JPH06246716A - Slip casting mold - Google Patents

Abstract

PURPOSE:To enhance the continuous moldability of a molded object and to reduce the wastefulness of slip by providing a replacement casting mold having a runner whose inner wall is coated with a sealant blocking a solvent in opposed relation to a hollow part molding the molded object. CONSTITUTION:A hollow part 1e is provided to an upper casting mold 1a and the freely detachable replacement casting mold 1b fitted in a lower casting mold 1c is provided. A runner 1d whose inner wall is coated with a sealant is provided to the casting mold 1c and the hollow part 1e so as to piece the casting mold 1c in an up-and-down direction and the deposition of ceramics to the runner 1d is prevented. When a deposition layer excessively extends to the casting port part 1f of the runner 1d when a ceramics molded object 32 is molded in the hollow part 1e, the replacement casting mold 1b is replaced and the excessive deposition layer is removed from the casting mold 1 and next molding immediately becomes possible and continuous molding becomes possible. By making the length of the runner 1d of the replacement casting mold 1b and that of the excessive deposition layer as same as possible, the amt. of the slip remaining in the runner 1d is reduced and the wastefulness of the slip can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slip casting mold used in a pressure slip casting method.

[0002]

2. Description of the Related Art A slip casting method (slurry casting method) is known as a method for molding ceramic products using ceramic powder. With the slip casting method, ceramic powder dispersed in a solvent such as water is poured into a mold made of an absorbent material such as gypsum to absorb the solvent and only the solid content of the slurry is applied to the inner wall of the mold. This is a method in which the ceramic body is molded into a predetermined shape by inking, and the molded ceramic body is removed from the mold. This slip casting method is known as wet near net shape molding method,
It is generally applied when manufacturing fine ceramics and the like. Since the mold used in the slip casting method is made of an absorptive material such as gypsum, it is possible to obtain a ceramic molded body only by pouring sludge into the mold. However, mass pouring is poor because it takes time to obtain a ceramic compact simply by pouring sludge into the mold. For this reason, a pressure slip casting method is applied to mass-produced products in which sludge is pressed to improve the inking rate.

FIG. 4 is a sectional view of a conventional mold for molding a ceramic molded body, and FIG. 5 (a) is a front view of the ceramic molded body molded by the mold shown in FIG.
FIG. 5B is a view seen from the AA direction in FIG.
This mold 30 is a first mold 30 which is combined with each other.
It is composed of a and a second mold 30b. First
The mold 30a is provided with a hollow portion 30d in which the disc-shaped ceramic molded body 32 shown in FIG. 5 is molded. On the other hand, the second mold 30b is provided with a runner 30c through which a slurry (not shown) is fed into the hollow portion 30d. Also, this runner 30c is the second mold 30.
The portion which penetrates b and intersects with the hollow portion 30d is the casting port 30.
It is called e. The disk-shaped ceramic molded body 32 shown in FIG. 5 has a diameter of 100 mm and a thickness of 10 mm.

FIG. 6 is a schematic view of a conventional pressure slip casting apparatus equipped with the mold shown in FIG. This pressure slip casting device is a sludge (not shown)
The sludge container 3 in which is stored and the transport pipe 3
And a mold 30 connected by 6. An air compressor (not shown) and a vacuum pump (not shown) are connected to the sludge container 3. This air compressor pressurizes the sludge through a pipe 6 provided with a valve 8, a meter 7 and a leak valve (not shown). Further, this vacuum pump is for defoaming the sludge before it is pressurized by the air compressor through a pipe 9 provided with a valve 11, a meter 10 and a leak valve (not shown). One end of the transport pipe 36 is connected to the sludge container 3, and the other end is connected to the runner 30c of the second mold 30b. In addition, the transport pipe 36 has three valves 5, 40, 4
Two are provided. In addition, when the slurry is pumped, the mold 3
In No. 0, the first mold 30a and the second mold 30b are clamped by a mold clamping machine (not shown).

