JPS6153007A - Method of heating-molding ceramics - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for thermoforming ceramics.

(Prior art) Various ceramic products such as tableware, sanitary ware, crafts, tiles, electrical and electronic parts, etc. are produced by molding a hydrous ceramic material (slip) into a desired shape using a mold, processing,
It is made by drying and then firing. As methods for forming this slip, casting methods such as discharge casting or solid casting, and plastic forming methods using a potter's wheel are widely used.

Conventionally, in this type of molding method, a Ceracola mold is generally used as the mold, and in cast molding, slip is poured at room temperature after the mold is assembled, and υ is deposited by water absorption in the mold, and the parts that are not deposited are drained. He used a method of compacting the soil, either by draining the mud (solid discharge casting) or without draining the mud (solid casting), but by removing the mold. In addition, in plastic molding, a slip is placed on a Ceracola mold at room temperature, and the Ceracola mold is rotated and then applied with a trowel such as a roller to form the desired shape.

(Problems to be Solved by the Present Invention) However, in the bottom-shaped method as described above, ink is formed only by the natural water absorption power of the Ceracola mold, so the ink forming speed is slow, and the drying of the absorbed moisture after molding is difficult. Since it takes a long time to process, there are problems in that productivity is low and molding costs are high.

In addition, the Ceracola type is subject to severe wear and lacks mechanical strength such as compression and bending, so it tends to chip at some corners or peel off the surface in a short period of time. Therefore, it has poor durability and can only be used a few hundred times at most, and it also has problems in that it cannot be easily molded into large, complex and precise shapes due to its strength and wear and tear, and it is easily attacked by acids. Therefore, there was a problem in that it interfered with the molding of fine ceramic products.

(Means for Solving the Problems) The invention was created through repeated research to eliminate the problems of the conventional ceramic molding method as described above, and its purpose is to improve the molding efficiency ( Ceramics that can improve mold deposition speed, mold release time), shorten mold drying time, and mold various ceramic products of large size, IFI, and complex shapes at low cost and with high productivity. The objective is to provide a molding method.

In order to achieve the above object, the present invention uses a special die as a forming die, and actively utilizes the characteristics of this die to cast slip under heated conditions and perform plastic shaping or pressure forming. This is what I did.

That is, in molding ceramics, the present invention
Using an air-permeable composite firing mold in which ceramic powder is mixed and kneaded with metal powder and a binder containing components that evaporate or burn out to form a slurry, this is poured into a mold, solidified, and then fired.
Ceramics are molded while heating this breathable composite firing mold to a required temperature.

The heating method for the above-mentioned breathable composite firing mold is atmospheric heating or/
Alternatively, direct heating (conduction heating) can be used, and the heating temperature is generally 30° C. or higher, although it depends on the amount of moisture in the slip.

The molding method of the present invention is generally applied to discharge casting, cast molding represented by solid casting, and plastic molding represented by roller machine, but may also be applied to pressure molding.

(Function) The air-permeable composite firing mold according to the present invention uses at least ceramic powder and metal powder, or reinforcing fibers added thereto, as an aggregate, and a caking material containing an evaporable or burnable component that does not remain after firing. It is obtained by baking the mixture with the added agent.

This mold has a dense hardened layer with metal powder oxide dispersed on at least its surface, and the evaporated or burned-out component in the binder escapes from the surface layer during drying or firing, resulting in countless fine particles. Open pores are formed throughout the mold, which create good water absorption.

Moreover, it has high compressive strength and bending strength due to the shell effect of the hardened layer, has good heat resistance because it is fired at a high temperature, and has excellent thermal conductivity due to the combination of metal powder. Furthermore, since a hardened layer is formed by mixing and firing metal powder and ceramic powder, it has significantly higher wear resistance than Ceracola type or resin type, and will not chip or peel off at some corners even after repeated use. It also has good chemical resistance and is not easily attacked by water or acids. Also, mold shrinkage (dimensional change) is small, and this effect is particularly great when reinforcing fibers are added as aggregate.

