JPH0310018Y2 - - Google Patents

Description

[Detailed description of the invention] "Industrial field of application" This invention is applied to the first screw (first stage) in the horizontal plasticizing cylinder of the screw type pre-plastic injection device.
In contrast, the present invention relates to a two-stage injection molding machine in which a dedicated motor is directly connected to the second screw (second stage) to facilitate vaporization of moisture and volatile matter harmful to molding generated between the second screw and the vertical cylinder.

``Prior Art'' A screw-type pre-plastic injection device has a heating cylinder arranged at a predetermined angle with respect to an injection plunger.The screw feeds the material in the hopper into the heating cylinder, and the material is plasticized. It becomes molten and is fed into the injection plunger.

It is well known that the injection amount is measured by the amount of retreat of the injection plunger, and after measurement, the injection plunger moves forward to inject into the mold.

However, although the above-mentioned injection molding machine in which the two sets of cylinders are formed at a required angle is suitable for large machines with large injection capacity and injection pressure, small injection molding machines have a small diameter of the injection plunger, so it is difficult to adjust the inclination angle. It is very difficult to provide this because it is mechanically complicated.

In particular, since there are bends in the flow path of the molten resin, there is a good chance that the molten resin will accumulate in the joints between both cylinders in small machines, and it will take a lot of time to change the material (color change) and the material for cleaning. is necessary.

Furthermore, if a vent is formed in the horizontal plasticizing cylinder to discharge moisture and volatile matter in the molten resin to the outside, since it is a small machine, there is a risk that it will overflow from the vent and flow out to the outside.

``Problems to be Solved by the Invention'' The present invention was made in view of these problems, and includes a screw plastic injection device in which a horizontal plasticizing cylinder is disposed above and a required distance is formed between the cylinder and the cylinder. A horizontal injection cylinder is disposed below the upper and lower cylinders, and a vertical cylinder is provided that connects the upper and lower cylinders.
The first objective is to remove moisture and volatile matter from plasticized molten resin by arranging screws, and also to make it easy to change materials (color changes). This is the second purpose.

"Means for Solving the Problems" The present invention takes the following technical means to solve the above problems.

In a screw plastic plastic injection device, a second screw directly connected to a motor is disposed within a vertical cylinder provided perpendicularly to the front axial direction of a horizontal plasticizing cylinder of the injection device, and a second screw is provided approximately between the vertical cylinder and a bearing box. A cylindrical intermediate member is provided, a space is formed between an inner wall of the intermediate member and the second screw, a vent hole communicating with the space is formed in a side wall of the intermediate member, and the vent hole is connected to the vent hole. A discharge pipe is provided, and the molten resin deaerated through the vent hole and the discharge pipe is caused to descend into the injection cylinder by the second screw.

"Operation" When the molten resin plasticized by the horizontal plasticizing cylinder is supplied from the first screw into the second screw, it descends while being guided by the rotating second screw.

At that time, moisture and volatile matter generated from the molten resin rise due to the special shape of the second screw,
When it reaches the space, it can be discharged to the outside through a vent hole through a discharge pipe, or it can be forcibly sucked outside by a vacuum pump and discharged.

"Example" A preferred example of the present invention will be explained below based on the drawings.

Figure 1 is a longitudinal sectional view of the two-stage injection molding machine of the present invention.
FIG. 2 is a longitudinal sectional front view of the main part within the two-dot diagonal line in FIG.

Reference numeral 10 denotes a horizontal plasticizing cylinder disposed horizontally above the screw plastic injection device, and a first screw 11 for kneading and forwarding the molding material is built into the cylinder.
A speed reduction mechanism 12 and a motor 13 are provided at the rear end, and the tip of the first screw 11 faces a side wall opening 15 of a vertical cylinder 14 provided perpendicularly to the front axial direction of the horizontal plasticizing cylinder 10.

Reference numeral 16 denotes an external heater provided on the outer periphery of the horizontal plasticizing cylinder 10 in order to knead and plasticize the molding material supplied from the hopper 17 in conjunction with the heat generation effect of the first screw 11.

