JPH09136325A - Mold apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the temperature of a mold for blow molding promptly and to improve the quality and productivity of moldings. SOLUTION: A chamber 3 is installed on the back side of the cavity surface 2 of a mold main body 1. A pipe 4 penetrating the chamber 3 is connected interchangeably to a water supply pump 5 and a boiler 6. Moreover, the chamber 3 is connected with a vacuum pump 9 through a pipe 8. When the mold main body 1 is cooled, cooling water is spouted uniformly into the chamber 3, and simultaneously the pressure of the chamber 3 is reduced to a prescribed pressure by a vacuum pump 9. When the mold main body is heated, steam is supplied from a boiler 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold device suitable for use in blow molding, for example.

[0002]

Blow molding is a method in which a heat-softened synthetic resin parison is pressed against the surface of a mold to mold it. However, it does not completely melt the resin material as in injection molding, and the molding pressure is also high. Relatively low. Therefore,
Although the surface shape is complicated, it is difficult to mold, and it is also difficult to transfer a pattern such as grain to the surface of the molded product clearly.

In order to solve this, micropores (deaeration pores)
Although many methods are provided to make it easier for air and gas to escape between the mold and parison, the mold strength decreases due to hole processing, and the initial performance is maintained by preventing clogging of minute holes. There is a problem that maintenance is required to do so. Besides this, after the parison is in close contact with the mold,
There is a method of heating the mold again to soften the parison and improve the shape transfer performance.

[0004]

However, the latter method has a problem in that the number of steps for heating and cooling the mold is increased, and the molding time is lengthened.

Therefore, an object of the present invention is to improve the molding quality and productivity by making it possible to quickly control the temperature of the mold.

[0006]

In order to solve this problem, the following mold device was created. That is, the invention according to claim 1 is a mold main body in which a chamber is provided on the back side of the cavity surface, a cooling liquid feeding means for feeding a cooling liquid into the chamber, and a decompression means for decompressing the inside of the chamber. It is characterized by having and.

Therefore, the mold is cooled by sending an appropriate amount of the cooling liquid into the chamber and simultaneously depressurizing the inside of the chamber to promote vaporization (phase transformation) of the cooling liquid.
At this time, since the heat of vaporization is used, a relatively small amount of cooling liquid can be used for rapid and uniform cooling.

According to a second aspect of the present invention, in the mold apparatus according to the first aspect, the deaeration hole opening on the cavity surface communicates with a deaeration groove formed on the back surface of the cavity surface, and The degassing groove is covered with a lid member and plated on the lid member to fix the lid member to the mold body.

As described above, it is easy to form a degassing passage in the chamber, separated from the chamber. Then, for example, during blow molding, it becomes easy to guide the air or gas between the cavity surface and the parison to the outside of the mold via the passage.

[0010] The invention of claim 3 is based on claim 1 or 2.
The mold apparatus described above is characterized in that it is provided with steam feed means for feeding heating steam into the chamber.

That is, the chamber is commonly used for both cooling and heating.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing a mold device for blow molding, FIG. 2 is an enlarged view of portion A of FIG. 1, and FIG. 3 is a diagram for explaining a deaeration hole and a deaeration groove of the mold device. It is a partially broken perspective view. In FIG. 1, reference numeral 1 denotes one of the pair of mold bodies, which is made thin by casting or electroforming.
The mold body 1 is provided with a closed chamber 3 on the back side of the cavity surface 2.
Is penetrating. The pipe 4 is provided with a water supply pump 5 as a cooling liquid feeding means and a boiler 6 as a steam feeding means via valves and the like.
Is connected so that the predetermined amount of water or steam can be evenly injected into the chamber 3 through the plurality of discharge ports 4a. Further, the chamber 3 is provided with a drain portion 7 for both drainage and deaeration, and a pipe 8
And a vacuum pump 9 which is a pressure reducing means via a valve and the like.

