JPH07186210A - Injection molding die - Google Patents

Abstract

PURPOSE:To ensure the removal of a spool runner by forming a columnar protrusion part having the same axial core as a spool part on a spool runner, as the holding part of a holding means. CONSTITUTION:A runner forming part 52 has a recessed hole 52b formed at a part corresponding to a gate part-forming part 52a and a spool-forming part 51. Consequently, the runner part 82 constituting a spool runner 8 is equipped with a columnar protrusion part 82b formed by a molten resin flowing into a gate part 82a and the processed part 52b. This columnar protrusion part 82b has the same axial core as a spool part 81 protruding into a movable die 3 side. Thus the spool runner 8 can be removed from a runner stripper plate 22 by holding the columnar protrusion part 82b using a holding means 9 and pulling it toward a movable side die plate 31 side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection mold.

[0002]

2. Description of the Related Art An injection molding die having a pin point gate does not leave a scar on the molded product, and the gate is cut and taken out from the die, which saves the trouble of cutting the gate and solidifies the gate. Since it is fast, it has the advantage that there are few internal defects near the gate of the molded product.

As this type of injection molding die, for example, a die having a three-plate structure as disclosed in Japanese Patent Publication No. 4-19009 is generally used. As shown in FIG. 3, a three-plate structure mold generally includes a fixed mold 100 and a movable mold 200, and the fixed mold 100 is composed of a fixed-side mold plate 101 and a runner stripper plate 102.

Then, as shown in FIG.
When separating the movable mold 200 and the movable mold 200 and taking out the molded product 300, the stationary mold plate 101 and the runner stripper plate 1
02 and 02 are split at the same time so that the sprue runner 400 can be removed. That is, the sprue runner 40
As shown in FIG. 4 and FIG. 5, the reference numeral 0 holds the gate portion 402 of the runner portion 401 by the holding means 500 such as a magic hand hanging from directly above the gate portion 402, and the holding means in the direction of the arrow in FIG. Move 500 to remove it from the mold. Next, the removed sprue runner 400 is sent to a conveyance means such as a belt conveyor to be collected and reused as a raw material.

[0005]

However, as shown in FIGS. 4 and 5, since the sprue portion 403 and the gate portion 402 of the runner portion 401 are in the eccentric position, the gate portion 4
With the weight of 02, the sprue runner 400 rotates around the sprue portion 403 in the direction of the arrow, and the gate portion 402 is no longer located directly below the holding means 500, so that the holding means 500 can hold the gate portion 402 well. There is a risk of disappearing.

In view of such circumstances, it is an object of the present invention to provide an injection molding die capable of reliably taking out the sprue runner.

[0007]

In order to achieve such an object, an injection molding die according to the present invention is an injection molding die having a sprue and runner forming portion, which is coaxial with the sprue forming portion. The runner forming portion is provided with a recessed portion that projects toward the opposite side of the sprue portion and forms a columnar protruding portion in the runner portion that serves as a holding portion of the holding means when the sprue runner is taken out.

[0008]

According to the above construction, when the mold is opened, even if the sprue runner rotates about the sprue as a central axis due to the weight of the gate, the columnar protrusion formed by the resin that has entered the recess is coaxial with the sprue. Since it is provided so as to project upward, the position of the columnar projection does not move and is always held at a fixed position with respect to the fixed mold.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings showing the embodiments thereof. FIG. 1 shows one embodiment of an injection molding die according to the present invention when viewed in cross section.
As shown in the drawing, the mold 1 includes a fixed mold 2 and a movable mold 3, and a cavity 4 is formed by closing the fixed mold 2 and the movable mold 3 together.

The stationary mold 2 is composed of a stationary mold plate 21 and a runner stripper plate 22.
The sprue runner forming portion 5 is formed by closing the runner stripper plate 22 and the runner stripper plate 22.
The sprue runner forming portion 5 includes a sprue forming portion 51 and a runner forming portion 52.

The runner forming portion 52 is the gate portion forming portion 5
2a and a portion corresponding to the sprue forming portion 51, a recessed hole 52b
Are formed. The recessed hole 52b has the same axial center as the sprue forming portion 51, and a molten resin enters during the injection molding to form a columnar protruding portion described later.

