JPH1158451A - Synthetic resin mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase heat dissipation to an insert and a mold to restrain the temperature rise of an insert part and improve degating by a method wherein a gap formed between the insert and the mold is filled with heat transfer promoting agent. SOLUTION: A secondary spool 1 of a pin point gate system synthetic resin mold is constituted of a mold 2 and an insert 3 while the insert 3 is provided with a tip end unit 4, a cylindrical unit 5 and a flange unit 6. In such an insert 3, the insert 3 is constituted so as to be positioned optimally in the mold 2 through the engagement between the tip end unit 4 and the mold 2 as well as the flange unit 6. In this case, a gap 7 is formed usually between the mold 2 and the insert 3, however, the gap 7 is filled with a heat transfer promoting agent in this case to constitute the mold 2 and the insert 3 as an integrated body having no gap under apparent heat transfer condition. The heat transfer promoting agent is a semi-solid substance, excellent in heat transfer characteristics, and heat transfer characteristics between substances can be improved remarkably by filling the gap 7 with the same substance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin mold, and more particularly to a technique for improving gate cutout and shortening a molding cycle of a pinpoint gate type synthetic resin mold in which a secondary spool is formed by nesting.

[0002]

2. Description of the Related Art A conventional general pinpoint gate type synthetic resin mold is shown, for example, in FIG. As shown in the figure, the synthetic resin mold 10 includes a fixed mold 11 and a movable mold 12, and the fixed mold 11 is provided via a plate 14 on which only a runner called a runner stripper plate is disposed. The movable mold 12 is mounted on a movable mold mounting plate 15 via a spacer block 16, and the fixed mold 11 and the movable mold 12 are fixed to each other. A cavity 17 for a molded product A having a required shape is formed by the mold 12, and a spool runner 19 and a secondary spool 2 are formed so that molten resin from an injection molding machine is injected into the cavity 17.
0 is provided.

The tip of the secondary spool 20 of such a pinpoint gate type synthetic resin mold 10 has a diameter of 0.3.
It is connected to the cavity 17 for the molded product A by a circular gate of about 1.2 mm, and when the synthetic resin mold 10 is opened, the communicating part is torn off and the gate is automatically cut off, and the spool runner 19 and the spool runner 19 are connected. The molded article A is taken out separately. Therefore, it is common that post-processing of the gate is not performed, and it is suitable for multi-piece molding of the molded product A.

[0004]

However, the above-mentioned conventional pinpoint gate type synthetic resin mold has the following drawbacks.

Usually, the secondary spool 20 of the synthetic resin mold 10 of the pinpoint gate type is of a nested type as shown in FIG. 2, and sometimes direct engraving is observed. And a nest 22.
The nest 22 of the secondary spool 20 has a tip portion 24 and a trunk portion 25.
In the case of such a nest 22, it is difficult to fit the mold 21 and the nest 22 over the entire length in terms of working.
4 is fitted into the hole of the mold 21,
5 is generally formed to escape. Therefore, a gap 2 formed between the mold 21 and the insert 22 is formed.
7 serves as a heat insulating layer, and the temperature of the insert 22 rises due to heat radiation from the molten synthetic resin in the secondary spool 20 portion. As a result, depending on the molding material, the cooling of the portion of the secondary spool 20 is delayed, so that the molding cycle is lengthened or a gate disconnection failure occurs. Further, there are many defective products such as the secondary spool 20 extending due to the mold opening operation at the time of release.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve such a conventional problem by providing a pinpoint gate type synthetic resin mold nested secondary spool with a gap between the mold and the nest. By filling a heat transfer promoter into the mold, or inserting a fitting ring made of a material with high thermal conductivity, the heat radiation from the nest to the mold is increased, and the temperature rise in the nest is suppressed to reduce the gate. Improve cutting,
It is to shorten the molding cycle.

[0007]

According to the present invention, there is provided a synthetic resin mold according to the present invention, comprising: a pin-point gate type synthetic resin mold in which a secondary spool is formed by nesting; It is characterized in that a heat transfer promoter is filled in a gap formed between the mold and the mold.

Further, according to the synthetic resin mold of the present invention, in a pinpoint gate type synthetic resin mold in which a secondary spool is formed by nesting, a thermal conductivity is provided in a gap formed between the nest and the mold. By inserting a fitting ring made of a large material, the temperature rise of the nest portion is suppressed, and various problems are solved.

Further, the synthetic resin mold of the present invention is characterized in that the heat transfer promoter is a semi-solid substance having excellent heat transfer properties, and the substance is applied.

Furthermore, the synthetic resin mold of the present invention is characterized in that the material having a high thermal conductivity is a copper-based material.

Other objects and features of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings.

