JP2778007B2 - Injection molding method of molded article provided with insert and its mold - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an injection molding method capable of easily molding a molded article having a bendable insert by a resin pressure injected into a cavity, and a mold for the injection molding. About.

(Prior Art) Generally, for example, when molding a molded product P having a thin and long insert M as shown in FIG. 5 (a), a fixed mold of a mold as shown in FIG. 5 (b) Plate Ka and movable side plate
If the resin is filled from the gate G after inserting the insert M into the cavity C formed by Kb, there is an inconvenience that the insert is bent as shown by a chain line due to the pressure of the resin because the insert is long and thin.

Therefore, conventionally, as one injection molding method, as shown in FIG. 6 (a), first, a semi-molded product Pa in which the insert M is fixed by a primary molding die is formed, and the insert is fixed. After that, this semi-molded product Pa is
As shown in (2), the resin is charged from the gate G1 after being put into the cavity C1 of another secondary molding die. K1 is a fixed-side template, and K2 is a movable-side template.

(Problems to be Solved by the Invention) In the conventional method, molding is divided into a primary mold and a secondary mold, and molding is performed using separate molds. Further, there is a problem that the equipment cost is increased by using separate molds.

An object of the present invention is to suppress the increase in equipment cost,
The purpose is to enable efficient molding.

(Means for Solving the Problems) A feature of the injection molding method of a molded article provided with the insert of the present invention is that one cavity 13 formed by the fixed mold plate 1, the movable mold plate 2 and the core 12 is provided. 1st opening and closing nozzle 10
And a first gate 14 communicating with the opening / closing nozzle, and a second gate communicating with the second opening / closing nozzle 11 and the second opening / closing nozzle.
In the method of injection molding using a hot runner mold having a mold 15, first, the fixed mold plate 1 and the movable mold plate 2 are separated from each other, and the insert M is supported by the core to form the cavity. A step of joining the movable mold plate to the fixed mold plate after being inserted at a predetermined position in the core 13; and moving the core 12 in one direction by a distance d to form a first cavity in one side of the insert. A space 13a is formed, and the first opening / closing nozzle 10 and the first gate 14 communicating therewith are opened,
A step in which the core 12 closes the second opening / closing nozzle 11 and the second gate 15 communicating therewith;
A step of injecting liquid resin from the first gate 14 into the first cavity space 13a formed on one side of the insert, and then moving the core 12 in the other direction by a distance d, A step of opening the second gate 15 and forming a second cavity space 13b on the other side of the insert in the cavity; and opening the second opening / closing nozzle 11 and setting the second gate 15 A step of injecting a liquid resin into the two-cavity space 13b and cooling and solidifying the resin.

Further, a feature of the mold for injection molding of a molded article provided with the insert according to the present invention is that the mold includes a hot runner mold and an insert M inserted into the cavity 13 of the mold. The mold has one cavity 13 formed by the fixed mold plate 1, the movable mold plate 2 and the core 12.
A first opening / closing nozzle 10 for the cavity and a first gate 14 communicating with the opening / closing nozzle, and a second opening / closing nozzle 11 for the cavity and a second gate 15 communicating with the second opening / closing nozzle. Wherein the core is capable of reciprocating a predetermined distance d in the cavity,
In addition, the insert M can be supported at a predetermined position, and when the core moves in one direction, a first cavity space is formed on one side of the insert in the cavity, and the first gate is open. The core is configured such that the second gate is closed, and when the core moves in the other direction, a second cavity space is formed in the cavity on the other side of the insert, and the first gate is The second gate is configured to be opened in a closed state.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

First, a hot runner mold for injection molding will be described, and then an injection molding method will be described.

