JPH0999418A - Manufacture of ceramic member and molding method for ceramic powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a ceramic member which can easily mold the member having a complicated three-dimensional curved surface at a high speed, and a method for molding ceramic powder. SOLUTION: This method for manufacturing a ceramic member comprises the steps of filling a granulated powder 3 previously prepared in composition in an extra-thin hollow plastic vessel (body 14 and upper cover 15) having elasticity and molded in shape and size previously on the basis of a molding margin in later steps wile vibrating it by an exciter 19, pressing it by upper and lower molds 18, 21, and then sealing it by a thermally pressing ring 23 under reduced pressure by a suction pump 22 via an air bleeding hole 15-2.

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 a ceramic member and a method for molding a ceramic powder, and is particularly useful when applied to a member having a three-dimensional curved surface, for example, a ceramic manufacturing process such as a turbine blade or an engine valve. It is a thing.

[0002]

[Prior art]

(1) A conventionally known method for molding ceramic powder. As shown in FIG. 9, various methods are conventionally known.
That is, in system A, which is formed after kneading a granulated powder (powder whose composition has been adjusted) with a plastic medium or fluid, extrusion molding (adding a plasticizer and extruding from a die), injection molding (thermoplastic resin) Kneading and extruding into a mold)
There is a slip cast method (granular powder in the form of slurry is poured into a stone mold to absorb and remove the medium into the mold). On the other hand, in the system B in which the granulated powder is directly molded, there are a rubber pressing method (filling a rubber mold with the granulated powder and applying water pressure), a pressure molding method (pressing with a vertical punch in a mold), and the like.

(2) A method for molding ceramic powder, which has been proposed by the present inventors. In contrast to the conventionally known method for molding ceramic powder as described in (1) above, the method for molding ceramic powder previously proposed by the present inventors is as shown in FIGS. It was a molding method. That is, after the granulated powder 3 is held in shape by pressing with the upper die 5 in the die 4 shown in FIG. 13, an organic resin film having elasticity on its outer surface, for example, as shown in FIG. This is a method of molding a ceramic powder in which CIP (low temperature isostatic pressing) is performed after sealing the entire outer surface of the member with a mold resin. In the figure, 6 is a lower mold, 7 is a resin melt, 8 is a heating tank, 9 is a pump with a constant feed mechanism, 10 is a heater, 11 is a heating mold, 12 is a resin layer, and 13 is a work lifting mechanism. .

[0004]

However, the above-mentioned conventional method for molding ceramic powder has the following problems.

(1) Problems of Conventionally Known Ceramic Powder Forming Methods The various forming methods shown in FIG. 9 have their respective advantages and disadvantages. For example, in the system A, the extrusion molding method determines the product shape by the die shape, and can only produce a product having a two-dimensional surface shape such as a round bar, a square bar, or a modified cross-section bar. In the injection molding method, since it is necessary to form the weir portion which becomes the injection path into the mold every time, a loss material that does not become a product is produced, and the yield of expensive ceramic raw material is poor. In the slip cast method, it takes a long time to absorb and dry the medium (liquid) of the slurry injected into the stone mold, and the productivity is low.

On the other hand, in the B system, although the rubber mold is an elastic body in the rubber pressing method, since the thickness of the rubber is large, the rubber pressure has a non-uniform behavior in a place where the radius of curvature is small. In particular, it is poor in imparting uniform surface pressure and shape conformability to a product having a small and complicated three-dimensional curved surface. The pressure molding method can handle complicated three-dimensional product shapes by using a mold with a complicated shape. However, in the case of a product shape whose length (height) in the pressing direction is larger than the cross section, the molded body is Because it is powder,
There was a drawback that it was difficult to achieve uniform compression and uniform density. In such a case, the dimensional change in the low density region is large at the time of firing in the subsequent step.

