JPH09225975A - Injection molding die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cut and seal a gate simultaneously and manufacture a molded product of superior outer appearance by cutting the gate while the gate is sealed by a gate cut pin provided on the movable side of an injection molding die after injection filling. SOLUTION: First, a movable side template 2 of an injection molding die 1 is moved forward, and the movable side template 2 is made to conform with a fixed side template 3 and the mold is closed, and molten resin is injected from a resin injection hole 32 provided on the fixed side template 3. The injected resin is filled in a cavity, and then a hydraulic cylinder 6 is acuated, and a gate cut pin 5 is moved forward, and resin at the end of the gate cut pin 5 is pushed in, and a gate G is cut while being sealed. The cutting and sealing of the gate G, therefore, can be carried out simultaneously to solve a problem of adhesion of cutting waste to the mold and eliminate the necessity of finishing a cut face. Also the defects like a short shot and others are not generated, and a molded product P of superior outer appearance can be manufactured.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an injection mold capable of simultaneously sealing and cutting a gate.

[0002]

2. Description of the Related Art In a conventional injection molding die, a gate having a remarkably narrowed flow path is provided between a product portion which is a product of a molded article and a runner portion which is cut and discarded. The gate was preferentially solidified to stop pressure transmission and seal the gate. Also, the actual Kaihei 1-7
In the injection molding die described in Japanese Patent No. 2315, the gate is cut by changing the timing of the protrusion of the product and the runner with the pin that starts the mold opening after the cooling is finished and the spacer for adjusting the delay amount. And the product was sticking out at the same time.

[0003]

However, in the above-mentioned conventional injection mold, the gate is narrowed, which causes the appearance of the molded product, such as a short shot, a burn, and a silver flash. . In addition, when the product and the runner are separated, since they are completely solidified and then separated, there is a problem that the cut waste adheres to the mold and appears on the next molded product, which adversely affects the appearance quality. . Furthermore, there is a problem that the gate surface must be finished after the molded product is taken out.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and an object of the present invention is to enable cutting and sealing of a gate at the same time and to obtain a molded product having an excellent appearance. An object is to provide an injection mold.

[0005]

The present invention has been made to achieve the above object, and an injection molding die according to claim 1 is a gate cut for cutting a gate of a molded article. The pin is provided on the movable side of the injection molding die, and the gate cut pin is provided with means for cutting the gate while sealing the gate after injection filling.

In the injection molding die according to claim 2, a gate cut pin for cutting the gate of the molded product and an ejector plate are provided on the movable side of the injection molding die.
The gate cut pin can be cut while sealing the gate after injection filling with a hydraulic cylinder attached to the ejector plate, and when the mold is opened, the ejector pin attached to the ejector plate and the gate cut pin project the molded product It is done like this.

(Operation) In the injection molding die of claim 1, a gate cut pin for cutting the gate of the molded product is provided on the movable side of the injection molding die, and the gate cut pin is the gate after injection filling. Since a means for cutting the gate while sealing is provided, the gate can be cut and sealed at the same time, the problem that cutting waste adheres to the mold is solved, and the finishing of the cut surface is unnecessary. Further, since the gate cut pin is provided, it is not necessary to narrow the flow path of the gate, so that defects such as short shots, burns, and silver flash do not occur, and a molded product having an excellent appearance can be obtained.

In the injection molding die according to the second aspect of the present invention, the gate cut pin can be cut while sealing the gate after injection and filling by the hydraulic cylinder attached to the ejector plate. Cutting and sealing can be performed at the same time, the problem that cutting waste adheres to the mold is solved, and the finishing of the cutting surface is also unnecessary.
Further, since the gate cut pin is provided, it is not necessary to narrow the flow path of the gate, so that defects such as short shots, burns, and silver flash do not occur, and a molded product having an excellent appearance can be obtained. Further, when the mold is opened, the ejector plate attached to the ejector plate and the gate cut pin project the molded article, so that the molded article can be easily taken out.

[0009]

FIG. 1 shows a first embodiment of the present invention.
3 and FIG. 4 shows another embodiment of the present invention.
1 is a side sectional view of an injection molding die immediately after injection, FIG.
(A) and (B) are explanatory views showing an operating state of the gate seal pin, and FIG. 3 is a cross-sectional view of a main part of the injection mold of FIG. 1 in a mold open state. FIGS. 4A and 4B are explanatory diagrams showing the operating states of the gate and the gate seal pin, which have different shapes.

1 to 4, 1 is an injection molding die,
2 is a movable side mold plate, 3 is a fixed side mold plate, 4 is an ejector plate, 41 is an ejector pin, 5 is a gate seal pin, 6 is a hydraulic cylinder, and P and P1 are molded products.

First, a first embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. The injection molding die 1 includes a movable side mold plate 2 and a fixed side mold plate 3 that slide forward and backward, and a movable side mounting plate 21 is attached to the movable side mold plate 2 via a spacer 22. An ejector plate 4 is provided in the spacer 22, and a plurality of ejector pins 41 and 42 are provided on the ejector plate 4 in a protruding manner.
The ejector plates 41 and 42 can be moved back and forth by penetrating the movable side mold plate 2 and sliding the ejector plate 4 by a sliding mechanism (not shown).