In the present invention, a ceramic material is molded using the above-mentioned breathable composite firing mold. During this molding, the breathable composite firing mold is actively heated. Since metal powder oxide is dispersed inside and has good thermal conductivity, a sufficient amount of heat is accumulated within the mold, and this acts on the ceramic material through the mold surface. Therefore, when the ceramic material comes into contact with the mold surface, water is rapidly absorbed from the mold surface, evaporates vigorously, and is discharged out of the mold through the ventilation holes. In addition, because the wettability of water improves, the water absorption capacity of the mold itself increases significantly compared to when it is at room temperature, and a high water removal effect continues. Furthermore, since the temperature of the ceramic material itself increases due to heat conduction, water removal during mud removal during casting is also accelerated. As a result, the deposition speed is much faster than that of the conventional Ceracola type.

In addition, the moisture contained in the inking layer or molding layer quickly permeates from the center to the surface layer and is efficiently absorbed from the entire surface of the heated mold, and the moisture inside the mold also passes through the ventilation holes. It is forcibly removed by evaporation. Therefore, soil compaction is good, and even though the mold does not have an ion exchange function, good mold release properties are imparted, and mold release time is shortened.

Furthermore, even after the mold is released, heat has already been applied to the mold from the molding process, and the absorbed moisture is gradually discharged. can be used for drying, and the amount of heat required for drying can be reduced.

(Example) Embodiments of the present invention will be described below based on the accompanying drawings.

First, the invention uses a special mold called a breathable composite firing mold for molding the ceramic material.

Figures 1 to 5 illustrate the mold 1 according to the present invention. Figure 1 is for discharge casting, Figure 2 is for solid casting, Figure 3 is for plastic molding, and Figure 4 is for molding. Indicates pressure molding.

The ceramic molds shown in FIGS. 1 to 3 are made of an air-permeable composite fired body made of metal powder and ceramic powder as aggregates, and have a dense hardened layer 2 on the outer shell including at least the mold surface 11. It is formed. In this example, the hardened layer 2 reaches the center of the wall thickness, but in some cases, the hardened layer 2 does not reach the center, and a backing made of an unfired mixed structure of metal powder and ceramic powder is formed inside. It may have layers.

In FIG. 4, a mold 1 is made of a composite sintered body made of metal powder, ceramic powder, and reinforcing fibers 4 as aggregates. It goes without saying that the molds shown in FIGS. 1 to 3 may have a reinforcing fiber dispersed structure similar to that shown in FIG. 4.

Furthermore, in the case of a split type, one side may have a conventional structure.

The above-mentioned breathable composite firing mold includes a step of mixing and kneading ceramic powder and metal powder or a binder containing a component that evaporates or burns out reinforcing fibers at a predetermined mixing ratio to obtain a slurry sample; It is made by pouring a sample into a mold and shaping it into a desired mold shape, and drying the molded body and then firing it at a high temperature.

Here, as the "metal powder", ferrous metal powder, non-ferrous metal powder, mixed powder or alloy powder thereof is used depending on the type of ceramic material to be molded, molding conditions, etc.

As the iron-based metal powder, iron powder such as cast iron powder, electrolytic powder, pure iron powder, or copper powder is used. Among these, cast iron powder has the advantage of promoting pore formation by burning free carbon during firing. Cast iron powder can be made using gray cast iron, ductile cast iron, alloy cast iron, etc. Alloy cast iron has improved heat resistance and corrosion resistance.

Non-ferrous metal powders mainly include nickel powder, chromium powder,
#1 Almost all metals can be used, such as manganese powder, molybdenum powder, titanium powder, copper powder, cobalt powder, tungsten powder, etc. Each of these may be used as a single powder, a mixed powder of two or more kinds, an alloy powder, or a composite powder. If necessary, non-ferrous metal powders other than those mentioned above, such as zinc powder, tin powder, and lead powder, may also be used, but properties such as strength and heat resistance will be degraded.

Iron-based metal powders are generally inexpensive, so they are often used, but they tend to have poor chemical stability as oxides.
If even a small amount of iron-based rust components cannot be attached,
Non-ferrous metal powder should be used. By appropriately selecting the nonferrous metal powder, 91 strength is high, heat resistance and corrosion resistance are improved, and dimensional accuracy and surface quality are improved.

For example, chromium powder is suitable for pressure molding where strength is required as a ceramic mold, and when heat resistance and corrosion resistance are particularly required as a ceramic mold. , chromium powder, nickel powder,
Molybdenum powder is effective.