The problems of the conventional molding method described above are summarized as follows. Being able to easily and rapidly mold 3D curved products. In order to maximize the yield of ceramic raw materials, it is not necessary to mold members other than the product shape (such as weirs and injection ports). A uniform packing density should be obtained at the molding stage in order to obtain uniform shrinkage, density, strength, etc. without deformation during firing in the subsequent process. Be able to process a large amount in the molding process. It should be possible to obtain a molding strength that can withstand the member holding force and external processing force during machining in the next step.

(2) Problem of the method for forming a ceramic powder which has been proposed by the present inventors. In this forming method, as shown in FIG. 13, after the granulated powder 3 is shaped and shaped in the die press 4. As shown in FIG. 14, the whole outer surface was covered and sealed with an organic resin, and thereafter, as shown in FIG. 8, a large amount of the powder was processed in a CIP (low temperature isostatic press) device. Therefore, the above ~
The method is a mass production method that solves the above problem. However, for example, molding of the concave portion of the cotter groove 1-1 of the engine valve of FIG. 10 and the convex portion of the connecting portion 2-1 of the turbine blade shown in FIG. When molding with a die press, considering the releasability from the die, it is difficult to use an integrated die, and if a split die is used, the die design becomes complicated and expensive, and there is a problem in terms of die accuracy. there were. When the cotter groove 1-1 is not formed at the time of die pressing and is formed by a later machining process, a small amount and a lid cause a loss in the expensive ceramic raw material. Also, in mass production lines for engine valves and the like, it is extremely important to omit processes, make external setups, and reduce man-hours in the process from the viewpoint of drastically reducing manufacturing costs. The number of steps is still large, such as the filling and shape-retaining process by →, the organic resin sealing process → the CIP process, and further reduction is necessary.

In short, further improvement of three-dimensional modeling property and improvement of raw material yield. Further omission of processes and reduction of man-hours. The development of a construction method to achieve

Accordingly, the present invention provides a method for manufacturing a ceramic member and a method for molding ceramic powder, which can solve the above problems.

[0011]

[Means for Solving the Problems] A method for manufacturing a ceramic member for solving the above-mentioned problems is described in a hollow ultra-thin plastic container having elasticity formed in advance in a shape and size in consideration of a molding allowance in a subsequent step. After filling the granulated powder whose composition has been adjusted in advance and simultaneously sealing the granulated powder charging opening of the hollow plastic container under reduced pressure, the plastic container and the plastic container are uniformly densified by low temperature isostatic pressing. It is characterized in that it is subjected to a treatment, and further subjected to shaping machining before firing, firing, and partial polishing finish.

The first ceramic powder molding method for solving the above-mentioned problems is a shape / molding method that takes into account the molding allowance in the subsequent step.
In the molding step of filling the granulated powder having a composition adjusted in advance in a hollow plastic container having an elasticity and formed into a size and having a composition adjusted at the same time, the granulated powder charging opening of the hollow plastic container is sealed under reduced pressure. As a method of filling the hollow plastic container with granulated powder, the granulated powder charging opening of the hollow plastic container is depressurized at the same time as pressing with an upper mold in a mold that holds the outer periphery of the hollow plastic container in contact with the hollow plastic container. It is characterized by being sealed under.

The second ceramic powder molding method is as follows:
The granulated powder with the composition adjusted in advance is filled in the ultra-thin hollow plastic container having elasticity and formed into the shape and size that takes into account the molding allowance in the subsequent step, and at the same time the granulated powder in the hollow plastic container is charged. In the molding step of sealing the opening under reduced pressure, as a method of filling the hollow plastic container with the granulated powder, the granulated powder is charged and filled while vibrating the hollow plastic container and the hollow plastic container is It is characterized in that the granulated powder charging opening is sealed under reduced pressure.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings (FIGS. 1 to 8).

