TWI595204B - Floor fixture - Google Patents

Description

Floor clamp

The present invention relates to a bottom plate jig used for firing various ceramic parts.

For the firing of ceramic parts, ceramic jigs have been widely used. Most of them are square plates as shown in Patent Document 1. Further, a plurality of leg portions are provided at the four corners, and protrusions are provided on the upper side of the four sides to form a superposed structure.

Further, in the firing of the ceramic component, a jig having a separate structure formed by the bottom plate jig and the baking pad placed thereon is also used. The jig having such a separate structure has an advantage that it can be used for a long period of time by exchanging the pad for firing, and can be easily suppressed by using a pad for firing corresponding to the composition of the fired ceramic article. The advantage of material movement between the fixture and the ceramic article.

However, when a baking mat having almost the same size as that of the floor-shaped jig of the square is placed and fired, depending on the firing conditions, the center portion of the side of the bottom plate jig may be cracked. In particular, when the rapid cooling rate is high, the bursting is likely to occur.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2004-53147

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a bottom plate jig which can suppress the expansion of the center portion of the side even when the rapid firing is performed.

In order to solve this problem, the inventors of the present invention have reviewed the cause of the occurrence of cracking in the central portion of the bottom plate jig, and found that a large thermal stress occurs in the central portion of the side of the bottom plate jig in the cooling process, and the thermal stress is bursting. s reason. That is, in the cooling-down project of the square-shaped bottom plate jig, the temperature of the outer peripheral portion first drops, and the temperature drop in the central portion of the side is slow, which is unavoidable. In particular, in the bottom plate jig which is fired by the backing plate, the temperature difference between the peripheral portion and the center portion of the bottom plate jig becomes large due to the heat storage of the backing plate. Therefore, the outer peripheral portion is intended to be thermally contracted to the inner side, but is restrained at the center portion of the jig having a relatively high temperature, so that a large thermal stress occurs in the central portion of the side.

The present invention has been completed based on the above findings, and is a bottom plate clamp for supporting a burned material, characterized in that the outer shape thereof is a polygonal shape in which the side is curved inward, and the concave amount in the central portion of the side is 5 to 25% of the length of the side.

For example, in the second application of the patent scope, the polygon is preferably 3 to 6 angles. Further, as in the third aspect of the patent application, the inner portion of the polygon is preferably a hollow shape, and as the fourth item of the patent application, the material is preferably SiC, mullite or alumina.

In the bottom plate jig of the present invention, since the amount of recessed in the central portion of the side is 5 to 25% of the length of the side and the side is curved inward to form a polygonal shape, the corner portion is sharply outward as shown in the following embodiment. Prominent shape. Therefore, it is possible to surely maintain the polishing pad of the same size as the polygonal shape connected to the tip end portion of the corner portion.

Further, the bottom plate jig of the present invention has a shape in which a portion where the large thermal stress is likely to be cut is formed by bending the center portion of the side portion in the inner side, and the crack at the center portion of the side portion can be prevented. When the central portion of the side is curved inward, the corner portion has a shape that protrudes sharply outward. Therefore, the corner portion is easily thermally expanded outward, and large thermal stress does not occur at the corner portion.

Therefore, even if the bottom plate jig of the present invention is rapidly fired, the expansion of the center portion of the side can be suppressed. Other effects of the present invention will be described together with the embodiments.

1‧‧‧floor fixture

2‧‧‧Burning board

3‧‧‧ side

4‧‧‧ corner

5‧‧‧ hole

6‧‧‧ hollow hole

7‧‧‧ hollow hole

Fig. 1 is a plan view showing the first embodiment.

Fig. 2 is a perspective view showing the first embodiment.

Fig. 3 is an enlarged cross-sectional view taken along the line X-X of Fig. 1.

Fig. 4 is a plan view showing a second embodiment.

Fig. 5 is a plan view showing a third embodiment.

Fig. 6 is a plan view showing a fourth embodiment.

Hereinafter, embodiments of the present invention will be described. Figure 1 shows this A plan view of a first embodiment of the invention is a perspective view of the second embodiment.