As a "ceramic powder", the deformation rate at high temperatures is small,
A material that can be easily bonded to metal powder is used. For example, neutral types such as mullite, calcined alumina, activated alumina, fused alumina, chromite, and sillimanite, and acidic types such as fused silica, zirconia, and fused zircon are generally suitable.

Basic materials such as magnesia and talc can also be used, but if the binder is something like silica sol, it is generally stable at a pH of 2 to 4. A neutral or acidic refractory powder would be appropriate.

Generally speaking, steel thread is suitable as a "reinforced material". In particular, stainless steel fibers do not corrode during the firing process, so they have a high reinforcing effect on both the hardened layer and the backing layer. Other reinforcing fibers, such as regular steel fibers such as free-cutting steel, ceramic fibers such as glass fibers and alumina fibers, and carbon fibers, can also have a reinforcing effect, and have the advantage of preventing cracks and preventing ceramic powder from falling off. can be obtained. For example, glass fiber can be expected to have a great reinforcing effect because it has good adhesion with binders, and is also useful in cases where iron oxide noise is extremely strong.

In addition, the particle size of the metal powder when unmolded is generally 2 to 500 μm in its maximum size. The particle size of the ceramic powder is preferably 10 to 300 μm in its maximum size. The lower limit was specified because, although from the standpoint of transferability and surface roughness of the mold surface, the finer the particle size is, the better it is, but on the other hand, cracks are more likely to occur. The reason why the upper limit is specified is because of the need for strength and because excessive porosity would deteriorate the surface properties of the mold. The particle size is appropriately selected between upper and lower limits depending on the specific ceramic molding application and usage conditions (molding shape, mold surface roughness, etc.).

In addition, the reinforcing fibers may be used depending on the size of the mold, for example, length 0.05~30-1 (diameter converted) 5~400μ.
It is sufficient to appropriately select one within the range of m. Among the reinforcing fibers, for example, stainless steel fibers and steel fibers are preferably produced directly from blocks using a self-excited vibration cutting method, but fibers produced by other manufacturing methods are not prohibited.

When reinforcing fibers are used in combination, the amount added depends on the fiber material and dimensions, but should be approximately 1 to 20VO19G.
If it is less than 1vo1%, effects such as improved strength and dimensional stability cannot be expected. However, no matter what kind of material the reinforcing fibers are made of, if the amount exceeds 20 vol %, the fiber balls will become loose and the moldability will be reduced.

In addition, excessive precipitation on the surface of the hardened layer may cause skin damage.
Moreover, it is disadvantageous in terms of cost.

In the case of metal fibers such as stainless steel with a large aspect ratio, the upper limit is generally iC10vol. In the case of glass fibers with a small aspect ratio, for example, 0.03° in thickness and 0.1° in length, it can be added up to nearly 20vol%.

Next, "a binder containing an evaporated or burned-out component" is a substance used to bond metal powder needles and ceramic particles, and to provide fine pores to the composite fired body.

Typical binders containing evaporable components include silicon compounds, especially silica sol (colloidal silica)
,・nH,O. Silica sol is a stabilized colloidal solution of silica - for example, 8s02 concentration 2
0-21%, Na, 0 concentration 0.02% or less, pH 3-4
, viscosity (20℃) 3 cp or less, specific gravity (20℃) 1.10
There are properties of ~1.16. In this case, water evaporation is the factor that creates porosity.

Particularly preferred binders in the present invention are organosilicate binders, especially alcoholic solvent-based silica sols based on ethyl silicate. Ethyl silicate is ethyl ortho silicate.
) is a stable substance with no binder properties when used alone. To obtain the binder, ethyl silicate is mixed with an alcoholic solvent and water and hydrolyzed. As the alcohol solvent, ethanol and ingropanol are mainly used. Then, an acidic substance (hydrochloric acid, phosphoric acid, oxalic acid) is added as a catalyst to promote the reaction and stabilize the silica sol.

A blending example includes 80 parts by weight of ethyl silica, 13 parts by weight of an alcoholic solvent, 6 parts by weight of water, and 1 part by weight of a catalyst. This yields a silica sol with a silica concentration of 32%.

Further, as a binder containing a component that is burnt out, room-temperature curable resins such as urethane resins, polyester resins, and epoxy resins can be used, and those obtained by reducing the viscosity by using a solvent are particularly preferred. In addition, an appropriate amount of a known material IX represented by water glass etc. may be added to the binder.