FIG. 1 is a whole process diagram for producing a ceramic product having a complicated shape by following the forming process according to the present invention, and FIG.
(A) is a cross-sectional view of a hollow plastic container (capsule) used in the ceramic molding process according to Example 1 of the present invention,
2 (b) is a view taken along the line AA of FIG. 2 (a), and FIG. 3 (a).
3 is a cross-sectional view of a hollow plastic container (capsule) used in the ceramic molding process according to Example 2 of the present invention, FIG.
3B is a view taken along the line BB in FIG. 3A, and FIG. 4 shows a state in which the granulated powder is vibrated, filled and sealed in the hollow plastic container in the ceramic molding process according to Example 1 of the present invention. FIG. 5 is a sectional view showing a state in which the filling and sealing of the granulated powder into the hollow plastic container is completed in the ceramic molding process according to the first embodiment of the present invention, and FIG. 6 is a second embodiment of the present invention. FIG. 7 is a cross-sectional view showing a state in which the granulated powder is press-filled and sealed in the hollow plastic container in the ceramic molding process, and FIG. 7 shows the filling / sealing in the hollow plastic container in the ceramic molding process according to the first embodiment of the present invention. Sectional view showing the state
FIG. 8 is a cross-sectional view showing a state in which a hollow plastic container filled with granulated powder and hermetically sealed is subjected to a large amount of processing at one time by CIP (low temperature isostatic pressing).

As shown in FIG. 1, the outline of the forming step S using the ceramic forming method according to the present invention is the first step S.
After filling the thin-walled plastic resin container with the granulated powder in 1 and hermetically sealing, the CIP (low temperature isostatic pressing) is performed in the second step S2. Specifically, the following means are sequentially taken as a forming method in the pre-firing step of ceramics.

[Means 1] ... As shown in FIG. 2 or FIG. 3, the resilience is preliminarily formed into a shape and size in consideration of the molding allowance in the subsequent steps, that is, the machining allowance before firing, the shrinkage allowance during firing and the like. As an extremely thin hollow plastic container (the material may be opaque, but preferably transparent or translucent so that the contents can be seen through during the subsequent filling process, for example, vinyl acetate, polystyrene, etc.), The container main body 16 or 14 and the upper lid 17 or 15 are prepared independently of the ceramic production line (outer preparation). An air vent hole is provided in either one of the main body 16 or 14 or the upper lid 17 or 15 (in the illustrated example, the air vent holes 17-2, 15-2 are provided in the upper lids 17, 15).
Are respectively provided). Although not shown, the main body and the upper lid may be integrally formed without being divided, and the air vent hole may be formed to be slightly larger to serve also as a granulated powder injection port described later.

[Means 2] ... As shown in FIG. 4 or 6, the container body 16 or 14 is filled with the granulated powder 3 whose composition has been adjusted in advance while pressing or vibrating, and the body 16 or 14 is filled. Then, seal joining (fusion welding by hot sealing or bonding by hot melt or the like) is performed at the flange portions 16-2, 17-1 or 14-2, 15-1 of the upper lid 17 or 15. 17-3 and 14-3 in FIGS. 5 and 7 are seal joints.

[Means 3] ... As shown in FIG. 4 or 6, the suction port 28 is pressed against the air vent hole 17-2 or 15-2 of the upper lid 17 or 15 and remains between the granulated powders filled in the container. The air in the minute cavity is sucked and the air vent hole 17-2
Alternatively, 15-2 is hermetically sealed (sealed with hot seal or hot melt adhesive, etc.) (17-4, 15- in FIGS. 5 and 7).
4). In order to prevent the granulated powder 3 from being sucked at the same time when sucking from the air vent hole 17-2 or 15-2,
A filter such as a non-woven fiber is finely packed in the air vent holes 17-2 and 15-2 in advance.

[Means 4] ... As shown in FIG. 5 or 7, a granulated powder-filled capsule body 36A or 36B in which the granulated powder 3 is enclosed in a thin plastic container having elasticity is shown in FIG. A large amount of low temperature hydrostatic pressure is applied to the device and pressure is applied (density homogenization + integration).

[Means 5] ... The CIP-pressed granulated powder-filled capsule body 36A or 36B is fired by a cutting machine in consideration of the peeling of the container and the shrinkage amount at the time of firing to remove the portion which becomes a fat meat. Finish to the size and shape of the previous Nearest Net Shape.

[Means 6] ... Then, the steps of baking and finish polishing (only necessary portions) are performed to complete the process.

