JPH07227818A - Cast molding and device therefor - Google Patents

Abstract

PURPOSE:To perform molding easily and efficiently after supplying a minimum required quantity of slurry for molding by pressing the slurry with the help of a solvent and an unblendable liquid in the slurry, when forming a molding in a molding die by allowing the solvent of the slurry to be absorbed into the molding die. CONSTITUTION:A molding is formed in a molding die 1 by supplying slurry into a liquid absorptive molding die 1, and at the same time, allowing a solvent in the slurry to be absorbed into the molding die 1. In this cast molding method, the slurry is pressed by the solvent and the unblendable liquid of the slurry after introducing the slurry into the molding die 1. That is, a dispensing pump 11 is activated by opening a valve 10, as a first step, to supply a specified quantity of slurry into the molding die 1, the upper part of a buffer tank 7 and piping 8 from a slurry tank 3. Next, a pump 18 is activated by opening a valve 17, then thereby, a pressurized air in a pressure accumulation tank 16 is supplied into a heavy liquid tank 13 to pressurize the surface of a heavy medium, and the slurry is pressurized through the heavy medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for casting various ceramics such as ceramics and an apparatus therefor, and more specifically, to pressurizing a slurry in which a ceramic raw material is dispersed in water or an organic solvent. The present invention relates to a cast molding method and apparatus improved in method.

[0002]

2. Description of the Related Art A cast molding method uses a mold made of a porous liquid-absorbent material such as gypsum, and a solvent of slurry injected into the mold is absorbed by the mold to obtain a desired material. To obtain a molded product having the above shape.

FIG. 3 is a schematic view showing a conventional casting method and apparatus, in which a slurry can be supplied from a slurry tank 3 to a liquid absorbing mold 1 through a pipe 2. A discharge pipe 4 is branched from the middle of the pipe 2.
The pipes 2 and 4 are provided with valves 5 and 6, respectively.

To perform molding, the valve 5 is opened and the valve 6 is closed, and the slurry is introduced into the molding die 1. In the slurry introduced into the molding die, the solvent therein is gradually absorbed by the molding die 1, so that the inner surface of the molding die is adhered (adhesion of solid content in the slurry). The slurry is newly supplied into the mold by the volume of the absorbed solvent, and the slurry is pressurized in order to increase the absorption rate of the solvent and increase the density of the inlaid matter. Normally, the head pressure (ΔH) of the slurry tank is used or the inside of the slurry tank is pressurized with air (see arrow P).

After the inside of the mold 1 is completely solidified (thickness), the valve 5 is closed and the valve 6 is opened, and the slurry remaining in the flow path between the valves 5 and 6 and the molded body is recovered. After that, the mold 1 is disassembled and the molded body is taken out.

[0006]

The conventional cast molding method has the following problems.

The solvent in the slurry that has accumulated near the pouring opening 1a of the molding die 1 is also absorbed by the molding die 1 (or the incarnation in the molding die), and a solidified product is formed near the pouring opening 1a. The solidified material in the vicinity of the pouring port 1a adheres to the obtained molded body in an ear-shaped burr shape, and it is necessary to perform a finishing treatment (deburring) on the molded body. Since a large amount of slurry is present in the vicinity of the mouth 1a during the molding process, the amount of burr-like solidified matter is large and the finishing process is troublesome.

In the pipe 2 in the vicinity of the casting port 1 a, the solvent in the slurry is absorbed by the molding die 1 and the molded body to increase the slurry concentration, and when the residual slurry is discharged from the pipe 4, the slurry is discharged. Is hard to flow.

When the discharged slurry is used again as a forming raw material, the discharged slurry is concentrated, and therefore the concentration and viscosity are different from those of the original slurry.

When slurries having different concentrations and viscosities are supplied to the molding die, the inking speed and the strength of the molded body vary, so that it is difficult to mold a molded body having a strength within an allowable range within a required time. Become. Therefore, it is expected to provide a casting device in which the discharged slurry is not concentrated.

[0011]

The casting method and apparatus of the present invention are characterized in that the slurry is pressurized by a liquid that is incompatible with the solvent of the casting slurry.

It is desirable that the liquid which is incompatible with the solvent of the slurry has properties such as different specific gravity from the slurry, a high boiling point, and a low vapor pressure. Further, the poorer the wettability with the inner surface of the flow path to the molding die and the material forming the molding die, the more convenient.

As means for pressurizing the liquid in order to pressurize and mold the slurry into the molding die, pressurization with compressed air or mechanical pressurization means such as a pump is suitable.

In the present invention, the constituent material of the mold may be gypsum, as well as liquid-absorbent ceramics, metal or synthetic resin. The mold may be entirely liquid-absorbent or partially liquid-absorbent.

There are no particular restrictions on the number and position of the casting ports, the shape of the molding die, and the like.

The slurry may be a ceramic powder slurry, a metal powder, a synthetic resin powder, or the like. The solvent of the slurry may be either water or an organic solvent. The slurry concentration is not particularly limited.

[0017]

Since the liquid that pressurizes the molding slurry is incompatible with the solvent of the slurry, only the molding slurry can be pressurized and injected into the molding die for molding.

