Inspection method for setters and manufacturing method for honeycomb structure

Abstract

To provide a method of inspecting setters that can be implemented efficiently and further reduce variability when determined.SOLUTION: In a method of inspecting setters interposed between a shelf plate and a honeycomb molded body when the honeycomb molded body is fired, the setter has a mounting surface on which the honeycomb molded body is mounted, and the method comprises a step A1 of imaging the mounting surface using a 3D scanner to acquire a first image of the mounting surface, in which pixels constituting the image have coordinate information and height information, respectively, and a step B1 of determining the presence or absence of a local height abnormality in the mounting surface based on the coordinate information and the height information possessed by pixels constituting the first image of the mounting surface.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a method for inspecting horse chestnuts and a method for manufacturing a honeycomb structure. [Background technology]

[0002] Honeycomb structures are used as filters that capture particulate matter in exhaust gases emitted from internal combustion engines such as diesel engines, and as supports for catalysts that purify toxic gas components such as CO, HC, and NOx.

[0003] Generally, a honeycomb structure has an outer peripheral side wall and partition walls disposed on the inner peripheral side of the outer peripheral side wall to separate a plurality of cells that form flow paths from the first bottom surface to the second bottom surface. The honeycomb structure can be manufactured by kneading a raw material composition obtained by appropriately adding various additives to a ceramic raw material, a pore-forming material, a binder, and a dispersion medium to form a clay, and then extruding the resulting clay through a die that defines a predetermined cell structure to produce a honeycomb formed body. This honeycomb formed body is then cut to a predetermined length, dried, and then fired.

[0004] When carrying out the firing process, the honeycomb formed body is placed on a shelf plate with one bottom surface facing downward, and is then loaded into a firing furnace together with the shelf plate. At this time, in order to prevent the honeycomb formed body from adhering to the shelf plate and to improve the quality of the bottom surface of the honeycomb structure after firing, a firing base plate called a "tochi" is interposed between the shelf plate and the honeycomb formed body, preventing direct contact between the honeycomb formed body and the shelf plate. For example, tochi is known to be formed by molding and firing ceramic materials (Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-82403 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-98123 Summary of the Invention [Problem to be solved by the invention]

[0006] The quality of the horse chestnut mounting surface that comes into contact with the bottom surface of the honeycomb formed body during the firing process affects the quality of the honeycomb structure obtained after firing. For example, if the horse chestnut mounting surface has localized irregularities, smooth firing shrinkage at the contact area with the horse chestnut may be hindered, which may cause deformation or cracking of the partition walls at the bottom surface of the honeycomb structure. Furthermore, if the horse chestnut mounting surface has localized dirt, color transfer may occur to the bottom surface of the honeycomb structure, causing discoloration.

[0007] For this reason, the surface on which the horse chestnut is placed must be smooth enough not to interfere with the firing shrinkage of the honeycomb formed body, and have a clean appearance. In particular, in recent years, honeycomb structures have become thinner in wall thickness (making their manufacture more difficult), and defects such as cracks and deformations in the partition walls occur frequently during firing, so stricter quality control is required for the surface on which the horse chestnut is placed.

[0008] However, conventionally, inspection of the horse chestnut mounting surface has been performed visually by humans, and there have been cases where abnormalities in the horse chestnut mounting surface have gone unnoticed. In such cases, there has been a problem in that the frequency of honeycomb structures that do not meet quality standards is increased, resulting in a decrease in yield. In addition, since inspections performed by humans are sensory inspections, there is variation in judgment. Furthermore, height gauges are sometimes used during inspections to measure the height of localized irregularities on the horse chestnut mounting surface, but this inspection takes time.

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide, in one embodiment, a method for inspecting horse chestnuts that can be carried out efficiently and that contributes to reducing the variability in judgment. In another embodiment, an object of the present invention is to provide a method for manufacturing a honeycomb structure using such an inspection method. [Means for solving the problem]

[0010] The present inventors have conducted extensive research to solve the above problems and have completed the present invention, which is exemplified below. [Aspect 1] A method for inspecting a horse chestnut interposed between a shelf plate and a honeycomb formed body when firing the honeycomb formed body, The tochi has a mounting surface for mounting the honeycomb molded body, and a step A1 of capturing an image of the mounting surface using a 3D scanner to obtain a first image of the mounting surface, each pixel of which has coordinate information and height information; a step B1 of determining whether or not there is a local height abnormality on the placement surface based on coordinate information and the height information of pixels constituting the first image of the placement surface; An inspection method including: [Aspect 2] The inspection method described in aspect 1 includes the step B1 being carried out based on whether or not an area satisfying a predetermined height abnormality condition exists within the first image of the placement surface and is spread so as to satisfy a predetermined size condition. [Aspect 3] The inspection method described in aspect 1 or 2, wherein step B1 includes calculating a difference or ratio between an average height calculated based on height information possessed by all pixels constituting the first image of the placement surface and a height possessed by each pixel constituting the first image of the placement surface. [Aspect 4] The inspection method according to any one of aspects 1 to 3, wherein the first image is provided as a heat map in which coordinate information and height information are associated with each other. [Aspect 5] The 3D scanner; A first image processing unit capable of performing the step B1 by image processing the first image acquired by the 3D scanner; an output unit capable of outputting the result of the step B1 performed by the first image processing unit; The inspection method according to any one of Aspects 1 to 4, wherein the step A1 and the step B1 are carried out by an inspection device comprising: [Aspect 6] The inspection device is disposed at a position where it can inspect the conker on the conveyor, the inspection device includes a robot capable of removing the horse chestnut from the conveyor and a transport controller capable of controlling the robot, The inspection method described in aspect 5, wherein when the inspection device performs the inspection method on the horse chestnut on the conveyor and determines that there is a local height abnormality, the robot is controlled to remove the horse chestnut from the conveyor. [Aspect 7] carrying out the testing method according to any one of aspects 1 to 6; A step of placing the horse chestnut that is determined to have no local height abnormality on a shelf board as a result of carrying out the inspection method; a step of preparing a honeycomb formed body having an outer peripheral side wall and partition walls disposed on an inner peripheral side of the outer peripheral side wall and partitioning a plurality of cells that form a flow path from a first bottom surface to a second bottom surface; A method for manufacturing a honeycomb structure, comprising: a step of placing the honeycomb formed body on the horse chestnut on the shelf plate so that the first bottom surface or the second bottom surface is in contact with the placement surface of the horse chestnut, and firing the honeycomb formed body. [Aspect 8] A method for inspecting a horse chestnut interposed between a shelf plate and a honeycomb formed body when firing the honeycomb formed body, The tochi has a mounting surface for mounting the honeycomb molded body, and a process A2 of capturing an image of the mounting surface using a camera to obtain a second image of the mounting surface, wherein each pixel constituting the image has coordinate information and brightness information; a step C2 of determining whether or not there is localized dirt on the placement surface based on the coordinate information and the luminance information of pixels constituting the second image of the placement surface; An inspection method including: [Aspect 9] An inspection method described in aspect 8, wherein step C2 is carried out based on whether or not an area satisfying predetermined brightness abnormality conditions exists in the second image of the placement surface and is spread so as to satisfy predetermined size conditions. [Aspect 10] The inspection method described in aspect 8 or 9, wherein step C2 includes calculating the difference or ratio between an average brightness calculated based on brightness information possessed by all pixels constituting the second image of the placement surface and the brightness possessed by each pixel constituting the second image of the placement surface. [Aspect 11] The camera; a second image processing unit capable of performing step C2 by image processing the second image acquired by the camera; an output unit capable of outputting the result of step C2 performed by the second image processing unit; 11. The inspection method according to any one of Aspects 8 to 10, wherein the step A2 and the step C2 are carried out by an inspection device comprising: [Aspect 12] The inspection device is disposed at a position where it can inspect the conker on the conveyor, the inspection device includes a robot capable of removing the horse chestnut from the conveyor and a transport controller capable of controlling the robot, An inspection method according to aspect 11, wherein when the inspection device performs the inspection method on the horse chestnut on the conveyor and determines that there is localized contamination, the robot is controlled to remove the horse chestnut from the conveyor. [Aspect 13] carrying out the testing method according to any one of aspects 8 to 12; A step of placing the horse chestnut that is determined to have no localized dirt on a shelf board as a result of carrying out the inspection method; a step of preparing a honeycomb formed body having an outer peripheral side wall and partition walls disposed on an inner peripheral side of the outer peripheral side wall and partitioning a plurality of cells that form a flow path from a first bottom surface to a second bottom surface; A method for manufacturing a honeycomb structure, comprising: a step of placing the honeycomb formed body on the horse chestnut on the shelf plate so that the first bottom surface or the second bottom surface is in contact with the placement surface of the horse chestnut, and firing the honeycomb formed body. [Aspect 14] A method for inspecting a horse chestnut interposed between a shelf plate and a honeycomb formed body when firing the honeycomb formed body, The tochi has a mounting surface for placing the honeycomb molded body, and a camera-type 3D scanner is used to capture an image of the mounting surface, and a first image of the mounting surface, in which each pixel constituting the image has coordinate information and height information, and a second image of the mounting surface, in which each pixel constituting the image has coordinate information and brightness information; A3. a step B3 of determining whether or not there is a local height abnormality on the placement surface based on coordinate information and the height information of pixels constituting the first image of the placement surface; a step C3 of determining whether or not there is localized dirt on the placement surface based on the coordinate information and the luminance information of pixels constituting the second image of the placement surface; An inspection method including: [Aspect 15] An inspection method described in aspect 14, wherein step B3 is carried out based on whether or not an area satisfying predetermined height abnormality conditions exists within the first image of the placement surface and is spread so as to satisfy predetermined size conditions. [Aspect 16] An inspection method described in aspect 14 or 15, wherein step B3 includes calculating the difference or ratio between an average height calculated based on height information possessed by all pixels constituting the first image of the placement surface and the height possessed by each pixel constituting the first image of the placement surface. [Aspect 17] 17. The inspection method according to any one of aspects 14 to 16, wherein the first image is provided as a heat map in which coordinate information and height information are associated with each other. [Aspect 18] An inspection method described in any of aspects 14 to 17, wherein step C3 is performed based on whether or not an area satisfying predetermined brightness abnormality conditions exists in the second image of the placement surface and is spread so as to satisfy predetermined size conditions. [Aspect 19] An inspection method described in any of aspects 14 to 18, wherein step C3 includes calculating the difference or ratio between an average brightness calculated based on brightness information possessed by all pixels constituting the second image of the placement surface and the brightness possessed by each pixel constituting the second image of the placement surface. [Aspect 20] The camera-type 3D scanner; A first image processing unit capable of performing step B3 by image processing the first image acquired by the camera-type 3D scanner; A second image processing unit capable of performing step C3 by image processing the second image acquired by the camera-type 3D scanner; an output unit capable of outputting a result of the step B3 performed by the first image processing unit and a result of the step C3 performed by the second image processing unit; 20. The inspection method according to any one of aspects 14 to 19, wherein the step A3, the step B3, and the step C3 are performed by an inspection device including the following: [Aspect 21] The inspection device is disposed at a position where it can inspect the conker on the conveyor, the inspection device includes a robot capable of removing the horse chestnut from the conveyor and a transport controller capable of controlling the robot, An inspection method according to aspect 20, in which, when the inspection device performs the inspection method on the horse chestnut on the conveyor and determines that there is a local height abnormality and / or that there is local dirt, the robot is controlled to remove the horse chestnut from the conveyor. [Aspect 22] carrying out the testing method according to any one of aspects 14 to 21; A step of placing the horse chestnut that has been determined to have no local height abnormality and no local dirt on a shelf board as a result of carrying out the inspection method; a step of preparing a honeycomb formed body having an outer peripheral side wall and partition walls disposed on an inner peripheral side of the outer peripheral side wall and partitioning a plurality of cells that form a flow path from a first bottom surface to a second bottom surface; A method for manufacturing a honeycomb structure, comprising: a step of placing the honeycomb formed body on the horse chestnut on the shelf plate so that the first bottom surface or the second bottom surface is in contact with the placement surface of the horse chestnut, and firing the honeycomb formed body. [Effects of the Invention]

