JP7462818B2 - Workpiece machining device, grinding wheel, and workpiece machining method - Google Patents

Description

The present invention relates to a workpiece processing device, a grinding wheel, and a workpiece processing method.

Conventionally, in order to chamfer the outer periphery of a disk-shaped workpiece (workpiece) such as a semiconductor wafer, a grinding wheel is pressed against the outer periphery of the workpiece to perform grinding. In order to improve the accuracy of the shape and dimensions of the chamfered portion of the workpiece, a groove (formed groove) with a shape and dimensions corresponding to the finished shape of the workpiece is formed on the outer periphery of the grinding wheel, the outer periphery of the workpiece is inserted into the groove, the workpiece is rotated, and the outer periphery of the workpiece is ground by the inner periphery of the groove. However, with this method, the grinding wheel needs to be replaced every time the shape or dimensions of the workpiece to be manufactured change, and it is not suitable for small-lot production of a wide variety of products. In addition, repeated chamfering causes the inner periphery of the groove on the outer periphery of the grinding wheel to wear or break, changing the shape and dimensions of the groove, which reduces the accuracy of the chamfering of the workpiece. Therefore, after chamfering the workpiece for a long period of time, it becomes necessary to replace or reshape the grinding wheel.

In order to replace or reshape the grinding wheel as necessary, the methods described in Patent Documents 1 and 2 involve preparing a master grinding wheel having a formed groove corresponding to the finished shape of the workpiece, and grinding the outer periphery of the grinding wheel material by abutting it against the inner periphery of the groove of the master grinding wheel to prepare a truing grinding wheel (truer), which is a mold material. Furthermore, by abutting the outer periphery of the truing wheel against the grinding wheel material to form a formed groove similar to that of the master grinding wheel, the shape of the grinding wheel to be used for chamfering of the actual workpiece can be adjusted (shaped). The truing wheel is made of a material (e.g., a GC wheel) harder than the grinding wheel for chamfering (e.g., a resin-bonded wheel), and the master grinding wheel is made of a material (e.g., a metal-bonded wheel) harder than the truing wheel. The process of shaping the grinding wheel using the truing wheel in this way is called truing.

In addition to the method of chamfering using the groove of a disk-shaped grinding wheel arranged parallel to a disk-shaped workpiece, Patent Documents 1 and 2 also suggest a method of chamfering a workpiece using a groove of a disk-shaped grinding wheel arranged at an angle to the tangent direction of the outer periphery of the disk-shaped workpiece (helical processing method). The helical chamfering method is also described in Patent Document 3. In the method described in Patent Document 3, the grinding wheel arranged at an angle to the tangent direction of the outer periphery of the workpiece has a concave groove formed on the outer periphery and has an inwardly inclined surface. Grinding is performed by abutting this inclined surface on the outer periphery of the workpiece. Patent Document 4 discloses a processing method in which grinding is performed with a disk-shaped grinding wheel arranged parallel to the disk-shaped workpiece, and then more precise grinding is performed by the helical method with a disk-shaped grinding wheel arranged at an angle to the tangent direction of the outer periphery of the disk-shaped workpiece, and a truing grinding wheel and a truing method for truing a grinding wheel for precision grinding in the helical method.

As described in Patent Documents 1 to 4, when chamfering a workpiece using a grinding wheel positioned at an angle to the tangent direction of the outer periphery of the workpiece, grinding is performed with a long contact area between the inner surface of the groove on the outer periphery of the grinding wheel and the outer periphery of the workpiece. Furthermore, by grinding while rotating the workpiece at a low speed, the surface roughness of the chamfered portion of the workpiece can be reduced. This makes it easier to carry out the finish polishing process that is performed later.

Patent Document 5 discloses a method of performing chamfering by using a grindstone with a groove on its outer periphery, the dimension of which in the thickness direction is larger than the thickness of the workpiece, and abutting the inner surface of the groove of the grindstone against the outer periphery of the workpiece. Patent Document 5 also discloses a method of performing chamfering by using a grindstone that is thicker than the workpiece, has no groove on its outer periphery, and has a convex cross-sectional shape on its outer periphery, and abutting an inclined surface that constitutes part of the convex part on the outer periphery of the grindstone against the outer periphery of the workpiece.

In the method described in Patent Document 6, a disk-shaped grinding wheel is placed perpendicular to a disk-shaped workpiece. The workpiece can rotate around a rotation axis located at the center of its planar shape. The grinding wheel can rotate around a rotation axis perpendicular to the rotation axis of the workpiece, and can move in a direction perpendicular to the rotation axis (parallel to the disk-shaped workpiece) and in a direction parallel to the rotation axis (perpendicular to the disk-shaped workpiece). With the workpiece rotated, the grinding wheel is rotated and brought close to the workpiece, and the outer periphery of the rotating grinding wheel is brought into contact with the outer periphery of the workpiece rotating in a direction perpendicular to the rotation direction of the grinding wheel while the grinding wheel is moved, thereby chamfering the workpiece. This type of processing process is called contouring.

In the method described in Patent Document 7, a cup-shaped grinding wheel is placed perpendicular to a disk-shaped workpiece, and like Patent Document 6, the cup-shaped grinding wheel is rotated and brought close to the workpiece while the workpiece is rotating. The cup-shaped grinding wheel is moved while the tip surface of the cup shape of the rotating cup-shaped grinding wheel is brought into contact with the outer periphery of the workpiece, which is rotating in a direction perpendicular to the rotation direction of the cup-shaped grinding wheel, thereby chamfering the workpiece.

Patent document 8 discloses a method of chamfering using two disk-shaped grinding wheels in the same manner as in Patent document 6, and a method of chamfering using two cup-shaped grinding wheels in the same manner as in Patent document 7.

In the method described in Patent Document 9, a large, double-structure cup-shaped first grinding wheel having an inner grinding wheel element (cup-shaped) and an outer grinding wheel element (cup-shaped) for more precise grinding than that achieved by the inner grinding wheel element, and a cup-shaped second grinding wheel are used to machine the outer periphery of the workpiece.

In the method described in Patent Document 10, in the peripheral edge diameter reduction process of the wafer, two grooveless grindstones are held at a fixed height and brought into contact with the wafer to process it, and in the contouring process, the two grooveless grindstones are moved separately to each side of the peripheral edge of the wafer, and the same radial location of the wafer peripheral edge is sandwiched from above and below to process each side simultaneously.

In the method described in Patent Document 11, a disk-shaped grinding wheel having a convex grinding portion on its outer periphery is used, the disk-shaped workpiece and the grinding wheel are arranged parallel to each other, and while rotating the grinding wheel and the workpiece, the grinding wheel is moved relative to the workpiece according to movement conditions calculated based on the radius of curvature of the arc-shaped portion of the grinding wheel so that the contact portion between the convex grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece.

JP 2005-153085 A JP 2007-165712 A Japanese Patent Application Laid-Open No. 5-152259 JP 2007-044817 A Japanese Patent Application Laid-Open No. 11-207585 JP 2000-317789 A JP 2008-034776 A JP 2014-37014 A JP 2017-154240 A JP 2008-177348 A Patent No. 7093875

As described in Patent Documents 1 to 4, it is not easy to form a groove for chamfering a workpiece with high precision on the outer periphery of a grinding wheel that is arranged at an angle to the tangent direction of the outer periphery of the workpiece. In order to form a chamfer of a desired shape on the workpiece, the inner periphery of the groove must contact the outer periphery of the workpiece at an appropriate angle and with an appropriate contact length. In a grinding wheel that is arranged at an angle to the tangent direction of the outer periphery of the workpiece, it is difficult to form a groove having an inner periphery that accurately contacts the outer periphery of the workpiece at an appropriate angle and with an appropriate contact length. In particular, when truing is performed by rotating a truing grinding wheel using a drive unit that rotates the workpiece or a drive unit that rotates a grinding wheel for grinding the workpiece, it is difficult to form a groove with high precision that allows good chamfering processing in a state inclined to the tangent direction of the outer periphery of the workpiece, and a method for easier truing is required. In addition, if the shape or dimensions of the chamfered portion of the workpiece to be manufactured change, the shape of the groove of the master grinding wheel for producing the truing grinding wheel must also be changed, which is cumbersome work.

When machining a workpiece using a grindstone that is tilted diagonally relative to the tangent direction of the workpiece's outer periphery, it is difficult to make fine corrections to approximate the desired machining shape, because the shape and dimensions of the inner periphery of the groove cannot be easily changed. Therefore, when manufacturing a wafer having an orientation flat as the workpiece, it is not possible to form the orientation flat with high precision using the groove for mainly forming the arc-shaped portion of the outer periphery of the workpiece, which is formed on a grindstone that is tilted diagonally relative to the tangent direction of the workpiece's outer periphery. For this reason, it is necessary to form the groove for forming the orientation flat separately from the groove for forming the arc-shaped portion, which makes the manufacture of the grindstone complicated and increases the machining time to use two grooves separately.

In the method described in Patent Document 5, the outer periphery of the workpiece is ground by abutting it against an inclined surface that is part of the inner periphery of the grinding wheel groove, or against an inclined surface that is part of the convex portion of the outer periphery of the grinding wheel. The outer periphery of the workpiece is ground by moving the workpiece relatively along the inclined surface of the grinding wheel, so the shape of the ground outer periphery of the workpiece corresponds to the inclined surface of the grinding wheel. Since the angle of the inclined surface of the outer periphery of the grinding wheel cannot be changed arbitrarily, it is difficult to form the chamfered portion of the workpiece into an arbitrary shape. In addition, grinding is performed while the workpiece is moved back and forth (traverse) relatively along the grinding wheel at the chamfered portions on both sides of the workpiece, the straight portion at the tip, and the curved portion between the straight portion and the chamfered portion, making the processing complicated and taking a long time.

In the method described in Patent Document 6, the disk-shaped grinding wheel is arranged perpendicular to the disk-shaped workpiece, so if a large grinding wheel is used, the grinding wheel may interfere with the mechanism for supporting and driving the workpiece (for example, the suction table or the rotation mechanism). Therefore, in order not to interfere with the stable support and smooth driving of the workpiece, a small grinding wheel is used instead of a large one. As a result, the processing efficiency is poor and the processing time is long. In addition, when chamfering the same workpiece, a small grinding wheel has a short life because the same part of the workpiece is in contact with the outer periphery of the workpiece and grinds for a long time compared to a large grinding wheel. Furthermore, the workpiece moves in a trajectory such that the contact part with the grinding wheel follows the desired cross-sectional shape, but the workpiece moves only after each part of the workpiece is sufficiently ground, so the workpiece needs to rotate at high speed for high efficiency. In this way, the workpiece is ground while rotating at high speed, and the grinding marks of the grindstone rotating in a direction perpendicular to the direction of rotation of the workpiece are formed on the outer surface of the workpiece in a shape that extends along the thickness direction of the workpiece, so the ground portion has a large surface roughness. Even if a more precise polishing process is performed after this grinding process, it is difficult to polish the workpiece because of the presence of the marks that run perpendicular to the direction of rotation of the workpiece. In particular, the inclined surface portion of the workpiece is difficult to polish in the subsequent precision polishing process, and there is a possibility that the workpiece will not be polished sufficiently and marks will remain.

In the method described in Patent Document 7, the production of the cup-shaped grinding wheel is complicated, and truing is particularly difficult. In addition, it is not easy to position and drive the cup-shaped grinding wheel so that the tip surface of the cup shape properly contacts the outer periphery of the workpiece, and the mechanism for supporting and driving the cup-shaped grinding wheel is complex.

In addition to the problems with the methods described in Patent Document 8, which are described in Patent Documents 6 and 7, the method described in Patent Document 8 has the problem that the device is complicated because two grinding wheels are driven simultaneously, and differences in size and shape are likely to occur between the two grinding wheels, making it difficult to perform stable, high-precision chamfering.

In the method described in Patent Document 9, the shape of the first grinding wheel is very complex, and the production of the first grinding wheel is cumbersome. In addition, because the workpieces are rotated about two rotation axes, the mechanisms for supporting and driving the workpieces are also complex. Thus, the processing device that implements the method described in Patent Document 9 is very complex.

In the method described in Patent Document 10, similar to the method described in Patent Document 6, grinding is performed using a disk-shaped grinding wheel arranged perpendicular to the disk-shaped workpiece. Moreover, in this method, a mechanism using a piezoelectric element is necessary to adjust the thickness direction position of the workpiece rotating at high speed, which makes the processing device complex and expensive, and since the workpiece is rotated while constantly adjusting the thickness direction position of the workpiece, the accuracy of forming the desired cross-sectional shape tends to deteriorate. In particular, it is difficult to keep the radius (R dimension) of the arc-shaped portion of the desired cross-sectional shape of the workpiece constant around the entire circumference of the disk-shaped workpiece.

In the method described in Patent Document 11, the convex grinding portion on the outer periphery of the grinding wheel approaches the workpiece while grinding the workpiece, resulting in large loads and vibrations during grinding. Furthermore, because the radial volume of the convex grinding portion is large, the weight of the grinding wheel and the moment of inertia during rotation are large, which results in large vibrations during rotation of the grinding wheel and high manufacturing costs for the grinding wheel. Furthermore, even if grinding water (coolant) is supplied to the contact area between the grinding wheel and the workpiece during grinding, the grinding water that comes into contact with the convex grinding portion is likely to splash, making it difficult to perform efficient and smooth grinding.

The present invention aims to provide a workpiece processing device, grinding wheel, and workpiece processing method that can perform chamfering of a workpiece easily, efficiently, and with high precision, has a simple mechanism for supporting and driving the workpiece and grinding wheel, and can easily shape the grinding wheel.

The present invention provides a workpiece machining device for forming a disk-shaped workpiece into a desired cross-sectional shape, the device comprising: a workpiece support mechanism for supporting the workpiece; a disk-shaped grinding wheel arranged parallel to the workpiece; and a grinding wheel support mechanism for supporting the grinding wheel, the workpiece support mechanism rotates the workpiece, the grinding wheel support mechanism rotates the grinding wheel, a rotation axis around which the workpiece is rotated by the workpiece support mechanism and a rotation axis around which the grinding wheel is rotated by the grinding wheel support mechanism are parallel to each other, the workpiece support mechanism has an adsorption member for adsorbing only one side of the workpiece, and a planar shape of the adsorption member is such that the planar shape of the adsorption member is such that the planar shape of the workpiece ... a circular suction member having a radius smaller than the radius of the workpiece, an outer peripheral portion of the circular suction member having a tapered shape with a thickness that decreases toward the outside, the grindstone having a concave grinding portion on the outer peripheral portion, a cross-sectional shape of the concave grinding portion in a cross section along the rotation axis of the grindstone being concave recessed from the outer peripheral side toward the inner peripheral side, and having arc-shaped portions at least on both ends in a thickness direction, and a grinding surface having a thickness greater than or equal to the thickness of the workpiece and a grinding surface for grinding at least one of reducing the diameter of the workpiece and smoothing a middle portion of the outer peripheral portion of the workpiece in a thickness direction. The grindstone and the workpiece are relatively movable by the grindstone support mechanism or the workpiece support mechanism so as to approach or move away from each other, and the grindstone support mechanism or the workpiece support mechanism moves the grindstone relative to the workpiece in accordance with a movement condition calculated based on a radius of curvature of the arc-shaped portion of the grindstone so that a contact portion between the concave grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece, and the arc-shaped portion of the grindstone moves the workpiece without generating a substantial gap between the chamfered portion of the desired cross-sectional shape of the workpiece and the chamfered portion of the desired cross-sectional shape of the workpiece. the radius of curvature of the arc-shaped portion of the grinding wheel is at least 10 times the thickness of the workpiece so that the arc-shaped portion located on the one side of the workpiece that is attracted by the suction member has a length, in a cross section along the rotation axis of the grinding wheel, that is greater than or equal to the length of the chamfered portion on the one side of the workpiece having the desired cross-sectional shape, and is less than the length at which the arc-shaped portion abuts against the tapered shape of the suction member when in contact with the end of the one side of the workpiece at a position where a tangent to the arc-shaped portion extends at an angle that matches the angle of the tapered shape of the suction member.

