Firing tool

Abstract

To suppress uneven firing in firing a large number of subjects to be fired simultaneously.SOLUTION: A firing tool 1 comprises a tray-like frame 10 and a fireproof mesh 20 arranged above the frame 10. Then, the frame 10 comprises: an outer frame 11 being an outer shape of the frame 10; a rib 12 which crosslinks the outer frame 11; a plurality of gas passing holes 13 surrounded by the outer frame 11 and the rib 12; and a first projection 14 projecting upward from the rib 12. Then, a plurality of the fireproof meshes 20 are arranged so as to cover each of the plurality of gas passing holes 13. Then, the first projection 14 is projected upward from a top face 20a of the fireproof mesh 20 from gaps S1 to S4 of the two adjacent fireproof meshes 20. According to such a constitution, a subject to be fired is prevented from being mounted on an area above the rib 12, and uneven firing in firing a large number of subjects to be fired simultaneously can be suppressed.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The technology disclosed herein relates to a firing jig. [Background technology]

[0002] In recent years, electronic components such as multilayer ceramic capacitors (MLCCs) have been miniaturized to the order of 0.1 mm. 2 ~1000cm 2 The small electronic components are placed on the top surface of a tray-shaped firing jig about the same size and fired. In firing these small electronic components, first, a large number of firing targets (electronic components before firing) are placed on the top surface of the firing jig. Then, the piled-up firing targets are leveled and made flat. This results in hundreds to tens of thousands of firing targets being distributed on the top surface of the firing jig. The firing jig is then placed inside a firing furnace and fired. This allows a large number of electronic components to be produced simultaneously.

[0003] This firing jig for electronic component production includes, for example, a frame with gas passage holes and a refractory mesh placed above the frame. In a firing jig with such a configuration, a large number of firing objects are distributed on the upper surface of the refractory mesh. When this firing jig is used, high-temperature gas during firing passes through the gas passage holes and the refractory mesh, allowing the firing objects on the refractory mesh to be efficiently heated. An example of such a firing jig is disclosed in Patent Document 1. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-48950 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when a large number of firing objects are fired simultaneously using the firing jig described above, uneven firing can occur, resulting in some of the objects being poorly fired. In this case, re-firing or sorting of defective products is required, which can significantly reduce manufacturing efficiency. The technology disclosed herein has been made to solve the above-mentioned problem, and aims to provide a technology that can suppress uneven firing when a large number of firing objects are fired simultaneously. [Means for solving the problem]

[0006] The inventors conducted extensive experiments and studies into the causes of uneven firing among multiple firing targets, and as a result, have discovered the following. In the firing jig with the above-described configuration, multiple firing targets are placed on top of a single piece of refractory mesh, which places a large weight on the thin refractory mesh. Furthermore, the firing jig is exposed to a high-temperature environment during use, which tends to reduce its rigidity. These factors can lead to the refractory mesh sinking during firing. For this reason, the frame of a typical firing jig is formed with beam-like members (ribs) that support the refractory mesh from below. However, the ribs block the flow of high-temperature gas in the area above the ribs. Furthermore, because heat is likely to accumulate in the ribs, the firing targets placed above the ribs are slow to cool. As a result, differences in heating efficiency occur between the area above the ribs and other areas. Furthermore, in mass production, where hundreds or more firing targets are fired simultaneously, it is difficult to distribute the firing targets to avoid the area above the ribs. For this reason, when a large number of objects are simultaneously fired using a conventional firing jig, uneven firing is likely to occur in the resulting fired product.

[0007] The firing jig disclosed herein was developed based on the above findings. This firing jig includes a tray-shaped frame and a refractory mesh arranged above the frame. The frame of this firing jig includes an outer frame that defines the frame's exterior, ribs bridging the outer frame, multiple gas passage holes surrounded by the outer frame and the ribs, and first protrusions protruding upward from the ribs. In the firing jig disclosed herein, multiple pieces of refractory mesh are arranged above the frame so as to cover each of the multiple gas passage holes. The first protrusions protrude above the top surface of the refractory mesh from between two adjacent pieces of refractory mesh.

[0008] In the firing jig having the above configuration, the first protrusions on the ribs protrude above the upper surface of the refractory mesh. This prevents the firing objects from being placed in the area above the ribs when multiple firing objects are distributed on the refractory mesh. As a result, most of the firing objects can be fired in the area above the gas passage holes, thereby preventing uneven firing when multiple firing objects are fired simultaneously. Furthermore, in the firing jig having the above configuration, the refractory mesh placed on the frame is divided into multiple pieces. This prevents multiple firing objects from being placed in the center of a single piece of refractory mesh, thereby preventing deformation of the refractory mesh. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a firing jig according to a first embodiment. [Figure 2] FIG. 2 is a plan view of the firing jig according to the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. [Figure 4] FIG. 4 is a side view of the firing jig according to the first embodiment. [Figure 5] FIG. 5 is a plan view of the frame of the firing jig shown in FIG. [Figure 6] FIG. 6 is a side view of a laminate obtained by stacking the firing jigs shown in FIG. [Figure 7]FIG. 7 is a plan view of a firing jig according to the second embodiment. [Figure 8] FIG. 8 is a plan view of a firing jig according to the third embodiment. [Figure 9] FIG. 9 is a cross-sectional view taken along the line IX-IX in FIG. [Figure 10] FIG. 10 is a cross-sectional view of a firing jig according to the fourth embodiment. [Figure 11] FIG. 11 is a plan view of a firing jig according to the fifth embodiment. [Figure 12] FIG. 12 is a plan view of a firing jig for comparison. DETAILED DESCRIPTION OF THE INVENTION