[0011] According to the horse chestnut inspection method of one embodiment of the present invention, the information required for the inspection can be obtained quickly by using a 3D scanner, a camera, or a camera-type 3D scanner, so that the inspection can be carried out efficiently. Furthermore, according to this inspection method, the inspection can be carried out based on highly objective information, so that horse chestnut inspection can be carried out with little variability in judgment. As a result, the inspection accuracy is improved, and therefore, this horse chestnut inspection method also contributes to improving the yield of honeycomb structures. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view schematically showing a wall-through type honeycomb structure. [Figure 2] FIG. 2 is a schematic cross-sectional view of a wall-through honeycomb structure when observed in a cross section parallel to the cell extension direction. [Figure 3] FIG. 1 is a perspective view schematically showing a wall-flow type pillar-shaped honeycomb structure. [Figure 4] 1 is a schematic cross-sectional view of a wall-flow type pillar-shaped honeycomb structure when observed from a cross section parallel to the cell extension direction. FIG. [Figure 5] FIG. 2 is a schematic exploded perspective view for explaining the positional relationship between a honeycomb formed body, a horse chestnut, and a shelf plate. [Figure 6] This is an example of a heat map of the placement surface of a horse chestnut taken using a 3D scanner. [Figure 7] 1 is an example of an image having coordinate information and brightness information of the placement surface of the horse chestnut captured using a camera. [Figure 8-1] 1 is a schematic side view for explaining the configuration of an inspection device according to a first embodiment of the present invention. [Figure 8-2]FIG. 10 is a schematic side view for explaining the configuration of an inspection device according to a second embodiment of the present invention. [Figure 8-3] FIG. 10 is a schematic side view for explaining the configuration of an inspection device according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Next, embodiments of the present invention will be described in detail with reference to the drawings. It should be understood that the present invention is not limited to the following embodiments, and that appropriate design changes and improvements may be made based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention.

[0014] <1. Honeycomb structure> A honeycomb structure according to one embodiment of the present invention has an outer peripheral sidewall and partition walls disposed on the inner peripheral side of the outer peripheral sidewall, which partition a plurality of cells that form a flow path from the first bottom surface to the second bottom surface. In one embodiment, the honeycomb structure is provided as a wall-through or wall-flow columnar honeycomb structure. The honeycomb structure may be used for various industrial purposes, such as heat sinks, filters (e.g., GPFs and DPFs), catalyst carriers, sliding parts, nozzles, heat exchangers, electrical insulating members, and semiconductor manufacturing equipment parts. In particular, the honeycomb structure is suitable for use as a filter for capturing particulate matter contained in exhaust gases from internal combustion engines, boilers, etc., or as a catalyst carrier for exhaust gas purification catalysts. In particular, the honeycomb structure is suitable for use as an exhaust gas filter and / or catalyst carrier for automobiles.

[0015] 1 and 2 show a schematic perspective view and a cross-sectional view, respectively, of a wall-through honeycomb structure 100. The honeycomb structure 100 includes an outer peripheral sidewall 102 and partition walls 112 disposed on the inner peripheral side of the outer peripheral sidewall 102. The partition walls 112 define a plurality of parallel cells 108 that form a flow path from a first bottom surface 104 to a second bottom surface 106. In the honeycomb structure 100, both ends of each cell 108 are open. Exhaust gas that flows into one cell 108 from the first bottom surface 104 is purified while passing through the cell and then flows out from the second bottom surface 106. Note that, although the first bottom surface 104 is defined as the upstream side of the exhaust gas and the second bottom surface 106 is defined as the downstream side of the exhaust gas, the distinction between the first and second bottom surfaces is for convenience's sake. Alternatively, the second bottom surface 106 may be defined as the upstream side of the exhaust gas and the first bottom surface 104 as the downstream side of the exhaust gas.

[0016] 3 and 4 are a schematic perspective view and a cross-sectional view, respectively, of a wall-flow type honeycomb structure 200. This honeycomb structure 200 includes an outer peripheral side wall 202 and partition walls 212 disposed on the inner peripheral side of the outer peripheral side wall 202 and defining a plurality of parallel cells 208a, 208b that form a fluid flow path from a first bottom surface 204 to a second bottom surface 206. In the honeycomb structure 200, the plurality of cells 208a, 208b can be classified into a plurality of first cells 208a that are arranged inside the outer peripheral side wall 202, extend from the first bottom surface 204 to the second bottom surface 206, have openings on the first bottom surface 204, and have plugging portions 209 on the second bottom surface 206, and a plurality of second cells 208b that are arranged inside the outer peripheral side wall 202, extend from the first bottom surface 204 to the second bottom surface 206, have plugging portions 209 on the first bottom surface 204, and have openings on the second bottom surface 206. In this honeycomb structure 200, the first cells 208a and the second cells 208b are arranged alternately adjacent to each other with partition walls 212 sandwiched therebetween.

[0017] When exhaust gas containing particulate matter such as soot is supplied to the first bottom surface 204 on the upstream side of the honeycomb structure 200, the exhaust gas is introduced into the first cells 208a and travels downstream within the first cells 208a. Because the first cells 208a have plugging portions 209 on the second bottom surface 206 on the downstream side, the exhaust gas passes through the partition walls 212 that separate the first cells 208a and the second cells 208b and flows into the second cells 208b. Since the particulate matter cannot pass through the partition walls 212, it is captured and deposited within the first cells 208a. After the particulate matter is removed, the clean exhaust gas that has flowed into the second cells 208b travels downstream within the second cells 208b and flows out from the second bottom surface 206 on the downstream side. Here, the first bottom surface 204 is defined as the upstream side of the exhaust gas, and the second bottom surface 206 is defined as the downstream side of the exhaust gas, but the distinction between the first bottom surface and the second bottom surface is for convenience, and the second bottom surface 206 may be defined as the upstream side of the exhaust gas, and the first bottom surface 204 may be defined as the downstream side of the exhaust gas.