Another workpiece machining device for forming a disk-shaped workpiece into a desired cross-sectional shape of the present invention includes a workpiece support mechanism for supporting the workpiece, a disk-shaped grinding wheel arranged parallel to the workpiece, and a grinding wheel support mechanism for supporting the grinding wheel, the workpiece support mechanism rotates the workpiece, the grinding wheel support mechanism rotates the grinding wheel, a rotation axis that is the center of rotation of the workpiece by the workpiece support mechanism and a rotation axis that is the center of rotation of the grinding wheel by the grinding wheel support mechanism are parallel to each other, the workpiece support mechanism has an adsorption member that adsorbs only one side of the workpiece, the planar shape of the adsorption member is a circle with a radius smaller than the radius of the workpiece, and an outer peripheral portion of the circular adsorption member is a circular adsorption member. has a tapered shape that becomes thinner toward the outside, the grinding wheel has a concave grinding portion on its outer periphery, the cross-sectional shape of the concave grinding portion in a cross section along the rotation axis of the grinding wheel is concave recessed from the outer periphery toward the inner periphery, and has at least an arc-shaped portion at each end in the thickness direction, and a slope portion located outside the arc-shaped portion in the thickness direction and continuously connected to the arc-shaped portion, and has a straight portion between the arc-shaped portions at each end , the straight portion having a thickness equal to or greater than the thickness of the workpiece and performing grinding for at least one of reducing the diameter of the workpiece and smoothing the middle portion of the outer periphery of the workpiece in the thickness direction , and the slope portion has a shape having the desired cross-sectional shape. The concave grinding portion extends along a tangent direction of the arc-shaped portion at a boundary position between the arc-shaped portion and the inclined surface portion, which coincides with the angle of the chamfer on the one surface side of the workpiece, the grindstone and the workpiece can be relatively moved toward and away from each other by the grindstone support mechanism or the workpiece support mechanism, and the grindstone support mechanism or the workpiece support mechanism moves the grindstone relative to the workpiece in accordance with a movement condition calculated based on a radius of curvature of the arc-shaped portion of the grindstone so that a contact portion between the concave grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece, and the radius of curvature of the arc-shaped portion of the grindstone is at least 10 times the thickness of the workpiece. The above is characterized in that the inclined portion located on the one side of the workpiece that is attracted by the suction member has a length that is greater than or equal to the length of the chamfered portion on the one side of the workpiece having the desired cross-sectional shape, in a cross section along the rotation axis of the grinding wheel, and when the angle in which the inclined portion extends with respect to the one side of the workpiece is smaller than the angle that the tapered shape of the suction member makes with respect to the one side of the workpiece, the inclined portion has a length that is less than the length at which the inclined portion abuts the tapered shape of the suction member when in contact with the end of the one side of the workpiece at a position where a tangent to the arc-shaped portion extends at an angle that matches the angle of the tapered shape of the suction member.

The present invention provides a method for machining a disc-shaped workpiece into a desired cross-sectional shape using a grindstone having a concave grinding portion on its outer periphery and a circular grinding wheel that is rotatable, the concave grinding portion having a cross-sectional shape in a cross section along a rotation axis of the grindstone being concave recessed from the outer periphery toward the inner periphery, the concave grinding portion having an arc-shaped portion at least at both ends in a thickness direction, and a straight portion having a thickness equal to or greater than the thickness of the workpiece and performing grinding for at least one of reducing the diameter of the workpiece and smoothing an intermediate portion of the outer periphery in the thickness direction of the workpiece between the arc-shaped portions at both ends, the straight portion having a thickness equal to or greater than the thickness of the workpiece and performing grinding for at least one of reducing the diameter of the workpiece and smoothing an intermediate portion of the outer periphery in the thickness direction of the workpiece, the method comprising the steps of: disposing the workpiece and the grindstone parallel to each other; and rotating the grindstone and rotating the workpiece about a rotation axis parallel to the rotation axis of the grindstone, while moving the grindstone relatively to the workpiece in accordance with a moving condition calculated based on a radius of curvature of the arc-shaped portion of the grindstone so that a contact portion between the concave grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece, the grindstone being configured to move in a direction parallel to the rotation axis of the grindstone. the step of moving the grinding wheel relative to the workpiece includes: rotating the workpiece , only one side of which is attracted by the attraction member, and the grinding wheel, while moving the arc-shaped portion of the concave grinding portion of the grinding wheel in a curved manner relative to the workpiece from the outer circumferential end face of the workpiece toward one side by an angle calculated in advance in accordance with the movement conditions, thereby grinding the outer circumferential portion of the one side of the workpiece to form a chamfered portion of the desired cross-sectional shape of the workpiece ; moving the grinding wheel relative to the workpiece along the outer circumferential end face of the workpiece from the one side to the other side; and while rotating the workpiece and the grinding wheel, moving the arc-shaped portion of the concave grinding portion of the grinding wheel in a curved manner relative to the workpiece from the outer circumferential end face of the workpiece toward the other side by an angle calculated in advance in accordance with the movement conditions, thereby grinding the outer circumferential portion of the other side of the workpiece to form a chamfered portion of the desired cross -sectional shape of the workpiece, The suction member has a circular shape, and an outer peripheral portion of the circular suction member has a tapered shape that becomes thinner toward the outside, and the radius of curvature of the arc-shaped portion of the grindstone is at least 10 times the thickness of the workpiece so that the arc-shaped portion of the grindstone abuts against the workpiece without generating a substantial gap between the arc-shaped portion and the chamfered portion of the desired cross-sectional shape of the workpiece, and the arc-shaped portion located on the side of the one surface of the workpiece that is sucked by the suction member is located in front of the desired cross-sectional shape in a cross section along the rotation axis of the grindstone. the workpiece has a length equal to or longer than the length of the chamfered portion on the one surface side, and shorter than the length at which the arc-shaped portion abuts against the tapered shape of the attraction member in a state where the tangent of the arc-shaped portion abuts against the end of the one surface side of the workpiece at a position where the tangent of the arc-shaped portion extends at an angle that coincides with the angle of the tapered shape of the attraction member, and when rough grinding of the outer periphery of the one surface side or the other surface side of the workpiece is performed, the arc-shaped portion of the concave grinding portion of the grindstone is ground from the outer periphery end face of the workpiece to the one surface side or the other surface side of the workpiece while rotating the workpiece and the grindstone. or, when performing precision grinding of the outer periphery of the one face side or the other face side of the workpiece, the grinding wheel is moved in a curved manner relative to the workpiece by an angle calculated in advance in accordance with the movement conditions, from the outer periphery end face of the workpiece toward the one face side or the other face side of the workpiece, so that the rotation axis of the grinding wheel and the rotation axis of the workpiece are located in the same plane, and then the relative movement of the grinding wheel with respect to the workpiece is stopped. When performing precision grinding of the outer periphery of the one face side or the other face side of the workpiece, while rotating the workpiece and the grinding wheel, the arc-shaped portion of the concave grinding portion of the grinding wheel is moved in a curved manner relative to the workpiece by an angle calculated in advance in accordance with the movement conditions, from the outer periphery end face of the workpiece toward the one face side or the other face side, so that the rotation axis of the grinding wheel and the rotation axis of the workpiece are located in the same plane, and then the grinding wheel is moved linearly relative to the workpiece so that the rotation axis of the grinding wheel and the rotation axis of the workpiece move relatively in a plane extending in a direction perpendicular or obliquely intersecting the plane in which the rotation axis of the grinding wheel and the rotation axis of the workpiece were located during the curved movement.

A rotatable, disk-shaped grinding wheel having a concave grinding portion on its outer periphery, the cross-sectional shape of the concave grinding portion in a cross section along the rotation axis of the grinding wheel is concave recessed from the outer periphery toward the inner periphery, and has at least an arc-shaped portion at each end in the thickness direction, and a slope portion located outside the arc-shaped portion in the thickness direction and continuously connected to the arc-shaped portion, and has a thickness greater than or equal to the thickness of the workpiece between the arc-shaped portions at both ends for at least one of reducing the diameter of the workpiece and smoothing the middle portion of the outer periphery of the workpiece in the thickness direction. Another method for forming a disk-shaped workpiece into a desired cross-sectional shape using a grindstone having a shape having a straight portion for grinding the concave grinding surface includes the steps of: arranging the workpiece and the grindstone parallel to each other; rotating the grindstone and rotating the workpiece about a rotation axis parallel to the rotation axis of the grindstone; and moving the grindstone relative to the workpiece in accordance with a movement condition calculated based on a radius of curvature of the arc-shaped portion of the grindstone so that a contact portion between the concave grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece. and a step of moving the grindstone relative to the workpiece, the step including: rotating the workpiece, only one side of which is attracted by an attraction member , and the grindstone, while moving the arc-shaped portion of the concave grinding portion of the grindstone in a curved manner from the outer peripheral end face of the workpiece toward one side by an angle calculated in advance according to the movement conditions, thereby grinding the outer periphery of the one side of the workpiece to form a chamfered portion of the workpiece having the desired cross-sectional shape ; and moving the grindstone along the outer peripheral end face of the workpiece toward the one side. and, while rotating the workpiece and the grindstone, moving the arc-shaped portion of the concave grinding portion of the grindstone in a curved manner from the outer peripheral end face of the workpiece toward the other surface by an angle calculated in advance according to the movement conditions, thereby grinding the outer periphery of the other surface side of the workpiece to form a chamfered portion of the workpiece having the desired cross-sectional shape, wherein the planar shape of the attraction member is a circle with a radius smaller than the radius of the workpiece, and the outer periphery of the circular attraction member is a circle with a radius smaller than the radius of the workpiece. The peripheral portion has a tapered shape that becomes thinner toward the outside, the radius of curvature of the arc-shaped portion of the grindstone is at least 10 times the thickness of the workpiece, the inclined portion extends along a tangent direction of the arc-shaped portion at a boundary position between the arc-shaped portion and the inclined portion, which coincides with the angle of the chamfer on the one side of the workpiece having the desired cross-sectional shape, and the inclined portion located on the one side of the workpiece that is attracted by the attraction member is located at a cross section along the rotation axis of the grindstone that coincides with the angle of the chamfer on the one side of the workpiece having the desired cross-sectional shape. a chamfered portion on the one side of the workpiece, and an angle formed by a direction in which the inclined portion extends with respect to the one side of the workpiece is smaller than an angle formed by the tapered shape of the suction member with respect to the one side of the workpiece, the inclined portion has a length less than a length at which the inclined portion abuts against the tapered shape of the suction member in a state in which the tangent of the arc-shaped portion contacts the end of the one side of the workpiece at a position where the tangent of the arc-shaped portion extends at an angle that coincides with the angle of the tapered shape of the suction member, and when rough grinding of the outer periphery of the one side or the other side of the workpiece is performed, While rotating the workpiece and the grindstone, the arc-shaped portion of the concave grinding portion of the grindstone is moved in a curved manner relative to the workpiece from the outer peripheral end face of the workpiece toward the one surface or the other surface by an angle calculated in advance according to the movement conditions so that the rotation axis of the grindstone and the rotation axis of the workpiece are positioned in the same plane, and then the relative movement of the grindstone with respect to the workpiece is stopped. When performing precise grinding of the outer peripheral portion of the one surface side or the other surface side of the workpiece, the concave grinding portion of the grindstone is moved in a curved manner relative to the workpiece by an angle calculated in advance according to the movement conditions. The method is characterized in that the arc-shaped portion of the grinding portion is moved curvilinearly relative to the workpiece from the outer peripheral end face of the workpiece toward the one face or the other face by an angle calculated in advance according to the movement conditions so that the rotation axis of the grinding wheel and the rotation axis of the workpiece are located in the same plane, and then the grinding wheel is moved linearly relative to the workpiece while maintaining the state in which the rotation axis of the grinding wheel and the rotation axis of the workpiece are located in the plane in which the rotation axis of the grinding wheel and the rotation axis of the workpiece were located during the curvilinear movement.

A further method for forming a disk-shaped workpiece into a desired cross-sectional shape using a grinding wheel having a concave grinding portion on its outer periphery and a rotatable disk-shaped grinding wheel, the concave grinding portion having a cross-sectional shape in a cross section along the rotation axis of the grinding wheel that is concave recessed from the outer periphery toward the inner periphery, at least one of an arc-shaped portion at each end in the thickness direction, and a straight portion having a thickness equal to or greater than the thickness of the workpiece and performing grinding for at least one of reducing the diameter of the workpiece and smoothing an intermediate portion of the outer periphery of the workpiece in the thickness direction, is a method for forming a disk-shaped workpiece into a desired cross-sectional shape using a grinding wheel having a concave grinding portion on its outer periphery and a cross-sectional shape in a cross section along the rotation axis of the grinding wheel that has an arc-shaped portion at least at both ends in the thickness direction, and a straight portion between the arc-shaped portions at both ends that has a thickness equal to or greater than the thickness of the workpiece and performs grinding for at least one of reducing the diameter of the workpiece and smoothing an intermediate portion of the outer periphery of the workpiece in the thickness direction. and a step of moving the grindstone relatively to the workpiece in accordance with a movement condition calculated based on a radius of curvature of the arc-shaped portion of the grindstone so that a contact portion between the concave ground portion and the workpiece moves along the desired cross-sectional shape of the workpiece while rotating the grindstone and the workpiece about a rotation axis parallel to the rotation axis of the grindstone. The step of moving the grindstone relatively to the workpiece includes: rotating the workpiece, only one surface of which is attracted by an attraction member, and the grindstone, and moving the grindstone relatively to the workpiece in accordance with a movement condition calculated based on a radius of curvature of the arc-shaped portion of the grindstone so that a contact portion between the concave ground portion and the workpiece moves along the desired cross-sectional shape of the workpiece. a grinding wheel moving along the outer circumferential end face of the work from the one surface side to the other surface side relative to the work, the ... and grinding the outer periphery of the other surface side of the workpiece by moving the grindstone in a curved line relative to the workpiece to form a chamfered portion of the desired cross-sectional shape of the workpiece , wherein the planar shape of the attraction member is a circle having a radius smaller than the radius of the workpiece, the outer periphery of the circular attraction member has a tapered shape that becomes thinner toward the outside, the radius of curvature of the arc-shaped portion of the grindstone is at least 10 times the thickness of the workpiece so that the arc-shaped portion of the grindstone abuts against the workpiece without generating a substantial gap between the arc-shaped portion of the grindstone and the chamfered portion of the desired cross-sectional shape of the workpiece, and the arc-shaped portion located on the one surface side that is attracted by the attracting member has a length, in a cross section along the rotation axis of the grindstone, that is equal to or longer than the length of the chamfered portion on the one surface side of the workpiece having the desired cross-sectional shape, and is shorter than a length that abuts against the tapered shape of the attracting member in a state where the tangent of the arc-shaped portion abuts against the end of the one surface side of the workpiece at a position that extends at an angle that coincides with the angle of the tapered shape of the attracting member, and when rough grinding of the outer periphery of the one surface side or the other surface side of the workpiece is performed, the workpiece and the grindstone are rotated, and the front of the concave grinding portion of the grindstone is ground. When the arc-shaped portion is moved in a curved manner relative to the workpiece from the outer peripheral end surface of the workpiece toward the one surface or the other surface by an angle calculated in advance according to the movement conditions, the relative movement of the grindstone with respect to the workpiece is stopped, and when performing precise grinding of the outer periphery of the one surface side of the workpiece, the arc-shaped portion of the concave grinding portion of the grindstone is moved from the outer peripheral end surface of the workpiece toward the one surface, while rotating the workpiece and the grindstone, taking into account a position error in the thickness direction that occurs when the workpiece rotates, and using as a reference the outermost position on the one surface side in the thickness direction through which the workpiece passes when it rotates. After the grinding wheel is moved in a curved line relative to the workpiece by an angle calculated in advance according to the movement conditions, the movement is stopped, and the workpiece is rotated at least one revolution while adjusting the position in the thickness direction of the workpiece at a position where the grinding wheel contacts the slope of the chamfered portion on the one side of the workpiece, thereby grinding the one side of the workpiece while canceling out a position error during rotation of the workpiece, and when performing precise grinding of the outer periphery of the other side of the workpiece, the workpiece and the grinding wheel are rotated while taking into account a position error in the thickness direction that occurs during rotation of the workpiece. the arc-shaped portion of the concave grinding portion of the grinding wheel is moved in a curved manner relative to the workpiece from the outer peripheral end face of the workpiece toward the other surface by an angle calculated in advance in accordance with the movement conditions, based on the outermost position on the other surface side in the thickness direction through which the grinding wheel passes, and then the movement is stopped; and at a position where the grinding wheel contacts the sloping surface of the chamfered portion on the other surface side of the workpiece, the rotation speed of the workpiece is slowed down and the workpiece is rotated at least one revolution while adjusting the position in the thickness direction of the workpiece, thereby grinding the other surface side of the workpiece while canceling out a position error during rotation of the workpiece.

The present invention provides a workpiece processing device, grinding wheel, and workpiece processing method that can perform chamfering of a workpiece easily, efficiently, and with high precision, has a simple mechanism for supporting and driving the workpiece and grinding wheel, and can easily shape the grinding wheel.

1 is a front view showing a schematic view of a workpiece machining device according to a first embodiment of the present invention; FIG. 2 is a cross-sectional view showing a grindstone of the workpiece machining apparatus shown in FIG. 1A to 1C are front views sequentially and diagrammatically illustrating an example of a workpiece machining method according to a first embodiment of the present invention. FIG. 4 is an enlarged view showing the step shown in FIG. 5 is an enlarged view showing a step subsequent to the step shown in FIG. 4; FIG. 6 is an enlarged view showing a step subsequent to the step shown in FIG. 5 . (A) is a front view showing an example of a workpiece machined in the first embodiment of the present invention, (B) is an explanatory diagram for explaining the magnitude of positional deviation in the thickness direction and horizontal direction of the upper surface side of the workpiece, and (C) is an explanatory diagram for explaining the magnitude of positional deviation in the thickness direction and horizontal direction of the lower surface side of the workpiece. FIG. 4 is a front view showing another example of the workpiece machined in the first embodiment of the present invention. FIG. 1 is a cross-sectional view showing an example of a grindstone of a conventional workpiece processing device. 2 is a cross-sectional view showing in detail an example of a grindstone and a grindstone support mechanism of the workpiece machining apparatus shown in FIG. 1 . FIG. 2 is an explanatory diagram for explaining preferred dimensions of the grindstone according to the first embodiment of the present invention. FIG. 6 is a cross-sectional view showing a grindstone of a workpiece machining apparatus according to a second embodiment of the present invention. FIG. 11 is an explanatory diagram for explaining preferred dimensions of a grinding wheel according to a second embodiment of the present invention. FIG. 11 is a front view illustrating a workpiece machining device according to a third embodiment of the present invention. FIG. 10 is a front view showing a workpiece machining device according to a fourth embodiment of the present invention. 1 is a plan view of a workpiece and a grinding wheel for explaining an example of a workpiece machining method of the present invention. FIG. 10 is a plan view of a workpiece for explaining another example of the workpiece machining method of the present invention. FIG. 18 is an explanatory diagram for explaining an example of a workpiece machining method described with reference to FIG. 17 .

