JPH0139327B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an injection molding method and apparatus suitable for injection molding two or more types of plastic materials.

In multicolor molding, dissimilar material molding, multilayer molding, etc. in injection molding processes, at least two or more materials are melted in separate plasticizing injection units and injected into the cavity. Since the composition of the materials in the molded products is different, they are usually molded using an injection molding machine for multicolor molding and an injection molding machine for multilayer molding, respectively. In this way, the conventional method is intended to be used as a dedicated machine, so if both are required at the same time, they must be installed separately and exclusively, which requires a large space and increases equipment costs. There were disadvantages such as high cost.

Figure 1 shows the molding state in a normal two-color injection molding machine as an example of the conventional method of multi-color injection molding, in which materials of different colors are placed in separate plasticizing injection devices 1 and 1a. The state is shown in which the material is plasticized and melted by heating cylinders 2, 2a and screws 3, 3a, and then injected and filled into separate cavities 4, 4a, respectively. That is, in two-color injection molding, the passages 5 and 5a that communicate the plasticizing injection devices 1 and 1a and the cavities 4 and 4a are independent from each other.

When injecting, after injecting one resin from one plasticizing injection device 1 into one cavity 4 having half the required volume, only the movable mold 6 is rotated 180 degrees around the axis 7. Next, the other resin is injected from the other plasticizing injection device into the cavity 4a, which is half filled with the injected resin. 8 is a fixed mold, 9 is a fixed plate, 10 is a movable plate, 11 is a column, 12 is a rotating device for the movable mold 6, and 13 is a mold clamping device.

On the other hand, to explain an example of two-layer molding as an example of multi-layer molding in FIG.
a and cavity 4 of molds 6a and 8a for two-layer molding
The passages 5, 5a communicating with the cavity 4a are arranged concentrically in the middle and communicate with the cavity 4a. In this device, first, the material of the plasticizing injection device 1 communicating with the outer circumferential circular passage is injected into the cavity 4a to the extent that it does not become full, and then the material of the plasticizing injection device 1a is injected to the tip inside the cavity 4a. Inject into the resin that has been placed to form a two-layer molded product.

As shown in FIGS. 1 and 2, at present, two-color injection molding and two-layer injection molding are manufactured and used as dedicated injection molding machines for each. In other words, although there are two systems of plasticizing injection equipment for both two-color injection molding and two-layer injection molding, the uses, purposes, functions, and structures differ depending on the form of the communication passage with the mold cavity. However, it was not possible to perform both two-color molding and two-layer molding with one molding machine.

In view of these drawbacks, the present invention aims to provide a multi-purpose injection molding machine that enables multicolor molding, dissimilar material molding, multilayer molding, etc. to be performed using the same injection molding machine. In other words, the mold clamping device and plasticizing injection device are common for both two-color injection molding and two-layer injection molding, and by freely selecting and switching the communication passage between the plasticizing injection device and the mold cavity, two-color injection molding is possible. This allows for molding or two-layer injection molding.

Next, the present invention will be explained with reference to an embodiment shown in the drawings.

FIG. 3 shows the state during two-color injection molding, in which the hot runner manifold 16 is fixed on the plasticizing injection device 1, 1a side of the fixed plate 9, and the resin passage 21 in the hot runner manifold 16, 21
Rotary type switching valves 19, 19a are provided in part a so as to be rotatable through 90 degrees in forward and reverse directions. On one side of the hot runner manifold 16 are heating cylinders 2, 2.
Plasticizing injection devices 1 and 1a consisting of screws 3 and 3a were connected to passages 21 and 21a and were integrally attached. Nozzles 14 and 14a provided on the side of the hot runner manifold 16 facing the fixed mold 8 are provided so as to be able to press the corresponding resin injection ports of the fixed mold 8 for two-color molding. 4,4a
is a cavity similar to that shown in Fig. 1, 5,
5a is a passage, 6 is a movable mold, 7 is a shaft, 8 is a fixed mold, 9 is a fixed plate, 10 is a movable plate, and 12 is a rotation device that rotates the movable mold 6 by 180 degrees with the shaft 7 as the rotation axis. be.

