JPS60915A - Injection molding machine - Google Patents

Abstract

PURPOSE:To improve the rise time and thermal efficiency by shortening the melting time of raw material by a method wherein raw plastic material, which is shaped in individual pieces such as cylindrical columns or the like in advance, is inserted in a metal cylinder and molten by heating through the irradiation of infrared rays on said cylinder from its outside. CONSTITUTION:Cylindrical raw material tablets 13 are sequentially supplied from a parts feeder 22 and housed in a magazine 17 and reached a discharge part 17b by the rotation of the magazine 17 and finally inserted in a metal cylinder 8 by means of a plunger 23. In a heating cylinder, the infrared light emitted from infrared lamps 10 and its reflected light reflected by a reflector 11, both of which a glass tube 9 transmits, quickly heat the air in a space formed between between the glass tube 9 and the cylinder 8 and simultaneously heat the cylinder 8, resulting in quickly melting the raw material in order to inject the molten raw material through a nozzle 14 into a molding die. EFFECT:The re-starting after the interruption of molding is facilitated and few disconnection accident also occurs and at the same time no dust problem develops.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a resin injection 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 an injection cylinder 2.
4 is a screw, 5 is a band heater provided on the outer periphery of
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, and 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 molten FJ+ or plasticized by the shear heat generated by the rotation of the screw 4 and heating by the external heater 3, and is accumulated in the front part 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, since the screw 4 performs rotational movement and linear movement in the axial direction,
The movement was complicated, and it was necessary to provide separate drive sources for both movements. In addition, with this heater configuration, it takes a long time to raise the temperature, so
The heater 3 must be energized and heated 30 minutes beforehand, which can cause major problems, such as when connecting the molding machine and the assembly line or when operating them in synchronization. There was a point.

(Objective of the Invention) The present invention solves the problems of the conventional examples described above, and provides an injection molding machine that allows raw materials to be melted in a short time and is suitable for molding precision parts.

(Structure of the Invention) In the present invention, an infrared heater is arranged around a relatively thin metal cylinder, and the outside of the infrared heater is surrounded by a reflecting plate to constitute a raw material heating cylinder. Plastic raw material molded into individual pieces is inserted, heated and melted, and then injected into a mold.

In this way, in the present invention, infrared rays are used to melt the raw material, so the raw material reaches a predetermined temperature and melts in just a few minutes. Therefore, the start-up time until the molding UIJ can be started is shortened, and it is easy to restart the molding after interruption, which is particularly advantageous for synchronized operation with the assembly conveyor. Furthermore, by changing the raw material from the conventional granular form to individual pieces such as cylinders, thermal efficiency is increased and plasticization efficiency is greatly improved. Furthermore, by forming the powder into individual pieces in advance, the kneading of the raw materials and the dispersion of the pigment become much better.

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

FIG. 2 shows an embodiment of the present invention, in which 8 is a relatively thin metal cylinder, and 9 is a transparent glass tube such as quartz glass coaxially arranged outside the metal cylinder 8. , 10 is a plurality of rod-shaped infrared lamps (heaters) arranged around the glass tube 9 in parallel to the axis of the metal cylinder 8; 11 is the metal cylinder 8;
A reflecting plate is provided to surround the outside of the infrared lamp 10 with the axis of the infrared lamp 10 as the center.
1 and point it toward the center. 12 is a holding plate that holds one end of the metal cylinder 8; 15 is a holding plate that holds the other end;
Both end portions of the reflecting plate 11 and each infrared lamp 10 are fixedly held by the holding plates 12 and 15, respectively.

A nozzle plate 1- having a nozzle 14 is provided at the tip of the metal cylinder 8. 16 is a heater for keeping the nozzle warm. The raw material heating and injection cylinder is thus constructed.

Reference numeral 13 designates cylindrical raw material tablets 1 to 1 having a certain size, which are formed in advance by extrusion molding or the like, and are fed to a predetermined position by a guide rail 19 from a parts feeder 22, as shown in FIG. , raw material feed cylinder 2
0 into the magazine 17 one by one. 18 is the piston guide of the feed cylinder 2o, and the magazine 1
It is installed so that the storage hole of the raw material tablet receiving part 17a of No. 7 and the center position coincide with each other. The magazine 17 rotates intermittently and has a raw material tablet receiving section 17a and a discharging section 17b.
The JC charge tablets 1-13 (which have the following characteristics and are stored in the storage hole of the receiving portion 17a) are sequentially fed and spread by the rotation of the magazine 17 and reach the Ml: mountain portion 17b.

A plunger 23 is driven by a drive cylinder 26 to push out the powder tablet 13 that has reached the discharge portion 17b of the magazine 17 and insert it into the metal cylinder 8.

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

First, the raw material tablets 13 sent from the parts feeder 22 are sequentially stored in the magazine 17, and the tablets 1:3 that have reached the ejection part 17b by rotation of the magazine 17 are inserted into the metal cylinder 8 by the plunger 23. In the heating cylinder, the infrared light emitted from the infrared lamp 10 and the reflected light from the reflection plate 11 pass through the glass tube 9 and rapidly move the air in the space between the glass tube 9 and the metal cylinder 8. At the same time, the metal cylinder 8 is also heated, and the raw material inside the cylinder is rapidly melted. After the raw material has melted and spread out, the plunger 23 moves forward and the molten raw material is injected into the molding die through the nozzle 14.