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a front view showing a workpiece processing device 1 according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a grinding wheel 5 of the workpiece processing device 1. The workpiece processing device 1 is a device that grinds a disk-shaped workpiece 2 such as a semiconductor wafer, a glass substrate, or a ceramic, and chamfers the outer periphery of the workpiece 2. The workpiece processing device 1 is particularly suitable for chamfering a high-hardness workpiece 2 including silicon (Si), silicon carbide (SiC), gallium nitride (GaN), gallium arsenide (GaAs), sapphire, etc. However, the workpiece processing device 1 can also be used to process other types of workpieces.

The workpiece processing device 1 has a workpiece support mechanism 4 that supports a disk-shaped workpiece 2 and rotates it around a rotation axis 3, and a grinding wheel support mechanism 7 that supports a disk-shaped grinding wheel 5 and rotates it around a rotation axis 6. As an example, the workpiece 2 is disk-shaped with a diameter of 50 to 300 mm and a thickness of about 1 mm or less, and the grinding wheel 5 is disk-shaped with a diameter of 100 to 200 mm and a thickness of about 20 to 60 mm. For convenience, the thickness of the workpiece 2 is illustrated as being thick in the drawings. The workpiece support mechanism 4 and the grinding wheel support mechanism 7 support the disk-shaped workpiece 2 and the disk-shaped grinding wheel 5 in parallel with each other. The workpiece support mechanism 4 adsorbs and holds one side 2b of the disk-shaped workpiece 2 with an adsorption member 10, and can rotate the workpiece 2 around a rotation axis 3 that is located at the center of the planar shape of the workpiece 2 and perpendicular to the workpiece 2. Similarly, the grindstone support mechanism 7 can rotate the disk-shaped grindstone 5 around a rotation axis 6 that is located at the center of the planar shape of the grindstone 5 and perpendicular to the grindstone 5. The rotation axis 3, which is the center of rotation of the workpiece 2 by the workpiece support mechanism 4, and the rotation axis 6, which is 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 relatively to each other by the grindstone support mechanism 7 or the workpiece support mechanism 4 so as to approach or move away from each other. As an example, the grindstone support mechanism 7 can move the grindstone 5 in a direction in which the grindstone 5 approaches the workpiece 2 and in a direction in which the grindstone 5 moves away from the workpiece 2 in a plane parallel to the grindstone 5 and the workpiece 2 (in a plane perpendicular to the rotation axis 3 and the rotation axis 6) while rotating the grindstone 5, and can move the grindstone 5 in a direction in which the grindstone 5 approaches the workpiece 2 and in a direction in which the grindstone 5 moves away from the workpiece 2 in a plane perpendicular to the grindstone 5 and the workpiece 2 (in a plane parallel to the rotation axis 3 and the rotation axis 6). Therefore, the grinding wheel 5 can approach the workpiece 2 from any direction and move away from it in any direction within a plane including at least the rotation axes 3 and 6 by the grinding wheel support mechanism 7. The workpiece support mechanism 4 has a temperature adjustment mechanism 15 that generates a flow of liquid or gas to keep the temperature of the rotation axis 3 of the workpiece support mechanism 4 constant. Although not described in detail, the workpiece support mechanism 4 and the grinding wheel support mechanism 7 may be composed of a known suction table, a rotary motor, a movable stage, etc. Detailed and specific configuration examples of the workpiece support mechanism 4 will be described later.

2, the grinding wheel 5 of the workpiece processing device 1 has a base disk portion 5a serving as a base body, a concave grinding portion 5b located on the outer periphery of the base disk portion 5a, and a grinding portion 5g having a rectangular cross section arranged in line with the concave grinding portion 5b in the thickness direction. The base disk 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 through which the rotating shaft 6 is inserted, and a recess 5d for mounting to a holding portion (e.g., a flange portion) not shown in the figure of the grinding wheel support mechanism 7. The concave grinding portion 5b located on the outer periphery of the grinding wheel 5 is made of a metal bond grinding wheel or a resin bond grinding wheel, etc., and the cross-sectional shape of the concave grinding portion 5b in a cross section along the rotating shaft 6 of the grinding wheel 5 is a concave shape recessed from the radial outside (outer periphery side) to the inside (inner periphery side), and has arc-shaped portions 5e at both ends in the thickness direction, and has a straight portion 5f having a thickness greater than the thickness of the workpiece 2 between the arc-shaped portions 5e at both ends. The concave ground portion 5b does not include a convex portion that protrudes radially outward. The rectangular cross-sectional ground portion 5g is located further outward than the concave ground portion 5b in the thickness direction of the grinding wheel 5, and the surface facing the workpiece 2 is a straight line parallel to the thickness direction of the grinding wheel 5 in a cross section along the rotation shaft 6. In FIG. 2, the boundary between the arc-shaped portion 5e and the straight portion 5f is shown by a virtual line (two-dot chain line).

A workpiece machining method using the workpiece machining device 1 shown in FIG. 1 will be described. FIGS. 3(A) to 3(D) are front views that show an example of this workpiece machining method in sequence. As shown in FIGS. 3(A) to 3(D), the thickness of the grindstone 5 is much larger than that of the workpiece 2. First, the workpiece 2 (e.g., a semiconductor wafer) is sucked and held by the suction member 10 of the workpiece support mechanism 4 and rotated around the rotation axis 3. The workpiece 2 is rotated but does not move. The grindstone 5 attached to the grindstone support mechanism 7 is rotated around the rotation axis 6 by the grindstone support mechanism 7 and moved so that the outer periphery of the grindstone 5 abuts on the outer periphery of the workpiece 2. As an example, as shown in FIG. 3(A), the grindstone 5 attached to the grindstone support mechanism 7 is arranged so that the cross-sectional rectangular grinding portion 5g faces the workpiece 2 sucked and held by the suction member 10 of the workpiece support mechanism 4. While rotating the workpiece 2 around the rotation axis 3 and rotating the grindstone 5 around the rotation axis 6, the grinding wheel 5 is brought into contact with the outer periphery of the workpiece 2 to grind it. The grinding wheel 5 is used to roughly grind (roughly grind) the outer periphery of the workpiece 2, thereby reducing the diameter of the workpiece 2 to approach the desired size. The outer periphery of the workpiece 2 thus roughly ground by the grinding wheel 5 is brought into contact with the straight line portion 5f of the concave grinding portion 5b of the grindstone 5 as shown in FIG. 3B, thereby grinding (finely grinding) the outer periphery of the workpiece 2 to the desired size (desired diameter).

Then, while moving the grindstone 5 to one side of the workpiece 2 (above the workpiece 2 in the example shown in Fig. 3(A) to Fig. 3(D)), the workpiece 2 and the grindstone 5 are continued to rotate, and the grindstone 5 is moved relative to the workpiece 2 with the outer periphery of the grindstone 5 abutting against the outer periphery of one side of the workpiece 2 as shown in Fig. 3(C). Specifically, the grindstone 5 is gradually moved from near the center in the thickness direction of the workpiece 2 and radially inside toward the other side of the workpiece 2 (the lower side in the example shown in Fig. 3(A) to Fig. 3(D)) and radially outside . As a result, the arc-shaped portion 5e of the upper concave grinding portion 5b of the grindstone 5 abuts against the edge of one side (upper side) of the outer periphery of the workpiece 2, grinding and chamfering, and the chamfered portion 2a is formed.

When the chamfering of the upper edge of the outer periphery of the workpiece 2 is completed, the grindstone 5 is moved (raised) to one side (upward in the example shown in Fig. 3(A) to Fig. 3(D)) so that the vicinity of the center in the thickness direction of the grindstone 5 faces the workpiece 2. Then, as shown in Fig. 3(D), the circular arc portion 5e of the concave grinding portion 5b of the grindstone 5 is brought into contact with the outer periphery of the other side of the workpiece 2, and the grindstone 5 is raised while moving from the inside to the outside in the radial direction of the workpiece 2. In this way, the circular arc portion 5e of the lower concave grinding portion 5b of the rotating grindstone 5 is brought into 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 and forming the chamfered portion 2a. Finally, the workpiece 2 is positioned outside the concave grinding portion 5b of the grindstone 5, and the grindstone 5 is not in contact with the workpiece 2, and the chamfering of the workpiece 2 is completed. As shown in Fig. 3(A) to Fig. 3(D), in the thickness direction of the workpiece 2 and the grindstone 5, the grindstone 5 moves back and forth (traverses) from a position facing the center of the workpiece 2 to one side and the other side (up and down) to chamfer the upper edge and the lower edge of the outer periphery of the workpiece 2. The upper edge and the lower edge of the outer periphery of the workpiece 2 are both chamfered by the movement of the grindstone 5 in the same direction in the radial direction of the workpiece 2 (movement from the radial inside to the radial outside of the workpiece 2). In this embodiment, the chamfered portions 2a on both sides are formed by the movement of the grindstone 5 in only one direction from the radial inside to the radial outside of the workpiece 2. For example, as described in Patent Document 5, in this embodiment, grinding can be performed easily, quickly, and efficiently by grinding not only the straight portion at the tip of the workpiece but also the curved portion between the straight portion and the chamfered portion and the chamfered portion on both sides by the grindstone and the workpiece moving back and forth (traverses) relative to each other. In addition, since the concave grinding portion 5b of the grindstone 5 in this embodiment is mainly an arc-shaped curved surface, it is easy to calculate and design the curved surface shape according to the shape and dimensions of the chamfered portion 2a to be formed. Note that in some drawings, in order to make the desired cross-sectional shape of the workpiece 2 easier to understand, the shape of the chamfered portion 2a in a nearly completed state is shown even in the middle of or before the formation of the chamfered portion 2a.

This workpiece machining method will be described in more detail with reference to Figures 4 to 6. In the machining method of this embodiment, the movement conditions for the relative movement between the grindstone 5 and the workpiece 2 are calculated so that the contact portion between the concave 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 relatively moving the grindstone 5 and the workpiece 2 are calculated based on the radius of curvature of the arc-shaped portion 5e located at both ends in the thickness direction of the concave grinding portion 5b of the grindstone 5. According to the movement conditions thus calculated, 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 expressed as two-dimensional coordinates in a plane including the rotation axis 3 of the workpiece 2 and the rotation axis 6 of the grindstone 5, and 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 follows the points of each coordinate. Thus, in this embodiment, the grinding wheel 5 and the workpiece 2 are moved relative to each other under NC (numerically controlled) control, thereby grinding the workpiece 2.

Specifically, after roughly grinding (rough grinding) by abutting the cross-sectional rectangular grinding portion 5g of the grinding wheel 5 on the outer periphery of the workpiece 2, as shown in FIG. 4, the straight portion 5f of the concave grinding portion 5b of the grinding wheel 5 is abutted on the outer periphery of the workpiece 2 to perform more precise grinding (fine grinding) to reduce the diameter of the workpiece 2. The workpiece 2 is ground until the outer periphery of the workpiece 2 becomes almost straight and the diameter of the workpiece 2 becomes the desired size. Then, as shown in FIG. 5, the grinding wheel 5 is moved in the thickness direction relative to the workpiece 2 from a position P1 preset on one side (e.g., the upper side) of the workpiece 2 so that the corner of one side (e.g., the upper side) of the workpiece 2 slides relatively curvedly along the arc-shaped portion 5e of the concave grinding portion 5b of the grinding wheel 5. Based on the movement conditions calculated in advance, the grinding wheel 5 and the workpiece 2 move appropriately relative to each other in the thickness direction and radial direction, so that the grinding wheel 5 follows a desired curved trajectory relative to the workpiece 2. Then, when the angle α from the starting point P1 of the relative movement from the outside to the inside in the radial direction of the workpiece 2 reaches a position P2 at which the angle is a preset predetermined angle, the grinding wheel 5 is moved linearly relative to the workpiece 2 while keeping the relative movement amount between the grinding wheel 5 and the workpiece 2 constant. This forms a linear portion of the desired cross-sectional shape of the workpiece 2 (shown by a two-dot chain line). The angle α is an angle measured from the inner circumference side of the workpiece 2 within a plane including the rotation axis 3 of the workpiece 2 and the rotation axis 6 of the grinding wheel 5. Then, the grinding wheel 5 moves relatively to the outside of one surface in the thickness direction of the workpiece 2 and becomes out of contact with the workpiece 2, completing grinding of one surface of the workpiece 2. On the other surface of the workpiece 2, as shown in FIG. 6, the operation on one surface of the workpiece 2 shown in FIG. 5 is substantially reversed upside down, thereby grinding the other surface of the workpiece 2.

The difference in size between the grinding wheel 5 and the workpiece 2 is actually much larger than that shown in Figures 4 to 6 (for example, the radius of curvature of the arc-shaped portion 5e of the grinding wheel 5 is several tens of times the thickness of the workpiece 2), and the portion of the arc-shaped portion 5e of the grinding wheel 5 that contacts the outer circumferential surface of the workpiece 2 may be almost linear. For example, when the grinding wheel 5 moves and the movement angle α becomes a predetermined size (see Figures 5 and 6), the gap between the arc-shaped portion 5e of the grinding wheel 5 and the desired shape of the chamfered portion 2a formed on the workpiece 2 (shown by a two-dot chain line in Figures 5 and 6) is so small that it can be ignored, and the grinding wheel 5 may contact the workpiece 2 so that the entire chamfered portion 2a of the workpiece 2 can be ground into the desired shape. In that case, it is also possible to omit the process of stopping the movement of the grinding wheel 5 when the movement angle α becomes a predetermined size and then moving the grinding wheel 5 linearly relative to the workpiece 2. When performing more precise grinding, it is preferable to perform a step of moving the grindstone 5 in a curved line until the movement angle α reaches a predetermined value, and then moving the grindstone 5 linearly relative to the workpiece 2. However, when performing relatively rough grinding as a preliminary step to precise grinding, the operation may be simplified by omitting the step of moving the grindstone 5 in a curved line until the movement angle α reaches a predetermined value, and then moving the grindstone 5 linearly relative to the workpiece 2. In this embodiment, the radius of curvature of the arc-shaped portion 5e of the grindstone 5 is at least 10 times the thickness of the workpiece 2 so that the arc-shaped portion 5e of the grindstone 5 abuts against the workpiece 2 without generating a substantial gap between the arc-shaped portion 5e and the chamfered portion 2a of the workpiece 2 having the desired cross-sectional shape.

In this manner, in this embodiment, by moving the grindstone 5 and the workpiece 2 relatively according to the movement conditions calculated in advance, the contact portion between the grindstone 5 and the 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. When machining a different type of workpiece 2, the movement conditions for machining the workpiece 2 are calculated according to the desired cross-sectional shape of the new workpiece 2 to be machined. At this time, the movement conditions are calculated based on the radius of curvature of the arc-shaped portion 5e of the grindstone 5, so that workpieces 2 of various shapes can be accurately machined using the same grindstone 5.

