JPS6140126A - Injection molding nozzle - Google Patents

Abstract

PURPOSE:To reduce mold manufacturing cost and equipment cost, simplify corresponding treatment when impurities are mingled and improve the appearance of product by providing a heater-builtin torpedo on the injection molding nozzle. CONSTITUTION:An injection molding nozzle body 21 has a base member 22 in the form of a nearly round shaft and a tapering cylindrical head member 24, the back of which is put around the front part of the base member 22 through the screw part 23a. Further, a cylindrical torpedo mount 22a projecting into the space 26 is installed at the front end of the base member 22. The cylindrical torpedo 28 is installed detachably in this mount 22a as the back end of the cylindrical torpedo 28 is screwed into the screw part 23d inside the mount 22a. This torpedo 28 is provided with a heater 29 inside the outward projecting part 28a. This cord 29a is connected from the torpedo mount 22a of the base member 22 to external power souce through the cord pulling up hold 30.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to an injection molding nozzle used for injecting molten plastic molding material into a mold in plastic injection molding.

Conventional technology In general, injection molding involves a molding machine main body (
The fixed mold (2) is attached to the fixed side mounting plate (1a) of 1), and the movable side mounting plate (1) is moved toward and away from the fixed side mounting plate (1a) along the guide point (3). 1b)
A movable mold (4) equipped with a guide pin (4a) is attached to the nozzle (6) equipped with a band heater (5).
Attach it to the injection machine <7>, join both molds (2) and (4), and insert the nozzle (6) into the cavity (8) formed between them.
This is done by injecting a more molten plastic molding material, cooling and assimilating it, and then retracting the movable mold (4) to take out the product (9).

Therefore, if the solidified material in the injection path from the sprue in contact with the nozzle (6) to the gate of the cavity (8) is integrally formed as a runner (10) on the product (9), it will be necessary to remove it later. Therefore, conventionally, a runnerless system as shown in FIG. 5, for example, has been adopted. This method uses a small hole-shaped pin gate (tla) to
) A sprue bush (12) having a sump part (11) communicating with the spool bush (11) is covered with a band heater (13) surrounding the spool part (11), and this sprue bush (12) is attached to the identification side mold (2). Mounting bolts (14) (14)
The nozzle (6) is brought into contact with the opening edge of the mold reservoir (11), and the molten plastic molding material (15) is injected into the cavity (8) through the mold reservoir (11). It is something. Note that (16) is a cooling fluid flow hole. In other words, in this method, the hot water tank (11)
The inner material (15) remains in a molten state, and the cooled and solidified product (9) is separated at the pin gate (11a), so that the runner (10) is not formed.

One point that the invention attempts to solve is that while the conventional runnerless method has the advantage of not producing a runner (10), it requires the assembly of a sprue bush (12) for each stationary mold (2). In order to form the assembly part, complicated processing must be performed on the mold (2), which results in very high production costs, and the use of sprue bushes (12) and band heaters (13) significantly increases equipment costs. rise to Further, if impurities are mixed into the material (15) and the bin gate (11a) is closed, it is necessary to remove the entire mold (2) from the molding machine body (1) and disassemble it. Furthermore, since the sprue bush (12) is heated by the pan heater (13), the product (9) is cooled on the inner end surface (12a) of the sprue bush (12), especially around the pin gate (11a'). The problem is that the product (9) tends to have a pattern on its surface due to a delay in solidification, resulting in poor appearance.

Means for Solving the Problems The present invention provides an injection molding nozzle with a new configuration equipped with a torpedo with a built-in heater, so that it can be applied to the mold (2) of the conventional sprue bush (12) and band heater (13). Runner-less injection method that eliminates the need for assembling, dramatically reduces mold production costs and equipment costs, simplifies the process to deal with contamination with impurities, and prevents appearance defects due to delayed partial solidification of the product. The purpose is to provide a molding means.

According to the present invention, a torpedo is removably attached to the nozzle body and protrudes outward from the inside of the nozzle body by concentrically penetrating the nozzle opening, and a heater is built in the outwardly protruding part of the torpedo. The gist of the invention is an injection molding nozzle characterized by the following characteristics.

Example The present invention will be explained below based on illustrated embodiments.

In Fig. 1, (21) is an injection molding nozzle body, which includes a substantially circular base member (22) and a rear part externally fitted to the front part of this base member (22) via a threaded part (23a). A tapered cylindrical head member (24) is screwed onto the rear end of the base member (22) through a screw portion (23b), and a screw portion (24) for attaching the injection machine (7) to the rear end is screwed onto the rear portion of the base member (22). It is composed of three removable members, including a mounting member (25) with a mounting member (23c).

