Workpiece processing device, grinding stone, and workpiece processing method

Abstract

The grinding stone (5) has a convex grinding portion (5b) on the outer periphery and is rotatable and disc-shaped. The cross-sectional shape of the convex grinding portion (5b) passing through the rotation axis (6) of the grinding stone (5) is convex toward the outer periphery and has arc-shaped portions (5e) at both ends at least in the thickness direction. In order to use the grinding stone (5) to form a disc-shaped workpiece (2) into a desired cross-sectional shape, the workpiece (2) and the grinding stone (5) are arranged parallel to each other. While the grinding stone (5) is rotated and the workpiece (2) is rotated around a rotation axis (3) parallel to the rotation axis (6) of the grinding stone (5), the grinding stone (5) is moved relative to the workpiece (2) according to a movement condition calculated based on the curvature radius of the arc-shaped portion (5e) of the grinding stone (5) so that the contact portion of the convex grinding portion (5b) and the workpiece (2) moves along the desired cross-sectional shape of the workpiece (2). The curvature radius of the arc-shaped portion (5e) of the grinding stone (5) is at least (10) times the thickness of the workpiece (2).

Description

Technical Field

[0001] The present invention relates to a workpiece processing device, a grinding stone and a workpiece processing method. Background Art

[0002] In the past, in order to perform chamfering on the outer periphery of a disc-shaped workpiece (workpiece) such as a semiconductor wafer, a grinding stone was pressed against the outer periphery of the workpiece to perform grinding. In order to improve the accuracy of the shape and size of the chamfered portion of the workpiece, there is a method as follows: a groove (forming groove) with a shape and size corresponding to the finished shape of the workpiece is formed on the outer periphery of the grinding stone, the outer periphery of the workpiece is inserted into the groove and the workpiece is rotated, and the outer periphery of the workpiece is ground using the inner circumferential surface of the groove. However, in this method, the grinding stone needs to be replaced every time the shape and size of the workpiece to be manufactured changes, which is not suitable for small-scale production of multiple varieties. In addition, when the chamfering process is repeatedly performed, the inner circumferential surface of the groove on the outer periphery of the grinding stone wears or breaks, causing the shape and size of the groove to change, thereby reducing the accuracy of the chamfering process of the workpiece. Therefore, after the chamfering process of the workpiece has been performed for a long period of time, the grinding stone needs to be replaced or reshaped.

[0003] In order to replace or reshape the grinding stone as needed, the methods described in Patent Documents 1 and 2 (Japanese Patent Application Publication Nos. 2005-153085 and 2007-165712) prefabricate a main grinding stone with a groove corresponding to the finished shape of the workpiece. The outer periphery of the grinding stone material is brought into contact with the inner periphery of the groove of the main grinding stone for grinding, thereby producing a dressing grinding stone (dressing piece) as a profile. Furthermore, the grinding stone material abuts the outer periphery of the dressing grinding stone, forming a groove identical to that of the main grinding stone. This allows the shape of the grinding stone used for actual chamfering of the workpiece to be adjusted (shaped). The dressing grinding stone is made of a harder material (e.g., a GC grinding stone) than the grinding stone used for chamfering (e.g., a resin-bonded grinding stone), while the main grinding stone is made of a harder material (e.g., a metal-bonded grinding stone). This process of reshaping the grinding stone using the dressing grinding stone is called dressing.

[0004] In Patent Documents 1 and 2, in addition to the method of chamfering using the formed groove of a disc-shaped grinding stone arranged parallel to the disc-shaped workpiece, a method of chamfering the workpiece using the groove of a disc-shaped grinding stone arranged obliquely in the tangential direction of the outer periphery of the disc-shaped workpiece (a spiral processing method) is also suggested. The spiral chamfering method is also described in Patent Document 3. In the method described in Patent Document 3 (Japanese Patent Application Laid-Open No. 5-152259), the grinding stone arranged obliquely in the tangential direction of the outer periphery of the workpiece is formed with a concave groove on the outer periphery and has an inclined surface facing inward. The inclined surface is brought into contact with the outer periphery of the workpiece to perform grinding. Patent document 4 (Japanese Patent Application Laid-Open No. 2007-044817) discloses a processing method for grinding a disc-shaped workpiece using a disc-shaped grinding stone arranged parallel to the disc-shaped workpiece, and then performing more precise grinding in a spiral manner using a disc-shaped grinding stone arranged obliquely in a tangential direction with respect to the outer circumference of the disc-shaped workpiece, as well as a dressing grinding stone and a dressing method for dressing the grinding stone for precision grinding in the spiral manner.

[0005] When chamfering a workpiece using a grindstone tilted relative to the tangential direction of the workpiece's periphery, as described in Patent Documents 1 to 4, grinding is performed with the inner circumferential surface of the grooves provided on the periphery of the grindstone in contact with the periphery of the workpiece extended. Furthermore, grinding is performed while the workpiece is rotated at a low speed, thereby reducing the surface roughness of the chamfered portion of the workpiece. This facilitates subsequent finishing grinding.

[0006] Patent Document 5 (Japanese Patent Application Laid-Open No. 11-207585) discloses a method for chamfering a workpiece using a grindstone having grooves on its outer periphery whose dimensions in the thickness direction are larger than the thickness of the workpiece, and bringing the inner circumferential surface of the grooves of the grindstone into contact with the outer periphery of the workpiece. Patent Document 5 also discloses a method for chamfering a workpiece using a grindstone that is thicker than the workpiece and has no grooves on its outer periphery but a convex cross-sectional shape of its outer periphery, and bringing the inclined surface of a portion of the convex portion of the grindstone into contact with the outer periphery of the workpiece.

[0007] In the method described in patent document 6 (Japanese Patent Application Publication No. 2000-317789), a disc-shaped grinding stone is arranged in a manner orthogonal to a disc-shaped workpiece. The workpiece can rotate around a rotation axis located at the center of its top view shape. The grinding stone can rotate around a rotation axis orthogonal to the rotation axis of the workpiece and can move in a direction perpendicular to its rotation axis (a direction parallel to the disc-shaped workpiece) and in a direction parallel to the rotation axis (a direction orthogonal to the disc-shaped workpiece). While the workpiece is being rotated, the grinding stone is brought close to the workpiece while rotating, and the grinding stone is moved while the outer periphery of the rotating grinding stone is brought into contact with the outer periphery of the workpiece rotating in a direction orthogonal to the rotation direction of the grinding stone, thereby performing chamfering of the workpiece. Such a processing step is called contour processing.

[0008] In the method described in Patent Document 7 (Japanese Patent Application Laid-Open No. 2008-034776), a cup grindstone is positioned perpendicular to a disk-shaped workpiece. Similar to Patent Document 6, the cup grindstone is brought close to the workpiece while the workpiece is rotating. The cup grindstone is moved while the cup-shaped front end surface of the rotating cup grindstone contacts the outer periphery of the workpiece, which is rotating in a direction perpendicular to the rotational direction of the cup grindstone, thereby chamfering the workpiece.

[0009] Patent Document 8 (Japanese Patent Application Laid-Open No. 2014-37014) discloses a method of performing chamfering similar to Patent Document 6 using two disk-shaped grindstones and a method of performing chamfering similar to Patent Document 7 using two cup-shaped grindstones.

[0010] In the method described in Patent Document 9 (Japanese Patent Application Publication No. 2017-154240), a large and double-structured cup-shaped first grindstone having a grindstone element (cup shape) on the inner circumference and a grindstone element (cup shape) on the outer circumference for grinding more precisely than the grinding performed by the grindstone element on the inner circumference, and a cup-shaped second grindstone are used to process the outer circumference of a workpiece.

[0011] Prior art literature

[0012] Patent Literature

[0013] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-153085

[0014] Patent Document 2: Japanese Patent Application Laid-Open No. 2007-165712

[0015] Patent Document 3: Japanese Patent Application Laid-Open No. 5-152259

[0016] Patent Document 4: Japanese Patent Application Laid-Open No. 2007-044817

[0017] Patent Document 5: Japanese Patent Application Laid-Open No. 11-207585

[0018] Patent Document 6: Japanese Patent Application Laid-Open No. 2000-317789

[0019] Patent Document 7: Japanese Patent Application Laid-Open No. 2008-034776

[0020] Patent Document 8: Japanese Patent Application Laid-Open No. 2014-37014

[0021] Patent Document 9: Japanese Patent Application Laid-Open No. 2017-154240 Summary of the Invention

[0022] Problems to be solved by the invention

[0023] It is not easy to precisely form grooves for chamfering a workpiece on the outer periphery of a grindstone tilted tangentially to the workpiece's periphery, as described in Patent Documents 1 to 4. To form a desired chamfered shape on a workpiece, the inner circumferential surface of the groove must contact the workpiece's periphery at an appropriate angle and for an appropriate contact length. In grindstones tilted tangentially to the workpiece's periphery, it is difficult to form grooves with inner circumferential surfaces that precisely contact the workpiece's periphery at an appropriate angle and for an appropriate contact length. In particular, when a dressing grindstone is rotated by a drive unit that rotates the workpiece or a drive unit that rotates the grinding stone used to grind the workpiece, it is difficult to precisely form grooves that enable a good chamfering process while tilted tangentially to the workpiece's periphery. Therefore, a method that facilitates dressing is desired. Furthermore, if the shape or size of the chamfered portion of the workpiece to be produced changes, the shape of the grooves in the main grinding stone used to make the dressing grindstone also needs to be changed, making the process complex.

[0024] When machining a workpiece using a grindstone tilted relative to the workpiece's outer circumference, the shape and dimensions of the inner circumferential surface of the groove cannot be easily changed, making it difficult to make fine corrections to achieve the desired machined shape. Consequently, when manufacturing a wafer having an orientation flat portion as a workpiece, it is impossible to accurately form the orientation flat portion using a grindstone tilted relative to the workpiece's outer circumference, which primarily forms the arc-shaped portion of the workpiece's outer circumference. Consequently, the groove for forming the orientation flat portion must be formed separately from the groove for forming the arc-shaped portion, complicating grindstone manufacture and increasing machining time due to the use of two separate grooves.

[0025] In the method described in Patent Document 5, the inclined surface of the grinding stone, which is part of the inner peripheral surface of the groove, or the inclined surface of the grinding stone, which is part of the convex portion of the outer periphery, is brought into contact with the outer periphery of the workpiece to perform grinding. The workpiece is relatively moved along the inclined surface of the grinding stone to grind the outer periphery of the workpiece, so that the shape of the outer periphery of the ground workpiece becomes a shape corresponding to the inclined surface of the grinding stone. Since the angle of the inclined surface of the outer periphery of the grinding stone cannot be arbitrarily changed, it is difficult to form the chamfered portion of the workpiece into an arbitrary shape. In addition, in the chamfered portions on both sides of the workpiece, the straight portion at the front end, and the curved portion between the straight portion and the chamfered portion, the workpiece is ground while being relatively reciprocated (traversed) along the grinding stone, so the processing is complicated and the processing time is long.

[0026] In the method described in Patent Document 6, the disc-shaped grinding stone is arranged orthogonally to the disc-shaped workpiece. Therefore, when using a large grinding stone, the grinding stone could interfere with the workpiece support and drive mechanisms (e.g., suction tables and rotating mechanisms). Therefore, to ensure stable support and smooth drive of the workpiece, a small grinding stone is used instead of a large one. This results in poor processing efficiency and increased processing time. Furthermore, when chamfering the same workpiece, a small grinding stone spends more time grinding the same portion of the workpiece in contact with the outer periphery than a large one, resulting in a shorter grinding stone life. Furthermore, the workpiece is moved so that the contact portion with the grinding stone follows a trajectory that aligns with the desired cross-sectional shape. However, the workpiece must be fully ground before it is moved. Therefore, to achieve high efficiency, the workpiece must be rotated at high speed. This high-speed grinding process causes streaks on the outer surface of the workpiece, extending along the thickness of the workpiece. The grinding stone rotates in a direction perpendicular to the workpiece's rotational direction, resulting in a high surface roughness of the ground portion. Even if a more precise finishing step is performed after this grinding step, the presence of striations perpendicular to the workpiece's rotational direction makes grinding difficult. Particularly, inclined portions of the workpiece are difficult to grind in the subsequent precise grinding step, potentially resulting in insufficient grinding and the presence of striations.

[0027] In the method described in Patent Document 7, the cup-shaped grinding stone is complicated to manufacture and difficult to dress. In addition, it is not easy to arrange and drive the cup-shaped grinding stone so that the cup-shaped front end surface contacts the outer periphery of the workpiece properly, and the mechanism for supporting and driving the cup-shaped grinding stone is complex.

[0028] In addition to the problems of the methods described in Patent Documents 6 and 7, the method described in Patent Document 8 has the following problems: since two grinding stones are driven simultaneously, the device becomes complicated, and differences in size and shape are easily generated between the two grinding stones, making it difficult to stably perform high-precision chamfering.

[0029] In the method described in Patent Document 9, the shape of the first grinding stone is extremely complex, making its manufacture complicated. Furthermore, since the workpiece rotates about two separate axes, the mechanism for supporting and driving the workpiece is also complex. Consequently, the machining apparatus for implementing the method described in Patent Document 9 is extremely complex.

[0030] The object of the present invention is to provide a workpiece processing device, a grinding stone, and a workpiece processing method that can easily perform chamfering of a workpiece efficiently and accurately, have a simple mechanism for supporting and driving the workpiece and the grinding stone, and can easily perform shaping of the grinding stone.

[0031] Solutions to Problems

[0032] The workpiece processing device of the present invention is used to form a circular plate-shaped workpiece into a desired cross-sectional shape, and the workpiece processing device is characterized in that the workpiece processing device includes a workpiece supporting mechanism for supporting the workpiece, a circular plate-shaped grinding stone arranged parallel to the workpiece, and a grinding stone supporting mechanism for supporting the grinding stone, the workpiece supporting mechanism rotates the workpiece, and the grinding stone supporting mechanism rotates the grinding stone, the rotation axis serving as the center of rotation of the workpiece performed by the workpiece supporting mechanism and the rotation axis serving as the center of rotation of the grinding stone performed by the grinding stone supporting mechanism are parallel to each other, the grinding stone has a convex grinding portion on the outer periphery, the cross-sectional shape of the convex grinding portion in the cross section passing through the rotation axis of the grinding stone is convex toward the outer periphery, and has a shape having arc-shaped portions at both ends at least in the thickness direction, the grinding stone and the workpiece can be relatively moved in a manner of approaching or separating from each other by the grinding stone supporting mechanism or the workpiece supporting mechanism, and the grinding stone supporting mechanism or the workpiece supporting mechanism The workpiece support mechanism moves the grinding stone relative to the workpiece according to a movement condition calculated based on the curvature radius of the arcuate portion of the grinding stone so that a contact portion between the convex grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece. The convex grinding portion and a rectangular grinding portion having a surface facing the workpiece and having a straight line parallel to the thickness direction of the grinding stone in a cross section along the rotation axis are arranged on the outer periphery of the grinding stone in the thickness direction. The rectangular grinding portion of the grinding stone is a portion that contacts the outer periphery of the workpiece and grinds the workpiece so as to reduce the radius of the workpiece as the grinding stone moves from the outer side to the inner side in the radial direction of the workpiece. The curvature radius of the arcuate portion of the grinding stone is at least 10 times the thickness of the workpiece so that the arcuate portion of the grinding stone contacts the workpiece with substantially no gap between the arcuate portion of the grinding stone and the chamfered portion of the desired cross-sectional shape of the workpiece.