[0010] Preferred embodiments of the technology disclosed herein are described below. Matters necessary for implementation other than those specifically mentioned in this specification (e.g., the manufacturing method of the firing jig and the firing conditions for the fired object) can be understood based on the technical content taught by this specification and the general technical common sense of a person skilled in the art. In other words, the technology disclosed herein can be implemented based on the matters disclosed in this specification and the general technical common sense of this field. In this specification, the expression "A to B" indicating a range means A or more and B or less.

[0011] First Embodiment A first embodiment of the firing jig disclosed herein will be described below with reference to FIGS. 1 to 6. FIG. 1 is a perspective view of the firing jig according to the first embodiment. FIG. 2 is a plan view of the firing jig according to the first embodiment. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. FIG. 4 is a side view of the firing jig according to the first embodiment. FIG. 5 is a plan view of the frame of the firing jig shown in FIG. 2. FIG. 6 is a side view of a stack of firing jigs shown in FIG. 4. In the drawings, the symbols X, Y, and Z represent the width, depth, and height directions, respectively. Furthermore, the symbols L, R, F, Rr, U, and D represent the left, right, front, rear, top, and bottom, respectively.

[0012] As shown in FIGS. 1 to 4, the firing jig 1 according to this embodiment includes a tray-shaped frame 10 and a refractory mesh 20 disposed above the frame 10. As will be described in detail later, the firing jig 1 according to this embodiment includes multiple pieces of refractory mesh 20A to 20D (four pieces in FIGS. 1 to 4). In a firing process for electronic components using this firing jig 1, first, a large number of firing targets (electronic components before firing) are placed on the upper surface 20a of each refractory mesh 20. The piled-up firing targets are then smoothed and flattened. As a result, a total of several hundred to several tens of thousands of firing targets are dispersed and disposed on the upper surface 20a of the refractory mesh 20. The firing jig 1 is then placed in a firing furnace and fired. This allows a large number of electronic components to be produced simultaneously. The specific configuration of the firing jig 1 will be described below.

[0013] (1) Frame As described above, the frame 10 is a tray-shaped frame. The material of the frame 10 may be any conventionally known refractory material, as long as it has sufficient fire resistance to withstand the firing process. Examples of such refractory materials include ceramic materials (typically refractory materials specified in JIS R2001) such as alumina (Al2O3), silica (SiO2), zirconia (ZrO2), magnesia (MgO), calcia (CaO), silicon carbide (SiC), and mullite (3Al2O3·2SiO2). The frame 10 may also be made of metal or alloy materials whose melting points are higher than the firing temperature. Examples of such metal materials include nickel (Ni), titanium (Ti), tungsten (W), and molybdenum (Mo). The alloy material may be an alloy containing any of the above metals.

[0014] The frame 10 according to this embodiment includes an outer frame 11, ribs 12, gas passage holes 13, and first projections 14. The frame 10 also includes second projections 15 and support columns 16. The detailed structure of the frame 10 will be described below with reference to FIG. 5.

[0015] (1-1) Outer frame The outer frame 11 is a part that forms the outer shape of the frame 10. The outer frame 11 shown in FIG. 5 is a frame body that has a rectangular planar shape. This rectangular outer frame 11 is formed by interconnecting four frame bodies, namely, a first frame body 11a to a fourth frame body 11d. Specifically, the first frame body 11a extending along the depth direction Y is formed on the left side L in FIG. 5. Meanwhile, the second frame body 11b extending along the depth direction Y to face the first frame body 11a is formed on the right side R. Furthermore, the third frame body 11c extending along the width direction X is formed on the front side F in FIG. 5. Meanwhile, the fourth frame body 11d extending along the width direction X to face the third frame body 11c is formed on the rear side Rr. The front end F of the first frame body 11a is connected to the left end L of the third frame body 11c. Meanwhile, the rear Rr end of the first frame 11a is connected to the left L end of the fourth frame 11d. The front F end of the second frame 11b is connected to the right R end of the third frame 11c. Meanwhile, the rear Rr end of the second frame 11b is connected to the right R end of the fourth frame 11d. This forms a rectangular outer frame 11 in plan view. However, the planar shape of the outer frame is not limited to the rectangle shown in FIG. 5. For example, the firing jig disclosed herein can also employ a polygonal outer frame or annular outer frame.