Further, the movable mold plate 2 is provided with a gate seal pin 5 operated by a hydraulic cylinder 6. As shown in FIG. 2 (a), the gate seal pin 5 is located at the position where the gate G is opened until immediately before the resin is injected. However, as shown in FIG. 2 (b), the resin is injected. Immediately after the operation, the hydraulic cylinder 6 protrudes in the direction of the stationary mold plate 3 to cut the gate G while sealing it. P is a molded product that has been molded.

The fixed-side mold plate 3 has a cavity formed in a mold surface corresponding to the movable-side mold plate 2, and a fixed side provided with a molten resin injection port 32 on the side opposite to the mold surface. A mounting plate 31 and a runner payout plate 31 are provided. A nozzle of an injection molding machine (not shown) is brought into contact with the injection port 32, and the molten resin supplied from the injection molding machine passes through the runner R and the gate G and is filled in the cavity of the injection molding die 1. It

Next, the operation of the present embodiment will be described while explaining the molding process of the molded product P using the injection molding die 1 shown in the present embodiment. First, the movable side mold plate 2 of the injection molding die 1 is moved forward, the movable side mold plate 2 and the fixed side mold plate 3 are aligned to close the mold, and the resin injection port 32 provided in the fixed side mold plate 3 is closed. The molten resin is injected and injected from. After the injected resin is filled in the cavity, the hydraulic cylinder 6 is operated to move the gate seal pin 5 forward, the resin at the tip of the gate seal pin 5 is pushed in, and the gate G is cut while sealing. The timing of the gate sealing may be immediately after injection filling, but if the timing is shifted and sealing is performed, a holding pressure for injection can be applied to the resin in the cavity, so that the appearance such as a sink mark of the molded product P is improved. Then, after cooling the injected molten resin, the movable side mold plate 2 is retracted to open the mold, and the ejector plate 4 is moved toward the fixed side mold plate 3 as shown in FIG. Molded product P is ejector pin 41, 41
With the wall thickness control pin 5, the gate G is projected by the ejector pin 42, and the molded product P separated from the gate G can be taken out.

In the injection molding die 1 described above, a gate cut pin 5 for cutting the gate G of the molded product P molded.
Is provided on the movable side mold plate 2 of the injection molding die 1, and the gate cut pin 5 cuts while sealing the gate G after injection filling. The problem of sticking to the mold 1 is solved, and the finishing of the cut surface is also unnecessary. Also, gate cut pin 5
Since it is not necessary to narrow the flow path of the gate G, defects such as short shots, burns and silver flash do not occur, and a molded product P having an excellent appearance can be obtained.

When the mold 1 is opened, the molded product P is ejected by the ejector pin 41 attached to the ejector plate 4 and the wall thickness control pin 5, so that the molded product P is formed.
Can be easily taken out.

Next, another embodiment of the present invention will be described with reference to FIG. In FIG. 4, the same parts as those in the above-described embodiment are indicated by the same reference numerals, and different parts are indicated by different reference numerals.
Descriptions of the same reference numerals are omitted.

In the present embodiment, the gate G1 is a tunnel gate. The gate cut pin 5 opens the gate G1 before injection, but moves forward after injection filling and cuts while sealing the gate G1.

The method of use and the operation of the injection mold provided with the gate G1 are the same as those of the injection mold 1 described above, and the description thereof will be omitted to avoid duplication.

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific structure is not limited to this embodiment, and there are design changes within the scope not departing from the gist of the present invention. Also included in the present invention. For example, in the first embodiment, the hydraulic cylinder 6 that operates the gate cut pin 5 is attached to the ejector plate 4, but it may be attached to the movable side mold plate 2.

[0021]

According to the first and second aspects of the present invention, since the gate cut pin cuts the gate while sealing the gate after injection filling, the gate can be cut and sealed at the same time. The problem of sticking to the mold is solved, and there is no step on the cut surface, so no finishing is required.
Further, since the gate cut pin is provided, it is not necessary to narrow the flow path of the gate, so that defects such as short shots, burns, and silver flash do not occur, and a molded product having an excellent appearance can be obtained. Furthermore, since the gate seal can be formed immediately after injection filling, the molding cycle can be shortened.

In addition to the above effects, in the injection molding die of claim 2, when the mold is opened, a molded product is projected by an ejector pin attached to an ejector plate and the gate cut pin. Therefore, it is easy to take out the molded product.

[Brief description of drawings]

FIG. 1 shows a first embodiment of the present invention and is a side sectional view of an injection molding die immediately after injection.

2A and 2B are explanatory views showing an operating state of a gate seal pin.

FIG. 3 is a cross-sectional view of essential parts of the injection molding die in FIG. 1 in a mold open state.

FIG. 4 shows another embodiment of the present invention,
(B) and (B) are explanatory drawings which show the operating state of the gate and gate seal pin which were made into another shape.

[Explanation of symbols] 1 injection molding die 2 movable side mold plate 3 fixed side mold plate 4 ejector plate 41 ejector pin 5 gate seal pin 6 hydraulic cylinder P, P1 molded product

Claims (2)

[Claims] 1. A gate cut pin for cutting a gate of a molded product is provided on a movable side of an injection mold, and the gate cut pin is provided with means for cutting the gate while sealing the gate after injection filling. An injection mold that is characterized by 2. A gate cut pin for cutting a gate of a molded product and an ejector plate are provided on a movable side of an injection molding die, and the gate cut pin is injected and filled by a hydraulic cylinder attached to the ejector plate. The injection molding mold is characterized in that the gate can be cut while sealing the seal, and when the mold is opened, the molded product is ejected by the ejector pin attached to the ejector plate and the gate cut pin.