In these figures, 1 is a floor clamp of the present invention, and 2 is a baking pad placed thereon. The baking pad 2 is a member that directly supports a burned material such as a ceramic capacitor placed thereon. However, the pad 2 for firing is not an essential component of the present invention, and the burned material can be directly placed directly on the bottom plate jig 1. Further, as shown in the later-described embodiment, the material of the bottom plate jig 1 of the present invention may be SiC, alumina, mullite or the like, but the SiC quality is optimal from the viewpoint of radiation and heat conduction. The thickness of the pad 2 for firing is about 1 to 3 mm, and the size thereof is, for example, a square of 300 × 300 mm.

In the bottom plate jig 1 of the present embodiment, in order to support the material for the bake sheet 2, in this embodiment, the square side 3 is bent inward, and the corner portion 4 is protruded. As shown, the tip end of the corner portion 4 extends slightly to the outside than the pad 2 for firing. The thickness is thicker than the pad 2 for firing, for example, 4 to 10 mm, so that it has strength and rigidity. With such a configuration, only the baking mat 2 is exchanged, and it is possible to use it for a long period of time. A hole 5 for positioning is formed in the corner portion 4.

The shape of the edge 3 is an arc or a curve close to an arc. The length AB of the vertical line drawn from the center point of the edge 3 to the edge is 5 to 25% of the length CD of the edge 3. In the first drawing, as the length of the side 3, the length between the points C and D at which the end portion of the baking pad 2 intersects the side is used. If the bending of the edge 3 is too shallow (if less than 5%), the edge is a straight line, so the effect of the present invention cannot be obtained. If the bending of the edge 3 is too strong (if more than 25%), the firing is performed. The support position of the side of the backing plate 2 is too close to the inner side, and there is a risk that the side of the firing pad 2 will sag. Further, if there is a corner portion on the side 3 of the bottom plate jig 1, concentrated stress is generated at this portion, and therefore it is necessary to make it a smooth curve.

In this embodiment, the hollow holes 6 and 7 are formed in the inner portion of the bottom plate jig 1 to have a hollow shape. These hollow holes 6 and 7 are designed to reduce the heat generation capacity in order to reduce the heat capacity by reducing the weight of the bottom plate jig. The shape of the hollow holes 6, 7 is also preferably a smooth curved shape in order to avoid stress concentration. However, as in the second embodiment shown in Fig. 4, the arrangement and size of the hollow holes 6 and 7 can be freely changed, or the structure having no hollow hole can be used as in the third embodiment shown in Fig. 5. .

The overall shape of the bottom plate jig 1 is preferably 3 to 6 angles. In other words, in addition to the above-described square, it may be a three-corner shape as in the fourth embodiment shown in Fig. 6. However, when the baking pad 2 is maintained in a square shape and the bottom plate jig 1 is formed in a triangular shape, the portion of the baking pad 2 that cannot be supported by the bottom plate jig 1 is increased. Therefore, the baking pad 2 is 4 In the case of the angular shape, the bottom plate jig 1 is also preferably a quadrangular shape. The overall shape of the bottom plate jig 1 may also be a pentagon or a hexagon. However, if it exceeds the hexagonal shape, it gradually approaches a circular shape, and the length of the side 3 is also shortened, and the effect of the present invention is weakened, so that it is preferably 3 to 6 angles.

The floor clamp 1 of the present embodiment configured as described above is used for placing the baking pad 2 thereon, and in the cooling process, the heat radiation in the firing furnace and the heat from the atmosphere are transmitted from the corner. The portion 4 starts to cool down, and the center portion of the bottom plate jig 1 is covered by the bake plate 2, so that slower temperature drop is unavoidable. However, since the corner portion 4 has a sharp shape, it is free to thermally expand to the outside, and large thermal stress does not occur in this portion.

Further, conventionally, the maximum thermal stress is generated in the central portion of the side 3, and the flat portion is likely to be cracked. However, since the bottom plate jig 1 of the present invention does not have a portion corresponding to the center portion of the side of the previous product, it is possible to prevent the side. 3 of the central part Burst. Further, since the quality of the center portion of the bottom plate jig 1 is also reduced by bending the side 3 inward, the heat capacity is reduced and the temperature drop rate is increased. As a result, the temperature difference between the central portion of the side 3 and the corner portion 4 is also small, and the thermal stress is also considered to be small.

As the molding method of the floor clamp 1 of the present invention, an inflow molding method or a press molding method can be employed, but it is not limited to these molding methods.

[Examples]

The embodiments of the present invention are shown below.

