Dressing method, dressing device, and grinding wheel

Abstract

Provided are a dressing method, a dressing device, and a grinding wheel capable of finely adjusting the grinding performance of the grinding wheel. 【Solution means】In the dressing method, a grinding wheel G formed by binding abrasive grains with a binder is held with the grinding surface Gf of the grinding wheel G exposed, and while condensing the laser beam LA1 and irradiating the grinding surface Gf, the irradiation region irradiated with the laser beam LA1 on the grinding surface Gf is moved to melt and evaporate the binder and adjust the protrusion amount of the abrasive grains. Then, by changing the intensity of the laser beam LA1, the protrusion amount of the abrasive grains on the grinding surface Gf of the grinding wheel G is adjusted.

Description

Technical Field

[0001] The present invention relates to a dressing method, a dressing device, and a grinding wheel.

Background Art

[0002] A non-contact dressing and truing method for a grinding wheel has been proposed in which the binder on the grinding surface or auxiliary grinding surface of a grinding wheel that requires dressing or truing is melted and evaporated to control the amount of abrasive grains protruding and the grinding wheel profile (see, for example, Patent Document 1). In this non-contact dressing and truing method for a grinding wheel, the laser is irradiated from a laser oscillator onto the grinding surface or auxiliary grinding surface of the grinding wheel to melt and evaporate the binder on the grinding surface or auxiliary grinding surface of the grinding wheel, thereby controlling the amount of abrasive grains protruding and the grinding wheel profile.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in dressing and truing of a grinding wheel, it may be required to finely adjust the grinding performance of the grinding wheel according to the use of the grinding wheel. In this case, with the non-contact dressing and truing method for a grinding wheel described in Patent Document 1, there is a possibility that the amount of protruding abrasive grains cannot be sufficiently controlled so as to achieve the required grinding performance of the grinding wheel.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a dressing method, a dressing device, and a grinding wheel capable of finely adjusting the grinding performance of the grinding wheel.

Means for Solving the Problems

[0006] In order to achieve the above object, the dressing method according to the present invention is as follows: A dressing method for adjusting the protrusion amount of abrasive grains by holding a grindstone formed by binding abrasive grains with a binder in a state where the grinding surface of the grindstone is exposed, and irradiating the grinding surface with a laser beam to melt and evaporate the binder, comprising: While condensing the laser light so that the area of the irradiation region irradiated with the laser light on the grinding surface is at least smaller than the area of the grinding surface and irradiating the grinding surface, while moving the irradiation region on the grinding surface, by changing the intensity of the laser light, a plurality of regions having different average values of the protruding amounts are formed on the grinding surface

[0007] From another aspect, the dressing device according to the present invention includes: a grindstone holding unit that holds a grindstone formed by binding abrasive grains with a binder in a state where the grinding surface of the grindstone is exposed; a laser head that condenses a laser beam so that the area of an irradiation region on the grinding surface irradiated with the laser beam is at least smaller than the area of the grinding surface, and irradiates the grinding surface; a head posture changing unit that changes the posture of the laser head to change the radiation direction of the laser beam, thereby moving the irradiation region on the grinding surface; a control unit that controls the head posture changing unit to move the irradiation region on the grinding surface, and controls the laser head to change the intensity of the laser beam, Form a plurality of regions on the grinding surface having different average values of the protruding amounts of the abrasive grains and is provided with a control unit.

Advantages of the Invention

[0008] According to the present invention, While moving the irradiation region of the laser light on the grinding surface of the grinding wheel, by changing the intensity of the laser light, a plurality of regions having different average values of the protruding amounts are formed on the grinding surface the grinding performance of the grindstone can be finely adjusted.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] Hereinafter, a dressing method according to an embodiment of the present invention will be described with reference to the drawings. In the dressing method according to this embodiment, a grinding wheel formed by binding abrasive grains with a binder is held in a state where the grinding surface of the grinding wheel is exposed, and laser light is condensed so that the area of the irradiation region on the grinding surface irradiated with the laser light is at least smaller than the area of the grinding surface, and while irradiating the grinding surface, the above-mentioned irradiation region on the grinding surface is moved to melt and evaporate the binder, thereby adjusting the protrusion amount of the abrasive grains. In this dressing method, while moving the irradiation region on the grinding surface, by changing the intensity of the laser light, a plurality of regions with different average values of the protrusion amount of the abrasive grains are formed on the grinding surface.

