JP2005028299A - Plug stuffing method for honeycomb filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide, in a honeycomb filter manufacturing method, a method for selecting efficiently a cell open pit to be subjected to a suitable plug stuffing corresponding to unvarnished sequence conditions from the cell open pits formed in a honeycomb structure. <P>SOLUTION: A method of attaching the plug to the honeycomb filter is the honeycomb filter plug stuffing method for stuffing plugs to the cell open pits in the honeycomb structure in which many cells extending in an axial direction are formed. According to the method, an end surface of the honeycomb structure is divided into a plurality of areas, which are image picked-up so as to share the same cell open pits with the adjacent areas. Based on the predetermined cell open pit each pick-up image, the adjacent cell open pit one by one is asked for according to an adjacent cell detecting rule from the figure information on the cell open pits computed by the image processing. Further, according to the method, the cell pit identification information identifying whether the adjacent cell open pit is a pit for plug stuffing or a pit unnecessary for plug stuffing is assigned to the adjacent cell open pit, and cell pit identification information given uniquely for every pick-up image is shared and, based on the position information of the imaged cell open pit, is reassigned to the cell pit identification information unified in the whole end surface to select the cell open pit to be plug-stuffed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a honeycomb filter having a large number of cells, and relates to plugging for selectively sealing the open ends of the cells.

  A honeycomb filter is mainly used to capture solid particulates in exhaust gas discharged from an internal combustion engine, and is composed of a honeycomb structure made of a porous material, divided by a partition wall and opened at both end faces. Has a large number of cells. One end face of the honeycomb filter is filled with a sealing material at one end of every other cell so as to form a checkered pattern or a checkerboard pattern, and the other end face is a checkered pattern of one end face of the remaining cell. It is sealed to make a reverse checkered pattern. Hereinafter, the end face opening of the cell is distinguished from the cell body and is called a cell opening hole, and sealing the cell opening hole with a filler is called plugging.

  As a technique related to plugging in honeycomb filter manufacture, for example, there is one disclosed in Patent Document 1 below. That is, in the method of filling the end portion of the selected cell of the honeycomb structure with a flowable material, the end surface of the honeycomb structure is covered with a cover formed of a meltable material, and a large number of cell opening holes are closed, and the cover is formed. Scan up to determine the position of the selected cell, generate a first signal indicative of the position of the cell, and a second signal to position the drilling means in response to the first signal It is described that the method comprises a step of generating and positioning a punching means according to the second signal, and making a hole in the cover by the punching means.

Moreover, in the following Patent Document 2, a mask corresponding to each honeycomb formed body is created by making a hole at a position corresponding to a predetermined cell of the sheet attached to the end face of the ceramic honeycomb formed body, and the mask is attached. A method for producing a ceramic body is disclosed, wherein the surface is immersed in a sealing slurry, and the sealing slurry is filled into the cell from the hole drilled in the mask, and the cell pitch is at the drilling position. On the other hand, it is described that it can be automated even for a honeycomb molded body having a diameter of 300 mm or more in which an error of one cell or more occurs.
Japanese Examined Patent Publication No. 2-45481 Japanese Patent Laid-Open No. 2001-300922

When the honeycomb structure becomes large and the number of cell opening holes becomes as large as several thousand to several tens of thousands, the position information of the cell opening holes to be plugged is obtained efficiently and accurately, and the holes are covered. It is important to remove the cover. If the honeycomb structure has almost no distortion and the cell opening holes are shaped almost according to the design drawing, the rotation direction is aligned with the arrangement direction of the cell holes, and the equipment uses numerical control based on the design data. Can respond. However, if the array of cell opening holes is distorted and differs from product to product, or the shape of the cell opening holes themselves is deformed, numerical control technology alone cannot be used, and measurement technology using image processing and position control It is conceivable to use a high-speed machining technique with a high degree of freedom, for example, a laser machining technique.
In Patent Document 1, an optical device such as a television camera is used as a scanning unit for determining the position of a selected cell, and the optical device outputs a signal indicating the position of a cell or a partition wall. Although it is described that a pin-shaped heat drilling element or a laser is used as a method, how to determine a selected cell and its position, and a specific drilling method when using a laser Is not described, and cannot be applied to actual plugging processing.