[0018]

EXAMPLES FIGS. 1 and 2 are system diagrams of an example apparatus, in which a molding die 1 and a slurry tank 3 are communicated with each other through a buffer tank 7 and pipes 8 and 9. A valve 10 and a metering pump 11 are provided in the middle of the pipe 8. The pipe 8 is connected to the top of the buffer tank 7, and the pipe 9 is connected to a portion slightly below the top of the buffer tank 7.

The buffer tank 7 and the heavy liquid tank 13
The bottom part of is connected by a pipe 12. The heavy liquid tank 13 contains mercury as a liquid having a large specific gravity that is immiscible with water or an organic solvent. The upper part of the heavy liquid tank 13 is the pipe 1
It is connected to the accumulator tank 16 through 4, 15. In the middle of the pipe 14, from the heavy liquid tank 13 to the accumulator tank 16
Is provided with a pump 18 for sending air toward
A valve 17 is provided in the pipe 15.

To perform molding, the valve 1 as shown in FIG.
While opening 0, the metering pump 11 is operated for a predetermined time to supply a predetermined amount of slurry into the molding die 1. At this time, no pressure is applied to the liquid surface in the heavy liquid tank 13.

After a predetermined amount of slurry has been introduced into the upper part of the buffer tank 7, the pipe 8 and the molding die 1, the valve 1
Close 0. Then, the valve 17 is opened and the accumulator tank 1
The pressurized air in 6 is supplied into the heavy liquid tank 13,
The liquid surface of the heavy liquid in 3 is pressed. As a result, the slurry in the buffer tank 7 is gradually fed into the molding die 1. By pressurizing the slurry with a heavy liquid, absorption of the solvent in the slurry into the mold 1 is promoted.

As shown in FIG. 2, the molding is stopped with the heavy liquid having entered the casting port 1a. It should be noted that the slurry concentration, the size of the molding space of the molding die 1, and the volume from the upper portion of the buffer tank 7 to the pipe 8 are set so that a molding having a required strength is formed in the molding die 1 when the molding is stopped. It has been selected.

To take out the molded product from the state shown in FIG. 2,
The valve 17 may be closed, the mold 1 and the pipe 8 may be separated, and the mold may be removed.

After the demolding, the pump 16 is operated to send the air in the heavy liquid tank 13 into the pressure accumulating tank 16. As a result, the heavy liquid in the pipe 8 returns to the buffer tank 7,
Moreover, the heavy liquid level in the buffer tank 7 is lowered to the state shown in FIG. Therefore, the pump 16 is stopped, a new molding die 1 is connected to the pipe 8, and molding of the next lot is started.

Next, specific examples and comparative examples will be described.

Example 1 Commercially available alumina powder (Showa Denko AL-160SG) 5
000 g, polycarboxylic acid type dispersant (D-3 manufactured by Chukyo Yushi Co., Ltd.
05, solid content 40%) 25 g, binder (solid content 50
%) And 1210 g of pure water were mixed in an alumina ball mill to obtain a molding slurry having a slurry concentration of 80%.

The casting molding apparatus shown in FIG. 1 and the internal dimension φ
Using a plaster mold 1 of 150 × 10 mm, pressure casting was carried out at a molding pressure of 2 kgf / cm ² through mercury. The relative density of the obtained molded body was 60%, and the molded body was fully solidified including the burr portion.

Comparative Example 1 Pressure cast molding was carried out in the same manner as in Example 1 except that the conventional cast molding apparatus shown in FIG. 3 was used. The relative density of the obtained molded product was 60%, and the end of the burr portion of the molded product was in the form of mud.

[0029]

As described above, according to the casting molding method and apparatus of the present invention, the slurry can be pressed and molded by the liquid which is incompatible with the solvent of the molding slurry. Therefore, the minimum required slurry for forming is supplied to obtain a formed body, and the labor for loss, recovery, and reuse of the slurry is greatly improved. Further, since a constant amount of slurry can be constantly supplied to the molding, the shape of the molded body is stabilized and the post-process is facilitated. Furthermore, the automation of molding becomes easy, and it is expected that the productivity will be comparable to that of injection molding, especially for small products.

[Brief description of drawings]

FIG. 1 is a system diagram showing an example apparatus.

FIG. 2 is a system diagram showing an example apparatus.

FIG. 3 is a system diagram showing a conventional cast molding apparatus.

[Explanation of symbols]

 1 Mold 3 Slurry tank 7 Buffer tank 13 Heavy liquid tank

Claims (2)

[Claims] 1. A slurry is supplied into a liquid absorbing mold,
In a casting method in which a solvent in a slurry is absorbed by the mold to form a molded body in the mold, after introducing the slurry into the mold, a liquid immiscible with the solvent in the slurry is used. A cast molding method comprising pressurizing the slurry. 2. A casting molding apparatus having a liquid absorbing casting mold and a slurry storage first tank connected to the casting mold via a slurry supply pipe, wherein a solvent in the slurry is used. And a second tank for storing a liquid immiscible with the second tank, the second tank and the middle of the pipe are communicated with each other, and the liquid is pressurized and supplied from the second tank to the pipe. A casting molding apparatus, which is provided with a means for