Next, the molding process carried out by using the molding method of the present invention will be described. As an example of a ceramic product having a three-dimensionally complicated shape, there is an engine valve 1 shown in FIG. 10, a turbine blade 2 shown in FIG. 11 and the like. In the following examples, a method for manufacturing an engine valve will be described in detail.

As a raw material, silicon nitride (Si
₃ N ₄ ), yttria (Y ₂ O ₃ ), alumina (Al ₂
O ₃ ), other raw material powders were blended at a predetermined ratio, solvent wax was blended, and the granulated powder was distributed and kneaded. As for the target engine valve, the finished product size is the umbrella diameter:
The length was 35.0 mm, the shaft diameter was 7.5 mm, and the total length was 120 mm.

<First Embodiment> An explanation will be given with reference to FIGS. 2, 4 and 5. As a plastic container to be a capsule, a large number of a main body 16 (with identification mark 16-3) and an upper lid 17 shown in FIG. 2 having a thickness of 0.15 mm were prepared in advance using a vinyl acetate resin. (External setup)

Next, as an apparatus for carrying out the process shown in FIG. 4, vibrating bases 24 with vibrators 25 are arranged at positions of six divisions on a rotary table having a diameter of 1200 mm, and the vibrating bases 24 are intermittently moved by 60 °. Turn. Immediately above the vibration base at the rotary table stop position, there is an upper mechanism (fixed without turning) that has the operation functions of the following six steps.

Station (I): Main body supply loader ...
A manipulator for loading and placing the plastic container body 16 on the vibration base 24. Station (II): Granulated powder constant feeding mechanism ... A hopper 26 that moves up and down by measuring a fixed amount from the granulated powder supply tank at the top.
A mechanism for supplying the granulated powder to the plastic container body 16 via the. 3-1 in the figure is granulated powder in the hopper 26, 3-2
Is a granulated powder that is being supplied into the main body 16, and 3 is a granulated powder that is supplied into the main body 16. At the time of filling the granulated powder, the vibrator 25 is operated. (FIG. 4 (II)) Station (III): Top lid supply loader ... An elevating mechanism that loads the top lid 17 and loads and pushes it onto the end of the main body. (Fig. 4 (III
)) Station (IV): Seal joining mechanism ... Grips and presses the flange portions 16-2 and 17-1 in which the main body 16 and the upper lid 17 overlap.
Sealing mechanism (in the present embodiment, a heat sealing method using a pair of upper and lower heating and pressing jigs 27 is adopted). (Fig. 4
(IV)) Station (V): Suction / sealing mechanism ... Suction pump 22
And a seal heater 29 for heating and gripping the pipe-shaped protrusion 17-2 as an air vent, which is vertically connected to the rubber suction port 28. (FIG. 4 (V)) Station (VI): unloader ... A manipulator that carries out the capsule body filled with the granulated powder from the vibration table 24.

Using the above rotary table, about 5
With a cycle time of seconds, a granulated powder-filled capsule body 36A as shown in FIG. 7 was continuously produced. These are randomly placed in the treatment basket, placed in the CIP device shown in FIG. 8 (that is, set in the multi-stage arrangement jig 35), and the pressurized medium (normal temperature water) 34 is injected into the high-pressure container 30 from the inlet 32. While the air 3
After releasing 7, the air vent valve 33 of the upper lid 31 was closed to increase the pressure of the medium (1500 kg / cm ² ).

The C / capsule body obtained by the above procedure was subjected to N / C machine tool removal of the plastic container and removal of the extraneous flesh in consideration of the amount of shrinkage during firing.
A green ceramic in the shape of Shape was obtained.

Subsequently, heating and firing were performed, and finish grinding was performed on a part of a main part using a grinder.