[0033] In addition, another workpiece processing device of the present invention is used to form a circular plate-shaped workpiece into a desired cross-sectional shape, and the workpiece processing device is characterized in that the workpiece processing device has a workpiece supporting mechanism for supporting the workpiece, a circular plate-shaped grinding stone arranged parallel to the workpiece, and a grinding stone supporting mechanism for supporting the grinding stone, the workpiece supporting mechanism rotates the workpiece, and the grinding stone supporting mechanism rotates the grinding stone, the rotation axis serving as the center of rotation of the workpiece performed by the workpiece supporting mechanism and the rotation axis serving as the center of rotation of the grinding stone performed by the grinding stone supporting mechanism are parallel to each other, the grinding stone has a convex grinding portion on the outer periphery, the cross-sectional shape of the convex grinding portion in the cross section passing through the rotation axis of the grinding stone is convex toward the outer periphery, and has a shape having arc-shaped portions at both ends at least in the thickness direction, the grinding stone and the workpiece can be relatively moved in a manner of approaching or separating from each other by the grinding stone supporting mechanism or the workpiece supporting mechanism, and the grinding stone supporting mechanism or the workpiece supporting mechanism The mechanism moves the grinding stone relative to the workpiece according to a movement condition calculated based on the curvature radius of the arc-shaped portion of the grinding stone so that the contact portion between the convex grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece. In addition to the grinding stone having the convex grinding portion, the workpiece processing device further includes a circular plate-shaped grooved grinding stone arranged obliquely with respect to a tangential direction of the outer periphery of the workpiece and used for grinding more precisely than that performed by the convex grinding portion of the grinding stone, and a grooved grinding stone support mechanism for supporting the grooved grinding stone. The grooved grinding stone support mechanism rotates the grooved grinding stone. The workpiece processing device further includes a dressing grinding stone that can be mounted on the workpiece support mechanism in place of the workpiece. The dressing grinding stone is formed into an outer shape by being relatively moved relative to the grinding stone by the grinding stone support mechanism or the workpiece support mechanism according to the movement condition. The grooved grinding stone forms or shapes the grooves by being pressed against the dressing grinding stone and transferring the outer shape of the dressing grinding stone.

[0034] The grinding stone of the present invention is included in a workpiece processing device, wherein the workpiece processing device has a workpiece supporting mechanism for supporting a circular plate-shaped workpiece, the circular plate-shaped grinding stone arranged parallel to the workpiece, and a grinding stone supporting mechanism supporting the grinding stone, wherein the workpiece supporting mechanism rotates the workpiece, and the grinding stone supporting mechanism rotates the grinding stone, wherein a rotation axis serving as a center of rotation of the workpiece performed by the workpiece supporting mechanism and a rotation axis serving as a center of rotation of the grinding stone performed by the grinding stone supporting mechanism are parallel to each other, the grinding stone has a convex grinding portion on its outer periphery, a cross-sectional shape of the convex grinding portion in a cross section passing through the rotation axis of the grinding stone is convex toward the outer periphery, and has a shape having arc-shaped portions at both ends at least in a thickness direction, the grinding stone and the workpiece can be relatively moved in a manner of approaching or separating from each other by the grinding stone supporting mechanism or the workpiece supporting mechanism, and the grinding stone supporting mechanism or the workpiece supporting mechanism is arranged so that the convex grinding portion The grinding stone is moved relative to the workpiece in a manner such that a contact portion of the grinding portion and the workpiece moves along a desired cross-sectional shape of the workpiece based on a movement condition calculated from a radius of curvature of the arcuate portion of the grinding stone, and the workpiece processing device is configured to form the workpiece into the desired cross-sectional shape. The grinding stone is characterized in that a cross-sectional shape of the convex grinding portion in a cross section passing through the rotation axis of the grinding stone is a shape having a pair of arcuate portions located at both ends in a thickness direction and a straight portion located between the pair of arcuate portions, the straight portion being a portion having a coarser grinding stone grain size than the arcuate portions, the arcuate portion being a portion used for grinding more precisely than grinding performed by the straight portion, and the radius of curvature of the arcuate portion being at least 10 times the thickness of the workpiece so that the arcuate portion abuts against the workpiece with substantially no gap between the arcuate portion and the chamfered portion of the desired cross-sectional shape of the workpiece.

[0035] The workpiece processing method of the present invention is used to form a circular plate-shaped workpiece into a desired cross-sectional shape using a grinding stone, wherein the grinding stone has a convex grinding portion on the outer periphery and is rotatable and has a circular plate shape, the cross-sectional shape of the convex grinding portion in the cross section passing through the rotation axis of the grinding stone is convex toward the outer periphery, and has a shape having arc-shaped portions at both ends at least in the thickness direction, and the workpiece processing method is characterized in that it includes: the steps of arranging the workpiece and the grinding stone parallel to each other; and while rotating the grinding stone and rotating the workpiece around a rotation axis parallel to the rotation axis of the grinding stone, rotating the workpiece in such a manner that the convex grinding portion is aligned with the rotation axis. The step of moving the grinding stone relative to the workpiece in such a manner that the contact portion of the workpiece moves along the desired cross-sectional shape of the workpiece based on a movement condition calculated based on the curvature radius of the circular arc portion of the grinding stone. The step of moving the grinding stone relative to the workpiece includes: while rotating the workpiece and the grinding stone, causing the circular arc portion of the convex grinding portion of the grinding stone to move relative to the workpiece in a curved manner at a pre-calculated angle from the outer peripheral end face of the workpiece toward one side according to the movement condition, thereby grinding the outer peripheral portion of the one side side of the workpiece; and causing the grinding stone to move along the outer peripheral end face of the workpiece. The grinding wheel is moved relative to the workpiece from the one surface side to the other surface side; and while the workpiece and the grinding stone are rotated, the arc-shaped portion of the convex grinding portion of the grinding stone is moved relative to the workpiece in a curved line at a pre-calculated angle from the outer peripheral end face of the workpiece toward the other surface according to the movement conditions, thereby grinding the outer peripheral portion of the other surface side of the workpiece. When the outer peripheral portion of the one surface side or the other surface side of the workpiece is roughly ground, while the workpiece and the grinding stone are rotated, the arc-shaped portion of the convex grinding portion of the grinding stone is moved from the outer peripheral end face of the workpiece toward the other surface. After the end face is relatively moved in a curved line relative to the workpiece at a pre-calculated angle according to the movement condition with the end face toward the one face or the other face, the relative movement of the grinding stone relative to the workpiece is stopped. When performing precision grinding of the outer peripheral portion of the one face side or the other face side of the workpiece, while the workpiece and the grinding stone are rotated, the arc-shaped portion of the convex grinding portion of the grinding stone is relatively moved in a curved line relative to the workpiece from the outer peripheral end face of the workpiece toward the one face or the other face at a pre-calculated angle according to the movement condition, and then the grinding stone is relatively moved in a straight line relative to the workpiece.

[0036] The workpiece processing method of the present invention is used to form a circular plate-shaped workpiece into a desired cross-sectional shape using a grinding stone, the grinding stone having a convex grinding portion on the outer periphery and being rotatable and circular plate-shaped, the cross-sectional shape of the convex grinding portion in the cross section passing through the rotation axis of the grinding stone being convex toward the outer periphery, and having arc-shaped portions at both ends at least in the thickness direction, the workpiece processing method is characterized in that it includes: the steps of arranging the workpiece and the grinding stone parallel to each other; and the steps of moving the grinding stone relative to the workpiece according to movement conditions calculated based on the curvature radius of the arc-shaped portion of the grinding stone in such a manner that the contact portion between the convex grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece while rotating the grinding stone and rotating the workpiece around a rotation axis parallel to the rotation axis of the grinding stone, the workpiece processing method includes utilizing the flow of liquid or gas The temperature of the rotating shaft of the workpiece is adjusted, and before processing the workpiece, a preliminary rotation action is performed to rotate the rotating shaft serving as the rotation center of the workpiece in a state where the workpiece is not mounted. In the preliminary rotation action, high-speed rotation at the same speed as the high-speed rotation of the workpiece during processing by the grindstone and low-speed rotation at the same speed as the low-speed rotation of the workpiece during processing by the grindstone are repeated alternately, and the ratio of the duration of the high-speed rotation to the duration of the low-speed rotation in the preliminary rotation action is made consistent with the ratio of the duration of the high-speed rotation to the duration of the low-speed rotation of the workpiece during processing by the grindstone, and the duration of the high-speed rotation and the duration of the low-speed rotation in the preliminary rotation action are made shorter than the duration of the high-speed rotation and the duration of the low-speed rotation of the workpiece during processing by the grindstone, respectively.

[0037] The workpiece processing method of the present invention is used to form a circular plate-shaped workpiece into a desired cross-sectional shape using a grinding stone, wherein the grinding stone has a convex grinding portion on the outer periphery and is rotatable and has a circular plate shape, wherein the cross-sectional shape of the convex grinding portion in a cross section passing through the rotation axis of the grinding stone is convex toward the outer periphery and has a shape having arc-shaped portions at both ends at least in the thickness direction. The workpiece processing method is characterized in that it includes: the steps of arranging the workpiece and the grinding stone parallel to each other; and rotating the grinding stone and rotating the workpiece around a rotation axis parallel to the rotation axis of the grinding stone. At the same time, the step of moving the grinding stone relative to the workpiece according to a movement condition calculated based on the curvature radius of the circular arc portion of the grinding stone in such a manner that the contact portion of the convex grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece, wherein, in addition to the grinding stone, a circular plate-shaped grooved grinding stone is arranged obliquely with respect to the tangential direction of the outer periphery of the workpiece, after the convex grinding portion of the grinding stone is brought into contact with the workpiece to grind the workpiece, the inner peripheral surface of the groove of the grooved grinding stone is brought into contact with the workpiece to perform grinding compared with the convex grinding portion. The workpiece processing method comprises the steps of arranging a circular plate-shaped dressing grindstone in parallel with the grinding stone before arranging the workpiece and the circular plate-shaped grinding stone in parallel with each other, rotating the grinding stone and rotating the dressing grindstone around a rotation axis parallel to the rotation axis of the grinding stone, moving the grinding stone relative to the dressing grindstone to form the outer shape of the dressing grindstone, and pressing the material of the grooved grinding stone against the dressing grindstone to transfer the outer shape of the dressing grindstone to form or shape the grooves, and transferring the outer shape of the dressing grindstone to the dressing grindstone. In the step of forming or shaping the groove by adjusting the outer shape of the grinding stone, the groove is formed into a shape predetermined in order to form the workpiece abutting the inner peripheral surface of the groove into the desired cross-sectional shape. In the step of forming the outer shape of the dressing grinding stone, a movement condition is calculated in advance based on the curvature radius of the arc-shaped portion of the grinding stone so that the contact portion between the convex grinding portion of the grinding stone and the dressing grinding stone moves along a shape corresponding to the predetermined shape of the groove. In the step of forming the outer shape of the dressing grinding stone, the dressing grinding stone is moved relative to the grinding stone according to the movement condition.

[0038] Effects of the Invention

[0039] According to the present invention, a workpiece processing device, a grinding stone, and a workpiece processing method can be provided, which can easily perform chamfering of a workpiece efficiently and accurately, have a simple mechanism for supporting and driving the workpiece and the grinding stone, and can easily perform shaping of the grinding stone. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a front view schematically showing a workpiece processing apparatus according to a first embodiment of the present invention.

[0041] Figure 2 It shows Figure 1 A cross-sectional view of a grinding stone of a workpiece processing device is shown.

[0042] Figure 3A It is a front view schematically showing an example of the workpiece processing method according to the first embodiment of the present invention in sequence.

[0043] Figure 3B It is a front view schematically showing an example of the workpiece processing method according to the first embodiment of the present invention in sequence.

[0044] Figure 3C It is a front view schematically showing an example of the workpiece processing method according to the first embodiment of the present invention in sequence.

[0045] Figure 3D It is a front view schematically showing an example of the workpiece processing method according to the first embodiment of the present invention in sequence.

[0046] Figure 4 It shows Figure 3B An enlarged view of the process shown.

[0047] Figure 5 is shown with Figure 4 An enlarged view of a process subsequent to the process shown.

[0048] Figure 6 is shown with Figure 5 An enlarged view of a process subsequent to the process shown.

[0049] Figure 7 This is a front view showing an example of a conventional workpiece processing method.

[0050] Figure 8A This is a front view showing an example of a workpiece processed in the first embodiment of the present invention.

[0051] Figure 8B This is a front view showing an example of a workpiece processed in the first embodiment of the present invention.

[0052] Figure 9A These are front views schematically showing another example of the workpiece processing method according to the first embodiment of the present invention in sequence.

[0053] Figure 9B These are front views schematically showing another example of the workpiece processing method according to the first embodiment of the present invention in sequence.

[0054] Figure 9CThese are front views schematically showing another example of the workpiece processing method according to the first embodiment of the present invention in sequence.

[0055] Figure 10A It is a cross-sectional view showing a modified example of the grindstone according to the first embodiment of the present invention.

[0056] Figure 10B is a schematic diagram showing the use of Figure 10A The front view of the grinding process of the grindstone is shown.

[0057] Figure 11A It is a cross-sectional view showing a grindstone of a workpiece processing apparatus according to a second embodiment of the present invention.

[0058] Figure 11B is a schematic diagram showing the use of Figure 11A The front view of the grinding process of the grindstone is shown.

[0059] Figure 11C is a schematic diagram showing the use of Figure 11A The front view of the grinding process of the grindstone is shown.

[0060] Figure 12 It is a front view schematically showing a workpiece processing apparatus according to a third embodiment of the present invention.

[0061] Figure 13 It is a front view showing a workpiece processing apparatus according to a fourth embodiment of the present invention. DETAILED DESCRIPTION

[0062] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 It is a front view schematically showing a workpiece processing apparatus 1 according to the first embodiment of the present invention. Figure 2 This is a cross-sectional view showing a grinding stone 5 of a workpiece processing apparatus 1. The workpiece processing apparatus 1 is used to grind a disk-shaped workpiece 2, such as a semiconductor wafer, glass substrate, or ceramic, and chamfer the outer periphery of the workpiece 2. The workpiece processing apparatus 1 is particularly suitable for chamfering high-hardness workpieces 2, such as silicon (Si), silicon carbide (SiC), gallium nitride (GaN), gallium arsenide (GaAs), and sapphire. However, the workpiece processing apparatus 1 can also be used to process other types of workpieces.

[0063] The workpiece processing device 1 includes a workpiece support mechanism 4 that supports a disk-shaped workpiece 2 and rotates it about a rotation axis 3, and a grindstone support mechanism 7 that supports a disk-shaped grindstone 5 and rotates it about a rotation axis 6. For example, the workpiece 2 is disk-shaped with a diameter of 50 to 300 mm and a thickness of approximately 1 mm or less, and the grindstone 5 is disk-shaped with a diameter of 100 to 200 mm and a thickness of approximately 20 to 60 mm. For convenience, the workpiece 2 is shown thicker in the drawings. The workpiece support mechanism 4 and the grindstone support mechanism 7 support the disk-shaped workpiece 2 and the disk-shaped grindstone 5 parallel to each other. The workpiece support mechanism 4 can rotate the disk-shaped workpiece 2 about a rotation axis 3 located at the center of the workpiece 2 in plan view and perpendicular to the workpiece 2. Similarly, the grindstone support mechanism 7 can rotate the disk-shaped grindstone 5 about a rotation axis 6 located at the center of the grindstone 5 in plan view and perpendicular to the grindstone 5. The rotation axis 3, which serves as the center of rotation of the workpiece 2 by the workpiece support mechanism 4, and the rotation axis 6, which serves as the center of rotation of the grindstone 5 by the grindstone support mechanism 7, are parallel to each other. The grindstone 5 and the workpiece 2 can be moved relative to each other, either toward or away from each other, by the grindstone support mechanism 7 or the workpiece support mechanism 4. For example, while the grindstone 5 is rotating, the grindstone support mechanism 7 can move the grindstone 5 in a direction both toward and away from the workpiece 2 within a plane parallel to the grindstone 5 and the workpiece 2 (a plane orthogonal to the rotation axis 3 and the rotation axis 6). Furthermore, the grindstone 5 can be moved in a plane orthogonal to the grindstone 5 and the workpiece 2 (a plane parallel to the rotation axis 3 and the rotation axis 6) in both directions toward and away from the workpiece 2. Therefore, the grindstone 5 can approach the workpiece 2 from any direction and be separated from the workpiece 2 in any direction, at least within a plane containing the rotation axes 3 and 6, by the grindstone support mechanism 7. The workpiece support mechanism 4 includes a temperature adjustment mechanism 15 for generating a flow of liquid or gas for maintaining a constant temperature of the rotating shaft 3 of the workpiece support mechanism 4. It should be noted that, although not described in detail, the workpiece support mechanism 4 and the grinding stone support mechanism 7 can be composed of a known adsorption table, a rotary motor, a movable table, and the like.

