JPH10323867A - Die for dichroic molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent surely both slide cores from colliding against each other in clamping by a method wherein slide control axes provided to a pair of dies are slightly inclined to an opening and closing slide central axis of a movable die. SOLUTION: A movable die 2 is slide bonded to a fixed die 1 under a state wherein both slide cores 3, 4 are respectively projected to respective advanced positions. Since slide central axes P1, P2 of both slide cores 3, 4 are inclined by an angle θ to an opening and closing slide central axis C of the movable mold, both slide cores do not collide with each other, and bonded to each other only after completion of clamping. Of course, frictional resistance is not generated between the cores 3, 4. After completion of clamping, a primary molten resin is casted into a primary molding space S1 from a first gate to mold a primary molded wall. Thereafter, both slide cores 3, 4 are retreated to the molding positions to release a secondary molding space. Secondary molten resin which is different from the previous molten resin is casted into a secondary molding space from a secondary gate to mold a secondary molded wall.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-color molding die for molding, for example, a part of a peripheral wall of a cartridge case with a different plastic material, and particularly to a pair of dies for defining a molding space. A two-color molding die in which a slide core is provided and both slide cores are in close contact with each other at the time of primary molding.

[0002]

2. Description of the Related Art In a cartridge case such as a disk cartridge or a tape cartridge, a transparent window plate and an opaque case body have been conventionally formed integrally with each other. Japanese Patent Application Laid-Open No. 5-109228 discloses an example. It is. There, the slide core provided on the movable mold side is retracted to form a space for secondary molding. The secondary-formed window plate is formed in a hat-shaped cross-section by a main window portion facing the window opening of the case body and a flange portion overlapping the inner peripheral wall of the window opening.

[0003] Japanese Patent Application Laid-Open No. Hei 5-237873 discloses a cartridge case in which the above-mentioned window plate is inverted inside and outside. There, a portion corresponding to the flange portion of the window plate is exposed on the outer surface of the case body. In the case of such a two-color molded product, a slide core for forming a main window is provided on a movable mold, and a slide core for forming a flange is provided on a fixed mold side. This is because the former slide core alone cannot form a space for secondary molding.

[0004]

As described above, in a two-color molding die in which a slide core is provided in each of a fixed die and a movable die, the two slide cores come into close contact with each other at the time of primary molding, and Next, the molding space will be closed. Depending on the structure of the window plate, the two slide cores may be engaged with each other. In such a molding die, the fixed die is clamped while each slide core is projected into the primary molding space.
Therefore, if the shape accuracy of the two slide cores and the positional accuracy with respect to each mold are insufficient, the two slide cores may collide with each other during mold clamping and damage the mold.

[0005] In order to avoid such a situation, it is necessary to sufficiently improve the shape accuracy and the position accuracy of the slide core, and the cost of the two-color molding die increases accordingly. During molding, it is necessary to perform strict temperature control, which is one of the causes of lowering the operation rate of the molding apparatus. Incidentally, in the molding die disclosed in Japanese Patent Application Laid-Open No. Hei 5-237873, one of the adjacent surfaces of the slide core which is in close contact with the mold at the time of mold clamping is inclined to the inclined surface to reduce the frictional resistance when both slide cores slide. It has been reduced.

When the clearance between the two slide cores is set to be large, the shape and position accuracy of the slide cores do not need to be so advanced, and the collision of the two slide cores at the time of mold clamping can be avoided. However, in this case, the plastic material for the primary molding enters the adjacent gap between the two slide cores, and a so-called “burr” appears. As a result, the adjacent gap between the two slide cores has to be minimized, and as a result, the processing accuracy of the mold has to be sufficient as described above.

An object of the present invention is to eliminate the need for the shape accuracy and position accuracy of the slide cores provided in both the fixed mold and the movable mold to be advanced to the left, and to prevent collision between the slide cores during mold clamping. An object of the present invention is to provide a two-color molding die that can surely prevent the occurrence of burrs and can prevent the generation of burrs by bringing both slide cores into close contact during mold clamping. Another object of the present invention is that the two slide cores can be brought into close contact only after the mold clamping is completed, so that the slide cores can be prevented from colliding with each other during the mold clamping, or relatively sliding with a large frictional resistance. Another object of the present invention is to provide a two-color molding die capable of improving the durability of the die.