<Second Embodiment> An explanation will be given based on FIGS. 3, 6 and 7. As a plastic container to be a capsule, a large number of main bodies 14 and upper lids (with identification marks 15-3) 15 shown in FIG. 3 having a thickness of about 0.15 mm were prepared in advance in a separate process using vinyl acetate resin. The shape of the shaft of the container body 14 was previously set to an entasis (medium thick column) shape as shown in FIG. 7B. In setting the entasis shape, the axial transmission distribution of the granulated powder compressive load by the upper and lower molds 18 and 21, the packing density, and the shrinkage rate during firing were set by computer analysis and elemental experiments.

As in the first embodiment, the filling and sealing apparatus was a rotary table type having a diameter of 1200 mm, and the stations were a total of 6 stations including loading and unloading in addition to the items below.

Insert the container body 14 into the mold 18. The granulated powder 3 is injected into the container body 18 and vibrated. The upper lid 15 is loaded, the granulated powder 3 is compressed by the upper mold 21, and the collar portions 15-1 and 14-2 are sealed. The inside of the container is depressurized through the air vent hole 15-2 and, at the same time, the air vent hole 15-2 is hermetically sealed.

Using the above rotary table, about 5
With a cycle time of seconds, the granulated powder-filled capsule body 36B shown in FIG. 5B was continuously produced. Below, a ceramic engine valve was completed in the same procedure as in Example 1 above.

The machining accuracy for the entasis portion after CIP is important, and an N / C machine tool was used.

<Operation / Effect> [Operation] As shown in FIGS. 2 and 3, the outer shell of the intermediate product can be formed by the ultrathin hollow plastic body 14 or 16 and the upper lid 15 or 17. The shape can be maintained even if the granulated powder 3 is filled in the subsequent step. Further, when molding the plastic container, for example, identification marks (protrusion symbols) 15-3, 16 are formed on the surface of the umbrella portion 1-2 of the engine valve 1 shown in FIG.
-3 can be formed, and the cotter grooves 14-1 and 16-1 are formed on the shaft portion.
It is also possible to form a concave shape that becomes Air vent holes 15-2 and 17-2 for venting air immediately after sealing after filling the granulated powder can be formed.

[Operation] As shown in FIG. 6, after the container body 14 is inserted into the lower mold 18 that fits the outer periphery of the plastic container body 14, the granulated powder 3 is shaken by the vibrator 19 while vibrating. Since it is filled, the filling rate is increased and the upper die 21
Since it is pressed by the upper lid 15 via, the packing density is further increased. Further, the collar portion 14-2 of the main body 14 and the collar portion 15 of the upper lid 15
-1 Heating press ring 23 when it overlaps (elevating type)
The granulated powder 3 can be enclosed in the hollow container (capsule) by performing the seal joining with. On the other hand, in the method shown in FIG. 4, the mold is not used, and the plastic container body 16
Is loaded on the vibration table 24, and the granulated powder 3 is supplied while being excited by the vibrator 19 (see FIG. 4 (II)).
The granulated powder 3 can be filled uniformly and with high density all over the container. The granulated powder 3 can be enclosed in a capsule (hollow container) by adhesive-sealing or heat-sealing the collar portion 16-2 of the main body 16 and the collar portion 17-2 of the upper lid 17 (Fig. 4 (II ), (IV)).

[Operation] As shown in FIGS. 4 to 7, after the upper and lower collar portions 16-2, 17-1 or 14-2, 15-1 are joined by sealing, the air vent holes 15-2, 17-2 are formed. Through the suction port 28, the suction pump 22 can remove minute residual air inside the capsule. At the same time, the air vent holes 15-2, 17-2
The granulated powder 3 can be completely sealed in the capsule by sealing the protrusions. The air vent holes 15-2, 17-
Since the fibrous filter is filled in the protrusions of No. 2, it is possible to prevent the granulated powder 3 from being sucked and discharged at the same time when the residual air is sucked.

[Operation] As shown in FIG. 8, a large number of the granulated powder-filled capsule bodies 36A or 36B are simultaneously CIP-pressed, so that the granulated powder 3 in the capsule bodies 36A, 36B has an intergranular adhesion force. Increase and become one. In addition, CIP
Not only the capsule bodies 36A and 36B after pressurization but also the capsule bodies 36A and 36B before CIP pressurization are both reinforced because they are covered with a shell, so that they can withstand a little rough handling conveyance. obtain. Therefore, when the capsule bodies 36A and 36B are charged into the CIP device, they can be randomly charged, and the amount of each charge can be increased, which is advantageous in improving productivity and reducing costs.

