Machining method for cutting blades

Abstract

To improve the efficiency of using dressing boards in the machining of cutting blades. [Solution] The cutting blade (11) and the dress board (30) are moved relative to each other along a first direction (Y) along the first surface (301) of the dress board, and a first processing step and a second processing step are performed in which the dress board is removed by the rotating cutting blade while the cutting blade is processed by the dress board. Between the first processing step and the second processing step, the cutting blade and the dress board are moved relative to each other along a second direction (X) along the first surface, and in the first and second processing steps, the shape of the area of ​​the dress board removed by the cutting blade is made asymmetrical with respect to the perpendicular line (Q) connecting the point (P) where the surface of the cutting blade and the axis of rotation intersect when viewed from the first direction and the first surface of the dress board.

Description

【Technical Field】 【0001】 The present invention relates to a method for processing a cutting blade. 【Background Art】 【0002】 In a cutting apparatus for processing a workpiece, a cutting blade, which is a rotating processing tool, is consumed as it is used. Therefore, shape correction for adjusting the tip shape of the cutting edge of the cutting blade is periodically performed. For example, as an example of shape correction, as disclosed in Patent Document 1 and Patent Document 2, flat dressing for flattening the tip shape of the cutting edge of the cutting blade along the rotational axis direction of the cutting blade is performed. 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Unexamined Patent Application Publication No. 2016-203352 【Patent Document 2】 Japanese Patent No. 7386636 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 The flat dressing mechanism in a cutting machine includes a plate-shaped dressing board. At the height position where the cutting blade cuts into the dressing board, the cutting blade and the dressing board are moved relative to each other in the direction of the cutting blade's rotation axis. This process removes material from the dressing board with the rotating cutting blade, while flattening the tip shape of the cutting blade. When this process is performed, a groove-shaped machining mark with an inverted arc-shaped cross-section corresponding to the tip (outer edge) shape of the cutting blade is formed along the machining path in which the cutting blade and the dressing board are moved relative to each other in the direction of the cutting blade's rotation axis. More specifically, multiple machining passes are performed along the rotation axis of the cutting blade on the same line of the dressing board, and the depth of cut by the cutting blade from the top surface of the dressing board is increased with each machining pass on the same line. Once the cutting blade reaches a certain depth of cut on one line, the cutting blade is moved to the next (unmachined) line of the dressing board, and similarly, multiple machining passes are performed with different depths of cut. By repeatedly performing this type of machining, multiple machining marks are formed on the dressing board, each extending in the direction of the cutting blade's rotation axis (each machining mark is a trace of the rotating cutting blade moving multiple times on the same line at different cutting depths). Conventionally, machining was performed so that the multiple machining marks formed on the dressing board were spaced apart from each other in a direction intersecting the cutting blade's rotation axis. However, this conventional machining method had the problem of limiting the number of machining paths that could be set on the dressing board, increasing the frequency of dressing board replacement, and making it difficult to effectively utilize the dressing board. [Means for solving the problem] 【0005】 One aspect of the present disclosure is a method for processing a cutting blade using a plate-shaped dress board, comprising: a holding step of holding the second surface of the dress board, which is located opposite in the thickness direction to the first surface of the dress board into which the cutting blade is cut, with a holding table; a first positioning step of positioning the cutting blade, which rotates around a rotation axis, and the dress board held on the holding table, in a first positional relationship in which the cutting blade and the dress board overlap when viewed from a first direction along the first surface; a first processing step of moving the cutting blade and the dress board, which are positioned in the first positional relationship in the first positioning step, relatively along the first direction, and processing the cutting blade with the dress board while removing the dress board with the rotating cutting blade; and after the first processing step, the cutting blade and the dress board The invention provides a cutting blade and a dress board, which are moved relative to each other along a second direction that intersects the first direction and lies along the first surface, and are positioned in a second positional relationship where the cutting blade and the dress board, which are held on the holding table, overlap when viewed from the first direction; and a second processing step in which the cutting blade and the dress board, which are positioned in the second positional relationship in the second positioning step, are moved relative to each other along the first direction, and the cutting blade is processed by the dress board while the dress board is removed by the rotating cutting blade, wherein in the first processing step and the second processing step, the shape of the area of ​​the dress board removed by the cutting blade is asymmetric with respect to the perpendicular line connecting the point where the surface of the cutting blade and the axis of rotation intersect when viewed from the first direction and the first surface of the dress board. 【0006】 Preferably, the relative distance of movement along the second direction in the second positioning step is smaller than the radius of the cutting blade. 【0007】 Preferably, the processing marks removed from the dress board by the first and second processing steps include surfaces along the first surface with a height of 200 μm or less of unevenness. 【0008】 One aspect of the present disclosure is a method for processing a cutting blade using a plate-shaped dress board, comprising: a holding step of holding the side of the dress board opposite in the thickness direction to the first surface of the dress board into which the cutting blade is cut with the side of the dress board opposite in the thickness direction with the holding table; a positioning step of positioning the cutting blade, which rotates around a rotation axis, and the dress board held on the holding table, such that the cutting blade and the dress board overlap when viewed from a first direction along the first surface; and after the positioning step, moving the cutting blade and the dress board relative to each other along the first direction and rotating the cutting blade The process includes a machining step of removing the dress board with a cutting blade while machining the cutting blade with the dress board, and a height correction step of moving the cutting blade and the dress board relative to each other along a third direction intersecting the first surface of the dress board before performing the next machining step after the positioning step and the machining step have been repeated multiple times, wherein the shape of the area of ​​the dress board removed by the cutting blade in the machining step is asymmetric with respect to the perpendicular line connecting the point where the surface of the cutting blade and the axis of rotation intersect and the first surface of the dress board when viewed from the first direction. [Effects of the Invention] 【0009】 According to the cutting blade processing methods of each of the above embodiments, the utilization efficiency of the dress board can be improved. [Brief explanation of the drawing] 【0010】 [Figure 1] This is a perspective view of a cutting machine. [Figure 2] This is a perspective view showing the cutting mechanism and dressing board unit. [Figure 3] This figure shows the dress board unit in a state where it is held on a holding table (holding process). [Figure 4] This figure shows the case where a cutting blade is processed using the comparative example processing method. [Figure 5] This is a diagram illustrating the first positioning process. [Figure 6] This is a diagram illustrating the first processing step. [Figure 7] This is a diagram illustrating the second positioning process. [Figure 8] This is a diagram illustrating the second processing step. [Figure 9] This diagram shows the dress board after the first layer of processing has been completed. [Figure 10] This diagram shows the process of applying the second layer of processing to the dress board. [Figure 11] This figure shows a first modified example of the machining method for cutting blades. [Figure 12] This figure shows a second modified example of the cutting blade processing method. [Figure 13] This figure shows a third modified example of the cutting blade processing method. [Figure 14] This figure shows a fourth modified example of the cutting blade processing method. [Modes for carrying out the invention] 【0011】 The cutting device 10 shown in Figure 1 is a processing device that performs cutting on a workpiece 1 using a cutting blade 11, which is a processing tool. The X-axis, Y-axis, and Z-axis directions shown in each drawing are perpendicular to each other, and the Z-axis direction is the vertical direction of the cutting device 10. The Y-axis direction is the first direction in this disclosure, the X-axis direction is the second direction in this disclosure, and the Z-axis direction is the third direction in this disclosure. 