Further, inside the hot runner manifold 16, there are 22,
22a, and a double nozzle 15 for two-layer injection molding was provided at a portion of the axial center of the hot runner manifold 16 that could press the fixed mold 8a for two-layer molding. Of course, by switching the switching valves 19, 19a, the passages 21, 21a can be made to communicate with the nozzles 14, 14a as shown in FIG. 3, or with the passages 22, 22a as shown in FIG. It's becoming like that.

When performing two-color injection molding, the switching valves 19, 19a are switched to the state shown in FIG. 3, and the plasticizing injection devices 1, 1a are communicated with the two-color injection molding nozzles 14, 14a. Then, resin is injected into the small cavity 4 from one plasticizing injection device 1, and after rotating the movable mold 6 by 180 degrees, another resin is injected into the remaining part of the cavity 4a from the plasticizing injection device 1a. .

When carrying out two-layer injection molding, as shown in FIG. It is communicated with a nozzle 15 for layer forming. The resin injected from the two plasticizing injection devices 1 and 1a passes through a hot runner manifold 16 and is sent to a nozzle 15 that is in pressure contact with the mold 8a. When injecting the resin stored in the heating cylinders 2, 2a of the plasticizing injection devices 1, 1a, first, one screw 3 is advanced and the cavity 4 is injected.
The outer periphery of the molded product is roughly molded within the cavity 4b, and then the screw 3a is moved forward and the next resin is injected into the resin that was previously injected into the cavity 4b to mold the inside of the molded product. Then, a two-layer injection molded product is formed.

In this way, in this invention, the middle of the resin passage that communicates the plurality of plasticizing injection devices and the mold cavity is divided into a multicolor molding passage and a multilayer molding passage,
Because the choice can be made freely, the same plasticizing injection device can be used for both multicolor molding and multilayer molding, allowing it to be used for multiple purposes. In addition, we can expand applications, reduce equipment, and reduce equipment costs.
It is useful because it has many effects such as reducing the installation space and shortening the setup changeover time from multi-color to multi-layer or vice versa. Furthermore, according to the present invention, by sequentially using any of a plurality of plasticizing injection devices, it is possible to instantly switch colors instead of replacing them, and it is possible to reduce material loss, etc. It also has useful effects.

[Brief explanation of drawings]

Figures 1 and 2 respectively show conventional examples similar to the present invention. Figure 1 is a horizontal longitudinal sectional view showing the case of two-color molding, and Figure 2 is a vertical longitudinal sectional view showing the case of two-layer molding. , 3 and 4 show one embodiment of the apparatus for carrying out the method of the present invention, and FIG.
FIG. 4 is a horizontal longitudinal sectional view showing the case of color molding, and FIG. 4 is a horizontal longitudinal sectional view showing the case of two-layer molding. 1, 1a...Plasticization injection device, 2, 2a...Heating cylinder, 3, 3a...Screw, 4, 4a,
4b...Cavity, 5, 5a, 21, 21a,
22, 22a... passage, 6, 6a... movable mold,
7... Shaft, 8, 8a... Fixed mold, 9... Fixed plate, 10... Movable plate, 12... Rotating device, 14,
14a, 15... Nozzle, 16... Hot runner manifold, 19, 19a... Switching valve.

Claims (1)

[Scope of Claims] 1. A plurality of types of plasticizing materials are plasticized by different plasticizing injection devices, and among passages communicating between each plasticizing injection device and a mold cavity, mutually independent multi-color molding devices are used. An injection molding method in which either a channel or a multilayer molding channel in which each channel is arranged on the same axis is selected for injection molding. 2. The passageway that communicates the plurality of plasticizing injection devices and the cavity of the mold is composed of a plurality of mutually independent multicolor molding passageways and a multilayer molding passageway in which each passageway is arranged on the same axis. This is an injection molding machine equipped with a hot runner manifold on the fixed plate that allows you to select either of the two passages.