In the figure, 11 is a protruding pin of a molded product, 23 is a fixed die mounting plate, and 31 is a movable side die plate. Next, a method for manufacturing an injection-molded product using the mold 1 will be described in detail in the order of steps. That is, first, as shown in FIG. 1, the fixed mold 2 and the movable mold 3 are closed, and then the molten resin is injected into the mold 1 from an injection nozzle (not shown) of the injection molding machine.

The injected molten resin passes through the sprue runner forming portion 5 and is densely filled in the cavity 4. As shown in FIG. 2, a molded product 7 is formed by the filled molten resin.
And the sprue runner 8 is formed. The sprue runner 8 is composed of a sprue portion 81 and a runner portion 82, and the runner portion 82 includes the gate portion 82a and the above-mentioned recessed portion 5.
2b and a columnar protrusion 82b formed of the molten resin.

The columnar protrusion 82b has the same axis as the sprue 81 and protrudes toward the movable die 3 side. When the filling is completed, the fixed mold 2 and the movable mold 3 are opened. Before the fixed mold plate 21 of the fixed mold 2 and the movable mold plate 31 of the movable mold 3 are opened, first, the fixed mold is fixed. After the mold mounting plate 23 and the fixed-side mold plate 21 and the fixed-side mold plate 21 and the runner stripper plate 22 are opened in this order, as shown in FIG. The template 31 is opened.

When the fixed mold 2 and the movable mold 3 are released in this manner, the molded product 7 is moved to the movable side mold plate 31 as shown in FIG.
On the side, sprue runner 8 is runner stripper plate 2
It will be in a state of being attached to each of the two sides. Next, molded product 7
The sprue runner 8 is removed from the mold 1, but the molded product 7 can be taken out from the mold by a projecting pin 11 projecting in the direction of the fixed mold 2 and a taking-out means or the like (not shown) provided at the tip. You can do it. The molded product 7 taken out can be carried to a predetermined place by a carrying means such as a belt conveyor.

On the other hand, as shown in FIG. 2, the sprue runner 8 can be detached from the runner stripper plate 22 by holding the columnar protrusion 82b by the holding means 9 and pulling it out to the movable side mold plate 31 side. ing. That is, according to the injection molding die 1 described above, when the mold is opened, even if the sprue runner 8 rotates about the sprue portion 81 as a central axis due to its own weight of the gate portion 82a,
Since the columnar protruding portion 82b formed of the resin that has entered the concave portion 52b is provided so as to protrude coaxially with the sprue portion 81, the position of the columnar protruding portion 82b does not move and is always at a fixed position with respect to the fixed mold 2. Retained.

Therefore, if the columnar projecting portion 82b is used as the sandwiching portion of the sandwiching means 9 and the sandwiching position of the sandwiching means 9 is set to the position of this columnar projecting portion 82b, the fixed die 2 and the movable die 3 are opened. The sprue runner 8 can be reliably taken out of the mold 1 every time. The injection-molding die concerning the present invention is not limited to the above-mentioned example. For example,
In the above-mentioned embodiment, the cavity 4 is a single-use mold, but it may be a multi-use mold provided with a plurality of cavities.

[0018]

As described above, in the injection molding die according to the present invention, the columnar protrusion having the same axis as the sprue is formed in the sprue runner as the nipping portion of the nipping means.
Even if the sprue runner rotates around the sprue, if the nipping position of the nipping means is set on this columnar protrusion,
Each time the fixed die and the movable die are opened, the sprue runner can be reliably taken out of the die.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of an injection molding die according to the present invention.

FIG. 2 is a cross-sectional view showing a state in which the injection mold of FIG. 1 is opened.

FIG. 3 is a cross-sectional view showing an example of a known injection molding die.

FIG. 4 is a cross-sectional view showing a state where the injection mold of FIG. 3 is opened.

5 is a view of the runner stripper plate of the injection molding die of FIG. 3 viewed from the movable die side.

[Explanation of symbols]

 1 Injection Mold 5 Sprue Runner Molding Part 8 Sprue Runner 9 Clamping Means 51 Sprue Forming Part 52 Runner Forming Part 81 Sprue Part 82 Runner Part 52b Recess 82b Columnar Projecting Part

Claims (1)

[Claims] 1. An injection molding die having a sprue and runner forming portion, wherein a columnar protruding portion coaxial with the sprue forming portion and protruding toward the opposite side of the sprue portion and serving as a holding portion of a holding means when the sprue runner is taken out. An injection mold, wherein a recess formed in the runner portion is provided in a part of the runner forming portion.