[0064] The grinding stone 5 of the workpiece processing device 1 is as follows Figure 2As shown, it has a base circular plate portion 5a serving as a base and a convex grinding portion 5b located on the outer periphery of the base circular plate portion 5a. The base circular plate portion 5a is made of an alloy such as aluminum or stainless steel, and is provided with a straight mounting hole 5c extending in the thickness direction for the rotation shaft 6 to pass through, and a recessed portion 5d for mounting to a retaining portion (such as a flange portion) not shown in the figure of the grindstone support mechanism 7. The convex grinding portion 5b located on the outer periphery of the grindstone 5 is made of a metal bond grindstone or a resin bond grindstone, etc., and its cross-sectional shape in the cross section through the rotation shaft 6 is convex toward the outside in the radial direction (the outer periphery), and has a shape having arc-shaped portions 5e at least at both ends in the thickness direction. In the case of Figure 2 In the example shown, the arcuate portions 5e at both ends in the thickness direction are connected by the same arcuate portion, and the convex ground portion 5b as a whole forms a semicircular shape. Furthermore, the convex ground portion 5b does not include a concave portion facing radially inward.

[0065] For use Figure 1 A workpiece processing method using the workpiece processing apparatus 1 shown will be described. Figures 3A to 3D 1 is a front view schematically showing an example of the workpiece processing method in sequence. Figures 3A to 3D In the figure, for ease of observation, the difference in size between the workpiece 2 and the grindstone 5 is not that large, but in reality, the grindstone 5 is much larger than the workpiece 2. First, the workpiece 2 (e.g., a semiconductor wafer) as a workpiece is mounted on the workpiece support mechanism 4, and the workpiece 2 is rotated around the rotation axis 3. The workpiece 2 rotates but does not move. The grindstone 5 mounted on the grindstone support mechanism 7 is rotated around the rotation axis 6 by the grindstone support mechanism 7, and is moved so that the outer periphery of the grindstone 5 abuts against the outer periphery of the workpiece 2. As an example, Figure 3A As shown in the figure, the grinding stone 5 mounted on the grinding stone support mechanism 7 is arranged relative to the workpiece 2 mounted on the workpiece support mechanism 4 so that the centers in the thickness direction are aligned. When the workpiece 2 is rotated around the rotation axis 3 and the grinding stone 5 is rotated around the rotation axis 6, as shown in the figure, Figure 3B As shown, the outer periphery of the grindstone 5 is brought into contact with the outer periphery of the workpiece 2 to perform grinding.

[0066] Thereafter, the grinding stone 5 is moved toward one surface side of the workpiece 2 (at Figures 3A to 3D In the example shown, the workpiece 2 is moved above the workpiece 2, and the rotation of the workpiece 2 and the rotation of the grinding stone 5 are continued, as shown in FIG. Figure 3CAs shown, with the outer periphery of the grindstone 5 in contact with the outer periphery of one surface of the workpiece 2, the grindstone 5 is moved relative to the workpiece 2. Specifically, the grindstone 5 is gradually moved from near the center in the thickness direction of the workpiece 2 and radially outward toward the radially inward side of one surface of the workpiece 2. As a result, the grindstone 5 grinds and chamfers the edge of one surface side (upper side) of the outer periphery of the workpiece 2, forming a chamfered portion 2a.

[0067] After the chamfering of the upper edge of the outer peripheral portion of the workpiece 2 is completed, the grinding stone 5 is moved from the inner side of the radial direction of the workpiece 2 to the outer side of the outermost end, and then the grinding stone 5 is moved to the other side of the workpiece 2 (at the Figures 3A to 3D In the example shown, the grinding stone 5 moves (descends) below the workpiece 2). At this time, the grinding stone 5 may descend while contacting the radially outermost end of the workpiece 2. Alternatively, the grinding stone 5 may move to a position outside the outermost end of the workpiece 2 and then descend without contacting the outermost end of the workpiece 2.

[0068] like Figure 3D As shown, while the outer periphery of the grinding stone 5 moved to a position lower than the center of the thickness direction of the workpiece 2 is in contact with the outer periphery of the other surface of the workpiece 2, the grinding stone 5 is moved from the outer periphery to the inner periphery of the radial direction of the workpiece 2 while continuing to descend. In this way, the outer periphery of the rotating grinding stone 5 is in contact with the outer periphery of the workpiece 2 to grind the workpiece 2, thereby chamfering the lower edge of the outer periphery of the workpiece 2 to form a chamfered portion 2a. Finally, the grinding stone 5 moves to a position lower than the lower surface of the workpiece 2, and the grinding stone 5 is no longer in contact with the workpiece 2, and the chamfering process of the workpiece 2 is completed. Figures 3A to 3DAs shown, the grinding stone 5 reciprocates (traverses) from a position opposite the center of the workpiece 2 toward one side and the other side (up and down) in the thickness direction of the workpiece 2 and the grinding stone 5, thereby chamfering the upper edge and the lower edge of the outer peripheral portion of the workpiece 2. Both the upper edge and the lower edge of the outer peripheral portion of the workpiece 2 are chamfered by the grinding stone 5 moving in the same direction in the radial direction of the workpiece 2 (from the radially outer side to the radially inner side of the workpiece 2). In this embodiment, the grinding stone 5 grinds only the straight portion of the front end of the workpiece 2 (the intermediate portion between the chamfered portions on both sides) while reciprocating. The chamfered portions 2a on both sides are formed solely by the grinding stone 5 moving in a single direction from the radially outer side to the radially inner side of the workpiece 2. For example, compared to the method described in Patent Document 5, which grinds not only the straight portion at the front end of the workpiece, but also the curved portion between the straight portion and the chamfered portion, and the chamfered portions on both sides, and the grinding stone and the workpiece move back and forth (traverse) relative to each other, in this embodiment, grinding can be easily and efficiently performed in a short time. Furthermore, the convex grinding portion 5b of the grinding stone 5 in this embodiment is mainly an arc-shaped curved surface, making it easy to calculate and design the curved surface shape to match the shape and size of the chamfered portion 2a to be formed. It should be noted that in some of the drawings, in order to facilitate the identification of the desired cross-sectional shape of the workpiece 2, the shape of the chamfered portion 2a in a substantially completed state is sometimes illustrated in the middle of or before the formation of the chamfered portion 2a.

[0069] Reference Figures 4-6 This workpiece machining method will be described in more detail. In the machining method of this embodiment, the movement conditions for the relative movement of the grindstone 5 and the workpiece 2 are calculated so that the contact portion between the convex grinding portion 5b of the grindstone 5 and the workpiece 2 moves along the desired cross-sectional shape of the workpiece 2. Since the dimensions of the grindstone 5 in this embodiment are known, the movement conditions for relative movement between the grindstone 5 and the workpiece 2 are calculated based on the radius of curvature of the arcuate portions 5e of the grindstone 5 located at both ends of the convex grinding portion 5b in the thickness direction. Based on the calculated movement conditions, the grindstone support mechanism 7 or the workpiece support mechanism 4 moves the grindstone 5 relative to the workpiece 2. For example, the desired cross-sectional shape of the workpiece 2 is represented as two-dimensional coordinates within a plane containing the rotation axis 3 of the workpiece 2 and the rotation axis 6 of the grindstone 5. The relative movement conditions between the grindstone 5 and the workpiece 2 are set so that the contact portion between the grindstone 5 and the workpiece 2 passes through a point at each coordinate. Thus, in this embodiment, the grindstone 5 and the workpiece 2 are relatively moved by NC control (numerical control), thereby grinding the workpiece 2.

[0070] Specifically, if Figure 4As shown, the grinding stone 5 is brought into contact with the outer peripheral end surface of the workpiece 2 to grind and reduce the diameter of the workpiece 2. The grinding stone 5 is much larger than the workpiece 2, so the portion of the convex grinding portion 5b of the grinding stone 5 that contacts the outer peripheral end surface of the workpiece is substantially linear. Therefore, the outer peripheral portion of the workpiece 2 is ground in a substantially linear manner, reducing the diameter of the workpiece 2. When the convex grinding portion 5b of the grinding stone 5 is brought into contact with the outer peripheral end surface of the workpiece 2 in the thickness direction ( Figure 4 In a state where the center of the grinding stone 5 (in the vertical direction) is aligned with the center of the thickness direction of the workpiece 2, the workpiece 2 is ground until the diameter of the workpiece 2 reaches the desired size. Thereafter, the grinding stone 5 is moved relative to the workpiece 2 in the thickness direction to grind the workpiece 2 in such a manner as to form a straight portion of the desired cross-sectional shape of the workpiece 2 (indicated by a two-dot chain line). In this way, the grinding stone 5 is relatively moved in the thickness direction of the workpiece 2 to form a straight portion of the desired cross-sectional shape of the workpiece 2. After the grinding stone 5 reaches a predetermined position P1 on one side (for example, the upper side), as shown in FIG. Figure 5 As shown, while the relative movement toward one side of the surface is continued, the workpiece 2 is moved relative to the workpiece 2 in a curved manner from the outside to the inside in the radial direction. By appropriately moving the grinding stone 5 relative to the workpiece 2 in the thickness direction and the radial direction based on the pre-calculated movement conditions, the grinding stone 5 passes through the desired curved trajectory relative to the workpiece 2. Moreover, after reaching the position P2 where the angle α relative to the starting point P1 of the relative movement from the outside to the inside in the radial direction of the workpiece 2 becomes a predetermined angle set in advance, the relative movement amount of the grinding stone 5 and the workpiece 2 is set to be constant, and the grinding stone 5 is moved relative to the workpiece 2 in a straight line. The angle α is an angle measured from the inner circumference of the workpiece 2 within the plane containing the rotating axis 3 of the workpiece 2 and the rotating axis 6 of the grinding stone 5. Furthermore, the grinding stone 5 moves relative to the outside of the surface of one side in the thickness direction of the workpiece 2 without contacting the workpiece 2, completing the grinding of one side of the workpiece 2. On the other side of the surface of the workpiece 2, as Figure 6 As shown, by making Figure 5 The operation on one surface side of the workpiece 2 shown is substantially an operation reversed vertically, and the other surface of the workpiece 2 is ground.

[0071] The difference in size between the grinding stone 5 and the workpiece 2 is actually much larger than Figures 4-6 As shown in FIG. 5 , the arc-shaped portion 5e of the grinding stone 5 may have a curvature radius several tens of times greater than the thickness of the workpiece 2. In some cases, the portion of the arc-shaped portion 5e of the grinding stone 5 that contacts the outer peripheral surface of the workpiece 2 may be substantially straight. For example, at the time point when the grinding stone 5 moves and the movement angle α becomes a predetermined value (see FIG. Figure 5 、 6 ), the arc-shaped portion 5e of the grinding stone 5 is in the desired shape (in Figure 5 、 6The gap generated between the grinding stone 5 and the workpiece 2 (shown by the double-dashed line) is very small and can be ignored, and there is a possibility that the grinding stone 5 contacts the workpiece 2 in a manner that can grind the chamfered portion 2a of the workpiece 2 as a whole into the desired shape. In this case, it is also considered to stop the movement of the grinding stone 5 at the time when the grinding stone 5 moves and the movement angle α becomes a predetermined size, and to omit the process of moving the grinding stone 5 linearly relative to the workpiece 2. In the case of more precise grinding, it is preferable to move the grinding stone 5 in a curved line until the movement angle α becomes a predetermined size, and then move the grinding stone 5 linearly relative to the workpiece 2. However, in the case of relatively rough grinding as a previous stage of precise grinding, it is also possible to omit the process of moving the grinding stone 5 linearly relative to the workpiece 2 after moving the grinding stone 5 in a curved line until the movement angle α becomes a predetermined size, thereby simplifying the operation.

[0072] Thus, in this embodiment, by relatively moving the grindstone 5 and workpiece 2 according to precalculated movement conditions, the contact portion of the grindstone 5 and workpiece 2 follows a movement trajectory calculated based on the desired cross-sectional shape of the workpiece 2. As a result, the workpiece 2 can be formed into the desired cross-sectional shape. Furthermore, when machining a different type of workpiece 2, the movement conditions for machining the newly machined workpiece 2 are calculated to match the desired cross-sectional shape of the workpiece 2 being machined. In this case, since the movement conditions are calculated based on the curvature radius of the arc-shaped portion 5e of the grindstone 5, workpieces 2 of various shapes can be accurately machined using the same grindstone 5.

[0073] The effects of this embodiment are described. Figure 7 As shown, in conventional machining methods using a grindstone 16 having a formed groove 16a, there is a high likelihood of wear and damage occurring at specific locations on the grindstone 16, such as the portion P3 of the inner circumference of the formed groove 16a where the workpiece 2 initially contacts. When machining multiple workpieces 2, wear and damage to this portion P3 can cause the shape of the formed groove 16a to change, resulting in reduced machining accuracy when machining the workpieces 2 using this grindstone 16. In this case, the grindstone 16 needs to be replaced or reshaped. In contrast, in this embodiment, the convex grinding portion 5b of the grindstone 5 contacts the workpiece 2 at various locations during grinding, so wear and damage are not particularly prevalent in specific locations. Consequently, the life of the grindstone 5 is relatively long.