[0011] As shown in FIG. 1, the dressing apparatus according to this embodiment includes a grinding wheel holding unit 11, a laser head 12, a head posture changing unit 13, a control unit 21, and a terminal device 22. The grinding wheel holding unit 11 holds the grinding wheel G in a state where its grinding surface Gf is exposed. The grinding wheel G is a metal bond grinding wheel, a ceramic bond grinding wheel, or the like. The grinding wheel G is formed by binding a plurality of abrasive grains with a binder. Here, as the abrasive grains, single crystal diamond, polycrystalline diamond, single crystal cubic boron nitride, polycrystalline cubic boron nitride, etc. can be adopted. This grinding wheel G has, for example, a long grinding surface Gf in plan view, and is mounted on the tip of a long honing tool for honing the inner surface of the processing hole of the workpiece so that the longitudinal direction of the grinding surface Gf is along the longitudinal direction of the honing tool. With the grinding surface Gf in contact with the inner surface of the processing hole of the workpiece, the honing tool is rotated about the central axis along the longitudinal direction of the honing tool, so that the grinding surface Gf slides in the short direction to grind the inner surface of the processing hole.

[0012] The laser head 12 is arranged such that the irradiation port of its laser light LA1 faces the grinding wheel holding unit 11, and condenses the laser light LA1 so that the area of the irradiation region on the grinding surface Gf is at least smaller than the area of the grinding surface Gf, and irradiates the grinding surface Gf. The laser head 12 has, for example, a YAG laser excited dye laser oscillator, a YAG laser oscillator, etc.

[0013] The head posture changing unit 13 changes the emission direction of the laser beam LA1 by changing the posture of the laser head 12. As shown by the arrow AR1, the head posture changing unit 13 moves the irradiation area on the grinding surface Gf of the grinding wheel G held by the grinding wheel holding unit 11 where the laser beam LA1 is irradiated by changing the posture of the laser head 12.

[0014] The control unit 21 has, for example, a PLC (Programmable Logic Controller), and controls the laser head 12 and the head posture changing unit 13 based on the setting information set by the user via the terminal device 22. The control unit 21 controls the head posture changing unit 13 to move the irradiation area of the laser beam LA1 on the grinding surface Gf of the grinding wheel G, and controls the laser head 12 to change the intensity of the laser beam LA1, thereby forming a plurality of regions on the grinding surface Gf of the grinding wheel G where the protrusion amounts of the abrasive grains are different. Here, the control unit 21 has a correlation information storage unit (not shown) that stores correlation information indicating the correlation between the intensity of the laser beam LA1 and the protrusion amount of the abrasive grains, and based on the setting information indicating the set value of the protrusion amount of the abrasive grains set by the user via the terminal device 22 and the correlation information, determines the intensity of the laser beam LA1 irradiated from the laser head 12 to the grinding surface Gf of the grinding wheel G. Then, the control unit 21 controls the laser head 12 so that the laser beam LA1 having the determined intensity is output from the laser head 12.

[0015] Here, the features of the dressing method according to the present embodiment will be described while comparing with the dressing method according to the comparative example. Here, the case of dressing the grinding surface of a grinding wheel having a long grinding surface as the grinding wheel will be described. In the dressing method according to the comparative example, while rotating a cylindrical grinder in which abrasive grains finer than the abrasive grains of the grinding wheel are embedded in the contact surface with the grinding wheel on the grinding surface of the grinding wheel, the grinding surface is brought into contact with the grinding surface of the grinding wheel and slid along the longitudinal direction of the grinding surface to perform dressing. FIG. 2(A) shows the result of comparing the average value Rz of the protrusion amount of the abrasive grains on the grinding surface when dressing the grinding surfaces of four grinding wheels by the dressing method according to the comparative example and when dressing the grinding surfaces of four grinding wheels by the dressing method according to the present embodiment. As shown in FIG. 2(A), in the case of the dressing method according to the comparative example, the average value of the protrusion amount of the abrasive grains of the four grinding wheels became larger than 12 μm, and the variation in the protrusion amount was also about 5 μm. On the other hand, in the case of the dressing method according to the present embodiment, the average value of the protrusion amount of the abrasive grains of the four grinding wheels could be suppressed to about 10 μm, and the variation in the protrusion amount could also be suppressed to about 1 μm. Further, when honing the workpiece using each of the four grinding wheels dressed by the dressing method according to the comparative example, as shown in FIG. 2(B), the surface roughness Rzw of the inner wall of the machined hole of the workpiece had a variation of 2 μm or more. In FIG. 2(B), the results when honing the workpiece using each of the four grinding wheels dressed by the dressing method according to the comparative example are shown by round marks with different degrees of shading. On the other hand, when honing the workpiece using each of the four grinding wheels dressed by the dressing method according to the present embodiment, as shown in FIG. 2(C), the surface roughness Rzw of the inner wall of the machined hole of the workpiece had a variation of 1.5 μm or less. In FIG. 2(C), the results when honing the workpiece using each of the four grinding wheels dressed by the dressing method according to the present embodiment are shown by diamond marks and rectangular marks with different degrees of shading or sizes.Furthermore, as shown in FIG. 3, the variation Rzv in the protrusion amount across the entire grinding surface of the grinding wheel dressed by the dressing method according to the comparative example was about 55 μm, whereas the variation Rzv in the protrusion amount across the entire grinding surface of the grinding wheel dressed by the dressing method according to the present embodiment was about 25 μm. From the above results, it can be seen that by adopting the dressing method according to the present embodiment, the protrusion amount of the grinding wheel can be made smaller and the variation in the protrusion amount among a plurality of grinding wheels when dressing a plurality of grinding wheels can also be reduced, as compared with the case of adopting the dressing method according to the comparative example. It can also be seen that the variation in the protrusion amount of the abrasive grains across the entire grinding surface of the grinding wheel can be reduced.

