JPS59129129A - Nozzle device of injection molding machine - Google Patents

Abstract

PURPOSE:To obtain a nozzle device for injection molding machine, which is capable of regulating the mixing and dispersing conditions of materials by changing the cross section of a flow path for the materials, by using a system in which the aperture between the conical projection of a cylinder and the conical recession of the cylinder head is regulated by the axially directed movement of the cylinder head. CONSTITUTION:The female screw 21 of a cylinder head 19 is screwed onto the male screw 13 of a cylinder 12, and slackening and loosening between the female screw 21 and the male screw 13 are prevented by a lock nut 22. A flow path 23 for materials is formed between the conical projection 15 of the cylinder 12 and the conical recession 18 of the cylinder head 19. The lock nut 22 is loosened, and the cylinder head 19 is turned and moved in the axial direction, to regulate the aperture delta in the flow path 23 for materials.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a nozzle device for an injection molding machine used for injection molding of crosslinkable polymer materials such as thermoplastic resins or rubber.

FIG. 1 shows an example of a conventional movable injection device.

This conventional injection device melts and injects resin by the following actions. The material input from the hopper 1 is transferred to the left in FIG. 1 inside the heating cylinder 4 by the screw 3 which is rotationally driven by the screw drive device 2.
During this time, the material is gradually melted by heating by the heater and internal heat generated by the rotation of the screw 3. cylinder 4
As the molten material is accumulated at the tip of the cylinder 4, the screw 3 is pushed back to the right in FIG. 1, and a predetermined amount of molten material is accumulated at the tip of the cylinder 4. When a predetermined amount of molten material has accumulated, hydraulic oil is sent to the injection cylinder 5,
This causes the screw 3 to move toward the tip of the cylinder 4. Therefore, the molten material at the tip of the cylinder 4 is injected into a mold (not shown) through the nozzle 6, and a molded product having a predetermined shape is obtained.

However, when using the above-mentioned injection device to mold materials mixed with pigments such as dry colors and master patches, if the kneading action of the screw is not sufficient, the pigments will not be dispersed properly, resulting in poor molding. may occur. To solve this problem, a nozzle device with a mixing function is used. Conventional nozzle devices are shown in FIGS. 2 to 4, respectively. The nozzle arrangement shown in FIG. 2 is of the type with a torpedo 7, the nozzle arrangement shown in FIG. 3 is of the type with color dispersion plugs 8 and 8', and the nozzle arrangement shown in FIG. This type has a static mixer 9. All of the above types of nozzle devices improve the merging and dispersion performance by passing the molten material accumulated at the tip of the screw or plunger through a narrow gap when injecting it.

However, in such conventional nozzle devices, the constant α
Only the kneading/dispersing performance could be obtained, and if it was necessary to change the kneading/dispersing performance, it was necessary to change the equipment. That is, it was necessary to change the shape, dimensions, etc. of the torpedo, color dispersion plug, and static mixer. For this reason, there are problems in that a long working time is required to replace parts, resulting in poor efficiency, and the need to prepare parts of various shapes increases the cost of the device.

The present invention has been made by focusing on the above-mentioned problems in the nozzle devices of conventional injection molding machines. It is an object of the present invention to solve the above-mentioned problems by making it possible to easily adjust the gap between the flow paths by moving the cylinder head in the axial direction.

Hereinafter, the present invention will be explained based on FIG. 5 of the accompanying drawings showing an embodiment thereof.

First, the configuration will be explained.

At the tip of the cylinder 12 housing the screw 11, a male threaded portion 13, a cylindrical portion 14, and a conical convex portion 15 are formed in order toward the tip. A passage hole 16 communicating with the inner diameter portion of the cylinder 12 communicates with the surface of the conical convex portion 15 through a passage hole 17. A cylinder head 19 having a conical recess 18 corresponding to the conical protrusion 15 is attached to the tip of the cylinder 12 . The cylinder head 19 is aligned by fitting the hole 20 continuous from the large diameter part of the conical recess 18 into the cylindrical part 14 of the cylinder 12, and screwing the female threaded part 21 into the male threaded part 13 of the cylinder head 12. It is fixed to the cylinder 12 by. In addition, #It thread part 1
A lock nut 22 is provided to prevent loosening between the lock nut 3 and the female threaded portion 21. A material flow path 23 is formed between the conical convex portion 15 of the cylinder 12 and the conical concave portion 18 of the cylinder head 19. A nozzle 25 having a passage hole 24 communicating with the material flow path 23 is attached to the tip of the cylinder head 19 by a screw on its outer periphery. Heaters 26 and 27 are provided on the outer periphery of the cylinder 12.
is provided, and a heater 28 is provided on the outer periphery of the cylinder head 19.