  In Patent Document 2, cell position recognition and sheet punching are performed by image processing and laser processing, and sheet punching is performed for each small block divided into a plurality of small blocks. It is described. However, the cell position is recognized before the sheet is attached, and the cell position cannot be recognized if the position of the honeycomb formed body is shifted at the time of subsequent sheet attachment or handling. For this reason, in terms of process and equipment, there is a restriction that the sheet must be pasted in a state where the positional information can be retained after the honeycomb formed body is imaged. In addition, the drilling is basically performed by numerical control performed at a cell pitch as designed, and an error of one cell or more occurs when the honeycomb formed body having a greatly deformed cell pitch is applied to the end face at once. For this reason, it is described that the cell of the end face is divided into a plurality of small block groups and is executed for each small block so that the error is within one cell. In addition, it is also described that a slight pitch variation of a cell is dealt with by making a small round hole in a square cell.

However, there is no description of how to set a small block such that the cell pitch is within one cell, and if the predetermined range is determined in advance from the outer diameter or cell pitch of the honeycomb molded body, Depending on the degree of deformation, one or more errors may occur. Also, even if the cell pitch error is within 1 cell, if the cell arrangement is shifted by nearly 1 cell, there is a risk that it will not be perforated so as to have a correct checkerboard pattern, and it is reliable in that it opens to alternate cells. There is a problem with sex. Further, in order to reliably fill the plugging sealing material, it is preferable that the opening hole area is large, but there is a problem in reliability of sealing quality in this respect. Note that the cell position information recognized in the image processing is not specifically described as to what kind of processing is used, but it is assumed that the cell position information is used only for calculating the drilling reference position of the small block. .
Accordingly, the present invention provides a method for selecting an appropriate cell opening hole to be plugged corresponding to a continuous state from the cell opening holes formed in the honeycomb structure in the manufacturing method of the honeycomb filter. The first object is to provide a method that can be efficiently selected.

A first object of the present invention in a plugging method of a honeycomb filter for plugging into a cell opening hole of a honeycomb structure formed with a large number of cells extending in the axial direction is to divide the end face of the honeycomb structure into a plurality of areas. An image is captured so as to share the same cell opening hole with the adjacent area, and the adjacent cells are adjacent to each other according to the adjacent cell search rule based on the graphic information of the cell opening hole calculated by the image processing based on a predetermined cell opening hole for each captured image. This is achieved by sequentially obtaining cell opening holes and assigning cell hole identification information for identifying whether the opening holes are plugging holes or non-plugging holes to adjacent cell opening holes. That is, since the predetermined cell opening hole of the image picked up by dividing into a plurality of areas is used as a reference, the adjacent cell opening hole is sequentially obtained according to the adjacent cell search rule based on the graphic information such as the direction of the cell wall. The cell opening hole to be properly plugged is selected regardless of the deformation of the cell opening hole.
In addition, the second object of the present invention is to unify the cell hole identification information of the cell opening holes uniquely assigned to each captured image based on the position information of the cell opening holes shared and imaged over the entire end face. This is achieved by reassigning the cell hole identification information and selecting the cell opening hole to be plugged. That is, the cell hole identification information of the cell opening hole given for each captured image is reassigned based on the position information of the cell opening hole that is shared and imaged. As compared with the case where the entire end face of the honeycomb structure is reconstructed and the cell hole identification information is reassigned, the selection process is accelerated.

The present invention has the following effects.
1) Reasonably select adjacent cell opening holes according to the continuous state of cell opening holes, and assign data for plugging holes and non-plugging holes alternately to adjacent cell opening holes. A cell opening hole to be plugged can be defined.
2) Based on cell coordinate information calculated by image processing, adjacent cell opening holes are sequentially defined based on a predetermined cell opening hole by an adjacent cell search rule, so that even if the cell is distorted, the cell opening The connection state of the holes can be determined appropriately.
3) By assigning a continuous matrix number to the connected cell opening holes, a series of matrix numbers are given to the cell opening holes to be plugged, so that other cell opening holes to be plugged can be made very easily and short. You can select by time.

