JP2002028956A - Method for injection-molding hollow molded article and mold apparatus for injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for injection molding in which there exists no possibility of slipping out of the position of a molded article and being elongated of the molded article by resistance to mold release when a melt molding raw material is filled into a cavity formed between an outside insert and an inside insert and after the melt molding raw material is cooled and solidified, the inside insert is pulled out and released from the hollow part and an apparatus for a mold of injection molding for it. SOLUTION: The inside inserts 5 are pulled out from the hollow part of a hollow molded article 2 by moving two inside inserts 5 respectively left and right on a base stage 3 to open the mold under a condition where the faces 12 of both sides of the hollow molded article 2 are held by means by apexes 10 of two inclined pins 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for injection molding a hollow molded article which is elongated and empty inside, and to an injection molding die apparatus therefor.

[0002]

2. Description of the Related Art Conventionally, for example, as shown in a perspective view of a hollow molded product in FIG. 8A and a side sectional view of the hollow molded product in FIG. Injection molding of the molded product 2 is performed by injecting a molding material into a cavity between an outer nest forming the outside of the hollow molded product 2 and an inner nest forming the hollow portion 1 and cooling and solidifying the molding material. The mold is opened to take out the hollow molded article 2 from the cavity.
After the outer nest forming the outside of the mold is released from the mold, the hollow molded article 2
When the inner insert forming the hollow portion 1 is formed in the order of opening the mold, the position of the hollow molded product 2 is shifted due to the occurrence of mold release resistance generated between the inner insert and the inner wall of the hollow molded product 2. Or
The hollow molded article 2 was elongated and whitened.

[0003]

According to the above-mentioned conventional injection molding method for a hollow molded article, the position of the hollow molded article is shifted due to the release resistance when the inner nest is released from the hollow molded article. Since the position of the hollow molded product cannot be determined, the hollow molded product cannot be chucked by a robot, which causes a problem in mass production, and a problem that a stable good product cannot be obtained due to whitening or the like based on the elongation of the hollow molded product.

The present invention solves the above-mentioned problems. When the inner nest is released from a hollow molded product, the position of the hollow molded product does not shift due to mold release resistance, and the hollow molded product does not elongate. It is an object of the present invention to provide an injection molding method for a molded article and an injection molding die apparatus therefor.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a method of forming a hollow molded product between an outer nest forming an outer side and an inner nest forming a hollow portion of the hollow molded product. The cavity formed in the mold is filled with the molten molding material, and after cooling and solidifying the molten molding material, the outer nest is released and the inner nest is hollow-formed while holding both end surfaces of the hollow molded product with inclined pins. This is an injection molding method of a hollow molded product that is pulled out and released from the hollow part of the product.When the inner nest is pulled out from the hollow part of the hollow molded product and released from the mold, the position of the hollow molded product is shifted due to the release resistance, Elongation does not occur in the molded article.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is formed between an outer nest forming the outside of a hollow molded article and an inner nest forming a hollow portion of the hollow molded article. After the molten molding material is filled into the cavity, and the molten molding material is cooled and solidified, the outer nest is released and the inner nest is hollowed out while holding both end surfaces of the hollow molded product with the inclined pins. It is an injection molding method of a hollow molded product that is pulled out from the part and released from the mold,
When the inner nest is pulled out of the hollow part of the hollow molded product and separated from the mold, the inclined pins hold both end surfaces of the hollow molded product, so the mold release resistance generated between the inner nest and the hollow molded product This has the effect that the position of the hollow molded article does not shift and the hollow molded article does not expand.

According to a second aspect of the present invention, there is provided an outer nest forming the outside of a hollow molded product, an inner nest forming a hollow portion of the hollow molded product, an outer nest and an inner nest. 2. An inclined pin for holding both end surfaces of a hollow molded product formed in a cavity between the inner molds when the inner insert is released from the mold.
An injection molding mold apparatus for performing the injection molding method of a hollow molded product according to the above, wherein the position of the hollow molded product is shifted by inclined pins that hold both end surfaces of the hollow molded product when the inner nest is released. And the hollow molded article does not elongate.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment) FIG. 1, FIG. 2, FIG. 3, FIG.
5 and 6 are side views in which the states of respective steps of the injection molding die apparatus according to the embodiment of the present invention are arranged in the order of steps, and FIG. 7 is an inclined view used for the injection molding die apparatus according to the embodiment of the present invention. It is an enlarged side view of a pin.

FIG. 1 shows that two outer nests 4 movable on a base 3 are closed from both sides to form an outer shape of a hollow molded article 2.
Similarly, two inner nests 5 movable on the base 3 are inserted into the outer nest 4 from both sides to form a hollow portion of the hollow molded product 2 between the outer nest 4 and the inner nest 5. 3 shows a state a in which a cavity formed in the mold is filled with a molten molding material such as a molten resin. Reference numeral 6 denotes an inclined pin that is not yet used in this state. The base 9 is attached to an ejector plate 8 that can move up inside the recess 7 of the base 3.
The distal end 10 can protrude from the upper surface of the base 3 through the through hole 11 of the base 3.

