies are provided, and in both dies, the male die and the female die are circumferentially spaced at 120 ° with one point on the mating surface of each die being the center, and the like. It is characterized by being arranged in a radial position.

[0011]

In the hollow molding product forming method and molding die of the present invention, each die is provided with two female dies, and the divided bodies in one female die are subjected to the joining step. In the meantime, the other female mold is used to mold the divided body. Therefore, the joining process of the divided bodies is continuously continued without interruption except for the product take-out time, and the number of products produced per unit time is almost double that of the conventional one.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic perspective view of molds 38, 39 according to an embodiment, one mold 38 having a first male mold 4
1, a first female die 51 and a second female die 52 are provided. The other mold 39 is provided with a second male mold 42, a third female mold 53, and a fourth female mold 54.

The male die 41 and the female dies 51, 52 are arranged at equal intervals of 120 ° in the circumferential direction and at equal radius positions with respect to the center point 38a of the mating surface of the die 38. Male 42, female 5
3, 54 are arranged at equal intervals of 120 ° in the circumferential direction and at equal radial positions with respect to the center point 39a of the mating surface of the mold 39. The distances from the center points 38a and 38b to the centers of the male and female dies are equal in the dies 38 and 39.

2 and 3 are schematic cross-sectional views showing the engaged state of the molds 38, 39. In FIG. 2, the male molds 41, 42 are engaged with the female molds 53, 51. , The resin is injected to form the divided bodies 61 and 62. The mold 38
Main switching gate 70 and hot runner nozzle 7
1, 72, 73 are provided. 74 is a nozzle of the injection machine.

In FIG. 3, the divided bodies 61 and 62 are butted, and resin is injected around the butted surfaces to join the divided bodies 61 and 62. 81 is a hot runner nozzle.

Next, the procedure for forming a hollow molded article will be described with reference to FIGS.

First, as shown in FIGS. 4 and 5, the molds 38 and 39 are matched with each other, and resin is injected to form the divided bodies 61 and 62. Next, the molds 38 and 39 are separated from each other (Fig. 6), and the mold 39 is rotated by 120 ° about its central axis (Seventh).
Figure). Then, as shown in FIG.
62 are butted and a resin is injected to the outer periphery thereof to join the divided bodies 61 and 62. In parallel with this, resin is injected between the male mold 42 and the female mold 52 and between the male mold 41 and the female mold 54 to mold new divided bodies 63 and 64.

Next, the mold is opened as shown in FIG.
A hollow molded product 65 composed of a combined body of 1, 62 is taken out.

Thereafter, the mold 39 is rotated by 120 ° (FIG. 10), and the molds 38 and 39 are matched. Then, as shown in FIG. 11, resin is injected to the outer periphery of the divided bodies 63 and 64 to join the divided bodies 63 and 64, and at the same time, new divided bodies 66 and 67 are molded.

Then, as shown in FIG. 12, the mold is opened, and the hollow molded product 68 formed by joining the divided bodies 63 and 64 is taken out.

After FIG. 12, the state shown in FIG. 7 is entered, and the steps of FIGS. 7 to 12 are repeated in this order. As a result, the molding of the divided bodies and the joining of the divided bodies are simultaneously performed, and hollow molded articles are continuously molded one after another.

In the present invention, any resin can be used as the resin, but polyethylene, polypropylene, polystyrene, polyvinyl chloride, ABS resin and the like are particularly preferable. Also, these recycled products can be used.

[0023]

As described above, according to the molding method and the molding die of the present invention, the molding of the divided body and the molding of the hollow molded article by the joining of the divided bodies are simultaneously carried out.
The production efficiency of the hollow molded product is significantly improved.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of molds 38 and 39 according to an embodiment.

FIG. 2 is a schematic cross-sectional view of molds 38 and 39.

FIG. 3 is a schematic cross-sectional view of molds 38 and 39.

FIG. 4 is a procedure explanatory diagram of a molding method.

FIG. 5 is a procedure explanatory diagram of a molding method.

FIG. 6 is an explanatory diagram of a procedure of a molding method.

FIG. 7 is a procedure explanatory diagram of a molding method.

FIG. 8 is an explanatory diagram of a procedure of a molding method.

FIG. 9 is a procedure explanatory diagram of a molding method.

FIG. 10 is an explanatory diagram of a procedure of a molding method.

FIG. 11 is a procedure explanatory diagram of a molding method.

FIG. 12 is an explanatory diagram of a procedure of a molding method.

FIG. 13 is a sectional view illustrating a conventional method.

FIG. 14 is a sectional view illustrating a conventional method.

[Explanation of symbols]

 38,39 Mold 41,42 Male 51,52,53,54 Female 61,62,63,64,66,67 Split body 65,68 Hollow molded product

Claims (2)

[Claims] 1. A method of molding a resin molded product using a pair of molds, wherein both molds are a male mold and a female mold for molding a divided body of a hollow molded product divided into two parts. Have their own mating surfaces, and the mating surfaces of both molds face each other and are engaged with each other, and molten resin is injected to form two divided bodies. After changing the engagement posture of the mold so that they are held in the mold, the molten resin is injected to the peripheral edge of the abutting surface of both divided bodies to join the divided bodies to form a hollow molded product. In the method, one mold has a first male mold and a total of two of the first and second molds.
One female die is provided, and the other die has a second male die and a third and a total of two die.
Each of the molds is provided with one female mold, and the male mold and the female mold are one of the mating surfaces of the respective molds.
The first male mold is engaged with the third female mold while the second male mold is engaged with the first female mold with 120 ° intervals in the circumferential direction around the point. To form the divided body and the step of connecting the divided body in the second female mold and the divided body in the fourth female mold at the same time, and then the first male mold To engage the fourth female mold and the second male mold to the second female mold to form the divided body, and the divided body in the first female mold and the third female mold. A method for molding a hollow molded article, characterized in that the step of bonding the divided bodies in the mold is performed at the same time. 2. A molding die for molding a resin molded product, comprising a pair of molds to be matched with each other, wherein one mold has a first male mold, First and second total 2
One female die is provided, and the other die has a second male die and a third and a total of two die.
Each of the molds is provided with one female mold, and the male mold and the female mold are one of the mating surfaces of the respective molds.
A molding die for a hollow molded article, wherein the molding dies are arranged at 120 ° intervals in the circumferential direction with respect to a point and at equal radius positions.