The substrate clamps shown in Table 1 and the base clamps of Comparative Examples 1 to 8 shown in Table 2 were prepared by various ceramic materials, and the crack resistance and the breakage ratio at the time of use were evaluated and placed. The amount of bending of the plate on the top plate for firing. The size of the bottom plate clamp is 310×310 mm and the thickness is 5 mm. Further, the pad for firing thereon was 300 x 300 mm and an alumina plate having a thickness of 2 mm. The concave ratio shown in Table 1 means that the numerical value described in paragraph 18 has a value of 0 and the side is a straight line.

In Example 1, the alumina mullite of Comparative Example 1, and the bottom plate jig of the alumina alumina of Example 2 and Comparative Example 2, alumina and cerium oxide were mixed to form a molar ratio shown in Table 1. An organic binder (methylcellulose) and water were added to form a clay, which was formed by a hydraulic press, and was produced by firing at 1500 ° C after drying.

Example 3, Comparative Example SiC quality of the oxide bonding jig plate 3, a small amount of bentonite-based CaCO ₃ and V ₂ O ₅ in the SiC powder to water in the mixture, the amorphous silica will be added The mixture of the crucible was formed by press molding, and after firing, the cristobalite was formed between the SiC particles by one-time baking, and the mixture was sintered at 1400 ° C.

In Examples 4 to 6, the Si-impregnated SiC substrate holders of Comparative Examples 4 to 7 were obtained by adding graphite powder and organic binder (methylcellulose) and water to the SiC powder to form a clay, which was pressed with oil. The bed was formed by firing in a carbon crucible together with metal Si under vacuum and impregnating Si between the SiC particles. The highest firing temperature is 1600 °C.

In Example 7, the yttrium-nitride bonded SiC substrate of Example 8 is obtained by adding Si powder to SiC powder, kneading with water, and then casting and molding using a gypsum mold to dry it. The dried molded body was produced by firing at 1450 ° C in a nitrogen atmosphere to form SiN between the SiC particles.

In the backing jig of the recrystallized SiC material of Example 8 and Comparative Example 9, a molding binder was added to the SiC powder to form a suspension, and the obtained molded body was molded to dry the obtained molded body in an inert gas. It is produced by heating to 2200 ° C to become a recrystallized SiC.

The measurement of the porosity and the specific gravity of the volume was carried out in accordance with JIS R 2205. Further, the measurement of the bending strength was carried out in accordance with JIS R 2213. The evaluation of the bursting resistance is performed by stacking the pad for firing and the workpiece (ceramic capacitor) so that the temperature level in the furnace is changed in units of 50 ° C, and the temperature in the furnace at the temperature in the furnace when it is rapidly cooled and destroyed Said. The higher the value, the better the burst resistance.

The damage ratio at the time of use was 1300 ° C, and the damage ratio at the time of use in the kiln 150 times.

The plate bending amount of the baking pad placed thereon is the plate bending amount of the baking pad in the case where a heat load of 1300 ° C and a load of 400 g are applied.

As shown in Table 1, the bottom plate jig of the embodiment of the present invention is excellent in bursting resistance, and has a small breakage ratio at the time of use, and the amount of bending of the plate for baking is also small. In the comparative example, the concave ratio of the side is out of the range of the present invention, and in the comparative example compared with the straight line, not only the bursting resistance is lowered, but also the breaking ratio at the time of use becomes large, and the concave portions are excessively large in Comparative Examples 6 and 7. In the case, not only the damage ratio at the time of use is increased, but also the amount of bending of the plate for firing is increased.

1‧‧‧floor fixture

2‧‧‧Burning board

3‧‧‧ side

4‧‧‧ corner

5‧‧‧ hole

6‧‧‧ hollow hole

7‧‧‧ hollow hole

Claims (4)

A bottom plate clamp that supports a burned object and is placed on the top surface of the fired mat, and is characterized in that the outer shape is a polygonal shape in which the side is curved inward, and the firing is performed. When the distance between the two points at which the end portion of the pad intersects the side is the length of the side, and the distance from the center of the two points to the side of the line is the amount of the concave portion at the center of the side, The amount of recess in the central portion is 5 to 25% of the length of the side. For example, the bottom plate clamp of the first application of the patent, wherein the polygon has a shape of 3 to 6 angles. The bottom plate clamp of claim 1, wherein the inner portion of the polygon has a hollow shape. For example, the bottom plate fixture of the first application of the patent is a material of any one of SiC, mullite and alumina.