The effect of this embodiment will be described. In the conventional processing methods described in Patent Documents 6 and 10, it is difficult to use a grinding wheel that is too large (large diameter) due to its structure, so processing must be performed with a small (small diameter) grinding wheel. As a result, the life of the grinding wheel is short, and the grinding wheel needs to be replaced or shaped frequently. However, in this embodiment, the grinding wheel 5 and the grinding wheel support mechanism 7 are unlikely to interfere with other members, specifically the workpiece support mechanism 4, so there are few structural constraints and the workpiece 2 can be processed using a large (large diameter) grinding wheel 5. Therefore, the life of the grinding wheel 5 is long, and the frequency of replacement and shaping of the grinding wheel 5 is low. In addition, in the processing methods described in Patent Documents 6 and 10, the rotation direction of the grinding wheel and the relative movement direction with respect to the workpiece are substantially the same (both are the thickness direction of the workpiece 2). Therefore, if there are large uneven parts on the outer periphery of the grinding wheel, linear marks along the rotation direction (thickness direction of the workpiece) are likely to be generated on the outer periphery of the workpiece due to the rotation of the grinding wheel. Since the grindstone rotates and moves in the same direction as the rotation direction, i.e., in a direction substantially parallel to the linear marks, relative to the workpiece, the linear marks are likely to remain without being erased. The part of the grindstone that caused the linear marks on the outer peripheral surface of the workpiece (large uneven part) moves relatively in the thickness direction of the workpiece while the position in the circumferential direction of the workpiece remains unchanged. Therefore, there is a possibility that a part of the workpiece that does not come into contact with the large uneven part and is not ground as deeply as the linear marks remains. As a result, the linear marks are likely to remain without being erased even when the grindstone moves. Note 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. Since the grindstone grinds the entire circumference of the workpiece and moves relatively in the thickness direction of the workpiece, in order to prevent the processing time of the workpiece from being too long, it is necessary to prevent the speed at which the grindstone moves in the thickness direction of the workpiece relative to the workpiece from slowing down too much. The portion of the workpiece that contacts the grinding wheel has a narrow width in the circumferential direction of the workpiece, and in order to prevent the speed at which the grinding wheel moves in the thickness direction of the workpiece relative to the workpiece from slowing down, it is necessary to increase the rotation speed of the workpiece (the speed of movement in the circumferential direction) to shorten the time required for the grinding wheel to contact the entire circumference of the workpiece and grind it. In this way, by increasing the rotation speed of the workpiece, even if the workpiece and the grinding wheel rotate in directions perpendicular to each other, the surface roughness of the workpiece after grinding becomes rough. In contrast, in this embodiment, the rotation direction of the grinding wheel 5 and the relative movement direction with respect to the workpiece 2 are substantially perpendicular to each other. The rotation direction of the grinding wheel 5 is the circumferential direction of the workpiece 2, and the relative movement direction is the thickness direction of the workpiece 2. If there are large uneven parts on the outer periphery of the grinding wheel 5, the rotation of the grinding wheel 5 will cause linear scratches along the circumferential direction on the outer periphery of the workpiece 2. Since the grinding wheel 5 moves relative to the workpiece 2 in a direction perpendicular to the rotation direction, i.e., in a direction substantially perpendicular to the linear scratches, while rotating, linear scratches are unlikely to remain. The portion of the grinding wheel 5 that has caused linear scratches on the outer peripheral surface of the workpiece 2 (large uneven portion) moves in a direction perpendicular to the linear scratches while rotating in the circumferential direction, so that the large uneven portion comes into contact with almost the entire outer peripheral surface of the workpiece 2 in sequence. Therefore, almost the entire outer peripheral surface of the workpiece 2 is ground by the large uneven portion to the same depth as the linear scratches. In this way, the rotation direction of the grinding wheel 5 and the relative movement direction with respect to the workpiece 2 are substantially perpendicular to each other, so that the linear scratches on the outer peripheral surface of the workpiece 2 are easily erased and smoothed. In addition, in this configuration, even if the rotation speed of the workpiece 2 is fast, the rotation direction of the grinding wheel 5 (circumferential direction of the workpiece 2) and the relative movement direction of the grinding wheel 5 (thickness direction of the workpiece 2) are perpendicular to each other, and the relative movement distance is short, so even if the grinding wheel 5 moves very slowly in the thickness direction of the workpiece 2, the processing time does not become so long. Therefore, by making the relative movement speed of the grinding wheel 5 in the thickness direction of the workpiece 2 relatively slow and grinding the entire circumference of the workpiece 2 sufficiently, the surface roughness of the workpiece after grinding can be improved.

In the conventional processing method described in Patent Document 5, grinding is performed by moving the workpiece relatively along the outer shape of the grinding wheel, so the shape of the workpiece after processing is determined by the outer shape of the grinding wheel (especially the shape and angle of the curved or linear inclined surface of the grinding wheel). Therefore, in order to form a workpiece of a different shape, it is necessary to replace the grinding wheel. In contrast, in this embodiment, the relative movement of the grinding wheel 5 and the workpiece 2 is not performed along the outer shape of the grinding wheel 5, but is performed according to movement conditions calculated taking into account the radius of curvature of the arc-shaped portion 5e of the concave grinding portion 5b of the grinding wheel 5. Therefore, when forming a workpiece 2 of a different shape, it is not necessary to replace the grinding wheel 5, and it is sufficient to change the movement conditions. In other words, it is possible to form workpieces of various shapes using the same grinding wheel 5 without replacing the grinding wheel 5. The movement conditions are calculated by calculation based on the radius of curvature of the arc-shaped portion 5e of the concave grinding portion 5b of the grinding wheel 5, and the relative movement of the grinding wheel 5 and the workpiece 2 is numerically controlled based on these movement conditions, so that the processing accuracy is good. In this way, this embodiment has many excellent effects, such as being able to form workpieces 2 of various shapes using the same grinding wheel 5, having good machining accuracy, and having a long life for the grinding wheel 5.

According to the processing device and processing method of this embodiment, as shown in Fig. 7 (A), a so-called T-shaped workpiece 2 whose outer periphery is formed by a pair of arc-shaped parts and a straight part connecting them, as shown in Fig. 8, can be formed with high accuracy. In the case of the T-shaped workpiece 2 shown in Fig. 7 (A), processing is performed according to the movement conditions obtained by calculation based on the respective radii of curvature R1, R2 of the pair of arc-shaped parts of the outer periphery, the lengths Y1, Y2 of the linear inclined surface parts connected to the respective arc-shaped parts, the angles θ1, θ2 of these inclined surface parts with respect to the surface of the workpiece 2, the length C0 of the straight part between the pair of arc-shaped parts, and the radius of curvature of the arc-shaped part 5e of the concave grinding part 5b of the grinding wheel 5 not shown in Fig. 7 (A). In the case of the R-shaped workpiece 2 shown in Figure 8, machining is performed according to movement conditions calculated based on the radius R of the semicircular portion of the outer periphery, the lengths Y1, Y2 of the linear inclined surface portions connected to both sides of the semicircular portion, the angles θ1, θ2 of these inclined surface portions relative to the surface of the workpiece 2, and the radius of curvature of the arc-shaped portion 5e of the concave grinding portion 5b of the grinding wheel 5, not shown in Figure 8. In this way, both the T-shaped workpiece 2 shown in Figure 7 (A) and the R-shaped workpiece 2 shown in Figure 8 can be machined with high precision by numerical control according to movement conditions calculated based on the dimensions of each part of the desired cross-sectional shape shown in the figure and the radius of curvature of the arc-shaped portion 5e of the concave grinding portion 5b of the grinding wheel 5.

In this embodiment, the grindstone support mechanism 7 adjusts the position of the grindstone 5 before the start of chamfering in the radial direction of the workpiece 2, i.e., the position where the grindstone 5 starts to contact the workpiece 2, and the position of the grindstone 5 at the end of the chamfering, i.e., the position where the contact of the grindstone 5 with the workpiece 2 ends, thereby adjusting the size of the chamfered portion 2a. In addition, taking into consideration the size of the chamfered portion 2a adjusted in this way and the speed at which the workpiece 2 is ground by the grindstone 5, the grindstone support mechanism 7 adjusts the speed at which the grindstone 5 is raised or lowered and the speed at which the grindstone 5 is moved in the radial direction of the workpiece 2, thereby adjusting the angle, shape, etc. of the chamfered portion 2a of the workpiece 2. Furthermore, since the contact angle of the grindstone 5 with the workpiece 2 changes depending on which part of the curved portion of the outer periphery of the grindstone 5 is brought into contact with the workpiece for grinding, the angle, shape, etc. of the chamfered portion 2a of the workpiece 2 can be adjusted. In this way, the desired shape and dimensions of the chamfered portion 2a of the workpiece 2 can be realized mainly by controlling the movement of the grindstone 5 by the grindstone support mechanism 7. For this reason, it is preferable that the grindstone support mechanism 7 drives the grindstone 5 using numerical control (NC control).

The grinding wheel 5 of this embodiment has a concave grinding portion 5b, and the grinding such as chamfering of the workpiece 2 is performed by this concave grinding portion 5b, so that stable and smooth grinding is possible, and the grinding wheel 5 can be reduced in cost and extended in life. For example, as in the configuration described in Patent Document 11 (not shown), when the grinding wheel has a convex grinding portion and grinds the workpiece such as chamfering by this convex grinding portion, grinding is performed while the center (rotation axis) of the grinding wheel and the center (rotation axis) of the workpiece are moved relatively to approach each other while the convex grinding portion is in contact with the workpiece. Since this is a relative movement in the direction in which the grinding wheel and the workpiece collide with each other, the impact and vibration during grinding are large, and the load applied to the grinding wheel and the workpiece is large. In addition, a grinding wheel having a convex grinding portion is relatively heavy and has a large moment of inertia. In contrast, the grinding wheel 5 of this embodiment has a concave grinding portion 5b, and grinding is performed while the center of the grinding wheel 5 (rotation axis 6) and the center of the workpiece 2 (rotation axis 3) are moved relatively in a direction away from each other while the concave grinding portion 5b is in contact with the workpiece 2. This reduces the impact and vibration during grinding compared to the relative movement in the direction in which the grinding wheel 5 and the workpiece 2 collide, reduces the load applied to the grinding wheel 5 and the workpiece 2, and results in a clean ground surface. In addition, compared to the convex grinding portion, the concave grinding portion 5b, which has a portion that is actually used for grinding and has the same size, can be made smaller and lighter, and the moment of inertia can also be reduced. This also contributes to reducing vibration during grinding. In this configuration in which grinding, such as chamfering, of the workpiece 2 is performed by the concave grinding portion 5b of the grinding wheel 5, the vibration and load are small, so deterioration is slow and the life is extended. This also leads to a reduction in the manufacturing cost of the grinding wheel 5.

For example, when grinding the chamfer of a workpiece using the convex grinding portion of a grinding wheel as in the configuration described in Patent Document 11 , the contact portion between the convex grinding portion and the workpiece is substantially point contact. However, when grinding the chamfer of a workpiece 2 using the concave grinding portion 5b of the grinding wheel 5 as in this embodiment, the contact portion between the concave grinding portion 5b and the workpiece 2 is surface contact, which allows efficient and stable grinding and produces a clean ground surface.

In addition, when the grinding wheel has a convex grinding portion and the workpiece is ground by this convex grinding portion, even if grinding water (coolant) is supplied to the contact portion between the grinding wheel and the workpiece in order to perform grinding smoothly, the grinding water is difficult to be retained in the contact portion between the grinding wheel and the workpiece . Therefore, it is not easy to perform efficient and smooth grinding, and a large amount of grinding water is required. In contrast, in this embodiment, the grinding wheel 5 has a concave grinding portion 5b, and when the workpiece 2 is ground by this concave grinding portion 5b, the grinding water supplied to the contact portion between the grinding wheel 5 and the workpiece 2 is retained inside the concave grinding portion 5b at the contact portion between the grinding wheel 5 and the workpiece 2. Therefore, efficient and smooth grinding can be easily performed, the amount of grinding water required is small, and grinding can be performed smoothly without clogging, excessive friction, or heat generation.

In this way, the grinding wheel 5 of this embodiment has a number of advantages by having a concave grinding portion 5b rather than a convex grinding portion. Conventionally, grinding wheels having a concave grinding portion have been used, but the conventional concave grinding portion has a groove, so-called formed groove 16a, that has a shape complementary to the shape of the desired workpiece after grinding, as shown in FIG. 9. In the case of a machining method using a grinding wheel 16 having a conventional formed groove 16a, there is a high possibility that wear and damage will occur in a specific part of the grinding wheel 16, for example, part P3 on the inner surface of the formed groove 16a where the workpiece 2 first abuts. When machining a large number of workpieces 2, wear and damage will occur in this part P3, changing the shape of the formed groove 16a, and the machining accuracy will be reduced if the grinding wheel 16 is used to machine the workpiece 2. In that case, it is necessary to replace or reshape the grinding wheel 16. In contrast, in this embodiment, the grinding wheel 5 has a concave grinding portion 5b that is much larger than the workpiece 2, and various parts of the concave grinding portion 5b of the grinding wheel 5 come into contact with the workpiece 2 to grind it, so that only certain parts are not particularly prone to wear or damage. Therefore, the life of the grinding wheel 5 is relatively long. Furthermore, in this embodiment, a grinding portion 5g having a rectangular cross section is provided in addition to the concave grinding portion 5b, and this grinding portion 5g having a rectangular cross section is used to perform rough grinding to bring the size of the workpiece 2 closer to the desired size. This prevents excessive wear and damage to the straight portion 5f of the concave grinding portion 5b, and extends the life of the grinding wheel 5. However, the rectangular cross section grinding portion 5g is not an essential component of the present invention, and it is also possible to configure the grinding to make the workpiece 2 have a desired diameter to be performed only by the straight portion 5f of the concave grinding portion 5b.

In the above-described embodiment, the grindstone support mechanism 7 moves the grindstone 5 while rotating it, and the work support mechanism 4 rotates but does not move the workpiece 2, but the present invention is not limited to such a configuration. In other words, the grindstone support mechanism 7 can only rotate the grindstone 5 without moving it, and the work support mechanism 4 can rotate the workpiece 2 and move it by numerical control. In that case, the work support mechanism 4 can move the workpiece 2 in a direction in which the workpiece 2 approaches the grindstone 5 and in a direction in which the workpiece 2 moves away from the grindstone 5 in a plane parallel to the grindstone 5 and the workpiece 2 (in a plane perpendicular to the rotation axis 3 and the rotation axis 6), and can move the workpiece 2 in a direction in which the workpiece 2 approaches the grindstone 5 and in a direction in which the workpiece 2 moves away from the grindstone 5 in a plane perpendicular to the grindstone 5 and the workpiece 2 (in a plane parallel to the rotation axis 3 and the rotation axis 6). Therefore, the grindstone support mechanism 7 allows the workpiece 2 to approach the grindstone 5 from any direction and move away from it in any direction within a plane including at least the rotation axes 3 and 6. Even with this configuration, the workpiece 2 and the grindstone 5 can be moved relative to each other so that they are in the same positional relationship as in each step shown in Figures 3 to 6, and processing can be performed in the same manner as in the processing method shown in Figures 3 to 6.

In this embodiment, the grinding wheel 5 and the workpiece 2 are rotated in the same or opposite directions rather than perpendicular to each other, so that the rotation of the grinding wheel 5 and the rotation of the workpiece 2 produce a synergistic effect, and the rotation speed of the grinding wheel 5 itself does not need to be very high. Therefore, the grinding wheel support mechanism 7 does not need to be capable of high-speed rotation, which simplifies the structure and reduces costs. In addition, because grinding is performed while rotating the workpiece 2 parallel to the grinding wheel 5, the surface roughness of the chamfered portion of the workpiece 2 can be reduced.

According to this embodiment, the grindstone 5 is arranged parallel to the workpiece 2, so that the grindstone 5 can be made large without interfering with the workpiece support mechanism 4. As a result, the outer periphery of the workpiece 2 can be formed into any cross-sectional shape using a large grindstone 5 without complicating the configuration of the workpiece processing device 1 including the grindstone support mechanism 7. In addition, by using a large grindstone 5, the processing efficiency can be improved and the processing time can be shortened, and since a wide range of the outer periphery of the grindstone 5 can be used for processing, the life of the grindstone 5 is extended. Furthermore, when processing is performed using a grindstone 16 in which a groove 16a (formed groove) having a shape corresponding to the shape of the completed workpiece 2 is formed, the inner periphery of the groove 16a (particularly the portion of the inclined surface P3 ) that abuts against the edge of the workpiece 2 before chamfering is likely to wear or break, but in this embodiment, since the grindstone 5 is not configured so that only one specific point thereof continues to abut against the edge of the workpiece 2 before chamfering, the grindstone 5 is less likely to be broken and has a long life.

When the workpiece 2 is inserted into the formed groove 16a provided in the grinding wheel 16 for machining, a chamfered portion of a specific shape and size can be formed, but in order to form a chamfered portion of a different shape and size, it is necessary to replace the grinding wheel 16 with one having a different groove 16a . However, according to this embodiment, the grinding wheel 5 having the concave grinding portion 5b is moved relative to the workpiece 2 to perform chamfering, so that the shape and size of the chamfered portion 2a to be formed can be changed by changing the path of movement of the grinding wheel 5 by numerical control. In other words, chamfered portions 2a of various shapes and sizes can be formed by a single grinding wheel 5.

A detailed configuration example of the grinding wheel 5 and grinding wheel support mechanism 7 shown in Figs. 1 and 2 is shown in Fig. 10. The grinding wheel 5 of this modified example has, for example, a base disk portion 5a made of metal, a concave grinding portion 5b made of a resin-bonded grinding wheel located on the outer periphery of the base disk portion 5a, and a grinding portion 5g having a rectangular cross section arranged in line with the concave grinding portion 5b in the thickness direction. The base disk portion 5a is made of an alloy such as aluminum or stainless steel, and has a mounting hole 5c through which the rotating shaft 6 is inserted and a recess 5d. The concave grinding portion 5b is concave from the outer periphery to the inner periphery, and has arc-shaped portions 5e at both ends in the thickness direction and a straight portion 5f located between the arc-shaped portions 5e and having a thickness greater than the thickness of the workpiece 2. The rectangular cross-sectional grinding portion 5g is located further outboard than the concave grinding portion 5b in the thickness direction of the grinding wheel 5, and the surface facing the workpiece 2 is straight and parallel to the thickness direction of the grinding wheel 5.

The grindstone support mechanism 7 shown in FIG. 10 has a case 7a, a rotary bearing portion 7b, a spindle 7c, a flange portion 7d, and a bolt 7e. The spindle 7c is rotatably supported by the rotary bearing portion 7b arranged in the case 7a. The flange portion 7d is attached to the tip of the spindle 7c protruding outside the case 7a, and the flange portion 7d is fixed to the spindle 7c by the bolt 7e. The case 7a is inserted into the recess 5d of the grindstone 5, and the mounting hole 5c of the grindstone 5 is fixed to the flange portion 7d. When the spindle 7c is rotated by a driving means (not shown), the flange portion 7d and the grindstone 5 rotate integrally with the spindle 7c. That is, the spindle 7c becomes the rotation axis 6 of the grindstone support mechanism 7. The grindstone 5 is supported so that the center of gravity of the grindstone 5 is located between the flange portion 7d, which is the mounting position where the grindstone 5 is attached, and the rotary bearing portion 7b that supports the spindle 7c. In this way, since the center of gravity of the grindstone 5 is located between the attachment position of the grindstone 5 (flange portion 7d) and the rotation bearing portion 7b, the support and rotation of the grindstone 5 are stabilized.