This pressure slip casting device is
The transport pipe 36 is obtained by pressurizing the sludge (not shown) stored in the sludge container 3 with an air compressor (not shown).
And the hollow portion 3 via the runner 30c of the mold 30
It is pressure-fed to 0d. During this pressure feeding, the valve 5 and the valve 40 of the transport pipe 36 are opened and the valve 42 is closed. The ceramic molded body 32 shown in FIG. 5 is molded by depositing the pressure-fed sludge on the inner wall of the hollow portion 30d. At the time of this molding, whether or not the molding of the ceramic molded body 32 is completed cannot be visually judged because the inside of the mold 30 cannot be seen during molding, and the inking rate of ceramics is strictly different for each molding. Therefore, it is difficult to make the finish line of the inking layer completely the same every time, and it is not possible to completely judge by time whether or not the molding of the ceramic molded body 32 is completed. Therefore, a plurality of ceramic molded bodies 32 are molded in advance, and by this molding, the approximate time required for molding the ceramic molded bodies 32 is determined. During this time, before the molding of the ceramic molded body 32 is completed, the ceramic molded body 3 is
Since the ceramic molded body 32 becomes a defective product when the mold 2 is demolded, the ceramic molded body 32 is extended from the ceramic molded body 32 with a margin and at least the time until the sludge is excessively inlaid up to the casting opening 30e. And The excess sludge from the ceramic molded body 32 to the pouring port 30e is also hard on the inner wall of the runner 30c. The mold 30 is removed from the mold clamping machine (not shown) after the completion of the molding of the ceramic molded body 32 in which the slurry is excessively thickened to the pouring port 30e, and the first mold 30
a is released from the second mold 30b, and the ceramic molded body 32 is released from the mold. After this demolding, the casting port 30e
The infiltration layer of the sludge that has been infiltrated into the runner 30c including is an obstacle to the subsequent pumping of the slurry, and is removed by being dug out or extruded. The removed inking layer is washed with water or the like from the pressure slip casting device and then poured out. In order to prevent water and the like from being mixed in the slurry in the transport pipe 36 at the time of this flow out, the water is flowed out after the valves 5 and 40 are closed and the valve 42 is opened. After that, the subsequent molding of the ceramic molded body 32 is performed by the same method as described above. In addition, the casting port 30
The sludge excessively thickened up to e also partially adheres to the demolded ceramic compact 32, but the adhered sludge is scraped off from the ceramic compact 32.

[0006]

In the above-mentioned conventional technique, when the inking layer of the runner 30c including the spout portion 30e is removed, the inking layer is hard, so it must be dug out or extruded. However, there is a problem that it takes time and effort until the next molding, which deteriorates the continuous moldability of the ceramic molded body. Further, when the removed inking layer is poured out from the pressure slip casting device, the sludge remaining in the runner 30c and the transport pipe 3 between the runner 30c and the valve 42.
Since the sludge in 6a is washed out together with water, there is a problem that the sludge is wasted a lot.

In view of the above circumstances, it is an object of the present invention to provide a slip casting mold which improves the continuous formability of a ceramic molded body and reduces waste of sludge.

[0008]

In the slip casting mold of the present invention for achieving the above object, the pressed slurry is pressure-fed to the hollow portion through the runner to form a ceramic molded body. In the slip casting mold, a sealant that penetrates the runner and blocks the solvent contained in the slurry is applied to the inner wall of the runner, and a detachable replacement mold is provided facing the hollow portion. To do.

[0009]

The slip casting mold of the present invention is equipped with a detachable exchange mold at the portion where the sludge excessively adheres to the runner. Therefore, the mud deposit layer is formed after the ceramic molded body is demolded. By replacing the exchange mold remaining in the runner with another identical exchange mold, the next molding can be started immediately, and the continuous moldability of the ceramic molded body can be improved. In addition, the amount of sludge remaining in the runner of the exchange mold that has been exchanged is smaller than the amount of sludge remaining in a part of the transport pipe and discharged from the pressure slip casting device, so there is less waste of sludge. Become. In addition, the inner wall of the runner of the exchange mold is coated with a sealant that shuts off the solvent, so that the sealant does not cause the inking layer to adhere to the runner, which causes the ceramic molded body to demold. After that, the inking layer remaining on the runner can be easily removed.