FIG. 1 is an example showing a system configuration for carrying out the present invention.
The honeycomb structure 1 has a columnar shape whose outer peripheral surface forms an outer shell, has a large number of cells divided in a number of partitions extending in the axial direction and having a cross section orthogonal to the axial direction in a lattice shape. A sheet for preventing intrusion of the plugging sealing material is affixed to the end face or both end faces. The honeycomb structure 1 is set on the XY stage 2 with one end face up. Above the XY stage 2, a CCD camera 3 as a means for imaging the end face of the honeycomb structure 1 and a laser head 5 as a sheet removing means for irradiating laser light are disposed. The XY stage 2 has a stroke that can move between a position where the honeycomb structure 1 is set and taken out, a position where the image is captured by the CCD camera 3, and a position where the laser beam is irradiated. The control device 4 controls the position of the XY stage 2 and takes in the image information from the CCD camera 3 and the movement information of the XY stage at the time of imaging to obtain the position information and shape of the cell opening hole to be plugged. In addition, the laser beam irradiation control at the time of sheet removal and the position control of the XY stage 2 are performed, and a memory for storing information is provided. In addition, since the cell opening hole is imaged through the sheet, the sheet is light transmissive and is made of a material and thickness that can be melted satisfactorily by the laser beam used.

  The CCD camera 3 requires sufficient image resolution to define the shape of the cell opening hole, and the field of view is determined by the shape and size of the cell opening hole. If the entire end face is imaged in one field of view for a large honeycomb structure, the image resolution will be reduced, and it will not be possible to accurately obtain the position information for calculating the position and shape of the cell opening hole. It is desirable to do. Further, in order to perform processing with a laser beam at high speed, it is common to perform a deflection of a light beam mechanically or electrically using a galvanometer and swing it in the traveling direction. Hereinafter, the processing range is determined by the laser processing machine to be used. If the deflection width of the light beam is large, the processing range is widened, but the laser beam is irradiated obliquely with respect to the processing surface as the distance from the irradiation center increases. For this reason, even if the entire end face is within the processing range, a difference occurs in the irradiation position and the sheet melting state in the central portion and the peripheral portion. Therefore, it is important to set an area (hereinafter, referred to as a processing area) where the sheet can be removed with an accuracy that does not cause a plugging failure, and to perform processing according to this area.

The following is an example of a substantially cylindrical honeycomb structure 1 used for DPF, in which about 15000 square-shaped cell opening holes each having a side of about 1 mm are formed on one end surface by a partition wall formed in a lattice shape. The present invention will be described below.
The cell opening holes to be plugged may be selected so that one end face and the other end face have an opposite checkerboard pattern. For this purpose, basically, the adjacent cell opening holes are rationally selected according to the continuous state of the cell opening holes, and the adjacent cell opening holes are set based on the cell opening holes set in advance for plugging. Cell hole identification information for identifying whether a hole is not used for plugging or a hole for plugging may be allocated so that data for plugging holes and data for non-plugging holes are alternated. For this reason, it is preferable to mark the reference hole set to be plugged so as to be recognized by a sensor or the like. In addition, on the one end surface side, any hole may be used as the reference hole to be plugged, so there is no need to make a marking. In this case, the reference hole on the other end surface constitutes a checkered pattern on the one end surface side. It is necessary to automatically or artificially select at least one opening hole from cells different from the cell to be performed. In the following description, it is assumed that the reference hole on one end side is also provided with a marking that can be identified by image processing, for example, a black circle or a through hole.

A specific example of a method for selecting a cell opening hole position to be plugged will be described with reference to FIG.
First, as shown in S <b> 1 of FIG. 2, one end surface of the honeycomb structure 1 is imaged by the CCD camera 3. The image resolution for measuring the cell opening hole of the above size with good accuracy is about 0.1 mm / pixel, and for this purpose, it is assumed that the end face is divided into four and imaged. Imaging is performed by moving the XY stage 2 so that the end face is divided into four areas. Schematic diagrams of the respective captured images G1 to G4 are shown in FIGS. 3A to 3D, and the same cell opening hole is included in the overlapping portion (shown by hatching) so as to partially overlap the adjacent area. Take an image as shown. Subsequently, as shown in S2, the control device 4 performs image processing on the captured image, and based on graphic information of each cell opening hole for each image, centroid coordinates (position information) of each cell opening hole, Find area, side length, diagonal length, etc.

  Next, as shown in S <b> 3, the control device 4 defines a cell opening hole adjacent to an arbitrary cell opening hole, and assigns continuous matrix numbers as cell hole identification information. The cell opening holes having the same row number are connected in a rational arrangement in the row direction in the column number order, and the cell opening holes having the same column number are arranged in the column direction in the row number order. Represents being connected. However, when trying to define the adjacent cell opening hole based on the centroid position of each cell opening hole, the honeycomb structure in which the cell arrangement is shifted or the cell opening hole is deformed due to cell distortion or the like, There may be cases where a reasonable row or column direction cannot be obtained due to variations in distance between centroids. Therefore, the adjacent cell opening hole is defined according to the adjacent cell search rule described in detail below based on the graphic information of the cell opening hole such as the direction of the cell partition wall.

