JPH04189523A - Manufacture of resin molded product - Google Patents

Abstract

PURPOSE:To improve the manufacturing efficiency, by a method wherein after injection molding of resin by making use of a core made of the resin in which flexible main insert exposed from an end face of the core having a hollow part and a plurality of flexible auxiliary inserts which are caused to branch from the same are buried, an exposed end part of the main insert is pulled and the core is collapsed. CONSTITUTION:A core 1 made of resin, which is molded under a state where at least one flexible insert member 4 which is extended in a fixed direction in parallel with the surface of the core 1 and has at least one end part exposing outside from an end face of the core 1 and a plurality of flexible auxiliary insert members 5 which is caused to branch from the flexible main insert member 4 are buried is used. When exposing both end parts of the flexible main insert member 4 are pulled in the direction indicated by arrow A, though the core 1 is destroyed at a V-shaped groove 8, since a U--shaped groove 7 is formed along the member 4 on the inside of the core 1, the core 1 is not destroyed at a part in which the member 4 is buried and every part including the insert members 4, 5 is removed from a resin molded product 12. Therefore, manufacturing efficiency of the molded product 12 can be improved.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a method for manufacturing resin molded products.
More specifically, it has a hollow part! This invention relates to a method of manufacturing finger molded products by injection molding.

Prior Art When a resin molded product with a hollow part is manufactured by injection molding, a core with a lower melting point than the resin molded product is used to form the hollow part, and after molding, it is immersed in heated oil,
Alternatively, the core was heated with a heater to disintegrate the core and remove it (for example,
No. 6813 etc. ).

Conventionally, such cores have been made of bismuth, which has a low melting point.
Cores made of alloys such as tin eutectic alloys have been used, but cores made of alloys such as bismuth-tin eutectic alloys generally have a high specific gravity and are difficult to handle. There was a problem in that it took time to disintegrate and remove the core.

Therefore, in recent years, cores made of water-dispersible plastics have been used. ), a resin molded product with a hollow part is injection molded,
A method has been proposed in which the core is removed by soaking it in warm water after it has been boiled.

Problems to be Solved by the Invention As described above, when a resin molded product is molded using a water-dispersible plastic core and then the core is removed by soaking it in hot water, handling is easy. However, it takes time to disintegrate and remove the core, reducing manufacturing efficiency, and the heat applied during injection molding melts a portion of the surface of the core, resulting in a resin molded product. There was a problem in that the inner surface of the resin became rough, making it impossible to obtain high-quality resin molded products.

OBJECTS OF THE INVENTION The first object of the present invention is to provide a method for manufacturing a resin molded product having a hollow portion using a core, which can significantly improve manufacturing efficiency. There is a particular thing.

A second object of the present invention is to provide a method for manufacturing resin molded products that can significantly improve manufacturing efficiency and produce high-quality resin molded products. It is.

Structure of the Invention The first object of the present invention is to provide a core having a hollow part,
at least one flexible main insert member extending in a predetermined direction substantially parallel to the surface of the core and having at least one end thereof exposed to the outside from the end surface of the core; A molded resin core in which a plurality of flexible sub-insert members branched from the insert member are embedded is set in a mold, resin is injection molded, and after molding the resin molded product, the above-mentioned The present invention is characterized in that the core is collapsed and removed from the resin molded product by pulling the one end portion of at least one flexible main insert member that is exposed to the outside from the end surface of the core. This is achieved by one invention.

The first object of the present invention further provides that the at least one
A substantially U-shaped groove is formed on the inner surface along the two flexible main insert members, and on both sides of the substantially U-shaped groove,
The core is characterized in that the core is formed such that a pair of substantially V-shaped grooves are formed at a position farther from the substantially U-shaped groove than the end of the flexible sub-insert member. This case number 2
Achieved by invention.

According to a second object j of the present invention, the at least one flexible main insert member and the plurality of flexible sub-insert members are formed of a material having higher thermal conductivity than the core, and Achieved by the third invention, characterized in that the core is set in the mold such that at least one end of at least one flexible main insert member is in contact with the mold. .

Effect of the Invention According to the first invention, the core includes at least one movable member extending in a predetermined direction substantially parallel to the surface of the core, and at least one end thereof is exposed to the outside from the end surface of the core. Since resin molded cores are commonly used in which a flexible main insert member and a plurality of flexible sub-insert members branched from the flexible main insert member are embedded, it is difficult to make resin molded products. After molding, by pulling one end exposed to the outside from the end face of the core of at least one flexible main insert member, the core collapses, making it possible to easily remove the resin molded product. This makes it possible to significantly improve manufacturing efficiency.

According to the second invention, a substantially U-shaped groove is further formed on the inner surface along the at least one flexible main insert member, and at least one flexible groove is formed on both sides of the oval-shaped groove. The core is formed such that a pair of substantially V-shaped grooves are formed at a position farther from the substantially U-shaped groove than the end of the flexible insert member branching from the flexible main insert member. Therefore, after molding the resin molded product, at least 1
When one end exposed to the outside is pulled from the end face of the core of two flexible main insert members, the core breaks at the pair of approximately V-shaped grooves, but at least one of the Since the substantially U-shaped groove is formed along the flexible main insert member, the core will not break in the area where at least one flexible main insert member is disposed.
Therefore, the core can be easily removed from the resin molded product, and manufacturing efficiency can be greatly improved.

