JPH1086181A - Injection nozzle structure for injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a product failure or quality degradation of the product by preventing stringing of molten resin in a nozzle bush runner due to an end of a mold slug well in a sprue at the time of releasing of a molding molded by an injection molding means, preventing generation of a stringy matter, and hence obviating adherence of the matter to a surface of the molding. SOLUTION: In a nozzle bush 21 in which a nozzle bush runner 24 and a sprue 27 connected to the runner 24 are formed on an axis of the bush 21, a plate-like chip 29 formed of a metal thin plate having satisfactory thermal conductivity and high rigidity is positioned at a boundary between the sprue 27 and the runner 24 so that a surface of the chip 29 becomes parallel to an axial direction with the sprue 27, and installed fixedly in a radial direction of the sprue 27.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection nozzle structure in an injection molding apparatus used for molding a resin molded article, and more particularly to a resin molding after a molten resin is injected from a nozzle bush into a cavity. The present invention relates to a nozzle bush that can eliminate a stringing phenomenon caused by a molten resin when an article is released from a mold.

[0002]

2. Description of the Related Art A schematic structure of a conventional injection molding apparatus used for injection-molding a resin molded product, particularly in the vicinity of an injection nozzle, is as shown in FIG.
Is a core mold corresponding to the cavity mold 1. A nozzle bush 5 having a nozzle bush runner 3 and a sprue 4 communicating with the nozzle bush runner 3 is attached to the cavity mold 1. The nozzle bush runner 3 is The main runner 8 and the branch runner 7 provided in the hot runner block 6 communicate with a resin extruder (not shown).

Reference numeral 9 denotes a band heater attached to the outer periphery of the nozzle bush 5, 10 denotes a cold runner formed by closing the cavity mold 1 and the core mold 2, and
Numeral 11 indicates the gate and numeral 12 indicates the cavity.

In order to perform injection molding of a resin molded product by the injection molding apparatus having such a configuration, the molten resin fed from the resin extruder is supplied to the main runner 8, the branch runner 7, the nozzle bush runner 3, and the sprue 4 by using the same. Cold runner 10 sequentially formed by cavity mold 1 and core mold 2
The molten resin injected into the cold runner 10 is further injected (pressurized) into the cavity 12 through the gate 11.

After the molten resin is injected into the cavity 12, cooling is performed at a certain timing, and then both the cavity mold 1 and the core mold 2 are opened to release the molded product.

[0006]

When the molded article molded in the cavity is taken out of the mold after molding the resin molded article by such an injection molding procedure, first, the cavity mold 1 and the nozzle bush 5 are cored together. The mold is opened from the mold 2 and then the molded product attached to the cavity mold 1 is released from the cavity mold 1 and taken out. As shown in FIG. The wells 14A and 14B are integrally released. This molded product 13 and cold slug well 14
A, 14B, when the nozzle bush runner 3
Because the resin in the molten state is maintained,
The molten resin in the nozzle bush runner 3 is attached to the tip of the cold slug well 14A in the sprue 4 which is detached from the inside of the sprue 4, so that the cold slug well 14A in the sprue 4
Is drawn out of the sprue 4, the molten resin is drawn out in a thread form by the tip of the cold slug well 14 </ b> A, and a stringing object 15 is generated.

[0007] Thus, when the molded article 13 is released from the mold, the string 15 pulled out in a thread form at the tip of the cold slug well 14A is easily adhered to the surface of the molded article 13 and solidified. There was a defect that the product of the molded article 13 was defective or the product quality was impaired.

The present invention has been made in view of such a problem, and when the molded product formed by the injection molding means is released from the mold, the molten resin in the nozzle bush runner by the tip of the cold slug well in the sprue is formed into a thread. To prevent the occurrence of stringing and prevent the threading from adhering to the surface of the molded product, thereby preventing product defects or product quality deterioration. It is an object of the present invention to provide a nozzle bush of an injection molding apparatus that can perform the injection molding.

[0009]

According to a first aspect of the present invention, there is provided an injection molding method in which a nozzle bush runner is formed on an axis of a nozzle bush, and a sprue is formed following the nozzle bush runner. In the nozzle structure of the molding apparatus, at the boundary between the sprue and the nozzle bush runner, a plate tip having good thermal conductivity is positioned so that the plate surface of the plate tip is parallel to the axial direction of the sprue; The sprue is characterized in that it is a nozzle bush that is erected and fixed in the diameter direction of the sprue.

According to a second aspect of the present invention, in addition to the first aspect, the plate-shaped tip is a nozzle bush which is mounted and fixed in a plurality of radial directions from the center axis position of the sprue.

In claim 3, claim 1 or claim 2
In addition, the present invention is characterized in that the plate-shaped chip is a nozzle bush in which the edge on the nozzle bush runner side is formed as a knife edge.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a nozzle bush according to the present invention will be described below in detail with reference to FIGS.

The nozzle bush 21 provided in the injection molding apparatus comprises a first bushing member 22 and a second bushing member 23. The first bushing member 22 has an internal axial direction. Nozzle bush runner 2
4 is formed at the lower end of the nozzle bush runner 24, and a female screw 25 for connecting the second bush component 23 is formed. Reference numeral 26 denotes a band heater attached to the outer peripheral surface of the first bushing member 22.

