JPS59227433A - Injection molding machine - Google Patents

Abstract

PURPOSE:To make it possible to obtain high reliability with regard to its strength while preventing the application of high injection pressure to a glass cylinder, by constituting the title machine from such a mechanism that a plastic stock material pre-molded into a solid form is melted under heating and the molten stock material is transferred to an injection cylinder by a feed plunger. CONSTITUTION:One stock material segment 22 fed by a feed apparatus 23 is supplied into a stock material heating cylinder and melted under heating by infrared rays emitted from a filament 9 and reflected rays from a reflective plate 13. In the next step, when the valve 26 provided to a plunger 15 is opened and feed cylinder 19 is operated. Feed plunger 18 is fallen and the molten stock material is extruded to be supplied into an injection cylinder 24. Subsequently, when the valve 26 is closed and the plunger 27 is allowed to advance, the molten stock material is injected into a mold through a nozzle 25. As mentioned above, by pre-molding the stock material into an individual segment by extrusion, the kneading state of the stock material or the dispersing state of a pigment becomes extremely excellent.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a plastic molding machine.

(Structure of conventional example and its problems) A conventional molding machine of this type is constructed as shown in FIG. In Fig. 1, 1 is a hopper for inputting plastic raw materials, 2 is an injection cylinder that melts raw materials and injects the molten raw materials into a mold, and 3 is a band heater provided on the outer periphery of the injection cylinder 2. , 4 is a screw,
5 is a motor, 6 is a speed reducer, and 7 is a drive cylinder for linearly moving the screw 4.

In the above configuration, the rotation of the motor 5 is transmitted to the screw 4 via the reducer 6, the screw 4 rotates,
The raw material supplied from the hopper 1 is sequentially transferred to the front of the injection cylinder 2 by the screw 4. At this time, the raw material is melted or plasticized by the shear heat generated by the rotation of the screw 4 and the heating by the external heater 3, and is accumulated at the front of the injection cylinder 2. Next, the driving cylinder 7 is operated, and the molten raw material is injected from the tip nozzle of the injection cylinder 2 by the advancing screw 4 and into the molding die.

However, in the conventional example configured in this way, the screw 4 performs rotational movement and linear movement in the axial direction, so the structure is complicated and separate drive sources must be provided for both movements. Ta.

Further, the machining of the screw 4 itself is complicated, and it is necessary to provide a check valve or the like (not shown) at its tip.Furthermore, a large number of heaters 3 are arranged around the outer periphery of the injection cylinder 2. There were many disconnection accidents, and with this heater configuration, it took a long time to raise the temperature, and it was necessary to turn on the heater 3 20 to 30 minutes before the start of molding. For this reason, there have been problems such as, for example, the connection and synchronized operation of the molding machine and the assembly line may become a major hindrance.

(Objective of the Invention) The present invention solves the problems of the conventional example, and provides an injection molding machine that enables melting of raw materials in a short time and improves reliability.

(Structure of the Invention) The present invention comprises an infrared lamp in which a filament is arranged in a space between an inner cylinder and an outer cylinder of a double cylinder made of transparent glass, and a reflector provided to surround this infrared lamp. A plastic raw material previously formed into a solid shape such as a cylinder is supplied from the middle of a feed plunger guide cylinder that constitutes a raw material heating cylinder and communicates with this heating cylinder, is heated and melted, and is transferred to an injection cylinder by a feed plunger. After that, it is injected into the mold through a nozzle.

In this way, in the present invention, since infrared rays are used to melt the raw material, the raw material reaches a predetermined temperature and melts in just a few minutes. Therefore, it is easy to restart after molding is interrupted, and it is especially suitable for assembly conveyors. This is advantageous for synchronous operation. Furthermore, by changing the raw material from the conventional granular form to a solid form, it is possible to perform melting with good thermal efficiency, and the plasticization efficiency can be greatly improved. Furthermore, by solidifying the raw materials in advance, the crosstalk of the raw materials and the dispersion of the pigments become uniform, and the quality of the molded product is stabilized.

(Explanation of Examples) Hereinafter, embodiments will be described in detail based on the drawings.