The adjacent cell search rule will be described.
The cell opening hole for the search start may be arbitrarily determined, but in this description, among the centroid coordinates of the cell opening hole in the image, for example, the centroid coordinates closest to the intersection coordinates of the edge outline and the image boundary line The cell opening hole having this centroid is set as a cell opening hole for starting search, and, for example, 1 row and 1 column are assigned as cell hole identification information. When defining the cell opening holes adjacent in the row direction, the centroid of the cell opening holes in the first row and the first column is used as the initial starting point, and the temporary scanning is performed in the X-axis direction of the image coordinates. Of the adjacent partition walls extending from both ends thereof, the direction along the predetermined partition wall is calculated, and this direction is set as the row direction of the cell opening hole of one row and one column, and a predetermined search area is determined based on the starting point and the row direction. The centroid coordinates closest to the starting point are obtained from the other centroid coordinates within this range, and the cell opening hole having this centroid coordinate is set as the adjacent cell opening hole and assigned as 1 row and 2 columns. Next, starting from the centroid of the cell opening hole of 1 row and 2 columns, the same processing as described above is performed to define the adjacent cell opening holes and assign 1 row and 3 columns. Thereafter, the same processing is sequentially performed to perform the same row alignment. Similarly, cell opening holes adjacent in the column direction can be defined.

Hereinafter, with reference to FIGS. 3 and 4, the method for defining the adjacent cell opening holes, that is, the allocation of the matrix numbers, will be specifically described with the image G1 as an example.
The cell opening hole for starting the search in the image G1 is the cell opening hole 11 having the centroid closest to the intersection GK of the contour line G1L of the end face and the image boundary line G1X among the centroids of the cell opening hole. Assign with columns. The cell opening hole to be assigned as 1 row and 2 column on the right is the search area E1 (with hatching A within the dotted line) set to extend in the row direction 11g with the centroid 11z of the cell opening hole 11 as the first starting point. Among the centroid coordinates in (shown), the cell opening hole 12 having the nearest centroid coordinates. The row direction 11g of the cell opening hole 11 is provisionally scanned from the centroid 11z in the X-axis direction of the image coordinates, and is along the upper partition wall, for example, of the adjacent partition walls extending from both ends with respect to the partition wall surface that first intersects. However, since the cell opening hole in this example is a square, the direction is perpendicular to the partition wall surface that first intersects.

Next, starting from the centroid 12z of the cell opening hole 12, the direction perpendicular to the partition wall surface that intersects first is obtained by provisional scanning in the row direction 11g of the cell opening hole 11, and this direction is the row of the cell processing hole 12 When the direction 12g is set and processing similar to the above is performed, the cell opening 13 is searched and becomes one row and three columns. By sequentially performing this process, a cell opening hole connected to the first row in the image is searched, and consecutive column numbers are assigned.
In the search area E1 shown in FIG. 4, the longitudinal direction is 1.5 times the designed cell opening hole interval, and the short direction is 1 time the cell opening hole interval, and the search area E1 is short around the centroid. Even if the cell opening hole shape is distorted or misplaced, the range can be set so that the adjacent cell opening hole can be searched if it is within the allowable range. Good.

  Subsequently, in order to assign the cell opening hole numbers to all the columns in the second row, the first starting point in the second row is obtained. Since the second row in this image is located above the first row, the first starting point of the second row is to search for a cell opening hole adjacent upward in the column direction from the cell opening hole 11 in the first row and the first column. Ask. That is, starting from the centroid 11z of the cell opening hole 11 of 1 row and 1 column, the upward direction orthogonal to the row direction 11g is the column direction 11r, and the search area E2 in the same range as the above-described row direction is set. This is done by setting the longitudinal direction to extend in the column direction 11r (indicated by hatching B within the dotted line) and extracting the centroid coordinates in this. In FIG. 4, the centroid 21z of the cell opening hole 21 corresponds to this, the first starting point of the second row is determined, and the cell opening hole 21 is defined as a cell opening hole adjacent to the cell opening hole 11 in the column direction. And 2 rows and 1 column are assigned as identification information.