The mixing ratio of the metal powder, ceramic powder, and binder is preferably (1 to 5): (t to 5):1 by weight, and particularly recommended is 2:2:1 to 5:5:1. Ru.

The reason for setting the blending ratio in this manner is to obtain a good balance of various properties such as foreskin, water absorption, thermal conductivity to improve the effect of mold heating during ceramic molding, and surface texture. The lower limit of the blending ratio t-1: 1: 1 is defined as:
This is because this level is necessary to obtain the minimum strength t that can be used as a mold. Upper limit 'i5: 5:1
The reason for this restriction is that if there is too much aggregate relative to the binder, the covering ability of the binder will be reduced, resulting in a decrease in strength and deterioration of the stability of the mold surface.

The reason for stipulating the upper limit for metal powder is that even if the combination of ceramic powder and binder is appropriate, if the metal powder bed becomes excessive,
This is because sufficient strength cannot be obtained, the porosity becomes higher than necessary, the surface quality deteriorates, and the transferability, which is important as a ceramic mold, is impaired. The reason why the upper limit of the ceramic powder is limited is that the strength will be impaired if excessively blended. Caking agents are necessary for bonding the aggregates together and are necessary to provide air permeability. However, excessive addition makes the fired body more porous than necessary, resulting in a decrease in strength.

Table 1 below shows preferred formulation examples according to the present invention.

Next, the process moves to a molding step to obtain a desired ceramic mold shape. This step is performed by pouring and solidifying the slurry mixed sample obtained in the previous step. That is, for example, as shown in FIG. 6, 5t of the mixed sample is poured into a mold 7 in which a mold surface element 6 such as a wedge shape, a master model, or an actual ceramic product is set, and the mixed sample is left to stand for a predetermined period of time. In this pouring process, a hardening agent is added to promote solidification, and vibration is applied to promote filling.
Scratching and squeezing are also effective. By selecting the good fluidity of the mixed sample 5 and the appropriate particle size of the metal powder and ceramic powder, the shape and pattern of the mold surface element 6 can be accurately transferred. By inserting pins and pipes into the mold during this modeling, the casting holes and mold heating mechanism shown in FIGS. 2 and 4 can be obtained.

Next, in the present invention, after the shaped body obtained in the previous step is removed from the mold, it is subjected to natural drying and/or ignition drying. This is to prevent the occurrence of cracks and distortion, as well as to make the binder more porous (pore formation) by evaporating the alcohol and moisture contained in the binder. ) is appropriately selected from a range of 1 to 48 hours depending on the size of removal.

Further, in order to accelerate drying, a high temperature atmosphere, hot air, etc. can also be used. The latter (ignition drying) can be carried out by directly igniting the molded body with a torch lamp or the like and burning the evaporated components that vaporize from the molded body.

The molded body after this drying process has air permeability throughout and can be used as is for cast molding or the like. However, it has low mechanical strength and poor durability.

Therefore, in the present invention, as shown in FIG. 7, the molded body 8 that has undergone the drying process is placed in a heating furnace 9 and fired in an oxidizing atmosphere using a heat source such as a resistance heating element or a gas table. The oxidizing atmosphere may be air, or may be oxygen-enriched air in consideration of oxygen supply. Expanding firing conditions, metal powder types,
Generally, the firing temperature should be 400 to 1500°C and the firing time should be 1 hour or more, although it depends on the blending ratio, mold dimensions, and desired water absorption rate.

The reason why the lower limit of the firing temperature was set to 400°C and the lower limit of the firing time to 1 hour was that the firing was insufficient, the dense hardened layer that is a feature of the present invention was not formed, and the strength necessary for a durable type was not achieved. Because you can't get it. The reason why we set the upper limit of the firing temperature to 1500°C is that although a hardened layer is formed, the surface becomes rough and
This is because transferability is impaired and dimensional accuracy is reduced. When the metal powder is iron-based powder, the upper limit of the firing temperature is preferably about 1000°C, and most preferably 850 to 950°C. #1 has a long firing time, but the strength is improved,
This results in rough surfaces and decreased productivity.

Through this firing step in an oxidizing atmosphere, firing of the ceramic powder and oxidative sintering of the metal powder in the molded body proceed, and a hardened layer 2 is gradually generated from the surface of the molded body toward the inside. At the same time as in step (B), volatile components of the binder and burnt-out components remaining in the molded body are burned and removed, so that the formation of porosity is promoted. Upon completion of the firing process, and by attaching a cover or a box provided with a stopper if necessary, a breathable composite firing mold as shown in FIGS. 1 to 4 can be obtained.