[0016] Incidentally, when increasing the protrusion amount of the abrasive grains of the grinding wheel to improve the grinding power of the grinding wheel, the torque required to rotate the honing tool with the grinding wheel fixed to the tip end portion is reduced accordingly. On the other hand, when increasing the protrusion amount of the abrasive grains of the grinding wheel, the surface roughness of the inner wall of the machined hole of the workpiece when honing the workpiece using the grinding wheel increases accordingly. For example, as shown in FIG. 4(A), the torque required to rotate the honing tool with the grinding wheel according to Example A fixed to the tip end portion is smaller than the torque required to rotate the honing tool with the grinding wheel according to Example B having a smaller protrusion amount of the abrasive grains compared to Example A. On the other hand, for example, as shown in FIG. 4(B), the surface roughness of the inner wall of the machined hole of the workpiece when honing the workpiece using the grinding wheel according to Example A is larger than the surface roughness of the inner wall of the machined hole of the workpiece when honing the workpiece using the grinding wheel according to Example B having a smaller protrusion amount of the abrasive grains compared to Example A. For example, when the torque required to rotate the honing tool with the grinding wheel fixed to the tip end portion is excessively large and a torque error occurs in the honing processing apparatus equipped with the honing tool, it is necessary to adjust the protrusion amount so as to increase the protrusion amount of the abrasive grains of the grinding wheel in order to improve the grinding power of the grinding wheel. On the other hand, when the surface roughness of the inner wall of the machined hole of the workpiece when honing the workpiece using the grinding wheel exceeds the upper limit value of the surface roughness standard of the inner wall of the machined hole required for the workpiece, it is necessary to adjust the protrusion amount so as to reduce the protrusion amount of the abrasive grains of the grinding wheel. Thus, it is required to finely adjust the protrusion amount of the abrasive grains of the grinding wheel based on the capabilities of the honing processing apparatus and the standard of the surface roughness of the inner wall of the machined hole required for the workpiece.

[0017] Therefore, in the dressing method according to the present embodiment, while moving the irradiation region of the laser beam LA1 on the grinding surface Gf of the grinding wheel G, by changing the intensity of the laser beam LA1, a plurality of regions with different average values of the protrusion amounts are formed on the grinding surface Gf of the grinding wheel G. Here, for example, as shown in FIG. 5(A), the above-described plurality of regions include a first region Gf1 extending in a direction intersecting the short-side direction on the grinding surface Gf of the grinding wheel G1, and a second region Gf2 other than the first region Gf1 on the grinding surface Gf. The dressing of the grinding wheel G is performed such that the average value of the protrusion amount of the abrasive grains in the first region Gf1 is larger than the average value of the protrusion amount of the abrasive grains in the second region Gf2. Alternatively, for example, as shown in FIG. 5(B), the above-described plurality of regions include a first region Gf1 including the entire one end in the short-side direction on the grinding surface Gf of the grinding wheel G2 and extending over the entire longitudinal direction of the grinding surface Gf, and a second region Gf2 other than the first region Gf1 on the grinding surface Gf. The dressing of the grinding wheel G is performed such that the average value of the protrusion amount of the abrasive grains in the first region Gf1 is larger than the average value of the protrusion amount of the abrasive grains in the second region Gf2. Here, the ratio of the area of the first region Gf1 to the area of the entire grinding surface Gf can be 45% or more and 62% or less.