Subsequently, starting from the centroid 21z of the cell opening hole 21, the search area E1 is set in the row direction 21g of the cell opening hole 21 obtained in the same manner as described above, the centroid coordinates in the cell opening hole 21 are obtained, and the cell The opening hole 22 is defined, and 2 rows and 2 columns are allocated. In this way, column numbers are sequentially assigned to the cell opening holes in the second row.
If there is no centroid coordinate of the cell opening hole in the set search area E2, the starting point of the second row is the cell opening hole of the first row and the second column that is right next to the starting point of the first row. It is obtained by setting the search area E2 from 12 centroids in the same manner as described above. The cell opening hole having the start point of the second row obtained in this case is assigned as 2 rows and 2 columns.

  As described above, the matrix numbers are assigned to all the cell opening holes above the cell opening holes in the first row. However, depending on the rotational direction setting posture of the honeycomb structure 1, the row direction is inclined with respect to the image coordinate axis. The cell opening hole below the cell opening hole in the first row may be unassigned. In this case, a matrix number assigning process is subsequently performed below the cell opening hole in the first row, and the matrix number may be appropriately corrected so that the matrix number is represented by a series of numbers. In this way, row and column numbers are assigned to all the cell opening holes in the image G1.

On the other hand, the control device 4 obtains the centroid coordinates (position information) of each cell opening hole with reference to an arbitrary cell opening hole of the image G1, for example, a cell opening hole whose matrix number is 1 row and 1 column, As shown in FIG. 8A, the data is stored in the memory in a matrix-like data structure in which the centroid coordinates depend on the matrix numbers of the given cell opening holes. Here, in the data of the image G1 shown in FIG. 8, the horizontal axis indicates the column number of the cell opening hole, and the vertical axis indicates the row number. The symbol in the cell of the matrix indicates the centroid coordinates of the cell opening hole. For example, “1P _(1,1) ” is the cell opening hole in which “1” before “P” is the image G “1”. This indicates that “(1, 1)” after “P” is the centroid coordinate of matrix number 1 row 1 column. The symbol “-” displayed in the cell of the matrix indicates a state in which no centroid coordinates are stored (so-called null). Needless to say, the centroid coordinates indicate the position of the centroid in the X and Y planes, and are composed of two pieces of data, the X axis component and the Y axis component.

  The control device 4 assigns a matrix number to all the cell opening holes of the captured images G2, G3, and G4, obtains centroid coordinates thereof, and similarly, as illustrated as data of the image G3 in FIG. 8B. Stored in the memory with a simple data structure. As the position information of the cell opening hole, the barycentric coordinates or the coordinates of a predetermined corner of the cell opening hole may be used. In addition, it is desirable that the matrix number is set so that the ascending order of the numbers is the same in the image coordinates even in the same image and in different images.

  As described above, the matrix numbers assigned to the cell opening holes and the obtained centroid coordinates for each of the images G1, G2, G3, and G4 are stored in the memory, and then each image is picked up based on the position of the predetermined image. At this time, the centroid coordinates of the cell opening holes of each image are converted based on the amount of movement of the XY table 2. Specifically, for example, when the image G2 is imaged by moving the image G2 by −50 mm in the X axis direction with respect to the image G1, the centroid coordinates of the cell opening hole obtained in the image G2 are added to the X axis component by 50 mm. Converted into a thing. Similarly, when the image G3 is imaged by moving the image G3 by moving 50 mm in the Y-axis direction with respect to the image G1, the centroid coordinates of each cell opening hole obtained in the image G3 are converted to those obtained by dividing the Y-axis component by 50 mm. .

  Next, as shown in S4, the control device 4 unifies the matrix numbers assigned to the images G1, G2, G3, and G4 based on the centroid coordinates (position information) on the end face of the honeycomb structure 1. Are reassigned so that the matrix number becomes That is, as described above, each image is captured so that adjacent areas partially overlap and the same cell opening hole is always shared in the overlapping part. Therefore, first, an arbitrary cell opening hole is selected from one cell opening hole of the image that is shared and imaged, and the cell opening hole of the other image having the centroid coordinates substantially coincident with the centroid coordinates of the cell opening hole. To find the matrix number. Next, a correction formula is calculated in which the matrix number of the cell opening hole selected in one image is the same as the matrix number of the cell opening hole of the other image in which the centroid coordinates coincide with each other. The matrix number of the cell opening hole in the image is corrected and reassigned to the matrix number unified as the entire end face.