[0008]

According to the present invention, there is provided a two-color molding die, in which a secondary molding space S2 is defined in each of a fixed mold 1 and a movable mold 2 defining a primary molding space S1. 1.
Second slide cores 3 and 4 are provided. The slide cores 3 and 4 are arranged so as to protrude into the primary molding space S1 and to be adjacent to each other when the mold is clamped. Both slide cores 3
At least one of the four slide center axes P1 and P2 is slightly inclined with respect to the open / close slide center axis C of the movable mold 2. Specifically, the slide center axes P1 and P2 of the slide cores 3 and 4 are inclined by the same angle with respect to the open / close slide center axis C, and the inclination angle θ is set to 2 degrees or more.

[0009]

[Operation] Slide cores 3 and 4 provided on a pair of molds 1 and 2
Are slightly inclined with respect to the opening / closing slide center axis C of the movable mold 2, so that the slide cores 3 and 4 come into contact with each other until the mold clamping of the movable mold 2 is completed. There is no opportunity. Even when the two slide cores 3 approach each other alternately, there is a gap between the two slide cores 3 and 4 in the direction perpendicular to the opening / closing slide center axis C due to the inclination of the slide center axes P1 and P2. Because it always exists. This gap becomes zero only after the closing of the movable mold 3 is completed, and the two slide cores 3 and 4 are in close contact with each other. Therefore, no burrs occur between the slide cores 3 and 4 during the primary molding.

[0010]

1 to 4 show an embodiment of a two-color molding die according to the present invention. In FIG. 2, the two-color molding die is
It has a fixed mold 1 and a movable mold 2 that slides toward and away from the fixed mold 1, and a primary molding space S 1 is formed between the joining surfaces of the two molds 1 and 2. Fixed mold 1 and movable mold 2
Are the slide cores 3 and 2 that define the secondary molding space S2.
4 are provided. A first gate 5 for injecting the molten resin into the primary molding space S1 and a first gate 5 for injecting the molten resin into the secondary molding space S2 are provided on the inner surface of the fixed mold 1 facing the two molding spaces S1 and S2. A second gate 6 is provided.

Each of the slide cores 3 and 4 has an end protruding into the primary molding space S1 and a retracted position occupying the secondary molding space S2, and receding from the extended position toward the respective molds 1.2. The secondary molding space S2 can slide back and forth between the molding position and the opening position. Specifically, the slide core 3 provided on the fixed mold 1 side slides back and forth between a midway portion of the primary molding space S1 and a molding position where the core end portion retreats from the primary molding space S1. it can. The slide core 4 provided on the movable mold 2 side can reciprocately slide between an advanced position where its end comes into contact with the fixed mold 1 and a molding position where the core end retreats from the primary molding space S1. The second gate 6
The latter is provided facing the advance position of the slide core 4.

As shown in FIG. 3, both slide cores 3 and 4
Are provided in such a manner that the two molds 1 and 2 are in close contact with each other when the molds are clamped. In order to prevent the slide cores 3 and 4 that are in close contact with each other from colliding with each other at the time of mold clamping, or to prevent the two slide cores from strongly rubbing each other,
The slide center axes P1 and P2 of 4 are slightly inclined with respect to the open / close slide center axis C of the movable mold 2.

More specifically, as shown in FIG. 1, the slide center axes P1 and P2 of both slide cores 3 and 4 are inclined by the same angle θ in the same direction with respect to the open / close slide center axis C. The inclination angle θ is set to at least 2 degrees or more so that the slide cores 3 and 4 do not come into contact with each other until the mold clamping of both the dies 1 and 2 is completed.
If the inclination angle θ is less than 2 degrees, both slide cores 3 and 4
It is necessary to improve the shape accuracy and position accuracy of the mold to some extent, and the manufacturing cost of the mold is high. The maximum value of the inclination angle θ is 45 degrees or less, and more preferably 30 degrees or less.
In FIGS. 1 to 4, the inclination angle θ is expressed to be large in order to clarify the inclination state of the slide cores 3 and 4, but the actual inclination angle θ is 2 to 5 degrees.