【0012】 The workpiece 1 is, for example, a semiconductor wafer in which semiconductor chips are formed in a plurality of device regions partitioned by division planned lines. The cutting device 10 performs cutting on the workpiece 1 along the division planned line by a rotating cutting blade 11. Note that the processing by the cutting device 10 is not limited to such a case. For example, the cutting device 10 may perform edge trimming to remove a chamfer formed on the outer periphery of the disk-shaped workpiece 1 by cutting with the cutting blade 11. Further, the workpiece 1 is not limited to a semiconductor wafer, and may be an optical device wafer in which an optical device is formed on an inorganic material substrate such as ceramic, glass, or sapphire. 【0013】 A flexible tape 2 is attached to the workpiece 1, and the workpiece 1 is supported via the tape 2 inside the opening of a ring-shaped ring frame 3. In a state of a workpiece unit 4 constituted by the workpiece 1, the tape 2, and the ring frame 3, it is conveyed to the cutting device 10. 【0014】 A holding table 13 for holding the workpiece unit 4 is provided on a base 12 of the cutting device 10. The holding table 13 has an upward holding surface 131 on which the workpiece 1 is placed. The holding surface 131 is formed by a porous member connected to a suction source 14 (FIG. 3), and the suction source can be operated to apply a suction force to the holding surface 131. A plurality of clamp portions 132 for holding the ring frame 3 are provided on the outer peripheral portion of the holding table 13. The holding table 13 is rotated about an axis in the Z-axis direction by a table rotation mechanism 15 provided with a motor. 【0015】 On the base 12, an X-axis moving mechanism 16 for moving the holding table 13 in the X-axis direction is provided. The X-axis moving mechanism 16 includes a pair of guide rails 161 and a ball screw 162 that are attached to the base 12 and extend in the X-axis direction, a motor 163 for rotationally driving the ball screw 162, and an X-axis moving table 164 that supports the holding table 13 via the table rotation mechanism 15. When the ball screw 162 is rotated by the motor 163, the X-axis moving table 164 moves along the pair of guide rails 161, changing the position of the holding table 13 in the X-axis direction. 【0016】 On a column 17 erected on the upper surface of the base 12, a Y-axis moving mechanism 18 for moving (indexing feed) the cutting mechanism 20 having the cutting blade 11 in the Y-axis direction and a Z-axis moving mechanism 19 for moving (cutting feed) the cutting mechanism 20 in the Z-axis direction are provided. The Y-axis moving mechanism 18 includes a pair of guide rails 181 and a ball screw 182 that are attached to the column 17 and extend in the Y-axis direction, a motor 183 for rotationally driving the ball screw 182, and a Y-axis moving table 184 that supports the cutting mechanism 20 via the Z-axis moving mechanism 19. When the ball screw 182 is rotated by the motor 183, the Y-axis moving table 184 moves along the pair of guide rails 181, changing the position of the cutting mechanism 20 in the Y-axis direction. The Z-axis moving mechanism 19 includes a pair of guide rails 191 and a ball screw 192 that are attached to the Y-axis moving table 184 and extend in the Z-axis direction, a motor 193 for rotationally driving the ball screw 192, and a Z-axis moving table 194 that supports the cutting mechanism 20. When the ball screw 192 is rotated by the motor 193, the Z-axis moving table 194 moves along the pair of guide rails 191, changing the position of the cutting mechanism 20 in the Z-axis direction. The cutting mechanism 20 is supported at the lower end of the Z-axis moving table 194 that constitutes the Z-axis moving mechanism 19. 【0017】 As shown in Figures 2 and 3, the cutting mechanism 20 comprises a spindle 21, which is a rotating shaft extending in the Y-axis direction, and a spindle housing 22 that houses the spindle 21. A cutting blade 11 is mounted on the tip of the spindle 21 that protrudes from the spindle housing 22. The cutting blade 11 rotates around the axis C of the spindle 21 by the driving force of a spindle motor (not shown) inside the spindle housing 22. 【0018】 As shown in Figure 3, an annular mount 23, which is coaxial with the spindle 21 and has a larger diameter than the spindle 21, is provided on the tip side of the spindle 21. The cutting blade 11 has an annular hub 24 facing the mount 23 and an annular cutting edge 25 located on the outer edge of the hub 24. The cutting edge 25 protrudes outward from the outer edge of the hub 24. The tip of the spindle 21 is inserted through the circular mounting hole in the center of the hub 24, and the cutting blade 11 is inserted until the cutting edge 25 is sandwiched between the mount 23 and the hub 24. The cutting blade 11 is then fixed to the spindle 21 and the mount 23 by screwing a nut 26 onto the male thread on the tip of the spindle 21 protruding from the mounting hole and tightening it. Note that the cutting blade 11 may also be a hubless type cutting blade in which the annular cutting edge is separate from the hub. 【0019】 An imaging unit 27 is mounted on the spindle housing 22. The imaging unit 27, together with the cutting mechanism 20, is moved in the Y-axis direction by the Y-axis movement mechanism 18 and in the Z-axis direction by the Z-axis movement mechanism 19. The imaging unit 27 is capable of imaging downwards in the Z-axis direction. 【0020】 The control unit 28 of the cutting device 10 controls the operation of each part of the cutting device 10 according to a control program. Specifically, the control unit 28 controls the operation of the table rotation mechanism 15, the operation of the X-axis movement mechanism 16 (driving the motor 163), the operation of the Y-axis movement mechanism 18 (driving the motor 183), the operation of the Z-axis movement mechanism 19 (driving the motor 193), and the rotation of the cutting blade 11 in the cutting mechanism 20 (driving the spindle motor). Image data captured by the imaging unit 27 is also transmitted to the control unit 28. Based on the images captured of the workpiece 1 held on the holding table 13 and the dressing board 30 described later, the control unit 28 operates the table rotation mechanism 15, X-axis movement mechanism 16, Y-axis movement mechanism 18, and Z-axis movement mechanism 19 to position the cutting blade 11 relative to the workpiece 1 and the dressing board 30. 【0021】 This section describes the process of machining a workpiece 1 using a cutting device 10 along multiple grid-like division lines extending in the X-axis and Y-axis directions. By cutting along the division lines, machining grooves such as full-cut grooves that penetrate the workpiece 1 in the thickness direction, and half-cut grooves (bottomed grooves) that are only partially deep in the thickness direction of the workpiece 1 are formed. 【0022】 A workpiece unit 4, equipped with a workpiece 1, is transported to the cutting device 10. The workpiece unit 4 is placed on the holding surface 131 of the holding table 13 with the tape 2 facing downwards, and the workpiece 1 is held on the holding table 13 via the tape 2. The ring frame 3 is also fixed by the clamp portion 132. Based on the image of the workpiece 1 held on the holding table 13 captured by the imaging unit 27, the control unit 28 adjusts the relative positions of the holding table 13 and the cutting mechanism 20 in the X-axis and Y-axis directions using the X-axis movement mechanism 16 and the Y-axis movement mechanism 18 to position the cutting blade 11 above the extension of the division line that is to be cut. Subsequently, the control unit 28 drives the spindle motor to rotate the spindle 21 and the cutting blade 11, and moves the cutting mechanism 20 downward in the Z-axis direction using the Z-axis movement mechanism 19 until it reaches a predetermined cutting depth. Then, by moving the holding table 13 in the X-axis direction using the X-axis movement mechanism 16, the cutting edge 25 of the cutting blade 11 is made to cut into the workpiece 1, and cutting is performed along the planned machining line extending in the X-axis direction. 【0023】 Once cutting along one planned machining line is completed, the control unit 28 moves the cutting mechanism 20 upward in the Z-axis direction using the Z-axis movement mechanism 19, separating the cutting blade 11 from the workpiece 1. Next, the control unit 28 moves the cutting mechanism 20 in the Y-axis direction using the Y-axis movement mechanism 18 (indexing feed), positioning the cutting blade 11 above the extension of the next uncut planned machining line. Then, similarly to the above, the cutting blade 11 is moved downward in the Z-axis direction using the Z-axis movement mechanism 19, and the holding table 13 is moved in the X-axis direction using the X-axis movement mechanism 16, performing cutting along the planned machining line. 【0024】 Once cutting is complete along all the planned machining lines aligned in the Y-axis direction, the control unit 28 rotates the holding table 13 by 90 degrees using the table rotation mechanism 15. As a result, the workpiece 1 on the holding table 13 is positioned so that multiple uncut planned machining lines are aligned in the Y-axis direction (extending toward the X-axis direction). Then, cutting is performed sequentially along all the uncut planned machining lines in the same manner as described above. 【0025】 In the cutting device 10, the cutting blade 11 is processed to restore the shape of the cutting edge 25 of the cutting blade 11, which has been worn down by the cutting process. For example, using the dressing board 30 shown in Figure 2, a flat dressing process is performed to flatten the tip shape of the cutting edge 25 along the Y-axis direction, which is the rotation axis direction of the cutting blade 11. 【0026】 As shown in Figure 2, the dress board 30 is attached to the inside of the opening of a ring frame 32, which has a similar configuration to the ring frame 3 in the workpiece unit 4 described above, via a flexible tape 31. The dress board unit 33, consisting of the dress board 30, tape 31, and ring frame 32, is then transported to the cutting device 10. The dress board 30 is formed by solidifying abrasive grains, such as green carbide (GC) or white alundum (WA) with a bonding agent such as resin bond. The dress board 30 has two parallel planes, a first surface 301 and a second surface 302, in the thickness direction, and is formed into a plate shape with a substantially uniform thickness, to which the tape 31 is attached. The dress board 30 is a rectangular plate shape that fits inside the opening of the ring frame 32. However, the shape of the dress board 30 is not limited to a rectangle. 