Fig. 2 shows an embodiment of the present invention, where 8 is an inner cylinder made of transparent glass, and 9 is arranged around the outer circumference of this inner cylinder 8 in a coil shape as shown in Fig. 3. 10 is an outer cylinder made of transparent glass that covers the outside of the filament 9. Both ends of the outer cylinder 10 are welded to the inner cylinder 8 with a sealing material 11, and a space 2 is formed between the two ends.
0 is kept in a vacuum or sealed with an inert gas such as nitrogen to isolate it from air. The filament 9 is held so as not to come into contact with the inner cylinder 8 and the outer cylinder 1O, and its drawn-out portion is sealed with a sealing material 12. The infrared lamp is configured with the above structure. 13 is a connecting plate J provided on the inner surface of 4
L: A reflector surrounding the infrared lamp, which directs all the light emitted by the infrared lamp inward. Note that a cooling water channel (not shown) is provided on the back surface thereof. A raw material heating cylinder is composed of an infrared lamp and a reflector. One end of the inner cylinder 8 is engaged with and supported by a metal flange 15 and the other end is engaged with a base plate 16, and one end of the inner cylinder 8 is connected to a feed plunger guide cylinder 17. A feed plunger 18 is driven by a feed cylinder 19, and is guided by the guide cylinder 17 and inserted into and removed from the inner cylinder 8.

Reference numeral 21 denotes a guide rail for the individual pieces of plastic raw material 22. The individual pieces of raw material 22 are previously formed into solid cylinders, are sent by a feeding device 23 from a parts feeder (not shown), and are fed from the middle of the feed plunger guide cylinder 17. The raw material is supplied into the heating cylinder (inner cylinder 8).

24 is an injection cylinder equipped with an injection nozzle 25 at its tip, and is connected to the raw material heating cylinder via an on-off valve 26. 27 is a plunger that moves linearly within the injection cylinder 24, and 28 is a heat-retaining heater.

Next, the operation of one cycle of this embodiment will be explained.

First, one of the raw material pieces 22 sent by the feeding device 23 is supplied into the raw material heating cylinder, and the filament 9
The raw material is rapidly heated and melted by the infrared light emitted by the infrared light and the reflected light from the reflection plate 13.

Next, open the valve 26 provided on the flange 15, and
When cylinder I9 is operated, feed plunger I8
falls, and the molten raw material is pushed out and supplied into the injection cylinder 24. Then, when the valve 26 is closed and the plunger 27 is advanced, the molten raw material is injected through the nozzle 25 into the mold. After injection is completed or during injection, the raw material for the next shot is supplied into the heating cylinder and heated and melted.

(Effects of the Invention) As explained above, according to the present invention, since the raw material is heated and melted by irradiating infrared rays from the outside of the transparent glass cylinder, the raw material melting time is shorter than that of the conventional screw and band heater methods. In this way, there are fewer heater breakage accidents. Further, by providing the injection cylinder and the raw material melting cylinder separately, high injection pressure is not applied to the glass cylinder, and high reliability in terms of strength can be obtained. Furthermore, by forming the raw material into individual pieces by extrusion or the like in advance, the cross-contact state of the raw material and the dispersion state of the pigment become extremely good.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional in-line screw set injection device, FIG. 2 is a block diagram of an embodiment of the present invention, and FIG. 3 is a cross-sectional view of the heating and melting section of FIG. 2. 8...Inner cylinder, 9...Filament, 10.
...Outer tube, 13...Reflector, 17...Feed plunger guide tube, 18...Feed plunger, 21...Guide rail, 22...Single raw material piece, 23...Feeding device, 24...injection cylinder,
25... Nozzle, 26... Valve, 27...
Plunger. Patent applicant: Matsushita Electric Industrial Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] A filament is placed in the space between the inner and outer cylinders of a double cylinder made of transparent glass, and the space is evacuated or filled with inert gas to form an infrared lamp. a raw material heating cylinder whose outer periphery is surrounded by a reflective plate, and means for supplying plastic raw material previously formed into a solid shape such as a cylinder into the raw material heating cylinder from the middle of a feed plunger guide cylinder that communicates with one end of the inner cylinder. An injection molding machine comprising: a feed plunger that pushes out the raw material melted by the heating cylinder; and an injection cylinder that receives the extruded molten raw material and injects it from a nozzle into a molding die.