JPH09277314A - Mold for injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the demolding of an undercut by a method in which the undercut is formed in the fixed side plate in a cavity, a locking block for fixing slide cores is mounted on a runner stripper plate, and angular pins to be guided are fixed on both sides of the block. SOLUTION: A cavity 9 is formed in which a fixed side plate 2, a moving side plate 1, and a two-inside-way undercut 5a between slide cores 4a, 4b are molded. In the slide cores 4a, 4b, guide holes 16a, 16b for guiding angular pins 6a, 6b respectively are formed, and additionally slide returning springs 13a, 13b which press the slide cores 4a, 4b inside toward each other are installed to demold the undercut 5a when a mold is opened. Besides, a locking block 7 for fixing the slide cores 4a, 4b is attached to a runner stripper plate 3, and the angular pins 6a, 6b are fixed on both sides of the block 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold used for injection molding of a molded product having an undercut portion, and more particularly to a mold for injection molding of a molded product having an undercut in a twin direction.

[0002]

2. Description of the Related Art There are various shapes of undercut portions of injection molded products. An example of this shape is shown in FIG. The molded product shown in FIG. 6 (a) has an undercut portion 60a formed in a twin-inward direction, and the molded product shown in FIG. 4 (b) has an undercut portion 60b formed in a twin-outward direction. is there. Further, the one shown in FIG. 7C is a molded product provided with a through hole 61c. The molded product shown in FIG. 7D has the undercut portion 60d formed in one direction.

Molds used for injection molding of molded products having undercuts of various shapes are, for example,
The one shown in FIG. 7 is generally used. This mold 7
Reference numeral 0 indicates an example of a mold for molding a molded product provided with a through hole. The mold 70 includes a fixed-side mold 72, a movable-side mold 71 that can approach and separate from the fixed-side mold 72, and a space between the fixed-side mold 72 and the movable-side mold 71. And a slide core 73 movably supported in a direction orthogonal to the moving direction of the moving die 71, and a cavity 77 is formed between them. Further, the through hole 77b is formed by projecting the core pin 75 from the slide core 73 through the through hole 77b.
The push-cut surface 75a is formed so as to come into contact with the inner surface of the cavity 77.

As shown in FIG. 7, the mold release using the mold 70 is performed by moving the moving mold 71 and the slide core 73 in the H direction to separate them from the fixed mold 72, and then the slide core 73. By sliding the mold on the moving side mold 71 in the J direction, releasing the undercut portion 77a, and further projecting the core pin 75 in the I direction, the releasing of this molded product is completed. .

The molded product having the through hole 61c shown in FIG. 6 is molded as described above by using the mold shown in FIG. 7. The mold is shown in FIGS. 6 (b) and 6 (d). A molded product having a shape shown in () can be similarly molded. Further, in the case of the molded product having the shape shown in FIG. 3A, the undercut 60a is formed in the fixed side mold (not shown), and the fixed side undercut 60a is the slide core attached to the fixed side. Using an external force device such as a hydraulic cylinder or a pneumatic cylinder, the product was released by forcibly moving it before the product plate was opened.

[0006]

By the way, as described above, in the prior art, when a molded product having an undercut shape in the twin inner direction as shown in FIG. Since an external force device such as a cylinder or a pneumatic cylinder has to be attached, the structure of the entire molding machine has to be complicated, resulting in high cost. That is, the use of such an external force device also prolongs the molding time and reduces the durability of the mold.

The present invention has been made in view of the above points, and can be applied to mold release of a molded product having an undercut shape in the twin inner direction, and the undercut mold release process can be smoothly advanced. An object of the present invention is to provide a mold for injection molding which can be done and which does not require the use of an external force device.

[0008]

In order to achieve the above object, an injection mold of the present invention comprises a stationary plate and a fixed plate.
The stationary plate is provided with a movable plate which can be moved toward and away from the stationary plate, and a runner which is disposed on the opposite side of the stationary plate with the stationary plate interposed therebetween and in which a flow path of injection molding material is formed. And a runner stripper plate, the fixed side plate is provided with two slide cores, and the fixed side plate, the moving side plate, and the contour of a molded product to be molded between the two slide cores. A mold having a cavity formed therein, wherein the cavity has a shape in which an undercut in a twin direction is formed in the fixed side plate, and angular guide pins are respectively guided to the two slide cores. Guide holes are formed, and in the vicinity of these slide cores, the directions in which the slide cores move inward relative to each other. A pressing means for pressing is provided, a locking block for fixing the slide core is provided on the runner stripper plate, and the locking block is guided on both sides of the locking block to the respective guide holes. Characterized by the presence of Angular Pins.

Further, it is preferable that a slide unit including the slide core and a slide core holder for holding the slide core is detachably provided on the fixed side plate. The slide core holders are provided with pressing means for pressing the slide cores in directions in which the slide cores move inward.