[0016] The thickness t1 of the outer frame 11 is preferably 1 mm or more, more preferably 2.5 mm or more, even more preferably 5 mm or more, and particularly preferably 7.5 mm or more. This ensures sufficient strength of the frame 10. On the other hand, as the thickness t1 of the outer frame 11 increases, the area of ​​the gas passage holes 13 in a plan view becomes smaller, which tends to reduce firing efficiency. Furthermore, as the thickness t1 of the outer frame 11 increases, the heat capacity of the outer frame 11 increases, making it difficult to cool the firing target. From these perspectives, the thickness of the outer frame 11 is preferably 20 mm or less, more preferably 17.5 mm or less, even more preferably 15 mm or less, and particularly preferably 12.5 mm or less.

[0017] (1-2) Ribs The ribs 12 are members that bridge the outer frame 11. Specifically, the ribs 12 are beam-shaped members that connect the first to fourth frame bodies 11a to 11d, which are opposed to each other with a predetermined gap between them. For example, the frame 10 shown in FIG. 5 includes a first rib 12a and a second rib 12b. The first rib 12a extends in the width direction X to bridge the first frame body 11a and the second frame body 11b. The second rib 12b extends in the depth direction Y to bridge the third frame body 11c and the fourth frame body 11d. The first rib 12a and the second rib 12b intersect at the center of the frame 10. In the following description, the portion where the first rib 12a and the second rib 12b intersect is referred to as an "intersection area CA."

[0018] As shown in Figs. 1 to 3, the ribs 12 in this embodiment support the refractory mesh 20 from below D. As will be described in detail later, in the firing jig 1 according to this embodiment, the refractory mesh 20 placed on the frame 10 is divided into multiple pieces. Each of the multiple refractory meshes 20 is supported by the outer frame 11 of the frame 10 and the ribs 12. This makes it possible to prevent deformation of the refractory mesh 20 due to the weight of the object to be fired.

[0019] The thickness t2 of the rib 12 is preferably 1 mm or more, more preferably 2.5 mm or more, even more preferably 5 mm or more, and particularly preferably 7.5 mm or more. This ensures a sufficient area for the rib 12, thereby more preferably preventing deformation of the refractory mesh 20. On the other hand, the thickness of the rib 12 is preferably 20 mm or less, more preferably 17.5 mm or less, even more preferably 15 mm or less, and particularly preferably 12.5 mm or less. This ensures a sufficient area for the gas passage holes 13 in a plan view, thereby improving firing efficiency.

[0020] As described above, the frame 10 shown in FIG. 5 is provided with first ribs 12a and second ribs 12b. However, the number of ribs does not limit the technology disclosed herein. The number of ribs can be increased or decreased as appropriate, taking into consideration the relationship between suppression of deformation of the refractory mesh and firing efficiency. Specifically, increasing the number of ribs makes it easier to suppress deformation of the refractory mesh, but reduces firing efficiency due to a decrease in the area of ​​the gas passage holes. On the other hand, decreasing the number of ribs improves firing efficiency, but makes it easier for deformation of the refractory mesh to occur. From this perspective, the number of ribs formed on the frame is preferably 1 to 10 (more preferably 1 to 6, and particularly preferably 1 to 4).

[0021] (1-3) Gas passage hole The gas passage hole 13 is an opening surrounded by the outer frame 11 and the ribs 12. The frame 10 according to this embodiment has a plurality of these gas passage holes 13. As shown in FIG. 3, the gas passage holes 13 penetrate the frame 10. In the firing jig 1 according to this embodiment, as shown in FIG. 3, high-temperature gas G flows in the height direction Z through the gas passage holes 13 and the refractory mesh 20. Some firing objects generate gases due to evaporation of moisture or organic components during firing. Providing the passage holes 13 and the refractory mesh 20 in the firing jig 1 makes it easy to exhaust such gases during firing. This allows the firing object placed on the upper surface 20a of the refractory mesh 20 to be heated efficiently.

[0022] In this embodiment, four gas passage holes 13 having a rectangular planar shape are formed (see FIGS. 2 and 5). Specifically, a first gas passage hole 13a is formed in the upper left (left L and rear Rr) of the frame 10 shown in FIG. 5. This first gas passage hole 13a is an opening surrounded by the first frame body 11a, the fourth frame body 11d, the first rib 12a, and the second rib 12b. Furthermore, a second gas passage hole 13b is formed in the upper right (right R and rear Rr) of FIG. 5. This second gas passage hole 13b is an opening surrounded by the second frame body 11b, the fourth frame body 11d, the first rib 12a, and the second rib 12b. Next, a third gas passage hole 13c is formed in the lower left (left L and front F) of FIG. 5. The third gas passage hole 13c is an opening surrounded by the first frame 11a, the third frame 11c, the first rib 12a, and the second rib 12b. A fourth gas passage hole 13d is formed in the lower right (right R and forward F) in Fig. 5. The fourth gas passage hole 13d is an opening surrounded by the second frame 11b, the third frame 11c, the first rib 12a, and the second rib 12b.