【0027】 The cutting blade 11 is processed using the dressing board 30 (flat dressing) at predetermined intervals. For example, flat dressing is performed periodically after processing a predetermined number of workpieces 1. Alternatively, flat dressing may be performed at any time at the instruction of the operator operating the cutting device 10. In either case, at least the positioning step and the processing step of the processing method of this disclosure described below are automatically executed by the control unit 28. 【0028】 The flattening of the cutting blade 11 is performed by cutting the dressing board 30 with the cutting blade 11 rotating around the spindle 21 as its axis of rotation. Specifically, the cutting blade 11 and the dressing board 30 are moved relative to each other in the Y-axis direction (first direction), which is the axis of rotation of the cutting blade 11 (the direction in which the axis C of the spindle 21 extends), by the Y-axis movement mechanism 18. As the dressing board 30 is removed by the rotating cutting blade 11, the cutting blade 11 is processed by the dressing board 30, thereby flattening the tip shape of the cutting edge 25. The movement trajectory of the cutting blade 11 on the dressing board 30 due to this relative movement in the Y-axis direction is defined as the machining path. Furthermore, the trace left on the dressing board 30 after the cutting blade 11 has removed the dressing board 30 while passing through the machining path is defined as the machining mark. In the cutting device 10, the cutting blade 11 is moved along multiple machining paths positioned differently in the X-axis direction (second direction) relative to the dress board 30, thereby forming multiple machining marks on the first surface 301 of the dress board 30. Unlike when machining the workpiece 1, when machining the dress board 30 with the cutting blade 11, the Y-axis direction is the machining feed direction along the machining path, and the X-axis direction is the indexing feed direction intersecting the machining path. 【0029】 As the dressing board 30 is continuously used in the flat dressing process, multiple machining marks are formed on the first surface 301, with positions differing in the X-axis direction and extending in the Y-axis direction. Depending on the state of the cutting edge 25 of the cutting blade 11, the number of machining passes required to complete the flat dressing with a single cutting blade 11 varies. For example, machining with a single cutting blade 11 may be completed in a single machining pass, or it may be necessary to machine a single cutting blade 11 across multiple machining passes. In addition, the flat dressing of the cutting blade 11 may be completed (the tip shape of the cutting edge 25 may be sufficiently refined) midway through a single machining pass. 【0030】 In this embodiment, the cutting apparatus 10 is structured to move the cutting mechanism 20, which includes the cutting blade 11, in the Y-axis direction during the flat dressing process. However, the holding table 13 that holds the dress board 30 may move in the Y-axis direction instead of the cutting mechanism 20, or both the cutting mechanism 20 and the holding table 13 may move in the Y-axis direction. Furthermore, in this embodiment, the cutting apparatus 10 is structured to move the holding table 13 that holds the dress board 30 in the X-axis direction. However, the cutting mechanism 20 may move in the X-axis direction instead of the holding table 13, or both the cutting mechanism 20 and the holding table 13 may move in the X-axis direction. 【0031】 Figure 4 shows the case where the cutting blade 11 is processed using a comparative example processing method different from the processing method of this disclosure. In this comparative example, the rotating cutting blade 11 is driven into the first surface 301 of the dress board 30 to a predetermined depth in the Z-axis direction, and the cutting blade 11 and the dress board 30 are moved relative to each other in the Y-axis direction (first direction) to form a processing mark Sv with an inverted arc-shaped cross-section. This process is performed multiple times at different positions in the X-axis direction (second direction). Specifically, along a single processing line extending in the Y-axis direction (first direction), the cutting blade 11 driven into the dress board 30 is rotated and moved in the Y-axis direction repeatedly to perform processing multiple times (multiple processing passes) on the same processing line. At that time, as the number of processing times on the same processing line increases, the depth of the cut by the cutting blade 11 from the first surface 301 is increased. The processing mark Sv shown in Figure 4 is the trace formed by performing processing (removal of the dress board 30) multiple times with different depths of cut along a single processing line. When the machining mark Sv reaches a predetermined depth from the first surface 301, the cutting blade 11 and the dress board 30 are moved relative to each other in the X-axis direction (second direction) to position the cutting blade 11 on the next (unmachined) machining line. Then, along this new machining line, machining is performed multiple times (multiple machining passes) in the Y-axis direction as described above, and as a result, the machining mark Sv is formed. The relative movement of the cutting blade 11 and the dress board 30 in the X-axis direction (second direction) when moving from one machining line to the next is set so that two adjacent machining marks Sv in the X-axis direction do not overlap and maintain independent shapes, and the first surface 301 of the dress board 30 remains between the two machining marks Sv. 【0032】 In the machining method of this comparative example, machining must be performed along the next machining line while avoiding machining marks Sv formed along the previous machining line. As a result, the spacing between multiple machining marks Sv in the X-axis direction becomes wider, and there is a problem that the number of machining passes that can be machined on the dressing board 30 is limited. Furthermore, as shown in Figure 4, when multiple machining marks Sv are intermittently formed in the X-axis direction on the side of the first surface 301 of the dressing board 30, the height difference between the concave shape caused by these machining marks Sv and the convex shape where the first surface 301 remains becomes large, resulting in a low degree of flatness. This makes the shape unsuitable for further flat dressing of the cutting blade 11, and the dressing board 30 may be discarded even when a large amount of thickness remains. Thus, the machining method of the comparative example has the problem that the dressing board 30 cannot be fully utilized. 【0033】 Furthermore, as shown in Figure 4, in the comparative example's machining method, when machining (removing the dress board 30) is performed multiple times along the same machining line from the first surface 301 of the dress board 30 at different cutting depths in the Z-axis direction to form a machining mark Sv, the cutting width in the X-axis direction of the cutting blade 11 on the first surface 301 of the dress board 30 differs depending on the difference in the cutting position of the cutting blade 11 in the Z-axis direction in each machining operation. If the amount of cutting Zv of the cutting blade 11 in the Z-axis direction is constant, the cutting width Wa in the X-axis direction becomes larger when the cutting blade 11 is in a shallow position close to the first surface 301, and the cutting width Wb in the X-axis direction becomes smaller when the cutting blade 11 is in a deep position far from the first surface 301. Therefore, if machining is attempted under conditions where the cutting position of the cutting blade 11 in the Z-axis direction differs from that of the dress board 30, the machining conditions such as the cutting width in the X-axis direction will differ in each machining operation, making it difficult to precisely control the finishing accuracy and timing of the flat dressing process of the cutting blade 11. Furthermore, if the cutting width in the X-axis direction differs for each machining pass, it becomes difficult to position the machining lines such that the machining marks Sv formed on the later machining line avoid the machining marks Sv formed on the previous machining line, thus complicating the control of the positioning of the cutting blade 11 in flat dressing. Thus, the machining method of the comparative example has issues in terms of the high machining accuracy of the cutting blade 11 and the ease of machining control. 【0034】 A machining method for the cutting blade of this disclosure, which differs from the machining methods of the comparative examples described above, is described below. In the drawings from Figure 4 onward, the cutting blade 11 is simplified and shown as a simple disc shape consisting only of the outer circumference of the cutting edge 25, and the thickness of the dressing board 30 in the Z-axis direction is exaggerated. Figures 5 to 8 (A) show the positional relationship between the cutting blade 11 and the dressing board 30 in a plan view along the Z-axis direction, and Figures 5 to 8 (B) show the positional relationship between the cutting blade 11 and the dressing board 30 in a side view along the Y-axis direction. 【0035】 In the following description, the first positioning step and the first machining step, and the second positioning step and the second machining step, refer to two machining operations (the nth and n+1th operations) along any two consecutive machining paths among multiple machining operations performed between the dress board 30 and the cutting blade 11. In other words, the first positioning step and the first machining step do not mean only the machining along the first machining path performed on the dress board 30 in its unmachined state, but rather include at least one machining operation following the first machining step. For example, prior to the first positioning step shown in Figure 5, machining along at least one machining path has already been performed, and in Figure 5, the position of the cutting blade 11 at the location where machining along the previous machining path was performed is shown by a dashed line. 