JPH05287313A - Isostatic powder molding die and powder molding method thereof - Google Patents

Abstract

PURPOSE:To provide a large-sized isostatic powder molding die for producing are intricate shape parts from a powdery ceramic or a powdery metal, and a powder molding method using the die. CONSTITUTION:A powdery material 8 is filled in a metallic mold consisting of a die 2 and the upper punch 1 and lower punch 3 to be inserted into the die, and the powder-filled part is evacuated. The isostatic powder molding die is directly inserted into a CIP device to compact the powder. Consequently, a powder product is easily produced, and a large-sized member of intricate shape is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrostatic powder molding die used for the production of large-sized complex shaped parts using ceramic powder or metal powder as a raw material, and a powder molding method using the same.

[0002]

2. Description of the Related Art Conventionally, a technique for obtaining a final product by subjecting powder of metal, ceramics or the like as a raw material to die press molding and sintering has been often used as a method for producing a powder product.
However, when performing die press molding on a product having a large cross-sectional shape, a large press machine is required to obtain an appropriate molding pressure. Usually, when molding large products,
The cold isostatic pressing method (CIP method) is used, but C
Since the IP method uses rubber as a mold, the dimensional accuracy after molding is inferior to that of mold molding.

Therefore, in order to manufacture a large-sized member with high dimensional accuracy, a die integrated with a powder material is used as a CIP.
It is possible if it is inserted into the inside and molded. However, in this molding method, it is necessary to wrap and seal the mold with rubber or the like that can prevent the liquid as the pressure medium from flowing into the mold and can sufficiently transmit the pressure.

Furthermore, it is necessary to reduce the pressure inside the mold which is wrapped with rubber or the like so that the pressure is sufficiently transmitted, and with a simple rubber mold, there is a possibility that the rubber mold may be caught during molding. .. As described above, in order to actually perform CIP using a normal mold, many problems remain in the method of encapsulating the mold in a rubber mold or the like under reduced pressure.

[0005]

SUMMARY OF THE INVENTION The present invention aims to develop a powder molding die and a molding technique capable of easily molding a powder product under the above-mentioned conditions and for obtaining a large-sized complex shaped member. To aim.

[0006]

According to the method for producing a powder compact of ceramics, metal powder or the like according to the present invention, a die for molding the powder into a predetermined shape is depressurized inside the die filled with the powder. A possible powder molding die is characterized in that the die is directly inserted into a CIP device and pressure-molded without being enclosed in a rubber die or the like.

[0007]

The powder molding die according to the present invention and the powder molding method by isostatic pressing (CIP) will be described in detail below. FIG. 1 shows an example of a powder molding die for isostatic pressing according to the present invention. For simplicity, the mold has a cylindrical shape,
One-sided pressing (only the upper punch is movable). This powder molding die is composed of an upper punch 1, a die 2, a lower punch 3, an upper punch fixing jig 4, a tightening bolt 5, an O-ring 6 and a vacuum exhaust valve 7. Further, 8 is a powder material.

More specifically, the actual powder filling and molding process will be described below. First, after the O-ring 6 is attached to the lower punch 3, the lower punch 3 is fixed to the die 2 with the tightening bolt 5, and the powder material 8 is filled. At this time, the vacuum exhaust valve 7 is opened. Then the upper punch 1
Is inserted into the upper punch fixing jig 4 to which the O-ring 6 is attached. Then, this is fixed to the die 2 with the tightening bolt 5, and the powder filling and the die assembly are completed.

Thereafter, the powder filling portion is evacuated from the vacuum exhaust valve 7 by a vacuum pump to reach a predetermined degree of vacuum, and then the vacuum exhaust valve 7 is closed to bring the powder filling portion into a depressurized state.

The predetermined isostatic pressing is carried out under such a reduced pressure of the powder filling. As a result, it becomes possible to manufacture a powder compact in conformity with the shapes of the upper punch 1, the lower punch 3 and the die 2.

[0011]

EXAMPLES Molding was performed in the shape shown in FIG. The dimensions are d ₁ = 500 mm, d ₂ = 200 mm, d ₃ = 300 mm,
h ₁ = 100 mm and h ₂ = 20 mm. FIG. 3 shows a mold for molding this powder compact. Alumina powder (average particle size after granulation: 100 μm) was used as the powder material.

In the actual assembly of the mold, the lower punch 3 is attached to the die 2 via the O-ring 6 with the tightening bolt 5 according to FIG. After inserting the alumina powder into the mold, the upper punch fixing jig 4 with the upper punch inserted through the O-ring 6 was fixed with the tightening bolt 5.

Next, the pressure was reduced from the vacuum exhaust valve 7 to 0.1 Pa by a rotary pump and the valve was closed. Thereafter, isostatic pressing was carried out according to a conventional method to obtain a powder compact as shown in FIG.

[0014]

Industrial Applicability According to the present invention, a powder molding die capable of depressurizing the inside of the die filled with the powder of the die for molding the powder into a predetermined shape is used. It is possible to obtain a powder compact close to the intended product shape by directly inserting it into the CIP device and press-molding it without enclosing it in the.

[Brief description of drawings]

FIG. 1 is an explanatory view of one specific example of a powder molding die for isostatic pressing according to the present invention.

FIG. 2 is a schematic view of the shape of an alumina molded body that is an example of the present invention.

3 is an explanatory view of a mold of the molded body of FIG.

[Explanation of symbols]

 1 Upper punch 2 Die 3 Lower punch 4 Upper punch fixing jig 5 Tightening bolt 6 O-ring 7 Vacuum exhaust valve 8 Powder material

Claims (2)

[Claims] 1. A hydrostatic molding powder comprising a die having an evacuation valve, an upper punch and a lower punch which are inscribed in the die and are attached via an O-ring. Molding die. 2. A die having an evacuation valve, an inward die inside the die, and an upper punch and a lower punch attached via an O-ring and filled with a powder material. A powder molding method, characterized in that a mold in which the powder filling portion is in a depressurized state is directly inserted into a CIP device to perform pressure molding.