A tapered sprue 27 whose diameter is widened from the upper end to the lower end is formed in the inner axial direction of the second bush constituting member 23, and the nozzle bush is formed at the upper end of the sprue 27. Runner 24
The opening 28 is formed to have an opening diameter equal to the opening diameter. At the boundary between the opening 28 and the sprue 27, for example, a plate-like chip 29 formed of a metal plate having excellent thermal conductivity and high rigidity is fixed in position in the diameter direction of the sprue 27, Moreover, the direction of the plate surface of the plate-shaped chip 29 is regulated so as to be parallel to the axial direction of the sprue 27. Further, the second bush component 2
On the outer periphery of the upper end of 3, an external thread 30 screwed to the internal thread 25 formed on the first bushing member 22 is formed.

As described above, in the nozzle bush 21 of the present embodiment, the first bush member 22 and the second bush member 23 are connected on the same axis by screwing the female screw 25 and the male screw 30. However, the reason why the first bush component 22 and the second bush component 23 are assembled is that the sprue 27 is provided at the boundary between the nozzle bush runner 24 and the sprue 27 of the nozzle bush 21. Plate chip 29 straddling in the diameter direction
This is for the purpose of facilitating the mounting process. Therefore, unless the nozzle bush runner 24 has a short or long mounting workability, it is necessary to press the nozzle bush 21 in order to mount the plate-like chip 29 straddling the sprue 27 diametrical direction at the boundary. It is not necessary to form the bush component 22 and the second bush component 23 in an assembled configuration.

As described above, at the boundary between the nozzle bush runner 24 formed inside the nozzle bush 21 and the sprue 27, a plate-like chip made of a thin metal plate having good thermal conductivity and high rigidity is provided. 29 is fixed so that its plate surface is parallel to the axial direction of the nozzle bush runner 24 and the sprue 27. Therefore, this plate-shaped chip 29 allows the heat of the high-temperature nozzle bush runner 24 to escape to the low-temperature cavity mold at the boundary between the nozzle bush runner 24 and the sprue 27 during the operation of the injection molding apparatus. When the molded product is released after the injection of the resin, the molten resin in the nozzle bush runner 24 that is in contact with the tip of the cold slug well formed in the sprue 27 is cooled by the plate-shaped chip 29. Therefore, the degree of stringing of the molten resin in the nozzle bush runner 24 at the tip of the cold slug well at the time of release from the mold is suppressed to an extremely low level.

[0017] Therefore, it is possible to prevent the generation of a long stringing material due to the molten resin drawn out by the tip of the cold slug well as in the prior art, whereby the threading material adheres to the surface of the molded product, and the quality of the molded product is reduced. This can prevent problems such as lowering the quality and causing defective products.

In the above-described embodiment, the above-mentioned plate-like chip 29 is described as a single piece that is installed in the diameter direction of the sprue 27. However, the present invention is not limited to this. A plurality may be provided so as to form a triangular shape or a cross shape in a more radial direction. It is desirable that the plate-like chip 29 be an extremely thin plate in order to reduce the injection resistance of the molten resin. In order to further reduce the injection resistance, the edge of the plate-like chip 29 on the side of the nozzle bush runner 24 is knife-cut. It may be formed in an edge shape.

[0019]

As described above, according to the present invention, when a molded article injection molded by an injection molding apparatus is released,
Since the tip of the cold slug well integrated with the molded product suppresses the occurrence of stringing material that is drawn out in a molten resin thread, the stringing material is attached to the surface of the molded product. This can be prevented beforehand, and deterioration of the quality of the molded product or occurrence of defective products can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a first bush component according to the present invention.

FIG. 2 is a sectional view showing an embodiment of a second bush component according to the present invention.

FIG. 3 is a plan view showing an embodiment of a second bush constituting member according to the present invention.

FIG. 4 is a sectional view showing an embodiment of a nozzle bush according to the present invention.

FIG. 5 is a partial view of a main part of a conventional injection molding apparatus.

FIG. 6 is an explanatory view of a main part of a molded article molded by a conventional injection molding apparatus.

[Description of Signs] 21 ... Nozzle bush 22 ... First bush constituent member 23 ... Second bush constituent member 24 ... Nozzle bush runner 25 ... Female screw 26 ... Band heater 27 ... Sprue 28 ... Opening 29 ... Plate chip 30 … Male screw

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuma Kinase 628 Kumeda, Yoshimi-cho, Hiki-gun, Saitama Prefecture KS Engineering Co., Ltd.

Claims (3)

[Claims] 1. A nozzle structure of an injection molding apparatus comprising a nozzle bush runner (24) formed on an axis of a nozzle bush (21) and a sprue (27) following the nozzle bush runner (24). The above sprue (2
At the boundary between 7) and the nozzle bush runner (24),
A plate-like chip (29) having good thermal conductivity is positioned such that the plate surface of the plate-like chip is parallel to the axial direction of the sprue (27), and is bridged and fixed in the diameter direction of the sprue (27). An injection nozzle structure of an injection molding apparatus, characterized by being subjected to a rush. 2. The plate-like chip (29) is provided with a sprue (2).
2. The injection nozzle structure of an injection molding apparatus according to claim 1, wherein a plurality of the nozzles are formed in a radial direction from the center axis position of (7). 3. The injection nozzle structure of an injection molding apparatus according to claim 1, wherein the edge of the plate-shaped chip (29) on the side of the nozzle bush runner (24) is formed as a knife edge.