【0036】 [Holding process] When performing flat dressing of the cutting blade 11, as shown in Figure 3, the dressing board unit 33 is placed on the holding surface 131 of the holding table 13 with the tape 31 facing downward in the Z-axis direction, and the second surface 302 of the dressing board 30 is held by the holding table 13 via the tape 31. The ring frame 32 is also fixed by the clamp portion 132. In this state, the cutting blade 11 can cut into the side of the dressing board 30 facing upward in the Z-axis direction, namely the first surface 301. Thus, in the holding process, the side of the dressing board 30 that is opposite in the thickness direction to the first surface 301 into which the cutting blade 11 cuts, namely the second surface 302, is held by the holding table 13. 【0037】 [First Positioning Process] As shown in Figure 5, in the first positioning step, the cutting blade 11, which rotates around the axis C of the spindle 21, and the dress board 30 held on the holding table 13 are positioned in a first positional relationship where the cutting blade 11 and the dress board 30 overlap when viewed from the Y-axis direction (the direction in which the axis C of the spindle 21 extends), which is the first direction along the first surface 301 (see in particular Figure 5(B)). Figure 5 shows the machining marks S where the cutting blade 11 has removed the dress board 30 along the previous machining path. As shown in Figure 5(B), in the first positional relationship set in the first positioning step, when viewed from the Y-axis direction, there is an overlapping region Ka enclosed by the outer edge of the cutting blade 11, the bottom surface of the previous machining marks S, and the unmachined first surface 301 of the dress board 30. Also, when viewed from the Y-axis direction, a part of the cutting blade 11 positioned in the first positioning step overlaps with a part of the previous machining marks S. 【0038】 In the first positioning step, the positioning to the first positional relationship is performed by the control unit 28 operating the X-axis movement mechanism 16, the Y-axis movement mechanism 18, and the Z-axis movement mechanism 19 by referring to the image of the dress board 30 captured by the imaging unit 27. As shown in Figure 5(A), in the first positioning step, in the Y-axis direction, the cutting blade 11 is outside the range of the dress board 30, and the cutting blade 11 has not cut into the dress board 30. 【0039】 [1st processing process] Next, the first machining process is performed. As shown in Figure 6, in the first machining process, the cutting blade 11 and the dress board 30, which were positioned in the first positional relationship in the first positioning process, are moved relative to each other along the Y-axis direction (first direction), causing the cutting edge 25 of the rotating cutting blade 11 to cut into the dress board 30, thereby removing the dress board 30 while the cutting edge 25 is machined by the dress board 30. The first machining process is performed by the control unit 28, which drives the spindle motor of the cutting mechanism 20 and operates at least the Y-axis movement mechanism 18. In the first machining process, the cutting blade 11 and the dress board 30 are moved relative to each other along the Y-axis direction until the cutting blade 11 crosses the dress board 30 in the Y-axis direction and reaches outside the range on the opposite side of the dress board 30 (i.e., until the cutting edge 25 no longer cuts into the dress board 30). 【0040】 As a result of the first machining process, a first machining mark Sa is formed on the dress board 30, which is the trace of the overlapping region Ka being removed by the cutting blade 11. The first machining mark Sa is a concave trace that extends from one end to the other in the Y-axis direction of the dress board 30, and in the cross-section of the dress board 30 along the X-axis and Z-axis directions, it has an inverted arc-shaped cross-section that corresponds to a part of the circumferential shape on the tip (lower end) side of the cutting edge 25. 【0041】 [Second positioning process] After the first machining process, a second positioning process is performed. As shown in Figure 7, in the second positioning process, the cutting blade 11 and the dress board 30 held by the holding table 13 are moved relative to each other along the X-axis direction (second direction), which intersects with the Y-axis direction (first direction) and follows the first surface 301 of the dress board 30, so that the cutting blade 11 and the dress board 30 are positioned in a second positional relationship where they overlap when viewed from the Y-axis direction (first direction) (see Figure 7(B) in particular). As shown in Figure 7(B), in the second positional relationship set in the second positioning process, when viewed from the Y-axis direction, there is an overlapping region Kb enclosed by the outer edge of the cutting blade 11, the bottom surface of the previous first machining mark Sa, and the first surface 301 of the dress board 30. Also, when viewed from the Y-axis direction, a part of the cutting blade 11 positioned in the second positioning process overlaps with the previous first machining mark Sa. 【0042】 In the second positioning step, the positioning to the second positional relationship is performed by the control unit 28 operating at least the X-axis movement mechanism 16 by referring to the image of the dress board 30 captured by the imaging unit 27. As shown in Figure 7(A), in the second positioning step, in the Y-axis direction, the cutting blade 11 is outside the range of the dress board 30, and the cutting blade 11 does not cut into the dress board 30. The relative movement between the cutting blade 11 and the dress board 30 in the second positioning step only needs to include a movement component in the X-axis direction (second direction), and may also include movement components in the Y-axis direction (first direction) and the Z-axis direction (third direction), as long as no interference occurs between the cutting blade 11 and the dress board 30 during movement. A form in which the cutting blade 11 and the dress board 30 are also moved in the Z-axis direction during the positioning step will be mentioned in the modified examples described later. 【0043】 In the second positioning step, the relative movement of the cutting blade 11 and the dress board 30 in the X-axis direction (second direction) is set to less than the diameter of the cutting blade 11. In this embodiment, the relative movement of the cutting blade 11 and the dress board 30 in the X-axis direction in the second positioning step is set to be less than or equal to the radius of the cutting blade 11. The smaller the relative movement of the cutting blade 11 and the dress board 30 in the X-axis direction in the second positioning step, the more effective it is to suppress the height of the uneven shape of the dress board 30 between the two machining passes after the second machining step described later, thereby making the shape of the upper surface of the dress board 30 closer to flat. Therefore, from the viewpoint of improving the flatness of the upper surface of the dress board 30 after machining, it is preferable to make the relative movement of the cutting blade 11 and the dress board 30 in the X-axis direction in the second positioning step smaller than the radius of the cutting blade 11. Note that the movement in the second positioning step is not limited to less than the radius of the cutting blade 11, but may be in the range of greater than or equal to the radius of the cutting blade 11 and less than the diameter. 【0044】 [Second processing process] Next, the second machining process is performed. As shown in Figure 8, in the second machining process, the cutting blade 11 and the dress board 30, which were positioned in the second positional relationship in the second positioning process, are moved relative to each other along the Y-axis direction (first direction). The cutting edge 25 of the rotating cutting blade 11 is made to cut into the dress board 30, removing the dress board 30 while the cutting edge 25 of the cutting blade 11 is machined by the dress board 30. The second machining process is performed by the control unit 28, which drives the spindle motor of the cutting mechanism 20 and operates at least the Y-axis movement mechanism 18. In the second machining process, the cutting blade 11 and the dress board 30 are moved relative to each other along the Y-axis direction until the cutting blade 11 crosses the dress board 30 in the Y-axis direction and reaches outside the range on the opposite side of the dress board 30 (i.e., until the cutting edge 25 no longer cuts into the dress board 30). 【0045】 As a result of the second machining process, a second machining mark Sb is formed on the dress board 30, which is the trace of the overlapping region Kb being removed by the cutting blade 11. The second machining mark Sb is a concave trace that extends from one end to the other in the Y-axis direction of the dress board 30, and in the cross-section of the dress board 30 along the X-axis and Z-axis directions, it has an inverted arc-shaped cross-section that corresponds to a part of the circumferential shape on the tip (lower end) side of the cutting edge 25. 【0046】 In the second positioning step, by making the relative movement of the cutting blade 11 and the dress board 30 in the X-axis direction (second direction) less than the diameter of the cutting blade 11, the first machining path, which is the trajectory of the cutting blade 11 in the first machining step, and the second machining path, which is the trajectory of the cutting blade 11 in the second machining step, partially overlap when viewed from the Y-axis direction (first direction). In other words, in the second machining step, the cutting blade 11 passes through a part of the first machining mark Sa formed by the cutting blade 11 in the first machining step (moving without removing the dress board 30), and in the second machining step, the cutting edge 25 removes only the overlapping region Kb that does not overlap with the first machining mark Sa. As a result, in the second machining process, the shape of the area of ​​the dress board 30 that is removed by the cutting blade 11 (overlapping area Kb, second machining mark Sb) is asymmetrical with respect to the perpendicular Q connecting the point P where the surface of the cutting blade 11 intersects with the axis of rotation (axis C of the spindle 21) and the first surface 301 of the dress board 30, when viewed from the Y-axis direction (first direction). 