The above operation will be described in detail using the data of the images G1 and G3 shown in FIG. 8 as an example.
The control device 4 selects a predetermined cell opening hole, here a cell opening hole of one row and one column from the data of the image G1 as shown in FIG. 8A, and the centroid coordinates 1P _{(1, 1)} and A cell opening hole having substantially the same centroid coordinates is searched from the data of the image G3 shown in FIG. It is assumed that the matrix number in the searched cell opening hole image G3 is 11 rows and 1 column. Next, a correction formula for reassigning the matrix number of the image G1 with the matrix number of the image G3 as a reference is calculated, and the matrix number of the cell opening hole of the image G1 is corrected by the correction formula as shown in FIG. 8C. Then, the matrix numbers are reassigned to the images G1 and G3. In this example, the matrix number of the cell opening hole with the coincident centroid coordinates is 1 row and 1 column in the image G1, and 11 rows and 1 column in the image G3, so (the row number of the corrected image G1 = −1 ×). A correction formula for correcting only the line number of the image G1 (line number + 12) is calculated. If the same processing is also applied to the images G2 and G4, the continuous row and column numbers can be assigned to all the cell opening holes formed on the entire end face of the honeycomb structure 1 without overlapping. Note that an image serving as a reference for unifying matrix numbers may be selected as appropriate.

Next, a method for defining the cell opening hole to be plugged shown in S5 of the flowchart of FIG. 2 will be described.
As described above, since one of the set cell opening holes to be plugged is marked, this marking is recognized by the image processing at the time of imaging, and the matrix number assigned to this cell opening hole is obtained. . Based on this matrix number, other cell opening holes to be plugged can be obtained by simple numerical calculation and can be defined in a very short time. That is, to plug in a checkered pattern, when the value of the row and column number of the cell opening hole in the marking part is an even number, the value of the other cell opening hole to be plugged is the value of the row and column number added. Is an even cell opening hole. When the value obtained by adding the row and column number of the cell opening hole of the marking portion is an odd number, the cell opening hole is a value obtained by adding the row and column number to an odd number. The same applies when the column number is subtracted from the row number. Also, the centroid coordinates of the cell opening holes in each image are obtained, and the coordinate position relationship of each image can be obtained from the amount of movement of the XY stage. The control device 4 can be uniquely determined by an arbitrarily set CCD camera coordinate system, and the coordinate information indicating the centroid and shape of the cell opening hole to be plugged obtained above is linked with the matrix number. Can be remembered.

  As described above, the matrix number in the present invention is continuous numerical data, and not only functions as identification information that can define the cell opening hole to be plugged by arithmetic calculation, but also in the end face of the honeycomb structure. Can be used as address information, and the approximate position of the cell opening hole can be known, which is suitable when the sheet is removed by dividing the end face into a plurality of places as will be described later. Further, various data such as the position and shape of each cell opening hole can be used as a management label when computer processing is performed.

As described above, the example using the matrix number as the cell hole identification information for identifying whether the hole is to be plugged or not to be plugged is described. The cell hole identification information having data may be used to alternately give data for plugging holes and data for non-plugging holes to adjacent cell opening holes. As the data, for example, “1” and “0” may be used so as to facilitate computer processing. In this case, from the beginning, the hole to be plugged is set to 1 and the hole not to be plugged is set to 0. After tentatively allocating all the cell opening holes, the data assigned to the reference hole is referred to. For example, the information given to each cell opening hole may be held as it is, and if it is 0, the data may be inverted and held, or initially, the data assigned to the reference hole is simply assigned 1 or 0. The cell opening hole assigned with the same numerical value as that data may be defined as a hole to be plugged.
Note that this description has been made in the case where the end face is imaged with four visual fields, but it goes without saying that the present invention can also be applied to an image captured with one visual field. In addition, when the cell opening hole is formed exactly as shown in the design drawing and the rotation direction is positioned so that the cell opening hole is in a certain direction, the adjacent cell opening hole has the coordinate information calculated by image processing. Even if it is not obtained from the original, it can also be obtained from the coordinate information obtained from the design drawing.