[0023] The total area of ​​the gas passage holes 13 (the total area of ​​the first gas passage hole 13a to the fourth gas passage hole 13d) is 50 cm 2 More than 75cm is preferable. 2 More than 100cm is preferable. 2 More than 125cm is more preferable. 2 The above is particularly preferable. This ensures a sufficient flow path for high-temperature gas, further improving the firing efficiency. On the other hand, the total area of ​​the gas passage holes 13 is 800 cm 2 Less than 775cm is preferable. 2 Less than 750cm is preferable. 2 Less than 725cm is more preferable. 2 The following is particularly preferable, which can ensure sufficient strength of the frame 10. The areas of the first gas passage hole 13a to the fourth gas passage hole 13d may be the same or different.

[0024] (1-4) 1st protrusion 1 and 3, the frame 10 in this embodiment is provided with first protrusions 14 that protrude upward U from the ribs 12. These first protrusions 14 prevent objects to be baked from being placed above the area above the ribs 12. This prevents uneven baking when multiple objects to be baked are baked simultaneously. The detailed function of these first protrusions 14 will be described later.

[0025] In this embodiment, the first protrusions 14 are wall-like protrusions that extend continuously along the extension direction of the ribs 12 (see FIGS. 1, 2, and 5). Specifically, the first protrusions 14 extending along the width direction X are formed on the first ribs 12a that extend in the width direction X. Furthermore, the first protrusions 14 extending along the depth direction Y are formed on the second ribs 12b that extend in the depth direction Y. These wall-like first protrusions 14 can more effectively prevent the baking object from being placed on the area above the ribs 12.

[0026] The thickness t3 of the primary projections 14 (see FIG. 5) is preferably 50% or more of the thickness t2 of the rib 12 described above, more preferably 55% or more, even more preferably 60% or more, and particularly preferably 65% ​​or more. This makes it possible to suitably prevent the object to be fired from being placed on the area above the rib 12. On the other hand, if the primary projections 14 are too thick, it becomes difficult to place the refractory mesh 20 above the rib 12. From this perspective, the thickness t3 of the primary projections 14 is preferably 90% or less of the thickness t2 of the rib 12, more preferably 85% or less, even more preferably 80% or less, and particularly preferably 75% or less.

[0027] In this embodiment, the first protrusions 14 are formed in portions where a plurality of ribs 12 intersect (intersection regions CA in FIG. 2). In other words, in this embodiment, the first protrusions 14 extending in the width direction X and the first protrusions 14 extending in the depth direction Y intersect in the intersection regions CA. This prevents an object to be fired from being placed on the ribs 12 in the intersection regions CA. As will be described in detail later, in this embodiment, a plurality of refractory meshes 20 are used, so that the refractory meshes 20 can be easily arranged on the frame 10 even if the first protrusions 14 are formed in the intersection regions CA.

[0028] As shown in FIGS. 1 and 3 , the first protrusions 14 are tapered, narrowing toward the upper end. This more effectively prevents firing defects. Specifically, when the firing objects are supplied to the upper surface 20a of the refractory mesh 20, several hundred firing objects are dropped from the upper U of the firing jig 1. If some of the firing objects land on the first protrusions 14, firing defects are more likely to occur. In response to this, tapering the first protrusions 14 can prevent the firing objects from landing on the first protrusions 14. Furthermore, when the firing objects falling from the upper U come into contact with the side surfaces of the tapered first protrusions 14, the firing objects are reflected toward the area above the gas passage holes 13. Therefore, the tapered first protrusions 14 also contribute to preventing the firing objects from being placed in the area above the ribs 12.

[0029] (1-5)Second protrusion Next, the firing jig 1 according to this embodiment is equipped with second protrusions 15 in addition to the first protrusions 14 configured as described above. These second protrusions 15 protrude upward U from the outer frame 11 of the frame 10. The second protrusions 15 can prevent the firing object from being placed above U on the outer frame 11. This can more effectively suppress the occurrence of firing unevenness. The second protrusions 15 can also prevent the firing object from falling from the upper surface 20a of the refractory mesh 20 while the firing jig 1 is being transported, for example.

[0030] Specifically, the second protrusions 15 are wall-like protrusions that extend continuously along the extension direction of the outer frame 11. For example, the first frame body 11a and the second frame body 11b extend along the depth direction Y. Second protrusions 15 extending along the depth direction Y are formed on the first frame body 11a and the second frame body 11b. Furthermore, the third frame body 11c and the fourth frame body 11d extend along the width direction X. Second protrusions 15 extending along the width direction X are formed on the third frame body 11c and the fourth frame body 11d. In this embodiment, the outer peripheral edge of the firing jig 1 is surrounded by these wall-like second protrusions 15. This makes it possible to prevent the firing target from being placed in the region above U of the outer frame 11 and also prevents the firing target from falling from above the firing jig 1.

[0031] Furthermore, it is preferable that the second protrusions 15 have the same configuration as the first protrusions 14. For example, it is preferable that the second protrusions 15 are tapered protrusions that become thinner toward the upper end. This can more effectively prevent the occurrence of firing defects. Furthermore, the second protrusions 15 may be formed at the intersection of the outer frame 11 and the rib 12. For example, the first frame 11a shown in FIG. 2 has two second protrusions 15 formed thereon, extending in the extension direction (depth direction Y) of the first frame 11a. However, it is also possible that one second protrusion 15 extends in the depth direction Y over the entire area of ​​the first frame 11a. Even when such a configuration is adopted, it is possible to prevent the occurrence of firing defects.