[0018] The shape of the bottom surface of the honeycomb structure is not limited, and may be, for example, a circular shape, an elliptical shape, a racetrack shape, an oval shape, or other round shape, a polygonal shape such as a triangular shape or a square shape, or other irregular shapes. The honeycomb structure shown in the figure has a circular bottom surface shape and is cylindrical as a whole.

[0019] Although there are no limitations on the shape of the cells in a cross section perpendicular to the flow direction of the cells, a quadrangle, a hexagon, an octagon, or a combination thereof is preferred. Among these, a square and a hexagon are preferred. By using such a cell shape, it is possible to reduce the pressure loss when a fluid is flowed through the columnar honeycomb structure.

[0020] The height of the honeycomb structure (the length from the first bottom surface to the second bottom surface) is not particularly limited and may be appropriately set depending on the application and required performance. The height of the honeycomb structure can be, for example, 40 mm to 450 mm, and typically 44 to 170 mm. There are also no particular limitations on the relationship between the height of the honeycomb structure and the maximum diameter of each bottom surface (the maximum length of the diameters passing through the center of gravity of each bottom surface of the honeycomb structure). Therefore, the height of the honeycomb structure may be longer than the maximum diameter of each bottom surface, or the height of the honeycomb structure may be shorter than the maximum diameter of each bottom surface. For example, the maximum diameter of each bottom surface of the honeycomb structure may be 50 to 400 mm, and typically 76 to 185 mm.

[0021] The cell density of the honeycomb structure (the number of cells per unit cross-sectional area perpendicular to the cell extension direction) is not particularly limited, but is preferably, for example, 6 to 2000 cells / square inch (0.9 to 310 cells / cm). 2 ), preferably 50 to 1500 cells / in² (7.8 to 232.5 cells / cm²) 2 ), and particularly preferably 300 to 1200 cells / square inch (46.5 to 186 cells / cm 2 Here, the cell density is calculated by dividing the total number of cells on one side of the bottom surface (when plugged cells exist, the calculation is performed assuming that the cells are not plugged) by the bottom area of ​​the honeycomb structure excluding the peripheral side wall.

[0022] The thickness of the partition walls in the honeycomb structure is preferably 210 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less, from the viewpoint of reducing pressure loss and heat capacity by thinning the walls. Furthermore, the thickness of the partition walls in the honeycomb structure is preferably 50 μm or more, more preferably 60 μm or more, and even more preferably 70 μm or more, from the viewpoint of ensuring strength. The thickness of the partition walls refers to the length of a line segment that crosses the partition walls when the line segment connects the centers of gravity of adjacent cells in a cross section perpendicular to the cell extension direction (height direction of the honeycomb structure).

[0023] The porosity of the partition walls is preferably 45% or more, and more preferably 50% or more, from the viewpoint of suppressing pressure loss and reducing heat capacity by increasing the porosity. Furthermore, the upper limit of the porosity of the partition walls is preferably 60% or less, and more preferably 55% or less, from the viewpoint of ensuring the strength of the honeycomb structure. Therefore, the porosity of the partition walls is preferably, for example, 45 to 60%, and more preferably 50 to 55%. The porosity is measured by mercury intrusion porosimetry using a mercury porosimeter. The mercury intrusion porosimetry is specified in JIS R1655:2003. In this specification, a partition wall sample (a cube with dimensions of length × width × height = approximately 13 mm × approximately 13 mm × approximately 13 mm) of the honeycomb structure is collected from two locations, one near the radial center of the center in the height direction and the other near the periphery, and the porosity is measured by mercury intrusion porosimetry, and the average value is taken as the measured value.

[0024] Materials constituting the partition walls and outer peripheral side walls of the honeycomb structure include, but are not limited to, porous ceramics. Examples of ceramics include cordierite, mullite, zirconium phosphate, aluminum titanate, silicon carbide (SiC), silicon-silicon carbide composites (e.g., Si-bonded SiC), cordierite-silicon carbide composites, zirconia, spinel, indialite, sapphirine, corundum, titania, and silicon nitride. These ceramics may be contained alone or in combination of two or more.

[0025] When a honeycomb structure is used as a catalyst carrier, the surface of the partition wall can be coated with a catalyst according to the purpose. One type of catalyst can be used alone, or two or more types can be used in combination. Examples of catalysts include, but are not limited to, oxidation catalysts (DOCs) for oxidatively burning hydrocarbons (HC) and carbon monoxide (CO) to increase the exhaust gas temperature, PM combustion catalysts for assisting the combustion of PM such as soot, SCR catalysts and NSR catalysts for removing nitrogen oxides (NOx), and three-way catalysts capable of simultaneously removing hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx). The catalyst can appropriately contain, for example, precious metals (e.g., Pt, Pd, Rh), alkali metals (e.g., Li, Na, K, Cs), alkaline earth metals (e.g., Mg, Ca, Ba, Sr), rare earth elements (e.g., Ce, Sm, Gd, Nd, Y, La, Pr), transition metals (e.g., Mn, Fe, Co, Ni, Cu, Zn, Sc, Ti, Zr, V, Cr), etc.

[0026] To manufacture the above-described honeycomb structure, first, a raw material composition containing ceramic raw materials, a dispersion medium, a pore-forming agent, and a binder is kneaded to form a clay, and then the clay is extruded to form a desired honeycomb formed body. After drying the honeycomb formed body, plugging portions are formed on both bottom surfaces of the honeycomb formed body as needed, and the plugging portions are dried. Next, the honeycomb formed body is degreased and fired to manufacture the honeycomb structure.

[0027] <2. Japanese Horse Chestnut> When firing a honeycomb formed body, a horse chestnut is interposed between the shelf plate and the honeycomb formed body. Fig. 5 is an exploded perspective view that shows a schematic view of the horse chestnut 1 being placed on the shelf plate 21, and the honeycomb formed body 20 being placed on the horse chestnut 1 on the shelf plate 21 so that the first bottom surface or the second bottom surface 22 is in contact with the mounting surface 3 of the horse chestnut 1.

[0028] The tortoise 1 can be provided, for example, as a porous, disc-shaped member made of a ceramic material. The tortoise 1 has a lower surface 2 located below and facing the shelf board 21, a mounting surface 3 located above the tortoise 1 opposite the lower surface 2 and at least partially in contact with the bottom surface 22 of the honeycomb molded body 20, and a side surface 4 connecting the outer edges of the lower surface 2 and the mounting surface 3. The lower surface 2 of the tortoise 1 may be provided with a plurality of grooves 7 extending linearly and radially from the center of the lower surface 2. The provision of the grooves 7 makes it possible to prevent a plurality of tortoises 1 from sticking to each other when stacked for storage or the like.

[0029] The material of the horse chestnut 1 is not particularly limited, and for example, various materials that have been conventionally used as the base material of horse chestnuts for firing can be used. For example, it is possible to use materials that are converted into mullite, cordierite, silicon carbide, alumina, or the like when fired at high temperatures.

[0030] The method for forming the tortoise 1 is not particularly limited. For example, a press mold formed according to the shape of the tortoise is used, the raw ceramic material is filled into the mold, and the desired press pressure is applied to form the tortoise. After applying the press pressure, the tortoise molded body is removed from the mold and fired to produce the tortoise. This allows for the mass production of ceramic tortoises.

[0031] <3. Horse chestnut inspection method> According to one embodiment of the present invention, there is provided a method for inspecting a conker that is interposed between a shelf plate and a honeycomb formed body when the honeycomb formed body is fired. Hereinafter, a first embodiment using a 3D scanner, a second embodiment using a camera, and a third embodiment using a camera-type 3D scanner will be described.

[0032] (3-1. First embodiment) The method for inspecting a horse chestnut according to the first embodiment includes the steps of: A step A1 of capturing an image of the placement surface of the tochi using a 3D scanner and acquiring a first image of the placement surface, wherein each pixel constituting the image has coordinate information and height information; a step B1 of determining whether or not there is a local height abnormality on the placement surface based on coordinate information and the height information of pixels constituting the first image of the placement surface; Includes.

[0033] In step A1, a 3D scanner is used to capture an image of the mounting surface of the inspected horse chestnut, thereby obtaining a first image of the mounting surface, in which each pixel constituting the image has coordinate information and height information. The 3D scanner is hardware capable of three-dimensionally measuring the shape of an object and capturing the data as point cloud data. A non-contact 3D scanner is preferred. Examples of non-contact 3D scanners include a laser beam system and a grid pattern light projection system (or a pattern projection system). To improve inspection accuracy, the 3D scanner preferably has a pixel resolution of 100 μm / pixel or less in each of the planar directions (X direction, Y direction) and a pixel resolution of 10 μm / pixel or less in the height direction (Z direction). For example, a 3D scanner with a pixel resolution of 50 to 80 μm / pixel in each of the planar directions (X direction, Y direction) and a pixel resolution of 3 to 7 μm / pixel in the height direction (Z direction) can be used. The point cloud data can be converted into mesh data using software provided with the 3D scanner, and an image (first image) containing coordinate information and height information corresponding to the mounting surface of the horse chestnut can be obtained. When converting the point cloud data into mesh data, various processes such as smoothing, hole filling, and bridging may be performed.