The two-color molding die configured as described above is
The molding is performed according to the procedure shown in FIGS. FIG.
(A) shows a state in which the mold is being clamped, and the movable mold 2 is slid and joined to the fixed mold 1 with the respective slide cores 3 and 4 projecting to the advanced positions. At this time, the two slide cores 3 and 4 intersect and approach alternately.
Since the four slide center axes P1 and P2 are inclined by an angle θ with respect to the opening and closing slide center axis C of the movable mold, the two slide cores 3 and 4 do not collide, and only after the mold clamping is completed. Both cores 3 and 4 are in close contact. Naturally both cores 3, 4
There is no frictional resistance between them.

After completion of the mold clamping, the first molten resin is injected into the primary molding space S1 from the first gate 5 to form the primary molding wall 7 (see FIG. 3B). Thereafter, the slide cores 3 and 4 are retracted to the molding position to open the secondary molding space S2. Finally, as shown in FIG.
A second molten resin different from the preceding molten resin is injected from the gate 6 into the secondary molding space S2 to form the secondary molding wall 8. The two molds 1 and 2 are cooled in the above state, and the secondary molding wall 8 is cooled.
After solidifying, the mold is opened and the molded product is taken out.

FIG. 5 is a perspective view of the completed two-color molded product. The two-color molding die of the present invention is suitable for molding the upper half of a cartridge case such as a disk cartridge or a tape cartridge. For example, the primary molding wall 7 is formed of an opaque colored resin, and the secondary molding wall is formed. It can be applied to the case where the viewing window is formed by forming 8 from a transparent resin.

In the above embodiment, both slide cores 3 and 4
The inclination angles θ of the slide center axes P1 and P2 of the first and second slide center axes P1 and P2 are matched with each other.
(Or P2) may be simply tilted. However, in this case, a flank which is in close contact with the slide surface of the inclined slide core is formed in parallel with the slide surface on the slide core side which slides in parallel with the opening / closing slide center axis C. The inclination angle θ of the two slide center axes P1 and P2 may be set to different angles, but in this case, the flank is formed on one of the slide cores as described above. The inclination angle θ may be set so as to be inclined in the counterclockwise rotation direction with respect to the opening / closing slide center axis C.

[0018]

According to the two-color molding die of the present invention, at least one of the slide center axes P1 of the slide cores 3, 4 provided in the fixed and movable dies 1, 2, respectively.
(Or P2) is inclined to prevent the slide cores 3, 4 from colliding or strongly rubbing during the clamping of the molds 1, 2, so that the slide cores 3, 4 can be prevented.
It is not necessary to improve the shape accuracy and position accuracy of the mold, and the manufacturing cost of the two-color molding die can be reduced by that much, and the durability during long-term use can be improved. Temperature control during molding does not need to be strict, and the operation efficiency of the injection molding apparatus can be improved by that much, and the production efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a related structure of a pair of slide cores.

FIG. 2 is a schematic sectional view of a two-color molding die.

FIG. 3 is an enlarged sectional view of a portion A in FIG.

FIG. 4 is a sectional view showing a molding procedure.

FIG. 5 is a perspective view showing an example of a two-color molded product.

[Description of Signs] 1 Fixed mold 2 Movable mold 3.4 Slide core S1 Primary molding space S2 Secondary molding space P1 / P2 Slide center axis C Opening / closing slide center axis θ Tilt angle

Claims (2)

[Claims] 1. A fixed mold 1 for defining a primary molding space S1.
And the movable mold 2 are provided with first and second slide cores 3.4 that define a secondary molding space S2.
And at least one of the slide center axes P1 and P2 of the slide cores 3 and 4 is slightly inclined with respect to the opening and closing slide center axis C of the movable mold 2. Mold for color molding. 2. The slide center axes P1 and P2 of both slide cores 3 and 4 are inclined by the same angle with respect to the open / close slide center axis C, and the inclination angle θ is set to 2 degrees or more. Item 2. The two-color molding die according to Item 1.