JPH0310028Y2 - - Google Patents

Description

[Detailed description of the invention] <Technical field> This invention relates to the structure of steam holes in a mold for foam molding. In a method of molding a foam molded product by heating the resin particles with steam introduced into the mold cavity and melting and integrating them at the same time as foaming and expansion, the steam is formed through a mold to allow the steam to pass through. It concerns the structure of the pores.

<Prior art> Conventionally, the steam holes of a mold for foam molding were formed with a large number of slit-shaped steam holes penetrating the tip.
A columnar body made of brass with a cylindrical shape with a bottom (Core Benz)
It was common to have a structure in which the mold was formed by driving it into a mounting hole formed through the mold.

However, in the case of the slit-shaped columnar body, steam condensation and cooling water accumulate inside the hollow columnar body, and this accumulated water passes through the slit-shaped steam holes.
There was a problem that it invaded the mold cavity and caused molding defects.

Therefore, instead of the columnar body with slits, it has been proposed to use a columnar body with small holes, which is a solid columnar body with a large number of small holes formed through it to form steam holes. It is disclosed in Publication No. 54-104063, etc. As for the above-mentioned small holes, the more small diameter holes are formed, the greater the effect of preventing water intrusion and the better the circulation of steam. However, in the case of a metal columnar body, small diameter holes are Drilling holes is extremely troublesome and time-consuming, resulting in high processing costs.

Therefore, it was considered to use synthetic resin as the material for the columnar body, which is easier to form small holes and is cheaper in cost than conventional metals such as brass.

However, in the case of the columnar bodies made of synthetic resin, the synthetic resin that is the raw material for the foam molded product tends to adhere to the columnar bodies during foam molding. If the raw material resin adheres to the surface of the columnar body, the supply of steam may not proceed smoothly, making molding impossible, or part of the foam molded product may peel off and remain attached to the columnar body.
Problems such as the surface of the foam molded product becoming dirty occurred.

<Purpose> Therefore, the purpose of this invention is to solve the above-mentioned problems of the conventional technology, and to achieve extremely good results in both preventing water from entering the mold cavity and preventing the adhesion of raw resin. This provides a possible steam vent structure.

<Structure> In order to achieve the above object, in the mounting through-hole formed in the mold, a metal columnar body with a large number of steam holes formed through the through-hole is provided on the inner surface of the mold. The outer surface of the mold is equipped with a synthetic resin columnar body with a large number of small holes for steam holes formed through it, and the metal columnar body and the synthetic resin columnar body are fitted on the outside of the mold. It is characterized in that the sum of the lengths is equal to or longer than the through hole.

<Example> Next, an example of this invention will be described below with reference to the drawings.

FIG. 1 shows the overall structure of the mold, in which molds 10 and 20 are attached to a pair of left and right molds 1 and 2, respectively, and one of the molds 10 is a male mold,
The other mold 20 is formed into a female mold. In addition,
The basic structures of these molds 1, 2 and molds 10, 20 are the same as those for normal foam molding, including steam supply holes, cooling water supply holes,
Alternatively, drain holes and the like are omitted from illustration. Then, over the entire surface of each mold 10, 20, there are mounting through holes 11, 12 for mounting a steam hole member.
are formed, and the columnar bodies of this invention are fitted into the through holes 11 and 12 to form steam holes.

First, as shown in Fig. 3, numeral 3 is a metal columnar body made of metal such as brass, which has a low cylindrical shape with a bottom, and has many narrow slit-shaped steam holes 30 formed through the bottom surface. ing. The slit-shaped steam hole 30 described above is easy to form and process, and the flow rate of steam is large, which is suitable. Reference numeral 31 denotes a non-slip portion, and fine irregularities are formed on the outer periphery of the columnar body 3 by knurling or the like. The anti-slip portion 31 is effective for securely fixing the columnar body 3 when it is driven into the through-holes 11, 21 of the molds 10, 20 and fitted, and as shown in the figure, In addition to being formed with a constant width at the tip, it may be formed over the entire outer periphery of the columnar body 3. The structure of the metal columnar body 3 described above is substantially the same as that of the conventional one, but the overall length is formed shorter than usual.

