JP3084922B2 - Core for manufacturing hollow metal article and method for manufacturing hollow metal article using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core for manufacturing a hollow metal article used for manufacturing a hollow metal article and a method for manufacturing a hollow metal article using the same.

[0002]

2. Description of the Related Art As one conventional example of manufacturing a hollow metal article, for example, a technique disclosed in Japanese Patent Application Laid-Open No. 3-87302 has been proposed.

[0003] This technology uses acrylic, polyacetal,
A core is formed from a resin such as polyphenylene oxide, ABS, polyethylene, or the like, and the core is embedded in a green body formed by a mixture of a metal powder and a binder made of polyethylene, acrylic, or the like, and the green body is heated. By volatilizing the binder and the core in the green body, a hollow portion similar to the core shape is formed in the brown body changed from the green body, and further, the brown body is fired to form a hollow metal article. It is to be formed.

[0004]

According to the above-mentioned prior art, hollow metal articles can be manufactured, but the following problems remain to be improved.

That is, a core made of an acrylic resin, a polyacetal resin, or the like in the above-mentioned conventional technique becomes fluid when the core is volatilized by heating, so that a thin metal article is formed. In such a case, the green body attached to the outside may be deformed.

In addition, since the glass transition point of the core of the above composition is usually 150 ° C. or higher, it is difficult to form at room temperature, so that free molding such as clay cannot be performed. Is restricted.

[0007]

SUMMARY OF THE INVENTION The present invention provides a core for manufacturing a hollow metal article and a method for manufacturing a hollow metal article using the same, which can effectively solve the above-mentioned conventional problems. The hollow metal article manufacturing core according to claim 1,
65% to 92% by weight of the water-insoluble cellulose resin,
The water-soluble cellulose resin has a composition of 0.5 to 8% by weight, a fat or oil of 0.3 to 5% by weight, and a balance of water and unavoidable impurities. Claim 2
The method for producing a hollow metal article according to the present invention is characterized in that the water-insoluble cellulose resin is 65% to 92% by weight, the water-soluble cellulose resin is 0.5% to 8% by weight, and the fat or oil is 0.3% by weight or less.
A core having a desired shape is formed by a hollow metal article manufacturing core having a composition consisting of 5% by weight, the balance being water and unavoidable impurities, and a metal powder is adhered to an outer peripheral surface of the core to form a metal layer. In this manner, an intermediate of the metal article is formed, and then the intermediate is subjected to a heat treatment to burn and vaporize the core, and then firing the metal layer. In the method for manufacturing a hollow metal article according to a third aspect, in the method for manufacturing a hollow metal article according to the second aspect, the core is dried and solidified prior to forming a metal layer on the surface of the core. It is characterized by the following. Claim 4
The method for producing a hollow metal article according to the above is the method for producing a hollow metal article according to claim 2 or 3, wherein the metal layer is formed of a metal plastic composition obtained by mixing a metal powder and an organic binder. It is characterized by having been formed. A method for manufacturing a hollow metal article according to claim 5 is the method for manufacturing a hollow metal article according to any one of claims 2 to 4, wherein the metal layer formed on the surface of the core includes:
It is characterized in that it is formed in a multi-layered form by metals having different compositions after firing. According to a sixth aspect of the present invention, in the method of manufacturing a hollow metal article according to any one of the second to fifth aspects, the metal layer is a noble metal layer.

[0008]

According to the first aspect of the present invention, the core for manufacturing hollow metal articles has the above-mentioned component ratio, has sufficient plasticity at room temperature before drying, enables free molding, and has a solid shape upon heating. Burns and vaporizes in phase. In addition, after drying and solidification, the core has a sufficient hardness, and thus, it is possible to manufacture a core without deformation by forming and then drying in a state having flexibility.

According to the method for manufacturing a hollow metal article according to the second aspect, the metal obtained by forming the core by utilizing the good plasticity of the core for manufacturing a hollow metal article having the above component ratio. Inside the article, it becomes possible to form a hollow part of a complicated shape, and by using the property of burning and vaporizing in the solid state of the core, the core component can be smoothly removed. Thus, it is possible to form a hollow portion in the metal layer while preventing deformation of the metal layer formed on the core surface.

According to the method for manufacturing a hollow metal article according to the third aspect, in addition to the second aspect, the metal layer can be easily formed by ensuring the support when forming the metal layer, and the metal layer can be deformed. To prevent

According to the method for manufacturing a hollow metal article according to the fourth aspect, the metal layer is formed of a metal plastic composition, thereby facilitating the formation of the metal layer.

According to the method of manufacturing a hollow metal article according to the fifth aspect, for example, by adjusting the inner and outer surfaces of the metal layer to have different specific gravities, the weight and the like of the obtained metal article can be adjusted.

According to the method for manufacturing a hollow metal article according to the sixth aspect, it is possible to form a precious metal article while reducing the amount of expensive precious metal used.

Here, specific examples of the respective components and the reasons for limiting to the above-mentioned mixing examples will be described.

