JPH07108477B2 - Rubber press molding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention performs a rubber press molding method by hydrostatic pressing, more specifically, a near net molding close to a desired final shape using the same rubber case having a simple shape. The present invention relates to a rubber press molding method.

[Conventional technology]

The rubber pressing method is widely used as a molding means for obtaining a powder compact having an isotropic structure. This molding method is to fill the rubber case with fine powder powder and then apply uniform hydrostatic pressure from all directions through the liquid medium to mold.
The obtained molded product is characterized by being imparted with a high degree of isotropy and a dense structure. However, the shape to be molded is governed by the shape of the rubber case used, so if you want to change the size or obtain a molded body with a different shape, make a rubber case for near-net molding each time. Alternatively, a method such as cutting from a large-sized molding block body is adopted.

Among these, when a near crucible or a cylindrical molded body is to be obtained by near-net molding, for example, a rubber container having a hollow concave portion 1 in the central portion as shown in FIGS. 4 (a) and 4 (a). A thick rubber case composed of 2 and a rubber lid 3 is used. However, when such a thick-walled rubber case is used, the molded body is subjected to large stress and interfacial frictional force due to the springback action of the rubber case that occurs during the step-down step after molding, resulting in molding defects such as cracks and breakage. Occurs frequently.

[Problems to be Solved by the Invention]

INDUSTRIAL APPLICABILITY The present invention efficiently performs near-net molding by using the same rubber case having a simple shape such as a square shape or a cylindrical shape without using a rubber case having a complicated shape along the final shape such as the conventional near-net molding. The purpose is to provide a rubber press molding method that can be performed.

The rubber press molding method according to the present invention is particularly useful for a molding step in the process of manufacturing a carbonaceous material having an isotropic dense structure.

[Means for Solving the Problems]

The rubber press molding method according to the present invention for achieving the above object is composed of an organic material that is plastically deformable and has a small springback amount in rubber press molding in which a rubber case is filled with molding powder and subjected to hydrostatic pressure. A structural feature is that the molded product having the arbitrary shape is interposed as a lining layer or a core in the rubber case so as to follow a molded body that is close to the final shape of the rubber press molded body.

In the present invention, as the organic material capable of being plastically deformed and having a small springback amount interposed in the rubber case as a molded product of an arbitrary shape, for example, rubber such as natural rubber or synthetic rubber, or foam material such as Styrofoam is used. be able to. Of these, Styrofoam is most suitable for the purpose of the present invention in that it is easily compressed and deformed, has a small springback property, and can be blow-molded.

In the present invention, interposing the above-mentioned molded product of an arbitrary shape in the rubber case means that the molded product is placed in the rubber case so that the rubber press molded product is near-net molded along a structure close to the final shape. It means to arrange, and specifically refers to a mode in which it is formed as an inner lining layer on the inner surface of the rubber case or installed as a core at an appropriate position in the rubber case.

FIG. 1 is a plane cross-sectional view illustrating a molding mode in which an organic molded product 5 which is plastically deformable and has a small springback amount is interposed as an inner lining layer having a constant thickness on the inner wall of the rubber case 4. The powder 6 is hydrostatically pressurized while being filled in a space smaller than the rubber case 4.
Therefore, it is effective in obtaining a compact having a smaller size than the rubber case 4.

FIG. 2 is a side sectional view showing a molding mode which is effective for obtaining a molded product such as a crucible or a cylinder. A cylindrical container formed of expanded polystyrene 7 is filled with powder or fluid 8 which does not harden upon pressurization. After forming a molded product and setting it as the core in the center of the bottom of the cylindrical rubber case 4, the molding powder 6 is filled. Molding is performed in this state, and after molding, a molded body 9 released from the rubber case as shown in FIG.
The bottom of the styrofoam 7 is broken and the powder or fluid 8 in the container is discharged.

As the powder which is packed in the container of the styrofoam 7 in this molding mode and does not harden under pressure, coke particles having a uniform particle size, sea sand and the like can be mentioned. Water is used as the fluid, and gel (superabsorbent polymer) is used. In the case of water, put it in a rubber bag, and in the case of gel, put it in a container such as a rubber bag, Styrofoam or vinyl bag. .

When the above-mentioned rubber press molding method is applied to the step of molding an isotropic carbon material, the interposed organic molded product is volatilized and removed in the subsequent firing step, so that it is not necessary to peel it from the molded body.

[Action]

In the rubber press molding method of the present invention, a plastically deformable molded product of an organic material having a small springback amount in the laver case is interposed as an inner lining layer or core along the final molded body, Since the hydrostatic pressure is applied in this state, the organic molded product deforms following the applied pressure. Deformation of the organic molded product in this process progresses extremely smoothly, especially when the molded product is filled with powder or fluid that does not cure when pressurized in a styrofoam container or a styrofoam container, and occurs when the pressure is reduced. Since the springback phenomenon is greatly suppressed, unnecessary stress that causes cracks, breakage, etc. is not applied to the rubber press molded body. Further, since the portion where the organic molded product is interposed serves as a protective layer, it is possible to prevent corner breakage at the releasing step.

By such an action, it becomes possible to always perform near-net molding close to a desired final shape with high molding efficiency.

〔Example〕

 Hereinafter, the present invention will be described based on examples.

Example 1 Square tube type rubber case (thickness 150 mm, width 400 mm, height 500 m
A 15 mm-thick molding layer formed of expanded polystyrene was lined on the entire inner wall of m) (the same mode as in FIG. 1).

This rubber case was filled with a carbonaceous molding powder obtained by finely grinding a kneaded product of 70% by weight of petroleum coke fine powder and 30% by weight of tar pitch to an average particle size of 50 μm, and using a hydrostatic pressing (CIP) device according to a conventional method. It was molded at a pressure of 1000 kg / cm ² .

The size of the obtained isotropic carbonaceous molded body is 110 mm in thickness,
It is smaller than the case of using a rubber case with a width of 330 mm and a height of 420 mm that does not form an inner lining layer (135 mm in thickness, 360 mm in width, 450 mm in height), and the molded structure has defective parts such as cracks, breakage, and corner chipping. Was not recognized.

Example 2 Outer diameter 300 mm, inner diameter 270 mm and height 10 formed by Styrofoam
A 00 mm cylindrical container was filled with coke particles having a particle size of 0.3 to 1.0 mm to prepare a molded product.

The molded product was set as a core in the center of a cylindrical rubber case having a diameter of 500 mm and a height of 1000 mm, and the same carbonaceous molding powder as in Example 1 was filled in the space. In this state, it was transferred to a hydrostatic press machine and subjected to a molding treatment at a pressure of 1000 Kg / cm ² .

After releasing the mold, the bottom portion of the Styrofoam container was broken and the coke grains were discharged.

The obtained isotropic carbonaceous compact has an outer diameter of 420 mm and an inner diameter of 260 m.
It was a cylinder with a height of 900 mm and a dense structure with no cracks or damage.

Then, when a firing treatment was performed with the styrofoam lining layer interposed in the center hole, the organic components that compose the lining layer were beautifully volatilized and removed, and a cylindrical carbonaceous material close to the desired final shape could be obtained. It was

〔The invention's effect〕

As described above, according to the rubber press molding method of the present invention,
It is possible to smoothly and efficiently obtain a molded body having a complicated final shape by using the same simple rubber case.

Therefore, it is possible to prepare rubber cases of various shapes and to form a desired molded body without causing a large processing loss. Therefore, particularly in the process of manufacturing an isotropic carbon crucible, a cylinder or the like. It is useful as a near net molding process.

[Brief description of drawings]

1 is a plan sectional view of a rubber case exemplifying an embodiment of the present invention, FIG. 2 is a side sectional view of a rubber case exemplifying another embodiment, and FIG. 3 is obtained with the rubber case of FIG. It is a processing explanatory view of the formed body. FIG. 4 shows a conventional rubber case. (A) is a side sectional view, (A) is (A).
FIG. 9 is a plan sectional view taken along line AA ′ in FIG. DESCRIPTION OF SYMBOLS 1 ... Recessed position, 2 ... Rubber container 3 ... Rubber lid, 4 ... Rubber case 5 ... Plastically deformable organic molded product 6 ... Molded powder, 7 ... Styrofoam 8 ... Powder or fluid, 9 ... Molded product

Claims (3)

[Claims] 1. In a rubber press molding in which a rubber case is filled with molding powder and subjected to hydrostatic pressure, a molded product of an arbitrary shape made of an organic material which is plastically deformable and has a small springback amount is formed by a rubber press. A rubber press molding method characterized by interposing a lining layer or a core in a rubber case along a shape close to the final shape of the molded body. 2. The rubber press molding method according to claim 1, wherein the organic material capable of being plastically deformed and having a small springback amount is expanded polystyrene. 3. A styrofoam container is filled with powder or fluid that does not cure when pressed to form a molded product, which is molded as a core set in a rubber case. The rubber press molding method according to claim 1, wherein the rubber press molding is performed.