JPH0195020A - Mold provided with gate cut-off mechanism - Google Patents

Abstract

PURPOSE:To enable a product to be automatically cut off from a runner member in a mold wherein a cavity is connected to a runner through a side gate, by providing a movable retainer plate with a gate cut-off mechanism adopted to cut off a gate member after opening a mold and protruding an ejector pin. CONSTITUTION:When molten resin is injected into a clamped mold, the resin is filled in a cavity 11 through a runner 12 and a side gate 13. When the filled resin is cooled and a movable retainer plate 2 is moved backward, a molding 3 is released from a cavity retainer plate 1, moved backward together with the movable plate 2, and pushed out of the plate 2 by means of an ejector pin 4. Since, however, a gate cut-off mechanism 5 attached to the movable plate 2 crosses a gate member 33, a product 31 is cut off from the member 33 by protruding the pin 4 after opening the mold.

Description

[Detailed Description of the Invention] [Summary] Regarding the configuration of a molding die equipped with a side gate, the purpose of this invention is to automatically separate a molded product from a runner member, and to connect a cavity and a runner with a side gate. In this mold, a gate cutting mechanism 5 for cutting the gate member 33 after opening the mold is provided on the movable mold plate 2, and the product 31 and the runner member 3 are cut by protruding the ejector pin 4.
2 are configured so that they are automatically separated.

[Industrial application field]

The present invention relates to the configuration of a mold for molding plastic products,
In particular, the present invention relates to a molding die equipped with a mechanism for automatically separating a product from a runner member.

Generally, a molding mold has a cavity and a runner connected by a side gate, and when such a mold is filled with molten resin and the resin is cured, the product is released in the cavity, the runner member is in the runner, and Gate members are formed in each side gate. Therefore, the molded product taken out from the mold has the product, the runner member, and the gate member integrated, and the product is separated from the runner member as a post-process.

However, post-processing not only involves separating the product from the runner member, but also includes shaping and finishing of the cut end, and in mass-produced products, post-processing costs account for a large amount of manufacturing cost. Therefore, there is a need to develop a molding die equipped with a gate cutting mechanism that automatically separates the product from the runner member during the molding process.

[Conventional technology]

FIG. 3 is a side sectional view showing the structure of a conventional molding die.

In Fig. 3(a), the normal molding die is fixed side template 1.
and a movable template 2. For example, the stationary template 1 has a cavity 11, a runner 12, and a side gate 13 formed therein. When the movable mold plate 2 is moved back after being filled with molten resin and cooled, the molded product 3 separates from the fixed mold plate 1 and retreats together with the movable mold plate 2. Furthermore, by the action of the ejector pin 4, the molded product 3 moves away from the movable mold plate 2. It is pushed out from plate 2. However, as shown in the figure, in the molded product 3 formed using a mold having a side gate, the product 31 and the runner member 32 are connected by the gate member 33, and post-processing is required to separate the product 31 from the runner member 32. shall be.

Therefore, as a molding mold equipped with a mechanism for automatically separating the product 31 from the runner member 32, a mold equipped with a submarine gate as shown in FIG. 3(b) is sometimes used. That is, a cavity 11, a runner 12, and a submarine gate 14 are formed in the stationary template 1, and the submarine gate 14 is hidden inside the stationary template 1. When the movable mold plate 2 is moved back after being filled with molten resin and cooled, the molded product 3 is retracted together with the movable mold plate 2, but at this time, the gap between the product 31 and the gate member 34 is cut, resulting in a separated product. 31 and runner member 32 are each pushed out by the ejector pin 4.

[Problem that the invention seeks to solve]

When molding is performed using a molding die having a submarine gate, the product and the runner member can be automatically separated as described above. However, in submarine gates, defects such as inability to fill due to pressure loss and so-called jetting, in which lines appear in the flow direction of the resin, may occur. Therefore, when molding products that are prone to warping defects, it is necessary to connect the cavity and the runner with a side gate, and there is a problem in that the product and the runner member cannot be automatically separated.

[Means for solving problems]

FIG. 1 is a side sectional view showing an embodiment of a molding die according to the present invention. The same objects are represented by the same symbols throughout the plan.

