JP3140484B2 - Injection mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection mold.
In particular, the present invention relates to an injection mold capable of shortening a cooling time.

[0002]

2. Description of the Related Art As a conventional technique, a mold is often cooled by installing a temperature control tube in a mold plate of the mold and filling the temperature control tube with a cooling medium such as water or oil. Then, the amount of heat brought into the mold by the injected molten resin is taken out of the mold by the medium in the temperature control tube through the cavity or the mold plate of the mold.

Further, in the invention described in Japanese Patent Application Laid-Open No. 60-131217, for example, a flow path for flowing a predetermined gas is provided around a spool, and air or other gas flows as cooling gas through the flow path. A method has been proposed in which the temperature of the spool is controlled by adjusting the flow rate thereof, and the solidification of the resin in the spool is optimized.

[0004]

However, the prior art described above and the invention described in Japanese Patent Application Laid-Open No. Sho 60-131217 have the following disadvantages.

That is, in the above-mentioned conventional technique, although the cavity for molding the molded product is sufficiently cooled, the portion where the spool and the runner intersect (hereinafter referred to as the intersecting portion) is cooled by the mold plate. Only.

[0006] Further, since the crossing portion is generally thicker,
Cooling takes time.

Therefore, although the cooling of the cavity has been completed, the cooling of the intersection has not been completed, and the spool and the runner are separated when the molded product is taken out from the mold. Is generated.

Therefore, the cooling time has to be extended,
The cycle time is extended.

In the invention described in Japanese Patent Application Laid-Open No. Sho 60-131217, a method of cooling by flowing a gas is required, and a gas flow path is required, so that the size of a mold is increased.

When the cooling gas is other than air, a space such as a cylinder is required, which complicates the operation.

Further, when the cooling temperature is controlled by the gas flow rate, the heat exchange rate is lower than that of a liquid or a solid, so that the reliability of the temperature control is low.

Therefore, the present invention has been developed in view of the above-mentioned drawbacks, and promotes cooling of the intersecting portion by a simple structure without hindering the molding of the molded article, thereby reducing the cycle time of the molded article. An object of the present invention is to provide a mold for injection molding that can be shortened.

[0013]

According to the injection molding die of the present invention, heat is transferred to a spool bush and a die base around an intersection where a spool and a runner intersect with each other. Body arranged.

That is, according to the present invention, since the heat transfer member having a higher thermal conductivity than steel is provided on the spool bush and the mold base around the intersection where the spool and the runner intersect, the cooling of the intersection can be achieved. Promoted.

[0015]

[Embodiment 1] First, before describing a specific embodiment of the present invention, an outline of the present invention will be described. FIG. 1 is a conceptual diagram of the present invention.

Reference numeral 1 denotes an injection mold. The injection mold 1 is kept at a constant temperature (about 50 ° C. to 130 ° C. depending on the material) during cooling after filling with resin.

A heat transfer body 5 having a higher thermal conductivity than steel is provided on a spool bush 3 and a mold base 4 around an intersection 2 where the spool and the runner intersect with each other in the injection mold 1. Has been established.

The solidification of the filled resin proceeds by transferring the heat of the resin to the mold. At this time, the intersection 2 between the spool and the runner has a large thickness, so that a heat pool is generated. However, the transfer of heat is promoted by the heat transfer member 5 disposed around the intersecting portion 2, and the cooling of the intersecting portion 2 and the resin pool 6 can be accelerated.

Next, specific embodiments of the present invention will be described with reference to the drawings. 2 and 3 show this embodiment. FIG. 2 is a half sectional view, and FIG. 3 is a partially enlarged sectional view.

Reference numeral 11 denotes an injection mold. A temperature control tube 14 is provided in the fixed mold plate 12 and the movable mold plate 13 of the injection mold 11, and flows through the temperature control tube 14. The medium can be maintained at a constant temperature (about 50 ° C. to 130 ° C. depending on the material) depending on the medium.

A spool bush 15 for forming a resin flow portion (spool portion) is formed on the fixed side mold plate 12 with a bolt 1.
6 fixed.

As shown in FIG. 3, the spool bush 15 has at least the brass (heat conductivity 95) having a higher heat conductivity than steel at the runner 16 side (opposite to the spool opening 17).
Kcal / m.hr. ° C.) is fixed by a screw 19 with a cylindrical heat transfer body 18.