[Operation] ... Capsule body 36 after CIP
In A and 36B, the granulated powder 3 inside is integrated,
Since it is reinforced with a shell, it can withstand chucking during machining, and the finished shell can be easily removed by cutting and grinding. As a result, almost Net Shape before firing
(Nearest Net Shape) shaped green ceramics can be provided with high yield (yield of expensive ceramic raw materials, and number yield by preventing breakage and chipping).

Further, in the method of pressing the granulated powder 3 in the plastic container (capsule) through the upper mold 21 as shown in FIGS. 6 and 7, the distance from the mold contact surface in the pressing direction. The propagation load in the granulated powder 3 is drastically reduced with the increase of, and the filling rate of the granulated powder 3 tends to decrease near the center of the shaft portion.
As shown in FIG. 7B, a plastic container (main body 1
4) is finished in the shape of entasis (thick cylinder), and C
Even in the Nearest Net Shape processing after removing the capsules after IP, the shape after firing can be finished into a right circular cylinder by entasis finishing, which improves the material yield and improves the finishing polishing time of the hardened ceramic after firing. It can be shortened, which is advantageous for cost reduction.

Therefore, according to the above molding method, the following effects can be obtained.

[Effects] ... Preliminarily manufactured ultra-thin plastic containers (main bodies 14, 16 and upper lids 15, 17)
Since the granulated powder 3 is filled in and sealed in, the three-dimensional curved surface product can be molded easily and at high speed.

[Effects] For the same reason as above, since unnecessary parts such as weirs and flow paths other than the product are not formed at the time of molding, expensive ceramic raw materials can be produced at a high yield.

[Effect] In Example 1 (FIG. 4), since the granulated powder 3 was vibratingly filled in the plastic container, the granulated powder 3 was uniformly filled in all areas, and there was no deformation during firing in the subsequent process and Uniform shrinkage, density, strength, etc. can be obtained. On the other hand, in Example 2 (FIG. 6), the granulated powder 3 was vibratingly filled in the plastic container and pressed by the upper and lower molds 21 and 18,
The packing density is higher. On the other hand, since the pressing load distribution becomes non-uniform, by pre-molding the plastic container shape into a shape (for example, entasis) that considers this non-uniform load distribution, the product shape after shrinking during firing in the post process,
Uniform dimensions, density, strength, etc.

[Effect] Since the granulated powder 3 is hermetically filled in each thin and elastic plastic container, a uniform pressure is applied to the entire outer surface of the capsules 36A and 36B during CIP pressurization. Therefore, they can be simultaneously charged into the CIP device, and large-scale batch processing can be performed. Moreover, since the capsules 36A and 36B are covered with shells, the granulated powder 3 in the shells is less likely to be damaged. Contributes to improved productivity and cost reduction. In addition, since the plastic container is pre-formed in a predetermined shape in a separate line, from powder filling to sealing (Fig. 4 (II) ~
By providing each step of (V)) on a rotary table or on a straight production line, high-speed and large-volume processing including loading and unloading of ultralight plastic containers can be performed.

[Effect] ... Since the capsule bodies 36A and 36B filled and sealed with the granulated powder 3 are reinforced by the shell coating, the holding external force, the external processing force during the material handling or machining, and the space between the capsule bodies. Since it is possible to prevent breakage and chipping due to mutual collision, interference or drop, etc., the number yield is increased and the cost is reduced.

[Effect] ... The preformed plastic container has fine protrusions (eg, identification marks 15-3 and 16-3).
Since it is possible to provide a concave portion or a concave portion (eg, cotter groove 14-1), the three-dimensional molding property is improved more than ever, and the granulated powder filling property is enhanced by vibrating the fine concavo-convex portion. , The raw material yield is improved.