【0047】 The machining process of this embodiment is applied to dressing (flat dressing) performed by rotating the cutting blade 11 with the direction of the rotation axis of the cutting blade 11 parallel to the first surface 301 of the dress board 30. However, the application of the machining method for cutting blades of this disclosure is not limited to dressing. For example, it can also be applied to truing for runout or rounding (shaping) of the cutting blade 11. In truing, the removal of the dress board 30 and shaping of the cutting blade 11 may be performed with the direction of the rotation axis of the cutting blade 11 extending in a direction intersecting the first surface 301 of the dress board 30. Even in such cases, by applying the settings of the second positioning step described above, the shape of the area of ​​the dress board 30 removed by the cutting blade 11 in the second machining step (second machining mark) is asymmetrical with respect to the perpendicular Q connecting the point P where the surface of the cutting blade 11 and the rotation axis intersect and the first surface 301 of the dress board 30, when viewed from the Y-axis direction (first direction). 【0048】 The above steps of first positioning, first machining, second positioning, and second machining are repeated. As described above, in multiple machining operations along multiple machining paths between the cutting blade 11 and the dress board 30, any nth machining operation becomes the first machining operation, and the next (n+1)th machining operation becomes the second machining operation. In other words, except for the machining along the first machining path performed on the unmachined dress board 30, all subsequent machining operations become second machining operations, with the immediately preceding operation being the first machining operation. Therefore, not only the second machining operation shown in Figure 8, but also the first machining operation shown in Figure 6(B) is a second or subsequent operation, so the shape of the area of ​​the dress board 30 removed by the cutting blade 11 (overlapping area Ka, first machining mark Sa) is asymmetrical with respect to the perpendicular Q connecting the point P where the surface of the cutting blade 11 intersects with the axis of rotation and the first surface 301 of the dress board 30, when viewed from the Y-axis direction (first direction). 【0049】 Furthermore, in the first machining pass performed on the unprocessed dress board 30, the shape of the area of ​​the dress board 30 removed by the cutting blade 11 may be set to be asymmetrical with respect to the perpendicular line Q, similar to the second and subsequent machining passes. 【0050】 In this embodiment, the cutting blade 11 is moved in one direction along the Y-axis during the first machining process, and moved in the opposite direction along the Y-axis during the second machining process, so that the cutting blade 11 completes one reciprocal motion along the Y-axis between the first and second machining processes. This reduces the amount of movement of the cutting blade 11 between each machining process, enabling efficient machining. However, the operation is not limited to this embodiment, and the cutting blade 11 may be set to move in the same direction along the Y-axis between the first and second machining processes. 【0051】 Figure 9 shows the state in which machining marks S are formed over the entire X-axis direction of the upper surface of the dress board 30 by repeatedly performing the set of the first positioning step, first machining step, second positioning step, and second machining step. Each machining mark S is a recess having an inverted arc-shaped cross-section corresponding to a part of the circumferential shape of the cutting edge 25 of the cutting blade 11. Multiple machining marks S are formed on the dress board 30 in a continuous line without gaps in the X-axis direction, and the original first surface 301 of the dress board 30 does not remain between each machining mark S. Therefore, compared to the machining method of the comparative example shown in Figure 4, the number of machining passes per unit area of ​​the dress board 30 is large, and machining of the cutting blade 11 that efficiently utilizes the first surface 301 of the dress board 30 is achieved. 【0052】 Furthermore, although there is a slight difference in the height of the unevenness in the Z-axis direction between the height position Ha of the protruding shape between adjacent processing marks S and the height position Hb of the bottom of each processing mark S on the upper surface of the processed dress board 30, the difference between the height position Ha and the height position Hb on the upper surface of the dress board 30 is smaller and the shape is closer to flat compared to when the processing method of the comparative example shown in Figure 4 is performed. In addition, the plane including the height position Ha of the protruding shape between the multiple processing marks S and the plane including the height position Hb of the bottom of the multiple processing marks S are both approximately parallel to the original first surface 301 of the dress board 30. As a result, once the first stage of processing shown in Figure 9 is completed, the dress board 30 with multiple processing marks S formed on it can be used again to perform processing of the cutting blade 11 in the second and subsequent stages (dressing and truing) under processing conditions similar to the first stage of processing in which the cutting blade 11 cuts into the flat first surface 301. Preferably, the difference between the height position Ha and the height position Hb in the Z-axis direction is 200 μm or less. In other words, it is preferable that the machining marks S removed by the first and second machining processes have a shape that includes a surface along the first surface 301 with a height of 200 μm or less. By satisfying this condition, machining of the second and subsequent cutting blades 11 can be performed well. 【0053】 Figure 10 shows the case where the second stage of machining is performed using the dress board 30, which has completed the first stage of machining as shown in Figure 9, with a cutting blade 11. In the second stage of machining, the cutting blade 11 is set to cut at a position deeper than the height position Hb of the bottom of the machining mark S from the first stage, and the first positioning step, first machining step, second positioning step, and second machining step are repeated in the same way as in the first stage of machining described above, so that the first machining mark (first machining pass of the cutting blade 11) in the first machining step and the second machining mark (second machining pass of the cutting blade 11) in the second machining step partially overlap. As a result, after the second stage of machining, multiple machining marks S of the same shape as after the first stage of machining shown in Figure 9 are formed on the upper surface of the dress board 30. In other words, the dress board 30 maintains a nearly flat upper surface shape, similar to when the first stage of machining is completed, while reducing the thickness by the amount removed in the second stage of machining. 【0054】 If sufficient thickness remains in the dress board 30 after the completion of the second stage of processing, the third and subsequent stages of processing can be carried out in the same manner as described above. For example, if the thickness from the first surface 301 to the second surface 302 of the dress board 30 in its initial state before the first stage of processing is 1 mm, the dress board 30 can be repeatedly used by processing multiple stages until the remaining thickness of the dress board 30 is about 0.5 mm. 【0055】 As described above, the processing method of this disclosure allows for the processing of the cutting blade 11 by increasing the number of processing passes per step in the thickness direction of the dress board 30, while suppressing the step difference in the uneven shape of the dress board 30 after processing, and enabling processing with multiple processing passes at different positions in the thickness direction of the dress board 30. This makes it possible to process the cutting blade 11 using the dress board 30 efficiently without waste, and to increase the number of times the dress board 30 can be used. As shown in the comparative example in Figure 4, existing cutting blade processing methods are based on the premise of processing the next processing pass while avoiding the previous processing pass, and multiple processing passes extending in the first direction (Y axis direction) are formed with gaps between them without being continuous in the second direction (X axis direction). In contrast, the processing method of this disclosure is not bound by this premise and focuses on increasing the density of processing passes in the second direction (X axis direction), and processes so that the previous processing pass in the first processing step and the next processing pass in the second processing step partially overlap. As a result, as described above, it was possible to increase the number of times the dress board 30 can be used compared to the comparative example. Furthermore, experimental and research results have shown that even when the machining process is carried out in two consecutive machining steps, as in the machining method of this disclosure, in such a way that the machining paths partially overlap, and the region in which the cutting blade 11 removes the dress board 30 is asymmetrical with respect to the perpendicular Q, machining such as flat dressing of the cutting blade 11 can be performed with sufficiently high precision. 【0056】 Furthermore, as in the machining method of this disclosure, by partially overlapping the machining of the previous machining pass and the machining of the next machining pass, the amount of dressing board 30 removed in each machining pass is relatively reduced, thereby reducing the load and resistance acting on the cutting blade 11 in each machining process. Moreover, in the machining method of this disclosure, the cutting blade 11 and the dressing board 30 are moved relatively by a fixed amount in the X-axis direction in the second positioning step without changing the cutting depth of the cutting blade 11 in the Z-axis direction for each machining pass, so that the area of ​​dressing board 30 removed by the cutting blade 11 is always the same amount in each machining process. As a result, it is easier to precisely control the machining of the cutting edge 25 of the cutting blade 11, and the control content during machining can be made simple and the control burden low. This makes it possible to control the tip shape of the cutting edge 25 with high precision when flat dressing is performed on the cutting blade 11. 【0057】 Next, with reference to Figure 11, a first modified example of the cutting blade processing method of this disclosure will be described. When processing is performed to shape the cutting edge 25 of the cutting blade 11 using the dressing board 30, the cutting edge 25 gradually wears down and the diameter of the cutting blade 11 decreases. As shown in the first modified example processing method in Figure 11, processing may be performed taking into account the wear of the cutting blade 11. In the first modified example, the holding step is performed in the same manner as in the above embodiment, so a detailed explanation is omitted. Also, in Figure 11, the holding table 13 for holding the dressing board 30 in the holding step is not shown. 【0058】 [Positioning process] In the positioning process performed after the holding process, the cutting blade 11 and the dress board 30 held on the holding table 13 are positioned so that they overlap when viewed from the Y-axis direction (first direction) along the first surface 301. 【0059】 [Processing process] In the subsequent machining process, the cutting blade 11 and the dressing board 30 are moved relative to each other along the Y-axis direction (first direction), causing the cutting edge 25 of the rotating cutting blade 11 to cut into the dressing board 30, thereby removing the dressing board 30 while the cutting edge 25 is machined by the dressing board 30. 【0060】 Machining (positioning step and machining step) of the cutting blade 11 is performed multiple times (in multiple machining passes) at different positions in the X-axis direction (first direction) on the dress board 30. Then, in two consecutive machining passes (nth and n+1th times), the positioning step for the previous machining pass is designated as the first positioning step, the machining step for the previous machining pass as the first machining step, the positioning step for the next machining pass as the second positioning step, and the machining step for the next machining pass as the second machining step, and the positioning step and machining step for each machining pass are performed in the same manner as in the above embodiment. Therefore, in each machining step, the shape of the area of ​​the dress board 30 removed by the cutting blade 11 (machining marks S) is asymmetrical with respect to the perpendicular Q connecting the point P where the surface of the cutting blade 11 intersects with the axis of rotation and the first surface 301 of the dress board 30, when viewed from the Y-axis direction (first direction). 【0061】 [Height correction process] When the positioning and machining processes are repeated multiple times, a height correction process is performed to move the cutting blade 11 and the dress board 30 relative to each other along the Z-axis direction (third direction) that intersects with the first surface 301 of the dress board 30 before executing the next machining process. In each machining process, the cutting edge 25 is worn down and its diameter decreases as a result of machining along the machining path of the cutting blade 11. If machining along one machining path is insufficient to complete the machining of the cutting blade 11, the height correction process uses the amount of wear on the cutting edge 25 (decrease in the diameter of the cutting blade 11) as a correction value to increase the cutting depth of the cutting blade 11 into the dress board 30 in the next machining path. In this embodiment, the height correction process is performed by the control unit 28 by operating at least the Z-axis movement mechanism 19. 【0062】 In Figure 11, the arrow Fa indicates the movement trajectory of the cutting blade 11 in the X-axis direction (second direction) during the positioning process, and the arrow Fb indicates the movement trajectory of the cutting blade 11 in the Z-axis direction (third direction) during the height correction process. The movement by arrow Fb represents the correction value in the height correction process. As can be seen from this movement trajectory, in the height correction process, before proceeding to the next machining process, the height position of the cutting blade 11 in the Z-axis direction (third direction) is corrected by moving it downward in the Z-axis direction by the amount of wear of the cutting edge 25 in the previous machining process. This ensures that the height position of the lower end of the cutting edge 25 (the depth of cut of the cutting blade 11 in the Z-axis direction into the dress board 30) is consistent in each machining process. In other words, similar to the machining results shown in Figure 9, after completing one stage of machining on the dress board 30 and forming multiple machining marks S arranged continuously in the X-axis direction on the upper surface of the dress board 30, the plane including the height position Hc of the bottom of the multiple machining marks S is approximately parallel to the original first surface 301 of the dress board 30. In other words, after multiple processing steps, the upper surface of the dress board 30 will have processing marks S at roughly uniform height positions that absorb the wear of the cutting edge 25. 【0063】 Information on the amount of wear of the cutting edge 25 during the machining process can be obtained by measurement after the machining process using a sensor that measures the shape of the cutting blade 11. In this case, the measured value is used as the correction value in the height correction process. Alternatively, if there is data on the amount of wear of the cutting edge 25 (measurement data of the shape of the cutting blade 11) from a previous machining process performed under the same machining conditions as the current machining process (for example, the materials of the cutting blade 11 and the dress board 30 are the same as this time), the control unit 28 may read the previous data under the same machining conditions and use it as the correction value in the height correction process. 【0064】 In the example shown in Figure 11, the movement trajectory of the cutting blade 11 in the X-axis direction (second direction) during the positioning process (arrow Fa) and the movement trajectory of the cutting blade 11 in the Z-axis direction (third direction) during the height correction process (arrow Fb) are shown separately. However, the cutting blade 11 may also be moved by a diagonally downward movement trajectory which is a combination of the movement components of arrow Fa and arrow Fb. In other words, it is possible to move the dress board 30 in the X-axis direction by the X-axis movement mechanism 16 during the positioning process while simultaneously moving the cutting blade 11 in the Z-axis direction by the Z-axis movement mechanism 19 during the height correction process. Since the positioning process is performed when the cutting blade 11 has not yet cut into the dress board 30, it is possible to perform the relative movement of the cutting blade 11 and the dress board 30 in the Z-axis direction for the correction in the height correction process simultaneously with the relative movement in the X-axis direction during the positioning process. 【0065】 By applying the processing method of the first modified example described above, the shape of the top surface of the dress board 30 remains flat after the first stage of processing. Therefore, when performing the second stage of processing with a different type of cutting blade (with different conditions such as wear resistance) than the cutting blade 11 used in the first stage of processing, the shape correction of the cutting blade can be performed with high precision without requiring special control. Furthermore, by applying the above control method of the first modified example to the second stage of processing, the same effect can be obtained for the third stage and beyond. 【0066】 The machining method of the second modified example shown in Figure 12 differs from the first modified example shown in Figure 11 in that, when the cutting edge 25 is worn down during the machining process and the diameter of the cutting blade 11 decreases, the next machining process is executed immediately after the positioning process without performing a height correction process. In this case, as the machining process is repeated multiple times and the number of machining paths aligned in the X-axis direction increases, the height position of the lower end of the cutting edge 25 (the depth of the cutting blade 11 in the Z-axis direction into the dress board 30) in each machining process gradually becomes shallower. As a result, when multiple machining marks S are formed that are continuously arranged in the X-axis direction, the plane containing the height position Hd of the bottom of these multiple machining marks S extends in a direction that intersects the original first surface 301. 【0067】 When machining the dress board 30 in the second and subsequent stages, if the machining conditions are the same as for the first stage, the degree of wear on the cutting edge 25 of the cutting blade 11 along each machining path is expected to be the same as during the first stage. In such a case, the multiple machining marks S formed in the second stage are expected to have the same relationship in terms of the height positions of the bottom of the multiple machining marks S during the first stage. Therefore, when the shape correction of the same type of cutting blade 11 is continuously performed over multiple stages, even without performing a height correction process like in the first modified example, there is little variation in the amount of dress board 30 removed in each machining process from the second stage onward, and the cutting blade 11 can be machined with high precision even when the cutting edge 25 is gradually worn down. In other words, if the first and second stages of machining the dress board 30 are performed with the same type of cutting blade 11, applying the second modified machining method, which does not perform height compensation, allows for shape correction of the cutting blade 11 in the second stage of machining with the same amount of material removed from the dress board 30 as in the first stage of machining. This has the advantage of eliminating the need for height compensation control and thus reducing the effort required for control. The same effect can be obtained for machining the third stage and beyond. 【0068】 The third modification shown in Figure 13 involves performing multiple machining operations by changing the relative position of the cutting blade 11 and the dress board 30 in the Z-axis direction (third direction) within the region along each machining path. In the third modification, first, in the first region Ea along the first machining path, the cutting blade 11 is positioned at a high position in the Z-axis direction, indicated by the dashed line, and the relative position of the cutting blade 11 and the dress board 30 is changed in the Y-axis direction (first direction) to allow the rotating cutting blade 11 to cut into the dress board 30 and perform the first machining operation. Subsequently, the cutting blade 11 is positioned at a deep position in the Z-axis direction, indicated by the solid line, and the relative position of the cutting blade 11 and the dress board 30 is changed in the Y-axis direction (first direction) to allow the rotating cutting blade 11 to cut into the dress board 30 and perform the second machining operation. Once the first and second machining operations are complete, machining marks Sc are formed on the dress board 30. This processing mark Sc has the same shape as the first processing mark Sa shown in Figure 6 of the above embodiment. 【0069】 Next, the cutting blade 11 and the dress board 30 are moved relative to each other along the X-axis direction (second direction), changing the position of the cutting blade 11 from the first region Ea to the second region Eb. Then, machining is performed in the second region Eb. Machining in the second region Eb is performed in the same way as machining in the first region Ea. First, the cutting blade 11 is positioned at a high position in the Z-axis direction, indicated by the dashed line, and the relative position of the cutting blade 11 and the dress board 30 is changed in the Y-axis direction (first direction), causing the rotating cutting blade 11 to cut into the dress board 30 to perform the third machining. Next, the cutting blade 11 is positioned at a deep position in the Z-axis direction, indicated by the solid line, and the relative position of the cutting blade 11 and the dress board 30 is changed in the Y-axis direction (first direction), causing the rotating cutting blade 11 to cut into the dress board 30 to perform the fourth machining. When the third and fourth machining are completed, machining marks Sd are formed on the dress board 30. This processing mark Sc has the same shape as the second processing mark Sb shown in Figure 8 of the above embodiment. 【0070】 In the third modified example, as described above, the first machining process is performed by combining the first and second machining processes in the first region Ea, and the second machining process is performed by combining the third and fourth machining processes in the second region Eb. In the second machining process, as viewed from the Y-axis direction, a portion of the cutting blade 11 is positioned to overlap with the machining marks Sc formed in the first and second machining processes of the first machining process. As a result, the machining content is the same as in the above embodiment, and the same effects as in the above embodiment can be obtained. Furthermore, by applying the machining of the third modified example, the cutting blade 11 is worn down more easily (shape correction of the cutting blade 11 in each machining pass progresses more easily), and when the depth of cut of the cutting blade 11 in the Z-axis direction does not need to be shallow, the number of machining passes can be reduced and the machining marks Sc can be brought closer to a plane. 【0071】 In the embodiments and modifications described above, in machining along two adjacent machining paths in the X-axis direction, the machining marks from the later machining step always partially overlap with the machining marks from the immediately preceding machining step. However, the machining method of this disclosure is not limited to such forms. For example, in the fourth modification shown in Figure 14, after a machining mark Se is formed on the dress board 30 by the cutting blade 11 in the (n-1)th machining step, in the subsequent first positioning step, the cutting blade 11 and the dress board 30 are moved relative to each other in the X-axis direction (second direction) by an amount equal to or greater than the diameter of the cutting blade 11. Then, in the nth machining step (first machining step) performed after the first positioning step, a first machining mark Sf is formed at a predetermined distance from the previous machining mark Se in the X-axis direction. The dress board 30 has a residual region Kc between the machining mark Se and the first machining mark Sf, and the residual region Kc includes the first surface 301. The shape of the first machining mark Sf at this stage is symmetrical with respect to the perpendicular Q connecting the point P where the surface of the cutting blade 11 intersects with the axis of rotation (the axis C of the spindle 21) and the first surface 301 of the dress board 30, when viewed from the Y-axis direction (first direction). 【0072】 In the second positioning step, which follows the nth machining step (first machining step), the cutting blade 11 and the dress board 30 are moved relative to each other in the X-axis direction (second direction) to the opposite side from the first positioning step, so that the cutting blade 11 returns to the direction of the machining mark Se from the step before last. The amount of movement in the X-axis direction in this second positioning step is less than the diameter of the cutting blade 11, as in the embodiment described above, and the cutting blade 11 and the dress board 30 are positioned in a second positional relationship where they overlap when viewed from the Y-axis direction (first direction). In other words, the cutting blade 11 is positioned so that it overlaps with at least a part of the remaining region Kc between the machining mark Se from the step before last and the first machining mark Sf when viewed from the Y-axis direction (first direction). 【0073】 In the subsequent (n+1)th machining process (second machining process), the cutting blade 11 and the dress board 30, which were positioned in the second positional relationship in the second positioning process, are moved relative to each other along the Y-axis direction (first direction). The cutting edge 25 of the rotating cutting blade 11 is driven into the dress board 30 to remove the dress board 30, while the cutting edge 25 of the cutting blade 11 is machined by the dress board 30. After this second machining process, the area of ​​the remaining region Kc of the dress board 30 that the cutting blade 11 has passed through is removed, and a second machining mark Sg is formed that is continuous in the X-axis direction with respect to the machining mark Se and the first machining mark Sf, respectively. In the second machining process, the area removed by the cutting blade 11 when forming the second machining mark Sg (part of the remaining area Kc) is asymmetric with respect to the perpendicular Q connecting the point P where the surface of the cutting blade 11 intersects with the axis of rotation (the axis C of the spindle 21) and the first surface 301 of the dress board 30, when viewed from the Y-axis direction (first direction). 【0074】 As can be seen from the fourth modification described above, when repeating multiple machining processes, the positioning process may not always proceed in one direction along the X-axis (second direction), but may also include an action to return to the opposite side along the X-axis in some of the positioning processes. Furthermore, in some of the machining processes (first machining process), the region in which the cutting blade 11 removes the dress board 30 may be symmetrical with respect to the perpendicular Q connecting the point P where the surface of the cutting blade 11 intersects with the axis of rotation (axis C of the spindle 21) and the first surface 301 of the dress board 30. 【0075】 As in the fourth modification, when changing the position of the machining path in the X-axis direction (second direction), by including movement in the opposite direction as well as one direction, the region in which the rotating cutting blade 11 removes the dressing board 30 is switched between a state in which up-cutting, where machining progresses from bottom to top, is mainly performed, and a state in which down-cutting, where machining progresses from top to bottom, is mainly performed. In up-cutting, the discharge of abrasive grains that have fallen off the cutting edge 25 during dressing is relatively good, so the load on the abrasive grains is small and contamination tends to be small. As a result, the tangential load on the cutting edge of the cutting edge 25 is small, resulting in a shallow chip pocket and a surface that looks like the cutting edge has been rubbed. In down-cutting, the discharge of abrasive grains that have fallen off the cutting edge 25 during dressing is relatively poor, so the load on the abrasive grains is large and contamination tends to be large. As a result, the tangential load on the cutting edge of the cutting edge 25 is large, resulting in a deep chip pocket and a sharp cutting edge. Focusing on the difference between the effects of up-cutting and down-cutting, by applying the fourth modified example, the cutting edge state of the cutting edge 25 of the cutting blade 11 can be adjusted by flattening the tip of the cutting edge 25 with flat dressing and then appropriately selecting between the up-cutting and down-cutting machining states. 