[0032] The thickness t4 of the second projections 15 (see FIG. 5) is preferably 50% or more of the thickness t1 of the outer frame 11, more preferably 55% or more, even more preferably 60% or more, and particularly preferably 65% ​​or more. This more preferably prevents the object to be fired from being placed in the region U above the outer frame 11. On the other hand, if the second projections 15 are too thick compared to the outer frame 11, it becomes difficult to place the refractory mesh 20 on the outer frame 11. From this perspective, the thickness t4 of the second projections 15 is preferably 90% or less of the thickness t1 of the outer frame 11, more preferably 85% or less, even more preferably 80% or less, and particularly preferably 75% or less.

[0033] (1-6) Support Furthermore, the frame 10 in this embodiment is provided with four support columns 16 that protrude upward U from the outer frame 11 (see FIGS. 1, 2, and 5). As shown in FIG. 6, firing jigs 1 equipped with the support columns 16 can be easily stacked along the height direction Z. This further improves the manufacturing efficiency of electronic components per unit area. Note that the height of the support columns 16 is preferably greater than the height of the first projections 14. This allows a gap S through which high-temperature gas can flow to be generated between the upper firing jig 1 and the lower firing jig 1. As a result, a decrease in firing efficiency in the lower firing jig 1 can be suppressed.

[0034] The support pillars need only have a configuration that allows multiple firing jigs to be stacked, and are not limited to the configuration shown in Figures 1, 2, and 5. For example, in the firing jig 1 shown in Figures 1, 2, and 5, four support pillars 16 protrude upward U from the outer frame 11. However, the support pillars may protrude from the ribs instead of the outer frame. Even in this case, multiple firing jigs can be stacked. Furthermore, the number of support pillars is not limited to four. As long as the number of support pillars is three or more, multiple firing jigs can be stacked. However, considering stability during stacking, the number of support pillars is preferably four or more.

[0035] (2) Fireproof mesh Next, the refractory mesh 20 is placed above the frame 10. This refractory mesh 20 is a plate-shaped porous body. This allows high-temperature gas to pass through during firing. The object to be fired is distributed over the upper surface 20a of this refractory mesh 20. Then, the high-temperature gas during firing passes through the gas passage holes 13 of the frame 10 and the refractory mesh 20, and is supplied to the object to be fired on the refractory mesh 20. This allows the object to be fired to be heated efficiently.

[0036] The material of the refractory mesh 20 need only have sufficient fire resistance to withstand the firing process. For example, the refractory mesh 20 can be made of metal materials such as nickel (Ni), titanium (Ti), tungsten (W), and molybdenum (Mo). Alloys containing these metals can also be used. These metal materials (or alloy materials) have excellent fire resistance and high thermal conductivity, allowing the object to be fired on the refractory mesh 20 to be heated more efficiently. The refractory mesh 20 can also be made of ceramics (typically refractory materials specified in JIS R2001), such as alumina (Al2O3), silica (SiO2), zirconia (ZrO2), magnesia (MgO), calcia (CaO), silicon carbide (SiC), and mullite (3Al2O3·2SiO2). Considering the balance between heat resistance and thermal conductivity, a nickel refractory mesh 20 is particularly preferred. The refractory mesh 20 may be modified depending on the composition of the object to be fired. For example, when the object to be fired contains a conductive paste made of Ni, it is more preferable to use a refractory mesh 20 made of nickel, which can prevent impurities from the refractory mesh 20 from being mixed into the object to be fired.

[0037] Furthermore, it is preferable to appropriately adjust the average pore diameter of the refractory mesh 20 depending on the size of the object to be fired. For example, in recent years, small electronic components on the order of 0.1 mm have been developed. In response to this, the average pore diameter of the refractory mesh 20 is preferably 500 μm or less, more preferably 200 μm or less, and particularly preferably 100 μm or less. In this case, the lower limit of the average pore diameter of the refractory mesh 20 is preferably 25 μm or more, more preferably 50 μm or less, and particularly preferably 75 μm or less. This improves the gas permeability of the refractory mesh 20, thereby further improving heating efficiency. However, the average pore diameter of the refractory mesh 20 is not limited to the above-mentioned numerical range. For example, when firing large electronic components on the order of 1 mm, the average pore diameter of the refractory mesh 20 can be set to 200 μm or more (preferably 500 μm or more, more preferably 1000 μm or more).

[0038] Here, the firing jig 1 according to this embodiment uses a plurality of refractory meshes 20A to 20D. The plurality of refractory meshes 20A to 20D are arranged above the frame 10 so as to cover the plurality of gas passage holes 13a to 13d, respectively. Specifically, the first gas passage hole 13a at the upper left of the frame 10 is covered by the first refractory mesh 20A. The second gas passage hole 13b at the upper right of the frame 10 is covered by the second refractory mesh 20B. The third gas passage hole 13c at the lower left of the frame 10 is covered by the third refractory mesh 20C. Furthermore, the fourth gas passage hole 13d at the lower right of the frame 10 is covered by the third refractory mesh 20C. This allows objects to be fired to be placed above the first gas passage hole 13a to the fourth gas passage hole 13d, respectively.

