JPH06143367A - Mold releasing method in injection molding - Google Patents

Abstract

PURPOSE:To manufacture a molded piece in a remarkably simplified mold release processing without restriction of shape of an insert member and without leaving trace of the mold release by a method wherein the insert member is pulled out from the molded piece and is inserted into an original position again so as to release the molded piece from a mold. CONSTITUTION:A molded piece 1 is formed in injection molding by using a fixed mold 2 for divisionally forming a cavity 10 and a movable mold 3, and the molded piece is released from the mold. At this time, an insert member 4 for forming a through hole or a recess in the cavity 10 is arranged. When the formed molded piece is to be released from the movable mold 3 by means of mold opening, the insert member 4 is pulled out from the molded piece 1 through a working member 8. Thereafter, the member 4 is again inserted into an original position so as to release the molded piece 1 from the mold. For the member 4, an insert member wherein a part or the whole of the through hole 5 to be formed is made to be at the movable mold side and the part forming the through hole is made to be independent from the cavity 10 as an insert is used.

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 ratio during the molding, the release resistance is large. Because of its large size, it has been attempted to install an ejector pin for releasing the mold in this vicinity, or a mold releasing method by ejecting a stripper plate or a sleeve for pushing a part of the product.

[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]

DISCLOSURE OF THE INVENTION The present invention provides a molded product injection-molded with a nesting member for forming a through hole or a recess in a cavity of a molding mold, and released from the mold by opening the mold. In this case, the mold releasing method in injection molding is characterized in that after inserting the insert member from the molded product, the insert member is again inserted into the original position to release the molded product from the mold.

[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 completion of mold opening or during mold opening, the insert member is pulled out from the cavity, and once the insert member is removed from the product, the insert member is activated to return it to the original position in the cavity again, and the product is ejected. It is possible to more reliably release the product, and the product can be released with a good appearance because there are traces in the through holes and the depressions.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to an embodiment with reference to FIG. 1. When a molded product 1 is injection-molded using a fixed mold 2 and a movable mold 3 that form a cavity 10 and then released. , The operating member 8 is provided with the insert member 4 for forming a through hole or a recess in the cavity 10 when the mold product is opened to release the insert member 4 from the movable mold 3. After being pulled out from the molded product 1 via the insert member 4, the insert member 4 is again inserted into the original position to release the molded product 1 from the mold.

The molding die is composed of a fixed die 2 and a movable die 3, and the insert member provided in the movable die 3 after completion of the opening of the movable die 3 or during the opening of the die. 4, the movable portion of the through hole is not provided with a draft, the length of the movable portion of the through hole is made larger than the depth of the movable portion of the product, and the product can be ejected by operating the operating means. As the insert member 4, it is preferable to use a part or the whole of the through hole 5 to be formed on the movable mold side, and the part forming the through hole is an insert and is independent of the cavity 10. Good.

In the case of the through hole 5, a part or the whole of the through hole 5 is set to the movable side, but the movable side portion or the recessed portion of the through hole 5 should not have an effective draft gradient. In consideration of the above, it is preferable that the insert member 4 is pulled out from the cavity 10 during mold opening after molding (after resin cooling), the insert member 4 is removed from the product, and it is returned 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. 2, the resin molded product 1 cooled at this time is still attached to the movable mold 3, the root of the insert member 4 is attached to the mold plate 6, and penetrates the movable mold 3. Through hole 5
One end of the insert member 4 projects entirely or partially into the cavity 10. The inner diameter of the through hole 5 is slightly larger than the outer diameter of the insert member 4 so that the insert member 4 can smoothly slide in the through hole 5. Then, in order to release the molded product 1, the movable mold 3 and the mold plate 6 are pulled apart, and the tip of the insert member 4 is inserted into the cavity 1 via the connecting rod 7.
After completely retracting it from inside 0, the operating member 8 causes the nesting member 4 to re-project through the connecting rod 7 and is operated to return the nesting member 4 to the original position to take out the product from the mold. To The fixed mold 2 is mounted on the mold mounting plate 12, and the movable mold 3 is mounted on the mold mounting plate 1 via the mold plate 6 and the support 9.
3, a parting surface 11 is formed between the two molds 2 and 3 facing each other.

In the example of FIG. 3, the molding member 1 is a nesting member 4 provided with an inverse gradient so as to form a tapered hole,
When the insert member 4 is reinserted, the product can be more reliably released by the product which is not projected into the through hole or the recess of the product and is projected.

It should be noted that, when the insert member 4 is pulled out from the molded product 1, the product instantly shrinks, and the inner diameter of the through hole or the recess is smaller than the size of the insert member 4. Although it may be used as a resistance during the projecting operation,
After positively pulling out the insert member 4 as in the example, it is also possible to consider not to enter the through hole or the recess depending on the shape of the insert member 4. In these cases, it is preferable to consider that the depth of the portion of the through hole on the movable mold 3 side or the depression acts as a stroke at the time of releasing the product.

[0012]

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. After pulling out the child member from the molded product, insert the nesting member again into the original position and release the molded product from the mold, leaving a release mark without being restricted by the shape of the nesting member. Without needing to be able to manufacture a molded product by significantly simplifying the mold release process, producing an injection-molded product of high commercial value with no defects in the appearance of the molded product. The above restrictions are eliminated, 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 partial vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a cut side view of the device showing a usage state of the example of FIG.

FIG. 3 is a longitudinal sectional view of a part of another embodiment of the present invention.

[Explanation of symbols]

 1 Molded Product 2 Fixed Die 3 Movable Die 4 Nesting Member 5 Through Hole 6 Mold Plate 7 Connecting Rod 8 Actuating Member 9 Support 10 Cavity

Claims (3)

[Claims] 1. A nesting member is formed when a molding member injection-molded by arranging a nesting member for forming a through hole or a depression in a cavity of a molding die is released from the die by mold opening. A mold releasing method in injection molding, characterized in that, after being pulled out from the product, the insert member is again inserted into the original position to release the molded product from the mold. 2. After the movable mold of the molding mold is completely opened, the insert member provided in the movable mold is pushed and retracted with a stroke larger than the depth of the movable side portion of the molded product to form the molded product. The mold releasing method according to claim 1, wherein the releasing is performed. 3. A cavity is formed with a part or all of the through hole formed by the insert member as the movable mold side and an inverse slope is provided in the movable side portion of the through hole, and the part forming the through hole as the insert. The mold releasing method according to claim 1, wherein a more independent one is used.