【0076】 In the first to fourth modified examples, the shapes of the machining marks illustrated in the figures are exaggerated in their representation of the changes in the shape of the machining marks. Although the size of the machining marks in each machining pass appears to differ considerably, in reality, the amount of material processed in each machining pass due to the shape correction of the cutting blade is much smaller than shown in the figures, and similar machining marks are obtained each time. However, by implementing the control described in each of the modified examples above, even higher precision machining can be achieved. 【0077】 In the embodiments and modifications described above, a dress board unit 33 is used, in which a dress board 30 is attached to a ring frame 32 via tape 31. The dress board unit 33 is then attached to the holding table 13 to perform machining on the cutting blade 11. However, the invention is not limited to this configuration. For example, an independent sub-table (an example of a holding table) equipped with a dress board may be provided at a location separate from the holding table 13 that holds the workpiece unit 4 (such as a location connected to the outer circumference of the holding table 13). In each machining process, the cutting blade 11 may be used to cut into the dress board provided on this sub-table. 【0078】 In the above embodiments and their variations, when machining along each machining path by moving the cutting blade 11 and the dressing board 30 relative to each other in the Y-axis direction (first direction), if the shape correction (flat dressing) of the cutting edge 25 of the cutting blade 11 is completed in the middle of the machining path (in the middle of the width of the dressing board 30), moving the cutting blade 11 to the end of the machining path may cause excessive wear of the already corrected cutting edge 25, potentially shortening the life of the cutting blade 11. In such cases, the shape correction machining of the cutting blade 11 may be terminated in the middle of the machining path. However, if machining marks are formed on the dressing board 30 up to the middle of the width direction, it becomes difficult to perform the next machining with the cutting blade 11 using the dressing board 30 thereafter, so it is preferable to perform additional machining to smooth the upper surface shape of the dressing board 30. 【0079】 Additional processing to shape the top surface of the dress board 30 is performed, for example, using a board processing blade (not shown) different from the cutting blade 11. The cutting device 10 is equipped with an auto blade changer (not shown) that holds multiple cutting blades and automatically attaches and detaches them to the spindle 21 (replaces cutting blades), and the board processing blades are stored in the auto blade changer. When additional processing is performed on the dress board 30, the auto blade changer removes the original cutting blade 11 from the spindle 21 and attaches the board processing blade to the spindle 21 in its place. The board processing blade to be attached to the spindle 21 is selected to have the same diameter as the removed cutting blade 11. The board processing blade is then positioned at the continuation of the processing path where the original cutting blade 11 has partially processed the surface, and the rotating board processing blade and the dress board 30 are moved relative to each other in the Y-axis direction to process the remaining portion of the processing path. This results in a shape where the machining marks on the dress board 30 are not interrupted in the Y-axis direction, and the upper surface of the dress board 30 can be maintained in a nearly flat shape. In addition, by replacing the blade with a board machining blade to shape the upper surface of the dress board 30, the wear of the expensive cutting blade 11 used to machine the workpiece 1 can be suppressed, thereby reducing the operating cost of the cutting device 10. 【0080】 Furthermore, the embodiments of the present invention are not limited to the embodiments and modifications described above, and may be modified, substituted, or altered in various ways without departing from the spirit of the technical idea of ​​the present invention. Moreover, if the technical idea of ​​the present invention can be realized in a different way by advances in the art or by other derived arts, it may be implemented by that method. Accordingly, the claims cover all embodiments that may fall within the scope of the technical idea of ​​the present invention. [Industrial applicability] 【0081】 The cutting blade processing method of this disclosure improves the utilization efficiency of the dressing board used to process the cutting blade, reduces the operating costs of the cutting equipment, and minimizes the environmental burden associated with replacing the dressing board. [Explanation of symbols] 【0082】 1: Workpiece 10: Cutting equipment 11: Cutting blade 13: Holding Table 15: Table rotation mechanism 16:X-axis movement mechanism 18:Y-axis movement mechanism 19:Z-axis movement mechanism 20: Cutting mechanism 21: Spindle (rotating axis) 25: Cutting edge 27: Imaging Unit 28: Control Unit 30: Dressboard 31: Tape 32: Ring Frame 33: Dressboard Unit 301: The first side of the dress board 302: Dressboard, side 2 C: Spindle axis Ka: Overlapping region Kb: Overlapping area Kc:Residual area P: The point where the surface of the cutting blade intersects with the axis of rotation. Q: Perpendicular line S: Machining marks Sa: 1st machining mark Sb: 2nd machining mark Sc: Machining marks Sd: Machining marks Se: Machining marks Sf: 1st machining mark Sg: 2nd machining mark X:Second direction Y: First direction Z: 3rd direction

Claims

[Claim 1] A method for processing a cutting blade using a dress board having a plate shape, A holding step involves holding the second surface of the dress board, which is located opposite in the thickness direction to the first surface of the dress board into which the cutting blade is cut, with the holding table. A first positioning step involves positioning the cutting blade, which rotates around a rotation axis, and the dress board, which is held on a holding table, in a first positional relationship where the cutting blade and the dress board overlap when viewed from a first direction along the first surface. A first machining step involves moving the cutting blade and the dress board, which are positioned in the first positional relationship in the first positioning step, relatively along the first direction, removing the dress board with the rotating cutting blade, and machining the cutting blade with the dress board. After the first machining step, the cutting blade and the dress board are moved relative to each other along a second direction that intersects the first direction and follows the first surface, and the cutting blade and the dress board held on the holding table are positioned in a second positional relationship in which the cutting blade and the dress board overlap when viewed from the first direction. The second processing step involves moving the cutting blade and the dress board, which are positioned in the second positional relationship in the second positioning step, relative to each other along the first direction, and removing the dress board with the rotating cutting blade while processing the cutting blade with the dress board. In the first and second processing steps, the shape of the area of ​​the dress board removed by the cutting blade is asymmetric with respect to the perpendicular line connecting the point where the surface of the cutting blade intersects with the axis of rotation when viewed from the first direction, and the first surface of the dress board. A method for processing cutting blades, characterized by the features described above. [Claim 2] The relative distance of movement along the second direction in the second positioning step is smaller than the radius of the cutting blade. The method for machining a cutting blade according to feature 1. [Claim 3] The processing marks removed from the dress board by the first and second processing steps include surfaces along the first surface with a height of 200 μm or less of unevenness. The method for machining a cutting blade according to feature 2. [Claim 4] A method for processing a cutting blade using a dress board having a plate shape, A holding step involves holding the second surface of the dress board, which is located opposite in the thickness direction to the first surface of the dress board into which the cutting blade is cut, with the holding table. A positioning step involves positioning the cutting blade, which rotates around a rotation axis, and the dress board, which is held on the holding table, such that the cutting blade and the dress board overlap when viewed from a first direction along the first surface. Following the positioning step, the cutting blade and the dress board are moved relative to each other along the first direction, and the cutting blade is processed by the dress board while the dress board is removed by the rotating cutting blade. After the positioning step and the machining step have been repeated multiple times, a height correction step is performed to move the cutting blade and the dress board relative to each other along a third direction intersecting the first surface of the dress board before performing the next machining step. In the processing step, the shape of the area of ​​the dress board removed by the cutting blade is asymmetric with respect to the perpendicular line connecting the point where the surface of the cutting blade intersects with the axis of rotation when viewed from the first direction, and the first surface of the dress board. A method for processing cutting blades, characterized by the features described above.

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