[0039] The first protrusions 14 of the frame 10 protrude upward from the gaps S1 to S4 between two adjacent refractory meshes 20, above the upper surfaces 20a of the refractory meshes 20 (see FIG. 3). Specifically, a gap S1 extending in the depth direction Y is formed between the first refractory mesh 20A and the second refractory mesh 20B. A gap S2 extending in the width direction X is formed between the second refractory mesh 20B and the fourth refractory mesh 20D. A gap S3 extending in the depth direction Y is also formed between the fourth refractory mesh 20D and the third refractory mesh 20C. A gap S4 extending in the width direction X is also formed between the third refractory mesh 20C and the first refractory mesh 20A. The first protrusions 14 of the frame 10 protrude upward from the upper surfaces 20a of the refractory meshes 20 through these gaps S1 to S4 (see FIG. 3).

[0040] (3) Effects of the First Embodiment As described above, the firing jig 1 according to this embodiment has the first protrusions 14 that protrude upward from the ribs 12 in the upward direction U. The first protrusions 14 protrude upward from the gaps S1 to S4 between two adjacent pieces of refractory mesh 20 beyond the upper surface 20a of the refractory mesh 20 in the upward direction U. This makes it possible to suppress firing unevenness when firing multiple firing objects simultaneously. This will be specifically described below in comparison with the prior art.

[0041] FIG. 12 is a plan view of a comparative firing jig. The firing jig 100 shown in FIG. 12 includes a tray-shaped frame 110 and a refractory mesh 120 disposed above the frame 110. The firing jig 100 shown in FIG. 12 also includes ribs 114 bridging the outer frame 112 of the frame 110. In a firing process using this firing jig 100, multiple firing targets are distributed over the upper surface of the refractory mesh 120. Since the refractory mesh 120 is supported by the ribs 114, deformation of the refractory mesh 120 due to the weight of the firing targets can be prevented. However, in the support area SA above the ribs 12 of the firing jig 100 configured as described above, the ribs 114 block the flow of high-temperature gas in the height direction (the direction perpendicular to the plane of FIG. 12 ). Furthermore, in this support area SA, gas generated from the firing targets is less likely to be exhausted. Furthermore, the baking object placed on the support area SA is slow to cool because heat is likely to accumulate on the ribs 144. As a result, baking unevenness is likely to occur between the gas passage holes 116 and the ribs 12.

[0042] On the other hand, as shown in FIGS. 1 to 3, in the firing jig 1 according to this embodiment, first protrusions 14 protrude from the ribs 12. The first protrusions 14 protrude above the upper surface 20a of the fireproof mesh 20 through the gaps S1 to S4 between the multiple fireproof meshes 20. Therefore, when a large number of firing objects are distributed on the upper surface 20a of the fireproof mesh 20, the firing objects are less likely to be placed in the area above the ribs 12. As a result, most of the firing objects can be heated above the gas passage holes 13. As a result, the various problems described above can be solved, and uneven firing can be suppressed when a large number of firing objects are fired simultaneously.

[0043] Furthermore, in the firing jig 1 according to this embodiment, second protrusions 15 protrude from the outer frame 11. These second protrusions 15 also protrude upward U from the upper surface 20a of the refractory mesh 20. This prevents the firing objects from being placed on the outer frame 11. As a result, the number of firing objects heated above the gas passage holes 13 further increases, making it possible to further uniform the heating efficiency for the multiple firing objects.

[0044] Furthermore, in the firing jig 1 according to this embodiment, each of the plurality of refractory meshes 20A to 20D is arranged in an area surrounded by the first protrusions 12 and the second protrusions 15. This restricts each of the plurality of refractory meshes 20A to 20D from moving in the planar direction (the width direction X and the depth direction Y). This prevents the refractory mesh 20 from falling off the frame 10.

[0045] The first embodiment of the firing jig disclosed herein has been described above. However, the technology disclosed herein is not limited to the above-described embodiment. Other embodiments of the technology disclosed herein will be described below.

[0046] <Second embodiment> FIG. 7 is a plan view of a firing jig according to a second embodiment. In the first embodiment described above, the second protrusions 15 protruded from the outer frame 11 of the frame 10 (see FIGS. 1 to 3). However, the second protrusions are not an essential component of the firing jig disclosed herein. Specifically, in the firing jig 1A according to the second embodiment, only the first protrusions 14 are formed on the ribs 12, and no protrusions are formed on the outer frame 11 (see FIG. 7). Even with this configuration, firing unevenness can be sufficiently suppressed when multiple firing objects are fired simultaneously. Specifically, in a typical firing process, the firing objects are placed around the center of the firing jig to prevent them from falling off the firing jig. Therefore, when using a typical firing jig, the firing objects are rarely placed on the outer peripheral edge of the refractory mesh 20 (i.e., above the outer frame 11). Therefore, poor firing due to the interruption of high-temperature gas is most likely to occur in the area above the rib 12 located in the center of the firing jig 1A. For this reason, forming the first protrusions 14 on the rib 12 can sufficiently suppress the occurrence of uneven firing.