[0034] Furthermore, when capturing images using a 3D scanner, noise can occur due to the projection of lattice pattern light. Therefore, to eliminate noise, it is preferable to subtract the height information for each pixel between an image captured by a 3D scanner of a jig (master jig) that mimics the normal mounting surface of the horse chestnut and the first image. This difference can be considered as the height information for each pixel in the first image. Furthermore, when capturing images of the horse chestnut mounting surface, it is desirable to capture the images from a direction as perpendicular as possible to the mounting surface. Furthermore, to accommodate tilted imaging directions, it is preferable to calculate the surface tilt based on the height information for each pixel in the first image and perform tilt correction to reduce the tilt to zero.

[0035] By using a 3D scanner, it is possible to obtain images containing objective information about the height of each localized area (each pixel on the image) that makes up the conker's mounting surface, enabling more efficient inspections. The first image can be provided, for example, as a heat map in which coordinate information and height information are associated (see Figure 6). In a heat map, height differences are displayed by color, making it easy to visually identify areas with localized height abnormalities. In the image on the left, a locally high height area can be seen on the left side of the conker's mounting surface. In the image on the right, a locally high height area can be seen in the lower right corner of the conker.

[0036] In step B1, the presence or absence of a local height abnormality on the placement surface is determined based on the coordinate information and height information of pixels constituting the first image of the placement surface. This determination can be made by a human or software based on preset criteria. The coordinate information of pixels constituting the first image of the placement surface is information regarding the position of the pixel in the planar direction in the first image. Here, the coordinate information may be expressed as a set of numbers specifying the position of the pixel in the first image, or may be expressed by the position of the pixel in the first image. Furthermore, the height information of pixels constituting the first image of the placement surface is information regarding the position in the direction perpendicular to the plane.

[0037] The criteria for determining whether or not there is a local height abnormality on the mounting surface can be set by collecting, for a large number of horse chestnuts, coordinate information and height information on the mounting surface of the horse chestnuts and a data set relating to the presence or absence of abnormalities in honeycomb structures manufactured using the horse chestnuts, and deriving the causal relationship between the two. As a method for determining whether or not there is an abnormality in a honeycomb structure, for example, there is a method in which an abnormality is determined when at least one of deformation of the partition walls and cracks in the partition walls is found on the bottom surface of the honeycomb structure that was in contact with the horse chestnuts during firing, and a normality is determined when neither is found.

[0038] The criteria for determining whether or not there is a local height abnormality on the placement surface are set in consideration of the following (a) to (d). (a) To minimize the percentage of cases where abnormalities were found in the honeycomb structure even though it was determined that there were no abnormalities in the horse chestnut (horse chestnut OK / honeycomb NG). (b) Minimize the percentage of cases where the honeycomb structure was found to have no abnormality despite the fact that the horse chestnut was judged to have an abnormality (horse chestnut NG / honeycomb OK). (c) The ratio of cases where the horse chestnut is judged to be normal and the honeycomb structure is also normal (horse chestnut OK / honeycomb OK) is to be maximized. (d) The ratio of cases where the horse chestnut is judged to have an abnormality and the honeycomb structure is also found to have an abnormality (horse chestnut NG / honeycomb NG) is increased as much as possible. Among these, the highest priority is to reduce the ratio of horse chestnut OK / honeycomb NG.

[0039] The standard is preferably set so that the ratio of "good tortoise" / "no good to honeycomb" is, for example, 0.1% or less of the number of inspected tortoises, and more preferably 0.02% or less. The standard is also preferably set so that the ratio of "no good tortoise" / "no good to honeycomb" is 0.0.1% or less of the number of inspected tortoises, and more preferably 0.03% or less. However, because whether or not an abnormality occurs in a honeycomb structure is not solely due to an abnormality in the tortoise, it is difficult to achieve a rate of 0%.

[0040] Furthermore, the standard is preferably set so that the ratio of "good tortoise" / "good to honeycomb" is, for example, 99.90% or more of the number of inspected tortoises, and more preferably 99.95% or more. Furthermore, the standard is preferably set so that the ratio of "NG tortoise" / "NG to honeycomb" is 99.90% or more of the number of inspected tortoises, and more preferably 99.94% or more. However, because whether or not an abnormality occurs in a honeycomb structure is not solely due to an abnormality in the tortoise, it is difficult to achieve 100%.

[0041] The causal relationship between the two may be determined by machine learning using the coordinate information and height information of the mounting surface of the horse chestnut and the presence or absence of abnormalities in the honeycomb structure manufactured using the horse chestnut as training data. Prediction accuracy improves when all honeycomb formed bodies to be fired for machine learning are scheduled to be assigned the same product number (i.e., honeycomb formed bodies with the same design specifications). Inspection accuracy improves when all honeycomb formed bodies to be fired for machine learning are scheduled to be assigned the same product number (i.e., honeycomb formed bodies with the same design specifications). Known learning models such as neural networks and support vector machines can be used for machine learning. Deep learning may be used when training the neural network.

[0042] In one embodiment, step B1 includes performing the determination based on whether or not a region satisfying a predetermined condition for height abnormality exists in the first image of the placement surface and spreads so as to satisfy a predetermined size condition. The predetermined condition for height abnormality can be, for example, a condition regarding a difference or ratio with respect to the average height of the placement surface. Furthermore, the predetermined size condition can be a condition regarding the area or diameter (circle equivalent diameter, etc.) of a continuous region satisfying the condition regarding a difference or ratio with respect to the average height of the placement surface. According to the inventor's experiments, for example, a continuous region higher than X mm (selected from 0.1≦X≦0.2) with respect to the average height of the placement surface is Y mm. 2When there is an area of ​​more than one location with an area of ​​X mm (selected from 0.2≦Y≦0.3) or more, it is determined that there is a local height abnormality on the mounting surface, thereby achieving high inspection accuracy. In addition, when the total area of ​​the dispersion region higher than X mm (selected from 0.1≦X≦0.2) with respect to the average height of the mounting surface of the conker is Z mm 2 Even when Z is equal to or greater than Z (selected from the group consisting of 0.1≦Z≦1.0), it is determined that a local height abnormality exists on the placement surface, thereby achieving even higher inspection accuracy. Therefore, in one embodiment, step B1 includes calculating a difference or a ratio between an average height calculated based on height information possessed by all pixels constituting the first image of the placement surface and a height possessed by each pixel constituting the first image of the placement surface.

[0043] Step A1 and step B1 may be performed by an inspection device. Fig. 8-1 shows a schematic side view for explaining the configuration of an inspection device 810 according to a first embodiment of the present invention. The inspection device 810 includes a 3D scanner 811, a first image processing unit 814 capable of performing step B1 by image processing the first image acquired by the 3D scanner 811, an output unit 813 capable of outputting the results of step B1 performed by the first image processing unit 814, and an imaging controller 812 capable of controlling the 3D scanner 811.

[0044] Examples of the output unit 813 include display devices such as LCDs and organic EL displays. The functions of the first image processing unit 814 can be executed by software installed on a computer such as a personal computer, mainframe, or workstation. For example, the software can be that provided with the 3D scanner 811 or commercially available image processing software.

[0045] The inspection device 810 can be set at a position where the tortoise 818 on the conveyor 815 can be inspected. The inspection device 810 may also be equipped with a robot 816 that can remove the tortoise 818 from the conveyor 815. As the robot 816, for example, an industrial robot such as a six-axis vertical articulated robot or a three-axis vertical articulated robot can be used. The robot 816 can have a hand 816a that can grasp or suck the tortoise 817. The robot 816 can be controlled by a transport controller 840 .

[0046] The procedure for performing step A1 and step B1 using the inspection device 810 will be described. The tortoise 818 on the conveyor 815 is transported to an inspection position by the 3D scanner 811 and then stopped temporarily. The conveyor 815 can be controlled by a transport controller 840. Whether the tortoise 818 has been transported to the inspection position can be determined, for example, by using a sensor (not shown). In one embodiment, when the sensor confirms that the tortoise 818 is in the inspection position, the confirmation result is sent to the imaging controller 812, which then automatically controls the 3D scanner 811, and the 3D scanner 811 captures an image of the surface on which the tortoise 818 is placed. Alternatively, when the sensor confirms that the tortoise 818 is in the inspection position, a human may operate the imaging controller 812 to cause the 3D scanner 811 to capture an image of the surface on which the tortoise 818 is placed. When the 3D scanner 811 captures an image of the mounting surface of the tortoise 818, the imaging controller 812 acquires an image (first image) having coordinate information and height information corresponding to the mounting surface of the tortoise (step A1). The first image can be output from the output unit 813.