According to the third invention, at least one flexible main insert member and a plurality of flexible insert members are formed of a material having higher thermal conductivity than the core, and
At least one flexible main inserter) The core is set in the mold so that at least one end of the material is in contact with the mold, and the resin is molded, so the heat inside the core is is transmitted to the mold from at least one flexible main insert member or from a plurality of flexible insert members branching from the at least one flexible main insert member, and the mold As a result, the core is cooled, which prevents the surface of the sheath that is in contact with the resin from melting during resin injection molding. Similar to the second invention, the core can be easily removed from the resin molded product, making it possible to greatly improve manufacturing efficiency and producing high-quality resin molded products! ! ! It becomes possible to build.

Embodiments Hereinafter, embodiments of the present invention will be explained in detail based on the accompanying drawings.

FIG. 1 is a longitudinal sectional view approximately at the center of a core used in a method for manufacturing a resin molded product according to an embodiment of the present invention.

In FIG. 1, a core 1 is formed by welding a pair of substantially semicylindrical shells 2a and 2b made of water-dispersible plastic, and has a hollow B3.

FIG. 2 shows a flexible main insert member 4 made of a metal wire embedded in the core 1 during molding of the core 1, and a plurality of flexible insert members 5 made of metal wires branching from the main insert member 4.
It is a schematic perspective view of an insert member unit 6 consisting of
FIG. 3 is a schematic partial cross-sectional view of the core 1 taken at right angles to the longitudinal direction of the flexible main insert member 4. FIG.

The flexible main insert member 4 shown in FIG. 2 and the plurality of flexible insert members 5 branching from it at approximately right angles are both embedded in the core 1 approximately parallel to the surface of the core 1. An insert member unit 6 is formed by one flexible main insert member 4 and a plurality of flexible main insert members 5 branching from the main insert member 4, and as shown in FIG. A unit 6 is embedded within the core 1. Further, as shown in FIG. 3, a substantially U-shaped groove 7 is formed on the inner surface of the core along the aesthetic main insert member 4, and a substantially U-shaped groove 7 is formed on the inner surface of the core. A substantially V-shaped groove 8 is formed on the inner surface of the core 1 on both sides and further away from the substantially U-shaped groove 7 from the end of the flexible insert member 5 .

FIG. 4 shows that the core 1 is set in the mold 9 and the resin is ejected a.
FIG. 2 is a schematic partial cross-sectional view of the contact portion between the core 1 and the mold 9 during molding. As shown in FIG. 4, both ends of the aesthetic main insert member 4 embedded in the core 1 are exposed to the outside from the core 1. A groove 10 is formed to accommodate the exposed ends of the main insert member 4. Both exposed ends of the flexible main insert member 4 are in contact with the mold 91, and the flexible main insert member 4 and the plurality of flexible sub-insert members 5 are each formed of metal wire. Because of this, its thermal conductivity is higher than that of the water-dispersible plastic that forms the core 1. Therefore, the heat inside the core 1 during injection molding is transferred from the flexible main insert member 4 to the mold 9. Conveyed with multiple flexible secondary inserts.

The material 5 is transmitted to the mold 9 via the flexible main insert member 4 and released from the mold 9, and as a result, the core 1 is cooled. resin 1
1 is prevented from melting and causing roughness on the surface of the resin molded product on the core 1 side.

FIG. 5 is an explanatory diagram showing a step of removing the core 1 from the resin molded product 12 after the resin molded product 12 is molded. As shown in FIG. 5, when both ends of the core 1 of the flexible main insert member 4 exposed to the outside are pulled in the direction of the arrow, the core 1 becomes approximately V-shaped. However, since a substantially U-shaped groove 7 is formed on the inner surface of the core 1 along the flexible main insert member 4, the flexible main insert member 4 In the part where is embedded, core 1 is
Therefore, the core 1 is removed from the resin molded product 12 in parts containing one insert member unit 6, as shown in FIG. In this way, by pulling both ends exposed to the outside of the core 1 of the flexible main insert member 4 of the insert member unit 6 one after another in the direction of arrow A, the core can be easily removed. It becomes possible to remove the child 1 from the resin molded product 12.

According to this embodiment, after injection molding of the resin molded product, the flexible main insert member 4 of the insert member unit 6 is
By pulling both ends exposed to the outside of the core 1 one after another, the core 1 can be easily and quickly removed from the resin molded product 12. In addition, the aesthetic main insert member 4 and the plurality of flexible sub-insert members 5 branching from the main insert member 4 are each made of a metal wire. The outer ends of the flexible main insert member 4, which are exposed to the outside of the core 1, have higher thermal conductivity than the water-dispersible plastic forming the core 1. Since the core 1 is accommodated in the groove 10 of the core 1 and is in contact with the mold 9, the heat within the core 1 is transmitted to the mold 9 via the flexible main insert member 4 during injection molding. As a result, the core 1 is sufficiently cooled, so that the resin 1 of the core 1 is released from the mold 9.
1 can be reliably prevented from being melted, and therefore a high quality resin molded product 12 can be obtained without causing rough skin.