(A) Water-insoluble cellulose resin This water-insoluble cellulose resin is methyl cellulose,
Ethyl cellulose, carboxymethyl cellulose, pulp, or the like is used and forms a solid component of the core. If the amount is less than 65% by weight, the composition of the present invention becomes too soft and molding becomes difficult. If it exceeds 92% by weight, the elongation becomes small,
Since cracks and the like are likely to enter during molding and molding becomes difficult, the compounding amount of the water-insoluble cellulose resin is set to 6
5 wt% to 92 wt%.

(B) Water-soluble cellulose resin This water-soluble cellulose resin includes water-soluble methyl cellulose, water-soluble ethyl cellulose, carboxymethyl cellulose ammonium salt, carboxymethyl cellulose sodium salt and the like. It has a function of a binder for connecting a functional cellulosic resin in an adhesive state. When the amount is less than 0.5% by weight, the desired strength cannot be obtained even when the molded article of the composition of the present invention is dried and solidified. Since the composition becomes jelly-like or agar-like and becomes difficult to mold, the blending amount of the water-soluble cellulose resin is set to 0.5% by weight to 8% by weight. (C) Fats and oils These fats and oils include, for example, so-called fats and oils such as olive oil and corn oil, polyhydric alcohols such as ethylene glycol and glycerin, higher alcohols such as polyethylene glycol, di-N-butyl phthalate, and diethylhexyl phthalate. And a higher organic acid ester such as di-N-octyl phthalate, an organic compound such as sorbitan monooleate, etc., and the resulting core for manufacturing hollow metal articles is attached to a hand or a molding jig at the time of molding or the like. It is for suppressing that. And this compounding amount is 0.3% by weight
If it is less than 5%, the effect of preventing adhesion of the composition at the time of molding is small, and if it exceeds 5% by weight, the composition becomes oily and difficult to mold. It was 3% by weight to 5% by weight. When a small amount of a surfactant is added during the production of the core for producing a hollow metal article, kneading and mixing of the components can be facilitated.

[0017]

EXAMPLES The plastic composition for producing a core according to the first aspect will be described below with reference to examples. Carboxymethyl cellulose, carboxymethyl cellulose ammonium salt, di-N-butyl phthalate, and kneaded with water,
Cores for manufacturing hollow metal articles having the mixing ratios shown in Examples 1 to 4 in Table 1 were obtained.

[0018]

[Table 1]

As a comparative example, the above components were
Compositions having the compounding ratios shown in Comparative Examples 1 to 6 in Table 2, which were out of the upper limit and the lower limit, were produced.

[0020]

[Table 2]

For these Examples 1 to 4 and Comparative Examples 1 to 6, elongation at room temperature, adhesion to other substances, hardness after drying, and solid phase combustion A test was conducted for the characteristics, and the results were shown in Tables 3 and 4, respectively.
It was shown to.

The test conditions are as follows. Elongation: Each Example and each Comparative Example were formed into a predetermined shape, and a tensile force was applied thereto at room temperature, and the elongation at the time when the fracture occurred was measured. Adhesion to other substances; check the state of adhesion to the hands when kneading each Example and each Comparative Example by hand. "O" indicates no adhesion and slight adhesion is observed. Is indicated by “△”, and the case where the amount is large is indicated by “×”. Hardness after drying; each Example and each Comparative Example
After drying for 4 hours and cooling at room temperature, the diameter was 5 m.
m was pressed against each of the test specimens with a static load of 500 g, and at that time, the size of the diameter D of the depression formed in each test specimen was measured. Solid phase combustion characteristics: Each example and each comparative example were burned at 600 ° C., and the occurrence of fluidity at that time was examined.

[0023]

[Table 3]

[0024]

[Table 4]

As is evident from the results, when the components and the compounding ratios of the respective examples of the present invention are within the ranges, the resin has elongation at room temperature, has low adhesion to other substances, and is easy to handle. A core for manufacturing a hollow metal article having high moldability can be obtained. Further, by vaporizing without passing through a liquid phase during combustion, a hollow metal article manufacturing core having no fluidity and not affecting the shape of the metal layer formed on the surface is obtained, After being dried and solidified, a core for producing a hollow metal article having sufficient hardness and not being deformed by its weight when forming a metal layer on the surface is obtained.

Next, a method of manufacturing the hollow metal article according to claim 2 will be described. First, after a core having a predetermined shape is formed by each hollow metal article manufacturing core (Examples 1 to 4) generated in the invention of claim 1, Au powder having an average particle diameter of 20 μm is formed on the surface thereof. A noble metal plastic plastic which is mixed with an organic binder to form a clay is formed to form a metal layer.
The core was burned and vaporized by heating at 1 ° C. for 1 hour, and further fired in air at 1020 ° C. for 2 hours or more to obtain a hollow metal article.

Here, when the outer shape of the metal layer was compared between the time of compacting and the time after the core was removed by burning, almost no change was observed. This is considered to be because the core was burned and vaporized in the solid phase during the combustion, and the component escaped from between the metal particles of the metal layer to the outside.