Next, as shown in FIG. 4, reference numeral 4 denotes a synthetic resin columnar body made of synthetic resin such as polyphenylene sulfide, which has a solid cylindrical shape with the same diameter as the metal columnar body 3. None, a large number of small holes 40 for steam holes are formed through the hole. And the diameter of the small hole 40 is
In order to ensure that water does not pass through, it is preferable to form the diameter of 1.0 mm or less. Note that an anti-slip portion 41 is also formed on the outer periphery of the synthetic resin columnar body 4. Further, the length of this columnar body 4 is considerably longer than that of the metal columnar body 3. As shown in FIG. 2, the sum of the length L1 of the metal columnar body 3 and the length L2 of the synthetic resin columnar body 4 is greater than the length W of the through holes 11 and 21 of the molds 10 and 20. Although the through hole W is formed to be long, it may be formed to have the same length as the through hole W.

The above-mentioned metal columnar body 3 and synthetic resin columnar body 4
are driven into the mounting through-holes 11, 21 of the molds 10, 20 and fitted. As shown in FIG.
Install it so that it is flush with the inner surface of the Furthermore, the synthetic resin columnar body 4 is attached to the outer surface of the molds 10, 20, and the rear end of the columnar body 4 is flush with the outer surface of the molds 10, 20, or a part of the columnar body 4 is attached to the metal mold 10, 20. Type 1
Equipped with 0.20 protruding outward. This is because the synthetic resin columnar body 4 protrudes from the outer surface of the molds 10, 20, so that the water that adheres to and accumulates on the outer surface of the mold 10, 20 is transferred to the synthetic resin columnar body 4.
This is effective in preventing water from flowing in from the ends of the pipe.

In the structure of the steam hole of this invention as explained above, the metal columnar body 3 has the slit-shaped steam hole 30 shown in the figure, as well as the steam hole similar to the conventional columnar body for various steam holes. Alternatively, one having an overall structure can be freely used, and in addition to a cylindrical one, a prismatic one can also be used. If the length of the columnar body 3 is possible to manufacture and handle, the shorter it is, the easier it is to process and the cheaper the cost. Incidentally, as the metal for forming the columnar body 3, brass is suitable because it is easy to process and has good heat conductivity, but other metals can also be used.

Next, as the synthetic resin columnar body 4, in addition to the above-mentioned polyphenylene sulfide, those molded from various synthetic resins such as polycarbonate, polyacetal, and nylon, which are excellent in heat resistance and strength, can be used. . Further, the above-mentioned resin may have a reinforcing material such as glass fiber embedded therein. The small steam holes 40 formed in the synthetic resin columnar body 4 have a diameter of about 1.0 to 0.3 mm, but preferably 0.8 mm or less from the viewpoint of preventing water intrusion. The number of small holes 40 formed is
The flow rate of steam increases when the number is as large as possible, but it is set appropriately in consideration of the strength and workability of the columnar body 4.

<Effects> According to the structure of the steam hole of this invention constructed as described above, a column-shaped column made of synthetic resin is formed with a large number of small holes 40 for steam holes formed through the outer surfaces of the molds 10 and 20. Equipped with inset body 4, water is molded into molds 10 and 2.
This prevents any intrusion into the inside from the outside of the 0.
Since the columnar body 4 is made of synthetic resin, even extremely small holes 40, which were difficult to process with conventional metal columnar bodies, can be easily formed through the holes. In addition to reliably preventing intrusion, machining efficiency is also improved and machining costs are reduced. In particular, since the small holes 40 are easy to process, the number of small holes 40 formed in the columnar body 4 can be increased, or they can be formed closely together, making it possible to further improve the flow of steam. It's also effective.
Moreover, the synthetic resin columnar body 4 is lightweight, and the mold 10,
The weight of the entire column 20 can be reduced, and the manufacturing cost of the columnar body 4 as a whole can be made very low.

