JPH0694149B2 - Mold release method in injection molding - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold releasing method in which a molded article injection-molded with a thermoplastic synthetic resin using a molding die is opened and then taken out from the die.

[0002]

2. Description of the Related Art Generally, in an injection molded product of a synthetic resin product, various mold releasing means are used for releasing the molded product from the mold after completion of mold opening. Since traces based on the traces remain on the appearance of the molded product and cause a cosmetic defect and reduce the commercial value, the traces are devised so as to be inconspicuous as much as possible, and many requests for improvement have been made. In conventional injection-molded products, the through-holes, holes, or depressions that are formed have a large release resistance when the product is released from the mold, and especially when the synthetic resin material used has a large shrinkage rate during the molding, the release resistance is Because of its large size, it has been attempted to install a protruding pin for releasing the mold in this vicinity, and a mold releasing system by pushing out a part of the product such as a stripper plate or a sleeve.

[0003]

However, in any of the methods, it is limited to the case where the through holes and the depressions provided in the product are circular, the shape of the product is greatly restricted, and the release traces are not conspicuous on the product. There are many restrictions on the external appearance of the position, and there are problems such as lack of freedom in design. INDUSTRIAL APPLICABILITY The present invention eliminates these conventional drawbacks, does not limit the shape of the insert member, does not leave a mold release trace, and can significantly simplify the mold release treatment to produce a molded product. It is an object of the present invention to provide an effective mold release method capable of producing an injection-molded article having a high commercial value without any defects in appearance.

[0004]

SUMMARY OF THE INVENTION According to the present invention, when a molded product having a through hole or a recess formed by injection molding using a mold having a cavity is released from the mold after the mold is opened, the through hole is used. Alternatively, the insert member used to form the recess is divided into a fixed insert member and a movable insert member, and at least one of the movable insert members is formed along the divided surface together with the molded product. This is a mold releasing method in injection molding characterized in that it is ejected from the movable mold, removed, and then pulled back to a predetermined position to bring the molded product into contact with the movable mold and release it from the movable insert member.

[0005]

[Function] The movable die is slid to fit into the fixed die, the raw material is filled and cooled in the cavity in which the insert member is projecting, and a molded product is produced, but the movable die is retracted after the molding process is completed. Then, the mold is moved to the product discharge position and the mold is opened. After the mold opening is completed or during the mold opening, the movable insert member is ejected from the cavity, the molded product is removed from the movable mold, and then the movable insert member is actuated to return it to the original position in the cavity again to be ejected. The molded product is left on the parting surface of the movable mold, and the movable insert member is pulled out for more reliable mold release, and the traces are also in the through holes and dents, and the product is released with a good appearance. be able to.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to an embodiment with reference to FIG. 1. A molded product 1 is injection-molded by using a fixed mold 2 and a movable mold 3 which define a cavity 10. molded article 1 having a through-hole 1 ₁ or indentation molded
The upon release after mold opening of the mold, the through-hole 1 ₁ or depressions nesting member used to form the divides into a plurality of the fixed insert member 5 and the movable insert member 4 Is provided by
At least one of the movable insert members 4 is ejected from the movable mold 3 along with the molded product 1 along the dividing surface to be removed, and then pulled back to a predetermined position to bring the molded product 1 into contact with the movable mold 3. The movable insert member 4 is released from the mold, and the molded product 1 is released from the movable mold 3 of the molding die.

[0007] The insert member of the die member that forms the through hole 1 ₁ or depressions, be comprised of a movable insert member 4 with a separating surface fixed insert member 5 which, the after mold opening completion The movable insert member 4 is ejected and pulled back together with the molded product 1 to release the molded product 1 from the movable mold 3, but the fixed insert member 5 is not a part of the movable mold 3 but a separate member. It can also be configured with. Also, the through hole ₁₁
The movable nesting member 4 forming the step is provided with a step or chamfer at a position away from the tip end without forming a draft or an inverse gradient, has an outer peripheral surface of a straight sliding surface, and is divided in parallel to the outer peripheral surface. It is preferable that the surface is separated into a plurality of parts from the fixed insert member 5 and is advanced from the cavity in the protruding direction, and then returned to the original position to release the molded product 1 from the movable mold 3 and further penetrates. fixed insert member bore 1 ₁ or depressions 5 may have a gradient of slope opposite dropout. Incidentally, as the movable insert member 4, a part or all of the through-hole 1 _1, which is formed as a movable mold side, used after made independent from the cavity 10 a portion forming the through hole as a nesting Is good.

[0008] In the case of the through hole 1 _1, although a part of the insert member forming a through-hole 1 ₁ as the movable side is considered to be in a manner such that there is no valid draft, after molding The insert member 4 may be projected from the cavity 10 during mold opening (after resin cooling) and may be operated so as to return to the original position.