As shown in FIG. 1, of the fixed-side mold plate 1 and the movable-side mold plate 2 forming a parting line on the contact surface, the fixed-side mold plate 1 located on the upper side is a fixed-side mounting plate. 3 is attached. A hot runner block 4 is provided inside each of the fixed mold plate 1 and the fixed mounting plate 3. A sprue bush 5 is formed at the upper center of the hot runner block 4, and an injection nozzle is located above the sprue bush. The sprue 6 in the sprue bush 5 is connected to the first and second opening / closing nozzles 1 of the gate portions 8 and 9 provided on both lower sides of the hot runner block from the runner 7 provided in the hot runner block 4.
It communicates with runners 7a and 7b that reach the parting line. Each of the opening and closing nozzles 10 and 11 can be opened and closed using a cold valve.

A cavity 13 is formed between the fixed mold plate 1 and the movable mold plate 2 and the core 12 between the fixed mold plate 1 and the movable mold plate 2. The cavity 13 is the runner 7 on the left as shown in FIGS.
A first gate 14 leading to a is connected to the runner 7 on the right.
It communicates with the second gate 15 which communicates with b. The upper surface of the core 2 forms the bottom surface of the cavity 13 and has a function of supporting the insert M in the cavity. core
The plate 12 is fixed to the tip of a pin 17 projecting from the plate 16, and the plate 16 is movable by the operation of the cylinder 18. The plate 16 has a spring 22 in a space surrounded by a back plate 19 disposed on the back of the movable mold plate 2 and a spacer block 21 between the back plate and the movable mounting plate 20.
It is movably arranged in opposition to. Therefore, when the cylinder 18 is actuated, the pin 17 moves up and down, so that the core 12 reciprocates by the maximum movement distance d, and the reciprocation increases or decreases the volume of the cavity 13, and in the example of FIG. By moving the first cavity space 13a, the first cavity space 13a having the minimum volume is formed. The core 12 has a function of opening and closing the second gate 15 opened in the cavity 13, and closes the second gate in the state shown in FIG. 1 and opens it in the state shown in FIG.

Next, an injection molding method for a molded article having an insert will be described with reference to FIGS.

First, the movable mold plate 2 is separated from the fixed mold plate 1 by retreating the movable mount plate 20, and is inserted into the cavity 13 with the thin and long insert M placed on the upper surface of the core 12. . Then, the movable-side mounting plate 20 is advanced to join the fixed-side template 1 to the movable-side template 2. At this time, the insert M is positioned in the cavity 13 by the core 12. Therefore, the cylinder 18 is operated to move the core 12 constituting the cavity 13 upward by the maximum movement distance d. At this time, the volume of this cavity is small, leaving only the upper space (first cavity space 13a) above the insert M in the cavity 13. At this time, the first opening / closing nozzle 10 and the first gate 14 communicating therewith are open, and at the same time, the second gate 15 communicating with the second opening / closing nozzle is closed on the side surface of the core 12.

Then, when the liquid resin is filled from the injection nozzle through the sprue 6, as shown in FIG.
It is injected from 7a through the first gate 14 into the first cavity space 13a of the cavity 13. At this time, the liquid resin is
Since the gate 15 is closed, it does not flow into the runner 7b.

After a predetermined time has elapsed after the completion of the injection, when the core 12 is moved downward by the distance d as shown in FIG. 2, the second cavity space 13b is formed in the lower half of the cavity 13, that is, below the insert M. It is formed. At this time, the second open / close nozzle 1
The second gate 15 communicating with 1 is opened. Then the third
As shown in the figure, when the second opening / closing nozzle 11 is opened and the injection of the resin is started, the second cavity space 13b is filled with the liquid resin from the runner 7b via the second gate 15. After filling,
By cooling, the resin E being solidified in the upper half (in the first cavity space 13a) of the cavity 13 and the resin in the lower side (in the second cavity space 13b) are united to produce an insert molded product. You.

As described above, the insert molded product is completed through two resin injection steps in the same mold.
And the boundary surface with the resin injected later is integrated. This is because during the resin injection from the second gate 15,
This is because the resin E already filled in the first cavity space 13a is not completely solidified, and therefore, is in close contact with each other in a molten state at the boundary.

The method of opening and closing the first and second opening / closing nozzles 10 and 11 is not limited to the above example, other than the method of sealing by heat as in the above example, and the method of mechanically opening and closing using a valve.

The arrangement of the opening / closing nozzles and the gates communicating therewith is not limited to the above example. For example, regarding the gates, as shown in FIG. 4, if the positions of the first gate 14 and the second gate 15 are arranged so that the method of flowing the resin from each gate is orthogonal,
When the resin is a liquid crystal resin, the resin injected into the first cavity space and the resin injected into the second cavity space are cross-aligned, which has the effect of improving the strength of the molded product.

The types of the first and second gates are also appropriate.
An appropriate system such as a submarine gate and a pinpoint gate can be used in combination.

(Effect of the Invention) As described above, according to the present invention, the insert previously inserted in the cavity does not bend due to the resin pressure injected into the cavity, and the molded product is kept in the same mold. Since molding is possible, it is possible to suppress an increase in equipment cost as compared with the conventional example, and to perform molding efficiently.

[Brief description of the drawings]

1 to 3 are cross-sectional views of a mold showing a molding process step by step, FIG. 4 is an explanatory view showing a gate arrangement position, FIG. 5 (a) is a cross-sectional view of an insert molded product, FIG. FIG. 6B is a cross-sectional view showing one step of a commonly performed insert molding method. FIG. 6 shows a conventional example, and FIG. 6A is a cross-sectional view showing a semi-finished insert molded product. (B) It is sectional drawing which shows one process of the insert molding method using the said semi-finished product. 1 ... fixed-side template, 2 ... movable-side template, 7, 7a, 7b ... runner, 10 ... first opening / closing nozzle, 11 ... second opening / closing nozzle,
12 ... core, 13 ... cavity, 13 a ... first cavity space, 13 b ... second cavity space, 14 ... first gate, 15 ... second gate, d ... moving distance of core, M ... …
insert.

Claims (2)

(57) [Claims] 1. A first opening / closing nozzle (10) for one cavity (13) formed by a fixed mold plate (1), a movable mold plate (2) and a core (12). The first gate (14) communicating with the second opening / closing nozzle (11) and the second gate
In a method for injection molding using a hot runner mold having a second gate (15) communicating with an opening / closing nozzle, first, the fixed mold plate (1) and the movable mold plate (2) After the insert (M) is supported by the core and inserted into a predetermined position in the cavity (13), the movable mold plate is joined to the fixed mold plate. 12) is moved in one direction by a distance (d) to form a first cavity space (13a) on one side of the insert, and the first opening / closing nozzle (10) communicates with the first gate (13). 14) is opened, and the core (12) is in communication with the second opening / closing nozzle (11) and the second gate (15).
Closing the first gate (1) by opening the first opening / closing nozzle (10).
4) a step of injecting a liquid resin into a first cavity space (13a) formed on one side of the insert, and then moving the core (12) in the other direction by a distance (d), A step of opening the second gate (15) and forming a second cavity space (13b) on the other side of the insert in the cavity; and opening the second opening / closing nozzle (11) to open the second gate (15). 2 gates (1
5) a step of injecting a liquid resin into the second cavity space (13b) and cooling and solidifying the liquid resin. 2. A hot runner mold and an insert (M) inserted into a cavity (13) of the mold. The hot runner mold includes a fixed mold plate (1) and a movable mold. One cavity (13) formed by the plate (2) and the core (12), a first opening / closing nozzle (10) for this cavity, and a first gate (14) communicating with the opening / closing nozzle.
And a second opening / closing nozzle (1
1) and the second gate (15) communicating with the second opening / closing nozzle
Wherein the core can reciprocate a predetermined distance (d) in the cavity, and can support the insert (M) at a predetermined position, and when the core moves in one direction, A first cavity space is formed in one side of the insert in the cavity, and the core is configured so that the second gate is closed while the first gate is open, and the core moves in the other direction. A second cavity space is formed in the cavity on the other side of the insert, and the second gate is opened while the first gate is closed. A mold for injection molding of a molded article comprising: