JPH05148509A - Casting method - Google Patents

Abstract

PURPOSE:To form a formed body from which a homogenous sintered body is made by casting slip in a liquid passing casting mold using a binder which can be solidified on contact with liquid and making the liquid permeate through the binder from outside the casting mold to solidify it. CONSTITUTION:Slip 3 is made of raw material powder, such as metal and ceramics, a binder which can be solidified on contact with liquid (water curable acrylic resin, etc.) and solvent (toluene, etc.) Silicone resin is mixed with cotton 13 bearing water and the mixture is foamed and cured in the prescribed form and heated and dried to remove water, permitting a casting mold 11 having liquid passing property to be produced. The slip 3 is cast in the casting mold 11 and the mold 11 is immersed in water 15 with which a tank 14 is filled. The water 15 is brought into contact with the whole surface of the slip 3 through the mold 11 to cure water curable acrylic resin. By sintering the formed body thus obtained, a homogeneous sintered body is produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting method applied when producing a sintered body of ceramic, metal or the like.

[0002]

2. Description of the Related Art A conventional casting method is, as shown in FIG. 4, casting a slip (3) using a hydraulic binder, for example, on a casting mold (1) made of gypsum, rubber, etc. A method is adopted in which water is sprayed from (2) onto the slip (3) by a water spray nozzle (4) to cure the binder in the slip (3).

[0003]

However, in the above-mentioned conventional method, the contact with water is made only from the casting port (2), and therefore it takes time until the binder is completely cured, and during that time. In the slip (3), the material powder in the slip (3) is separated, a difference in concentration occurs in the slip (3), and when two or more kinds of material powder are mixed and used, the mutual separation due to the difference in specific gravity of the material powder ( (Segregation) occurs, which causes deformation during sintering and also leads to nonuniform product characteristics.

[0004]

As a means for solving the above-mentioned conventional problems, the present invention casts a slip using a binder which is solidified by contact with a liquid in a casting mold having liquid permeability, A casting method for solidifying the binder by allowing a liquid for solidifying the binder to permeate from the outside of the casting mold.

In the present invention, a casting mold having liquid permeability means that continuous bubbles are formed by mixing a water-soluble salt with a mold material such as rubber and eluting the water-soluble salt into water after mold production. Alternatively, it is manufactured by mixing a foaming agent with the above-mentioned mold material and foaming after molding. Furthermore, a liquid-permeable fiber may be mixed with a mold material to produce a mold. In this case, it is desirable to employ a method in which the fibers are impregnated with a volatile liquid, and the liquid is volatilized from the fibers after forming the mold.

The method of forming open cells in the casting mold lowers the strength of the casting mold, but the method of mixing fibers improves the strength of the casting mold by the fibers.

Rubber is desirable as the mold material. This is because rubber is flexible and it is easy to release a molded body that does not shrink during molding without damaging it.

As the binder which is solidified by contacting with the liquid used in the present invention, water-curable urethane resin, water-curable silicone resin, water-curable acrylic resin, alcohol-curable urethane resin, alcohol-curable acrylic resin A synthetic resin that is cured by the liquid itself, a synthetic resin that is cured by an acid or alkali catalyst such as a urea resin, a melamine resin, or a phenol resin, or an epoxy resin that is cured by an amine catalyst is used.

The materials used in the present invention are metals, ceramics, etc., which are dispersed in the slip as powder. The binder is usually added to the raw material powder in an amount of about 0.5 to 5% by weight, and the slip usually has a solid content of about 75 to 95% by weight.

[0010]

In the present invention, the slip is cast in a casting mold, and a liquid for solidifying the binder used in the slip is permeated from the outside of the casting mold.
Thus, the liquid contacts the slip in the casting mold from the entire inner surface of the casting mold and the binder is hardened.

[0011]

EXAMPLE As shown in FIG. 1, SKH51, 70% by volume,
Slip (3) was prepared by using a mixed powder of 30% by volume of Ti N, and mixing 2.5 parts by weight of a water-curable acrylic resin with 100 parts by weight of the mixed powder and 14.0 parts by weight of toluene as a solvent. Then, the slip (3) is cast into the casting mold (11) through the casting port (12). The casting mold (11) mixes 20% by volume of water-containing cotton (13) with silicone resin and foams and hardens it into a predetermined shape. It is then dried by heating to remove water in the cotton (13).

After casting the slip (3), the casting mold (11) is immersed in a water tank (14) filled with water (15). The water (15) permeates from the outside of the casting mold (11), contacts the slip (3) from the entire inner surface (11A) of the casting mold (11), and is water-curable in the slip (3). Cure the acrylic resin.
The relationship between the elapsed time and the solidification capacity in this case is shown in FIG.
Shown in.

The molded body molded in this way is
A homogeneous sintered body is produced by firing at 0 ° C. for 1 hour, and the molded body (3A) is divided into compartments from the top as shown in FIG. 3, and the density of each compartment is measured. To do. The results are shown in Table 1. For comparison, the relationship between the elapsed time and the solidification capacity in the case of molding by the conventional method shown in FIG. 4 using a silicone rubber casting mold having no open cells and no cotton mixed is shown in FIG. 2 graph B. The density of each section of the molded product is shown in Table 1.

[0014]

[Table 1]

According to FIG. 2, according to the present invention, the solidification rate of the slurry is remarkably higher than that of the conventional method, and according to Table 1, the density of the molded body is uniform in the upper and lower sides according to the present invention. It can be seen that the solidification rate is slow and therefore separation occurs due to the difference in specific gravity of the mixed powder, and the density fluctuates up and down.

[0016]

Therefore, in the present invention, since the liquid comes into contact with the slip from the entire inner surface of the casting die, the binder in the slip is rapidly hardened, and the raw material powder is not separated or segregated, so that a homogeneous sintered body is obtained. can get.

[0017]

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a graph showing the relationship between elapsed time and solidification capacity in slurry casting.

FIG. 3 is an explanatory view of a molded body

FIG. 4 is a sectional view of a conventional example.

[Explanation of symbols]

 11 Casting type 13 Cotton 14 Water tank 15 Water 3 Slip

[Procedure amendment]

[Submission date] July 10, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Delete

Claims (2)

[Claims] 1. A binder which is solidified by contacting with a liquid in a liquid-permeable casting mold is cast, and a liquid for solidifying the binder is permeated from the outside of the casting mold to allow the binder to penetrate. Casting method characterized by solidifying the 2. The casting method according to claim 1, wherein the casting mold is made of liquid-permeable rubber.