[0074] In the conventional processing method described in Patent Document 6, it is structurally difficult to use a grinding stone that is too large (large diameter), so a small (small diameter) grinding stone must be used for processing. As a result, the life of the grinding stone is short, and the grinding stone needs to be replaced and shaped more frequently. However, in this embodiment, the grinding stone 5 and the grinding stone support mechanism 7 are less likely to interfere with other components, specifically the workpiece support mechanism 4, so the structural constraints are smaller, and a large (large diameter) grinding stone 5 can be used to process the workpiece 2. Therefore, the life of the grinding stone 5 is long, and the frequency of replacing and shaping the grinding stone 5 is low. In addition, in the processing method described in Patent Document 6, the rotation direction of the grinding stone is substantially consistent with the relative movement direction relative to the workpiece (both are in the thickness direction of the workpiece 2). Therefore, when there are large uneven portions on the outer periphery of the grinding stone, linear marks along the rotation direction (the thickness direction of the workpiece) are easily generated on the outer periphery of the workpiece due to the rotation of the grinding stone. As the grindstone rotates, it moves relative to the workpiece in the same direction as the rotation direction, that is, in a direction substantially parallel to the linear marks. Therefore, the linear marks are not eliminated and tend to remain. The portion of the grindstone that creates the linear marks on the outer circumference of the workpiece (the large concave and convex portion) moves relative to the workpiece in the thickness direction while maintaining its position in the circumferential direction of the workpiece. Therefore, there is a possibility that a portion of the workpiece will remain that has not come into contact with the large concave and convex portion and has not been ground to the same depth as the linear marks. As a result, even if the grindstone moves, the linear marks are not eliminated and tend to remain. It should be noted that the workpiece rotates in a direction perpendicular to the rotation direction of the grindstone, but the length of the circumferential movement of the workpiece due to the rotation is much longer than the length of the relative movement of the grindstone and the workpiece in the thickness direction of the workpiece. The grindstone grinds the entire circumference of the workpiece and moves relative to it in the thickness direction of the workpiece. Therefore, in order to minimize the processing time of the workpiece, the speed at which the grindstone moves relative to the workpiece in the thickness direction must be kept moderate. The circumferential width of the workpiece in contact with the grinding stone is narrow. To ensure that the speed at which the grinding stone moves relative to the workpiece in the thickness direction is not slow, the workpiece's rotational speed (circumferential movement speed) is increased to shorten the time required for the grinding stone to contact the workpiece throughout its entire circumference for grinding. This increased rotational speed results in a rougher surface finish after grinding, even when the workpiece and grinding stone rotate in mutually orthogonal directions. In contrast, in this embodiment, the rotational direction of the grinding stone 5 is substantially orthogonal to the direction of relative movement relative to the workpiece 2. The rotational direction of the grinding stone 5 is circumferential, and the relative movement direction is thickness-wise. If the outer circumference of the grinding stone 5 has large irregularities, the rotation of the grinding stone 5 will produce linear scratches along the outer circumferential surface of the workpiece 2. Since the grinding stone 5 moves relative to the workpiece 2 in a direction orthogonal to the rotational direction, i.e., in a direction substantially orthogonal to the linear scratches, the linear scratches are less likely to remain.The portion of the grinding stone 5 that creates the linear marks on the outer peripheral surface of the workpiece 2 (the large concave and convex portion) moves in a direction orthogonal to the linear marks while rotating circumferentially. Therefore, the large concave and convex portion sequentially contacts the substantially entire outer peripheral surface of the workpiece 2. Consequently, the substantially entire outer peripheral surface of the workpiece 2 is ground to the same depth by the large concave and convex portion as by the linear marks. Thus, since the rotation direction of the grinding stone 5 is substantially orthogonal to the direction of relative movement relative to the workpiece 2, the linear marks created on the outer peripheral surface of the workpiece 2 are easily eliminated, resulting in a smooth surface. It should be noted that in this structure, even if the workpiece 2 rotates at a high speed, because the rotation direction of the grinding stone 5 (the circumferential direction of the workpiece 2) and the relative movement direction of the grinding stone 5 (the thickness direction of the workpiece 2) are orthogonal and the relative movement distance is short, even if the grinding stone 5 moves relatively slowly in the thickness direction of the workpiece 2, the processing time does not increase significantly. Therefore, the relative moving speed of the grindstone 5 in the thickness direction of the workpiece 2 is made relatively slow, and the entire circumference of the workpiece 2 is fully ground, so that the surface roughness of the ground workpiece can be improved.

[0075] In the conventional machining method described in Patent Document 5, grinding is performed by relatively moving the workpiece along the outer shape of the grinding stone. Therefore, the shape of the finished workpiece is determined by the outer shape of the grinding stone (particularly the shape and angle of the curved or linear inclined surface of the grinding stone). Therefore, in order to form workpieces of different shapes, it is necessary to replace the grinding stone. In contrast, in the present embodiment, the relative movement of the grinding stone 5 and the workpiece 2 is not performed along the outer shape of the grinding stone 5, but is performed according to a movement condition calculated based on the curvature radius of the arc-shaped portion 5e of the convex grinding portion 5b of the grinding stone 5. Therefore, when forming workpieces 2 of different shapes, there is no need to replace the grinding stone 5; simply changing the movement condition is sufficient. In other words, without replacing the grinding stone 5, the same grinding stone 5 can be used to form workpieces 2 of various shapes. The movement condition is calculated based on the curvature radius of the arc-shaped portion 5e of the convex grinding portion 5b of the grinding stone 5, and the relative movement of the grinding stone 5 and the workpiece 2 is numerically controlled based on this movement condition, resulting in good machining accuracy. As described above, according to the present embodiment, various excellent effects can be achieved, such as being able to form workpieces 2 of various shapes using the same grindstone 5 , achieving good machining accuracy, and extending the life of the grindstone 5 .

[0076] According to the processing device and processing method of this embodiment, Figure 8A As shown in FIG, the outer periphery is formed by a pair of arc-shaped parts and a straight line part connecting them to form a so-called T-shaped workpiece 2 and as shown in FIG. Figure 8B As shown, the workpiece 2 having a so-called rounded shape with a semicircular outer periphery can be formed with good precision. Figure 8AIn the case of the T-shaped workpiece 2 shown in FIG. 1 , machining is performed under the following movement conditions: the movement conditions are based on the curvature radii R1 and R2 of the pair of arc-shaped portions of the outer periphery, the lengths X1 and X2 of the inclined surface portions of the straight line connecting the respective arc-shaped portions, the angles θ1 and θ2 of the inclined surface portions with respect to the surface of the workpiece 2, the length X3 of the straight line portion between the pair of arc-shaped portions, and the curvature of the pair of arc-shaped portions. Figure 8A The curvature radius of the arc-shaped portion 5e of the convex grinding portion 5b of the grindstone 5 (not shown) is calculated and obtained. Figure 8B In the case of the workpiece 2 having a rounded corner as shown, the machining is performed under the following movement conditions, which are based on the radius R of the semicircular portion of the outer periphery, the lengths X1 and X2 of the inclined surface portions of the straight lines connecting the semicircular portion to both sides, the angles θ1 and θ2 of these inclined surface portions with respect to the surface of the workpiece 2, and the lengths X2 and X3 of the inclined surface portions of the semicircular portion. Figure 8B The curvature radius of the arc-shaped portion 5e of the convex grinding portion 5b of the grindstone 5 (not shown) is calculated and obtained. Figure 8A The T-shaped workpiece 2 shown and Figure 8B The workpiece 2 with rounded corners shown can be machined with good precision by numerical control according to the following movement conditions, which are obtained by calculation based on the dimensions of each part of the desired cross-sectional shape shown in the figure and the curvature radius of the arc-shaped portion 5e of the convex grinding portion 5b of the grinding stone 5. Figure 8B In the case of the rounded workpiece 2 shown, there is no straight portion at the outer peripheral end. Therefore, after the workpiece 2 is ground until the diameter of the workpiece 2 reaches the desired size, there is no need to form a straight portion in the workpiece 2 while relatively moving the grindstone 5 in the thickness direction.

[0077] Next, use Figure 1 Another example of a workpiece processing method using the workpiece processing apparatus 1 shown will be described. Figures 9A to 9C 1 is a front view schematically showing an example of the workpiece processing method in sequence. In this example, the grinding stone 5 mounted on the grinding stone support mechanism 7 is mounted on the radial inner side of the workpiece 2 mounted on the workpiece support mechanism 4 from one side of the workpiece 2 in the thickness direction (at Figures 9A to 9C In the example shown, the outer periphery of the grinding stone 5 is brought into contact with the outer periphery of the workpiece 2, and grinding of the edge of the outer periphery of the workpiece 2 is started. Then, while the rotation of the workpiece 2 and the rotation of the grinding stone 5 are continued, the grinding stone support mechanism 7 moves the grinding stone 5. Specifically, as Figure 9A As shown in FIG, the grinding stone 5 is directed toward the other side of the thickness direction of the workpiece 2 ( Figures 9A to 9CIn the example shown, it is below the workpiece 2) and moves from the inner side to the outer side of the radial direction of the workpiece 2. By this movement, the upper edge of the outer peripheral portion of the workpiece 2 is chamfered to form a chamfered portion 2a. Figure 9B As shown, after the grinding stone 5 reaches the radially outermost end of the workpiece 2, the grinding stone 5 is further lowered and moved to a position below the center in the thickness direction of the workpiece 2. At this time, the grinding stone 5 is brought into contact with the radially outermost end of the workpiece 2 and is lowered while grinding the workpiece 2.

[0078] like Figure 9C As shown, the grinding stone 5 is moved to a position below the center of the thickness direction of the workpiece 2 and is moved from the outside to the inside in the radial direction of the workpiece 2 while continuing to descend. At this time, the outer periphery of the rotating grinding stone 5 is brought into contact with the outer periphery of the workpiece 2 to grind the workpiece 2, chamfering the lower edge of the outer periphery of the workpiece 2 to form the chamfered portion 2a. Finally, the grinding stone 5 is moved to a position below the lower surface of the workpiece 2, and the grinding stone 5 is no longer in contact with the workpiece 2, and the chamfering process of the workpiece 2 is completed. Figures 9A to 9C As shown, by simply moving the grinding stone 5 from the radially inner side to the outer side of the workpiece 2, slightly lowering it, and then moving it from the radially outer side to the inner side of the workpiece 2, both surfaces of the workpiece 2 can be chamfered. However, when chamfering the upper edge of the outer peripheral portion of the workpiece 2, the grinding stone 5 can also be rotated while contacting the workpiece 2 and moving from the radially outer side to the inner side of the workpiece 2. In this case, both the upper and lower edges of the outer peripheral portion of the workpiece 2 are chamfered by moving the grinding stone 5 in the same direction (from the radially outer side to the inner side).

[0079] exist Figures 3A to 6 The examples shown and Figures 9A to 9CIn all the examples shown, the grindstone support mechanism 7 adjusts the size of the chamfered portion 2a by adjusting the position of the grindstone 5 in the radial direction of the workpiece 2 before chamfering begins, i.e., the position at which the grindstone 5 begins contact with the workpiece 2, and the position of the grindstone 5 at the end of chamfering, i.e., the position at which the grindstone 5 ends contact with the workpiece 2. Furthermore, taking into account the adjusted size of the chamfered portion 2a and the speed at which the grindstone 5 grinds the workpiece 2, the grindstone support mechanism 7 adjusts the angle, shape, and other aspects of the chamfered portion 2a of the workpiece 2 by adjusting the speed at which the grindstone 5 descends and the speed at which it moves in the radial direction of the workpiece 2. Furthermore, by varying the contact angle of the grindstone 5 with the workpiece 2 depending on which portion of the curved portion of the outer periphery of the grindstone 5 is ground, the angle, shape, and other aspects of the chamfered portion 2a of the workpiece 2 can be adjusted. Thus, the desired shape and size of the chamfered portion 2a of the workpiece 2 can be achieved primarily by controlling the movement of the grindstone 5 through the grindstone support mechanism 7. To this end, the grindstone support mechanism 7 preferably drives the grindstone 5 through numerical control (NC control).

[0080] The aforementioned configuration is one in which the grindstone support mechanism 7 simultaneously rotates and moves the grindstone 5, while the workpiece support mechanism 4 rotates but does not move the workpiece 2. However, this configuration is not limited to such a configuration. Specifically, a configuration in which the grindstone support mechanism 7 merely rotates the grindstone 5 without moving it, and the workpiece support mechanism 4 rotates the workpiece 2 and moves it through numerical control, is also possible. In this case, the workpiece support mechanism 4 can move the workpiece 2 both in the direction of approaching the grindstone 5 and in the direction of separation from the grindstone 5 within a plane parallel to the grindstone 5 and the workpiece 2 (a plane orthogonal to the rotation axes 3 and 6). Furthermore, the workpiece 2 can also be moved both in the direction of approaching the grindstone 5 and in the direction of separation from the grindstone 5 within a plane orthogonal to the grindstone 5 and the workpiece 2 (a plane parallel to the rotation axes 3 and 6). Therefore, the grindstone support mechanism 7 allows the workpiece 2 to approach the grindstone 5 from any direction and to separate from the grindstone 5 in any direction, at least within a plane including the rotation axes 3 and 6. In this structure, the workpiece 2 and the grinding stone 5 can also be aligned. Figures 3A to 6 or Figures 9A to 9C The same positional relationship as shown in each step can be achieved by relatively moving the workpiece 2 and the grinding stone 5. Figures 3A to 6 or Figures 9A to 9C The same processing method as shown.

[0081] In this embodiment, the grindstone 5 and the workpiece 2 rotate in the same or opposite directions, rather than in mutually orthogonal directions. This creates a synergistic effect between the rotation of the grindstone 5 and the rotation of the workpiece 2, eliminating the need for the grindstone 5 to rotate at a high speed. Consequently, the grindstone support mechanism 7 need not be one capable of high-speed rotation, simplifying the structure and reducing costs. Furthermore, since grinding is performed while the workpiece 2 and the grindstone 5 rotate parallel to each other, the surface roughness of the chamfered portion of the workpiece 2 can be reduced.

[0082] According to this embodiment, the grindstone 5 is arranged parallel to the workpiece 2. This allows the grindstone 5 to be larger without interfering with the workpiece support mechanism 4. This allows the outer periphery of the workpiece 2 to be formed into any desired cross-sectional shape using a large grindstone 5, without complicating the structure of the processing device 1 including the grindstone support mechanism 7. Furthermore, the use of a large grindstone 5 improves processing efficiency, shortening processing time, and allows a wider range of the outer periphery of the grindstone 5 to be utilized for processing, thereby extending the life of the grindstone 5. Furthermore, when processing using a grindstone having a groove (forming groove) formed in a shape corresponding to the shape of the finished workpiece 2, the inner periphery of the groove (particularly the inclined surface) that contacts the edge of the workpiece before chamfering is prone to wear and damage. However, in this embodiment, the grindstone 5 is not continuously contacted by a specific portion of the grindstone 5, so damage to the grindstone 5 is less likely to occur, extending its life.

[0083] When machining a workpiece by inserting it into a shaping groove provided in a grinding stone, a chamfered portion of a specific shape and size can be formed. However, to form a chamfered portion of a different shape and size, a grinding stone with a different groove must be replaced. However, according to this embodiment, the grinding stone 5 having a convex grinding portion 5b is moved relative to the workpiece 2 to perform chamfering. By using numerical control to change the movement path of the grinding stone 5, the shape and size of the resulting chamfered portion 2a can be varied. In other words, a single grinding stone 5 can be used to form chamfered portions 2a of various shapes and sizes.

[0084] In addition, when inserting the workpiece into the groove provided in the grinding stone for processing, it is not easy to supply grinding water (coolant) to the processing part because the processing is carried out in a closed narrow space. However, in this embodiment, the convex portion of the outer periphery of the grinding stone 5 abuts against the workpiece 2, and processing is carried out in an open space, so that grinding water can be easily and reliably supplied to the processing part. As a result, it is possible to grind smoothly without causing clogging of the holes, excessive friction, or heat. In particular, low-angle chamfering (for example, chamfering with an angle of less than 11 degrees), which is difficult when inserting the workpiece into the groove provided in the grinding stone for processing, can be easily and accurately achieved. Moreover, it is possible to continuously chamfer the edges of the arc-shaped portion of the outer periphery of the workpiece 2 and the edges of the oriented plane portion using a large grinding stone 5 without the need to provide multiple grooves. Therefore, the grinding stone 5 can be made into a simple structure, and the chamfered portion 2a, the notch portion, and the oriented plane portion can be formed through a series of processes, so the processing time is short and the processing cost can be reduced.

[0085] exist Figures 10A-10B A modified example of the grinding stone of this embodiment is shown in FIG. Figure 10A As shown, for example, there is a base circular plate portion 8a made of metal and a convex grinding portion 8b composed of a resin bond grindstone located on the outer periphery thereof, and a straight mounting hole 8c and a recessed portion 8d extending in the thickness direction and for the rotating shaft 6 to pass through are provided on the base circular plate portion 8a. The convex grinding portion 8b is convex toward the outside in the radial direction, and has a curved portion in at least a portion in the cross section along the rotating shaft, and no concave portion toward the inside in the radial direction is provided. The convex grinding portion 8b of the grindstone 8 of this embodiment has a flat portion, i.e., a straight portion 8f in the cross section passing through the rotating shaft 6, in a portion of the outer periphery, particularly in the middle portion in the thickness direction (the position between a pair of arc-shaped portions 8e at the two ends in the thickness direction). In Figure 10A In FIG. 8 , the boundary between the arc-shaped portion 8e and the straight portion 8f is represented by an imaginary line (two-dot chain line). The straight portion 8f of the convex grinding portion 8b is as shown in FIG. Figure 10B As shown, this grinding stone 8 is primarily used to reduce the diameter of a workpiece 2 by grinding the middle portion of the outer periphery of the workpiece 2 in the thickness direction, that is, the portion between the chamfered portions 2a at the edges of the workpiece 2 in the thickness direction. This grinding stone 8 efficiently and accurately grinds the middle portion of the outer periphery of the workpiece 2 in the thickness direction, reducing surface roughness. Alternatively, the straight portion 8f may be a portion with a coarser grinding stone grit, while the arc-shaped portion 8e may be a portion with a finer grinding stone grit, allowing for more precise grinding than that achieved by the straight portion 8f.