As shown in FIG. 2, the vertical cylinder 16 has a built-in second screw 18 via a bearing 19 for further kneading and quantitatively discharging the molten resin plasticized by the first screw 11.

Reference numeral 34 denotes a bearing box containing a bearing 19 that supports the second screw 18, and the lower end surface 35 of the bearing box 34 is connected to the upper part of the approximately cylindrical intermediate member 36 disposed on the upper end surface 141 of the vertical cylinder 14. It is supported by an end surface 361.

Since the inner wall of the through hole 362 formed in the intermediate member 36 is larger than the second screw 18 as shown in the figure, the vertical cylinder 14
A space 32 is necessarily formed above the side wall opening 15 of.

A vent hole 363 is provided in the space 32 in the intermediate member 3.
It is formed on the side wall of 6.

A base end of the discharge pipe 20 is connected to the vent hole 363, and a vacuum pump 21 is provided at the rear end of the pipe 20 as required.

364 is a heat dissipation blade (fin) formed on the outer periphery of the intermediate member 36. Furthermore, a speed reduction mechanism 23 and a motor 24 are provided at the upper end of the second screw 18. Said second screw 1
The tip of 8 is the upper wall opening 2 of the horizontal injection cylinder 25.
facing 6.

27 is an external heater provided on the outer periphery of the vertical cylinder 14.

The horizontal injection cylinder 25 is arranged parallel to the horizontal plasticizing cylinder 10 at a required distance, and injects the molten resin plasticized by the first screw 11 and the second screw 18 into the mold. An injection plunger 28 is built in, and an injection piston 29 is provided at the rear of the injection plunger 28.

30 is a measuring chamber for measuring the molten resin injected through the upper wall opening 26 of the horizontal injection cylinder 25 provided with an external heater 22; The injection plunger 28 is thus retracted.

After metering, the injection plunger 28 moves forward to inject from the nozzle 31 into the mold.

"Effect of the invention" The first plasticizing cylinder and the injection cylinder are arranged parallel and horizontally, and a second vertical cylinder is connected between both cylinders, and the molten resin is disposed in the second vertical cylinder. When the moisture and volatile content in the resin rises at the same time as it is uniformly mixed, it enters the space formed between the inner wall of the through hole of the cylindrical intermediate member and the second screw, and the vent hole and the vent that communicate with the outside. It is discharged to the outside through the discharge pipe connected to the hole, and when the vacuum pump is activated as necessary, it can be forcibly discharged to the outside by the suction action, so that it is injected into the injection plunger. The molten resin contains no harmful gases.

Therefore, the molten resin injected from the injection plunger into the mold is degassed, so that the mold is not corroded and the appearance of the molded product, that is, uneven color, is eliminated.

Furthermore, since there is no stagnation of molten resin, material changes (color changes) can be easily performed.

[Brief explanation of the drawing]

Figure 1 is a longitudinal sectional view of the two-stage injection molding machine of the present invention.
FIG. 2 is a longitudinal sectional front view of the main part within the two-dot diagonal line in FIG. 10... Horizontal plasticizing cylinder, 11... First screw, 14... Vertical cylinder, 15... Side wall opening, 18... Second screw, 20... Exhaust pipe, 21... Vacuum pump, 25... ...Horizontal injection cylinder, 32...Space, 363...Vent hole.

Claims (1)

[Scope of utility model registration request] In a screw plastic injection device, a second screw 18 directly connected to a motor is disposed within a vertical cylinder 14 provided at right angles to the front axial direction of a horizontal plasticizing cylinder 10 of the injection device.
A substantially cylindrical intermediate member 36 is disposed between the intermediate member 36 and the bearing box 34, a space 32 is formed between the inner wall of the intermediate member 36 and the second screw 18, and a vent hole 363 communicating with the space 32 is provided. is formed in the side wall of the intermediate member 36, and the vent hole 36 is
3, and the molten resin deaerated through the vent hole 363 and the discharge pipe 20 is caused to descend into the injection cylinder 25 by the second screw 18. Two-stage injection molding machine.