JPH11198195A - Gate cutting method for injection molding die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the exchanging time of gate inserts, prevent a molding quality from lowering and executed a smooth die opening when a gate at an arbitrary part is shut off for molding only specified products at a multi-cavity injection molding die. SOLUTION: In a multi-cavity injection molding die, in which gates G are partitioned by means of the gate recessed parts of respective gate inserts 3 respectively mounted on a fixed die 1 and on a movable die 2 and a plurality of the above-mentioned gates G and of molding cavities are partitioned, in order to shut off arbitrary gates G, the gate inserts 3 on the movable die 2 are exchanged for gate cutting inserts 4 in order to cut off gates G at cutting-off parts. In this case, since the movable die 2 is not a die, with which the exterior surface of a product is molded, no trouble such as the damage of the exterior surface of the product during the exchanging work of inserts develops and a molded body adheringly follows, to the movable die 2, resulting in allowing to realize a smooth die opening.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for shutting off an arbitrary gate of a multi-cavity injection mold having a plurality of gates and a plurality of molding cavities.

[0002]

2. Description of the Related Art Conventionally, in a multi-cavity injection molding die,
When the fixed mold and the movable mold are clamped, a plurality of molding cavities and a gate connected to the molding cavity are defined, and the gate includes a gate insert provided in the fixed mold and a gate provided in the movable mold. May be defined by nesting.

In such an injection molding die, when the molding material is injected only to a specific portion of the molding cavity without injecting the molding material into all the molding cavities for some reason, the remaining gate is shut off. It is necessary to prevent the molding material from being injected into the molding cavity. Conventionally, as shown in FIG. 6, the gate insert of the fixed mold 51 and the gate insert of the movable mold 52 are both cut with a gate. Children 53, 5
3 and the gate 54 is cut off by combining semi-circular cut-off portions that divide the cross-sectional area of the gate G into two.

[0004]

However, the method of replacing both gate inserts as in the prior art requires time for replacement, and works for both the fixed mold 51 and the movable mold 52. For this reason, there is a possibility that an object may be hit against a mold surface (often a fixed mold) for molding the external appearance of the product, thereby causing damage to the molding quality. Further, at the time of release from the mold, the molded product adheres to and follows the mold on one side (often a movable mold) and is subsequently removed.
Has a cut-off portion that divides the gate 54 into two parts, so that it tends to adhere to both the dies 51 and 52 when the dies are opened, resulting in poor releasability.

Therefore, the present invention shortens the replacement time of the gate cut insert, reduces the possibility of damaging the mold surface for molding the external appearance of the product at the time of operation, and improves the releasability when the mold is opened. The purpose is to do.

[0006]

According to the present invention, in order to achieve the above object, a plurality of molding cavities defined by a fixed mold and a movable mold and gate inserts of the fixed mold and the movable mold are provided. In a multi-cavity injection molding die in which a plurality of gates defined by are communicated with each other, in a gate cutting method in which an arbitrary gate is shut off, either a fixed type or a movable type gate insert is inserted. The gate is cut off by replacing it with a gate cut insert having a cut-off portion having substantially the same shape as the cross-sectional shape of the gate.

In this way, only the gate insert on either one of the fixed type or the movable type is replaced with the gate cut insert,
If the gate is cut off at the cut-off portion of the gate cut insert, the gate can be shut off while the gate insert on the other side remains as it is, and the replacement work time is reduced.

In the present invention, the mold for exchanging the gate insert with the gate cut insert is a mold opposite to the mold on the side for molding the external appearance of the product. By doing so, the possibility of damaging the mold surface for molding the external appearance of the product during the operation is reduced, and the molding quality is not reduced.

According to a third aspect of the present invention, the mold for exchanging the gate insert with the gate cut insert is a mold on the side to which a molded product adheres at the time of mold release. That is, the molding material has reached the gate cut insert, and the tip end of the molding material is in contact with the blocking portion of the gate cut insert. For this reason, if the gate cut insert is the mold to which the molded product adheres at the time of mold release, the mold can be opened smoothly.

[0010]

Embodiments of the present invention will be described with reference to the accompanying drawings. Here, FIG. 1 is an explanatory view showing a mold surface of a fixed mold, FIG. 2 is a longitudinal sectional view showing a state in which a molding cavity is defined by a fixed mold and a movable mold, and FIG. 3 is a gate insert provided in the fixed mold and the movable mold. FIG. 4 is a partial sectional view showing a state in which a movable gate insert is replaced with a gate cut insert, and FIG. 5 is a combination state of a gate insert and a gate cut insert. It is a perspective view explaining.

The gate cutting method for an injection molding die according to the present invention uses an injection molding die for simultaneously molding the left and right bumper corners of an automobile by using only one molding cavity for some reasons. It has been proposed as an improved technique for blocking the injection of molding material into the molding cavity on the other side when molding only one bumper corner, shortening the working time to convert to a structure for blocking, Care has been taken to eliminate defects that would degrade the quality and to enable smooth mold opening.

