JPH0866940A - Plastic mold material - Google Patents

Abstract

PURPOSE: To maintain degassing performance for a long time and ensure a strength necessary as a mold. CONSTITUTION: A metal reinforcing block 3 is integrated with a porous metal plate group 21G formed by layering a plurality of porous metal plates 21 having a number of pinholes 21a through which resin can pass. At least a pair of adjacent porous metal plates 21 in the porous metal plate group 21G are layered such that their pinholes 21a are not superposed each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic molding die material.

[0002]

2. Description of the Related Art Generally, a molding die is used for molding a plastic such as an engineering plastic. This molding die is composed of a fixed side die and a movable movable side die, and the movable side die can be opened or closed by moving the movable side die with respect to the fixed side die. . A cavity is formed by clamping the molding die, and the cavity communicates with the tip of the injection nozzle via the sprue. Therefore,
At the time of injection molding, the molten resin injected from the injection nozzle fills the cavity through the sprue.

By the way, when a molded product is molded using such a molding die, the air remaining in the cavity, the water content and the volatile matter contained in the resin (hereinafter referred to as air, etc.) depend on the injection pressure. Although it is partially discharged to the outside through a bonding surface of a mold that is divided into a plurality of parts and assembled, the remainder remains in the cavity without being discharged. When air remaining in the cavity is compressed, it leaves traces on the molded product, or becomes extremely hot (adiabatic compression phenomenon), causing burns (burns) on the molded product. May cause For this reason, there is a need for so-called degassing, in which the air in the cavity is quickly discharged to the outside. Degassing.

However, such a gas venting method cannot be used depending on the mold, and since burrs or the like are generated in the molded product and post-processing is required, metal powder or metal fibers have been used in recent years. It has been attempted to make a mold from a sintered porous sintered body and degas using a small hole (passage) formed between particles of the sintered body. The diameter of the small holes formed in such a sintered body is required to be resin-free in order to ensure the surface accuracy of the molded product, and although it varies depending on the resin material, it is approximately 50 to 150 μm.
It is about m.

[0005]

However, the mold made of the above-mentioned porous sintered body is formed homogeneously in its entirety, and has a lower strength than the mold made of steel material.
Although the gas is smoothly discharged at the beginning of use, there is a problem that the small holes are gradually clogged due to the use, and finally the gas cannot be released. That is, until air or the like passes through the small holes (passages) of the sintered body to the outside, it has to go through a long distance formed intricately intertwined in the three-dimensional direction of the sintered body. In addition, solidification of volatile components such as air, for example, resin additives and decomposition products, clogs the small holes (passages) of the sintered body. The clogged sintered body can partially remove the clogs near the surface by cleaning, but the clogged solidified by entering into the inside cannot be eliminated, and the original degassing performance is restored. I couldn't let you do it.

The present invention has been made in view of the above problems, and it is possible to maintain the degassing performance without clogging for a long period of time and to secure the strength required as a mold. The present invention provides a plastic molding die material that can be manufactured.

[0007]

DISCLOSURE OF THE INVENTION The present invention is directed to a porous member group in which a plurality of porous members having a large number of small holes that allow resin to pass through are laminated, and a metal reinforcing block integrated with the porous member group. Consisting of at least a pair of porous members in a pair of adjacent porous members of the porous member group,
The small hole of one porous member is characterized in that it is positioned so that the center thereof does not coincide with the small hole of the other porous member.

[0008]

During molding, the air in the cavity passes through the porous member group in which a plurality of porous members having a large number of small holes that allow the passage of resin are laminated, and is then discharged to the outside through the metal reinforcing block. . At this time, the molding die material is composed of a thin plate-shaped porous member group laminated so that the small holes of the porous member are narrowed, and a metal reinforcing block that supplements the insufficient strength of these porous member groups. In addition to blocking the passage of resin, the passage distance of air etc. is shortened, clogging is less likely to occur, stable degassing performance can be maintained for a long period of time, and sufficient strength as a mold can be secured. it can.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a molding die material 1 of the present invention. This molding die material 1 is a porous member group formed by laminating a plurality of porous metal plates 21 as porous members 2. Two
G, that is, a group of porous metal plates 21G, and a metal reinforcing block 3 which is integrated with the group of porous metal plates 21G and in which a linear gas vent hole 3a is formed,
A plurality of porous metal plates 21 and a metal reinforcing block 3
Are sequentially stacked, heated and pressed, and sintered.

The porous metal plate 21 is provided with a large number of small holes 21a having a size that allows resin to pass therethrough by corrosion (etching) or electroforming. In particular,
Each porous metal plate 21 is a stainless steel plate having a thickness of 100 μm and small holes 21 a having an average diameter of 100 μm formed in a zigzag shape with a pitch of 0.5 mm. And
The pair of adjacent porous metal plates 21 have their small holes 21.
The small holes 21a are laminated so that the centers of a do not coincide with each other. As a result, the opening area of each small hole 21a is narrowed, and although the passage of air or the like is permitted, the passage of the resin is blocked. In this case, depending on the size of the small holes 21a formed in the porous metal plate 21, it is not necessary to stack all of the adjacent pair of porous metal plates 21 so that the centers of the small holes 21a do not coincide. You may respond | correspond by shifting the center of the small hole 21a and stacking it at least about a pair of porous metal plate 21. Further, the metal reinforcing block 3 is formed by forming straight gas vent holes 3a having a diameter of 1 mm in a steel material at a pitch of 2 mm.

After the plurality of such porous metal plates 21 and the metal reinforcing block 3 are integrated to form the mold material 1, the mold is machined so as to fit the molding apparatus. . At the time of this machining, a chuck made of a magnet can be used by using a steel material for the metal reinforcing block 3.

When a molded product is molded by using a mold made of this molding mold material 1, the air in the cavity is a porous metal plate group 21G, that is, a plurality of laminated porous metal plates 21. Through the small hole 21a in the above, and is discharged to the outside through the straight gas vent hole 3a formed in the metal reinforcing block 3. At this time, in the pair of adjacent porous metal plates 21, since the small holes 21a are laminated without their centers being aligned with each other, the opening area thereof is narrowed to prevent the resin from passing therethrough. The plate group 21G is formed in a thin plate shape so that the distance through which air or the like passes is shortened, and then the plate group 21G is discharged through the straight gas vent holes 3a of the metal reinforcing block 3. As a result, clogging is less likely to occur and stable degassing performance can be maintained for a long period of time. On the other hand, the insufficient strength of the porous metal plate group 21G as a mold is reinforced by the metal reinforcing block 3, and the strength required for the mold as a whole can be secured. Further, even if it is clogged due to long-term use, it is possible to recover almost the original degassing performance by washing.

By the way, in the above-mentioned embodiment, the molding die material 1 using the porous metal plate 21 as the porous member 2 is exemplified, but as shown in FIG. 2, the metal net 22 is used as the porous member 2. A plurality of these wire nets 22 are stacked to form a wire net group 22G that is a porous member group 2G.
The molding die material 1 may be formed by integrating the 2G and the metal reinforcing block 3. In this case, the small holes of the wire netting 22 as the porous member 2, that is, the openings are large enough to allow the resin to pass through, specifically about 0.1 mm.
Even in this case, it is necessary to overlap the meshes 22 so that the sieves do not match.

Further, as shown in FIG. 3, a porous metal plate 21 having a small hole 21a of a size that allows resin to pass therethrough.
Is laminated without overlapping the small holes 21a of the adjacent porous metal plates 21, and further, one or more metal meshes 22 having openings of a size that allows resin to pass are laminated to form a porous metal mesh. The member group 2G may be formed, and the porous member group 2G and the metallic reinforcing block 3 may be integrated to form the mold material 1. Further, as shown in FIG.
Wire mesh 22 having openings of a size that allows resin to pass therethrough
Are laminated without overlapping the meshes of the adjacent wire nets 22, and one or more porous metal plates 21 having small holes 21a of a size that allows resin to pass are laminated to form a porous member. It is also possible to form the group 2G and integrate the porous member group 2G and the metallic reinforcing block 3 to form the mold material 1.

Further, as a modified example of the embodiment shown in FIGS. 3 and 4, instead of the metal net 22 in FIG. 3 and the porous metal plate 21 in FIG. May be adopted (see FIGS. 5 and 6). In this case, the small holes (not shown) formed in the porous sintered body 23 may be of a size that allows resin to pass through, and the particle size and pressure may be adjusted so that the small holes of such size are formed. Need to be adjusted.

In these embodiments, a porous metal plate 21 having a relatively small hole 21a through which resin can pass, a wire mesh 22 with a relatively large opening through which resin can pass, or resin can pass through. By using the porous sintered body 23 having relatively large small holes, there is an advantage that the resin can be prevented from passing through the low cost porous member group 2G.

Although the metal reinforcing block 3 in the above-described embodiment is illustrated by forming a large number of gas vent holes 3a, it may be one gas vent hole 3a. One or a plurality of concave grooves may be formed on the outer peripheral surface to form a gas vent hole, and the gas vent hole 3a may be T-shaped due to the processing relationship.

In addition, since steel is used for the metal reinforcing block 3 in order to perform machining using a magnet chuck, the porous member 2 joined to the metal reinforcing block 3, that is, the porous metal plate 21 or Depending on the compatibility with the material of the wire net 22 or the porous sintered body 23, specifically, non-magnetic metal, for example, stainless steel may be preferable in order to sinter the both, and it is not always the magnetic metal. It is not limited. The mechanical processing in that case may be performed using a mechanical chuck.

Further, in the metal reinforcing block 3, the gas vent hole 3a is formed in advance as an example, but the gas vent hole 3a needs to be machined according to the molding apparatus of the user. It is also possible to ship the die material 1 in which the reinforcing block 3 is in a solid state and leave the processing of the gas vent hole 3a to the user.

[0021]

As described above, according to the present invention, a porous member group in which a plurality of porous members having a large number of small holes that allow resin to pass through are laminated, and a metal member integrated with the porous member group. At least a pair of porous members in a pair of adjacent porous members of the porous member group, which is composed of a reinforcing block, the small hole of one porous member is positioned so that the center does not coincide with the small hole of the other porous member. During molding, air in the cavity passes through the thin plate-shaped porous member group that is laminated so that the small holes of the porous member are narrowed, and the metal reinforcing block that supplements the insufficient strength of this porous member group is formed. As a result of being discharged to the outside after passing through, the resin can be prevented from passing through and the distance through which air etc. can be shortened, clogging is less likely to occur, and stable degassing performance can be maintained for a long period of time. Other, it is possible to secure a sufficient strength as a mold.

[Brief description of drawings]

FIG. 1 is a partial sectional view showing an enlarged first embodiment of a molding die material of the present invention.

FIG. 2 is a partial cross-sectional view showing an enlarged second embodiment of the molding die material of the present invention.

FIG. 3 is a partial cross-sectional view showing an enlarged third embodiment of the molding die material of the present invention.

FIG. 4 is a partial cross-sectional view showing an enlarged fourth embodiment of the molding die material of the present invention.

5 is a partial cross-sectional view showing a modified example of the third embodiment of the molding die material of FIG.

6 is a partial cross-sectional view showing a modified example of the fourth embodiment of the molding die material of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Molding material 2 Porous member 2G Porous member group 21 Porous metal plate 21a Small hole 21G Porous metal plate group 22 Wire mesh 22G Wire mesh group 23 Porous sintered body 3 Metal reinforcement block 3a Gas vent hole

Claims (1)

[Claims] 1. A porous member group in which a plurality of porous members having a large number of small holes that allow resin to pass through are laminated, and a metal reinforcing block integrated with the porous member group. In at least a pair of porous members in a pair of adjacent porous members, the small hole of one porous member,
A plastic molding die material, characterized in that it is positioned so that its center does not coincide with the small hole of the other porous member.