In this embodiment, a two-stage grinding process is performed: grinding to reduce the radius of the workpiece 2, and grinding to chamfer both sides of the outer periphery of the workpiece 2 to form the workpiece 2 into a 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 terms, and precision grinding is grinding that has better shape and dimensional accuracy and less surface roughness than rough grinding. In this embodiment, the grinding wheel 5 is provided on the outer periphery of the base disk portion 5a with a concave grinding portion (precision grinding portion) 5b that is mainly used for grinding to form the workpiece 2 into a desired cross-sectional shape, and a cross-sectional rectangular grinding portion (coarse grinding portion) 5g that is mainly used for grinding to reduce the radius of the workpiece 2.

In this embodiment, the unmachined workpiece 2 is set on the workpiece support mechanism 4 and rotated, and the grindstone 5 attached to the grindstone support mechanism 7 is rotated around the rotation axis 6 (spindle 7c) while the cross-sectionally rectangular grinding portion 5g is abutted against the outer periphery of the workpiece 2 as shown in FIG. 3(A). This roughly grinds the outer periphery of the workpiece 2 to make the outer diameter of the workpiece 2 the desired size. Next, as shown in FIG. 3(B), the straight line portion 5f of the concave grinding portion 5b of the grindstone 5 is abutted against the outer periphery of the workpiece 2 to precisely grind the outer periphery of the workpiece 2, and the middle portion in the thickness direction of the outer periphery of the workpiece 2 is smoothed. Then, as shown in FIGS. 3(C) to 3(D), the arc-shaped portion 5e of the concave grinding portion 5b of the grindstone 5 is abutted against the outer periphery of the workpiece 2 to chamfer the edges of both sides of the workpiece 2, and the workpiece 2 is formed into the desired cross-sectional shape. In this embodiment, the grinding portion 5g having a rectangular cross section is a portion where the grinding stone has a coarse grain size, and the grinding portion 5b having a concave shape is a portion where the grinding stone has a fine grain size, and where more precise grinding is performed than the grinding performed by the grinding portion 5g having a rectangular cross section to reduce the radius of the workpiece 2. In addition to the above-mentioned effects, this embodiment has the effect that when chamfering is performed by a two-stage grinding process, both steps can be easily performed using only a single grinding stone 5, and the manufacturing process is simple and low cost.

In general, when chamfering a workpiece 2 such as a semiconductor wafer, the outer peripheral surface of the workpiece 2 is ground with a grindstone to reduce the radius, and unnecessary parts of the workpiece 2 are removed to a desired size while arranging the outer shape and centering. Then, a chamfered portion 2a is formed on the workpiece 2 with a grindstone. If these grinding operations are performed with one concave grinding portion, the grinding (rough grinding) for reducing the radius of the workpiece 2 in the previous stage is mainly performed by abutting the concave grinding portion of the grindstone near the center in the thickness direction against the workpiece 2. The grinding (precise grinding) for forming the chamfered portion 2a in the later stage is performed by abutting the arc-shaped portions at both ends in the thickness direction of the concave grinding portion against the workpiece 2. Usually, the grinding for reducing the radius of the workpiece 2 has a larger grinding amount (grinding volume) than the grinding for forming the chamfered portion 2a. Therefore, the part of the concave ground part near the center in the thickness direction is worn more severely than the arc-shaped parts at both ends in the thickness direction, and the overall shape of the concave ground part is distorted. As a result, the machining accuracy of the workpiece 2 may be reduced. In contrast, in this embodiment, grinding to reduce the radius of the workpiece 2 is mainly performed by the cross-sectionally rectangular ground part 5g, grinding to smooth the outer peripheral surface of the workpiece 2 whose radius has been reduced is performed by the straight line part 5f of the concave ground part 5b, and grinding to form the chamfered part 2a of the workpiece 2 can be performed by the arc-shaped part 5e of the concave ground part 5b. In other words, grinding to reduce the radius of the workpiece 2, grinding to smooth the outer peripheral surface of the workpiece 2, and grinding to form the chamfered part 2a can be performed by different parts of the grinding wheel 5. The shape and dimensions of the cross-sectionally rectangular ground portion 5g and the straight portion 5f and the arcuate portion 5e of the concave ground portion 5b can be managed independently, and even if the wear amount of each is different, good processing can be performed by appropriately adjusting the processing conditions. The arcuate portion 5e of the concave ground portion 5b is mainly used only for grinding to form the chamfered portion 2a, and wears relatively evenly without a significant wear in only one portion (for example, a portion near the center in the thickness direction) compared to other portions. Therefore, the shape of the concave ground portion 5b of the grindstone does not change significantly, and the deterioration of the processing accuracy of the workpiece 2 can be suppressed. Although the cross-sectionally rectangular ground portion 5g wears significantly, the surface facing the workpiece 2 is a straight line parallel to the thickness direction of the grindstone 5 and has a simple shape, so that even if it wears, the processing accuracy does not decrease significantly.

Although not shown, the tapered portion of the spindle 7c that constitutes the rotating shaft 6 can be inserted into the tapered mounting hole 5c provided in the grinding wheel 5 without using a flange portion, and a fixing member such as a nut can be attached to the tip of the spindle 7c protruding from the base disk portion 5a, thereby fixing the grinding wheel 5 to the spindle 7c that constitutes the rotating shaft 6 and supporting it rotatably together with the spindle 7c. In this way, in the grinding wheel support mechanism 7 of this embodiment, the flange portion can be omitted, and the grinding wheel 5 can be stably fixed to the spindle 7c that constitutes the rotating shaft 6, and eccentricity of the grinding wheel 5 with respect to the rotating shaft 6 (spindle 7c) can be suppressed.

As shown in Figures 1 and 3, the work support mechanism 4 of this embodiment has an attraction member 10 that attracts only one side surface (e.g., the lower surface in the vertical direction) 2b of the work 2. Therefore, as shown in Figures 3(B), 3(C), and 3(D), when grinding for chamfering the work 2 with the arc-shaped portion 5e of the concave grinding portion 5b of the grinding wheel 5, the attraction member 10 must be prevented from abutting against the arc-shaped portion 5e. The planar shape of the attraction member 10 is a circle with a radius smaller than the radius of the work 2, and the outer peripheral portion of the circular attraction member 10 has a tapered shape 10a whose thickness becomes thinner toward the outside. When the radius r1 of the attraction member 10 is expressed by the radius r2 of the desired cross-sectional shape of the work 2 and the thickness t of the work 2, it is preferable that r2-10t≦r1≦r2-5t. The angle θ1 of the tapered shape 10a of the suction member 10 is preferably θ2-10≦θ1≦θ2+5 when expressed by the angle θ2 of the chamfered portion 2a of the desired cross-sectional shape of the workpiece 2. The length of the arc-shaped portion 5e located on the side of the surface (e.g., the vertical lower surface) 2b of the workpiece 2 to be sucked by the suction member 10 is less than the length at which the tangent of the arc-shaped portion 5e abuts against the tapered shape 10a of the suction member 10 in a cross section along the rotation axis 6 of the grindstone 5 when the tangent of the arc-shaped portion 5e abuts against the end of the surface (e.g., the vertical lower surface) 2b of the workpiece 2 at a position (point A in FIG. 11) that extends at an angle θ3 that coincides with the angle θ3 of the tapered shape 10a of the suction member 10. In the state shown in FIG. 11, the tangent of the arc-shaped portion 5e at point A is inclined by θ3 from the horizontal direction and is parallel to the lower surface of the tapered shape 10a of the suction member 10. In this state, if the arc-shaped portion 5e extends to point D where the lower surface of the tapered shape 10a of the attraction member 10 abuts against the arc-shaped portion 5e, the grinding process cannot be performed any further. Therefore, the length of the arc-shaped portion 5e is less than the length to point D. The inclination angle of the tangent at point D from the horizontal direction is θ4, and the radius of curvature of the arc-shaped portion 5e is r. In FIG. 11, angles θ3 and θ4 are shown as angles that the radii passing through points A and D of the arc-shaped portion 5e (radii perpendicular to the tangent at each point) make with the vertical direction. Here, the angle θ3 is known as the dimension of the tapered shape 10a of the attraction member 10. Therefore, the relationship between the radius of curvature r of the arc-shaped portion 5e of the grinding wheel 5 and the angle θ4 indicating the limit point of the length of the arc-shaped portion 5e is expressed as follows. In addition, when a straight line is drawn that is parallel to the tangent at point A of the arc-shaped portion 5e, i.e., perpendicular to the radius that passes through point A and passes through point D, the distance from that straight line to point A along the radius that passes through point A is r'.
r cos(θ3-θ4) = r-r'
θ3-θ4=cos ⁻¹ [(r−r′)/r]
θ4=θ3−cos ⁻¹ [(r−r′)/r]
By such calculations, it is possible to set the conditions for the arc-shaped portion 5e to have a length less than the length at which it abuts against the tapered shape 10a of the suction member 10, when the tangent to the arc-shaped portion 5e contacts the end portion on the underside of the workpiece 2 at a position where it extends at an angle θ3 that coincides with the angle θ3 of the tapered shape 10a of the suction member 10.

In the calculation for obtaining the angle θ4, the distance r' from a straight line that is parallel to the tangent at point A of the arc-shaped portion 5e (orthogonal to the radius that passes through point A) and passes through point D to point A along the radius that passes through point A is used. This distance r' can be obtained as follows. Here, the difference between the radius of the workpiece 2 having the desired cross-sectional shape and the radius of the suction member 10 is L. Then, this distance L is divided into three parts, and the length on the outer periphery side from the intersection point with the radius that passes through point A of the arc-shaped portion 5e is R2. This coincides with the radius of curvature of the lower curved portion of the desired cross-sectional shape of the workpiece 2 shown in Figures 7(A) and 8. Then, the part obtained by subtracting the length R2 from the distance L is divided into two parts with the intersection point with the straight line that is parallel to the tangent at point A of the arc-shaped portion 5e (orthogonal to the radius that passes through point A) and passes through point D as the center, and the length of the inner periphery side is x1, and the length of the outer periphery side is x2. The distance from the intersection point that separates the part of length x1 and the part of length x2 to the bottom surface of the workpiece 2 is B2. The distance from the surface of the suction member 10 that contacts the bottom surface of the workpiece 2 to the tapered shape 10a below it is defined as T. The distance from the starting point of the arc-shaped portion 5e on the bottom surface side of the desired cross-sectional shape of the workpiece 2 shown in Figures 7(A) and 8 to the bottom surface of the workpiece 2 is defined as B2.
x1 tan θ3 = T + B2
x1 = (T + B2) / tan θ3
x2 = L - R2 - x1 = L - R2 - (T + B2) / tan θ3
r' = R2 + x2 sin θ3 = R2 + [L - R2 - (T + B2) / tan θ3] sin θ3
By substituting r' thus determined into the equation for determining angle θ4 described above, angle θ4 for determining the upper limit of the length of arc-shaped portion 5e can be determined based on radius of curvature R2 and distance B2, which are the dimensions of the desired cross-sectional shape of workpiece 2 shown in Figures 7(A) and 8, distance T and angle θ3 of tapered shape 10a, which are known dimensions of attraction member 10, distance L determined from the dimensions of the desired cross-sectional shape of workpiece 2 and the known dimensions of attraction member 10, and radius of curvature r of arc-shaped portion 5e of grinding wheel 5.

7(A) and 8, the length of the arc-shaped portion 5e required to form the length A2 of the chamfered portion 2a of the workpiece 2 projected in the horizontal direction is calculated. The angle θ _max when the length of the arc-shaped portion 5e is the minimum required is expressed as follows using the angle θ2 that the chamfered portion 2a of the workpiece 2 makes with respect to the horizontal direction and the radius of curvature R2 of the curved portion.
A2 = R2 - R2 sin θ2 + r tan (θ2 - θ _max ) × cos θ2 = R2 (1 - sin θ2) + r tan (θ2 - θ _max ) × cos θ2
[A2-R2(1-sinθ2)]/rcosθ2=tan(θ2- _θmax )
θ2- _θmax = tan ^-1 {[A2-R2(1-sinθ2)]/rcosθ2}
θ _max =θ 2 - tan ^-1 {[A 2 - R 2 (1 - sin θ 2)] / r cos θ 2}
By such calculation, it is possible to set the condition for the arc-shaped portion 5e to have a length equal to or greater than the length of the chamfered portion 2a on the underside of the workpiece 2 having a desired cross-sectional shape. Angle θmax for determining the lower limit of the length of the arc-shaped portion 5e can be obtained based on the radius of curvature R2, angle θ2, and distance A2, which are the dimensions of the desired cross-sectional shape of the workpiece 2 shown in Figures 7(A) and ₈ .

The arc-shaped portion 5e of the grindstone is configured to end within the range between the angle _θmax and the angle θ4 from the vertical direction, as calculated above, so that the workpiece 2 can be accurately and satisfactorily machined into the desired cross-sectional shape. This relationship applies regardless of the magnitude relationship between the angle θ2 and the angle θ3. The above description is for determining the conditions for satisfactorily grinding the lower surface of the workpiece 2 with the grindstone 5 in a configuration in which the lower surface of the workpiece 2 is attracted by the attraction member 10, based on the dimensions of each part of the lower side of the workpiece 2 having the desired cross-sectional shape and the dimensions of each part of the lower arc-shaped portion 5e of the grindstone 5. Regarding the configuration in which the upper surface of the workpiece 2 is attracted by the attraction member 10, it is preferable to determine the conditions for satisfactorily grinding the upper surface of the workpiece 2 with the grindstone 5 in a manner substantially similar to the calculation described above, based on the dimensions of each part of the upper side, not the lower side, of the workpiece 2 having the desired cross-sectional shape, and the dimensions of each part of the upper arc-shaped portion 5e of the grindstone 5 in the lower side, not the lower side.

Next, a second embodiment of the present invention will be described. FIG. 12 is a cross-sectional view showing the grinding wheel 5 of the workpiece processing device 1 of this embodiment. The grinding wheel 5 of this embodiment has a base disk portion 5a, a concave grinding portion 5b located on the outer periphery of the base disk portion 5a, and a cross-sectionally rectangular grinding portion 5g arranged in line with the concave grinding portion 5b in the thickness direction, similar to the grinding wheel 5 of the first embodiment. The base disk portion 5a and the cross-sectionally rectangular grinding portion 5g have substantially the same configuration as the base disk portion 5a and the cross-sectionally rectangular grinding portion 5g of the first embodiment, so their description will be omitted. The cross-sectional shape of the concave grinding portion 5b in the cross section along the rotation axis 6 of the grinding wheel 5 is a concave shape recessed from the radially outer side (outer periphery side) to the inner side (inner periphery side), and has at least an arc-shaped portion 5e at each end in the thickness direction and a slope portion 5h located outside the arc-shaped portion 5e in the thickness direction and continuously connected to the arc-shaped portion 5e. Between the arc-shaped portions 5e at both ends, there is a straight portion 5f having a thickness equal to or greater than that of the workpiece 2. At point B, where the angle at which the tangent of the arc-shaped portion 5e inclines relative to the horizontal direction coincides with the angle θ2 that the chamfered portion 2a of the workpiece 2 having the desired cross-sectional shape makes relative to the horizontal direction, the arc-shaped portion 5e transitions to a sloped portion 5h. Therefore, the sloped portion 5h extends at an angle θ2 relative to the horizontal direction.

In this embodiment, a condition is found for a surface (e.g., a vertical lower surface) of the workpiece 2 to be brought into contact with the grinding wheel 5 and ground satisfactorily when the surface is attracted by the attracting member 10. The length of the inclined surface 5h located on the surface (e.g., the vertical lower surface) of the workpiece 2 to be attracted by the attracting member 10 is less than the length at which the inclined surface 5h abuts against the tapered shape 10a of the attracting member 10 in a cross section along the rotation axis 6 of the grinding wheel 5 when the tangent of the arc-shaped portion 5e extends at an angle θ3 that coincides with the angle θ3 of the tapered shape 10a of the attracting member 10 (point A in FIG. 13). In the state shown in FIG. 13, the tangent of the arc-shaped portion 5e at point A is inclined by θ3 from the horizontal direction and is parallel to the lower surface of the tapered shape 10a of the attracting member 10. In this state, if the inclined portion 5h extends to point E where the lower surface of the tapered shape 10a of the suction member 10 abuts against the inclined portion 5h, further grinding is not possible. Therefore, the length of the inclined portion 5h is less than the length to point E. The angle that a straight line extending from the center of curvature of the arc-shaped portion 5e to point E makes with the vertical direction is defined as θ5. When a straight line is drawn that is parallel to the tangent at point A of the arc-shaped portion 5e, i.e., perpendicular to the radius that passes through point A and passes through point E, the distance from this line to point B along the radius that passes through point B is defined as x5. Also, the distance along this straight line between the radius that passes through point A and the radius that passes through point B is defined as x4.
x5 = r' - x4 tan [(θ3 - θ2) / 2]
x4 = (r - r') tan (θ3 - θ2)
x3 = r tan(θ2 - θ5) = x5 / tan(θ3 - θ2)
θ5=θ2−tan ⁻¹ [x5/r tan(θ3−θ2)]
By such calculation, it is possible to set a condition for the inclined surface portion 5h to have a length less than the length at which the inclined surface portion 5h abuts against the tapered shape 10a of the attraction member 10 in a state in which the concave ground portion 5b abuts against the end portion on the lower surface side of the workpiece 2 at a position where a tangent to the arc-shaped portion 5e extends at an angle θ3 that coincides with the angle θ3 of the tapered shape 10a of the attraction member 10. Therefore, by configuring the inclined surface portion 5h of the grinding wheel 5 to terminate within the range between the angle _θmax and the angle θ5 from the vertical direction as described above, the workpiece 2 can be accurately and satisfactorily machined into a desired cross-sectional shape.