A cylindrical heat transfer body 21 made of brass similar to the heat transfer body 18 is fixed to the movable mold plate 13 at a position around the intersecting portion 20 with screws 22.

The resin is injected from the spool port 17 of the injection mold 11 having the above configuration. The resin flows into the spool bush 15, the runner 16, and the cavity 23 for molding the molded product. After the pressure is applied, the resin is cooled by the thermal conductivity of the surface of the mold. At this time,
The heat transfer is promoted by the heat transfer members 18 and 21 provided around the spool 20 and the runner, which are generally hard to be cooled due to the thick wall, and the cooling is completed in a short time. .

According to this embodiment, the cooling time required for removal can be shortened, and the molding cycle can be shortened.

[0026]

[Embodiment 2] In this embodiment, the materials of the heat transfer members 18 and 21 in the first embodiment are made of the same material and have the same heat conductivity.
The difference is that aluminum is twice as high (thermal conductivity: 196 Kcal / m.hr. ° C.), and the other components have the same configuration, and the description of the configuration is omitted.

In this embodiment, cooling is promoted by using an aluminum heat conductor having a high thermal conductivity.

According to the present embodiment, it is possible to cope with a thick intersection between the spool and the runner.

[0029]

Embodiment 3 In this embodiment, the material of each of the heat transfer members 18 and 21 in the first embodiment is black zinc (a heat conductivity of 96 Kcal / m.
hr. ° C.), and the other components have the same configuration, and a description of the configuration will be omitted.

The black zinc used as the material of the heat transfer body in this embodiment has higher corrosion resistance than brass or aluminum. Therefore, there is little corrosion by gas.

According to this embodiment, the life of the heat transfer body can be extended.

(Reference Example) FIGS. 4 and 5 are partial sectional views showing a reference example.

The injection molding die 31 of the reference example is formed of brass having a higher thermal conductivity than steel and is provided with a protruding pin 32 that is slidable up and down below the intersection portion 20 in the first embodiment. I have. The protruding pin 32 has a cylinder 33 set at the bottom thereof, and is formed in a narrow shape near the upper end, and is provided so that the upper end can enter the intersecting portion 20. Have the same configuration, and the same components are denoted by the same reference numerals and description of the configuration will be omitted.

The injection mold 31 having the above structure is
Immediately after the cavity 23 is filled with the resin and the gate is sealed, the cylinder 33 is operated to raise the tip of the protruding pin 32 to the intersection 20 where the spool and the runner intersect.

According to the reference example, not only the heat pool in the crossing portion 20 is cooled through the resin having poor thermal conductivity, but also the forced cooling can be performed.

The protrusion pin 32 of the reference example is entirely formed of brass, but is not limited to this.
Only the tip can be made of brass or other material having excellent heat conductivity.

[0037]

Embodiment 4 FIG. 6 is a partial sectional view showing this embodiment.

The injection molding die 41 of this embodiment is different from the temperature control tube 14 of the injection molding die 11 of the first embodiment, and is further provided with an auxiliary temperature control tube close to the heat transfer members 18 and 21. 42
The other configuration is the same, and the same components are denoted by the same reference numerals and description of the configuration is omitted.

In this embodiment, the heat absorbed from the resin is transferred from the heat transfer members 18 and 22 to the fixed mold plate 12 and the movable mold plate 1.
3 and is absorbed by the auxiliary temperature control tube 42.

According to the present embodiment, cooling can be promoted without accumulating heat in the heat transfer members 18 and 22.

[0041]

As described above, according to the injection molding die of the present invention, the intersection of the spool and the runner is formed without increasing the dimensions of the die and without complicating the operation. By being able to cool faster than the product, the spool and the runner are not separated during removal of the molded product, and stable molding can be performed.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating the present invention.

FIG. 2 is a half sectional view showing the first embodiment.

FIG. 3 is a partially enlarged sectional view showing the first embodiment.

FIG. 4 is a partial sectional view showing a reference example.

FIG. 5 is a partial sectional view showing a reference example.

FIG. 6 is a partial sectional view showing a fourth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection molding die 2 Intersection 3 Spool bush 4 Die base 5 Heat transfer body

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) B29C 45/26-45/44 B29C 45/73 B29C 33/00-33/76

Claims (1)

(57) [Claims] 1. A mold for injection molding, wherein a heat conductor having a higher thermal conductivity than steel is provided on a spool bush and a mold base around an intersection where a spool and a runner intersect.