In the air permeable firing mold according to the present invention, the mold surface 11 is composed of the hardened layer 2 as described above, and this hardened layer 2 consists of dispersed metal powder oxide grains 20 and fired ceramic grains 2 as shown in FIG.
The hardened layer 20 has fine particles (0.1 to 50 pm, average 1 to 20 μm) due to the disappearance of evaporation or burnt-out components in the binder mentioned above on the inside of the hardened layer 20. A countless number of air holes 22 are formed, and the surface texture ranges from porous and coarse to dense and smooth due to the fine air holes. The porosity is generally 5 to 60 vol%, but depending on the type and particle size of the metal powder and ceramic powder, the mixing ratio of the metal powder, ceramic powder, and binder, the vibration and squeezing conditions during pour molding, the firing conditions, etc. It can be freely adjusted by setting it as desired while taking mold strength etc. into consideration.

The mold has a compressive strength of 100 to 1000 kg/c.
Generally, the expansion coefficient is θ~1.5% and the thermal conductivity is 0.
．． 7~1.5Kcat/m-h・1? : , heat resistance 90
It has the characteristics of 0°C, Mohs' hardness of 6 to 7, and thermal spalling of 24 hours or more (heating at 800°C for 5 minutes and cooling for 5 minutes).

Next, in the present invention, for molding ceramics, the breathable composite fired m produced in the above steps is heated, and while maintaining this state, a slip is placed on it and molded into the desired shape.

The heating method for the breathable composite firing mold may be any method such as direct heating or indirect heating. Typical heating methods include placing the entire mold in an open or heating chamber as shown in Figure 8 (a) and heating the atmosphere with a heater or hot air; A method of heating (conduction heating) by inserting a heating element such as a nichrome wire or a heating fluid into the panel heating mechanism 10 installed in advance at the required part of the mold 1, as shown in Fig. 8 (c). Possible methods include arranging a heating element 12 and heating the υ mold 1 with the heating element 12, or heating the mold 1 by embedding it in a fluidized heating layer. Of course, it is also possible to use two or more of the above heating methods in combination. Which heating method to adopt may be determined depending on the type of molding method, the water content of the ceramic material, etc.

The heating temperature of the mold 1 may be appropriately set depending on the amount of moisture in the slip, the molding method, etc., but if the heating temperature is too low, the moisture removal effect, which is a feature of the present invention, will be insufficient and demolding will be difficult. Therefore, the temperature must be at least 30°C.

However, if the heating temperature is too high, too much water is removed from the slip, resulting in loss of fluidity and deterioration of quality. Therefore, for example, in the case of cast molding, it is preferable to set the temperature to about 100°C or less.

The heated state of the mold 1 is maintained from the slip charging process to the demolding process. For example, in the case of casting molding, Fig. 9 (a)
As shown in ), the mold is heated during each step of pouring, tightening, and removing the mold. The heating temperature may be constant in each step or may be changed in each step. Furthermore, the suction force may be applied to the entire mold or part of the mold before the mold 1 is completely heated.

Type I is fired at a high temperature, so it has high heat resistance, is porous as a whole, and has metal powder oxides dispersed therein.

Therefore, a sufficient amount of heat is accumulated inside the cylinder due to heating, and the water absorption capacity is significantly improved.

In this state, water is absorbed by the slip 13 being injected into the mold iris, but in the present invention, water is not simply absorbed naturally through the ventilation holes, but as described above, the amount of heat accumulated inside the mold acts synergistically. Therefore, the moisture 14 in the slip is absorbed by the mold surface 1.
As the bottom shape of the slip 1 progresses, it is rapidly sucked in through the ventilation holes, heated while passing through the mold, and evaporated vigorously, forming the slip quickly.

Particularly in the case of cast molding, which contains a large amount of moisture, not only is the evaporation of moisture from the mold accelerated, but the slip itself is also heated, which accelerates the evaporation of moisture on the side that is not in contact with the mold surface. As a result of these, the ink deposition speed (inking t) is significantly increased compared to the Ceracola type. Moreover, since the mold surface II is porous, dense, and smooth, the transferability is extremely good, and even fine uneven patterns can be molded with high precision.