That is, when the fixed mold 1 and the movable mold 2 as shown in FIG. 2 are clamped, a pair of left and right molding cavities C for molding left and right bumper corners are provided.
, And a gate G (FIG. 3) communicating with each molding cavity C is formed. Therefore, a pair of left and right cavity concave portions Ca as shown in FIG.
The gate insert 3 is attached in the middle of the passage concave portion connecting the cavity concave portion Ca and the injection portion T. On the front surface of the gate insert 3, a gate recess Ga as shown in FIG.

A cavity recess Ca (not shown) is also formed on the mold surface of the movable mold 2 in correspondence with the fixed mold 1 and a gate insert 3 is attached. A concave portion Ga is formed. When the fixed mold 1 and the movable mold 2 are clamped, a molding cavity C is defined by the cavity concave parts Ca, Ca, and the gate concave parts Ga,
The gate G is defined by Ga.

The molding material injected from the injection part T is filled into the left and right molding cavities C through the gates G of the respective gate inserts 3 to form a pair of bumper corners. The fixed mold 1 side is the outer appearance surface side of a product requiring appearance quality. Also, after the molding, when the mold is opened, the molded article adheres to and follows the movable mold 2, and is thereafter extruded and removed from the movable mold 2.

In the above-described injection mold, when molding only one of the left and right bumper corners from the relation of parts and the like, the gate G on the other side is shut off and the molding material is injected. In this case, in the present invention, a gate cut insert 4 as shown in FIGS. 4 and 5 is used, and this is combined with the gate insert 3 to shut off the gate G.

That is, only the gate insert 3 on one side is replaced with the gate cut insert 4 and the gate G is cut off while the other gate insert 3 remains as it is. A circular cut-off portion 4s (FIG. 5) having the same shape as that of the gate G is provided, and the cut-off portion 4s is added to the gate insert 3.

For this reason, as compared with the conventional case in which both the gate inserts 3 of the fixed type 1 and the movable type 2 are replaced with the gate cut inserts 53 (FIG. 6) in order to cut off the gate G, only one side is replaced. Since the replacement is sufficient, the working time can be reduced.

The mold to be replaced with the gate cut insert 4 is a movable mold 2. By replacing the gate insert 3 of the movable mold 2 with the gate cut insert 4 in this way, it is possible to prevent a problem that the operator damages the mold surface (fixed mold 1) on the external appearance surface side when performing the replacement work. Even if the tip of the molding material reaching the blocking portion 4s adheres to the blocking portion 4s, the molded product adheres to the movable mold when the mold is opened, so that it does not hinder the mold opening. The mold can be opened smoothly.

The present invention is not limited to the above embodiment. Those having substantially the same configuration as those described in the claims of the present invention and exhibiting the same operation and effect belong to the technical scope of the present invention. For example, a molded article is an example, and the number of multi-cavities is arbitrary.

[0020]

As described above, the gate cutting method for an injection molding die according to the present invention is a gate cutting method for cutting off an arbitrary gate in a multi-cavity injection molding die. In the method, the gate is cut off by replacing either the fixed type or the movable type gate insert with a gate cut insert having a cut-off portion having substantially the same sectional shape as the gate, so that the other side is used. The gate nest can be shut off as it is, and the replacement time can be shortened. In addition, if the mold to be replaced with the gate cut insert is a mold opposite to the mold for molding the external appearance of the product, there is a possibility that the mold surface corresponding to the external appearance of the product will be damaged during work. And no deterioration in molding quality. Further, if the mold to be replaced with the gate cut insert is the mold to which the molded product adheres at the time of release,
The mold can be opened smoothly.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a fixed mold surface.

FIG. 2 is a longitudinal sectional view showing a state in which a molding cavity is defined by a fixed mold and a movable mold.

FIG. 3 is a partial cross-sectional view of a state where a gate is defined by gate inserts provided for a fixed type and a movable type.

FIG. 4 is a partial cross-sectional view showing a state where a gate cut insert according to the present invention is replaced with a movable gate insert.

FIG. 5 is a perspective view illustrating a combined state of a gate cut insert and a gate insert according to the present invention.

FIG. 6 is an explanatory view of a conventional gate cut insert.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... fixed type, 2 ... movable type, 3 ... gate insert, 4 ... gate cut insert, 4s ... interruption part, C ... molding cavity, G ...
Gate.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Seiji Sasaki 1907 Hirata-cho, Suzuka City, Mie Prefecture Inside Honda Motor Co., Ltd. Inside Suzuka Factory

Claims (3)

[Claims] 1. A multi-cavity injection mold in which a plurality of molding cavities defined by a fixed mold and a movable mold and a plurality of gates defined by gate inserts of the fixed mold and the movable mold are communicated. What is claimed is: 1. A gate cutting method in which an arbitrary gate is cut off by a mold, wherein the gate insert of either the fixed type or the movable type has a cut-off portion having substantially the same cross-sectional shape as the gate. A gate cutting method for an injection molding die, wherein a gate is shut off by exchanging a nest. 2. The method for cutting a gate of an injection molding die according to claim 1, wherein the mold for exchanging the gate insert for the gate cut insert is a mold opposite to a mold for molding a product external surface. A gate cutting method for an injection mold. 3. The method of cutting a gate of an injection mold according to claim 1, wherein the mold for replacing the gate insert with the gate cut insert is a mold to which a molded product adheres at the time of mold release. A gate cutting method for an injection molding die.