[0047] Furthermore, in the firing jig 1 according to the first embodiment, the support pillars 16 protruding upward U from the frame 10 are formed (see FIGS. 1 to 3). However, these support pillars are not an essential component of the firing jig disclosed herein. Specifically, in the firing jig 1A shown in FIG. 7, no support pillars are formed on the frame 10. However, in the firing jig 1A shown in FIG. 7, other firing jigs can be stacked on top of the first projections 14. Even when such a configuration is adopted, the firing efficiency per unit area can be improved.

[0048] <Third embodiment> FIG. 8 is a plan view of a firing jig according to a third embodiment. FIG. 9 is a cross-sectional view taken along the line IX-IX in FIG. 8. As described above, in the first embodiment, the second protrusions 15 are formed on the outer frame 11 to prevent firing defects in the region above the outer frame 11 (see FIGS. 1 to 3). However, firing defects in the region above the outer frame 11 can also be prevented by a configuration other than the second protrusions 15. For example, as shown in FIG. 8, in a firing jig 1B according to the third embodiment, a damming portion 24 that is higher than the height of the central portion 20c of each of the plurality of refractory meshes 20A to 20D is provided on the outer peripheral edge portion 20b. As shown in FIG. 9, the damming portion 24 is formed by folding over the outer peripheral edge portion 20b of each of the refractory meshes 20A to 20D. The blocking portion 24 having such a configuration can prevent the object to be fired from moving outside each of the refractory meshes 20A to 20D. This prevents the object to be fired from being placed in the area on the outer frame 11, thereby preventing poor firing in the area on the outer frame 11 without providing a second protrusion. Furthermore, forming a blocking portion 24 on each of the multiple refractory meshes 20A to 20D can also prevent the object to be fired from moving toward the center of the firing jig 1B, thereby more effectively preventing the object to be fired from being placed on the ribs 12. Note that blocking portions do not need to be formed on all of the multiple refractory meshes.

[0049] <Fourth embodiment> FIG. 10 is a cross-sectional view of a firing jig according to a fourth embodiment. In the firing jig 1C shown in FIG. 10, the damming portion 24 is formed by bending the outer peripheral edge portion 20b of the refractory meshes 20A to 20D upward in a U direction. The damming portion 24 having such a configuration can also prevent the firing target from being placed in the area above the outer frame 11, thereby suppressing firing defects in that area. The damming portion 24 in this embodiment, in which the refractory mesh 20 is bent upward in a U direction, can easily ensure the height of the damming portion 24, thereby more effectively suppressing firing defects in the area above the outer frame 11. However, considering the strength of the damming portion 24, it is preferable to form the damming portion 24 by folding the refractory mesh 20 over as shown in FIG. 9.

[0050] <Fifth embodiment> FIG. 11 is a plan view of a firing jig according to a fifth embodiment. In the first embodiment, four gas passage holes 13 were formed in the frame 10 (see FIGS. 2 and 5). However, the number of gas passage holes does not limit the technology disclosed herein. For example, in the fifth embodiment shown in FIG. 5, nine gas passage holes 13 are formed in the frame 10. The technology disclosed herein can easily accommodate changes in the number of gas passage holes because the number of refractory meshes 20 can be increased or decreased depending on the number of gas passage holes. Furthermore, as shown in FIG. 11, depending on the number of gas passage holes 13, the refractory mesh 20 may be disposed in an area surrounded only by the first protrusions 14. The refractory mesh 20 surrounded only by the first protrusions 14 is also restricted from moving in the planar direction, which effectively prevents the refractory mesh 20 from falling off the frame 10.

[0051] <Other embodiments> Although not shown in the drawings, the firing jig disclosed herein may adopt configurations other than those of the first to fourth embodiments described above. For example, the first protrusions 14 in the first to fourth embodiments are wall-like protrusions that extend continuously along the extension direction of the ribs 12. However, the first protrusions are not limited to wall-like protrusions. For example, columnar first protrusions may be scattered along the extension direction of the ribs. Even when such a configuration is adopted, it is possible to sufficiently prevent the firing object from being placed on the ribs.

[0052] Specifically, when the total area of ​​the rib upper surface is taken as 100%, the area of ​​the region where the primary projections are formed should be 15% or more (more preferably 20% or more, even more preferably 25% or more, and particularly preferably 30% or more). This sufficiently prevents the object to be fired from being placed on the rib. On the other hand, from the viewpoint of stably placing the fireproof mesh 20 on the frame 10 (on the rib 12), the upper limit of the area of ​​the region where the primary projections are formed is preferably 80% or less, more preferably 75% or less, even more preferably 70% or less, and particularly preferably 65% ​​or less. This ensures that the rib 12 has a width sufficient to allow the fireproof mesh 20 to be placed stably.

