JPS5996931A - Multiple molding method - Google Patents

Abstract

PURPOSE:To prevent the leakage of a resin completely by backing a nozzle within a range in which the nozzle and a hot runner are not separated before a mold opening after an injection is completed, decompressing the inside of the hot runner and opening a mold while moving the nozzle. CONSTITUTION:At a proper time until the mold opening is started after the injection is completed, the nozzles 13 is backed, substantial volume in the hot runner 9 is expanded, and the resin pressure of the raw material resin 16 in the runner 9 is decompressed. A movable core plate 2 and a cavity plate 3 are moved by fixed quantities, and the cavity plate 3 and core plates 1, 2 on both sides are separated mutually while shapes 17, 17... are released from cores 5, 5... by stripper plates 15, 15. In this case, an injection cylinder 12 follows up the movement of the cavity plate 3 and is moved, and the nozzle 13 is left as it is under the state in which it is fitted to the hot runner 9.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot-launch type multiple molding method and an apparatus therefor, which can sandwich cavity plates and mold on both sides.

In recent years, from the perspective of improving molding efficiency, multiple molding methods that allow molding on both sides of the cavity plate have attracted attention.
Some of them are being put into practical use.

This multiple molding can be roughly divided into two types: a cold launch method in which the resin in the runner is also cooled and solidified each time molding is performed, and a hot runner method in which the runner is constantly heated and only the molded product is taken out.

Of these, the former has been in practical use for a relatively long time, but the opening and closing strokes of the mold are long to take out the launch part, and considering the dots on the runner part, the latter
That is, the hot runner method is more desirable.

This hot runner method multiple molding method can be further classified as follows:
The type in which the injection direction and the mold clamping direction intersect, as described in Japanese Patent Publication No. 51-20546, and the type described in Japanese Patent Publication No. 51-2
As described in Japanese Patent No. 5408, the injection direction and the mold clamping direction are in the same direction, but in the former, the injection direction and the mold clamping direction intersect, so the arrangement of the devices is T-shaped or L-shaped. shape, allowing for a larger installation area.

However, since the nozzle is brought into direct contact with the cavity plate, the hot runner section can be shortened and the resin temperature in the hot runner section can be easily controlled, but this method does not meet market needs.

On the other hand, the latter, that is, one in which the injection direction and the mold clamping direction are in the same direction, requires almost no changes to the currently mainstream engineering injection molding machines, and only requires replacing the mold, so it is not practical. is the most desirable format, but in order to use this format, the cavity plate sandwiched between the core plates must be connected to the injection nozzle using a hot runner, and the cavity must be inserted into the cavity by penetrating the core plate in some way. The plate and nozzle must be connected, conventionally e.g.
(2) A hole as described in Japanese Patent Publication No. 51-25408, which passes through the cavity plate and nozzle so as to be movable relative to the fixed core plate, and has a length that allows opening and closing of the mold.

Connected via a tranner device. Or ■ Jitsukaisho 55
As described in Japanese Patent No. 163120, the cavity plate and the nozzle are connected by a hot runner device attached to a fixed core plate, and a hot runner block that fits into the hot runner bush is provided in the cavity plate, and the block A mold that allows opening and closing of the mold.

Further, there has been proposed a structure in which the injection nozzle extends through a fixed core plate and comes into contact with a cavity plate, as described in ■N Publication No. 56-33620, but the above-mentioned ■, In the device (2), the hot runner passes through the fixed core plate, making it long and making it difficult to control the temperature of the hot runner.

However, in the device (2) above, the nozzle and the cavity plate are in direct contact, so if resin leaks at this contact surface, molten resin will flow between the cavity plate and the core plate and repair will be impossible. In addition to being difficult, if molding (mold clamping) is performed without being aware of this resin leakage, there are problems such as damage to the mold, and both are not completely satisfactory.

The present invention has been made in view of the above, and includes forming a nozzle attached to the tip of an injection cylinder into a cylindrical shape, and slidably fitting the nozzle and a hot runner formed in a cavity plate into each other. After the injection is completed and before the mold opens, the nozzle is moved back to the extent that the nozzle and hot runner do not separate, and after depressurizing the inside of the hot runner, the hot runner, nozzle, and pot are synchronized with the movement of the cavity plate to keep them in the bottom position. By opening the mold while moving the nozzle, the above-mentioned conventional problems are solved.

The following will explain the embodiments shown in the drawings.

1 is a fixed core plate attached to a fixed platen (not shown); 2 is a movable core plate attached to a movable platen (not shown); 3 is a cavity plate disposed between the core plates 1.2; The fixed core plate 1 and the movable core plate 2 are connected to each other by a connecting rod 4.4.

5.5... is a core attached to the core plate 1.2, and the cavity plate 3 facing the core 5.5... has cavities 6.6...・・・
... is formed.

7 is a hot runner pro mounting hole formed in the cavity plate 3;
8 is provided.

9 is a hot runner bored in the hot runner block 8, and one end of the runner 8 has a hot tip of 10°10...
It is connected to the cavity 6.6 through..., and the other end is inserted into the nozzle insertion hole 11 drilled in the center of the cavity plate from one side with an 8-inch hot runner block. It is connected to a nozzle 13 attached to the tip of an injection cylinder 12 of an injection molding machine.