The above problem occurs when the mold is formed by connecting the cavity and runner with a side gate, and after opening the mold, the gate member 3
A gate cutting mechanism 5 for cutting 3 is provided on the movable template 2,
This problem is solved by the molding die with a gate cutting mechanism of the present invention, which is configured such that the product 31 and the runner member 32 are automatically separated by protruding the ejector pin 4.

[Effect]

In FIG. 1, the gate cutting mechanism 5 provided on the moving template 2
straddles the gate member 33, and by protruding the ejector pin 4 after opening the mold, the product 31 and the gate member 33 are separated.
The gap between them is cut off. That is, in a molding process using a molding die equipped with a side gate, the product and the runner member can be automatically separated by providing a gate cutting mechanism on the movable mold plate and protruding an ejector pin.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that FIG. 2 is a side sectional view showing another embodiment of the present invention.

In FIG. 1, the molding die according to the present invention is a fixed side mold plate 1.
and a movable mold plate 2. For example, the fixed mold plate 1 has a cavity 11 and a runner 12 formed therein. On the other hand, a gate cutting mechanism 5 is fixed to the movable mold plate 2, and the gate cutting mechanism 5 is fitted into the fixed mold plate l, and its side surface forms a part of the cavity 11. Further, a side gate 13 connecting the cavity 11 and the runner 12 passes through the gate cutting mechanism 5.

When the molding die is clamped and molten resin is injected, the resin is filled into the cavity 11 via the runner 12 and the side gate 13. When the movable mold plate 2 is moved back after the resin filled in the mold is cooled, the molded product 3 separates from the fixed mold plate 1 and retreats together with the movable mold plate 2, and is further moved by the action of the ejector bin 4. It is extruded from the side template 2.

However, the gate cutting mechanism 5 fixed to the movable mold plate 2 straddles the gate member 33, and after opening the mold, the ejector pin 4
By protruding, the gap between the product 31 and the gate member 33 is cut.

In addition, in FIG. 2, the molding die consists of a fixed side mold plate 1 and a movable side mold plate 2. For example, the fixed side mold plate 1 has a cavity 1.
1, a runner 12, and a side gate 13 are formed. On the other hand, a gate cutting mechanism 5 is mounted on the movable template 2 so as to be slidable in a direction perpendicular to the plane of the paper. The gate cutting mechanism 5 has a cutter 51 at its tip for cutting the gate member 33, and when the gate cutting mechanism 5 is slid after opening the mold, the cutter 51 moves above the gate member 33. After that, when the ejector bin 4 is pushed out, the product 31 and the gate member 33
The gap between them is cut off.

In a molding process using a molding die equipped with a side gate, the product and the runner member can be automatically separated by providing a gate cutting mechanism on the movable mold plate and protruding the ejector bin.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a molding die equipped with a gate cutting mechanism that automatically separates the product from the runner member.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view showing one embodiment of a molding die according to the present invention, Fig. 2 is a side sectional view showing another embodiment of the present invention, and Fig. 3 is a side sectional view showing a conventional forming die. This is a side sectional view showing the configuration. In the figure, ■ is the fixed side template, 2 is the movable side template, 3 is the molded product, 4 is the ejector bin, 5 is the gate cutting mechanism, 11 is the cavity, 12 is the runner, 1
3 represents a side gate, 31 represents a product, 32 represents a runner member, 33 represents a gate member, and 5I represents a cutter.

Claims (1)

[Claims] 1) In a molding die in which a cavity and a runner are connected by a side gate, a gate cutting mechanism (5) that cuts the gate member (33) after opening the mold is connected to the movable side template (2). A molding die with a gate cutting mechanism, characterized in that the product (31) and the runner member (32) are automatically separated by protruding an ejector pin (4). 2) A molding die with a gate cutting mechanism according to claim 1, wherein the gate cutting mechanism (5) is fixed to the movable mold plate (2). 3) A molding die with a gate cutting mechanism according to claim 1, wherein the gate cutting mechanism (5) is slidably mounted on the movable template (2).