[0053] Furthermore, the first protrusions 14 in the first to fourth embodiments are tapered protrusions that become thinner toward the upper end. However, the first protrusions may protrude upward while maintaining a constant thickness. In this case, when several hundred firing objects are supplied from above the firing jig, there is a high possibility that the firing objects will be placed on the upper surfaces of the first protrusions. However, by brushing off the firing objects that have placed on the first protrusions before placing them in the firing furnace, firing defects on the first protrusions can be prevented. However, from the perspective of reducing such work and improving production efficiency, it is preferable to form tapered first protrusions as in the first to fourth embodiments.

[0054] As shown in FIGS. 3, 9, and 10, the refractory mesh 20 in each of the above-described embodiments is placed on the frame 10 so as to contact the upper surface of the frame 10. However, the refractory mesh need only be located above the frame, and does not need to be in contact with the upper surface of the frame. For example, if the width of the openings in the refractory mesh is made smaller than the width of the bases of the tapered first projections, the refractory mesh will be engaged by the bases of the first projections. This allows the upper surface of the frame and the refractory mesh to be spaced apart. This further improves the permeability of high-temperature gas, thereby further improving the heating efficiency of the object to be fired.

[0055] While specific examples of the technology disclosed herein have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and alterations of the specific examples exemplified above.

[0056] The technology disclosed herein includes the following items 1 to 8. The following items 1 to 8 are not limited to the above-described embodiment.

[0057] [Item 1] A tray-shaped frame, a fireproof mesh disposed above the frame; It is equipped with The frame is an outer frame that defines the outer shape of the frame; a rib bridging the outer frame; a plurality of gas passage holes surrounded by the outer frame and the ribs; a first protrusion protruding upward from the rib; It is equipped with a plurality of the fire-resistant meshes are disposed above the frame so as to cover the plurality of gas passage holes, The firing jig, wherein the first projection protrudes from a gap between two adjacent pieces of the refractory mesh above an upper surface of the refractory mesh.

[0058] [Item 2] Item 2. The firing jig according to item 1, wherein the first projection is a tapered projection that narrows toward an upper end.

[0059] [Item 3] 3. The firing jig according to item 1 or 2, wherein the first projections extend continuously along the extension direction of the ribs.

[0060] [Item 4] the frame further includes a second protrusion protruding upward from the outer frame, 4. The firing jig according to any one of items 1 to 3, wherein each of the plurality of refractory meshes is disposed in an area surrounded by the first projections and / or the second projections.

[0061] [Item 5] the frame includes three or more support columns protruding upward from the outer frame and / or the ribs; 5. The firing jig according to any one of items 1 to 4, wherein the height of the support pillar is greater than the height of the primary projection.

[0062] [Item 6] 6. The firing jig according to any one of items 1 to 5, wherein a damming portion higher than the height of the center of the refractory mesh is provided on the outer peripheral edge of the refractory mesh.

[0063] [Item 7] 7. The firing jig according to item 6, wherein the blocking portion is a portion where the outer edge portion of the refractory mesh is folded over.

[0064] [Item 8] 7. The firing jig according to claim 6, wherein the blocking portion is a portion where the outer peripheral edge of the refractory mesh is bent upward. [Explanation of symbols]

[0065] 1: Firing jig 10: Frame 11: Outer frame 12: Rib 13: Gas passage hole 14: 1st protrusion 15:Second protrusion 16: Strut 20: Fireproof mesh 24: Dam section

Claims

1. A tray-shaped frame, a fireproof mesh disposed above the frame; It is equipped with The frame is an outer frame that defines the outer shape of the frame; a rib bridging the outer frame; a plurality of gas passage holes surrounded by the outer frame and the ribs; a first protrusion protruding upward from the rib; It is equipped with a plurality of the fire-resistant meshes are disposed above the frame so as to cover the plurality of gas passage holes, The firing jig, wherein the first projection protrudes from a gap between two adjacent pieces of the refractory mesh above an upper surface of the refractory mesh.

2. The firing jig according to claim 1 , wherein the first projections are tapered projections that become thinner toward their upper ends.

3. The firing jig according to claim 1 , wherein the first projections extend continuously along the extending direction of the ribs.

4. the frame further includes a second protrusion protruding upward from the outer frame, The firing jig according to claim 1 , wherein each of the plurality of refractory meshes is disposed in an area surrounded by the first projections and / or the second projections.

5. the frame includes three or more support columns protruding upward from the outer frame and / or the ribs; The firing jig according to claim 1 , wherein the support pillars have a height greater than that of the first projections.

6. 2. The firing jig according to claim 1, wherein a damming portion higher than a central portion of the refractory mesh is provided on an outer peripheral edge of the refractory mesh.

7. 7. The firing jig according to claim 6, wherein the blocking portion is a folded portion of the outer peripheral edge of the refractory mesh.

8. 7. The firing jig according to claim 6, wherein the blocking portion is a portion obtained by bending an outer peripheral edge of the refractory mesh upward.

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