Therefore, the front part of the head member (20 has an inner space (26)
A nozzle opening (27) communicating between the base member (22) and the outside is provided, and a cylindrical torpedo attachment portion (22a) that protrudes into the space (26) is provided at the front end of the base member (22). 22a) has a cylindrical shaft-shaped torpedo (28).
attaches its rear end to the threaded part (23d) on the inner surface of the mounting part (22a).
), the nozzle port (27) is screwed into the main body (21) so as to concentrically penetrate through the nozzle port (27) and protrude outward. This torpedo (28) has a heater (29) loaded inside the outward protrusion (28a), and the cord (29a) is connected to the base member (22).
It is configured to be connected to an external power source through a cord lead-out hole (30) communicating from the torpedo mounting portion (22a,) to the side surface. The front end of the torpedo (28) preferably has a conical shape with a bin gate insertion protrusion (31) protruding from the top as shown in the figure, but in some cases it may be a conical shape without the protrusion (31). There is no problem even if it is in a state.

On the other hand, the base member (22) has a connection that communicates with the space (26) at the front end side and communicates with the space (32) formed between the mounting member (25) and the base member (22) at the rear end side. Holes (33) (33)... are bored so as to be equally distributed in the circumferential direction as shown in Fig. 2, and the mounting member (25)...
) has an introduction hole (34) bored along the axis that communicates with the space (32) and is open on the rear end surface, and the plastic molding material (15) molten from the injection machine (7) is inserted into the introduction hole. (34) → Space (32> → Communication hole (33) (3
3) The liquid flows in the order of space (26) and flows out from the annular nozzle port (27). Note that a band heater (5) is attached to the outer circumferential surface of the nozzle body (21) in the same manner as a conventional general commercially available nozzle (6).

When using the injection molding nozzle of I14 composition, as shown in FIG. 3, it is possible to use one simply provided with a quenching part (11) as the stationary side mold (2). That is, the outward protrusion (28a) of the torpedo (28) of the nozzle is inserted into the sump (11), the pin gate insertion protrusion (31) is fitted into the bin gate (11a), and the sump is inserted into the sump (11). The nozzle opening (21) of the nozzle is attached to the opening edge of (11).
) By pressing the peripheral edge, the plastic molding material (15) flowing out from the nozzle opening (27) flows into the sump (
11) Injected into the cavity (8) through the annular gap between the inner surface and the outer surface of the torpedo (28) and the gap between the pin gate (fta) and the pin gate insertion protrusion (31).

But no hot water! II (11) d, 15 is maintained in a molten state by heating with the heater (29) built into the torpedo (28), and the cooled and solidified product (9) is separated at the bin gate (11a), so there is no runner. injection molding becomes possible. In addition, in the above configuration, the hot water tank (
Even if some degree of assimilation occurs within Torpedo (28)
The vicinity of one surface of is maintained in a molten state by the heat of the heater (29), and a flow gap for the material (15) is secured, so the cooling fluid flow holes <16) <16> are placed near the immersion part (11). It is also possible to speed up the assimilation of the product (9) and improve the molding efficiency. Furthermore, if impurities get mixed into the material (15), there is no need to disassemble the mold (2), and the problem can be dealt with by simply attaching and detaching the nozzle.

Effects of Invention □ The injection molding nozzle according to the present invention has a torpedo with a built-in heater attached to the nozzle body, so by using this nozzle, there is no fixed side metal plate as in the past in runnerless injection molding. Since there is no need to assemble a sprue bush and a band heater to the mold, and the mold only needs to be provided with a sump, the mold manufacturing cost and equipment cost are significantly reduced compared to conventional methods. It is possible to completely prevent the occurrence of patterns due to the cooling delay around the bin gate of the product, which was difficult to avoid using this method, and it is possible to provide a product with a good appearance.In addition, the position of the cooling fluid is placed close to the sump, which improves molding efficiency. It can also be raised. Furthermore, if there is impurity in the molding material, there is no need to remove and disassemble the mold as in the conventional case, and the problem can be dealt with simply by attaching and detaching the nozzle. Furthermore, since the torpedo is removable, even if the length of the column sump differs depending on the type of mold, only the torpedo needs to be replaced with one of the corresponding length, and the nozzle body can be shared.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional side view of an injection molding nozzle according to the present invention, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is a main part showing an injection molding operation using the same nozzle. FIG. 4 is a schematic side view showing a general example of an injection molding apparatus, and FIG. 5 is a longitudinal side view of main parts showing a conventional runnerless injection molding operation. (21)... Nozzle body, (27)... Nozzle mouth,
(28)...Torpedo, (28a)...Outward protrusion, (29)...Heater. Above/Above Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] An injection molding nozzle in which a torpedo is removably attached to a nozzle body and protrudes outward by concentrically passing through a nozzle opening from the inside of the nozzle body, and a heater is built into the outwardly protruding part of the torpedo.