[0018] Here, a grinding wheel according to Example 1 in which the protrusion amount of abrasive grains over the entire grinding surface Gf of the grinding wheel G is made uniform, a grinding wheel according to Example 2 having a grinding surface Gf shown in Fig. 5(A), and a grinding wheel according to Example 3 having a grinding surface Gf shown in Fig. 5(B) are used to compare the surface roughness of the inner wall of the machined hole of the workpiece when honing the workpiece. Here, dressing was performed so that the average value of the protrusion amount of abrasive grains over the entire grinding surface Gf of the grinding wheel according to Example 1 would be the same as the average value of the protrusion amount of abrasive grains in the first region Gf1 of the grinding surface Gf of the grinding wheels according to Examples 2 and 3. Also, dressing was performed so that the average values of the protrusion amounts of abrasive grains in the second region Gf2 of the grinding wheels according to Examples 2 and 3 would be the same as each other. As shown in Fig. 6, the surface roughness of the inner wall of the machined hole of the workpiece when honing the workpiece using the grinding wheels according to Examples 2 and 3 was smaller than the surface roughness of the inner wall of the machined hole of the workpiece when honing the workpiece using the grinding wheel according to Example 1. Also, the variation in the surface roughness of the inner wall of the machined hole of the workpiece for each machining cycle when honing the workpiece using the grinding wheel according to Example 3 was smaller than the variation in the surface roughness of the inner wall of the machined hole of the workpiece for each machining cycle when honing the workpiece using the grinding wheel according to Example 2. That is, by making the protrusion amount of some of the abrasive grains on the grinding surface smaller as in the grinding wheels according to Examples 2 and 3, compared to the case where the protrusion amount of abrasive grains over the entire grinding surface is made larger as in the grinding wheel according to Example 1, it was found that the so-called surface roughness of the inner wall of the machined hole of the workpiece when honing the workpiece using the grinding wheel is improved.

[0019] Thus, by forming regions with different protrusion amounts of abrasive grains within the grinding surface of the grinding wheel, it is possible to finely adjust the surface roughness of the inner wall of the machined hole of the workpiece when honing the workpiece using the grinding wheel, or the torque required when rotating a honing tool having the grinding wheel fixed to its tip.

[0020] Further, a grinding wheel according to Example 4 in which the protrusion amount of abrasive grains over the entire grinding surface Gf of the grinding wheel G is made uniform, and grinding wheels according to Examples 5 and 6 having the grinding surface Gf shown in FIG. 5(B) are used to compare the surface roughness of the inner wall of the machined hole of the workpiece when honing the workpiece. Here, dressing was performed so that the average value of the protrusion amount of abrasive grains over the entire grinding surface Gf of the grinding wheel according to Example 4 would be the same as the average value of the protrusion amount of abrasive grains in the first region Gf1 of the grinding surface Gf of the grinding wheels according to Examples 5 and 6. Also, the grinding wheel according to Example 5 was dressed so that the ratio of the first region Gf1 to the entire grinding surface would be 45%, and the grinding wheel according to Example 6 was dressed so that the ratio of the first region Gf1 to the entire grinding surface would be 62%. As shown in FIG. 7, the surface roughness of the inner wall of the machined hole of the workpiece when honing the workpiece using the grinding wheels according to Examples 5 and 6 was smaller than the surface roughness of the inner wall of the machined hole of the workpiece when honing the workpiece using the grinding wheel according to Example 4. Also, the surface roughness of the inner wall of the machined hole of the workpiece when honing the workpiece using the grinding wheel according to Example 5 was smaller than the surface roughness of the inner wall of the machined hole of the workpiece when honing the workpiece using the grinding wheel according to Example 6. In the honing process using the grinding wheels according to Examples 5 and 6, when the grinding wheel G slides relative to the workpiece W as shown by the arrows in FIGS. 8(A) and 8(B), the second region Gf2 of the grinding surface Gf with a relatively small protrusion amount of the abrasive grains AB sweeps the machined surface of the workpiece W ground by the first region Gf1 of the grinding surface Gf with a relatively large protrusion amount of the abrasive grains AB, and it is considered that the surface roughness of the machined surface of the workpiece W is reduced. And since the area of the second region Gf2 of the grinding wheel G according to Example 5 shown in FIG. 8(A) is larger than the area of the second region Gf2 of the grinding wheel G according to Example 6 shown in FIG. 8(B), the surface roughness of the machined surface of the portion surrounded by the broken line in FIG. 8(A) is smaller than that of the machined surface of the portion surrounded by the broken line in FIG. 8(B). That is, by changing the area ratio between the first region Gf1 and the second region Gf2 on the grinding surface Gf of the grinding wheel G, the properties of the machined surface of the workpiece W can be controlled.