[0047] Next, the first image processing unit 814 that receives the first image from the imaging controller 812 determines whether there is a local height abnormality on the mounting surface of the tortoise 818 based on the coordinate information and height information of the pixels that constitute the first image of the mounting surface of the tortoise 818 (step B1). This determination can be made in light of a preset standard.

[0048] If the inspection determines that there is no local height abnormality, the transport controller 840 starts the conveyor 815 again and sends the tortoise 818 to the next process. On the other hand, if it determines that there is a local height abnormality, the transport controller 8402 starts the conveyor 815 again, transports the tortoise 818 to a predetermined position, stops the conveyor, and controls the robot 816 to remove the tortoise 817 from the conveyor 815. For example, the robot 816 can pick up the tortoise 817 that is determined to have a local height abnormality and transport it onto a slope 819. When the tortoise 817 is released from the suction on the slope 819, it slides down the slope 819 and is collected in a predetermined collection box (not shown). The transport controller 840 may be operated manually, or a system may be constructed in which the inspection results are automatically sent to the transport controller 840, and the transport controller 840 automatically controls the conveyor 815 and the robot 816.

[0049] (3-2. Second embodiment) The method for inspecting a horse chestnut according to the second embodiment is as follows: A step A2 of capturing an image of the placement surface of the horse chestnut using a camera to obtain a second image of the placement surface, wherein each pixel constituting the image has coordinate information and brightness information; a step C2 of determining whether or not there is localized dirt on the placement surface based on the coordinate information and the luminance information of pixels constituting the second image of the placement surface; Includes:

[0050] In step A2, a camera is used to capture an image of the mounting surface of the inspected horse chestnut to obtain a second image of the mounting surface, in which each pixel constituting the image has coordinate information and brightness information. The camera is not particularly limited as long as it can obtain a second image having coordinate information and brightness information of the horse chestnut mounting surface. For example, a digital camera capable of obtaining a two-dimensional image having coordinate information and brightness information of the horse chestnut mounting surface can be suitably used. While either a monochrome camera or a color camera may be used, a color camera that can obtain color information in addition to brightness information is preferred. When using a color camera, the brightness information may be the brightness value (intensity) of any one of the red (R), green (G), and blue (B) components, or may be a brightness value (intensity) based on all color components (e.g., a total or average value). However, when determining the presence or absence of reddish-black stains, it is easy to obtain an image with contrast for the blue (B) component. Therefore, it is preferable that the second image be an image in which at least the brightness of the blue (B) component is extracted, and more preferably an image in which only the brightness of the blue (B) component is extracted. The digital camera preferably has a pixel resolution of 100 μm / pix or less in each of the planar directions (X direction, Y direction), and for example, a camera with a pixel resolution of 50 to 80 μm / pix in each of the planar directions (X direction, Y direction) can be used.

[0051] By using a camera, it is possible to obtain an image containing objective information about the brightness of each local area (each pixel on the image) on the horse chestnut placement surface, which allows for efficient inspection. The second image can be provided, for example, as an image in which coordinate information and brightness information are associated by brightness (see Figure 7). In the image, the stain on the right side of the horse chestnut placement surface is visually recognized as a locally low brightness (dark) area.

[0052] In step C2, the presence or absence of localized dirt on the placement surface is determined based on the coordinate information and brightness information of the pixels constituting the second image of the placement surface. This determination can be made by a human or software based on preset criteria. The coordinate information of the pixels constituting the second image of the placement surface is information about the planar position of the pixel in the second image. Here, the coordinate information may be expressed as a set of numbers specifying the position of the pixel in the second image, or may be expressed by the position of the pixel in the second image. When imaging the placement surface of the conker, it is desirable to image from a direction as perpendicular to the placement surface as possible. Furthermore, the tilt correction described above may be performed to accommodate cases where the imaging direction is tilted.

[0053] The criteria for determining whether or not there is localized dirt on the mounting surface can be set by collecting, for a large number of horse chestnuts, data sets relating to the coordinate information and brightness information of the mounting surface of the horse chestnuts and the presence or absence of discoloration in honeycomb structures manufactured using the horse chestnuts, and deriving the causal relationship between the two. As a method for determining whether or not there is discoloration in a honeycomb structure, for example, there is a method in which discoloration is determined to be present when discoloration (color transfer from the horse chestnut) is visually observed over a predetermined area on the bottom surface of the honeycomb structure that was in contact with the horse chestnuts during firing, and discoloration is determined to be absent when such discoloration over a predetermined area is not visually observed.

[0054] The criteria for determining whether or not there is localized dirt on the placement surface are set in consideration of the following (a) to (d). (a) To minimize the percentage of cases where discoloration was found in the honeycomb structure even though the horse chestnut was judged to be clean (horse chestnut OK / honeycomb NG). (b) Minimize the percentage of cases where the honeycomb structure did not discolor despite the horse chestnut being judged to be dirty (horse chestnut NG / honeycomb OK). (c) The proportion of cases where the horse chestnut is judged to be free of dirt and the honeycomb structure is also free of discoloration (horse chestnut OK / honeycomb OK) is to be maximized. (d) The proportion of cases where the horse chestnut was judged to be dirty and the honeycomb structure was also discolored (horse chestnut NG / honeycomb NG) was increased as much as possible. Among these, the highest priority is to reduce the ratio of horse chestnut OK / honeycomb NG.

[0055] The standard is preferably set so that the ratio of "good horse chestnuts" to "no good honeycomb" is 0.30% or less, more preferably 0.01% or less, relative to the number of horse chestnuts inspected. The standard is also preferably set so that the ratio of "no good horse chestnuts" to "no good honeycomb" is 0.30% or less, more preferably 0.01% or less, relative to the number of horse chestnuts inspected. However, because discoloration of the honeycomb structure is not solely due to horse chestnut stains, it is difficult to achieve a rate of 0%.

[0056] Furthermore, the standard is preferably set so that the ratio of "good horse chestnuts" / "good honeycomb" is, for example, 99.90% or more of the number of horse chestnuts inspected, and more preferably 99.98% or more. Furthermore, the standard is preferably set so that the ratio of "NG horse chestnuts" / "NG honeycomb" is 99.90% or more of the number of horse chestnuts inspected, and more preferably 99.98% or more. However, because whether or not discoloration occurs in a honeycomb structure is not solely due to horse chestnut dirt, it is difficult to achieve a 100% standard.

[0057] The causal relationship between the two may be learned by machine learning using the coordinate information and brightness information of the mounting surface of the horse chestnut and the presence or absence of discoloration of the honeycomb structure manufactured using the horse chestnut as training data. Prediction accuracy improves if all honeycomb formed bodies to be fired for machine learning are to be assigned the same product number (i.e., honeycomb formed bodies with the same design specifications). Known learning models such as neural networks and support vector machines can be used for machine learning. Deep learning may also be used when training the neural network.

[0058] In one embodiment, step C2 includes performing the determination based on whether or not a region satisfying a predetermined condition for luminance abnormality exists in the second image of the placement surface and spreads to satisfy a predetermined size condition. The predetermined condition for luminance abnormality can be, for example, a condition regarding a difference or ratio with respect to the average luminance of the placement surface. The predetermined size condition can also be a condition regarding the area or diameter (circle-equivalent diameter, etc.) of a continuous region satisfying the condition regarding a difference or ratio with respect to the average luminance of the placement surface. According to experiments by the inventors, for example, when the average luminance of the placement surface is taken as 100%, a continuous region having a luminance smaller than X% (selected from 30≦X≦70) is found to be Y mm 2 When there is localized contamination on the placement surface at one or more locations with an area of ​​0.2≦Y≦1.5 or more, it is determined that localized contamination exists on the placement surface, thereby making it possible to obtain high inspection accuracy.

[0059] Therefore, in one embodiment, step C2 includes calculating the difference or ratio between an average brightness calculated based on brightness information possessed by all pixels constituting the second image of the placement surface and the brightness possessed by each pixel constituting the second image of the placement surface.

[0060] Step A2 and step C2 may be performed by an inspection device. Fig. 8-2 shows a schematic side view for explaining the configuration of an inspection device 820 according to a second embodiment of the present invention. The inspection device 820 includes a camera 821, a second image processing unit 824 capable of performing step C2 by image processing a second image acquired by the camera 821, an output unit 823 capable of outputting the result of performing step C2 by the second image processing unit 824, and an imaging controller 822 capable of controlling the camera 821.

[0061] Examples of the output unit 823 include display devices such as LCDs and organic EL displays. The functions of the second image processing unit 824 can be executed by software installed on a computer such as a personal computer, mainframe, or workstation. For example, the software may be that provided with the camera 821 or commercially available image processing software.