[0010]

The two slide cores provided on the fixed side plate are inwardly (on the side of the locking block) by the pressing means.
The pressing force is applied to. Therefore, the runner stripper plate separates from the fixed side plate, and the two slide cores move inwardly in association with the operation of the angular pin leaving the guide hole. As a result, the undercut in the twin inner direction is released from each of the two slide cores.

In addition, in the construction using the slide unit, in addition to the above-mentioned operation, the slide unit can be directly attached to and detached from the fixed side plate, so that the work is simplified and the maintenance with the mold attached to the molding machine is facilitated. It will be possible.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing the structure of an injection molding die suitable for use in the implementation. 1 (a) shows the respective states when the mold is clamped and FIG. 1 (b) shows the respective states when the mold is opened.

In this injection molding die 10, a movable side plate 1 and a runner stripper plate 3 are arranged so as to sandwich the fixed side plate 2 so that they can be moved toward and away from the fixed side plate 2. The fixed side plate 2 is provided with two slide cores 4a and 4b, and the fixed side plate 2, the moving side plate 1 and the two slide cores 4 are provided.
A cavity 9 corresponding to the contour of the molded product 5 to be molded is formed between a and 4b. The cavity 9 has a shape in which a twin-sided undercut 5 a is formed on the fixed side plate 2.
Guide holes 16a and 16b for guiding the angular pins 6a and 6b are formed in a and 4b, respectively.
Further, slide return springs 13a and 13b for applying a pressing force for pressing the slide cores 4a and 4b inwardly toward each other are provided on the fixed side plate 2 near the slide cores 4a and 4b. It is provided. On the other hand, the runner stripper plate 3 is provided with a locking block 7 for fixing the slide cores 4a, 4b, and angular pins 6a, 6b guided by respective guide holes 16a, 16b are provided on both sides of the locking block 7. Has been.

The runner stripper plate 3 includes
A branched runner (not shown) is provided, and the molding material is filled in the cavity 9 through the runner and a gate (not shown).

In this injection molding die 10, when the mold is clamped, the two slide cores 4a, 4b are pressed inward (on the locking block side) by the slide return springs 13a, 13b. Therefore, when the mold is opened, the runner stripper plate 3 separates from the fixed side plate 2 (direction A in the drawing), and the angular pins 6a, 6
In conjunction with the movement of b leaving the guide holes 16a, 16b,
The two slide cores 4a and 4b slide inward (in the direction B in the figure), so that the undercut 5a in the inner direction is separated from the two slide cores 4a and 4b. There is.

Next, the operation of the injection molding die 10 having the above construction will be described. FIG. 2 is a diagram showing this operation over time. First, as shown in FIG. 4A, after the molding material is injected and the mold is clamped, the pressure is maintained and cooled, and then the runner portion PL is opened as shown in FIG. As a result, the fixed side plate 2 and the runner stripper plate 3 are separated from each other, and with this separating operation, as described above, the fixed return slide cores are moved inward by the slide return springs to move in the twin direction. The undercut is released (not shown).

Next, as shown in FIG.
L opens. As a result, the fixed plate 2 and the movable plate 1 are separated from each other, and the molded product 15 is released from the fixed plate 2.

Then, the runner stripper plate 3 moves from the holding plate 17 and separates from it. Here, in order to prepare for the next molding cycle, the runner in the runner stripper plate 3 is taken out (or unnecessary material is removed).

In this embodiment, an external force device such as a hydraulic cylinder is not required to move the fixed side slide cores 4a and 4b in the inward direction, and therefore, the core circuit of the molding machine is not required. Need not be provided. As a result, the range of choices for the molding machine is widened and the time required for setup is shortened. Also, the durability of the mold is improved and the reliability of the mold is improved. Further, it is possible to reduce the manufacturing cost and manufacturing time of the mold, reduce the size of the mold, and realize downsizing. And in the production of molded products,
Molding time can be shortened and productivity is improved.

Next, another embodiment of the present invention will be described. FIG. 3 is an exploded perspective view of a slide core portion of an injection molding die applied to this other embodiment.

In this example, the slide unit 2 in which the slide cores 4a and 4b having the shapes shown in the figure and the slide core holder 8 for holding them are one unit.
0 is provided on the fixed side plate 2,
There is a feature in this point. The members shown in the exploded perspective view are combined with each other, and the state at the time of mold clamping is shown in FIGS. 4 and 5. Note that FIG. 4 is a sectional view seen from the S direction shown in FIG. 3, and FIG. 5 is a sectional view seen from the T direction.

As shown in FIG. 4, the slide unit 20 is fitted in the fixed side plate 2, and the slide core holder 8 is fixed by bolts 11a.
A slide rail 12 is provided so that the slide core 4 slides smoothly in the slide core holder 8, and the slide rail 12 is fixed by a bolt 11b.