The moisture 14 absorbed in the mold after mud removal is also evaporated one after another by heating, and the entire molding layer is uniformly heated by conduction heat, so that it contracts uniformly in a short time. Therefore, mold releasability is good.

Even in the mold drying process after mold release, the mold l is heated during molding in the present invention, so the temperature rise can be reduced, and since the mold has good heat resistance, high temperature drying is possible. The time required for the drying process is extremely short.

When applied to plastic molding, it becomes possible to omit the use of a drying oven or at least significantly reduce the drying process.

Furthermore, the ceramic molded part used in the invention has high mold strength due to the hardened layer 2, and also has particularly good wear resistance. Therefore, there will be no cracking, chipping, or crumbling even with repeated rapid heating and cooling, repeated mold clamping pressure, etc.
There will be no chipping of some important corners in ceramic molds. For this reason, even if the durability of the mold is not as strong, it is much more durable than existing plaster molds, resin molds, etc., and the number of moldings can be dramatically increased compared to molding with Ceracola molds. can.

A specific example of molding ceramics according to the invention will be shown.

(2) A mold having the shape shown in FIG. 1 was used. Dimensions are total height 75w1 cavity depth 601111. The bottom diameter is 35VATRLS and the opening diameter is 50VATRLS. The mold is
Mullite powder, nickel powder and ethyl silicate 1:1:
0.45, a slurry sample made by mixing and mixing these was poured and shaped, and after being ignited and dried, it was heated to 120°C under atmospheric conditions.
It was obtained by firing at 0° C. for 6 hours. The water absorption rate of the mold at room temperature is approximately 30 coefficients, and as a result of a taper wear test based on JIS A 1453, the Ceracola mold has a water absorption rate of 0.1.
1J/1100rp, while o, oiJ/11
At 00 rpm, very good abrasion resistance was exhibited.

■Using the above mold, discharge casting was performed. The slip is a ceramic slurry with a moisture content of 29%, and the casting conditions are 10%.
It was cast in minutes.

The mold was preheated prior to molding and kept heated from the pouring process to the mold release process. The heating method uses radiant atmosphere heating using an electric furnace, which maintains the heated state from pouring to mold release. The amount of ink deposited at each heating temperature of 20 to 100° C. is shown in FIG. 10 in comparison with that of the Ceracola type under the same conditions except for heating.

From FIG. 10, it can be seen that the invention can significantly improve the amount of ink deposit. In the case of the present invention, good products were obtained even after 20,000 moldings. Similar durability was obtained when a suction force of 700 mHf was applied to the mold, and the amount of inking increased by more than 10 inches. Similar results were obtained when the molds shown in Table 1 above were used.

(Effects of the invention) According to the above-described invention, moisture in the slip can be removed extremely efficiently, so that the inking speed and mold release time can be greatly improved, and the mold drying time can be shortened. This provides the excellent effect of being able to mold various ceramic materials, including fine ceramics, at low cost and efficiently.

[Brief explanation of drawings]

Figures 1 to 4 are cross-sectional views showing a mold used in the heat forming method of ceramics according to the present invention, Figure 5 is a partially enlarged view thereof, and Figures 6 and 7 are manufacturing steps of the mold. 8 (a) to e illustrate the mold heating method. 1...mold, 5...slurry sample, 11...
Surface type, 13...Slip, 14.14...Moisture.

Claims (1)

[Claims] 1. When molding ceramics, Lamic powder with metal powder and evaporation or burning Mix and knead the binder containing the ingredients. This is made into a slurry and poured into a formwork to solidify. Using an air permeable composite firing mold that is fired after drying, Heat this breathable composite firing mold to the required temperature molding ceramics while Characteristic heating molding method for ceramics. 2. The heating method for the breathable composite firing mold is conduction heating. The cell according to claim 1 which is heat Heat forming method for lamix. 3. The heating method of breathable composite firing mold is atmosphere The method according to claim 1 which is heating Heat forming method for ceramics. 4. The heating temperature of the breathable composite firing mold is approximately 30℃. Claim 1 states that the temperature is ℃ or higher. heat forming method for ceramics. 5. Molding method is casting molding, plastic molding, pressure molding Claim 1 in any of the following forms: Heat forming method for ceramics as described in Section 1.