JPH02303811A - Injection molding method and mold therefor - Google Patents

Abstract

PURPOSE:To mold resin in the same mold and to inhibit the cost of equipment from being raised by providing at least two opening/closing nozzles for one cavity and equipping the gates correspondent to the respective opening/closing nozzles respectively. CONSTITUTION:A cavity 13 is formed by both a stationary retainer plate 1 and a movable retainer plate 2 and a core 12 in the interval of the opposite faces of both the retainer plates 1, 2. A first opening/closing nozzle 10 is opened and a second opening/closing nozzle 11 is closed. Therein when liquid resin is packed into a sprue bush 5 through an injection nozzle, liquid resin is introduced into a first cavity space 13a of the cavity 13 via a first gate 14 from the runners 7a, 7b. When the second opening/closing nozzle 11 is opened and introduction of resin is started, liquid resin is packed to a second cavity space 13b via a second gate 15 from the runner 7b.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an injection molding method and a mold capable of molding a molded article having a bendable insert into a part by the pressure of a resin injected into a cavity.

(Conventional technology).

Generally, when molding a molded product P having a thin and long insert M, as shown in FIG. 5(a), for example, the fixed side mold plate Ka and the movable side of the mold are If the insert M is placed in the cavity C formed by the template Kb and then filled with resin from the gate G, the insert is long and thin, so there is an inconvenience that the insert is bent as shown by the chain line by the pressure of the resin.

Therefore, conventionally, one injection molding method is shown in Fig. 6 (a).
), first, a semi-molded product Pa with an insert M fixed thereon is molded using a mold for primary molding, the insert is fixed, and then this semi-molded product Pa is molded as shown in the same figure (b).
As shown in FIG. 2, the resin was placed in the cavity C1 of another secondary molding die and then filled with resin from the gate G1.

K1 is a stationary template, and K2 is a movable template.

(Problems to be Solved by the Invention) In the conventional method, molding is divided into primary and secondary molding, and separate molds are used for each molding, which takes time and effort. Furthermore, there is a problem in that equipment costs are increased due to the use of separate molds.

An object of the present invention is to prevent equipment costs from increasing and to enable efficient molding.

(Means for Solving the Problems) The injection molding method of the present invention uses a hot runner having at least two opening/closing nozzles 10.11 for one cavity 13 and gates 14, 15 corresponding to each opening/closing nozzle. - Using a mold, first open and close one of the first opening/closing nozzles 1.
0 is opened, the core 12 constituting the cavity closes the second gate 15 corresponding to the second opening/closing nozzle 11, and the first gate communicating with the first opening/closing nozzle enters the first cavity space 13a. After injecting the resin and subsequently moving the core to open the second gate and providing the second cavity space 13b in the cavity, the second
An opening/closing nozzle is opened, and resin is injected into the second cavity space through a second gate communicating with the opening/closing nozzle, and is cooled and solidified.

The mold of the present invention is a hot runner mold in which one cavity 13 is provided with at least two opening/closing nozzles 10.11 and gates 14.15 corresponding to each opening/closing nozzle. The cavity 13 is composed of a fixed mold plate 1, a movable mold plate 2, and a core 12, the core is movable by a predetermined distance 1111d, and either one of the gates is located within the movement range of the core. (Example) Examples of the present invention will be described below with reference to the drawings.

First, the injection molding mold will be explained, and then the injection molding method will be explained.

Parting lie on the opposing surfaces as shown in Figure 1.

Of the fixed side template 1 and movable side template 2 forming the fixed side template 1, the fixed side template 1 located on the upper side is attached to the fixed side mounting plate 3.
is attached to. A hot runner block 4 is provided inside each of the stationary side mold plate 1 and the stationary side mounting plate 3, extending over both. A sprue bush 5 is formed at the center of the upper part of the hot runner block, and an injection nozzle is located above the sprue bush so as to face the sprue bush. The sprue 6 in the sprue bush 5 runs from the runner 7 provided in the hot runner block 4 to the first gate portion 8.9 of the gate portion 8.9 provided on both sides of the lower part of the hot runner block. Runner 7m leading to the second opening/closing nozzle 10.11 and further reaching the parting line.

It communicates with 7b. A cold valve is used for each opening/closing nozzle io and ii to enable opening and closing of the nozzle.

A cavity 13 is formed between the opposing surfaces of the stationary mold plate 1 and the movable mold plate 2, and the mold plates and the core 12 form a cavity 13. As shown in FIG. 1.2, the cavity 13 is connected with a first gate 14 communicating with the runner 7a on the left side, and with a second gate 15 communicating with the runner 7b on the right side. The upper surface of the core 2 constitutes the bottom surface of the cavity 13,
It has a function of supporting the insert M inside the cavity. The core 12 has a pin 1 protruding from the plate 16.
7, and the plate is movable by actuation of a cylinder 18.