[0086] Although not shown, flanges are provided in the mounting hole 8c and recess 8d of the base disc portion 8a. The spindle constituting the rotating shaft 6 is inserted into the flange in the mounting hole 8c, and a fixing member such as a nut is attached to the distal end of the spindle protruding into the recess 8d. Thus, the grindstone 8 is fixed to the spindle constituting the rotating shaft 6 and can rotate together with the spindle.

[0087] Next, a second embodiment of the present invention will be described. Figure 11A : is a cross-sectional view of a grinding stone 9 of a workpiece processing device according to the present embodiment. In the present embodiment, a two-stage grinding process is performed: grinding for reducing the radius of the workpiece 2 and grinding the chamfers of both sides of the outer periphery of the workpiece 2 in order to form the workpiece 2 into the desired cross-sectional shape. Generally, the former grinding is rough grinding, and the latter grinding is precision grinding. Precision grinding and rough grinding are relative expressions. Compared with rough grinding, precision grinding is grinding with better shape and size accuracy and smaller surface roughness of the ground surface. In the grinding stone 9 of the present embodiment, a convex grinding portion (precision grinding portion) 9b mainly used for grinding to form the workpiece 2 into the desired cross-sectional shape and a grinding portion (rough grinding portion) 9f with a rectangular cross-section mainly used for grinding to reduce the radius of the workpiece 2 are provided on the outer periphery of the base circular plate portion 9a. The convex grinding portion 9b is the same structure as the convex grinding portions 5b and 8b of the grinding stones 5 and 8 of the first embodiment, and has arc-shaped portions 9e at both ends in the thickness direction. The grinding portion 9f of the grinding stone 9 of this embodiment is rectangular in cross section. Figures 11A to 11C As shown, it has a rectangular shape in a cross section along the rotation axis 6. That is, the surface of the grinding portion 9f having a rectangular cross section facing the workpiece 2 is a straight line parallel to the thickness direction of the grindstone 9 in a cross section along the rotation axis 6.

[0088] In this embodiment, the unprocessed workpiece 2 is mounted on the workpiece support mechanism 4 and the workpiece 2 is rotated, and the grinding stone 9 mounted on the grinding stone support mechanism 7 is rotated around the rotation axis 6 as the center. Figure 11B As shown in FIG. 1 , the rectangular cross-sectional grinding portion 9f is brought into contact with the outer periphery of the workpiece 2. Thus, the outer periphery of the workpiece 2 is roughly ground so that the outer diameter of the workpiece 2 becomes the desired size and the middle portion of the thickness direction of the outer periphery is mainly smoothed. Figure 11C As shown, the convex grinding portion 9b of the grindstone 9 is used to grind the Figures 3A to 6 or Figures 9A to 9CThe processing method of the first embodiment shown is substantially the same method, and the chamfering of the edges of the two sides of the workpiece 2 is performed so that the workpiece 2 is formed into the desired cross-sectional shape. In this embodiment, the convex grinding portion 9b of the grinding stone 9 is used to perform grinding (precision grinding) that is more precise than the grinding for reducing the radius of the workpiece 2. In this embodiment, the same effect as the first embodiment is obtained, and it is possible to easily perform two steps using only a single grinding stone 9 when the chamfering portion is performed through a two-stage grinding process, and the manufacturing process is simple and low-cost. However, it is also possible that for grinding to reduce the radius of the workpiece 2, not only the cross-sectional rectangular grinding portion 9f is used, but also the convex grinding portion 9b is used. Similarly, for grinding to chamfer the edges of the two sides of the workpiece 2 so that the workpiece 2 is formed into the desired cross-sectional shape, not only the convex grinding portion 9b is used, but also the cross-sectional rectangular grinding portion 9f is used. For example, the cross-sectional rectangular grinding portion 9f is a portion having a coarse grinding stone, and the convex grinding portion 9b is a portion having a finer grinding stone than the cross-sectional rectangular grinding portion 9f and used for precision grinding.

[0089] Typically, when chamfering a workpiece 2, such as a semiconductor wafer, the outer surface of the workpiece 2 is ground with a grinding stone to reduce the radius. Unnecessary portions of the workpiece 2 are removed while the outer shape is adjusted to the desired size and centering is performed. Subsequently, a grinding stone is used to form a chamfered portion 2a on the workpiece 2. When these grinding operations are performed using a convex grinding portion, the first stage of grinding (rough grinding) to reduce the radius of the workpiece 2 is primarily performed by bringing the center of the convex grinding portion of the grinding stone in the thickness direction into contact with the workpiece. The second stage of grinding (precision grinding) to form the chamfered portion 2a is performed by bringing the arc-shaped portions at both ends of the convex grinding portion in the thickness direction into contact with the workpiece. Typically, the grinding operation to reduce the radius of the workpiece 2 results in a greater amount of grinding (volume of grinding) than the grinding operation to form the chamfered portion 2a. Consequently, the portion near the center of the convex grinding portion in the thickness direction is more severely worn than the arc-shaped portions at both ends in the thickness direction, disrupting the overall shape of the convex grinding portion. As a result, the machining accuracy of the workpiece 2 may be reduced. In contrast, in this embodiment, the grinding for reducing the radius of the workpiece 2 is mainly performed using the rectangular cross-sectional grinding portion 9f, while the grinding for forming the chamfered portion 2a can be performed using the convex grinding portion 9b. In other words, the grinding for reducing the radius of the workpiece 2 and the grinding for forming the chamfered portion 2a can be performed using other parts of the grindstone 9. The shape and size of the rectangular cross-sectional grinding portion 9f and the shape and size of the convex grinding portion 9b can be managed independently. Even if the wear amounts of each are different, good machining can be achieved by appropriately adjusting the machining conditions. Furthermore, the convex grinding portion 9b is only used for grinding, which is mainly used to form the chamfered portion 2a. There is no situation where only one part (the part near the center in the thickness direction) wears significantly more than the other parts, but rather wears relatively evenly. Therefore, the shape of the convex grinding portion 9b of the grindstone does not change that much, which can suppress the reduction in the machining accuracy of the workpiece 2. The ground portion 9f with a rectangular cross section wears significantly, but the surface facing the workpiece 2 is a simple straight line parallel to the thickness direction of the grindstone 9 , so even if wear occurs, the machining accuracy does not decrease significantly.

[0090] It should be noted that the mounting hole 9c of the grindstone 9 in this embodiment is tapered. Although not shown, this structure does not utilize a flange. Instead, the tapered portion of the spindle forming the rotating shaft 6 is inserted into the tapered mounting hole 9c. A fixing member, such as a nut, is attached to the distal end of the spindle protruding into the recess 9d. This allows the grindstone 9 to be secured to the spindle forming the rotating shaft 6 and supported for rotation therewith. In other words, the grindstone 9 in this embodiment does not require a flange, yet can be stably secured to the spindle forming the rotating shaft 6 while preventing the grindstone 9 from becoming eccentric relative to the rotating shaft 6 (spindle).

[0091] Next, a third embodiment of the present invention will be described. Figure 12 This is a front view schematically illustrating a workpiece processing device according to this embodiment. The workpiece processing device according to this embodiment includes a grinding stone 9, similar to the second embodiment, and a circular grooved grinding stone 12, arranged obliquely relative to the tangent direction of the outer periphery of a circular workpiece 2. The grooved grinding stone 12 is supported by a grooved grinding stone support mechanism 13 and is rotatable about a rotation axis 14. This workpiece processing device performs chamfering through a two-stage grinding process. The aforementioned machining method is implemented using the grinding stone 9, similar to the second embodiment, with its rectangular cross-sectional grinding portion 9f and convex grinding portion 9b, to perform the rough grinding process in the first stage. Furthermore, the grooved grinding stone 12, arranged obliquely relative to the tangent direction of the outer periphery of the workpiece 2, performs the precision grinding process in the second stage. A concave groove 12a is provided on the outer periphery of the grooved grinding stone 12. The outer periphery of the workpiece 2 is inserted into this groove 12a, so that the inner circumferential surface of the groove 12a contacts the outer periphery of the workpiece 2, thereby grinding and forming the chamfered portion. According to this embodiment, the effects of the spiral processing method such as reduced surface roughness are achieved, and by performing rough grinding using the grindstone 9 that moves while rotating, the subsequent spiral precision grinding using the grooved grindstone 12 can be performed more efficiently in a shorter time.

[0092] The workpiece processing apparatus of this embodiment includes a dressing grindstone 11 for dressing a grooved grindstone 12 that can be mounted on the workpiece support mechanism 4 in place of the workpiece 2 and is rotatable about the rotation axis 3. The dressing grindstone 11 is constructed, for example, from a GC grindstone, which is harder than the grooved grindstone 12, which is a resin-bonded grindstone, and has a diameter and thickness approximately equal to that of the workpiece 2. The dressing grindstone 11, which is constructed from a GC grindstone or the like, is typically machined using a grindstone 9, which is a metal-bonded grindstone, in the same manner as used for machining the workpiece 2, to obtain a cross-sectional shape (a shape corresponding to the predetermined shape of the grooves 12a) intended to be transferred to the inclined grooved grindstone 12. The same method used for machining the workpiece 2 involves calculating movement conditions for the contact portion between the convex grinding portion 9b of the grinding stone 9 and the dressing grindstone 11, based on the radius of curvature of the arcuate portion 9e of the grinding stone 9, along a shape corresponding to the predetermined groove 12a. The dressing grindstone 11 is then moved relative to the grinding stone 9 according to these movement conditions, thereby forming the outer shape of the dressing grindstone 11. The predetermined groove 12a is configured to form the workpiece 2, which contacts the inner circumference of the groove 12a, into the desired cross-sectional shape. The dressing grindstone 11, thus formed in the cross-sectional shape, is rotated about the rotation axis 3 while being pressed against the outer circumference of the inclined grooved grindstone 12 before the grooves are formed or shaped. The outer shape of the dressing grindstone 11 is transferred to the outer circumference of the grooved grindstone 12, thereby forming or shaped the grooves 12a. This facilitates the dressing of the grooved grindstone 12. Note that the dressing grindstone 11 is formed into a shape that includes the expected change in cross-sectional shape based on empirical prediction of a slight change in cross-sectional shape that occurs during dressing of the inclined grooved grindstone 12 .

[0093] It should be noted that regarding the wear strength of grindstones, for example, a GC grindstone with a grit size of #320 is stronger than a resin-bonded grindstone with a grit size of #3000, and a metal-bonded grindstone with a grit size of #800 is stronger than a GC grindstone with a grit size of #320. Therefore, a GC grindstone with a grit size of #800 can be ground into a desired cross-sectional shape using a metal-bonded grindstone with a grit size of #320. Furthermore, by pressing a GC grindstone with a grit size of #320 against the inner circumference of a groove formed in a resin-bonded grindstone with a grit size of #3000, the groove shape can be reshaped. It should be noted that the grindstones described below generally have the aforementioned grit sizes. In a conventional workpiece processing device that uses a grindstone with formed grooves, made of a metal-bond grindstone, for rough grinding and an inclined grooved grindstone, made of a resin-bond grindstone, for precision grinding, a dressing grindstone, made of a GC grindstone, is brought into contact with the inner circumference of the formed grooves of the metal-bond grindstone to transfer the shape of the formed grooves. The dressing grindstone, made of the GC grindstone, is then brought into contact with the inclined resin-bond grindstone to form or shape the grooves. The grooves formed in the inclined grooved grindstone, made of the resin-bond grindstone, are then used to precisely grind the workpiece (wafer). Consequently, the workpiece can only be formed into a cross-sectional shape that depends on the shape of the formed grooves of the metal-bond grindstone, and cannot be formed into different cross-sectional shapes.

[0094] In contrast, in the present invention, the dressing grindstone 11, which is a GC grindstone, can be formed into any cross-sectional shape using the convex grinding portion 9b of the grindstone 9, which is a metal-bonded grindstone. Therefore, grooves 12a of any cross-sectional shape can be formed on the grooved grindstone 12 being dressed by the dressing grindstone 11. This allows machining of workpieces 2 with various cross-sectional shapes without replacing the grindstone. Furthermore, after dressing the grooved grindstone 12, the workpiece 2 can be machined once, and the cross-sectional shape of the machined workpiece 2 can be measured and compared with the target shape to provide feedback. Even if the cross-sectional shape of the machined workpiece 2 differs from the target shape, the cross-sectional shape of the shaped dressing grindstone 11 can be modified (corrected) using the convex grinding portion 9b of the grindstone 9, and the grooved grindstone 12 can be re-dressed using the dressing grindstone 11 with the modified cross-sectional shape. This allows the cross-sectional shape of the workpiece 2 shaped by the grooved grindstone 12 to approach the target shape. In the aforementioned conventional workpiece processing apparatus, a metal-bonded grindstone having a formed groove is used. Therefore, even if the cross-sectional shape of the processed workpiece differs from the target shape, it is impossible to change (correct) the cross-sectional shape of the dressing grindstone 11. However, according to the method of the present invention, the accuracy of the cross-sectional shape of the processed workpiece, that is, the processing accuracy of the workpiece 2, can be significantly improved.

[0095] Next, a fourth embodiment of the present invention will be described. Figure 13: is a front view schematically showing the workpiece processing device of the present embodiment. The workpiece processing device of the present embodiment has a grooved grindstone 12 that is arranged obliquely in the tangential direction relative to the outer periphery of the disk-shaped workpiece 2, the same as in the third embodiment. The grindstone 9, the same as in the second embodiment, is mounted on the grindstone support mechanism 7 and can rotate around the rotation axis 6. The workpiece 2 is mounted on the workpiece support mechanism 4 and can rotate around the rotation axis 3, and can move in a plane parallel to the workpiece 2 and the grindstone 9 (in a plane orthogonal to the rotation axis 3 and the rotation axis 6) in a direction approaching the grindstone 9 and in a direction separating from the grindstone 9, and can move in a plane orthogonal to the grindstone 9 and the workpiece 2 (in a plane parallel to the rotation axis 3 and the rotation axis 6) in a direction approaching the grindstone 9 and in a direction separating from the grindstone 9. As Figure 13 As shown in the figure, the workpiece support mechanism 4 includes an X-direction moving table 4a, a Y-direction moving table 4b, a Z-direction moving table 4c and a motor 4d. The X-direction moving table 4a can move in a plane parallel to the grinding stone 9 and the workpiece 2 in the width direction (with respect to the grinding stone 9 and the workpiece 2) and the width direction (with respect to the grinding stone 9 and the workpiece 2). Figure 13 The Y-direction moving table 4b is mounted on the X-direction moving table 4a and can move in the direction of approach and separation of the grinding stone 9 and the workpiece 2 ( Figure 13 The Z-direction moving table 4c is mounted on the Y-direction moving table 4b and can move in the height direction ( Figure 13 (up and down directions). Although not described in detail, the X-direction moving table 4a, the Y-direction moving table 4b and the Z-direction moving table 4c respectively have a well-known guiding mechanism (such as an LM guide) and a moving mechanism (such as a ball screw and a nut and a rotation drive mechanism), and are capable of moving in the aforementioned directions. The motor 4d is mounted on the Z-direction moving table 4c, and is a driving mechanism that supports the workpiece 2 via the rotating shaft 3 and rotates the rotating shaft 3. The motor 4d is a heat-generating component, and a temperature adjustment mechanism 15 is provided in a manner covering at least one of the motor 4d and the rotating shaft 3. The temperature adjustment mechanism 15 adjusts the temperature of at least one of the motor 4d and the rotating shaft 3 by flowing liquid or gas into a flow path not shown in the figure.

[0096] According to this workpiece processing device, the effects of the first to third embodiments described above can be achieved. In addition, although not shown, the dressing grindstone 11, which is the same as that in the third embodiment, can be moved so as to abut against the grooved grindstone 12 while rotating, thereby easily, efficiently, and accurately dressing the grooved grindstone 12.

[0097] The workpiece support mechanism 4 does not always rotate the workpiece 2 at high speed; it may rotate at low speed or not rotate the workpiece 2 at all. Specifically, when grinding the workpiece 2 using the convex grinding portions 5b, 8b, and 9b of the grinding stones 5, 8, and 9, or the rectangular cross-sectional grinding portion 9f, the workpiece 2 rotates at high speed. When grinding the workpiece 2 using the grooved grinding stone 12, which is tilted tangentially to the outer periphery of the circular plate-shaped workpiece 2, the workpiece 2 rotates at low speed. Furthermore, the workpiece support mechanism 4 does not need to rotate when the workpiece 2 is replaced. Conventionally, when machining multiple workpieces 2 continuously, the workpiece support mechanism 4 repeatedly rotates the workpiece 2 around the rotating shaft 3, rotating it at high speed, then rotating it at low speed, and then stopping the rotation. The workpiece support mechanism 4 generates heat and reaches a high temperature during high-speed rotation of the workpiece 2. During low-speed rotation, the workpiece 2 becomes cooler than during high-speed rotation, and even cooler during the stopped rotation. As a result of these repeated temperature changes in the workpiece support mechanism 4, deformations such as expansion and contraction, particularly in the rotating shaft 3, occur. If the rotating shaft 3 to which the workpiece 2 is mounted deforms and the position of the workpiece 2 in the thickness direction changes, machining accuracy will be significantly reduced even if the workpiece 2 and the grindstone are relatively moved by numerical control as described above.

[0098] Therefore, in each embodiment of the present invention, a temperature adjustment mechanism 15 is provided in conjunction with the workpiece support mechanism 4. The temperature adjustment mechanism 15 generates a flow of liquid or gas to reduce temperature fluctuations of the rotating shaft 3 of the workpiece support mechanism 4, thereby suppressing deformation of the rotating shaft 3. Thus, during machining of the workpiece 2, thermal deformation of the rotating shaft 3 is suppressed, thereby preventing a decrease in machining accuracy of the workpiece 2.

[0099] Furthermore, to maintain the temperature of the rotating shaft 3 as constant as possible, it is preferable to continuously rotate the rotating shaft 3. For example, it is preferable that the workpiece support mechanism 4 continue to rotate the rotating shaft 3 even when the workpiece 2 is being replaced or replenished, or when machining of the workpiece 2 is interrupted due to a problem in the operation process. By maintaining the workpiece support mechanism 4 in a state in which the workpiece 2 is not mounted and machining is not being performed, while rotating the rotating shaft 3 (hereinafter referred to as an idling state or preliminary rotation operation for convenience), temperature fluctuations can be minimized, making it easier to stabilize the temperature in a short period of time. Furthermore, in this preliminary rotation operation, rather than performing only high-speed rotation or only low-speed rotation, it is preferable to alternately repeat high-speed rotation (rotation at the same speed as the workpiece 2 during high-speed rotation during machining by the grindstone) and low-speed rotation (rotation at the same speed as the workpiece 2 during low-speed rotation during machining by the grindstone) in the same manner as during actual machining of the workpiece 2. This minimizes temperature fluctuations. As a result, when transitioning from the preparatory rotational action to the machining of the workpiece 2, the temperature of the rotating shaft 3 can be immediately stabilized, enabling high-precision machining. In particular, aligning the ratio of the duration of high-speed rotation to the duration of low-speed rotation during the preparatory rotational action with the ratio of the duration of high-speed rotation to the duration of low-speed rotation during the actual machining of the workpiece 2 is preferable because temperature management based on the actual machining of the workpiece 2 can be performed. However, if the duration of high-speed rotation and the duration of low-speed rotation during the preparatory rotational action are long, the waiting time required to wait for the appropriate time to terminate the preparatory rotational action and transition to machining of the workpiece 2 (e.g., the timing to switch the rotation speed of the preparatory rotational action) when the actual machining of the workpiece 2 begins becomes longer, potentially reducing operating efficiency. Therefore, as described above, it is preferable to make the ratio of the duration of high-speed rotation to the duration of low-speed rotation during the preparatory rotation operation consistent with the ratio of the duration of high-speed rotation to the duration of low-speed rotation during the actual machining of the workpiece 2, and to make the duration of high-speed rotation and the duration of low-speed rotation during the preparatory rotation operation shorter than the duration of high-speed rotation and the duration of low-speed rotation during the actual machining of the workpiece 2. Thus, by temperature management based on the actual machining of the workpiece 2, the temperature change of the rotating shaft 3 is minimized, thereby suppressing a decrease in machining accuracy. Furthermore, the standby time when transitioning from the preparatory rotation operation to the machining of the workpiece 2 can be shortened, thereby suppressing a decrease in working efficiency.

[0100] In the grinding stones 5, 8, and 9 of the present invention, the cross-sectional shape of the convex grinding portion 5b, 8b, and 9b in the cross section passing through the rotation axis 6 of the grinding stones 5, 8, and 9 is a shape having a pair of arc-shaped portions 5e, 8e, and 9e located at both ends in the thickness direction. When the arc-shaped portions 5e and 9e located at both ends in the thickness direction are connected by the same arc-shaped portion, the convex grinding portion 5b and 9b are as follows. Figures 1 to 3D , 9A to 9C, 11A to 13 have a cross-sectional shape as a whole forming a semicircular shape. Figures 10A-10B As shown, the convex grinding portion 8b can also be configured with a cross-sectional shape in which arc-shaped portions 8e at both ends in the thickness direction are connected by a straight portion 8f. In either case, it is preferred that the arc-shaped portion 5e, 8e, 9e at one end in the thickness direction of the grinding stone 5, 8, or 9 and the arc-shaped portion 5e, 8e, 9e at the other end are separately formed so that the average value of their respective radii of curvature is the desired size. This allows both ends in the thickness direction and the other end to be formed with high precision and good quality, compared to a case where the convex grinding portion 5b, 8b, or 9b is processed so that the entire portion has the same radius of curvature. Furthermore, it is preferred that the errors in the radii of curvature of the arc-shaped portion 5e, 8e, 9e at one end in the thickness direction and the other end in the thickness direction are each minimized to a certain extent. For example, the difference between the maximum and minimum values ​​of the radius of curvature of the arcuate portions 5e, 8e, and 9e at one end in the thickness direction and the difference between the maximum and minimum values ​​of the radius of curvature of the arcuate portions 5e, 8e, and 9e at the other end are both within an allowable range, that is, less than a predetermined value (first predetermined value). In addition, the difference between the average value of the radius of curvature of the arcuate portions 5e, 8e, and 9e at one end in the thickness direction and the average value of the radius of curvature of the arcuate portions 5e, 8e, and 9e at the other end is also within an allowable range, that is, less than a predetermined value (second predetermined value).

[0101] [Note 1]

[0102] A workpiece processing device for forming a disk-shaped workpiece into a desired cross-sectional shape.

[0103] The workpiece processing device is characterized in that:

[0104] The workpiece processing device includes a workpiece supporting mechanism for supporting the workpiece, a disc-shaped grindstone arranged parallel to the workpiece, and a grindstone supporting mechanism for supporting the grindstone.

[0105] The workpiece support mechanism rotates the workpiece, and the grindstone support mechanism rotates the grindstone, wherein a rotation axis serving as a center of rotation of the workpiece by the workpiece support mechanism and a rotation axis serving as a center of rotation of the grindstone by the grindstone support mechanism are parallel to each other.

[0106] The grindstone has a convex grinding portion on its outer periphery, wherein the cross-sectional shape of the convex grinding portion in a cross section passing through the rotation axis of the grindstone is convex toward the outer periphery and has arc-shaped portions at both ends in at least the thickness direction.

[0107] The grinding stone and the workpiece can move relative to each other in a manner of approaching or separating from each other through the grinding stone support mechanism or the workpiece support mechanism.

[0108] The grinding stone supporting mechanism or the workpiece supporting mechanism moves the grinding stone relative to the workpiece according to a movement condition calculated based on a curvature radius of the arc-shaped portion of the grinding stone so that a contact portion between the convex grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece.

[0109] The convex grinding portion and a rectangular grinding portion having a surface facing the workpiece and a straight line parallel to the thickness direction of the grinding stone are arranged on the outer periphery of the grinding stone in the thickness direction. The rectangular grinding portion of the grinding stone is a portion that contacts the outer periphery of the workpiece and grinds the workpiece so as to reduce the radius of the workpiece as the grinding stone moves from the outer side to the inner side in the radial direction of the workpiece.

[0110] The radius of curvature of the arcuate portion of the grindstone is at least 10 times the thickness of the workpiece so that the arcuate portion of the grindstone contacts the workpiece with substantially no gap therebetween.

[0111] [Note 2]

[0112] The workpiece processing device according to Supplementary Note 1, wherein:

[0113] The grinding stone supporting mechanism and the workpiece supporting mechanism are configured such that, when grinding the outer peripheral portion of one surface side of the workpiece, the workpiece and the grinding stone are rotated, and the arc-shaped portion of the convex grinding portion of the grinding stone is moved relative to the workpiece in a curved line at a pre-calculated angle from the outer peripheral end surface of the workpiece toward one surface according to the movement condition. When grinding the outer peripheral portion of the other surface side of the workpiece, the workpiece and the grinding stone are rotated, and the arc-shaped portion of the convex grinding portion of the grinding stone is moved relative to the workpiece in a curved line at a pre-calculated angle from the outer peripheral end surface of the workpiece toward the other surface according to the movement condition.

[0114] The grinding stone supporting mechanism and the workpiece supporting mechanism are configured to cause the workpiece and the grinding stone to rotate while the arc-shaped portion of the convex grinding portion of the grinding stone is moved relative to the workpiece in a curved manner at a pre-calculated angle from the outer peripheral end surface of the workpiece toward the one surface or the other surface according to the movement conditions when performing rough grinding of the outer peripheral portion of the one surface side or the other surface side of the workpiece, and then stop the relative movement of the grinding stone with respect to the workpiece.

[0115] When the grinding stone supporting mechanism and the workpiece supporting mechanism are performing precision grinding of the outer peripheral portion of the one surface side or the other surface side of the workpiece, the workpiece and the grinding stone are rotated, and the arc-shaped portion of the convex grinding portion of the grinding stone is moved relative to the workpiece in a curved manner at a pre-calculated angle from the outer peripheral end surface of the workpiece toward the one surface or the other surface according to the movement conditions, and then the grinding stone is moved relative to the workpiece in a straight line.

[0116] [Note 3]

[0117] The workpiece processing device according to Supplement 1 or 2, wherein:

[0118] The ground portion having a rectangular cross section has a smaller radial dimension than the convex ground portion and is provided in close contact with the convex ground portion.

[0119] [Note 4]

[0120] The workpiece processing device according to any one of Supplementary Notes 1 to 3, wherein:

[0121] In addition to the grindstone having the convex grinding portion, the workpiece processing device further comprises a circular plate-shaped grooved grindstone arranged obliquely with respect to a tangential direction of the outer periphery of the workpiece and used for grinding more precisely than the grinding performed by the convex grinding portion of the grindstone, and a grooved grindstone support mechanism for supporting the grooved grindstone.

[0122] The grooved grindstone supporting mechanism rotates the grooved grindstone.

[0123] [Note 5]

[0124] A workpiece processing device for forming a disk-shaped workpiece into a desired cross-sectional shape.

[0125] The workpiece processing device is characterized in that:

[0126] The workpiece processing device includes a workpiece supporting mechanism for supporting the workpiece, a disc-shaped grindstone arranged parallel to the workpiece, and a grindstone supporting mechanism for supporting the grindstone.

[0127] The workpiece support mechanism rotates the workpiece, and the grindstone support mechanism rotates the grindstone, wherein a rotation axis serving as a center of rotation of the workpiece by the workpiece support mechanism and a rotation axis serving as a center of rotation of the grindstone by the grindstone support mechanism are parallel to each other.

[0128] The grindstone has a convex grinding portion on its outer periphery, wherein the cross-sectional shape of the convex grinding portion in a cross section passing through the rotation axis of the grindstone is convex toward the outer periphery and has arc-shaped portions at both ends in at least the thickness direction.

[0129] The grinding stone and the workpiece can move relative to each other in a manner of approaching or separating from each other through the grinding stone support mechanism or the workpiece support mechanism.

[0130] The grinding stone supporting mechanism or the workpiece supporting mechanism moves the grinding stone relative to the workpiece according to a movement condition calculated based on a curvature radius of the arc-shaped portion of the grinding stone so that a contact portion between the convex grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece.

[0131] In addition to the grindstone having the convex grinding portion, the workpiece processing device further comprises a circular plate-shaped grooved grindstone arranged obliquely with respect to a tangential direction of the outer periphery of the workpiece and used for grinding more precisely than the grinding performed by the convex grinding portion of the grindstone, and a grooved grindstone support mechanism for supporting the grooved grindstone.

[0132] The grooved grindstone supporting mechanism rotates the grooved grindstone.

[0133] The workpiece processing device further includes a dressing grindstone that can be mounted on the workpiece support mechanism instead of the workpiece.

[0134] The dressing grindstone is formed into an outer shape by relatively moving the dressing grindstone according to the movement conditions using the grindstone support mechanism or the workpiece support mechanism.

[0135] The grooved grindstone is pressed against the dressing grindstone and transfers the outer shape of the dressing grindstone, thereby forming or shaping the grooves.

[0136] [Note 6]

[0137] The workpiece processing device according to any one of Supplementary Notes 1 to 5, wherein:

[0138] The cross-sectional shape of the convex grinding portion in a cross section passing through the rotation axis of the grindstone is a semicircular shape or a shape having a pair of arc-shaped portions located at both ends in the thickness direction and a straight portion located between the pair of arc-shaped portions.

[0139] [Note 7]

[0140] The workpiece processing device according to any one of Supplementary Notes 1 to 6, wherein:

[0141] The workpiece support mechanism includes a temperature adjustment mechanism that generates a flow of liquid or gas for maintaining a constant temperature of the rotation shaft of the workpiece support mechanism.

[0142] [Note 8]

[0143] A grinding stone is included in a workpiece processing device, the workpiece processing device having a workpiece supporting mechanism that supports a disc-shaped workpiece, a disc-shaped grinding stone arranged parallel to the workpiece, and a grinding stone supporting mechanism that supports the grinding stone, the workpiece supporting mechanism rotating the workpiece, the grinding stone supporting mechanism rotating the grinding stone, the rotation axis serving as the center of rotation of the workpiece by the workpiece supporting mechanism and the rotation axis serving as the center of rotation of the grinding stone by the grinding stone supporting mechanism being parallel to each other, the grinding stone having a convex grinding portion on its outer periphery, the cross section of the convex grinding portion in a cross section passing through the rotation axis of the grinding stone being parallel to each other The shape is convex toward the outer peripheral side and has arc-shaped portions at both ends at least in the thickness direction. The grinding stone and the workpiece can be relatively moved so as to approach or separate from each other by the grinding stone support mechanism or the workpiece support mechanism. The grinding stone support mechanism or the workpiece support mechanism moves the grinding stone relative to the workpiece according to movement conditions calculated based on the curvature radius of the arc-shaped portion of the grinding stone so that the contact portion between the convex grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece. The workpiece processing device is used to form the workpiece into the desired cross-sectional shape.