If the synthetic resin columnar body 4 is directly exposed to the inner surface of the molds 10, 20, the raw resin or foamed molded product F in the mold cavity will adhere to the columnar body 4. A metal columnar body 3 is inserted into the inner surface of the mold cavity to prevent the raw resin or foamed molded product from adhering to the inside of the mold cavity, maintain good steam circulation, and enable good molding. , the surface of the foamed molded product is made beautiful and the quality of the molded product can be improved.

Furthermore, a metal columnar body 3 and a synthetic resin columnar body 4
Since the sum of the lengths L1+L2 is equal to or longer than the length W of the through holes 11 and 21 of the molds 10 and 20, the It is possible to more reliably prevent water from entering from the end of the synthetic resin columnar body 4.

Therefore, the metal columnar body 3 and the synthetic resin columnar body 4
By effectively utilizing each other's strengths and compensating for their weaknesses, it is possible to realize the most suitable structure for a steam hole.

<Specific example> In order to demonstrate the effect of this invention as described above,
A concrete mold and columnar body were manufactured and foam molding was performed.

The molds 10 and 20 are formed to have a thickness of 12 mm, and therefore the length W of the mounting through holes 11 and 21 is also 12 mm.
It becomes mm. The metal columnar body 3 used had a diameter of 10 mm, a length L1 of 4 mm, and a slit-shaped steam hole. Synthetic resin columnar body 4
The diameter of the hole was 10 mm, the length L2 was 10 mm, and the hole diameter was 0.8 mm with 20 small holes 40 formed therethrough. Therefore, when the metal columnar body 3 and the synthetic resin columnar body 4 are fitted into the molds 10 and 20, the rear end of the synthetic resin columnar body 4 protrudes 2 mm from the back surface of the molds 10 and 20. be equipped with

Next, the external dimensions of the foam molded product to be molded are
The resin particles used as raw materials are molded into 350mm x width 400mm x height 135mm with an average wall thickness of 28mm.
Polystyrene foam beads with an expansion ratio of 12 times were used.

For comparison, the synthetic resin columnar body 4 is the mold 1.
Foaming molding was also carried out under the same conditions for the steam holes of the conventional structure exposed on the inner surface of No. 0 and 20.

As a result, in the conventional case, the resin adhering to the surface of the synthetic resin columnar body 4 had to be peeled off after 10 to 15 times of molding, otherwise molding could not be continued, resulting in poor quality of the foam molded product. It was getting worse, but
In the case of the steam hole structure of this invention, no resin adhered to the surface of the metal columnar body 3, and the quality of the foamed molded product did not deteriorate even when molding was performed continuously.

[Brief explanation of the drawing]

The figure shows an example of this invention.
2 is an enlarged sectional view of section A in the previous figure, FIG. 3 is a perspective view of a metal columnar body, and FIG. 4 is a perspective view of a synthetic resin columnar body. 10, 20... Mold, 11, 21... Mounting through hole, 3... Metal columnar body, 30... Steam hole slit, 4... Synthetic resin columnar body, 40... Small steam hole Hole.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. In a mounting through-hole formed in a mold, a metal columnar body with a large number of steam holes formed through the through-hole is inserted into the inner surface of the mold, and the through-hole The outer surface of the mold is fitted with a columnar body made of synthetic resin with a large number of small holes for steam holes formed through it.
Structure of a steam hole in a mold for foam molding, characterized in that the sum of the lengths of the metal columnar body and the synthetic resin columnar body is equal to or longer than the through hole. . 2. The structure of a steam hole in a mold for foam molding according to claim 1 of the above-mentioned utility model registration claim, in which a large number of slits are formed as steam holes in the metal columnar body. 3. The structure of a steam hole in a mold for foam molding according to claim 1 of the above-mentioned utility model registration claim, wherein a small hole with a diameter of 1.0 mmφ or less is formed as a small hole for a steam hole in a columnar body made of synthetic resin. 4. The structure of the steam hole in the mold for foam molding according to claim 1 of the above-mentioned utility model registration, wherein a non-slip portion is formed on the outer periphery of the metal columnar body and the synthetic resin columnar body.