The nozzle 13 is formed into a cylindrical shape so as to fit tightly into the hot runner 9, and has a labyrinth groove 14 on its outer peripheral surface.
14... are provided.

Still, the cylindrical portion of the nozzle 13 has a sufficient length to completely seal the resin from flowing out from the hot runner, and the nozzle 13 and the hot runner are connected by an advancing/retracting device (not shown) of the injection molding machine. The amount of engagement with the block 8 is controlled, the resin pressure in the hot runner 9 is reduced after injection is completed, and the nozzle 13 is moved to follow the movement of the cavity plate 3 when the mold is opened, so that the nozzle 13 is constantly engaged with the hot lunch. To prevent resin leakage from the fitting portion of the hot runner 9 and nozzle 13 and to prevent hot chips 1 from molding when the molded product is released,
This prevents so-called stringing, where the resin leaking from the nozzle of 0.10 adheres to the molded product. 15.
15 is the core plate 1.2 and the cavity plate 3
A stripper plate is disposed between the stripper plate, 16 is a raw resin in a molten state, and 17° is a molded product.

This invention has the configuration as described above. Next, its effect will be explained.

The state shown in FIG. 2 shows the state in which the mold is clamped by a mold clamping device (not shown), the injection molding machine is operated, and the molten raw resin is injected from the nozzle 13 to injection mold the molded products 17, 17... So, molded product 17.17...
Cool until the shape is fixed.

At an appropriate time between the completion of this injection and the start of mold opening, the advancing/retracting device (not shown) of the injection molding machine is activated, and the fourth and fifth
As shown in the enlarged view in the figure, the hot runner 9 and the nozzle 13 are fitted together from the state shown in FIG. The raw resin 16 in the runner 9 is
Reduce the resin pressure.

Next, the mold clamping device (not shown) is activated to move the movable core plate 2 and the cavity plate 3 by predetermined distances (normally, the amount of movement between the movable core plate and the cavity plate is 2:1) as shown in FIG. The cavity plate 3 and the core plates 1.2 on both sides of the cavity plate 3 are separated from each other, and the molded product 17 is separated by a stripper plate (15.15).
．． 17 is released from the core 5.5.

At this time, the injection lidder 12 (nozzle 13) moves following the movement of the capacity plate 3, and the nozzle 13 remains fitted into the hot runner 9.

When the mold release is completed in the above steps, the mold is clamped again and the molding is repeated in the same steps as above.

As described above, according to the present invention, the hot runner installed on the cavity plate and the nozzle attached to the tip of the injection nozzle are always fitted into each other, and resin leakage between them can be completely prevented. By using a long hot runner, the injection cylinder (nozzle) can pass through the fixed core plate and be directly connected to the cavity plate without having to protrude or open the end of the runner to the outside of the fixed core plate. Temperature control is easy, and since the connection part with the hole tray/suto nozzle can be completely closed, no resin leakage occurs from that part.

Furthermore, since the pressure inside the hot runner is reduced after injection, it is possible to prevent the molten resin from flowing out from the hot tip nozzle during mold release, so-called stringing, which prevents molten resin from adhering to the molded product, resulting in clean molding. It has advantages such as being moldable.

[Brief explanation of the drawing]

1 to 4 show embodiments of the present invention.
The figure is a front view, Fig. 2 is a plan sectional view showing the mold clamped state, Fig. 3 is a plan sectional view showing the mold open state, and Fig. 4 shows the fitted state of the hot runner and nozzle in the mold clamping state. FIG. 5 is an enlarged sectional view showing the fitted state in the open state of the same mold. 1: Fixed core plate 2: Movable core plate 3: Cavity plate 9: Hot runner 12: Injection cylinder 13: Nozzle procedure amendment (method) March 16, 1981 Kazuo Wakasugi, Commissioner of the Patent Office 1, of the case Indication Patent Application No. 57-206,899 2, Name of the invention Multiple molding method 3, Relationship with the case of the person making the amendment Patent applicant address No. 2, No. 1, Otemachi 2, Chiyoda-ku, Tokyo Name (210) ) Sumitomo Heavy Industries, Ltd. Representative Tsunezo Nishimura 4, Agent address 6, Sumitomo Heavy Industries, Ltd., 2-2-1 Otemachi, Chiyoda-ku, Tokyo, Subject of amendment Attached drawing 7, Amendment Content

Claims (1)

[Claims] 1) A nozzle attached to the tip of the injection cylinder is formed into a cylindrical shape, and the nozzle is slidable through a fixed core plate into a hot runner of a cavity plate that is attached to the plate so as to be able to reciprocate. At the same time, after injection is completed and before the mold is opened, the nozzle is moved back within a range where the nozzle and hot runner do not separate, and after the inside of the hot runner is depressurized, the hot runner and nozzle are held in the fitted state. A multiple molding method characterized by opening the mold while moving the nozzle in synchronization with the movement of the capacity plate.