[0021] As described above, according to the dressing method according to the present embodiment, by changing the intensity of the laser beam while moving the irradiation area of the laser beam on the grinding surface Gf of the grinding wheel G, a plurality of areas with different protruding amounts of abrasive grains are formed on the grinding surface of the grinding wheel G. Thereby, since the grinding performance of the grinding wheel G can be changed by changing the area ratio of each of the plurality of areas on the grinding surface Gf of the grinding wheel G, the grinding performance of the grinding wheel G can be finely adjusted.

[0022] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the configurations of the above-described embodiments. For example, a plurality of first regions Gf1 may be formed in the grinding surface Gf of the grinding wheel G so as to extend along the longitudinal direction of the grinding surface Gf.

[0023] In the embodiment, an example has been described in which the dressing device includes a head attitude changing unit 13 that changes the radiation direction of the laser beam LA1 by changing the attitude of the laser head 12. However, the present invention is not limited to this. For example, as shown by the arrow AR2001 in FIG. 9, the dressing device moves the laser head 12 in a direction parallel to the grinding surface Gf of the grinding wheel G held by the grinding wheel holding unit 11, so that the laser beam LA1 on the grinding surface Gf of the grinding wheel G is irradiated. It may be provided with a head transport unit 2013 for moving the irradiation area. The head transport unit 2013 includes a first transport unit 2131 that transports the laser head 12 along a first direction parallel to the grinding surface Gf, and the laser head 12 and the first transport unit 2131 along a second direction parallel to the grinding surface Gf and orthogonal to the aforementioned first direction. And a second transport unit 2132 for transporting the laser head 12.

[0024] In the embodiment, an example has been described in which the laser head 12 condenses the laser beam LA1 so that the area of the irradiation region on the grinding surface Gf is at least smaller than the area of the grinding surface Gf, and irradiates the grinding surface Gf. However, the present invention is not limited to this. For example, the laser head 12 may condense the laser beam LA1 so that the area of the irradiation region is substantially the same as the area of the entire grinding surface Gf. Then, by adjusting how the intensity of the laser beam LA1 changes, the protrusion amount of the abrasive grains on the entire grinding surface Gf may be adjusted. Specifically, the laser head 12 repeats the irradiation of the entire grinding surface Gf with the laser beam LA1 at the maximum intensity and the irradiation of the entire grinding surface Gf with the laser beam LA1 at an intensity approximately half of the maximum intensity, and the ratio of the irradiation time at the maximum intensity and the irradiation time at an intensity approximately half of the maximum intensity in one repetition cycle are appropriately changed to adjust the protrusion amount of the abrasive grains.

[0025] As described above, the embodiments and modified examples of the present invention have been described, but the present invention is not limited to these. The present invention includes those in which the embodiments and modified examples are appropriately combined, and those in which appropriate changes are made thereto.

Industrial Applicability

[0026] The present invention is suitable as a dressing method for a grindstone fixed to the tip of a honing tool.

Explanation of Signs

[0027] 11: Grindstone holding part, 12: Laser head, 13: Head posture changing part, 21: Control part, 22: Terminal device, 2013: Head conveyance part, 2131: First conveyance unit, 2132: Second conveyance unit, AB: Abrasive grain, G, G1, G2: Grindstone, Gf: Grinding surface, Gf1: First region, Gf2: Second region, LA1: Laser beam, W: Work