[0144] The grinding stone is characterized in that

[0145] The cross-sectional shape of the convex grinding portion in a cross section passing through the rotation axis of the grindstone is a shape having a pair of arc-shaped portions located at both ends in the thickness direction and a straight portion located between the pair of arc-shaped portions.

[0146] The straight portion is a portion where the grinding stone has a coarser grain size than the arc-shaped portion, and the arc-shaped portion is used for grinding more precisely than the grinding performed by the straight portion.

[0147] The radius of curvature of the arc-shaped portion is at least 10 times the thickness of the workpiece so that the arc-shaped portion contacts the workpiece substantially without any gap therebetween.

[0148] [Note 9]

[0149] A grinding stone, which is included in the workpiece processing device described in any one of Supplementary Notes 1 to 3,

[0150] The grinding stone is characterized in that

[0151] The cross-sectional rectangular grinding portion is a portion having a grinding stone with a coarser grain size than the convex grinding portion, and the convex grinding portion is a portion used for grinding more precisely than the grinding performed by the cross-sectional rectangular grinding portion.

[0152] [Note 10]

[0153] A grinding stone, which is included in the workpiece processing device described in any one of Supplementary Notes 1 to 7,

[0154] The grinding stone is characterized in that

[0155] The arc-shaped portion at one end portion in the thickness direction and the arc-shaped portion at the other end portion are portions that are separately formed so that the average value of their respective curvature radii becomes a desired value.

[0156] [Note 11]

[0157] A grinding stone, which is included in the workpiece processing device described in any one of Supplementary Notes 1 to 7,

[0158] The grinding stone is characterized in that

[0159] The difference between the maximum and minimum values ​​of the curvature radius of the arc-shaped portion at one end in the thickness direction and the difference between the maximum and minimum values ​​of the curvature radius of the arc-shaped portion at the other end are both less than a first predetermined value.

[0160] A difference between an average value of the curvature radius of the arc-shaped portion at one end portion in the thickness direction and an average value of the curvature radius of the arc-shaped portion at the other end portion is equal to or smaller than a second predetermined value.

[0161] [Note 12]

[0162] A grinding stone, which is included in the workpiece processing device described in any one of Supplementary Notes 1 to 7,

[0163] The grinding stone is characterized in that

[0164] The grindstone has a straight or tapered mounting hole extending in the thickness direction.

[0165] [Note 13]

[0166] A workpiece processing method for forming a disc-shaped workpiece into a desired cross-sectional shape using a grinding stone, wherein the grinding stone has a convex grinding portion on its outer periphery and is rotatable and disc-shaped, wherein the cross-sectional shape of the convex grinding portion in a section passing through the rotation axis of the grinding stone is convex toward the outer periphery and has arc-shaped portions at both ends in at least the thickness direction.

[0167] The workpiece processing method is characterized by comprising:

[0168] a step of arranging the workpiece and the grindstone parallel to each other; and

[0169] while rotating the grindstone and rotating the workpiece about a rotation axis parallel to the rotation axis of the grindstone, the grindstone is moved relative to the workpiece according to movement conditions calculated based on the curvature radius of the arc-shaped portion of the grindstone so that the contact portion between the convex grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece;

[0170] The step of moving the grinding stone relative to the workpiece comprises:

[0171] While the workpiece and the grindstone are being rotated, the arcuate portion of the convex grinding portion of the grindstone is moved relative to the workpiece in a curved manner at a pre-calculated angle from the outer peripheral end surface of the workpiece toward one surface in accordance with the movement conditions, thereby grinding the outer peripheral portion of the one surface side of the workpiece;

[0172] moving the grinding stone relative to the workpiece from the one surface side to the other surface side along the outer peripheral end surface of the workpiece; and

[0173] While the workpiece and the grindstone are being rotated, the arc-shaped portion of the convex grinding portion of the grindstone is moved relative to the workpiece in a curved manner at a pre-calculated angle from the outer peripheral end surface of the workpiece toward the other surface according to the movement conditions, thereby grinding the outer peripheral portion of the other surface side of the workpiece.

[0174] When performing rough grinding of the outer peripheral portion of the one surface side or the other surface side of the workpiece, the arc-shaped portion of the convex grinding portion of the grinding stone is moved relative to the workpiece in a curved manner at a pre-calculated angle from the outer peripheral end surface of the workpiece toward the one surface or the other surface according to the movement conditions while the workpiece and the grinding stone are rotated, and then the relative movement of the grinding stone with respect to the workpiece is stopped.

[0175] When performing precision grinding of the outer periphery of the one surface side or the other surface side of the workpiece, while the workpiece and the grinding stone are rotated, the arc-shaped portion of the convex grinding portion of the grinding stone is moved relative to the workpiece in a curved manner at a pre-calculated angle from the outer peripheral end face of the workpiece toward the one surface or the other surface according to the movement conditions, and then the grinding stone is moved relative to the workpiece in a straight line.

[0176] [Note 14]

[0177] A workpiece processing method for forming a disc-shaped workpiece into a desired cross-sectional shape using a grinding stone, wherein the grinding stone has a convex grinding portion on its outer periphery and is rotatable and disc-shaped, wherein the cross-sectional shape of the convex grinding portion in a section passing through the rotation axis of the grinding stone is convex toward the outer periphery and has arc-shaped portions at both ends in at least the thickness direction.

[0178] The workpiece processing method is characterized by comprising:

[0179] a step of arranging the workpiece and the grindstone parallel to each other; and

[0180] while rotating the grindstone and rotating the workpiece about a rotation axis parallel to the rotation axis of the grindstone, the grindstone is moved relative to the workpiece according to movement conditions calculated based on the curvature radius of the arc-shaped portion of the grindstone so that the contact portion between the convex grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece;

[0181] The workpiece processing method includes adjusting the temperature of the rotating axis of the workpiece by using the flow of liquid or gas,

[0182] Before machining the workpiece, a preliminary rotation operation is performed in which the rotation axis, which serves as the rotation center when the workpiece is rotated, is rotated without the workpiece being mounted.

[0183] In the preparatory rotation operation, high-speed rotation at the same speed as the high-speed rotation of the workpiece during processing by the grindstone and low-speed rotation at the same speed as the low-speed rotation of the workpiece during processing by the grindstone are repeated alternately.

[0184] The ratio of the duration of the high-speed rotation to the duration of the low-speed rotation in the preparatory rotation operation is made consistent with the ratio of the duration of the high-speed rotation to the duration of the low-speed rotation of the workpiece during machining by the grindstone.

[0185] The duration of the high-speed rotation and the duration of the low-speed rotation in the preparatory rotation operation are respectively shorter than the duration of the high-speed rotation and the duration of the low-speed rotation of the workpiece during machining by the grindstone.

[0186] [Note 15]

[0187] The workpiece processing method according to Supplementary Note 13 or 14, wherein:

[0188] The cross-sectional shape of the convex grinding portion in a cross section passing through the rotation axis of the grindstone is a semicircular shape.

[0189] [Note 16]

[0190] The workpiece processing method according to Supplementary Note 13 or 14, wherein:

[0191] The cross-sectional shape of the convex grinding portion in a cross section passing through the rotation axis of the grindstone is a shape having a pair of arc-shaped portions located at both ends in the thickness direction and a straight portion located between the pair of arc-shaped portions.

[0192] The straight portion is used to at least perform processing to reduce the diameter of the workpiece by making the straight portion abut against the outer peripheral end surface of the workpiece, and the arc-shaped portion is used to at least perform processing to form the workpiece into the desired cross-sectional shape by making the arc-shaped portion abut against one surface and the other surface of the workpiece respectively.

[0193] [Note 17]

[0194] The workpiece processing method according to Supplementary Note 13 or 14, wherein:

[0195] The convex grinding portion and the rectangular grinding portion having a straight cross-section parallel to the thickness direction of the grinding stone in a cross section along the rotation axis are arranged on the outer periphery of the grinding stone in the thickness direction.

[0196] The rectangular cross-sectional grinding portion is used to at least perform processing in which the rectangular cross-sectional grinding portion is brought into contact with the outer peripheral end surface of the workpiece and the grinding stone is moved from the radial outer side toward the inner side of the workpiece to reduce the diameter of the workpiece. The convex grinding portion is used to at least perform processing in which the convex grinding portion is brought into contact with one surface and the other surface of the workpiece to form the workpiece into the desired cross-sectional shape.

[0197] [Note 18]

[0198] The workpiece processing method according to Supplementary Note 16 or 17, wherein:

[0199] In the process of forming the workpiece into the desired cross-sectional shape, grinding is performed that is more precise than the grinding in the process of reducing the diameter of the workpiece.

[0200] [Note 19]

[0201] The workpiece processing method according to any one of Supplementary Notes 13 to 17, wherein:

[0202] In addition to the grinding stone, there is also a disc-shaped grooved grinding stone arranged obliquely with respect to the tangential direction of the outer periphery of the workpiece.

[0203] After the convex grinding portion of the grindstone is brought into contact with the workpiece to grind the workpiece, the inner peripheral surface of the groove of the grooved grindstone is brought into contact with the workpiece to perform grinding more precisely than the grinding performed by the convex grinding portion.

[0204] [Note 20]

[0205] A workpiece processing method for forming a disc-shaped workpiece into a desired cross-sectional shape using a grinding stone, wherein the grinding stone has a convex grinding portion on its outer periphery and is rotatable and disc-shaped, wherein the cross-sectional shape of the convex grinding portion in a section passing through the rotation axis of the grinding stone is convex toward the outer periphery and has arc-shaped portions at both ends in at least the thickness direction.

[0206] The workpiece processing method is characterized by comprising:

[0207] a step of arranging the workpiece and the grindstone parallel to each other; and

[0208] while rotating the grindstone and rotating the workpiece about a rotation axis parallel to the rotation axis of the grindstone, the grindstone is moved relative to the workpiece according to movement conditions calculated based on the curvature radius of the arc-shaped portion of the grindstone so that the contact portion between the convex grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece;

[0209] In addition to the grinding stone, there is also a disc-shaped grooved grinding stone arranged obliquely with respect to the tangential direction of the outer periphery of the workpiece.

[0210] After the convex grinding portion of the grindstone is brought into contact with the workpiece to grind the workpiece, the inner peripheral surface of the groove of the grooved grindstone is brought into contact with the workpiece to perform grinding more precisely than the grinding performed by the convex grinding portion.

[0211] The workpiece processing method includes, before the step of arranging the workpiece and the circular plate-shaped grinding stone parallel to each other, the steps of arranging a circular plate-shaped dressing grinding stone parallel to the grinding stone, rotating the grinding stone about a rotation axis parallel to the rotation axis of the grinding stone, moving the grinding stone relative to the dressing grinding stone to form the outer shape of the dressing grinding stone, and pressing the material of the grooved grinding stone against the dressing grinding stone to transfer the outer shape of the dressing grinding stone to form or shape the grooves.

[0212] In the step of transferring the outer shape of the dressing grindstone to form or shape the groove, the groove is formed into a shape predetermined so that the workpiece abutting against the inner peripheral surface of the groove is formed into the desired cross-sectional shape.

[0213] In the step of forming the outer shape of the dressing grindstone, a movement condition is calculated in advance based on the curvature radius of the arc-shaped portion of the grinding stone, in which a contact portion between the convex grinding portion of the grinding stone and the dressing grindstone moves along a shape corresponding to the predetermined shape of the groove. In the step of forming the outer shape of the dressing grindstone, the dressing grindstone is moved relative to the grinding stone in accordance with the movement condition.

[0214] Description of Reference Numerals

[0215] 1 Workpiece processing device

[0216] 2 Workpiece

[0217] 2a Chamfered part

[0218] 3, 6, 14 rotation axes

[0219] 4 Workpiece support mechanism

[0220] 4a X-direction moving stage

[0221] 4b Y-direction moving stage

[0222] 4c Z-direction moving stage

[0223] 4D motor

[0224] 5, 8, 9 grinding stones

[0225] 5a, 8a, 9a: Base circular plate

[0226] 5b, 8b, 9b convex grinding part

[0227] 5c, 8c, 9c mounting holes

[0228] 5d, 8d, 9d concave part

[0229] 5e, 8e, 9e arc-shaped part

[0230] 7 Grinding stone support mechanism

[0231] 8f straight line part

[0232] 9f Grinding part with rectangular cross section

[0233] 11 Dressing Grinding Stone (Dressing Part)

[0234] 12 Grooved grinding stone

[0235] Slot 12a

[0236] 13 Grooved grinding stone support mechanism

[0237] 15. Temperature adjustment mechanism

[0238] 16 Grindstone

[0239] 16a forming groove.

Claims

1. A workpiece processing device for forming a disk-shaped workpiece into a desired cross-sectional shape, The workpiece processing device is characterized in that: The workpiece processing device includes a workpiece supporting mechanism for supporting the workpiece, a disc-shaped grindstone arranged parallel to the workpiece, and a grindstone supporting mechanism for supporting the grindstone. The workpiece support mechanism rotates the workpiece, and the grindstone support mechanism rotates the grindstone, wherein a rotation axis serving as a center of rotation of the workpiece by the workpiece support mechanism and a rotation axis serving as a center of rotation of the grindstone by the grindstone support mechanism are parallel to each other. The grindstone has a convex grinding portion on its outer periphery, wherein the cross-sectional shape of the convex grinding portion in a cross section passing through the rotation axis of the grindstone is convex toward the outer periphery and has arc-shaped portions at both ends in at least the thickness direction. The grinding stone and the workpiece can move relative to each other in a manner of approaching or separating from each other through the grinding stone support mechanism or the workpiece support mechanism. The grinding stone supporting mechanism or the workpiece supporting mechanism moves the grinding stone relative to the workpiece according to a movement condition calculated based on a curvature radius of the arc-shaped portion of the grinding stone so that a contact portion between the convex grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece. The convex grinding portion and a rectangular grinding portion having a surface facing the workpiece and a straight line parallel to the thickness direction of the grinding stone are arranged on the outer periphery of the grinding stone in the thickness direction. The rectangular grinding portion of the grinding stone is a portion that contacts the outer periphery of the workpiece and grinds the workpiece so as to reduce the radius of the workpiece as the grinding stone moves from the outer side to the inner side in the radial direction of the workpiece. The radius of curvature of the arcuate portion of the grindstone is at least 10 times the thickness of the workpiece, so that the arcuate portion of the grindstone abuts against the workpiece with substantially no gap therebetween. The workpiece support mechanism includes a temperature adjustment mechanism that generates a flow of liquid or gas for maintaining a constant temperature of the rotation shaft of the workpiece support mechanism.

2. The workpiece processing device according to claim 1, wherein: The grinding stone supporting mechanism and the workpiece supporting mechanism are configured such that, when grinding the outer peripheral portion of one surface side of the workpiece, the workpiece and the grinding stone are rotated, and the arc-shaped portion of the convex grinding portion of the grinding stone is moved relative to the workpiece in a curved line at a pre-calculated angle from the outer peripheral end surface of the workpiece toward one surface according to the movement condition. When grinding the outer peripheral portion of the other surface side of the workpiece, the workpiece and the grinding stone are rotated, and the arc-shaped portion of the convex grinding portion of the grinding stone is moved relative to the workpiece in a curved line at a pre-calculated angle from the outer peripheral end surface of the workpiece toward the other surface according to the movement condition. The grinding stone supporting mechanism and the workpiece supporting mechanism are configured to cause the workpiece and the grinding stone to rotate while the arc-shaped portion of the convex grinding portion of the grinding stone is moved relative to the workpiece in a curved manner at a pre-calculated angle from the outer peripheral end surface of the workpiece toward the one surface or the other surface according to the movement conditions when performing rough grinding of the outer peripheral portion of the one surface side or the other surface side of the workpiece, and then stop the relative movement of the grinding stone with respect to the workpiece. When the grinding stone supporting mechanism and the workpiece supporting mechanism are performing precision grinding of the outer peripheral portion of the one surface side or the other surface side of the workpiece, the workpiece and the grinding stone are rotated, and the arc-shaped portion of the convex grinding portion of the grinding stone is moved relative to the workpiece in a curved manner at a pre-calculated angle from the outer peripheral end surface of the workpiece toward the one surface or the other surface according to the movement conditions, and then the grinding stone is moved relative to the workpiece in a straight line.