Next, a third embodiment of the present invention will be described. FIG. 14 is a front view showing a workpiece machining apparatus of this embodiment. The workpiece machining apparatus of this embodiment has a grindstone 5 similar to the grindstone 5 of the first embodiment, but having a rectangular cross-sectional grinding portion 5g only on the upper surface side, and a disk-shaped grooved grindstone 12 arranged at an angle to the tangent direction of the outer periphery of a disk-shaped workpiece 2. The grooved grindstone 12 is supported by a grooved grindstone support mechanism 13 and can rotate around a rotation shaft 14. This workpiece machining apparatus performs chamfering by a two-stage grinding process, and the rough grinding process in the first stage is performed by implementing the above-mentioned processing method using the rectangular cross-sectional grinding portion 5g and the concave grinding portion 5b of the grindstone 5 similar to the first embodiment. Then, the precision grinding process in the latter stage is performed by the grooved grindstone 12 arranged at an angle to the tangent direction of the outer periphery of the workpiece 2. A concave groove 12a is provided on the outer periphery of the grooved grindstone 12, and by inserting the outer periphery of the workpiece 2 into this groove 12a, the inner periphery of the groove 12a is brought into contact with the outer periphery of the workpiece 2 and ground to form a chamfered portion. According to this embodiment, the effects of the helical processing method, such as low surface roughness, can be obtained, and the effect of performing rough grinding with the grindstone 5 that moves while rotating can be obtained so that the subsequent precision grinding by the helical method using the grooved grindstone 12 can be performed more efficiently in a shorter time.

The workpiece processing device of this embodiment has a truing grindstone 11 for truing the grooved grindstone 12, which can be attached to the workpiece support mechanism 4 instead of the workpiece 2 and can rotate around the rotation axis 3. The truing grindstone 11 is made of a GC grindstone or the like which is harder than the grooved grindstone 12 made of a resin bond grindstone, and has a diameter and thickness approximately equal to those of the workpiece 2. The truing grindstone 11 made of a GC grindstone or the like is processed in the same manner as the processing of the workpiece 2 using a grindstone 5 which is usually made of a metal bond grindstone, and is formed into a cross-sectional shape (a shape corresponding to the shape of the preset groove 12a) to be transferred to the inclined grooved grindstone 12. The method similar to the processing of the workpiece 2 is to calculate the movement conditions under which the contact portion between the concave grinding portion 5b of the grinding wheel 5 and the truing grinding wheel 11 moves along a shape corresponding to the shape of the groove 12a set in advance based on the radius of curvature of the arc-shaped portion 5e of the grinding wheel 5, and to form the outer shape of the truing grinding wheel 11 by moving the truing grinding wheel 11 relative to the grinding wheel 5 according to the movement conditions. The shape of the groove 12a set in advance is a shape suitable for forming the workpiece 2 that abuts on the inner peripheral surface of the groove 12a into a desired cross-sectional shape. The truing grinding wheel 11 having the cross-sectional shape formed in this way is pressed against the outer peripheral portion of the inclined grooved grinding wheel 12 before the groove is formed or shaped while rotating around the rotation axis 3, and the outer shape of the truing grinding wheel 11 is transferred to the outer peripheral portion of the grooved grinding wheel 12 to form or shape the groove 12a. In this way, truing of the grooved grinding wheel 12 can be easily performed. The truing grindstone 11 is formed to a shape that takes into account the slight changes in cross-sectional shape that occur during truing of the inclined grooved grindstone 12, based on an empirical prediction.

In addition, the wear resistance of the grinding wheel is, for example, stronger for a GC grinding wheel with a grain size of #320 than for a resin-bonded grinding wheel with a grain size of #3000, and stronger for a metal-bonded grinding wheel with a grain size of #800 than for a GC grinding wheel with a grain size of #320. Therefore, a GC grinding wheel with a grain size of #320 can be ground with a metal-bonded grinding wheel with a grain size of #800 to form a desired cross-sectional shape. In addition, the shape of the groove can be shaped by pressing a GC grinding wheel with a grain size of #320 against the inner peripheral surface of a groove provided in a resin-bonded grinding wheel with a grain size of #3000. In addition, each grinding wheel described below basically has the grain size described above. In a conventional workpiece processing device that performs rough grinding using a metal-bonded grinding wheel with a formed groove and precision grinding using a resin-bonded grinding wheel with an inclined groove, a truing grinding wheel made of a GC grinding wheel is brought into contact with the inner peripheral surface of the formed groove of the metal-bonded grinding wheel to transfer the shape of the formed groove. The truing wheel made of a GC grinding wheel is then brought into contact with the inclined resin-bonded grinding wheel to form or shape the groove. The groove of the inclined grooved grinding wheel made of a resin-bonded grinding wheel thus formed is used to perform precision grinding of the workpiece (wafer). As a result, the workpiece can only be formed into a cross-sectional shape that depends on the shape of the formed groove of the metal-bonded grinding wheel, and cannot be formed into a different cross-sectional shape.

In contrast, in the present invention, the truing grindstone 11 made of a GC grindstone can be formed into any cross-sectional shape by the concave grinding portion 5b of the grindstone 5 made of a metal bond grindstone, so that a groove 12a of any cross-sectional shape can be formed in the grooved grindstone 12 trued by the truing grindstone 11. This makes it possible to process workpieces 2 of various cross-sectional shapes without replacing the grindstone. In addition, after truing the grooved grindstone 12, the workpiece 2 can be processed once, and the cross-sectional shape of the processed workpiece 2 can be actually measured and compared with the target shape for feedback. If the cross-sectional shape of the processed workpiece 2 differs from the target shape, the cross-sectional shape of the truing grindstone 11 that is shaped by the concave grinding portion 5b of the grindstone 5 is changed (corrected), and the grooved grindstone 12 is re-trued by the truing grindstone 11 having the changed cross-sectional shape. In this way, the cross-sectional shape of the workpiece 2 shaped by the grooved grindstone 12 can be made closer to the target shape. The conventional workpiece processing device described above uses a metal-bonded grinding wheel with a formed groove, so 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 truing grinding wheel 11. However, with the method of the present invention, it is possible to significantly improve the accuracy of the cross-sectional shape of the processed workpiece, i.e., the processing accuracy of the workpiece 2.

Next, a fourth embodiment of the present invention will be described. FIG. 15 is a front view showing a schematic diagram of a workpiece machining device of this embodiment. The workpiece machining device of this embodiment has a grooved grindstone 12 arranged obliquely with respect to the tangent direction of the outer periphery of a disk-shaped workpiece 2, similar to the third embodiment. A grindstone 5 similar to the third embodiment is attached to a grindstone support mechanism 7 and can rotate around a rotation axis 6. The workpiece 2 is attached to a workpiece support mechanism 4 and can rotate around a rotation axis 3, and can move in a plane parallel to the workpiece 2 and the grindstone 5 (in a plane perpendicular to the rotation axis 3 and the rotation axis 6) in both a direction approaching the grindstone 5 and a direction away from the grindstone 5, and can move in a plane perpendicular to the grindstone 5 and the workpiece 2 (in a plane parallel to the rotation axis 3 and the rotation axis 6) in both a direction approaching the grindstone 5 and a direction away from the grindstone 5. As shown in FIG. 15 , the workpiece support mechanism 4 has an X-direction moving stage 4a, a Y-direction moving stage 4b, a Z-direction moving stage 4c, and a motor 4d. The X-direction moving stage 4a is movable in the width direction of the grindstone 5 and the workpiece 2 (direction perpendicular to the paper surface of FIG. 15) in a plane parallel to the grindstone 5 and the workpiece 2. The Y-direction moving stage 4b is mounted on the X-direction moving stage 4a and is movable in the approaching and separating direction of the grindstone 5 and the workpiece 2 (left and right direction in FIG. 15) in a plane parallel to the grindstone 5 and the workpiece 2. The Z-direction moving stage 4c is mounted on the Y-direction moving stage 4b and is movable in the height direction (up and down direction in FIG. 15) in a plane perpendicular to the grindstone 5 and the workpiece 2. Although not described in detail, the X-direction moving stage 4a, the Y-direction moving stage 4b, and the Z-direction moving stage 4c each have a known guide means (e.g., LM guide) and a moving means (e.g., a ball screw, a nut, and a rotation driving means), and are movable in each of the directions described above. The motor 4d is mounted on the Z-direction moving stage 4c, and is a driving means for supporting the workpiece 2 via the rotating shaft 3 and rotating the rotating shaft 3. The motor 4d is a heat generating member, and a temperature adjustment mechanism 15 is provided to cover 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 allowing a liquid or gas to flow through a flow path (not shown).

This workpiece processing device can achieve the effects of each of the first to third embodiments described above. In addition, although not shown, a truing grindstone 11 similar to that of the third embodiment can be moved so as to come into contact with the grooved grindstone 12 while rotating, thereby truing the grooved grindstone 12 easily, efficiently, and with high precision.

The work support mechanism 4 does not always rotate the work 2 at high speed, but may rotate it at low speed or may not rotate the work 2 at all. Specifically, when grinding the work 2 with the concave grinding portion 5b or the cross-sectionally rectangular grinding portion 5g of the grinding wheel 5, the work 2 is rotated at high speed. When grinding the work 2 with the grooved grinding wheel 12 arranged diagonally with respect to the tangent direction of the outer periphery of the disk-shaped work 2, the work 2 is rotated at low speed. When replacing the work 2, the work support mechanism 4 does not need to perform rotational motion. Conventionally, when multiple workpieces 2 are continuously processed, the work support mechanism 4 repeats high-speed rotation of the work 2 around the rotating shaft 3, low-speed rotation of the work 2, and a state in which the rotational motion is stopped. The work support mechanism 4 heats up and becomes high temperature when the work 2 rotates at high speed, becomes lower than when the work 2 rotates at low speed, and becomes even lower when the rotational motion is stopped. As a result of the work support mechanism 4 repeating such temperature changes, deformation such as expansion and contraction occurs, especially in the rotating shaft 3. If the rotating shaft 3 on which the workpiece 2 is attached deforms and the position of the workpiece 2 in the thickness direction changes, the machining accuracy will decrease significantly even if the workpiece 2 and the grinding wheel are moved relative to each other using numerical control as described above.

Therefore, in each embodiment of the present invention, a temperature adjustment mechanism 15 is provided that is attached to the work support mechanism 4. The temperature adjustment mechanism 15 generates a flow of liquid or gas to reduce temperature fluctuations in the rotating shaft 3 of the work support mechanism 4 and suppress deformation of the rotating shaft 3. In this way, by suppressing deformation of the rotating shaft 3 due to heat when machining the workpiece 2, a decrease in the machining accuracy of the workpiece 2 is prevented.

In addition, in order to keep the temperature of the rotating shaft 3 as constant as possible, it is preferable to continue the rotational motion around the rotating shaft 3. For example, even when the workpiece 2 is replaced or replenished or the processing of the workpiece 2 is interrupted due to a problem in the work process, it is preferable for the workpiece support mechanism 4 to continue the rotational motion around the rotating shaft 3. In this way, by keeping the workpiece support mechanism 4 in a state in which the workpiece 2 is not attached and the workpiece 2 is not being processed and the rotational motion around the rotating shaft 3 is being performed (for convenience, referred to as an idling state or preliminary rotation operation), it is possible to suppress temperature fluctuations to a small level and make it easier for the temperature to stabilize in a short time. Furthermore, in this preliminary rotation operation, instead of performing only high-speed rotation or only low-speed rotation, it is preferable to alternate between high-speed rotation (rotation at the same speed as when the workpiece 2 is rotated at high speed during processing by the grindstone) and low-speed rotation (rotation at the same speed as when the workpiece 2 is rotated at low speed during processing by the grindstone) as in the actual processing of the workpiece 2, in order to suppress temperature fluctuations to a small level. As a result, when the preliminary rotation operation is switched to the processing of the workpiece 2, the temperature of the rotating shaft 3 can be immediately stabilized, and high-precision processing can be performed. In particular, it is preferable to match the ratio of the duration of high-speed rotation to the duration of low-speed rotation in the preliminary rotation operation with the ratio of the duration of high-speed rotation to the duration of low-speed rotation in the actual processing of the workpiece 2, since this allows temperature management similar to that during the actual processing of the workpiece 2. However, if the duration of high-speed rotation to the duration of low-speed rotation in the preliminary rotation operation is long, when the actual processing of the workpiece 2 is started, the waiting time for waiting for the appropriate timing (for example, the timing when the rotation speed of the preliminary rotation operation is switched) to end the preliminary rotation operation becomes long, and the working efficiency may decrease. Therefore, it is preferable to match the ratio of the duration of high-speed rotation to the duration of low-speed rotation in the preliminary rotation operation with the ratio of the duration of high-speed rotation to the duration of low-speed rotation in the actual processing of the workpiece 2, as described above, and make the duration of high-speed rotation and the duration of low-speed rotation in the preliminary rotation operation shorter than the duration of high-speed rotation and the duration of low-speed rotation in the actual processing of the workpiece 2. This allows temperature control similar to that used when actually machining the workpiece 2 to keep temperature changes in the rotating shaft 3 to a minimum, preventing a decrease in machining accuracy, and also shortens the waiting time when transitioning from the preliminary rotation operation to machining the workpiece 2, preventing a decrease in work efficiency.

The grinding wheel 5 of the present invention has a cross-sectional shape in which the concave grinding portion 5b in a cross section passing through the rotation axis 6 of the grinding wheel 5 has a cross-sectional shape in which a pair of arc-shaped portions 5e located at both ends in the thickness direction are connected by a straight portion 5f. It is preferable that the arc-shaped portion 5e at one end in the thickness direction of the grinding wheel 5 and the arc-shaped portion 5e at the other end are individually formed so that the average value of the respective radii of curvature is a desired size. As a result, both the one end and the other end in the thickness direction can be formed with high accuracy and good quality compared to the case where the entire concave grinding portion 5b is processed to have the same radius of curvature. It is preferable to reduce the respective errors in the radius of curvature of the arc-shaped portion 5e at one end in the thickness direction and the arc-shaped portion 5e at the other end. For example, the difference between the maximum and minimum values of the radius of curvature of the arc-shaped portion 5e at one end in the thickness direction and the difference between the maximum and minimum values of the radius of curvature of the arc-shaped portion 5e at the other end are both within the allowable range, i.e., are less than a predetermined value (first predetermined value). Also, the difference between the average value of the radius of curvature of the arc-shaped portion 5e at one end in the thickness direction and the average value of the radius of curvature of the arc-shaped portion 5e at the other end is both within the allowable range, i.e., are less than a predetermined value (second predetermined value).

In the present invention, as described above, a grindstone 5 having a concave ground portion 5b on its outer periphery, the concave ground portion 5b having arc-shaped portions 5e at both ends in the thickness direction and a straight portion 5f between the arc-shaped portions 5e at both ends, is used to form a disk-shaped workpiece 2 into a desired cross-sectional shape. This workpiece machining method includes a step of arranging the workpiece 2 and the grindstone 5 parallel to each other, and a step of rotating the grindstone 5 and rotating the workpiece 2 about a rotation axis 3 parallel to the rotation axis 6 of the grindstone 5, while moving the grindstone 5 relatively to the workpiece 2 according to a movement condition calculated based on the radius of curvature of the arc-shaped portion 5e of the grindstone 5 so that the contact portion between the concave ground portion 5b and the workpiece 2 moves along the desired cross-sectional shape of the workpiece 2. The step of moving the grinding wheel 5 relative to the workpiece 2 includes: rotating the workpiece 2 and the grinding wheel 5, while moving the arc-shaped portion 5e of the concave grinding portion 5b of the grinding wheel 5 in a curved manner relative to the workpiece 2 from the outer peripheral end face of the workpiece 2 toward one side by an angle calculated in advance in accordance with the movement conditions, thereby grinding the outer periphery of one side of the workpiece 2; moving the grinding wheel 5 along the outer peripheral end face of the workpiece 2 from one side to the other side by a curved manner relative to the workpiece 2 while rotating the workpiece 2 and the grinding wheel 5, while moving the arc-shaped portion 5e of the concave grinding portion 5b of the grinding wheel 5 in a curved manner relative to the workpiece 2 from the outer peripheral end face of the workpiece 2 toward the other side by an angle calculated in advance in accordance with the movement conditions, thereby grinding the outer periphery of the other side of the workpiece 2. When rough grinding the outer periphery of one side or the other side of the workpiece 2, while rotating the workpiece 2 and the grinding wheel 5, the arc-shaped portion 5e of the concave grinding portion 5b of the grinding wheel 5 is moved curvedly relative to the workpiece 2 from the outer peripheral end face of the workpiece 2 toward one side or the other side by an angle calculated in advance in accordance with the movement conditions so that the rotation axis 6 of the grinding wheel 5 and the rotation axis 3 of the workpiece 2 are positioned in the same plane (along the arrow F1 in Figure 16), and then the relative movement of the grinding wheel 5 with respect to the workpiece 2 is stopped. On the other hand, when performing precise grinding of the outer periphery of one side or the other side of the workpiece 2, while rotating the workpiece 2 and the grinding wheel 5, the arc-shaped portion 5e of the concave grinding portion 5b of the grinding wheel 5 is moved curvilinearly relative to the workpiece 2 from the outer peripheral end face toward one side or the other side of the workpiece 2 by an angle calculated in advance in accordance with the above-mentioned movement conditions so that the rotation axis 6 of the grinding wheel 5 and the rotation axis 3 of the workpiece 2 are positioned in the same plane (along the arrow F1 in Figure 16), and then the grinding wheel 5 is moved linearly relative to the workpiece 2 so that the rotation axis 6 of the grinding wheel 5 and the rotation axis 3 of the workpiece 2 move relatively in a plane extending in a direction perpendicular or obliquely intersecting the plane in which the rotation axis 6 of the grinding wheel 5 and the rotation axis 3 of the workpiece 2 were positioned during the curvilinear movement (for example, along any of the arrows F2, F3, F4, or F5 in Figure 16).