When each hollow metal article obtained as described above was cut and examined for its inner shape, it had an inner shape similar to the outer shape of the core, although there was a slight dimensional difference. It was confirmed that a space was formed.
This dimensional difference is due to shrinkage that usually occurs during firing of the metal layer.

Therefore, according to the method for manufacturing a hollow metal article according to claim 2, when forming the hollow metal article,
The internal shape can be controlled with high accuracy, and the change in the external shape can be suppressed.

The embodiment according to the second aspect of the present invention is merely an example, and can be variously changed depending on the shape of the target hollow metal article.

For example, when manufacturing a hollow metal article having a protruding part, for example, when forming a figure of a person whose hand is pushed up, as shown in FIG. The arm 3 must be formed in a protruding shape.

Then, a metal is deposited on the surface of the core 1 to form a metal layer 4 as shown in FIG. 2. In this case, the metal has a large specific gravity. It is assumed that the weight of the metal layer 4a formed on the protruding arm 3 of the child 1 causes the arm 3 to be deformed downward.

In this case, after the core 1 as shown in FIG. 1 is formed, it is dried and solidified under the conditions described in claim 1, and thereafter, the metal layer 4 is formed on the surface of the core 1. I just need.

When the metal layer 4 is formed on the surface of the core 1 by such a method, since the dried and solidified core 1 has sufficient hardness as described in claim 1, In addition, the metal layer 4 sufficiently bears the weight of the metal layer 4 and its deformation is prevented, and a shape having a long protruding portion as shown in FIG.

Also in this case, the core 1 is vaporized and removed under the solid-phase combustion, and a hollow having the same shape as the core 1 shown in FIG. Part is formed, and by further firing this metal layer 4,
A hollow metal article having substantially the same outer shape as the outer shape of the metal layer 4 shown in FIG. 2 is obtained.

When a metal layer is formed on the surface of the core, a metal powder is mixed with an organic binder to form a clay-like metal-plastic composition. Although the example in which the metal powder is adhered to the surface is shown, the metal powder may be directly adhered instead.

Further, the metal layer may be formed in a multilayer shape with metals having different structures after firing. For example, the inner layer is formed of an inexpensive metal, and the outer layer is formed of an expensive metal, so that the amount of noble metal or the like can be reduced.

On the other hand, as a metal for forming the metal layer, a noble metal such as Au, Ag, Pt, Pd or an alloy thereof, or Al, Ni, Co, Fe, Cu, Ti,
One or a mixture of two or more powders selected from Zn, Sn, Zr, V, Pb, Cr and the like and alloys thereof are used.

[0039]

As described above, according to the present invention,
Before drying, sufficient plasticity can be imparted at room temperature to perform free shaping, and at the time of removal by combustion, the solid phase is burned and vaporized to deform the metal layer formed on the surface of the core. To produce a core that can provide sufficient hardness after drying and solidification, reliably support the weight of the metal layer formed on the surface, and prevent its deformation. Can be.

Thus, even in the case of a metal article having a complicated shape, a hollow portion can be reliably and accurately formed inside the metal article.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing an example of a core formed by a core for manufacturing a hollow metal article according to the present invention.

FIG. 2 is an external perspective view showing a state in which a metal layer is formed on the surface of the core shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Core 2 Body 3 Arm 4 Metal layer

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B22F 7/00

Claims (6)

(57) [Claims] (1) 65% by weight of a water-insoluble cellulose resin
~ 92% by weight, 0.5% by weight of water-soluble cellulose resin
A core for manufacturing a hollow metal article, characterized in that the core has a composition of about 8% by weight, 0.3% by weight to 5% by weight of fats and oils, and the balance consisting of water and inevitable impurities. 2. The water-insoluble cellulose resin is 65% by weight.
~ 92% by weight, 0.5% by weight of water-soluble cellulose resin
A core having a desired shape is formed by a core for manufacturing a hollow metal article having a composition of about 8% by weight, a fat and oil of 0.3% by weight to 5% by weight, and the remainder consisting of water and unavoidable impurities. A metal powder is adhered to the surface to form a metal layer, thereby forming an intermediate of the metal article, and then heat-treating the intermediate to burn and vaporize the core, A method for producing a hollow metal article, comprising firing a layer. 3. The method for manufacturing a hollow metal article according to claim 2, wherein the core is dried and solidified before forming a metal layer on the surface of the core. Manufacturing method. 4. The method of manufacturing a hollow metal article according to claim 2, wherein the metal layer is formed of a metal plastic composition obtained by mixing a metal powder and an organic binder. A method for manufacturing a hollow metal article. 5. The method for manufacturing a hollow metal article according to claim 2, wherein the metal layer formed on the surface of the core is formed into a multilayer shape by using a metal having a different composition after firing. A method for producing a hollow metal article, comprising: forming a hollow metal article; 6. The method for manufacturing a hollow metal article according to claim 2, wherein said metal layer is a noble metal layer.