The plate 16 moves against the spring 22 in a space surrounded by a back plate 19 arranged on the back side of the movable template 2 and a spacer block 21 between this back plate and the movable mounting plate 2. It is arranged so that it can be moved.

Therefore, by operating the cylinder 18, the pin 17 moves up and down, so the core 12 moves by a maximum travel distance of 6 minutes, and this movement increases or decreases the volume of the cavity 13, and in the example of FIG. By moving, the first cavity space 13a having the minimum volume is formed.

The core 12 is connected to the second cavity 13 which is open into the cavity 13.
It has a function of opening and closing the gate 15, and in the state shown in the first diagram, the second gate is closed.

Next, an injection molding method for insert molded products will be explained with reference to FIGS. 1 to 3.

The cylinder 18 is actuated in advance to move the core 12 constituting the cavity and tee 13 upward by a distance d to the position shown in FIG.
Only 3a) is left and the volume of the cavity is made small. At this time, the second gate 15 is closed on the side surface of the core 12. Then, the first opening/closing nozzle 10 is opened and the second opening/closing nozzle 11 is closed.

Therefore, the liquid resin was spouted from the injection nozzle to the sprue bush 5.
As the liquid resin is filled from the lunch 7°7a to the first
It is injected into the first cavity space 13a of the cavity 13 through the gate 14. At this time, the resin is 12 gates 1
5 is closed, so that the flow does not flow back to the runner 7b side.

When the core 12 is moved downward a distance of 6 minutes as shown in FIG. 2 after a predetermined period of time has elapsed after completion of the injection, a second cavity space 13b is formed in the lower half of the cavity 13. At this time, the second gate 15 is opened. after that,
As shown in FIG. 3, when the second opening/closing nozzle 11 is opened to start injection of resin, liquid resin is filled from the runner 7b through the second gate 1 into the second cavity space 13b.

After filling, by cooling, the resin E that is being solidified in the upper half of the cavity 13 and the lower resin are combined to produce an insert molded product.

In this way, the insert molded product is completed through two resin injection steps in the same mold, but the interface between the resin E that was injected first and the resin that was injected later are integrated.

This is because during the resin injection from the second gate 15, the resin E that has already filled the first cavity space 13a is not completely solidified, so the resin E is adhered to each other in a molten state at the boundary. be.

The opening/closing method of the opening/closing nozzle 10.11 is not limited to the above example, and includes a method of mechanically opening/closing using a valve, in addition to a heat sealing method as in the above example.

The number and arrangement of opening/closing nozzles and gates communicating therewith are not limited to the above example. For example, regarding gates, if the positions of the first gate 14 and the second gate 15 are arranged so that the directions of resin flowing out from each gate are perpendicular to each other as shown in FIG. The resin injected into the first cavity space and the resin injected into the second cavity space are cross-oriented, which has the effect of improving the strength of the molded product.

1st. The type of the second gate is also appropriate, such as a side gate,
Appropriate systems such as submarine gates and bin point gates can be combined and constructed.

(Effects of the Invention) As described above, according to the present invention, since molding can be performed within the same mold, equipment costs can be suppressed from increasing compared to the conventional example, and molding can be performed efficiently.

[Brief explanation of the drawing]

Figures 1 to 3 are cross-sectional views of the mold showing the molding process step by step, Figure 4 is an explanatory diagram showing the placement position of the gate, and Figure 5 (a)
5215 is a cross-sectional view of an insert molded product, and FIG. 5215 (b) is a cross-sectional view showing one step of a commonly used insert molding method. FIG. 6 shows a conventional example; FIG. 6 (a) is a sectional view showing a semi-finished insert molded product, and FIG. 6 (b) is a sectional view showing one step of the insert molding method using the above 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, 13b...second cavity space, 14...first gate, 15...second gate, d...
- Distance traveled by the core. Above Figure 1 Figure 2 Figure 4 Cause Figure 5 (α) Figure 6

Claims (1)

[Claims] 1. Using a hot runner mold having at least two opening/closing nozzles for one cavity and a gate corresponding to each opening/closing nozzle, one first opening/closing nozzle is first opened. , the core constituting the cavity closes the second gate corresponding to the second opening/closing nozzle, injecting resin into the first cavity space from the first gate communicating with the first opening/closing nozzle, and then The core is moved to open the second gate and the second gate is placed in the cavity.
An injection molding method characterized in that after a cavity space is provided, a second opening/closing nozzle is opened and resin is injected into the second cavity space through a second gate communicating with the opening/closing nozzle, and is cooled and solidified. 2. A hot runner mold having at least two opening/closing nozzles for one cavity and a gate corresponding to each opening/closing nozzle, the cavity having a fixed side template, a movable side template, and a core. The mold is characterized in that the core is movable a predetermined distance, and either one of the gates is located within a movement range of the core and is opened and closed by the core.