[Effect] Since the plastic container is preformed in a separate step, the resin film coating sealing step carried out by the molding method of the previously proposed invention (see FIG. 12) can be omitted.
Further, since the uneven portion can be formed as described in the above effect, the number of cutting or polishing steps before and after firing can be significantly reduced.

[Effect] In the method of the present invention, after the granulated powder 3 is hermetically sealed in the plastic container, hydrostatic pressure is applied by a liquid, especially water, so that the hermetic seal is insufficient and the resulting uniform density is obtained. This facilitates the selection of defective products in the event of insufficient productization. That is, the pressurized water permeates into the capsule from the defective seal part, and the water once permeated does not evaporate from the capsule even if left standing for half a month, which increases the weight. Quality can be guaranteed by installing it.

[0051]

As described above in detail with the embodiments of the invention, according to the present invention, the following effects can be obtained.

[Effect] Since the granulated powder is filled and sealed in a prefabricated ultra-thin plastic container, it can be molded easily and at high speed even for a three-dimensional curved surface product.

[Effect] For the same reason as above, since waste parts such as weirs and flow paths other than the product are not molded at the time of molding, an expensive ceramic raw material can be produced at a high yield.

[Effects] ... By vibrating and filling the granulated powder into the plastic container, it is possible to uniformly fill the entire region, so that uniform shrinkage, density, strength, etc. can be obtained without deformation during firing in the subsequent process. To be Further, when the granulated powder is filled in the plastic container, the packing density is increased by pressing with the upper and lower molds.

[Effect] Since the granulated powder is hermetically filled in a thin and elastic plastic container, C
Since a uniform pressure is applied to the entire outer surface of the capsule body at the time of pressurizing the IP, the capsules can be simultaneously charged into the CIP device and a large-scale batch processing can be performed. Further, since the granulated powder-filled capsule body is covered with the shell, the granulated powder in the shell is less likely to be damaged, so that the granulated powder can be randomly charged into the CIP device to increase the filling rate in the device and improve the productivity. It contributes to improvement and cost reduction. In addition, since the plastic container is pre-formed into a predetermined shape in a separate line in advance, by installing each process from powder filling to sealing on the rotary table or on a straight production line, loading of the super lightweight plastic container, High-speed and large-volume processing including unloading is possible.

[Effect] Since the capsule body filled and sealed with the granulated powder is reinforced by the shell coating, the holding external force and the processing external force at the time of material handling and machining, as well as mutual collision between capsule bodies, Breakage due to interference or drop,
Since chipping can be prevented, the number yield is increased and the cost is reduced.

[Effect] ... The preformed plastic container has fine projections (identification marks, etc.) and recesses (cotter grooves, etc.).
Since it is possible to improve the three-dimensional shapeability as compared with the conventional case, the granulated powder filling property is improved by vibrating the fine irregularities to improve the yield of raw materials.

[Effect] Since the plastic container is preformed in a separate step, the resin film coating sealing step carried out by the molding method of the previously proposed invention can be omitted. Further, since the uneven portion can be formed as described in the above effect, the number of cutting or polishing steps before and after firing can be significantly reduced.

[Effect] In the method of the present invention, since the granulated powder is hermetically sealed in the plastic container, hydrostatic pressure is applied by a liquid, especially water, so that the hermetic seal is insufficient and the resulting uniform density is insufficient. Facilitates the selection of defective products in the case of occurrence of. That is, the pressurized water permeates into the capsule from the defective seal part, and the water once permeated does not evaporate from the capsule even if left standing for half a month, which increases the weight. Quality can be guaranteed by installing it.

[Brief description of drawings]

FIG. 1 is an overall process diagram of manufacturing a ceramic product having a complicated shape by following a forming process according to the present invention.

2A is a cross-sectional view of a hollow plastic container (capsule) used in a ceramic molding process according to Example 1 of the present invention, and FIG. 2B is a view taken along the line AA of FIG.

3A is a cross-sectional view of a hollow plastic container (capsule) used in a ceramic molding process according to Example 2 of the present invention, and FIG. 3B is a view taken along the line BB of FIG.