According to this method, the roughness of the ground portion of the workpiece 2 is improved (becomes smoother). The reason for this is that the surface of the grindstone 5 (the surface used for grinding) is dotted with portions where abrasive grains such as diamonds protrude. In the contact portion of the workpiece 2 with the grindstone 5, the portion where the portion of the grindstone 5 where abrasive grains such as diamonds protrude contacts the workpiece 2 is engraved deeper than other portions. Then, the grindstone 5 is moved linearly relative to the workpiece 2, so that the entire area including the deeply engraved portion of the workpiece 2 is ground again by the arc-shaped portion 5e of the concave grinding portion 5b of the grindstone 5. As a result, the portion deeply engraved by contact with the abrasive grains such as diamonds in the previous process is not left as it is, but is ground and smoothed by contacting the arc-shaped portion 5e of the concave grinding portion 5b of the grindstone 5. In particular, by changing the relative movement direction between the rotation axis 6 of the grinding wheel 5 and the rotation axis 3 of the workpiece from the previous process, and moving the workpiece 2 relative to the grinding wheel 5 in a direction that intersects perpendicularly or obliquely with the relative movement direction between the grinding wheel 5 and the workpiece 2 during the curved movement, and in a direction that is obliquely or perpendicular to the rotation direction of the workpiece 2, it is possible to re-grind areas including those that were deeply engraved by contact with abrasive grains such as diamonds in the previous process, and it is also possible to prevent the workpiece 2 from being excessively ground by the arc-shaped portion 5e of the concave grinding portion 5b of the grinding wheel 5, resulting in an angle that becomes too small.

In the present invention, a disk-shaped workpiece 2 may be formed into a desired cross-sectional shape by using a grindstone 5 having a concave grinding portion 5b on its outer periphery, the concave grinding portion 5b having an arc-shaped portion 5e at both ends in the thickness direction, an inclined surface portion 5h located outside the arc-shaped portion 5e in the thickness direction and continuously connected to the arc-shaped portion 5e, and a straight portion 5f between the arc-shaped portions 5e at both ends. This workpiece machining method includes a step of arranging the workpiece 2 and the grindstone 5 parallel to each other, and a step of rotating the grindstone 5 and rotating the workpiece 2 about a rotation axis 3 parallel to the rotation axis 6 of the grindstone 5, while moving the grindstone 5 relatively to the workpiece 2 according to a moving condition calculated based on the radius of curvature of the arc-shaped portion 5e of the grindstone 5 so that the contact portion between the concave grinding portion 5b and the workpiece 2 moves along the desired cross-sectional shape of the workpiece 2. The step of moving the grinding wheel 5 relative to the workpiece 2 includes: rotating the workpiece 2 and the grinding wheel 5, while moving the arc-shaped portion 5e of the concave grinding portion 5b of the grinding wheel 5 in a curved manner relative to the workpiece 2 from the outer peripheral end face of the workpiece 2 toward one side by an angle calculated in advance in accordance with the movement conditions, thereby grinding the outer periphery of one side of the workpiece 2; moving the grinding wheel 5 along the outer peripheral end face of the workpiece 2 from one side to the other side by a curved manner relative to the workpiece 2, while rotating the workpiece 2 and the grinding wheel 5, while moving the arc-shaped portion 5e of the concave grinding portion 5b of the grinding wheel 5 in a curved manner relative to the workpiece 2 from the outer peripheral end face of the workpiece 2 toward the other side by an angle calculated in advance in accordance with the movement conditions, thereby grinding the outer periphery of the other side of the workpiece 2. When rough grinding the outer periphery of one side or the other side of the workpiece 2, while rotating the workpiece 2 and the grinding wheel 5, the arc-shaped portion 5e of the concave grinding portion 5b of the grinding wheel 5 is moved curvedly relative to the workpiece 2 from the outer peripheral end face of the workpiece 2 toward one side or the other side by an angle calculated in advance in accordance with the above-mentioned movement conditions so that the rotation axis 6 of the grinding wheel 5 and the rotation axis 3 of the workpiece 2 are positioned in the same plane (along the arrow F1 in Figure 16), and then the relative movement of the grinding wheel 5 with respect to the workpiece 2 is stopped. On the other hand, when performing precise grinding of the outer periphery of one side or the other side of the workpiece 2, while rotating the workpiece 2 and the grinding wheel 5, the arc-shaped portion 5e of the concave grinding portion 5b of the grinding wheel 5 is moved in a curved manner relative to the workpiece 2 from the outer peripheral end face toward one side or the other side of the workpiece 2 by an angle calculated in advance in accordance with the above-mentioned movement conditions so that the rotation axis 6 of the grinding wheel 5 and the rotation axis 3 of the workpiece 2 are located in the same plane (along the arrow F1 in Figure 16), and then the grinding wheel 5 is moved linearly relative to the workpiece 2 while maintaining the state in which the rotation axis 6 of the grinding wheel 5 and the rotation axis 3 of the workpiece 2 are located in the plane in which the rotation axis 6 of the grinding wheel 5 and the rotation axis 3 of the workpiece 2 were located during the curved movement (continuing to move along the arrow F1 in Figure 16).

According to this method, since the concave grinding portion 5b of the grindstone 5 is provided with a slope portion 5h, the area including the portion deeply engraved by contact with abrasive grains such as diamond is ground again by the slope portion 5h of the grindstone 5, and the portion deeply engraved by contact with abrasive grains such as diamond in the previous process is smoothed without remaining as it is. And, since the workpiece 2 is ground by the slope portion 5h at the end, there is no risk of the angle becoming small due to excessive grinding. Therefore, there is no need to change the moving direction between the curved relative movement of the grindstone 5 and the workpiece 2 and the subsequent linear relative movement, and the workpiece 2 may be pulled out straight when viewed in a plane.

In addition, in the present invention, a workpiece processing method for forming a disk-shaped workpiece 2 into a desired cross-sectional shape using a grinding wheel 5 having a concave grinding portion 5b on its outer periphery, in which the concave grinding portion 5b has a shape having arc-shaped portions 5e at both ends in the thickness direction and a straight portion 5f between the arc-shaped portions 5e at both ends , includes the steps of arranging the workpiece 2 and the grinding wheel 5 parallel to each other, and rotating the grinding wheel 5 and rotating the workpiece 2 about a rotation axis 3 parallel to the rotation axis 6 of the grinding wheel 5, while moving the grinding wheel 5 relative to the workpiece 2 in accordance with movement conditions calculated based on the radius of curvature of the arc-shaped portion 5e of the grinding wheel 5 so that the contact portion between the concave grinding portion 5b and the workpiece 2 moves along the desired cross-sectional shape of the workpiece 2. The step of moving the grinding wheel 5 relative to the workpiece 2 includes: rotating the workpiece 2 and the grinding wheel 5, while moving the arc-shaped portion 5e of the concave grinding portion 5b of the grinding wheel 5 in a curved manner relative to the workpiece 2 from the outer peripheral end face of the workpiece 2 toward one side by an angle calculated in advance in accordance with the movement conditions, thereby grinding the outer periphery of one side of the workpiece 2; moving the grinding wheel 5 along the outer peripheral end face of the workpiece 2 from one side to the other side by a curved manner relative to the workpiece 2 while rotating the workpiece 2 and the grinding wheel 5, while moving the arc-shaped portion 5e of the concave grinding portion 5b of the grinding wheel 5 in a curved manner relative to the workpiece 2 from the outer peripheral end face of the workpiece 2 toward the other side by an angle calculated in advance in accordance with the movement conditions, thereby grinding the outer periphery of the other side of the workpiece 2. When rough grinding the outer periphery of one side or the other side of the workpiece 2, while rotating the workpiece 2 and the grinding wheel 5, the arc-shaped portion 5e of the concave grinding portion 5b of the grinding wheel 5 is moved in a curved manner relative to the workpiece 2 from the outer peripheral end face of the workpiece 2 toward one side or the other side by an angle calculated in advance in accordance with the movement conditions, and then the relative movement of the grinding wheel 5 with respect to the workpiece 2 is stopped. When performing precise grinding of the outer periphery on one side of the workpiece 2, while rotating the workpiece 2 and the grinding wheel 5, taking into account the positional error in the thickness direction that occurs when the workpiece 2 rotates, the arc-shaped portion 5e of the concave grinding portion 5b of the grinding wheel 5 is moved curvedly relative to the workpiece 2 from the outer peripheral end face of the workpiece 2 toward one side by an angle calculated in advance in accordance with the movement conditions, and then the movement is stopped.At a position where the grinding wheel 5 _contacts the slope of the chamfered portion 2a on one side of the workpiece 2, the rotational speed of the workpiece 2 is slowed down while adjusting the position in the thickness direction of the workpiece 2, and the workpiece 2 is rotated at least one rotation, thereby grinding one side of the workpiece 2 while canceling out the positional error during rotation of the workpiece 2. When precisely grinding the outer periphery of the other side of the workpiece 2, while rotating the workpiece 2 and the grinding wheel 5, taking into account the positional error in the thickness direction that occurs when the workpiece 2 rotates, the arc-shaped portion 5e of the concave grinding portion 5b of the grinding wheel 5 is moved in a curved manner relative to the workpiece 2 from the outer peripheral end face of the workpiece 2 toward the other side by an _angle that is calculated in advance in accordance with the above-mentioned movement conditions, and then the movement is stopped.At a position where the grinding wheel 5 contacts the slope of the chamfered portion 2a on the other side of the workpiece 2, the rotational speed of the workpiece 2 is slowed down while adjusting the position in the thickness direction of the workpiece 2, and the workpiece 2 is rotated at least one rotation, thereby grinding the other side of the workpiece 2 while canceling out the positional error during rotation of the workpiece 2.

The technical significance of this method is that when the workpiece 2 and grinding wheel 5 are rotated as in the above-mentioned embodiments, the position in the direction parallel to the rotation axis (thickness direction) may be displaced during rotation. Generally, an error of about ±1.5 μm to ±3 μm occurs in the thickness direction position. Due to such an error in the thickness direction, the planar shape of the workpiece 2 after grinding also varies greatly. In particular, when the angles θ1 and θ2 of the workpiece 2 shown in Figures 7(A) and 8 are small, the positional deviation in the thickness direction causes a large positional deviation in the horizontal direction (in-plane direction). Specifically, as shown in Figure 7(B) as a schematic diagram, assuming a right-angled triangle with the upper thickness direction positional deviation O1 as the opposite side and the horizontal direction positional deviation K1 as the base, tan θ1 = O1/K1, i.e., K1 = O1/tan θ1. Similarly, as shown in FIG. 7C, assuming a right-angled triangle with the lower thickness misalignment O2 as the opposite side and the horizontal misalignment K2 as the base, tan θ2=O2/K2, i.e., K2=O2/tan θ2. For example, when the angles θ1 and θ2 are 22°, the horizontal misalignments K1 and K2 are about 2.5 times the thickness misalignments O1 and O2. Therefore, when the thickness misalignments O1 and O2 are ±3 μm, the horizontal misalignments K1 and K2 are about ±7.5 μm. The R-shaped workpiece 2 shown in FIG. 8 also has a relationship between the horizontal misalignments K1 and K2 and the thickness misalignments O1 and O2 (see FIGS. 7B to 7C) similar to that of the T-shaped workpiece 2 shown in FIG. 7A. As mentioned above, there is a possibility that an error of up to about 7.5 μm may occur in the dimensions of the upper and lower surfaces of the workpiece 2 (for example, the dimensions A1 and A2 shown in FIGS. 7A and 8). If the angles θ1 and θ2 are smaller, the error in the dimensions (e.g., dimensions A1 and A2) of the upper and lower surfaces of the workpiece 2 becomes even larger. Therefore, it is possible to investigate the tendency of the positional deviation in the thickness direction of the workpiece 2 during rotation, incorporate a piezoelectric element (not shown) in the workpiece support mechanism 4, and move the workpiece 2 in the thickness direction so as to cancel the positional deviation in the thickness direction by operating the piezoelectric element at high speed and finely while the workpiece 2 is rotating. However, in this case, the structure of the workpiece support mechanism 4 becomes very complicated, which leads to high costs and is prone to failure. If the workpiece 2 is moved up and down at high speed in accordance with the high-speed rotation of the workpiece 2, the shape of the workpiece 2 after grinding will no longer be smooth, and the accuracy of the workpiece dimensions (e.g., radii of curvature R1 and R2 shown in Figures 7(A) and 8) may deteriorate. If these problems are solved by slowing down the rotation speed of the workpiece 2, the work efficiency decreases and the processing cost increases.

Therefore, in order not to reduce the work efficiency too much, it is preferable to operate the device for moving the work 2 up and down and the associated movement of the work 2 in the thickness direction only as necessary, rather than constantly while the work 2 is rotating. Specifically, before performing precision grinding of the outer periphery of one surface side (upper surface side) and the other surface side (lower surface side) of the work 2, the positional deviation state in the thickness direction when the work 2 is rotated by the work support mechanism 4 is checked. That is, while actually rotating the work 2 by the work support mechanism 4, for example, the variation in the height direction of eight points H1 to H8 shown in FIG. 17 is measured. Then, among the heights of the points H1 to H8, the positive value H _max (for example, about +3 μm) that is the largest difference from the midpoint of those heights and the negative value H _min (for example, about −3 μm) that is the largest difference are obtained. Then, while rotating the workpiece 2 and the grinding wheel 5, the circular arc portion 5e of the concave grinding portion 5b of the grinding wheel 5 is moved in a curved _manner relative to the workpiece 2 from the outer peripheral end surface of the workpiece 2 toward the upper surface thereof by an angle calculated in advance according to the movement conditions, based on the highest point H max in the thickness direction, and then the movement is stopped. Then, at a position where the grinding wheel 5 contacts the slope of the chamfered portion 2a on the upper surface side of the workpiece 2, the rotation speed of the workpiece 2 is slowed down while adjusting the position in the thickness direction of the workpiece 2, and the workpiece 2 is rotated at least one revolution, thereby grinding the upper surface side of the workpiece 2 while canceling out the position error during the rotation of the workpiece 2. Similarly, while rotating the workpiece 2 and the grinding wheel 5, the circular arc portion _5e of the concave grinding portion 5b of the grinding wheel 5 is moved in a curved manner relative to the workpiece 2 from the outer peripheral end surface of the workpiece 2 toward the lower surface thereof by an angle calculated in advance according to the movement conditions, based on the lowest point H min in the thickness direction, and then the movement is stopped. Then, at a position where the grinding wheel 5 contacts the slope of the chamfered portion 2a on the underside of the workpiece 2, the rotational speed of the workpiece 2 is slowed down and the workpiece 2 is rotated at least one revolution while adjusting the position in the thickness direction of the workpiece 2, thereby grinding the underside of the workpiece 2 while canceling out positional errors occurring during rotation of the workpiece 2.

According to this method, in the final stage of the grinding process, the work 2 is ground while moving it in the thickness direction so as to cancel out the position error during the rotation of the work 2, so that the ground surface becomes smooth and the desired cross-sectional shape can be formed with high accuracy. Moreover, the movement of the work 2 in the thickness direction and the low-speed rotation of the work 2 may be only one or several rotations, which is the final stage of the grinding process, and in the previous stage, the work 2 is not moved in the thickness direction and is ground while rotating at high speed. Therefore, it is possible to prevent a large positional deviation in the horizontal direction (in-plane direction), which is the most important dimension in the cross-sectional shape caused by a slight positional deviation in the thickness direction, and the effect of the concave-shaped grindstone and the obtuse angle connection make it possible to almost ignore the influence of the joint between the cross-section R and the inclined surface portion, so that high-precision processing is possible, and the work efficiency does not decrease much and the device is unlikely to break down. Since the movement of the work 2 in the thickness direction is performed when the work 2 is rotating at a low speed, expensive devices such as piezoelectric elements are not required, and it can be performed using ball screws or the like. Thus, according to this method, the processing precision of the work 2 is good, the work efficiency is good, and the processing cost is not very high. This method can also be combined with the previously described method in which grinding is performed while performing a curvilinear relative movement between the grinding wheel 5 and the workpiece 2, followed by a linear relative movement.