[0012]

FIG. 1A is a cross-sectional view of a secondary spool portion of a pinpoint gate type synthetic resin mold according to a first embodiment of the present invention. The secondary spool 1 of the pinpoint gate type synthetic resin mold of the present invention comprises a mold 2 and a nest 3, and the nest 3 is formed by the tip 4, the body 5, and the collar 5 for the same reason as described above. And a part 6. In such a nest 3, the nest 3 is configured to be appropriately positioned in the mold 2 by fitting the end portion 4 with the mold 2 and the collar 6. At this time, usually, a gap 7 is formed between the mold 2 and the insert 3. In the present invention, the gap 7 is filled with the heat transfer promoter 8 a and the mold 2 is filled.
The apparent heat transfer state between the nest 3 and the nest 3 is configured as an integral one without any gap. The heat transfer enhancer 8a is a semi-solid material having excellent heat transfer characteristics. By filling or applying the same material to the gap 7, heat transfer characteristics between the materials are greatly improved.

Therefore, the secondary spool 1 is formed during the forming process.
The heat of the molten synthetic resin released from the synthetic resin in the portion to the insert 3 does not stay in the insert 3 as in the synthetic resin mold having the conventional structure, but is smoothly transmitted to the mold 2 and radiated. Is done.

As a result, the temperature of the nest 3 during molding is relatively constant, the cooling state of the synthetic resin in the secondary spool 1 is stabilized, and the gate cut at the tip of the secondary spool 1 is improved. In addition, the extension of the secondary spool 1 due to the mold opening operation when releasing the molded product is prevented. Further, since the heat radiation from the nest 3 to the mold 2 becomes smooth, the cooling time until the synthetic resin in the secondary spool 1 becomes a solidified state that can be taken out of the molten state is shortened, and the molding cycle is shortened. Is also very effective.

On the other hand, FIG. 1B shows a cross section of a secondary spool portion of the pinpoint gate type synthetic resin mold of the present invention. In this embodiment, heat transfer is performed in the first embodiment. In the gap 7 between the mold 2 and the insert 3 filled with the accelerator 8a,
By inserting the fitting ring 8b made of a material having high thermal conductivity, for example, a copper-based material, the same effect as in the first embodiment can be obtained. The fitting ring 8b is a cylindrical ring, and the inner diameter portion is fitted with the outer diameter portion of the nest 3 forming the secondary spool portion, and the outer diameter portion is fitted to the mold 2 in order to incorporate the nest 3. It is designed to fit with the processed inner diameter portion of the engraving.

[0016]

As described above, according to the present invention, in a pinpoint gate type synthetic resin mold in which a secondary spool portion is formed by nesting, a gap portion formed between the nesting and the mold is provided. The heat of the synthetic resin released from the melted synthetic resin in the secondary spool part into the nest by filling the heat transfer promoter into the heat sink or inserting a fitting ring made of a material with high thermal conductivity It is possible to satisfactorily transmit the heat from the nest to the mold and radiate the heat without squeezing, thereby preventing a rise in the temperature of the nest portion.

As a result, it is possible to improve the extension of the molding cycle due to the cooling delay of the secondary spool portion and the gate disconnection failure at the tip of the secondary spool portion, which have been caused by the rise in the temperature of the nest portion. The defect that the secondary spool portion is extended at the time can also be preferably improved at the same time.

[Brief description of the drawings]

FIG. 1 is a sectional view of a secondary spool portion of a synthetic resin mold according to the present invention.

FIG. 2 is a sectional view of a secondary spool portion of a conventional synthetic resin mold.

FIG. 3 is a schematic view of a pinpoint gate type synthetic resin mold.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 secondary spool 2 mold 3 nest 4 tip 5 body 6 flange 7 gap 8 a heat transfer promoter 8 b fitting ring 10 synthetic resin mold 11 fixed mold 12 movable mold 13 fixed mold Mounting plate 14 Plate 15 Movable mold mounting plate 16 Spacer block 17 Cavity 19 Spool runner 20 Secondary spool

Claims (4)

[Claims] 1. A pinpoint gate type synthetic resin mold in which a secondary spool portion is formed by nesting, wherein a gap formed between the nesting and the mold is filled with a heat transfer promoter. Synthetic resin mold. 2. The synthetic resin mold according to claim 1, wherein the heat transfer accelerator is a semi-solid material having excellent heat transfer characteristics, and the material is applied. 3. A pinpoint gate type synthetic resin mold in which a secondary spool portion is formed by nesting, wherein a gap formed between the nesting and the mold is formed by a fitting ring made of a material having high thermal conductivity. A synthetic resin mold characterized by inserting a mold. 4. The synthetic resin mold according to claim 3, wherein the material having a high thermal conductivity is a copper-based material.