[0062] The inspection device 820 can be set at a position where the tortoise 828 on the conveyor 825 can be inspected. The inspection device 820 may also be equipped with a robot 826 that can remove the tortoise 828 from the conveyor 825. As the robot 826, for example, an industrial robot such as a six-axis vertical articulated robot or a three-axis vertical articulated robot can be used. The robot 826 can have a hand 826a that can grasp or suck the tortoise 827. The robot 826 can be controlled by a transport controller 840 .

[0063] The procedure for performing steps A2 and C2 using the inspection device 820 will be described. The tortoise 828 on the conveyor 825 is transported to an inspection position by the camera 821 and then stopped temporarily. The conveyor 825 can be controlled by the transport controller 840. Whether the tortoise 828 has been transported to the inspection position can be determined, for example, by using a sensor (not shown). In one embodiment, when the sensor confirms that the tortoise 828 is at the inspection position, the confirmation result is sent to the imaging controller 822, which then automatically controls the camera 821, and the camera 821 captures an image of the surface on which the tortoise 828 is placed. Alternatively, when the sensor confirms that the tortoise 828 is at the inspection position, a human may operate the imaging controller 822 to cause the camera 821 to capture an image of the surface on which the tortoise 828 is placed. When the camera 821 captures an image of the placement surface of the tortoise 828, the imaging controller 822 acquires an image (second image) having coordinate information and brightness information corresponding to the placement surface of the tortoise 828 (step A2). The second image can be output from the output unit 823.

[0064] Next, the second image processing unit 824 that receives the second image from the imaging controller 822 determines whether there is localized dirt on the mounting surface of the tortoise 828 based on the coordinate information and brightness information of the pixels that constitute the second image of the mounting surface of the tortoise 828 (step C2). This determination can be made in light of a preset standard.

[0065] If the inspection determines that there is no localized contamination, the transport controller 840 starts the conveyor 825 again and sends the tortoise 828 to the next process. On the other hand, if it determines that there is localized contamination, the transport controller 840 starts the conveyor 825 again, transports the tortoise 828 to a predetermined position, stops the conveyor, and controls the robot 826 to remove the tortoise 827 from the conveyor 825. For example, the robot 826 can pick up the tortoise 827 that has been determined to have localized contamination and transport it onto a slope 829. When the tortoise 827 is released from the suction on the slope 829, it slides down the slope 829 and is collected in a predetermined collection box (not shown). The transport controller 840 may be operated by a human, or a system may be constructed in which the inspection results are automatically sent to the transport controller 840, and the transport controller 840 automatically controls the conveyor 825 and the robot 826.

[0066] (3-3. Third embodiment) The method for inspecting a horse chestnut according to the third embodiment is as follows: A step A3 of capturing an image of the placement surface of the tochi using a camera-type 3D scanner, and obtaining a first image of the placement surface, in which each pixel constituting the image has coordinate information and height information, and a second image of the placement surface, in which each pixel constituting the image has coordinate information and brightness information; a step B3 of determining whether or not there is a local height abnormality on the placement surface based on coordinate information and the height information of pixels constituting the first image of the placement surface; a step C3 of determining whether or not there is localized dirt on the placement surface based on the coordinate information and the luminance information of pixels constituting the second image of the placement surface; Includes.

[0067] In step A3, a camera-type 3D scanner is used to capture an image of the placement surface, obtaining a first image of the placement surface, in which each pixel constituting the image has coordinate information and height information, and a second image of the placement surface, in which each pixel constituting the image has coordinate information and brightness information. The camera-type 3D scanner is a device that combines the functions of the aforementioned 3D scanner and a camera, and can simultaneously obtain coordinate information, height information, and brightness information of the conker placement surface. This offers the advantage of being able to quickly inspect both the presence or absence of conker height abnormalities and the presence or absence of dirt. When using a camera-type 3D scanner, the various 3D scanner processes, noise removal, tilt correction, etc. described in the first embodiment can also be performed.

[0068] When capturing images using a camera-based 3D scanner, noise can occur due to the projection of a grid pattern light. Therefore, to remove noise, it is preferable to subtract the height information for each pixel between an image captured by a 3D scanner of a jig (master jig) that mimics the normal mounting surface of the horse chestnut and the first image. This subtraction can be considered as the height information for each pixel in the first image. Furthermore, when capturing images of the horse chestnut mounting surface, it is desirable to capture the images from a direction as perpendicular as possible to the mounting surface. Furthermore, to accommodate tilted imaging directions, it is preferable to calculate the surface tilt based on the height information for each pixel in the first image and perform tilt correction to reduce the tilt to zero.

[0069] By using a camera-based 3D scanner, it is possible to obtain images containing objective information about the height of each localized area (each pixel on the image) that makes up the conker's mounting surface, enabling more efficient inspections. The first image can be provided, for example, as a heat map in which coordinate information and height information are associated (see Figure 6). In a heat map, height differences are displayed by color, making it easy to visually identify areas with localized height abnormalities. In the image on the left, a locally high height area can be seen on the left side of the conker's mounting surface. In the image on the right, a locally high height area can be seen in the lower right corner of the conker.

[0070] Furthermore, by using a camera-type 3D scanner, it is possible to obtain images containing objective information about the brightness of each local area (each pixel on the image) on the horse chestnut's mounting surface, which allows for more efficient inspection. The second image can be provided, for example, as an image in which coordinate information and brightness information are associated by brightness (see Figure 7). In the image, the stain on the right side of the horse chestnut's mounting surface is visually recognized as a locally low brightness (dark) area.

[0071] In step B3, the presence or absence of a local height abnormality on the placement surface is determined based on the coordinate information and the height information of the pixels constituting the first image of the placement surface. The details of step B3 are the same as those described in step B1, so a duplicated description will be omitted.

[0072] In step C3, the presence or absence of localized dirt on the placement surface is determined based on the coordinate information and the brightness information of the pixels that constitute the second image of the placement surface. The details of step C3 are the same as those described in step C2, so a duplicated description will be omitted.

[0073] Steps A3, B3, and C3 may be performed by an inspection device. FIG. 8-3 shows a schematic side view illustrating the configuration of an inspection device 830 according to a third embodiment of the present invention. The inspection device 830 includes a camera-type 3D scanner 831, a first image processing unit 834a capable of performing step B3 by image processing a first image acquired by the camera-type 3D scanner 831, a second image processing unit 834b capable of performing step C3 by image processing a second image acquired by the camera-type 3D scanner 831, an output unit 833 capable of outputting the results of step B3 performed by the first image processing unit 834a and the results of step C3 performed by the second image processing unit, and an imaging controller 832 capable of controlling the camera-type 3D scanner 831.

[0074] Examples of the output unit 833 include display devices such as LCDs and organic EL displays. The functions of the first image processing unit 834a and the second image processing unit 834b can be performed by software installed on a computer such as a personal computer, mainframe, or workstation. For example, the software can be that provided with the camera-type 3D scanner 831 or commercially available image processing software.

[0075] The inspection device 830 can be installed at a position where the tortoise 838 on the conveyor 835 can be inspected. The inspection device 830 may also be equipped with a robot 836 that can remove the tortoise 838 from the conveyor 835. As the robot 836, for example, an industrial robot such as a six-axis vertical articulated robot or a three-axis vertical articulated robot can be used. The robot 836 can have a hand 836a that can grasp or suck the tortoise 837. The robot 836 can be controlled by a transport controller 840 .

[0076] The following describes the procedures for performing steps A3, B3, and C3 using the inspection device 830. The tortoise 838 on the conveyor 835 is transported to an inspection position by the camera-based 3D scanner 831 and then stops temporarily. The conveyor 835 can be controlled by a transport controller 840. Whether the tortoise 838 has been transported to the inspection position can be determined, for example, by using a sensor (not shown). In one embodiment, when the sensor confirms that the tortoise 838 is in the inspection position, the confirmation result is sent to the imaging controller 832, which automatically controls the camera-based 3D scanner 831, and the camera-based 3D scanner 831 captures an image of the surface on which the tortoise 838 is placed. Alternatively, when the sensor confirms that the tortoise 838 is in the inspection position, a human may operate the imaging controller 832 to cause the camera-based 3D scanner 831 to capture an image of the surface on which the tortoise 838 is placed. When the camera-type 3D scanner 831 captures an image of the placement surface of the tortoise 838, a first image and a second image are acquired by the imaging controller 832 (step A3). The first image and the second image can be output from the output unit 833.

[0077] Next, the first image processing unit 834a, which has received the first image from the imaging controller 832, determines whether or not there is a local height abnormality on the placement surface of the tortoise 838 based on the coordinate information and height information of the pixels that make up the first image of the placement surface of the tortoise 838 (step B3). The determination in step B3 can be made in light of preset criteria. Furthermore, the second image processing unit 834b, which has received the second image from the controller 832, determines whether or not there is local dirt on the placement surface of the tortoise 838 based on the coordinate information and brightness information of the pixels that make up the second image of the placement surface of the tortoise 838 (step C3). The determination in step C3 can also be made in light of preset criteria.

