JPH05132351A - Production of porcelain - Google Patents

Abstract

PURPOSE:To uniformize the pressure distribution, facilitate the demolding, provide a higher efficiency of a forming process and improve the yield by reciprocating a metallic mold in the pressurizing direction in forming powder with the metallic mold for pressurizing the powder in the uniaxial direction. CONSTITUTION:Powder (e.g. alumina having 3-40mum grain size distribution) 2 is charged from the upper part of a metallic mold 3 and then compacted with punching rods 1 of a uniaxial press under about 1.5t/cm<2> pressure. In the process, the metallic mold 3 is reciprocated in the direction parallel to the pressurization at about 5mm stroke from the beginning of the pressurization at a frequency of 0.2-10 times per see. The upper punching rod 1 is then removed and the resultant compact is subsequently pushed up and demolded with the lower punching rod 1 while pressing the metallic mold 3 with a demolding jig (not shown in the figure).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing porcelain.

[0002]

2. Description of the Related Art Generally, in the process of press-molding powder in the manufacture of porcelain, it is necessary to sufficiently consider the powder in addition to uniformly pressing the powder.

As a method for facilitating the mold release from the mold, a method of adding a release agent such as stearic acid to the powder,
There are methods such as applying wax and fluorine to the mold, and methods such as tapering angles to improve the mold design.

Although these methods are certainly effective and have been put to practical use, they require process steps such as mold release agent application and addition processes, and special techniques for mold processing. It had the problem of becoming complicated.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a method for manufacturing a porcelain in which pressure can be uniformly applied to the powder without causing excessive complexity in the process design and the mold can be easily removed from the mold. To provide.

[0006]

In order to achieve the above object, the present invention provides a porcelain having a step of molding a powder obtained by pulverizing and sizing a raw material, and a step of heat-treating a molded body obtained thereby. In the manufacturing method, in the molding step,
When molding powder using a mold that presses in a uniaxial direction,
The feature is that the mold is adapted to reciprocate in parallel to the pressing direction.

[0007]

In the present invention, when the powder of the raw material is pressed in the mold, the powder is compressed and pressed against the inner wall of the mold, so that the adhesive force between the powder and the inner wall of the mold is increased. However, by reciprocating the mold in the pressurizing direction, the adhesion of the powder to the inner wall of the mold is reduced, and as a result, a uniform pressure distribution is obtained. Can be easy.

The present invention can be achieved by modifying a conventional die pressing apparatus to improve the die so that it can be reciprocally moved in the pressing direction.

[0009]

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

FIG. 1 shows a die pressing apparatus according to an embodiment of the present invention.

That is, the powder 2 is put in the space formed by the punch rod 1 and the die 3, and the punch rod 1 pressurizes the powder 2. Further, the mold 3 is shown in FIG.
As indicated by the arrow 4, a minute reciprocating movement is possible in parallel with the direction of pressing by the punch rod 1.

When the powder 2 is pressed by the punch rod 1, the powder 2 is compressed and pressed against the inner wall of the mold, so that lateral pressure is generated. However, in the embodiment of the present invention, since the mold 3 can be reciprocated slightly in the pressing direction, the mold 3
Since the interface between the inner wall surface of the mold and the powder 2 is constantly moving, even if the powder 2 is pressed against the inner wall of the mold, the inner wall surface of the mold 3 and the powder 2 are in close contact with each other. Is reduced.

When the mold 3 is fixed, when the powder is pressed against the inner wall of the mold by the lateral pressure generated by the pressurization of the punch bar 1, the inner wall surface of the mold 3 and the powder 2 adhere to each other. As a result, the powder is constrained to move in parallel to the pressing direction, resulting in non-uniformity in the powder pressure distribution. In addition, finally, the green compact is firmly adhered to the die 3, which causes difficulty in die cutting. Further, since the pressure is non-uniform, the density inside the green compact becomes non-uniform, which easily causes the laminating phenomenon and causes the porcelain after the heat treatment to be distorted.

In the present embodiment, as shown by the arrow 4 in FIG. 1, by reciprocating the die in the direction of the mark 4, the adhesion of the powder to the inner wall of the die is reduced, and as a result, it is uniform. A wide pressure distribution can be obtained, and the molded product can be easily released from the mold.

[Embodiment 1] As shown in FIG. 1, a metal mold 3 having a simple cylinder portion and no special design such as a taper angle is used, and the diameter is about 10 mm and the height is about 5 mm.
The molded body of was produced.

The powder 2 used is 1 after crushing alumina.
Grain sized through a 00 mesh sieve, 3-40
It had a particle size distribution of μm. No binder or mold release agent was used. Further, the mold 3 was not coated with a release agent or the like except that it was cleaned with alcohol.

About 1.5 grams of the above powder 2 was charged from the upper part of the mold 3, and then the punch rod 1 of the uniaxial press machine was used.
The powder was pressed at a pressure of 1.5 t / cm. At this time, the mold 3 was reciprocated in parallel with the pressing direction at a rate of 0.2 to 10 times per second with a stroke of 5 mm from the start of pressing.

The non-uniformity of pressure was evaluated by the presence or absence of peeling of the molded product in a laminate form. The die-cutting property was evaluated by the maximum applied pressure of the pressing machine when the jig shown in FIG. 2 was used.

That is, after removing the upper punch bar 1,
While holding the die 3 with the die-cutting jig 5, the lower punch bar 1
Pushed up the green compact.

[0020]

[Table 1]

As shown in Table 1, in the method of the present invention in which the die is reciprocated, the maximum punching pressure applied to the lower punch bar 1 is as small as 50 to 80 kg, and the laminate-like peeling is performed once. Was not observed.

[Comparative Example] A molded body was produced in the same manner as in Example 1 except that the reciprocating motion of the mold was not performed at all.

As shown in Table 1, in the method of Comparative Example, the maximum die-applied pressure was as high as 200 to 400 kg, and the laminate-like peeling was observed in 80% of the samples.

[0024]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above in detail, it is possible to apply a uniform pressure to powder in a uniaxial press and to easily remove the molded product from the mold. It is very effective in improving the efficiency of the molding process and improving the yield.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a porcelain molding machine having a mold according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of the porcelain molding machine of FIG. 1 showing a place where a die cutting jig is applied.

[Explanation of symbols]

 1 Punch bar 2 Powder 3 Mold 4 Reciprocating direction 5 Die cutting jig

[Procedure amendment]

[Submission date] January 24, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

That is, the powder 2 is put in the space formed by the punch rod 1 and the die 3, and the punch rod 1 pressurizes the powder 2. Further, the mold 3 is shown in FIG.
As indicated by the arrow, the fine reciprocation is possible in parallel with the direction of pressing by the punch rod 1.

Claims (1)

[Claims] 1. A method for manufacturing a porcelain, comprising: a step of molding a powder obtained by crushing and sizing a raw material with a mold; and a step of heat-treating a molded body obtained by the method. A method for manufacturing a porcelain, characterized in that, when the powder is molded by pressurizing in a direction, the mold reciprocates in parallel to the pressing direction.