FIG. 2 shows that after the molten molding material has cooled and solidified,
A state b in which the outer shape of the hollow molded article 2 appears to the outside by the two outer nests 4 moving on the base 3 to the left and right, respectively, and opening the mold.

FIG. 3 shows that the ejector plate 8 rises in the recess 7 of the base 3, and the tips 10 of the two inclined pins 6 with the base 9 attached to the ejector plate 8 are connected to the through holes 11 of the base 3. The state c which protrudes to the upper surface of the base 3 through the base 3 and holds the end surfaces 12 on both sides of the hollow molded article 2 is shown.

FIG. 4 shows a state d in which the hollow molded article 2 is robot-chucked by the take-out machine 13.

FIG. 5 shows, as shown in FIG. 3 above, the end faces 12 on both sides of the hollow molded article 2 with the tips 10 of the two inclined pins 6.
In a state where the inner nest 5 is pulled out from the hollow portion of the hollow molded product 2, the two inner nests 5 are moved left and right on the base 3 to open the mold while holding the inner nest 5. ing.

FIG. 6 shows a state f in which the hollow molded article 2 robot-chucked by the take-out machine 13 is taken out.

The details of the state in which the inclined pin 6 is swingably attached to the ejector plate 8 are described below.
It is as showing in the expanded side view of the inclination pin of FIG. That is, the base 9 of the inclined pin 6 is moved by the block 16 on the sliding plate 15 that slides in the recess 14 of the ejector plate 8.
And a tilting guide 17 for guiding the tilting pin 6 which is parallel-moved by sliding of the sliding plate 15,
It is formed in a through hole 11 of the base 3 through which the inclined pin 6 passes.

According to the injection molding apparatus having the above construction, the hollow molded product 2 is taken out from the cavity formed between the outer nest 4 and the inner nest 5 so that the hollow portion of the hollow molded product 2 is removed. When the inner nest 5 is pulled out from the inside, since the end surfaces 12 on both sides of the hollow molded product 2 are held by the tips 10 of the two inclined pins 6, the inner nest 5 and the inner wall of the hollow molded product 2 are interposed. The position of the hollow molded article 2 does not shift due to the generated release resistance, and the hollow molded article 2 does not expand and whiten.

[0018]

As described above, according to the method for injection molding a hollow molded article of the present invention and the injection molding die apparatus thereof, when the hollow molded article is taken out from the injection molding die apparatus, the position of the hollow molded article is determined. Since there is no deviation, a robot chuck can be used, mass productivity is improved, and since the hollow molded product does not expand and whiten, a stable good product can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view showing a state a of an injection mold apparatus according to an embodiment of the present invention.

FIG. 2 is a side view showing a state b of the injection molding die apparatus according to the embodiment of the present invention.

FIG. 3 is a side view showing a state c of the injection molding die apparatus according to the embodiment of the present invention.

FIG. 4 is a side view showing a state d of the injection mold apparatus according to the embodiment of the present invention.

FIG. 5 is a side view showing a state e of the injection mold apparatus according to the embodiment of the present invention.

FIG. 6 is a side view showing a state f of the injection mold apparatus according to the embodiment of the present invention.

FIG. 7 is an enlarged side view of an inclined pin of the injection molding die apparatus according to the embodiment of the present invention.

FIG. 8A is a perspective view of a hollow molded article. FIG. 8B is a side sectional view of the hollow molded article.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hollow part 2 Hollow molded product 3 Base 4 Outer insert 5 Inner insert 6 Inclined pin 7, 14 Recess 8 Ejector plate 9 Base 10 Tip 11 Through-hole 12 End face 13 Extractor 15 Slide plate 16 Block 17 Incline guide

Claims (2)

[Claims] 1. A molten molding material is filled into a cavity formed between an outer nest forming the outside of a hollow molded product and an inner nest forming a hollow portion of the hollow molded product. A method of injection molding a hollow molded product, wherein after cooling and solidifying, the outer insert is released from the mold, and the inner insert is pulled out of the hollow portion of the hollow molded product and separated from the hollow molded product while holding both end surfaces of the hollow molded product with the inclined pins. 2. An outer nest forming the outside of a hollow molded product, an inner nest forming a hollow portion of the hollow molded product, and a hollow molding formed in a cavity between the outer nest and the inner nest. 2. An injection molding apparatus for performing an injection molding method for a hollow molded product according to claim 1, further comprising an inclined pin for holding both end surfaces of the product when the inner insert is released from the mold.