[0078] If the inspection determines that there is neither a local height abnormality nor local dirt, the transport controller 840 starts the conveyor 835 again and sends the tortoise 838 to the next process. On the other hand, if it is determined that there is a local height abnormality and / or that there is local dirt, the transport controller 840 starts the conveyor 835 again, transports the tortoise 838 to a predetermined position, stops the conveyor 835, and controls the robot 836 to remove the tortoise 837 from the conveyor 835. For example, the robot 836 can pick up the tortoise 837 that is determined to have a local height abnormality and / or local dirt and transport it onto a slope 839. When the tortoise 837 is released from suction on the slope 839, it slides down the slope 839 and is collected in a predetermined collection box (not shown). The transport controller 840 may be operated by a human, or a system may be established to automatically send the inspection results to the transport controller 840, so that the transport controller 840 automatically controls the conveyor 835 and robot 836.

[0079] <4. Manufacturing method of honeycomb structure> According to one embodiment of the present invention, there is provided a method for manufacturing a honeycomb structure using the above-mentioned method for inspecting a horse chestnut. In this manufacturing method, horse chestnuts that have passed the inspection in advance are used, and therefore the yield of honeycomb structures is improved. In one embodiment, the method comprises: A step of placing the horse chestnuts that have passed the inspection on a shelf board as a result of carrying out the inspection method; a step of preparing a honeycomb formed body having an outer peripheral side wall and partition walls disposed on an inner peripheral side of the outer peripheral side wall and partitioning a plurality of cells that form a flow path from a first bottom surface to a second bottom surface; and firing the honeycomb formed body by placing it on the horse chestnut on the shelf board so that the first bottom surface or the second bottom surface is in contact with the placement surface of the horse chestnut.

[0080] A tortoise that has passed the inspection refers to a tortoise that has been determined to have no local height abnormalities in the inspection method according to the first embodiment, a tortoise that has been determined to have no local dirt in the inspection method according to the second embodiment, and a tortoise that has been determined to have no local height abnormalities and no local dirt in the inspection method according to the third embodiment.

[0081] The honeycomb formed body can be produced, for example, by kneading a raw material composition containing a ceramic raw material, a dispersion medium, a pore-forming agent, and a binder to form a clay, and then extruding and drying the clay. Plugging portions may be formed on both bottom surfaces of the honeycomb formed body.

[0082] The firing step depends on the material composition of the honeycomb formed body, but can be carried out, for example, by heating the calcined body to 1350 to 1600°C and holding it there for 3 to 10 hours. A degreasing step may be carried out before the firing step, or the firing step may be carried out immediately after the degreasing step. The combustion temperature of the binder is about 200°C, and the combustion temperature of the pore-forming material is about 300 to 1000°C. Therefore, the degreasing step may be carried out by heating the honeycomb formed body to a temperature in the range of about 200 to 1000°C. The heating time is not particularly limited, but is usually about 10 to 100 hours. [Example]

[0083] (1. Data Collection) A clay was prepared by mixing and kneading the cordierite raw material, pore former, dispersion medium, organic binder, and dispersant in a predetermined compounding ratio. This clay was put into an extrusion molding machine and extruded through a die of a predetermined shape to obtain a cylindrical honeycomb molded body. Furthermore, after a pressing and firing process, a mullite-based tochi (mounting surface area = 6200 mm) was obtained. 2 The obtained honeycomb molded body was subjected to dielectric drying and hot air drying, and then both bottom surfaces were cut to the specified dimensions. Next, the obtained honeycomb molded body was placed on a shelf board via the horse chest and loaded into a firing furnace, and after degreasing in an air atmosphere, it was further fired in an air atmosphere at 1420°C for 5 hours to obtain a large number of honeycomb structures.

[0084] This honeycomb structure has the following design specifications: Overall shape: Cylinder with a diameter of 118 mm and a height of 91 mm Cell shape in cross section perpendicular to the flow direction: square Cell density (number of cells per unit cross-sectional area): 93 cells / cm 2 Partition wall thickness: 76 μm (nominal value based on the specifications of the nozzle) Material: Cordierite

[0085] The bottom surface of the honeycomb structure obtained, which had been in contact with the surface where the horse chestnut was placed, was visually inspected for the presence or absence of deformation or cracks in the partition walls, and the area per point was inspected to be 3.14 mm 2 The presence or absence of discoloration (color transfer) of a diameter of 2.0 mm or larger was investigated. Additionally, a camera-type 3D scanner was used to record a first image containing coordinate and height information for the mounting surface of the horse chestnut used to fire each honeycomb structure, and a second image containing coordinate and brightness information. The first image was subjected to the aforementioned noise removal and tilt correction using "HALCON," an image processing software from Links Co., Ltd., installed on a PC. The second image was subjected to noise removal using "HALCON," an image processing software from Links Co., Ltd., installed on a PC. In this way, a total of more than 170,000 images were recorded, correlating the properties of the horse chestnut mounting surface with the properties of the bottom surface of the honeycomb structure, and the causal relationship was investigated using "HALCON," an image processing software from Links Co., Ltd. The camera-type 3D scanner was constructed using Keyence Corporation's VJ-H500CX camera, VJ-3000 imaging controller, and CA-DP12X pattern projection lighting. This camera-type 3D scanner uses the pattern projection method, and the following lighting conditions were used: Dimming value: 80 / 100 Exposure time: 7500μsec Number of lights: 8 ·X direction pixel resolution: 75μm / pix ·Y direction pixel resolution: 75μm / pix Z-direction pixel resolution: 5 μm / 1 brightness value

[0086] (2. Relationship between local height abnormalities on the horse chestnut placement surface and deformation or cracks on the bottom surface of the honeycomb structure) Based on the data obtained above, an analysis was conducted to determine the relationship between the local height abnormality on the horse chestnut mounting surface and the presence or absence of deformation or cracks on the bottom surface of the honeycomb structure. As a result, it was found that the continuous area higher than 0.15 mm from the average height of the horse chestnut mounting surface was 0.258 mm. 2 When there is more than one area with an area of ​​0.15mm or more relative to the average height of the surface on which the horse chestnut is placed, the total area of ​​the dispersed area is 0.258mm 2 It was found that the following high inspection accuracy can be achieved by determining that there is a local height abnormality on the tochi placement surface (Tochi NG) when at least one of the following conditions is met, and determining that there is no abnormality otherwise (Tochi OK). (a) The percentage of cases where the honeycomb structure had at least one of deformation and cracks even though the horse chestnut was judged to be normal (horse chestnut OK / honeycomb NG) = 0.02% (b) The percentage of cases where the honeycomb structure had neither deformation nor cracks despite the fact that the horse chestnut was judged to be abnormal (horse chestnut NG / honeycomb OK) = 0.03% (c) The percentage of cases where the horse chestnut was judged to be normal and the honeycomb structure had neither deformation nor cracks (horse chestnut OK / honeycomb OK) = 99.95% (d) The percentage of cases where the tochi was judged to be abnormal and the honeycomb structure had at least one of deformation and cracks (Tochi NG / Honeycomb NG) = 99.94%

[0087] (3. Relationship between localized staining on the surface where the horse chestnut is placed and discoloration on the bottom surface of the honeycomb structure) Based on the data obtained above, the relationship between localized staining on the surface where the horse chestnuts are placed and discoloration on the bottom surface of the honeycomb structure was analyzed. As a result, it was found that, when the average brightness (intensity) of the blue component (B) on the surface where the placement is made is 100%, the continuous area where the brightness (intensity) of the blue component (B) is less than 60% is 1.0 mm. 2When there is more than one spot with an area of ​​the above, it is determined that there is localized dirt on the surface where the tochi is placed (Tochi NG), and otherwise it is determined that there is no dirt (Tochi OK), and it was found that the following high inspection accuracy can be achieved. (a) The percentage of cases where the honeycomb structure was discolored even though the horse chestnut was judged to be clean (horse chestnut OK / honeycomb NG) = 0.01% (b) The percentage of cases where the honeycomb structure did not show any discoloration despite the horse chestnut being judged to be dirty (horse chestnut NG / honeycomb OK) = 0.01% (c) The percentage of cases where the horse chestnut was judged to be clean and the honeycomb structure was not discolored (horse chestnut OK / honeycomb OK) = 99.98% (d) The percentage of cases where the horse chestnut was judged to be dirty and the honeycomb structure was also discolored (horse chestnut NG / honeycomb NG) = 99.99%

[0088] From the above results, it can be seen that there is a high correlation between local height abnormalities on the mounting surface of the horse chestnut and deformation or cracking of the partition walls on the bottom surface of the honeycomb structure to be manufactured. It can also be seen that there is a high correlation between local dirt on the mounting surface of the horse chestnut and discoloration on the bottom surface of the honeycomb structure to be manufactured. Therefore, by utilizing statistical data and setting appropriate standards, it becomes possible to inspect horse chestnuts with high accuracy. [Explanation of symbols]