Next, the sheet removal method will be described.
When the cell opening hole to be plugged is selected, the movement of the XY stage 2 is controlled so that the honeycomb structure 1 comes below the laser head 5. As described above, in order to remove a predetermined portion of a sheet with good accuracy using an optical deflection laser processing machine, it is important to set a range in which the fluctuation width of the light beam is small as a processing area. For example, in an experiment using a laser processing machine having a processing range of 100 mm square on one side, the cell opening hole located at a position exceeding 70 mm square has a remarkable shift of the melting center with respect to the centroid, resulting in poor sheet removal accuracy. It has been confirmed that the processing area is preferably 70 mm square or less, and more preferably 50 mm square or less. Therefore, when the size of the end face is larger than the set processing area, the honeycomb structure 1 is moved so as to divide the end face into a plurality of processing areas and processed each time. Note that the coordinate information in the laser head coordinate system is obtained by converting the coordinate information of the cell opening hole in the CCD camera coordinate system obtained above because the mechanical contact dimensions of the CCD camera 3 and the laser head 5 are determined. The laser head 5 performs processing based on the coordinate information.

  In the following description, it is assumed that the end face is divided into four as shown in FIG. In this case, in the CCD camera coordinate system set for the entire end face, the outline lines 66, 67, 68, 69 constituting the rectangular area circumscribing the end face, and the intermediate line 70 that bisects the rectangular area vertically and horizontally, 71 is calculated, and the end surface is divided into four rectangular areas L1, L2, L3, and L4 divided by these line segments to make each rectangular area a machining area, and the machining center in the machining area is the diagonal line of each machining area The intersection points 61, 62, 63, and 64 may be used. This is because the intersection positions are equidistant from the four corner edges of the processing area. In addition, what is necessary is just to determine beforehand in which process area about the cell process hole in the boundary vicinity of each process area. At this time, if the cell opening holes included in each processing area are managed by the matrix number, the cell opening holes near the boundary can be easily extracted by the matrix number.

  Sheet removal processing is performed by moving the XY stage 2 so that the intersections 61, 62, 63, 64 come to the center of the processing range of the laser head 5. For example, when the center of the processing range of the laser head 5 is at the intersection 61, sheet removal processing is performed on the cell opening hole in the processing area L3 at the lower left of the end face shown in FIG. The XY stage 2 is moved so that the center of the processing range of the head 5 comes to the intersection 62, and sheet removal processing is performed on the cell opening hole in the lower right processing area L4. The sheet processing order in the processing area may be performed in the order of the matrix number defined as the opening hole to be plugged according to the matrix number assigned to the cell opening hole, or the coordinate value of the centroid according to the XY axis direction of the coordinate system You may make it carry out in order.

  In removing the sheet, it is desirable to irradiate the laser beam along the cell partition wall so as not to leave the sheet in the opening of the cell opening hole as much as possible. The ratio of the removal area to the cell opening hole area varies depending on the cell opening hole area and the viscosity of the sealing material used, but is preferably 50% or more, and more preferably 80% or more. In addition, it is preferable that a laser beam is not irradiated to a partition wall, and about 90% is an upper limit at this point. That is, in the case of a square cell opening hole with a side of 1 mm in this example, a pattern in which a side is a square with a side of about 0.7 to 0.9 mm centered on the centroid position obtained by image processing of the cell opening hole. It is good to irradiate with. However, since the large honeycomb structure is easily distorted and the cell opening holes are easily deformed as described above, there is a possibility that the seal remains locally or the partition wall is irradiated with the laser beam and damaged. For this reason, as shown in S7, the degree of deformation of the cell opening hole to be removed is determined, and the laser light irradiation method is switched based on this result. The degree of deformation may be determined by comparing the area of the cell opening hole, the side length, the diagonal length, and the like with respect to the design value and the value obtained by image processing.

  For example, as shown in FIG. 6, the formed cell opening hole 51 (shown by a solid line) is greatly deformed into a parallelogram shape with respect to the cell opening hole 52 having a square design shape (shown by a dotted line). In such a case, in the pattern irradiation method described above, the opening hole corners 53 and 54 may remain blocked because the sheet cannot be removed, which may cause plugging failure. Therefore, if it is determined in S6 of the flowchart of FIG. 2 that the deformation is small, the pattern irradiation method centered on the centroid position obtained by the image processing of the cell opening hole described above may be used, but it is determined that the deformation is large. Then, the process proceeds to S7, and as shown in FIG. 6B, based on the coordinate data of the cell opening hole edge portions 55, 56, 57, and 58 obtained by the image processing, the coordinate point slightly inside the edge portion. Position control data is created, the laser beam is scanned along the wall surface of the deformed cell opening hole, the laser beam is irradiated to the locus corresponding to the deformed shape, and the sheet is removed.