The present invention is not limited to the above-mentioned examples, and various modifications can be made within the scope of the invention described in the claims, and these are also included within the scope of the present invention. It goes without saying that there is.

For example, in the embodiment described above, a plurality of insert member units 6 are disposed within the core 1, but depending on the size of the core 1, a plurality of insert member units 6 may be disposed within the core 1. At least one insert member unit 6 may be provided within the core 1.

Further, in the embodiment described above, the flexible main insert R material 4 is arranged so that both ends of the flexible main insert member 4 are exposed to the outside of the core 1. Both ends do not need to be exposed; at least one end
It is sufficient that the flexible main insert member 4 is disposed so as to be exposed to the outside of the core 1.

Furthermore, in the embodiment described above, the flexible main insert member 4 is arranged such that both ends of the flexible main insert member 4 are attached to the outside of the core 1, and both ends are in contact with the mold 9. The insert member 4 is disposed, and the core 1 is set in the mold 9, and the flexible main insert member 4 is disposed so that at least one end abuts against the mold 9. , the core 1 is set in the mold 9 (',), and if the resin molded product 12 is not prone to rough skin, or by other cooling means, the core 1 may be set in the mold 9. If cooling is possible: =
In this case, the flexible main insert member 4 and the mold 9 do not need to be in contact with each other.

In addition, in the above embodiment, a substantially U-shaped groove 7 and a substantially V-shaped groove 8 are formed on the inner surface of the core 1, but these are not necessarily essential. , especially when the wall thickness of the core 1 is small, it is not necessary to provide it.

Furthermore, during injection molding, the core 1 may be cooled using cooling air.

Further, in the above embodiment, the core 1 having a cylindrical outer shape is used, but the outer shape of the core 1 is determined by the shape of the hollow part of the resin molded product to be injection molded, and the outer shape of the core 1 is determined by the shape of the hollow part of the resin molded product to be injection molded. Needless to say, it is not limited.

Further, in the embodiment, the core 1 is the shell 2a,
Although the core 2b is molded by welding, it is also possible to integrally mold the core 1 of a desired shape1,)C Effects of the Invention According to the first invention and the second invention i2, Use the core'7
), the method for manufacturing resin molded products with hollow parts □
This makes it possible to significantly improve manufacturing efficiency.
Further, according to the third invention, in the method of manufacturing a resin molded product having a hollow part using a core, it is possible to significantly improve manufacturing efficiency, and to produce high-quality resin. It becomes possible to provide a method for manufacturing a resin molded article that can manufacture a molded article.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view approximately at the center of a core used in a method for manufacturing a resin molded product according to an embodiment of the present invention. FIG. 2 is a schematic perspective view of an insert member unit consisting of a flexible main insert member embedded in a core and a plurality of flexible sub-insert members branching from the main insert member;
The figure is a schematic cross-sectional view of the core taken at right angles to the longitudinal direction of the flexible main insert member. FIG. 4 is a schematic thin sectional view of the contact portion between the core and the mold in a state where the core is set in the mold and injection molding of resin is being performed. Figure 5 shows how the core is removed after molding the resin molded product.
! It is an explanatory view showing a process of removing from a finger molded product. DESCRIPTION OF SYMBOLS 1... Core, 2a, 2b... Nenobe 3... Hollow part, 4... Flexible main insert member, 5... Flexible sub-insert member, 6... Insert member unit , 7... Approximately U-shaped groove, End... Approximately V-shaped groove, 9... Mold, 10... Mold groove, 11... Resin, 12... Resin molding Goods. Figure 1 Figure 2

Claims (3)

[Claims] (1) A core having a hollow portion, which extends in a predetermined direction approximately parallel to the surface of the core, and at least one end thereof is exposed to the outside from the end surface of the core. A molded resin core in which a flexible main insert member and a plurality of flexible sub-insert members branched from the flexible main insert member are embedded is set in a mold, and the resin is inserted into the mold. injection molding, and after molding the resin molded product, collapsing the core by pulling the one end portion of the at least one flexible main insert member that is exposed to the outside from the end surface of the core; A method for manufacturing a resin molded product, which comprises removing the resin molded product from the resin molded product. (2) Further, a substantially U-shaped groove is formed on the inner surface along the at least one flexible main insert member, and the flexible secondary insert member is formed on both sides of the substantially U-shaped groove. Claim (1) characterized in that the core is molded so that a pair of substantially V-shaped grooves are formed at a position farther from the substantially U-shaped groove than the end of the member. A method for manufacturing the resin molded product described above. (3) The at least one flexible main insert member and the plurality of flexible sub-insert members are formed of a material having higher thermal conductivity than the core, and the at least one flexible main insert member The resin molded product according to claim 1 or 2, wherein the core is set in the mold so that at least one end of the insert member comes into contact with the mold. Production method.