[0089] 1: Horse chestnut 2: Bottom surface 3: Placement surface 4: Side 7: Groove 20: Honeycomb molded body 21: Shelf 22: Bottom 100: Honeycomb structure 102: Outer wall 104: First bottom surface 106: Second bottom surface 108: Cell 112: Bulkhead 200: Honeycomb structure 202: Outer wall 204: First bottom surface 206: Second bottom surface 208a: First cell 208b: Second cell 209: Plugging part 212: Bulkhead 810: Inspection equipment 811: 3D scanner 812: Imaging controller 813: Output section 814: First image processing unit 815: Conveyor 816: Robot 816a: Hand 817: Horse chestnut 818: Horse chestnut 819: Slope 820: Inspection equipment 821: Camera 822: Imaging controller 823: Output section 824: Second image processing unit 825: Conveyor 826: Robot 826a: Hand 827: Horse chestnut 828: Horse chestnut 829: Slope 830: Inspection equipment 831: Camera-based 3D scanner 832: Imaging controller 833: Output section 834a: First image processing unit 834b: Second image processing unit 835: Conveyor 836: Robot 836a: Hand 837: Horse chestnut 838: Horse chestnut 839: Slope 840: Transport controller

Claims

1. A method for inspecting a horse chestnut interposed between a shelf plate and a honeycomb formed body when firing the honeycomb formed body, The tochi has a mounting surface for mounting the honeycomb molded body, and a step A1 of capturing an image of the mounting surface using a 3D scanner to obtain a first image of the mounting surface, wherein each pixel constituting the image has coordinate information and height information; a step B1 of determining whether or not there is a local height abnormality on the placement surface based on coordinate information and height information of pixels constituting the first image of the placement surface; An inspection method including:

2. The inspection method according to claim 1, wherein step B1 is carried out based on whether or not an area satisfying a predetermined height abnormality condition exists within the first image of the placement surface and is spread so as to satisfy a predetermined size condition.

3. The inspection method according to claim 1, wherein step B1 includes calculating a difference or ratio between an average height calculated based on height information possessed by all pixels constituting the first image of the placement surface and a height possessed by each pixel constituting the first image of the placement surface.

4. The inspection method according to claim 1 , wherein the first image is provided as a heat map in which coordinate information and height information are associated.

5. The 3D scanner; A first image processing unit capable of performing the step B1 by image processing the first image acquired by the 3D scanner; an output unit capable of outputting the result of the step B1 performed by the first image processing unit; The inspection method according to claim 1 , wherein the step A1 and the step B1 are performed by an inspection device comprising:

6. The inspection device is disposed at a position where it can inspect the conker on the conveyor, the inspection device includes a robot capable of removing the horse chestnut from the conveyor and a transport controller capable of controlling the robot, The inspection method according to claim 5, wherein when the inspection device performs the inspection method on the horse chestnut on the conveyor and determines that there is a local height abnormality, the robot is controlled to remove the horse chestnut from the conveyor.

7. A step of carrying out the inspection method according to any one of claims 1 to 6; A step of placing the horse chestnut that is determined to have no local height abnormality on a shelf board as a result of carrying out the inspection method; a step of preparing a honeycomb formed body having an outer peripheral side wall and partition walls disposed on an inner peripheral side of the outer peripheral side wall and partitioning a plurality of cells that form a flow path from a first bottom surface to a second bottom surface; A method for manufacturing a honeycomb structure, comprising: a step of placing the honeycomb formed body on the horse chestnut on the shelf plate so that the first bottom surface or the second bottom surface is in contact with the placement surface of the horse chestnut, and firing the honeycomb formed body.

8. A method for inspecting a horse chestnut interposed between a shelf plate and a honeycomb formed body when firing the honeycomb formed body, The tochi has a mounting surface for mounting the honeycomb molded body, and a step A2 of capturing an image of the mounting surface using a camera to obtain a second image of the mounting surface, wherein each pixel constituting the image has coordinate information and brightness information; a step C2 of determining whether or not there is localized dirt on the placement surface based on the coordinate information and the luminance information of pixels constituting the second image of the placement surface; An inspection method including:

9. The inspection method described in claim 8, wherein step C2 is carried out based on whether or not an area satisfying predetermined brightness abnormality conditions exists in the second image of the placement surface and is spread so as to satisfy predetermined size conditions.

10. The inspection method described in claim 8, wherein step C2 includes calculating the difference or ratio between an average brightness calculated based on brightness information possessed by all pixels constituting the second image of the placement surface and the brightness possessed by each pixel constituting the second image of the placement surface.

11. The camera; a second image processing unit capable of performing step C2 by image processing the second image acquired by the camera; an output unit capable of outputting the result of step C2 performed by the second image processing unit; The inspection method according to claim 8 , wherein the step A2 and the step C2 are performed by an inspection device comprising:

12. The inspection device is disposed at a position where it can inspect the conker on the conveyor, the inspection device includes a robot capable of removing the horse chestnut from the conveyor and a transport controller capable of controlling the robot, The inspection method according to claim 11, wherein when the inspection device performs the inspection method on the horse chestnut on the conveyor and determines that there is localized contamination, the robot is controlled to remove the horse chestnut from the conveyor.

13. A step of carrying out the inspection method according to any one of claims 8 to 12; A step of placing the horse chestnut that is determined to have no localized dirt on a shelf board as a result of carrying out the inspection method; a step of preparing a honeycomb formed body having an outer peripheral side wall and partition walls disposed on an inner peripheral side of the outer peripheral side wall and partitioning a plurality of cells that form a flow path from a first bottom surface to a second bottom surface; A method for manufacturing a honeycomb structure, comprising: a step of placing the honeycomb formed body on the horse chestnut on the shelf plate so that the first bottom surface or the second bottom surface is in contact with the placement surface of the horse chestnut, and firing the honeycomb formed body.

14. A method for inspecting a horse chestnut interposed between a shelf plate and a honeycomb formed body when firing the honeycomb formed body, The tochi has a mounting surface for placing the honeycomb molded body, and a camera-type 3D scanner is used to capture an image of the mounting surface, and a first image of the mounting surface, in which each pixel constituting the image has coordinate information and height information, and a second image of the mounting surface, in which each pixel constituting the image has coordinate information and brightness information, are obtained. A3. a step B3 of determining whether or not there is a local height abnormality on the placement surface based on coordinate information and the height information of pixels constituting the first image of the placement surface; a step C3 of determining whether or not there is localized dirt on the placement surface based on the coordinate information and the luminance information of pixels constituting the second image of the placement surface; An inspection method including:

15. The inspection method described in claim 14, wherein step B3 is carried out based on whether or not an area satisfying a predetermined height abnormality condition exists within the first image of the placement surface and extends to satisfy a predetermined size condition.

16. The inspection method described in claim 14, wherein step B3 includes calculating the difference or ratio between an average height calculated based on height information possessed by all pixels constituting the first image of the placement surface and the height possessed by each pixel constituting the first image of the placement surface.

17. The inspection method according to claim 14 , wherein the first image is provided as a heat map in which coordinate information and height information are associated.

18. The inspection method described in claim 14, wherein step C3 is performed based on whether or not an area satisfying predetermined brightness abnormality conditions exists in the second image of the placement surface and extends to satisfy predetermined size conditions.

19. The inspection method described in claim 14, wherein step C3 includes calculating the difference or ratio between an average brightness calculated based on brightness information possessed by all pixels constituting the second image of the placement surface and the brightness possessed by each pixel constituting the second image of the placement surface.

20. the camera-based 3D scanner; A first image processing unit capable of performing step B3 by image processing the first image acquired by the camera-type 3D scanner; A second image processing unit capable of performing step C3 by image processing the second image acquired by the camera-type 3D scanner; an output unit capable of outputting a result of the step B3 performed by the first image processing unit and a result of the step C3 performed by the second image processing unit; 15. The inspection method according to claim 14, wherein the step A3, the step B3, and the step C3 are performed by an inspection device comprising:

21. The inspection device is disposed at a position where it can inspect the conker on the conveyor, the inspection device includes a robot capable of removing the horse chestnut from the conveyor and a transport controller capable of controlling the robot, 21. The inspection method according to claim 20, wherein when the inspection device performs the inspection method on the horse chestnut on the conveyor and determines that there is a local height abnormality and / or that there is local dirt, the robot is controlled to remove the horse chestnut from the conveyor.

22. A step of carrying out the inspection method according to any one of claims 14 to 21; A step of placing the horse chestnut that has been determined to have no local height abnormality and no local dirt on a shelf board as a result of carrying out the inspection method; a step of preparing a honeycomb formed body having an outer peripheral side wall and partition walls disposed on an inner peripheral side of the outer peripheral side wall and partitioning a plurality of cells that form a flow path from a first bottom surface to a second bottom surface; A method for manufacturing a honeycomb structure, comprising: a step of placing the honeycomb formed body on the horse chestnut on the shelf plate so that the first bottom surface or the second bottom surface is in contact with the placement surface of the horse chestnut, and firing the honeycomb formed body.

Images