As the molding die, as shown in FIG. 2, the cavity 10 formed between the fixed die 2 and the movable die 3 is filled with resin and cooled, and then the movable die 3 is fixed. Molded product 1 made of resin cooled so as to retract from 2
Is attached to the movable mold 3, the base of the movable insert member 4 is attached to the mold plate 6, and one end of the movable insert member 4 slides into the cavity 10 in whole or in part. You can do it. Then, in order to release the molded product 1, the movable insert member 4 is projected by the actuating member 8 through the connecting rod 7, and the movable insert member 4 is operated to return to its original position to form the molded product 1. Take it out of the mold. That is, FIG.
As shown in Fig. 3, when the movable mold 3 is retracted from the fixed mold 2 and the mold is opened (Fig. 3a), the upper surface side of the molded product 1 immediately after mold opening is released (Fig. 3b). When the movable insert member 4 is moved forward, the molded product 1 also moves accordingly,
It is detached from the movable mold 3 and the fixed insert member 5 and is ejected. Then, the molded product 1 instantly shrinks, and the through hole ₁₁ also becomes smaller (FIG. 3c). Next, when the retracting operation of returning the movable insert member 4 to the original position is performed, the molded product 1 comes into contact with the movable mold 3, but the through hole ₁₁ or the recess of the molded product 1 is molded without entering the original recessed part. The product 1 is caught by the fixed insert member 5, and the movable insert member 4 is pulled out from the molded product 1 in the state where the molded product is left on the movable mold 3 (FIG. 3d) (FIG. 3).
e). In this case, the height of the fixed insert member 5 acts as a mold release stroke of the molded product 1 and the mold release cycle can be performed efficiently with a minimum. The fixed mold 2 is on the mold mounting plate 12, and the movable mold 3 is the mold plate 6 and the support 9.
It is provided on the mold mounting board 13 via the, and a parting surface 11 is formed between the two molds 2 and 3 facing each other.

[0010] In the example of FIG. 4, the as-molded article 1 insert member 4 having a reverse gradient so as to form a tapered through-hole 1 _1, during the reinsertion of該入Ko member 4, the molded article The mold release can be further ensured by the projection of the molded product without entering all the through holes or depressions.

It should be noted that when the insert member 4 is pulled out from the molded product 1, the product shrinks instantly, and the inner diameter of the through hole ₁₁ or the recess becomes smaller than the outer peripheral size of the insert member 4. Although it may be used as a resistance at the time of pulling out, it is also possible to consider so as not to enter into the through hole ₁₁ or the recess after positively pulling out the nesting member 4 as in the example of FIG. 3e. It can be selected depending on the shape of the member 4. In these cases, the movable die 3 side portion or recess of the depth of the through hole 1 _1, it is preferable to consider to act as a stroke during the release of the molded product 1. Further, although the fixed insert member 5 of the through hole 1 ₁ is provided with a gradient opposite to the slope, the length of the fixed insert member 5 of the through hole 1 ₁ is made larger than the depth of the movable portion of the molded product 1. This makes it easier to release the molded product 1 from the cavity 10. May also be release by the contraction straight without providing a reverse slope to the movable portion of the through-hole 1 _1.

[0012]

INDUSTRIAL APPLICABILITY According to the present invention, when the insert member for forming the through hole or the recess is arranged in the cavity of the molding die and the injection-molded article is released from the die by opening the die, the penetration is performed. An insert member used to form a hole or a recess is provided in a plurality of divided parts in a fixed insert member and a movable insert member, and at least one of the movable insert members is formed along a dividing surface. At the same time, it is ejected from the movable mold, removed, and then pulled back to a predetermined position to bring the molded product into contact with the movable mold and release it from the movable insert member.
Molded products can be manufactured without being restricted by the shape of the insert member and leaving a mold release trace, and mold release processing can be significantly simplified. In addition to being able to produce molded products, there are no restrictions on the appearance for mold release, the degree of freedom in product design can be greatly expanded, and there are practical effects such as being suitable for mass production.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a part of a use state of an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of a device incorporated showing one usage state of the example of FIG.

FIG. 3 is a vertical cross-sectional view of a part of the operating state of the mold releasing process of the example of FIG.

FIG. 4 is a plan view of a molded product manufactured by the method of the present invention.

5 is a vertical sectional view taken along line AA of FIG. 4, b is a vertical sectional view taken along line BB of FIG. 4, and c is a vertical sectional view taken along line CC of FIG.

[Explanation of symbols]

1 Molded product 1 ₁ Through hole 2 Fixed mold 3 Movable mold 4 Movable insert member 5 Fixed insert member 6 Mold plate 7 Connecting rod 8 Actuating member 9 Support 10 Cavity 11 Parting surface 12 Mold mounting board 13 Mold External board

Claims (2)

[Claims] 1. A molded article having a through hole or a dent, which is injection-molded by using a molding die having a cavity, is used for forming the through hole or the dent when the mold is released from the mold after the mold is opened. The insert member is divided into a fixed insert member and a movable insert member, and at least one of the movable insert members is moved along the dividing surface by protruding from the movable mold together with the molded product. A mold releasing method in injection molding, characterized in that, after removing, the molded product is pulled back to a predetermined position and a molded product is brought into contact with a movable mold and released from a movable insert member. 2. A movable nesting member forming the through hole,
A molded product that has an outer peripheral surface of a straight sliding surface, is separated into a plurality of fixed insert members by a dividing surface parallel to the outer peripheral surface, and advances in the protruding direction from the cavity, and then returns to the original position again. The mold releasing method in injection molding according to claim 1, wherein the mold is released from the mold.