3. The workpiece processing device according to claim 1, wherein: The ground portion having a rectangular cross section has a smaller radial dimension than the convex ground portion and is provided in close contact with the convex ground portion.

4. The workpiece processing device according to claim 1, wherein: In addition to the grindstone having the convex grinding portion, the workpiece processing device further comprises a circular plate-shaped grooved grindstone arranged obliquely with respect to a tangential direction of the outer periphery of the workpiece and used for grinding more precisely than the grinding performed by the convex grinding portion of the grindstone, and a grooved grindstone support mechanism for supporting the grooved grindstone. The grooved grindstone supporting mechanism rotates the grooved grindstone.

5. A workpiece processing device for forming a disk-shaped workpiece into a desired cross-sectional shape, The workpiece processing device is characterized in that: The workpiece processing device includes a workpiece supporting mechanism for supporting the workpiece, a disc-shaped grindstone arranged parallel to the workpiece, and a grindstone supporting mechanism for supporting the grindstone. The workpiece support mechanism rotates the workpiece, and the grindstone support mechanism rotates the grindstone, wherein a rotation axis serving as a center of rotation of the workpiece by the workpiece support mechanism and a rotation axis serving as a center of rotation of the grindstone by the grindstone support mechanism are parallel to each other. The grindstone has a convex grinding portion on its outer periphery, wherein the cross-sectional shape of the convex grinding portion in a cross section passing through the rotation axis of the grindstone is convex toward the outer periphery and has arc-shaped portions at both ends in at least the thickness direction. The grinding stone and the workpiece can move relative to each other in a manner of approaching or separating from each other through the grinding stone support mechanism or the workpiece support mechanism. The grinding stone supporting mechanism or the workpiece supporting mechanism moves the grinding stone relative to the workpiece according to a movement condition calculated based on a curvature radius of the arc-shaped portion of the grinding stone so that a contact portion between the convex grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece. In addition to the grindstone having the convex grinding portion, the workpiece processing device further comprises a circular plate-shaped grooved grindstone arranged obliquely with respect to a tangential direction of the outer periphery of the workpiece and used for grinding more precisely than the grinding performed by the convex grinding portion of the grindstone, and a grooved grindstone support mechanism for supporting the grooved grindstone. The grooved grindstone supporting mechanism rotates the grooved grindstone. The workpiece processing device further includes a dressing grindstone that can be mounted on the workpiece support mechanism instead of the workpiece. The dressing grindstone is formed into an outer shape by relatively moving the dressing grindstone according to the movement conditions using the grindstone support mechanism or the workpiece support mechanism. The grooved grindstone is pressed against the dressing grindstone and transfers the outer shape of the dressing grindstone, thereby forming or shaping the grooves.

6. The workpiece processing device according to any one of claims 1 to 5, wherein: The cross-sectional shape of the convex grinding portion in a cross section passing through the rotation axis of the grindstone is a semicircular shape or a shape having a pair of arc-shaped portions located at both ends in the thickness direction and a straight portion located between the pair of arc-shaped portions.

7. A grinding stone included in a workpiece processing device, the workpiece processing device comprising a workpiece supporting mechanism for supporting a disc-shaped workpiece, the disc-shaped grinding stone arranged parallel to the workpiece, and a grinding stone supporting mechanism for supporting the grinding stone, the workpiece supporting mechanism rotating the workpiece, the grinding stone supporting mechanism rotating the grinding stone, the rotation axis serving as the center of rotation of the workpiece by the workpiece supporting mechanism and the rotation axis serving as the center of rotation of the grinding stone by the grinding stone supporting mechanism being parallel to each other, the grinding stone having a convex grinding portion on its outer periphery, the section of the convex grinding portion in a section passing through the rotation axis of the grinding stone being parallel to each other. The surface shape is convex toward the outer peripheral side and has arc-shaped portions at both ends at least in the thickness direction. The grinding stone and the workpiece can be relatively moved so as to approach or separate from each other by the grinding stone support mechanism or the workpiece support mechanism. The grinding stone support mechanism or the workpiece support mechanism moves the grinding stone relative to the workpiece according to movement conditions calculated based on the curvature radius of the arc-shaped portion of the grinding stone so that the contact portion between the convex grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece. The workpiece processing device is used to form the workpiece into the desired cross-sectional shape. The grinding stone is characterized in that The cross-sectional shape of the convex grinding portion in a cross section passing through the rotation axis of the grindstone is a shape having a pair of arc-shaped portions located at both ends in the thickness direction and a straight portion located between the pair of arc-shaped portions. The straight portion is a portion where the grinding stone has a coarser grain size than the arc-shaped portion, and the arc-shaped portion is used for grinding more precisely than the grinding performed by the straight portion. The radius of curvature of the arc-shaped portion is at least 10 times the thickness of the workpiece, so that the arc-shaped portion abuts against the workpiece without substantially creating a gap between the arc-shaped portion and the chamfered portion of the desired cross-sectional shape of the workpiece. The workpiece support mechanism includes a temperature adjustment mechanism that generates a flow of liquid or gas for maintaining a constant temperature of the rotation shaft of the workpiece support mechanism.

8. A grinding stone, which is included in the workpiece processing device according to any one of claims 1 to 3. The grinding stone is characterized in that The cross-sectional rectangular grinding portion is a portion having a grinding stone with a coarser grain size than the convex grinding portion, and the convex grinding portion is a portion used for grinding more precisely than the grinding performed by the cross-sectional rectangular grinding portion.

9. A grinding stone, which is included in the workpiece processing device according to any one of claims 1 to 6, The grinding stone is characterized in that The arc-shaped portion at one end portion in the thickness direction and the arc-shaped portion at the other end portion are portions that are separately formed so that the average value of their respective curvature radii becomes a desired value.

10. A grinding stone, which is included in the workpiece processing device according to any one of claims 1 to 6, The grinding stone is characterized in that The difference between the maximum and minimum values ​​of the curvature radius of the arc-shaped portion at one end in the thickness direction and the difference between the maximum and minimum values ​​of the curvature radius of the arc-shaped portion at the other end are both less than a first predetermined value. A difference between an average value of the curvature radius of the arc-shaped portion at one end portion in the thickness direction and an average value of the curvature radius of the arc-shaped portion at the other end portion is equal to or smaller than a second predetermined value.

11. A grinding stone, which is included in the workpiece processing device according to any one of claims 1 to 6, The grinding stone is characterized in that The grindstone has a straight or tapered mounting hole extending in the thickness direction.

12. A workpiece processing method for forming a disc-shaped workpiece into a desired cross-sectional shape using a grinding stone, the grinding stone being rotatable and having a disc-shaped portion on its outer periphery, the convex grinding portion having a cross-sectional shape convex toward the outer periphery in a cross section passing through the rotation axis of the grinding stone and having arc-shaped portions at at least both ends in the thickness direction. The workpiece processing method is characterized by comprising: a step of arranging the workpiece and the grindstone parallel to each other; as well as while rotating the grindstone and rotating the workpiece about a rotation axis parallel to the rotation axis of the grindstone, the grindstone is moved relative to the workpiece according to movement conditions calculated based on the curvature radius of the arc-shaped portion of the grindstone so that the contact portion between the convex grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece; The step of moving the grinding stone relative to the workpiece comprises: While the workpiece and the grindstone are being rotated, the arcuate portion of the convex grinding portion of the grindstone is moved relative to the workpiece in a curved manner at a pre-calculated angle from the outer peripheral end surface of the workpiece toward one surface in accordance with the movement conditions, thereby grinding the outer peripheral portion of the one surface side of the workpiece; moving the grinding stone relative to the workpiece from the one surface side to the other surface side along the outer peripheral end surface of the workpiece; and While the workpiece and the grindstone are being rotated, the arc-shaped portion of the convex grinding portion of the grindstone is moved relative to the workpiece in a curved manner at a pre-calculated angle from the outer peripheral end surface of the workpiece toward the other surface according to the movement conditions, thereby grinding the outer peripheral portion of the other surface side of the workpiece. When performing rough grinding of the outer peripheral portion of the one surface side or the other surface side of the workpiece, the arc-shaped portion of the convex grinding portion of the grinding stone is moved relative to the workpiece in a curved manner at a pre-calculated angle from the outer peripheral end surface of the workpiece toward the one surface or the other surface according to the movement conditions while the workpiece and the grinding stone are rotated, and then the relative movement of the grinding stone with respect to the workpiece is stopped. When performing precision grinding of the outer periphery of the one surface side or the other surface side of the workpiece, while the workpiece and the grinding stone are rotated, the arc-shaped portion of the convex grinding portion of the grinding stone is moved relative to the workpiece in a curved manner at a pre-calculated angle from the outer peripheral end face of the workpiece toward the one surface or the other surface according to the movement conditions, and then the grinding stone is moved relative to the workpiece in a straight line.

13. A workpiece processing method for forming a disc-shaped workpiece into a desired cross-sectional shape using a grinding stone, the grinding stone being rotatable and having a disc-shaped portion on its outer periphery, the convex grinding portion having a cross-sectional shape convex toward the outer periphery in a cross section passing through the rotation axis of the grinding stone and having arc-shaped portions at at least both ends in the thickness direction. The workpiece processing method is characterized by comprising: a step of arranging the workpiece and the grindstone parallel to each other; as well as while rotating the grindstone and rotating the workpiece about a rotation axis parallel to the rotation axis of the grindstone, the grindstone is moved relative to the workpiece according to movement conditions calculated based on the curvature radius of the arc-shaped portion of the grindstone so that the contact portion between the convex grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece; The workpiece processing method includes adjusting the temperature of the rotating axis of the workpiece by using the flow of liquid or gas, Before machining the workpiece, a preliminary rotation operation is performed in which the rotation axis, which serves as the rotation center when the workpiece is rotated, is rotated without the workpiece being mounted. In the preparatory rotation operation, high-speed rotation at the same speed as the high-speed rotation of the workpiece during processing by the grindstone and low-speed rotation at the same speed as the low-speed rotation of the workpiece during processing by the grindstone are repeated alternately. The ratio of the duration of the high-speed rotation to the duration of the low-speed rotation in the preparatory rotation operation is made consistent with the ratio of the duration of the high-speed rotation to the duration of the low-speed rotation of the workpiece during machining by the grindstone. The duration of the high-speed rotation and the duration of the low-speed rotation in the preparatory rotation operation are respectively shorter than the duration of the high-speed rotation and the duration of the low-speed rotation of the workpiece during machining by the grindstone.

14. The workpiece processing method according to claim 12 or 13, wherein: The cross-sectional shape of the convex grinding portion in a cross section passing through the rotation axis of the grindstone is a semicircular shape.

15. The workpiece processing method according to claim 12 or 13, wherein: The cross-sectional shape of the convex grinding portion in a cross section passing through the rotation axis of the grindstone is a shape having a pair of arc-shaped portions located at both ends in the thickness direction and a straight portion located between the pair of arc-shaped portions. The straight portion is used to at least perform processing to reduce the diameter of the workpiece by making the straight portion abut against the outer peripheral end surface of the workpiece, and the arc-shaped portion is used to at least perform processing to form the workpiece into the desired cross-sectional shape by making the arc-shaped portion abut against one surface and the other surface of the workpiece respectively.

16. The workpiece processing method according to claim 12 or 13, wherein: The convex grinding portion and the rectangular grinding portion having a straight cross-section parallel to the thickness direction of the grinding stone in a cross section along the rotation axis are arranged on the outer periphery of the grinding stone in the thickness direction. The rectangular cross-sectional grinding portion is used to at least perform processing such that the rectangular cross-sectional grinding portion abuts against the outer peripheral end surface of the workpiece and the grinding stone moves from the radial outer side toward the inner side of the workpiece to reduce the diameter of the workpiece, and the convex grinding portion is used to at least perform processing such that the convex grinding portion abuts against one surface and the other surface of the workpiece respectively to form the workpiece into the desired cross-sectional shape.

17. The workpiece processing method according to claim 15, wherein: In the process of forming the workpiece into the desired cross-sectional shape, grinding is performed that is more precise than the grinding in the process of reducing the diameter of the workpiece.

18. The workpiece processing method according to claim 16, wherein: In the process of forming the workpiece into the desired cross-sectional shape, grinding is performed that is more precise than the grinding in the process of reducing the diameter of the workpiece.

19. The workpiece processing method according to claim 12 or 13, wherein: In addition to the grinding stone, there is also a disc-shaped grooved grinding stone arranged obliquely with respect to the tangential direction of the outer periphery of the workpiece. After the convex grinding portion of the grindstone is brought into contact with the workpiece to grind the workpiece, the inner peripheral surface of the groove of the grooved grindstone is brought into contact with the workpiece to perform grinding more precisely than the grinding performed by the convex grinding portion.

20. A workpiece processing method for forming a disc-shaped workpiece into a desired cross-sectional shape using a grinding stone, the grinding stone being rotatable and having a disc-shaped portion on its outer periphery, the convex grinding portion having a cross-sectional shape convex toward the outer periphery in a cross section passing through the rotation axis of the grinding stone and having arc-shaped portions at at least both ends in the thickness direction. The workpiece processing method is characterized by comprising: a step of arranging the workpiece and the grindstone parallel to each other; as well as while rotating the grindstone and rotating the workpiece about a rotation axis parallel to the rotation axis of the grindstone, the grindstone is moved relative to the workpiece according to movement conditions calculated based on the curvature radius of the arc-shaped portion of the grindstone so that the contact portion between the convex grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece; In addition to the grinding stone, there is also a disc-shaped grooved grinding stone arranged obliquely with respect to the tangential direction of the outer periphery of the workpiece. After the convex grinding portion of the grindstone is brought into contact with the workpiece to grind the workpiece, the inner peripheral surface of the groove of the grooved grindstone is brought into contact with the workpiece to perform grinding more precisely than the grinding performed by the convex grinding portion. The workpiece processing method includes, before the step of arranging the workpiece and the circular plate-shaped grinding stone parallel to each other, the steps of arranging a circular plate-shaped dressing grinding stone parallel to the grinding stone, rotating the grinding stone about a rotation axis parallel to the rotation axis of the grinding stone, moving the grinding stone relative to the dressing grinding stone to form the outer shape of the dressing grinding stone, and pressing the material of the grooved grinding stone against the dressing grinding stone to transfer the outer shape of the dressing grinding stone to form or shape the grooves. In the step of transferring the outer shape of the dressing grindstone to form or shape the groove, the groove is formed into a shape predetermined so that the workpiece abutting against the inner peripheral surface of the groove is formed into the desired cross-sectional shape. In the step of forming the outer shape of the dressing grindstone, a movement condition is calculated in advance based on the curvature radius of the arc-shaped portion of the grinding stone, in which a contact portion between the convex grinding portion of the grinding stone and the dressing grindstone moves along a shape corresponding to the predetermined shape of the groove. In the step of forming the outer shape of the dressing grindstone, the dressing grindstone is moved relative to the grinding stone in accordance with the movement condition.

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