JPH1170550A - Gate bush for mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the production cost of a gate bush to a large extent by forming the gate bush from a sintered product. SOLUTION: A gate bush 1 is arranged between the runner 3 and cavity 4 of a resin mold 2 so as to be formed so as to have a gate for ejecting a molten resin R into the cavity 4 and produced by sintering. As the material of the gate bush 1, a ceramics powder or a metal powder is used. A core 11 is arranged in a fixed template 10 and the gate bush 1 is arranged to the core 11 and a movable template 12 is constituted so as to be freely separable, openable, closable and movable with respect to the fixed template 10 so as to provide the cavity 4. At a time of mold closing, the molten resin R is passed through the gate 5 of the gate bush 1 through a runner 3 to be injected into the cavity 4 to mold a molded product and the mold is opened to take out the molded product. By this constitution, the production cost of the gate bush 1 can be reduced to a large extent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold gate bush used for a resin molding mold, for example.

[0002]

2. Description of the Related Art Conventionally, as a gate bush for a mold of this type, there has been known a gate bush for a high-speed steel manufactured by cutting machining and electric discharge machining, or of a complicated shape by electroforming with a nickel alloy. ing.

[0003]

However, in the case of the above-mentioned conventional structure, high-speed steel is manufactured by machining, electric discharge machining or electroforming, so that cutting and electric discharge machining are difficult and the electroforming process is complicated. In addition, the production cost is extremely high, and the production cost of the mold is apt to increase. The gate bush of the conventional structure has relatively high thermal conductivity, and therefore, the cooling rate of the molten resin. This has the disadvantage that the gate is sealed by the molten resin, which makes it difficult to control the internal pressure of the cavity.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve such inconvenience. Among the present invention, the invention described in claim 1 is directed to a resin molding die runner and a cavity. And a mold gate bush having a gate as a gate from which molten resin is injected into the cavity, wherein the gate bush is made of a sintered product. is there.

[0005]

1 to 4 show an embodiment of the present invention. FIGS. 1 to 3 show a first embodiment and FIG. 4 shows a second embodiment.

In the first embodiment shown in FIGS. 1 to 3, reference numeral 1 denotes a gate bush, in this case, a pinpoint gate bush, which is disposed between a runner 3 and a cavity 4 of a resin molding die 2, The molten resin R is formed with a gate 5 serving as a gate for the molten resin R to be injected into the cavity 4. The gate 5 includes a tapered throat portion 5a and an injection portion 5b. The gate bush 1 having the gate 5 is sintered. Has been produced.

As a sintered material for the gate bush 1, ceramic powder, metal powder, composite material powder, for example, powders of alumina, zirconia, aluminum nitride, silicon nitride, etc. are used. It is determined in consideration of conductivity, heat resistance, and the like.

In this case, as a mold structure, a locating ring 7, a runner stripper plate 8 and a runner lock pin 9 are disposed on the fixed side mounting plate 6, and the fixed side template 10 is mounted on the runner stripper plate 8. The runner 3 is formed between the stripper plate 8 and the fixed template 10, and the nest 11 is attached to the fixed template 10.
Is arranged, and the gate bush 1 is arranged in the nest 11,
The movable template 12 is fixed to the fixed template 10 with the cavity 4 present.
It is configured so that it can be freely moved in and out of the door.

Since the first embodiment has the above structure, as shown in FIG. 3, when the mold is closed, the molten resin R passes through the gate 5 of the gate bush 1 via the runner 3 as a runner. Injected into the cavity 4, the molded product is molded by the cavity 4, and the molded product is removed by opening the mold. At this time, since the gate bush 1 is manufactured by sintering, the mass production effect is also reduced. Together with this, the manufacturing cost of the gate bush 1 can be significantly reduced, the manufacturing cost of the mold can be reduced accordingly, and a sintered product having a low thermal conductivity can be obtained by selecting a sintering material. Therefore, since the cooling rate of the molten resin near the injection port is delayed, it is possible to prevent the gate 5 from being sealed by the molten resin and to control the internal pressure of the cavity 4 well. It can, much can be improved the stability and workability of the molding, moreover sinter has high resistance abrasion, thus it is possible to durable use of the mold.

FIG. 4 shows another example of the structure of the gate bush 1. In this case, the gate bush 1 is made of a sintered product and has a protruding portion 1a formed at the tip of the gate bush 1. ing.

In the second embodiment, the same operation and effect as in the first embodiment can be obtained.

It should be noted that the present invention is not limited to the above-described embodiment, and the shapes and structures of the gate bush 1 and the gate 5 are designed by appropriately changing.

[0013]

As described above, according to the first aspect of the present invention, since the gate bush is manufactured by sintering, the manufacturing cost of the gate bush is greatly reduced due to the mass production effect. Can be reduced, the production cost of the mold can be reduced accordingly, and a sintered product having a low thermal conductivity can be obtained by selecting a sintering material. Since the cooling speed of the molten resin is delayed, the gate can be prevented from being sealed by the molten resin, the internal pressure of the cavity can be controlled well, and the stability and workability of the molding process can be improved accordingly, and The sintered product has high abrasion resistance, so that the mold can be used durably.

As described above, the intended purpose can be sufficiently achieved.

[Brief description of the drawings]

FIG. 1 is an overall side view of a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of the first embodiment of the present invention.

FIG. 3 is a sectional view of a mold in a used state according to the first embodiment of the present invention.

FIG. 4 is an overall side view of a second embodiment of the present invention.

[Explanation of symbols]

 R Molten resin 1 Gate bush 2 Mold for resin molding 3 Runner 4 Cavity 5 Gate

Claims (1)

[Claims] 1. A gate bush which is disposed between a runner and a cavity of a resin molding die and has a gate as a gate for injecting molten resin into the cavity,
The gate bush for a mold, wherein the gate bush is made of a sintered product.