[0010]

EXAMPLES Examples of the present invention will be described below. FIG. 1 is a cross-sectional view of a slip casting mold according to an embodiment of the present invention. It should be noted that redundant description with the conventional mold (see FIG. 4) is omitted. This slip casting mold 1 is composed of an upper mold 1a on the upper side in FIG. 1, a lower mold 1c on the lower side in FIG. 1, and a removable replacement mold 1b fitted to the lower mold 1c. is there. The upper mold 1a is provided with a hollow portion 1e, and the lower mold 1e
The c and the exchange mold 1b are provided with a runner 1d having a sealant (not shown) applied to the inner wall thereof penetrating them in the vertical direction in FIG. This sealant does not absorb a solvent such as water in the runway 1d.
Ceramics are prevented from being deposited on d. This slip casting mold 1 is molded from gypsum, and Table 1 shows its characteristics. The ceramic molded body molded by this slip casting mold 1 is the same as the ceramic molded body 32 shown in FIG. 5, and the length of the runner 1d portion of this exchange mold 1b is 10 mm.

[0011]

[Table 1]

FIG. 2 is a schematic view of a pressure slip casting apparatus equipped with the slip casting mold shown in FIG. It should be noted that redundant description with the conventional pressure slip casting apparatus (see FIG. 6) is omitted. The pressure slip casting apparatus includes a sludge container 3 and a slip casting mold 1 connected to the sludge container 3 via a transport pipe 4. The transport pipe 4 is provided with a valve 5.

Ten replacement molds 1c were prepared for molding the ceramic compact 32 shown in FIG. 5 using the pressure slip casting apparatus shown in FIG. As the slurry used in this example, Al ₂ O ₃ (alumina) slurry (not shown) was used. This Al ₂ O ₃ slurry is 100% Al ₂ O ₃ powder having a mean particle size of 0.8 μm as a ceramic powder.
Parts by weight, 20 parts by weight of water as a solvent, and 0.4 parts by weight of a dispersant (Chukyo Yushi D-305) were mixed and stirred, and ball-milled for about 10 hours using a nylon pot and nylon balls. Later, 2 parts by weight of acrylic emulsion (Mitsui Toatsu WA320) was added as a binder to obtain a molding slurry.

FIG. 3 is a diagram showing a process of molding a ceramic molded body using the slip casting mold of this embodiment. The process shown in FIG. 3 was repeated 10 times to form Al ₂
A ceramic molded body was molded using O ₃ slurry.
The results are shown in Table 2.

[0015]

[Table 2]

Here, the surplus infiltration layer length is the infiltration layer cast
This is the length that extends excessively to the opening 1f and is the
Is the replacement mold 1b for the next molding, etc.
Say the time needed for. As shown in Table 2, within the runway 1d
A solvent sealant (not shown) is applied to the walls.
As a result, the inner wall of the runway 1d was not infiltrated with sludge.
Therefore, the excess layer thickness is in the range of 2.0 to 3.5 mm.
It was The length of the runner 1d of this exchange mold 1b is 10 mm.
Therefore, the surplus infiltration layer length in the above range is the hot water of the replacement mold 1b.
It is less than or equal to the length of the path 1d, so that the exchange mold 1b
By exchanging, the surplus inking layer can be excluded from the mold 1, and immediately
The following molding could be performed. Also, this exchange mold 1b
When it is replaced, the lower mold 1c below it will have about 0.2 cc
Al₂ O₃ The mud flowed out. But this flowed out
Since the amount of slurry is extremely small, the surface of the lower mold 1c
Wipe off with a sponge (not shown) etc.
The sludge that had come out could be removed immediately and easily. It
Cleaning the replacement mold 1b taken out from the
A thin metal bar (not shown)
Easily extrude the surplus infiltration layer with () and wash it with water.
It could be washed more easily and removed immediately. Ceramics composition
During the molding of the shape 32, the replacement mold 1b is moved to the mold clamping machine (not shown).
No.) was sandwiched between the upper mold 1a and the lower mold 1c.
Therefore, ceramics do not come off even during pressure molding
There was no problem in molding the molded body 32. Conclusion of this example
Fruit, Al ₂ O₃ There is very little waste of sludge and it is possible to connect efficiently.
Continuous molding is possible, and the interval between moldings is as shown in Table 2.
It was about 30 seconds.