Further, as shown in FIG. 5, the two slide cores 4 are inserted from the slide core holder 8 side to the two slide cores 4 by the slide return springs 13, respectively. The pressing force is applied so that it can slide in one direction. At the time of mold clamping, the angular pin 6 is inserted into the guide hole, and the locking block 7 has two slide cores 4
The two slide cores 4 are maintained in a fixed state. Although not shown, the locking block 7 and the angular pin 6
Is provided on the runner stripper plate as in the above-described embodiment.

Now, the operation of shifting from the mold clamping state to the mold opening state will be described below. With the separation of the runner stripper plate and this fixed side plate 2,
The angular pin 6 separates from the guide hole. With this separation, the locking block 7 also separates. With this operation, the two slide cores 4 slide inward by the pressing force of the slide return spring 13, and the undercut portion 10a is released. The subsequent step of releasing the molded product is the same as that of the embodiment described above.

In this embodiment, the same effects as those of the previous embodiment can be obtained, and further, the following effects are peculiar to this embodiment. Both the slide core 4 and the slide core holder 8 can be detached from the product part PL while the mold is attached to the molding machine. Therefore, if this slide unit 20 is removed from the product part PL, the mold can be maintained on the molding machine, and the labor for manufacturing can be saved.

[0026]

As described above, in the injection molding die of the present invention, the cavity has a shape in which the undercut in the twin direction is formed in the fixed side plate, and the guide holes are formed in the two slide cores. Providing a pressing means for pressing the slide cores in the vicinity of these slide cores in a direction in which they move inward to each other, and a locking block and an angular pin guided by a guide hole on the runner stripper plate. Since the two slide cores provided on the fixed side plate are provided with a pressing force inward (on the side of the locking block) by the pressing means, the runner stripper plate moves away from the fixed side plate. By interlocking, these two slide cores can be moved inward relative to each other, and the undercut in the bi-inward direction can be performed as in the conventional case. Without using an external force device, such as a hydraulic cylinder, it can be easily demolded.

As a result, the range of choices for the molding machine is widened, and the time required for setup is shortened. Also, the durability of the mold is improved and the reliability of the mold is improved. Further, it is possible to reduce the manufacturing cost and manufacturing time of the mold, reduce the size of the mold, and realize downsizing. Then, in the production of the molded product, the molding time can be shortened and the productivity can be improved.

When the slide unit is detachably provided on the fixed side plate, in addition to the above-mentioned effects, the slide core and the slide core holder are detached from the product part PL while the mold is still attached to the molding machine. Can be possible. As a result, if this slide unit is removed from the product part PL, the mold can be maintained on the molding machine, and the labor for manufacturing can be saved.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an injection molding die applied to an embodiment of the present invention.

FIG. 2 is a view for explaining the operation of the injection molding die applied to the embodiment of the present invention over time.

FIG. 3 is an exploded perspective view of a main part of an injection molding die which is applied to another embodiment of the present invention.

FIG. 4 is a cross-sectional view of the main part of the injection molding die as viewed from the S direction in FIG.

5 is a cross-sectional view of the main part of the injection molding die as seen from the T direction in FIG.

FIG. 6 is a sectional view of an injection-molded product having an undercut portion.

FIG. 7 is a view for explaining the configuration and operation of a conventional injection molding die.

[Explanation of symbols]

1 ... Moving plate 2 ... Fixed plate 3 ... Ranna stripper plate 4, 4a, 4b ... Fixed slide core 5a ... Undercut 6, 6a, 6b ... Angular pin 7 ... Locking block 8 ... Slide core holder 9 Cavities 13, 13a, 13b Slide return springs 16a, 16b Guide hole 20 Slide unit

Claims (2)

[Claims] 1. A fixed-side plate, a movable-side plate that can approach and separate from the fixed-side plate, and an injection-molding material that is disposed on the opposite side of the fixed-side plate from the movable-side plate. And a runner stripper plate having a runner in which the flow path is formed, the fixed side plate is provided with two slide cores, and the fixed side plate, the moving side plate, and the two slide cores are provided between the two slide cores. A mold in which a cavity corresponding to the contour of a molded product to be molded is formed, and the cavity has a shape in which an undercut in a twin direction is formed in the fixed side plate. Guide holes for guiding the angular pins are formed in the slide cores, and the slide cores are provided near the slide cores. A pressing means is provided for pressing the two inward in a mutually moving direction, a locking block for fixing the slide core is provided on the runner stripper plate, and both sides of the locking block are provided. An injection molding die characterized in that an angular pin that is guided in each of the above-mentioned guide holes is provided in the. 2. A slide unit including the slide core and a slide core holder for holding the slide core is detachably provided on the fixed side plate, and the slide core holder has the slide unit. The injection molding die according to claim 1, further comprising a pressing unit that presses the cores in a direction in which the cores move inward.