The plunger 23 first moves forward to a predetermined position when inserting the raw material tablet, and here the stepped portion 24 hits the stopper 25 and stops.Next, after the raw material tablet is heated and melted, the stopper 25 rises and the plunger 23 advances further and the molten raw material is injected.

Although this embodiment has the above-described configuration, a two-stage cylinder may be used as the drive cylinder.

After injection and pressure retention are completed, the plunger 23 is moved back to its original position, the magazine 17 is sent one station, and the above operation is repeated again.

In this embodiment configured as described above, since the relatively thin metal cylinder is heated from the outside with an infrared lamp,
The raw material inside the cylinder can be melted in a very short time.

As the infrared heater placed outside the metal cylinder, various types of infrared heaters can be used in addition to a rod-shaped lamp.

FIG. 5 shows a second embodiment of the present invention, in which several ring-shaped infrared heaters 28 are arranged coaxially with the metal cylinder 8 on the outside of the glass tube 9. It is something. Note that the same reference numerals as in FIG. 2 represent the same parts or members of the same type (the same applies hereinafter).

Also in this configuration, the air between the metal cylinder 8 and the glass tube 9 can be heated instantaneously, and the plastic raw material inside the cylinder 8 can be melted in a short time by using radiant heat. In addition, since the heating section is divided into a plurality of zones by the ring-shaped infrared heater 28, the temperature can be controlled for each zone, and the temperature of the molten raw material can be controlled with high precision.

Note that a single spiral infrared heater (lamp) may be used instead of the ring-shaped infrared heater.

FIG. 6 shows a third embodiment of the invention.

A transparent glass tube 9 made of quartz glass or the like is used as an inner cylinder, a transparent glass tube 30 is provided on the outside thereof as an outer cylinder, and a coiled filament 31 made of tungsten or the like is arranged between the inner cylinder and the outer cylinder. do. The filament 31 is an inner cylinder,
It is held so as not to contact the outer cylinder, and the space between the inner cylinder and the outer cylinder is completely sealed by the sealing material 32 and the sealing material 33 of the ficimen 1 to the drawer part. The space is kept in a vacuum or filled with an inert gas such as nitrogen. In this way, an infrared lamp surrounding the metal cylinder 8 is constructed.

The operation of one cycle of this embodiment is exactly the same as that of the first embodiment.

(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 metal cylinder,
Compared to conventional screw and band heater methods, the raw material melting time is shorter, and therefore restarting after interruption of molding is easier. Also, there are fewer heater disconnection accidents.

On the other hand, since the raw materials are solidified in advance by extrusion molding, etc., the kneading of the raw materials and the dispersion of pigments are good, and there is no problem of dust that occurs when using granular raw materials, making it ideal for precision molding that dislikes dust. It's advantageous.

[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 a first embodiment of the present invention, and FIG.
The figures are a cross-sectional view of the heating and melting section in Figure 2, Figure 4 is a diagram showing the raw material tablef 1 to storage magazine, Figure 5 is a configuration diagram of the second embodiment of the present invention, and Figure 6 is a diagram showing the storage magazine. , is a configuration diagram of a third embodiment of the present invention. 8... Gold J2T [J cylinder, 9... Transparent glass tube, 10... Rod-shaped infrared lamp, 11...
Reflector plate, 13... Raw material tablets 1 to 14, Nozzle, 17... Magazine, 19... Guide rail, 20... Feed cylinder, 22... Parts feeder, 23... Plunger , 26...
Drive cylinder, 28... Ring-shaped infrared heater,
30... Glass tube, 31... Filament. Patent applicant: Matsushita Electric Industrial Co., Ltd. Figure 1 Figure 3 Figure 2 Figure 4 Figure 2 Figure 5 Figure 6

Claims (3)

[Claims] (1) A means for sequentially inserting plastic raw materials previously formed into individual pieces such as cylinders into storage holes of an intermittently rotating magazine, and a plunger for pushing out the plastic raw materials stored in the other side of the magazine. and a raw material heating and injection cylinder that heats and melts the extruded plastic raw material and injects it into the molding die through a nozzle.
An injection molding machine characterized in that a glass tube is coaxially provided on the outside of a metal cylinder, an infrared heater is placed on the outside of the glass tube, and the outside of the glass tube is further surrounded by a reflecting plate. (2) The infrared heater comprises a plurality of rod-shaped or ring-shaped infrared heaters, or one or more spiral-shaped infrared heaters arranged outside the glass tube. Injection molding machine as described in section. (3) The infrared heater has the glass tube as an inner tube and a glass outer tube on the outside thereof, and a filament is arranged in the space between the inner tube and the outer tube, and the space is sealed to create a vacuum. Claim No. 1 is characterized in that the lamp comprises an infrared lamp filled with an inert gas or an inert gas.
Injection molding machine described in ).