Comparative Example For comparison, in the conventional pressure slip casting apparatus shown in FIG. 6, the same Al ₂ O ₃ slurry as in this example was used to mold the ceramic compact 32. As a result, about 10 cc of Al is discharged from the valve 42 (see FIG. 6) after the molding of the ceramic molded body is completed.
₂ O ₃ sludge was discharged. After this, a metal rod (not shown) is used to inject the hard excess layer from the pouring port 30e of the second mold 30b (see FIG. 6) with a metal rod (not shown), and the hard excess layer is poured out with water and brushed. Transport pipe 36 (not shown)
The inside of a (see FIG. 6) was washed. Because of these tasks,
The ceramic molding interval took about 10 to 15 minutes. In this way, comparing the present invention with the prior art, it can be seen that the prior art involves a large amount of sludge and poor ceramic continuity.

Here, it is also possible to automatically mechanize the molding of the ceramic molded body 32 using the mold 1 for pressure slip casting of the present invention. That is, it is possible to repeat the steps of pressure molding → demolding → replacement of the replacement mold 1b, wiping and removing sludge → the next pressure molding, and to continuously perform the same. It suffices to deal with it by using a plurality of molds. Further, when replacing the replacement mold 1b, a plurality of replacement molds 1b may be cleaned and reused in parallel with the continuous molding of ceramics to improve the continuous moldability of the ceramic molded body. it can.

Further, by making the length of the runner 1d of the replacement mold 1b and the length of the surplus inking layer as much as possible, the replacement mold 1b
The amount of sludge remaining in the runner 1d can be made as small as possible, and the waste of sludge for each molding can be made extremely small. Further, the mold 1, sludge and the like used in the present invention are not limited in shape and material as long as they are suitable for the pressure slip casting method. Further, the pressure source and pressure for pressing the sludge are not limited as long as the pressure slip casting method can be performed.

[0020]

As described above, the slip casting mold of the present invention is provided with the detachable exchange mold provided with the runner. Therefore, by exchanging the exchange mold, the ceramics can be melted. Even if it remains, the continuous moldability of the ceramic molded body can be improved. In addition, the amount of sludge that remains in the runner and is discarded is extremely smaller than the amount of sludge that is discarded from the conventional pressure slip casting device, and the waste of sludge can be reduced. Further, since the sealant is applied to the inner wall of the runner of the replacement mold, the inking layer extending to the runner does not adhere to the inner wall of the runner, which facilitates cleaning of the replacement mold.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a slip casting mold according to an embodiment of the present invention.

FIG. 2 is a schematic view of a pressure slip casting apparatus including the slip casting mold shown in FIG.

FIG. 3 is a diagram showing a process of molding a ceramics compact.

FIG. 4 is a cross-sectional view of a conventional example of a mold for molding a ceramics compact.

FIG. 5 is a front view (a) of a ceramics molded body molded by the mold shown in FIG. 4, and a view (b) viewed from the AA direction in (a).

FIG. 6 is a schematic view of a conventional pressure slip casting apparatus equipped with the mold shown in FIG.

[Explanation of symbols]

 1 Slip casting mold 1a Upper mold 1b Exchange mold 1c Lower mold 3 Sludge container 4 Transport pipe

Claims (1)

[Claims] 1. A slip casting mold having a hollow portion in which a slurry in which ceramic powder is dispersed in a solvent is sent through a runner to form a ceramic molded body, wherein a sealing agent for blocking the solvent is an inner wall. A slip casting mold comprising: a removable exchange mold facing the hollow portion, through which the runner applied to the mold penetrates.