Next, the effect will be explained.

The material plasticized and melted and accumulated by the screw 11 is kept warm by the heaters 26, 27 and 28, and then flows through the passage hole 16, the passage hole 17, the material flow path 23, and the passage hole 24.
The material is extruded through the tube and filled into a mold (not shown). The molten material is subjected to a large shearing action as it passes through the narrow material flow path 23, and the pigment contained in the material is sufficiently divided into fractions. Therefore, we can print and print stable, high-quality molded products.
can be done. When the molding material or the pigment used is changed, the gap δ of the material flow path 23 can be easily reset to the most appropriate value accordingly. That is, if the lock nut 22 is loosened and the cylinder head 19 is rotated, the cylinder head 19 will move in the axial direction, so the lock nut 22 may be tightened when the gap δ in the material flow path 23 reaches a desired value. Therefore, the gap δ between the material flow paths 23 can be easily adjusted without disassembling the device.

Note that when the gap δ in the material flow path 23 is made smaller, the pressure loss when the material passes increases, and this pressure loss becomes thermal energy, so the material temperature rises rapidly. For this reason, the ability to fill the mold with material in the case of thin-walled molded products is improved. Furthermore, if the mold is filled at the same material temperature, the temperature of the molten material accumulated in the cylinder can be lowered, so discoloration, burning, etc. due to material retention can be prevented.

The above explanation was for the case where thermoplastic resin was used as the material, but the nozzle device of the index molding machine according to the present invention is suitable for molding materials that involve a thermal crosslinking reaction such as rubber. can also have great effects. When injection molding rubber, usually 10
Accumulate the material at a temperature below 0°C and add it to 180″
The material is injected and filled into a mold heated to about 0.0° C. to cause a thermal crosslinking reaction. In this case, since the molded article is gradually heated by heat transfer from the mold to the material, a considerably long time is required until the thermal crosslinking reaction is completely completed. For this reason, molding of rubber requires a longer time than molding of normal thermoplastic resin. However, when injection molding of rubber material is performed using the nozzle device of the injection molding machine according to the present invention, the material passes through a narrow material flow path just before being filled into the mold, and at that time, the temperature of the material increases significantly. ” - rise. Therefore, the thermal crosslinking reaction is completed within a short time. According to test results in which rubber material was injected using the nozzle device of an injection molding machine according to the present invention, the temperature of the rubber material maintained at about 100°C in the cylinder was 150 to 160°C immediately before entering the mold. The temperature had risen to C. As a result, the thermal crosslinking reaction is 1
It was possible to complete the process within 1/2 to 1/3 of the time. This greatly increases productivity. In addition, since the fluidity, hardness, etc. of rubber materials generally vary significantly depending on the material composition, it is necessary to adjust the size of the aperture during injection according to the material. By using the device, the gap δ of the material flow path 23 can be easily adjusted, so that the rubber material can be molded under optimal molding conditions.

As described above, according to the present invention, a material flow path is formed between the conical convex portion formed at the cylinder tip and the conical concave portion formed in the cylinder head assembled to the cylinder tip, and the cylinder Since the head can be fixed at a desired axial position relative to the cylinder, the cross-sectional area of the material flow path can be easily adjusted.
The effect is that it is possible to provide optimal kneading and dispersion performance depending on the properties of the material.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional rotary injection device, FIG. 2 is a sectional view of a conventional nozzle device, FIG. 3 is a sectional view of a conventional nozzle device, and FIG. 4 is a sectional view of a conventional nozzle device. FIG. 5 is a sectional view of a nozzle assembly according to an embodiment of the present invention. 11...φ screw, 12φ... cylinder, 13...
kll: Threaded portion, 14... Cylindrical portion, 15. Fist/conical convex portion, 16... Passage hole, 17... Passage hole, 18.
... Conical recess, 19... Cylinder head, 20.
e. Hole, 21. Female screw part, 22. Lock nut, 23. Material flow path, 24. Passage hole, 25. Bone nozzle, 26. 27, 28. 1 Heater.

Claims (1)

[Claims] A material flow path is formed between a conical protrusion formed at the cylinder tip and a conical recess formed in the cylinder head assembled to the cylinder tip, and the cylinder head moves in the desired axial direction with respect to the cylinder. Injection molding machine nozzle device that can be fixed in position.