  As described above, when the sheet removal processing is completed for the cell opening holes formed on one end face and numbered by the matrix, the honeycomb structure 1 is removed from the XY stage 2 and the sheet is already pasted on the other end face. In such a case, the cell opening hole is set in an inverted manner, and the cell opening hole to be plugged is selected in the same manner as described above, and the sheet covering the cell opening hole is removed. If the sheet is not affixed to the other end surface, the sheet is affixed in the sheet coating process, marked on one of the cell opening holes to be plugged, and then set on the XY stage with the other end side facing up The same processing as described above is performed. Thereafter, the honeycomb structure is sent to a plugging process, where plugging is performed.

  As described above, the present invention has been described with the system configuration in which the honeycomb structure is set on the XY stage, the XY stage is moved and controlled, the cell opening hole to be plugged is selected, and then the sheet is removed. The configuration is not limited. When the honeycomb structure is set on the XYθ stage and the image is taken with a CCD camera, the rotational direction of the honeycomb structure is controlled so that the approximate arrangement of the cell opening holes is aligned with the X or Y direction of the image. Matrix number assignment can be performed simply. In addition, a jig configured according to the production volume, production efficiency, etc., for example, a means for selecting a cell opening hole to be plugged and a sheet removing means can be operated independently, and a honeycomb structure is set between them. However, the present invention can also be applied to a system configuration in which necessary data is transferred while being exchanged.

In addition, the shape of the cell opening hole is not limited to a square, and may be any shape such as a rectangle, a parallelogram, a rhombus, etc. formed by dividing a substantially lattice-shaped partition wall. Even a triangular shape formed by dividing into two or a circular shape divided by a lattice-like partition wall can be dealt with appropriately.
In addition, the laser processing method may be a method in which spot light is sequentially irradiated instead of the continuous light method depending on the size of the cell opening hole, the intensity of the laser light, and the like. Further, when the area of the cell opening hole is extremely small or the shape is close to a circle, it can be dealt with by simply irradiating the centroid with laser light. Note that the type of laser light may be appropriately selected from CO ₂ and YAG according to the sheet material to be used.

  The present invention can be applied not only to a honeycomb structure but also to a field in which, for example, the end surface of a workpiece having a hole with a closed end surface is selectively removed and opened.

It is a figure which shows an example of the system configuration which implements this invention. It is a flowchart which shows the outline | summary of this invention. It is a figure which shows the picked-up image when a honeycomb structure end surface is divided into four. It is a figure for demonstrating the method to prescribe | regulate a row direction and a column direction. It is a figure for demonstrating the method of integrating 4 images and unifying a matrix number and allocating. It is a figure for demonstrating the difference of the sheet | seat removal method with respect to the deformed cell opening hole. It is a figure for demonstrating that a honeycomb structure end surface is divided into 4 and laser processing is performed. It is a figure which shows the data structure of the matrix number allocated to the cell opening hole stored in the memory of the control apparatus of FIG. 1, and its centroid coordinate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Honeycomb structure 2 XY stage 3 CCD camera 4 Control apparatus 5 Laser head G1, G2, G3, G4 Image of end face 11, 12, 13, 21, 22 Cell opening hole 11z, 12z, 21z Diagram of each cell opening hole Core 11g, 12g, 21g Row direction of each cell opening E1 Row direction search area E2 Column direction search area L1, L2, L3, L4 Laser processing area of end face

Claims (1)

  In a plugging method for a honeycomb filter, in which a plurality of cells extending in the axial direction are plugged into a cell opening hole of a honeycomb structure, the end face of the honeycomb structure is divided into a plurality of areas so that the same cell opening hole as an adjacent area is formed. Images are taken to be shared, and for each captured image, adjacent cell opening holes are sequentially obtained according to the adjacent cell search rule based on the graphic information of the cell opening holes calculated by image processing based on a predetermined cell opening hole. Cell hole identification information for identifying whether to make a plugging hole or a plugging unnecessary hole to the cell opening hole to be assigned, cell hole identification information of the cell opening hole uniquely assigned to each captured image, A honeycomb filter characterized by reassigning cell hole identification information unified over the entire end face based on position information of the cell opening holes shared and imaged, and selecting cell opening holes to be plugged I plugged methods.

Images