FIG. 4 is a cross-sectional view showing a state in which a hollow plastic container is vibrated, filled and sealed with granulated powder in a ceramic molding process according to Example 1 of the present invention.

FIG. 5 is a cross-sectional view showing a state where the hollow plastic container has been completely filled and sealed with the granulated powder in the ceramic molding process according to Example 1 of the present invention.

FIG. 6 is a cross-sectional view showing a state when the hollow plastic container is pressed, filled, and sealed with the granulated powder in the ceramic molding process according to Example 2 of the present invention.

FIG. 7 is a cross-sectional view showing a state where filling and sealing of a plastic container with granulated powder is completed in a ceramic molding process according to an example of the present invention.

FIG. 8 is a cross-sectional view showing a state in which a hollow plastic container filled with granulated powder and hermetically sealed is subjected to a large amount of processing at one time by CIP (low temperature isostatic pressing).

FIG. 9 is a flowchart showing a typical example of a forming process in a conventional ceramic manufacturing process.

FIG. 10 is a front view showing the appearance of an engine valve as a product example having a three-dimensional curved surface.

FIG. 11 is a perspective view showing an external appearance of a turbine rotor blade as a product example having a three-dimensional curved surface.

FIG. 12 is a flowchart showing a molding process using a conventional molding method.

FIG. 13 is a cross-sectional view showing a state when the granulated powder is filled in the conventional molding method.

FIG. 14 is a cross-sectional view showing a state in which a resin is covered and sealed by a conventional molding method.

[Explanation of symbols]

 1 Engine Valve 1-1 Cotta Groove 2 Turbine Blade 2-1 Connection Part 3,3-1, 3-2 Granulated Powder 14,16 Container Main Body 14-2, 16-2, 15-1, 17-1 Collar Part 15, 17 Upper lid 15-2, 17-2 Air vent hole 18 Lower mold 19,25 Vibrator 20 Lower mold 21 Upper mold 22 Suction pump 23 Heating pressing ring 24 Vibrating bed 26 Hopper 28 Suction port 29 Seal heater 30 High-pressure container 31 Upper lid 32 Injection port 33 Air vent valve 34 Pressurized medium (normal temperature water) 35 Multi-stage arrangement jig 36A, 36B Granule powder filled capsule body

Claims (3)

[Claims] 1. A shape in which a molding allowance is preliminarily taken into consideration in a subsequent step
A step of filling a granulated powder having a preliminarily adjusted composition in an ultrathin hollow plastic container molded to size and at the same time sealing the granulated powder charging opening of the hollow plastic container under reduced pressure is performed. After that, a method for producing a ceramic member is characterized in that the plastic container is subjected to low temperature isostatic pressing to obtain a uniform density treatment, and further pre-firing shaping machining, firing, and partial polishing finish. 2. A shape that takes into account a molding allowance in a later step
In the molding step of filling the granulated powder having a composition adjusted in advance in a hollow plastic container having an elasticity and formed into a size and having a composition adjusted at the same time, the granulated powder charging opening of the hollow plastic container is sealed under reduced pressure. As a method of filling the hollow plastic container with the granulated powder, the upper part of the hollow plastic container is pressed by using an upper mold in a mold for contacting and holding the outer periphery of the hollow plastic container, and at the same time, the granulated powder charging opening of the hollow plastic container is depressurized. A method for forming a ceramic powder, which comprises sealing below. 3. A shape in which a molding allowance is preliminarily taken into consideration in a post process.
In the molding step of filling the granulated powder having a composition adjusted in advance in a hollow plastic container having an elasticity and formed into a size and having a composition adjusted at the same time, the granulated powder charging opening of the hollow plastic container is sealed under reduced pressure. As a method of filling the hollow plastic container with the granulated powder, the granulated powder is charged and filled while vibrating the hollow plastic container, and the granulated powder charging opening of the hollow plastic container is sealed under reduced pressure. A method of molding a ceramic powder, which is characterized in that: