JP2000254941A - Mold for injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate cutting, welding, removing or disassembling of a gate and to optimize a size of the gate by continuously variably setting an area of the gate of a resin inlet of a mold for injection molding to form a cavity corresponding to a shape of a molding between a fixed mold and a movable mold. SOLUTION: A gate 4 is slidable in a resin inlet of a cavity of parting surfaces P, L, a height regulating block 7 is slidable in a recess 12 of a fixed mold 1, and two surfaces 71, 72 are oblique to the surfaces P, L. A gate bush 6 is slidable on the surface 71, and a bush position regulating bolt 10 changes a position of the bush 6 through a retaining block 8 on the other surface 72. When the bolt 10 is loosened, the block 8 moves upward to separate from the block 7, the block 7 is moved to the left by pressing a side of the block 7 by a spring 9 to increase a cut area of the gate 4. Thus, a size of the gate can be optimized without processing the gate 4, without removing the old and without disassembling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a mold for injection molding.

[0002]

2. Description of the Related Art In the design of an injection mold (hereinafter sometimes simply referred to as "mold"), the gate dimensions and shape are basically determined based on experience and results, and the mold is manufactured and tested. The mold is removed from the injection molding machine and dismantled, and the trial molding is repeated while shaving or welding the gate, so that the dimensions and appearance of the molded product at the time of molding are good. Was. In particular, when molding a plurality of products with different shapes at the same time, in order to find conditions that do not cause appearance defects such as burrs or burns for each product, the conditions for basically filling the cavities of each product at the same time Even if the dimensions and shape of the gate satisfying the above conditions are obtained, the optimal gate dimensions and shape may differ if the characteristics of the resin used, such as color change, change. In addition, the trial and error of repeated trial molding while shaving the gate part or building up by welding so as to obtain the optimal dimensions and shape leads to an increase in die manufacturing costs. I was

In the case of simultaneously molding a plurality of products having different shapes, depending on the amount of an order, the cost may be increased by filling a cavity corresponding to an unnecessary product shape or by discarding the obtained molded product. It was connected.

As one means for solving such a problem, as described in Japanese Patent Application Laid-Open No. 63-5538, it is possible to make the gate nestable and replaceable. It is also possible to find the shape relatively easily.

[0005]

However, in the above-mentioned method, it is necessary to prepare a large number of nests having different shapes, and fine adjustment is performed by shaving the gate portion or welding. It did not necessarily lead to cost reduction.

The present invention solves the above-mentioned problems, and eliminates the need to cut or weld the gate portion, and to optimize the gate dimensions without removing the mold from the injection molding machine and dismantling it. An object of the present invention is to provide an easy injection mold.

[0007]

Means for Solving the Problems According to claim 1,
The “invention 1”) is a mold for injection molding in which a cavity corresponding to the shape of a molded product to be molded is formed between a fixed mold and a movable mold. The cross-sectional area of the gate portion, which is the resin injection port, is continuously variable.

According to a second aspect of the present invention, there is provided an injection mold according to the present invention, wherein a gate bush is provided in a gate through hole so as to be able to advance and retreat in the injection mold according to the present invention. A bush position adjustment bolt is provided on the outer peripheral surface of the fixed type or the movable type, and based on the displacement of the tip of the bush position adjustment bolt, by changing the position of the gate bush, the cross-sectional area of the gate portion is continuously variable. Is what is being done.

In the present invention 1 or 2, the cross-sectional area of the gate portion may be zero. By doing so, it is possible to prevent the resin from flowing into the cavity corresponding to the unnecessary product shape.

(Function) In the injection molding die of the present invention 1, the gate section, which is a resin injection port into the cavity, has a continuously variable cross-sectional area, so that the gate section can be scraped off. Optimized gate dimensions without the need for welding or removing the mold from the injection molding machine and dismantling

In the injection molding die according to the second aspect of the present invention, a gate bush is provided in the gate through hole so as to be able to advance and retreat, and a bush position adjusting bolt is provided on the outer peripheral surface of the fixed or movable die. Since the position of the gate bush is changed based on the displacement of the tip of the bolt, the cross-sectional area of the gate portion can be easily changed continuously while the mold is mounted on the injection molding machine.

[0012]

Embodiments of the present invention will be described below in more detail with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of the injection mold of the present invention 1 and 2, and FIG.
Is a molded product (including a solidified resin filled in the gate and the runner portion) molded using the injection mold of FIG.
It is a perspective view of.

In FIG. 1, 1 is a fixed type, 2 is a movable type,
Reference numeral 3 denotes a cavity, 4 denotes a gate, 5 denotes a runner, 6 denotes a gate bush, and 7 denotes a height adjustment block. As shown in FIG. 1, a cavity 3 corresponding to the shape of a molded article to be molded is formed between a fixed mold 1 and a movable mold 2 in the injection molds of the present inventions 1 and 2. .

In order to obtain a molded product using the injection mold, a resin melted from a nozzle of an injection molding machine (not shown) is supplied to a runner via a sprue (not shown) provided in the fixed mold 1. 5 is injected into the cavity 3 through the gate 4. As a result, a molded product 3a corresponding to the shape of the cavity 3 is obtained as shown in FIG.
The resin solids 4a, 5a corresponding to the shape of the runner 5 are released.

FIG. 3 is a sectional view taken along the line XX of the injection mold of FIG. 1, and FIG. 4 is an enlarged perspective view showing a main part thereof. As shown in FIG. 3, the gate 4 is a side gate, and the parting surface P.P. L. It is provided above and serves as a resin injection port for the cavity 3 (FIG. 1). Gate 4
Has a configuration in which a gate bush 6 is provided to be able to advance and retreat in a gate through hole.

On the other hand, the height adjusting block 7 is
Are slidable (in the left-right direction in FIG. 3) in the concave portion 12 provided at the parting surface P. L. And inclined surfaces 71 and 72 are formed. The gate bush 6 is slidably provided on one of the inclined surfaces 71.
The gate bush 6 includes a base 6a that slides on the inclined surface 71.
And a pin portion 6b that can move back and forth in the gate through-hole.
Consists of

A bush position adjusting bolt 10 is provided on another inclined surface 72 of the height adjusting block 7 via a holding block 8, and the gate is adjusted based on the displacement of the tip of the bush position adjusting bolt. The position of the bush 6 is changed.

The gate bush 6 and the bush position adjusting bolt 10 are restrained from moving in a direction other than the vertical direction by the cover plate 11. The cover plate 11 is fixed to the parting surface P. L. By removing the cover plate 11, the gate bush 6, the height adjusting block 7, the holding block 8, and the bush position adjusting bolt 10 can be replaced.

When the bush position adjusting bolt 10 is tightened, the holding block 8 moves downward and pushes the inclined surface 72 of the height adjusting block 7. And the height adjustment block 7
Is moved leftward in FIG. Then, the gate bush 6 slidably provided on the inclined surface 71 is pushed and moves upward, and the sectional area of the gate 4 decreases. In this case, when the gate bush pin portion 6b contacts the movable mold 2, the gate 4 is closed (FIG. 5). At this time, a spring 9 is provided between the gate bush pedestal 6a and the cover plate 11, and the pin 6b of the gate bush relieves the pressure in contact with the movable mold 2, and the bush position adjusting bolt It prevents 10 overtightening.

On the other hand, when the bush position adjusting bolt 10 is loosened, the holding block 8 moves upward and separates from the height adjusting block 7. Then, by the restoring force of the spring 9,
The pin portion 6b of the gate bush is separated from the movable mold 2, and the cross-sectional area of the gate 4 increases. Then, the inclined surface 71 of the height adjustment block 7 is pushed, and the height adjustment block 7 is
The inclined surface 72 comes into contact with the holding block 8 in the middle right direction and stops (FIG. 6).

When the mold is closed, the top of the bush position adjusting bolt 10 is housed in a recess 21 provided on the parting surface of the movable mold 2.
In addition, it is easy to tighten or loosen the mold while it is open.

FIG. 7 is a sectional view showing another example of the injection mold of FIG. 1, and FIG. 8 is an enlarged perspective view showing a main part thereof, which is substantially the same as FIGS. Parts that are equivalent are denoted by the same reference numerals and description thereof is omitted.

In FIGS. 7 and 8, the spring 9 is fixed
The gate bush 61 is provided between the height adjustment block 7 and the height adjustment block 7, and can be moved vertically along a guide rail 62 provided on the inclined surface 71 of the height adjustment block 7. Except for the above, it is the same as FIGS.

7 and 8, when the bush position adjusting bolt 10 is tightened, the holding block 8 moves downward and pushes the inclined surface 72 of the height adjusting block 7. Then, the height adjusting block 7 is moved leftward in FIG. Then, it moves upward along the guide rail 62 provided on the inclined surface 71, and the cross-sectional area of the gate 4 decreases. At this time, a spring 9 provided between the fixed die 1 and the height adjusting block 7 prevents the bush position adjusting bolt 10 from being excessively tightened.

On the other hand, when the bush position adjusting bolt 10 is loosened, the holding block 8 moves upward and separates from the height adjusting block 7. Then, by the restoring force of the spring 9,
The side surface of the height adjustment block 7 is pushed, and the height adjustment block 7 moves rightward, and the cross-sectional area of the gate 4 increases.

[0026]

According to the first aspect of the present invention, as described above, there is no need to cut or weld a gate portion.
It is easy to optimize the gate dimensions without removing the mold from the injection molding machine and dismantling it. The present invention 2
Because of the above, the cross-sectional area of the gate portion can be easily changed continuously while the mold is mounted on the injection molding machine.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one example of an injection mold according to the present inventions 1 and 2.

FIG. 2 is a molded article molded using the injection mold of FIG. 1 (including a solidified resin filled in a gate and a runner).
It is a perspective view of.

FIG. 3 is a cross-sectional view of the injection mold of FIG. 1 taken along line XX.

FIG. 4 is an enlarged perspective view showing a main part of FIG. 3;

5 is a cross-sectional view showing a state where a gate of the mold shown in FIG. 3 is closed.

FIG. 6 is a cross-sectional view showing a state where a gate of the mold shown in FIG. 3 is opened.

FIG. 7 is a cross-sectional view showing another example of the injection molds of the present inventions 1 and 2.

FIG. 8 is an enlarged perspective view showing a main part of FIG. 7;

[Description of Signs] 1 Movable mold 2 Fixed mold 3 Cavity 3a Molded product 4 Gate 6 Gate bush 10 Bush position adjusting bolt

Claims (2)

[Claims] 1. An injection molding die in which a cavity corresponding to the shape of a molded product to be molded is formed between a fixed die and a movable die. A mold for injection molding characterized by being continuously variable. 2. A gate bushing is provided in the gate through-hole so as to be able to advance and retreat, and a bush position adjusting bolt is provided on an outer peripheral surface of a fixed type or a movable type, and based on displacement of a tip portion of the bush position adjusting bolt. 2. The injection molding die according to claim 1, wherein the gate section cross-sectional area is continuously variable by changing the position of the gate bush.