A large number of deaeration holes 2a having a small diameter are formed on the cavity surface 2 of the mold body 1. The deaeration hole 2a is
As shown in FIGS. 2 and 3, the cavity surface 2 is penetrated, and the back surface 2b of the cavity surface is formed with deaeration grooves 2c at positions corresponding to the deaeration holes 2a so as to communicate the deaeration holes 2c. There is. Although only one deaeration groove 2c is shown in FIG. 1 as a representative example, in actuality, a plurality of rows may be provided if necessary.

Then, referring to FIG. 2, the deaeration groove 2c is provided with a lid member,
Specifically, the tape 10 is covered with a metal foil such as aluminum or a net-shaped narrow tape 10, and then plated with nickel, chromium, iron or the like to form a plating layer 11, and the tape 10 is molded into a mold body. Fix to 1. The degassing passage thus formed is completely partitioned from the chamber 3 and communicates with the atmosphere on the outer surface of the mold body 1.

Next, the operation of the mold device configured as described above will be described. At the time of blow molding, in order to cool the mold body 1, the cooling water sent by the water supply pump 5 is jetted into the chamber 3 from the discharge port 4a, and at the same time, the vacuum pump 9 is operated to move the inside of the chamber 3 to a predetermined position. Reduce pressure to pressure. In this case, the amount of water injected is set according to the heat capacity of the mold body 1 and the shape of the cavity, and the cooling water is evenly sprayed into the chamber 3 so as to form a uniform water film on the heat transfer surface. Further, the suction amount by the vacuum pump is set so that the cooling water is efficiently vaporized.

That is, the above-mentioned cooling means applies the principle of vacuum evaporative cooling, and a uniform cooling effect without temperature unevenness can be obtained by heat transfer accompanied by phase transformation (vaporization) of water.
As a result, the molding quality is improved. Further, productivity can be improved because rapid cooling is possible. Further, since the amount of cooling water is smaller than that in the conventional heat exchange of, for example, a water cooling type, it is possible to reduce the weight of the mold and save water.

On the other hand, when heating the die body 1, high temperature steam sent from the boiler 6 is injected into the chamber 3 through the discharge port 4a. In this case, since the chamber 3 and the pipe 4 are used for both cooling and heating, the structure of the mold device is simplified.

During the blow molding, the air and the generated gas remaining between the cavity surface 2 of the mold body 1 and the parison are guided to the degassing grooves 2c from the degassing holes 2a and completely partitioned in the chamber 3. It is released to the atmosphere through the existing degassing passages. Although not shown, the degassing passage may be connected to a separate suction pump for forced degassing.

By the way, as described above, as a method of forming the deaeration passage, a groove is once formed and the groove is covered with a lid member, and then plating is performed on the groove to fix the lid member with a plating layer. With this configuration, the groove and the lid member can be reliably sealed, and the degassing passage can be formed in the chamber in a state of being completely separated from the chamber. Further, since the length of the deaeration hole can be set short, the hole processing becomes easy and clogging is unlikely to occur.

[0020]

As described above, according to the present invention, the heating / cooling of the mold can be performed quickly, so that the molding quality and the productivity can be improved.

[0021]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a mold device according to an embodiment.

FIG. 2 is an enlarged view of a portion A in FIG.

FIG. 3 is a fragmentary perspective view for explaining a deaeration hole and a deaeration groove of the mold device according to the embodiment.

[Explanation of symbols]

 1 Mold main body 2 Cavity surface 2a Degassing hole 2c Degassing groove 3 Chamber 4 Pipe 5 Water supply pump 6 Boiler 9 Vacuum pump

Claims (3)

[Claims] 1. A mold main body having a chamber provided on the back side of a cavity surface, a cooling liquid feeding means for feeding a cooling liquid to the chamber, and a pressure reducing means for reducing the pressure in the chamber. Mold equipment. 2. A deaeration hole opening on the cavity surface communicates with a deaeration groove formed on the back surface of the cavity surface, and the deaeration groove is covered with a lid member and plated from above. The mold apparatus according to claim 1, wherein the cover member is provided and fixed to the mold body. 3. The mold apparatus according to claim 1, further comprising a steam feeding means for feeding heating steam into the chamber.