Claims

Claim 1 A dressing method for adjusting the protrusion amount of abrasive grains by holding a grinding wheel formed by binding abrasive grains with a binder in a state where the grinding surface of the grinding wheel is exposed, and irradiating the grinding surface with a laser beam to melt and evaporate the binder, comprising: while condensing the laser beam so that the area of the irradiation region irradiated with the laser beam on the grinding surface is at least smaller than the area of the grinding surface and irradiating the grinding surface, and while moving the irradiation region on the grinding surface, by changing the intensity of the laser beam, forming a plurality of regions on the grinding surface having different average values of the protrusion amount; A dressing method. Claim 2 A dressing method for adjusting the protrusion amount of abrasive grains by holding a grinding wheel formed by binding abrasive grains with a binder in a state where the grinding surface of the grinding wheel is exposed, and irradiating the grinding surface with a laser beam to melt and evaporate the binder, comprising: forming a plurality of regions on the grinding surface having different average values of the protrusion amount by changing at least one of the irradiation region of the laser beam on the grinding surface and the intensity of the laser beam; A dressing method. Claim 3 The grinding wheel has a longitudinally long grinding surface in plan view, and is mounted on the tip of a long honing tool for honing the inner surface of a work machining hole such that the longitudinal direction of the grinding surface is along the longitudinal direction of the honing tool. By rotating the honing tool about the central axis along the longitudinal direction of the honing tool in a state where the grinding surface is in contact with the inner surface of the machining hole, the grinding surface slides in the short side direction to grind the inner surface of the machining hole. The plurality of regions are composed of a first region extending in a direction intersecting the short side direction on the grinding surface and a second region other than the first region on the grinding surface. The average value of the protrusion amount in the first region is larger than the average value of the protrusion amount in the second region. The dressing method according to claim 1 or 2. Claim 4 The grinding stone has a long grinding surface in plan view, and is mounted on the tip of a long honing tool for honing the inner surface of a work machining hole such that the longitudinal direction of the grinding surface is along the longitudinal direction of the honing tool. By rotating the honing tool about the central axis along the longitudinal direction of the honing tool with the grinding surface in contact with the inner surface of the machining hole, the grinding surface slides in the short-side direction to grind the inner surface of the machining hole. The plurality of regions are composed of a first region that includes the entire one end in the short-side direction on the grinding surface and extends over the entire longitudinal direction of the grinding surface, and a second region other than the first region on the grinding surface. The average value of the protruding amount in the first region is larger than the average value of the protruding amount in the second region. The dressing method according to claim 1 or 2.

5. A grinding stone holding part that holds a grinding stone formed by binding abrasive grains with a binder in a state where the grinding surface of the grinding stone is exposed. A laser head that condenses laser light so that the area of the irradiation region on the grinding surface irradiated with the laser light is at least smaller than the area of the grinding surface, and irradiates the grinding surface. A head posture changing part that changes the posture of the laser head to change the radiation direction of the laser light, thereby moving the irradiation region on the grinding surface. A control part that controls the head posture changing part to move the irradiation region on the grinding surface, and controls the laser head to change the intensity of the laser light, thereby forming a plurality of regions on the grinding surface with different average values of the protruding amount of the abrasive grains. Dressing device.

6. A grinding stone holding part that holds a grinding stone formed by binding abrasive grains with a binder in a state where the grinding surface of the grinding stone is exposed. A laser head that irradiates the grinding surface with laser light. A head posture changing part that changes the posture of the laser head to change the radiation direction of the laser light, thereby changing the irradiation region of the laser light on the grinding surface. A control part that performs at least one of controlling the head posture changing part to change the irradiation region on the grinding surface and controlling the laser head to change the intensity of the laser light, thereby forming a plurality of regions on the grinding surface with different average values of the protruding amount of the abrasive grains. Dressing device.

7. A grinding stone formed by binding abrasive grains with a binder, having a long grinding surface in plan view, and mounted at the tip of a long honing tool for honing the inner surface of a machining hole of a workpiece such that the longitudinal direction of the grinding surface is along the longitudinal direction of the honing tool. By rotating the honing tool about a central axis along the longitudinal direction of the honing tool with the grinding surface in contact with the inner surface of the machining hole, the grinding stone slides in the short-side direction of the grinding surface to grind the inner surface of the machining hole, The average value of the protrusion amount of the abrasive grains in a first region extending in a direction intersecting the short-side direction of the grinding surface is larger than the average value of the protrusion amount in a second region other than the first region on the grinding surface. Grinding stone.

8. A grinding stone formed by binding abrasive grains with a binder, having a long grinding surface in plan view, and mounted at the tip of a long honing tool for honing the inner surface of a machining hole of a workpiece such that the longitudinal direction of the grinding surface is along the longitudinal direction of the honing tool. By rotating the honing tool about a central axis along the longitudinal direction of the honing tool with the grinding surface in contact with the inner surface of the machining hole, the grinding stone slides in the short-side direction of the grinding surface to grind the inner surface of the machining hole, The average value of the protrusion amount of the abrasive grains in a first region including the entire one end in the short-side direction of the grinding surface and extending over the entire longitudinal direction of the grinding surface is larger than the average value of the protrusion amount in a second region other than the first region on the grinding surface. Grinding stone.

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