[Appendix 1]
A workpiece machining apparatus for forming a disk-shaped workpiece into a desired cross-sectional shape,
The grinding machine includes a workpiece support mechanism that supports the workpiece, a disk-shaped grinding wheel that is arranged parallel to the workpiece, and a grinding wheel support mechanism that supports the grinding wheel,
the workpiece support mechanism rotates the workpiece, the grindstone support mechanism rotates the grindstone, a rotation axis about which the workpiece is rotated by the workpiece support mechanism and a rotation axis about which the grindstone is rotated by the grindstone support mechanism are parallel to each other,
the workpiece support mechanism has an adsorption member that adsorbs only one side of the workpiece, the adsorption member having a planar shape that is a circle having a radius smaller than the radius of the workpiece, and an outer peripheral portion of the circular adsorption member having a tapered shape that becomes thinner toward the outside,
the grinding wheel has a concave grinding portion on its outer periphery, the cross-sectional shape of the concave grinding portion in a cross section along the rotation axis of the grinding wheel is concave from the outer periphery toward the inner periphery, has an arc-shaped portion at least at both ends in a thickness direction, and has a straight portion having a thickness equal to or greater than the thickness of the workpiece between the arc-shaped portions at both ends;
The grindstone and the workpiece can be moved relatively toward or away from each other by the grindstone support mechanism or the workpiece support mechanism,
the grindstone support mechanism or the workpiece support mechanism moves the grindstone relative to the workpiece in accordance with a movement condition calculated based on a radius of curvature of the arc-shaped portion of the grindstone so that a contact portion between the concave grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece;
a radius of curvature of the arc-shaped portion of the grindstone is at least 10 times the thickness of the workpiece so that the arc-shaped portion of the grindstone abuts against the workpiece without generating a substantial gap between the arc-shaped portion and the chamfered portion of the desired cross-sectional shape of the workpiece;
A workpiece machining apparatus characterized in that the arc-shaped portion located on the one side of the workpiece that is adsorbed by the suction member has a length that is less than the length at which it abuts the tapered shape of the suction member when it is in contact with the end of the one side of the workpiece at a position where a tangent to the arc-shaped portion extends at an angle that matches the angle of the tapered shape of the suction member in a cross section along the rotation axis of the grinding wheel, and has a length that is greater than or equal to the length of the chamfered portion on the one side of the workpiece having the desired cross-sectional shape.

[Appendix 2]
A workpiece machining apparatus for forming a disk-shaped workpiece into a desired cross-sectional shape,
The grinding machine includes a workpiece support mechanism that supports the workpiece, a disk-shaped grinding wheel that is arranged parallel to the workpiece, and a grinding wheel support mechanism that supports the grinding wheel,
the workpiece support mechanism rotates the workpiece, the grindstone support mechanism rotates the grindstone, a rotation axis about which the workpiece is rotated by the workpiece support mechanism and a rotation axis about which the grindstone is rotated by the grindstone support mechanism are parallel to each other,
the workpiece support mechanism has an adsorption member that adsorbs only one side of the workpiece, the adsorption member having a planar shape that is a circle having a radius smaller than the radius of the workpiece, and an outer peripheral portion of the circular adsorption member having a tapered shape that becomes thinner toward the outside,
the grinding wheel has a concave grinding portion on its outer periphery, the cross-sectional shape of the concave grinding portion in a cross section along the rotation axis of the grinding wheel is concave from the outer periphery toward the inner periphery, and has at least an arc-shaped portion at each end in the thickness direction, and an inclined surface portion located outside the arc-shaped portion in the thickness direction and continuously connected to the arc-shaped portion, and has a straight portion having a thickness equal to or greater than the thickness of the workpiece between the arc-shaped portions at each end,
The grindstone and the workpiece can be moved relatively toward or away from each other by the grindstone support mechanism or the workpiece support mechanism,
the grindstone support mechanism or the workpiece support mechanism moves the grindstone relative to the workpiece in accordance with a movement condition calculated based on a radius of curvature of the arc-shaped portion of the grindstone so that a contact portion between the concave grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece;
The radius of curvature of the arc-shaped portion of the grinding wheel is at least 10 times the thickness of the workpiece,
a chamfered portion on the one side of the workpiece that is attracted by the suction member, the chamfered portion having a length that is less than the length at which the sloping portion abuts the tapered shape of the suction member when it contacts the end of the one side of the workpiece at a position where a tangent to the arc-shaped portion extends at an angle that matches the angle of the tapered shape of the suction member in a cross section along the rotation axis of the grinding wheel, and the chamfered portion has a length that is greater than or equal to the length of the chamfered portion on the one side of the workpiece having the desired cross-sectional shape.

[Appendix 3]
The workpiece processing device described in Appendix 1 or 2, wherein the concave grinding portion and a grinding portion having a rectangular cross section, whose surface facing the workpiece is linear and parallel to the thickness direction of the grinding wheel in a cross section along the rotation axis, are arranged side by side in the thickness direction on the outer periphery of the grinding wheel, and the grinding portion having a rectangular cross section of the grinding wheel abuts against the outer periphery of the workpiece before grinding is performed by the concave grinding portion, and grinds the workpiece so as to reduce the radius of the workpiece by moving the grinding wheel from the radial outside to the inside of the workpiece.

[Appendix 4]
The radius r1 of the attraction member is expressed by the radius r2 of the desired cross-sectional shape of the workpiece and the thickness t of the workpiece, and is given by r2-10t≦r1≦r2-5t,
The workpiece machining device according to any one of appendices 1 to 3, wherein the angle θ1 of the tapered shape of the suction member is expressed in terms of the angle θ2 of the chamfered portion of the desired cross-sectional shape of the workpiece, such that θ2-10≦θ1≦θ2+5.

[Appendix 5]
A workpiece processing device described in any one of appendix 1 to 4, wherein the grinding wheel support mechanism has a spindle to which the grinding wheel is directly or indirectly attached, and a rotary bearing portion that rotatably supports the spindle, and supports the grinding wheel so that the center of gravity of the grinding wheel is located between the mounting position of the grinding wheel and the rotary bearing portion.

[Appendix 6]
When grinding the outer periphery on one surface side of the workpiece, the grindstone support mechanism and the workpiece support mechanism rotate the workpiece and the grindstone, while moving the arc-shaped portion of the concave grinding portion of the grindstone in a curved manner relative to the workpiece from the outer periphery end face of the workpiece toward the one surface by an angle calculated in advance in accordance with the movement conditions, and when grinding the outer periphery on the other surface side of the workpiece, while rotating the workpiece and the grindstone, move the arc-shaped portion of the concave grinding portion of the grindstone in a curved manner relative to the workpiece from the outer periphery end face of the workpiece toward the other surface by an angle calculated in advance in accordance with the movement conditions,
When performing rough grinding of the outer periphery of the one surface side or the other surface side of the workpiece, the grindstone support mechanism and the workpiece support mechanism rotate the workpiece and the grindstone, move the arc-shaped portion of the concave grinding portion of the grindstone in a curved manner relative to the workpiece from the outer periphery end face of the workpiece toward the one surface side or the other surface by an angle calculated in advance in accordance with the movement conditions, and then stop the relative movement of the grindstone with respect to the workpiece;
A workpiece processing device as described in any of Appendix 1 to 5, wherein, when performing precise grinding of the outer periphery of the one surface side or the other surface side of the workpiece, the grinding wheel support mechanism and the workpiece support mechanism rotate the workpiece and the grinding wheel, move the arc-shaped portion of the concave grinding portion of the grinding wheel in a curved manner relative to the workpiece from the outer periphery end face of the workpiece toward the one surface side or the other surface by an angle calculated in advance in accordance with the movement conditions, and then move the grinding wheel in a linear manner relative to the workpiece.

[Appendix 7]
In addition to the grindstone having the concave grinding portion, the grindstone further includes a disk-shaped grooved grindstone disposed obliquely with respect to a tangent direction of the outer periphery of the workpiece and used for grinding more precisely than grinding by the concave grinding portion of the grindstone, and a grooved grindstone support mechanism for supporting the grooved grindstone,
The workpiece processing device according to any one of claims 1 to 6, wherein the grooved grindstone support mechanism rotates the grooved grindstone.

[Appendix 8]
Further comprising a truing grindstone that can be attached to the work support mechanism in place of the work,
The truing grindstone is moved relative to the grindstone in accordance with the movement conditions by the grindstone support mechanism or the work support mechanism to form an outer shape,
The workpiece processing device described in Appendix 7, characterized in that the grooved grindstone is pressed against the truing grindstone and the outer shape of the truing grindstone is transferred to form or shape a groove.

[Appendix 9]
A workpiece processing apparatus described in any one of appendix 1 to 8, wherein the workpiece support mechanism has a temperature adjustment mechanism that generates a flow of liquid or gas to keep the temperature of the rotation shaft of the workpiece support mechanism constant.

[Appendix 10]
The grinding wheel included in the workpiece processing apparatus according to claim 1 or 2,
A grinding wheel, characterized in that the straight portion has a coarser grinding grain size than the arc-shaped portion, and the arc-shaped portion is used for more precise grinding than grinding by the straight portion.

[Appendix 11]
The grinding wheel included in the workpiece processing apparatus according to claim 3,
A grinding wheel characterized in that the grinding portion having a rectangular cross section has a coarser grinding grain size than the grinding portion having a concave cross section, and the concave grinding portion is used for more precise grinding than grinding by the grinding portion having a rectangular cross section.

[Appendix 12]
The grinding wheel included in the workpiece processing apparatus according to any one of appendixes 1 to 9,
A grinding wheel, characterized in that the arc-shaped portion at one end in the thickness direction and the arc-shaped portion at the other end are individually formed so that the average value of the radius of curvature of each is a desired size.

[Appendix 13]
The grinding wheel included in the workpiece processing apparatus according to any one of appendixes 1 to 9,
a difference between a maximum value and a minimum value of a radius of curvature of the arc-shaped portion at one end in a thickness direction and a difference between a maximum value and a minimum value of a radius of curvature of the arc-shaped portion at the other end are both equal to or smaller than a first predetermined value;
A grinding wheel, characterized in that the difference between the average value of the radius of curvature of the arc-shaped portion at one end in the thickness direction and the average value of the radius of curvature of the arc-shaped portion at the other end is a second predetermined value or less.

[Appendix 14]
The grinding wheel included in the workpiece processing apparatus according to any one of appendixes 1 to 9,
A grinding wheel having a straight or tapered mounting hole extending in the thickness direction.

[Appendix 15]
A method for machining a workpiece for forming a disc-shaped workpiece into a desired cross-sectional shape using a rotatable disc-shaped grinding wheel having a concave grinding portion on its outer periphery, the concave grinding portion having a cross-sectional shape recessed from the outer periphery toward the inner periphery in a cross section along a rotation axis of the grinding wheel, the concave grinding portion having an arc-shaped portion at least at both ends in a thickness direction, and a straight portion having a thickness equal to or greater than the thickness of the workpiece between the arc-shaped portions at both ends, the method comprising the steps of:
placing the workpiece and the grindstone parallel to each other;
and rotating the grindstone and the workpiece about a rotation axis parallel to the rotation axis of the grindstone, while moving the grindstone relative to the workpiece in accordance with a movement condition calculated based on a radius of curvature of the arc-shaped portion of the grindstone such that a contact portion between the concave grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece,
The step of moving the grindstone relative to the workpiece includes:
While rotating the workpiece and the grindstone, the arc-shaped portion of the concave grinding portion of the grindstone is moved in a curved manner relative to the workpiece from the outer peripheral end face of the workpiece toward one surface by an angle calculated in advance according to the movement conditions, thereby grinding the outer peripheral portion of the one surface side of the workpiece;
Moving the grindstone relative to the workpiece from the one surface side to the other surface side along an outer peripheral end surface of the workpiece;
and rotating the workpiece and the grindstone, and moving the arc-shaped portion of the concave grinding portion of the grindstone in a curved manner from the outer peripheral end face of the workpiece toward the other surface by an angle calculated in advance 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 periphery of the one surface side or the other surface side of the workpiece, while rotating the workpiece and the grindstone, the arc-shaped portion of the concave grinding portion of the grindstone is moved in a curved manner relative to the workpiece from the outer periphery end face of the workpiece toward the one surface or the other surface by an angle calculated in advance according to the movement conditions so that the rotation axis of the grindstone and the rotation axis of the workpiece are positioned in the same plane, and then the relative movement of the grindstone with respect to the workpiece is stopped;
A workpiece machining method, characterized in that, when performing precise grinding of the outer periphery of the one surface side or the other surface side of the workpiece, while rotating the workpiece and the grinding wheel, the arc-shaped portion of the concave grinding portion of the grinding wheel is moved curvilinearly relative to the workpiece from the outer periphery end face of the workpiece toward the one surface side or the other surface side by an angle calculated in advance in accordance with the movement conditions so that the rotation axis of the grinding wheel and the rotation axis of the workpiece are positioned in the same plane, and then the grinding wheel is moved linearly relative to the workpiece so that the rotation axis of the grinding wheel and the rotation axis of the workpiece move relatively in a plane extending in a direction intersecting perpendicularly or obliquely to the plane in which the rotation axis of the grinding wheel and the rotation axis of the workpiece were positioned during the curvilinear movement.

[Appendix 16]
A workpiece machining method for forming a disc-shaped workpiece into a desired cross-sectional shape using a grinding wheel having a rotatable disc-shaped grinding portion on its outer periphery, the cross-sectional shape of the concave grinding portion in a cross section along the rotation axis of the grinding wheel being concave recessed from the outer periphery toward the inner periphery, the grinding wheel having at least an arc-shaped portion at each end in the thickness direction, and an inclined surface portion located outside the arc-shaped portion in the thickness direction and continuously connected to the arc-shaped portion, and a straight portion having a thickness equal to or greater than the thickness of the workpiece between the arc-shaped portions at each end,
placing the workpiece and the grindstone parallel to each other;
and rotating the grindstone and the workpiece about a rotation axis parallel to the rotation axis of the grindstone, while moving the grindstone relative to the workpiece in accordance with a movement condition calculated based on a radius of curvature of the arc-shaped portion of the grindstone such that a contact portion between the concave grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece,
The step of moving the grindstone relative to the workpiece includes:
While rotating the workpiece and the grindstone, the arc-shaped portion of the concave grinding portion of the grindstone is moved in a curved manner relative to the workpiece from the outer peripheral end face of the workpiece toward one surface by an angle calculated in advance according to the movement conditions, thereby grinding the outer peripheral portion of the one surface side of the workpiece;
Moving the grindstone relative to the workpiece from the one surface side to the other surface side along an outer peripheral end surface of the workpiece;
and rotating the workpiece and the grindstone, and moving the arc-shaped portion of the concave grinding portion of the grindstone in a curved manner from the outer peripheral end face of the workpiece toward the other surface by an angle calculated in advance 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 periphery of the one surface side or the other surface side of the workpiece, while rotating the workpiece and the grindstone, the arc-shaped portion of the concave grinding portion of the grindstone is moved in a curved manner relative to the workpiece from the outer periphery end face of the workpiece toward the one surface or the other surface by an angle calculated in advance according to the movement conditions so that the rotation axis of the grindstone and the rotation axis of the workpiece are positioned in the same plane, and then the relative movement of the grindstone with respect to the workpiece is stopped;
A workpiece machining method, characterized in that, when performing precise grinding of the outer periphery of the one surface side or the other surface side of the workpiece, while rotating the workpiece and the grinding wheel, the arc-shaped portion of the concave grinding portion of the grinding wheel is moved curvilinearly relative to the workpiece from the outer periphery end face of the workpiece toward the one surface side or the other surface side by an angle calculated in advance in accordance with the movement conditions so that the rotation axis of the grinding wheel and the rotation axis of the workpiece are positioned in the same plane, and then the grinding wheel is moved linearly relative to the workpiece while maintaining the state in which the rotation axis of the grinding wheel and the rotation axis of the workpiece are positioned within the plane in which the rotation axis of the grinding wheel and the rotation axis of the workpiece were positioned during the curvilinear movement.

[Appendix 17]
A method for machining a workpiece for forming a disc-shaped workpiece into a desired cross-sectional shape using a rotatable disc-shaped grinding wheel having a concave grinding portion on its outer periphery, the concave grinding portion having a cross-sectional shape recessed from the outer periphery toward the inner periphery in a cross section along a rotation axis of the grinding wheel, the concave grinding portion having an arc-shaped portion at least at both ends in a thickness direction, and a straight portion having a thickness equal to or greater than the thickness of the workpiece between the arc-shaped portions at both ends, the method comprising the steps of:
placing the workpiece and the grindstone parallel to each other;
and rotating the grindstone and the workpiece about a rotation axis parallel to the rotation axis of the grindstone, while moving the grindstone relative to the workpiece in accordance with a movement condition calculated based on a radius of curvature of the arc-shaped portion of the grindstone such that a contact portion between the concave grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece,
The step of moving the grindstone relative to the workpiece includes:
While rotating the workpiece and the grindstone, the arc-shaped portion of the concave grinding portion of the grindstone is moved in a curved manner relative to the workpiece from the outer peripheral end face of the workpiece toward one surface by an angle calculated in advance according to the movement conditions, thereby grinding the outer peripheral portion of the one surface side of the workpiece;
Moving the grindstone relative to the workpiece from the one surface side to the other surface side along an outer peripheral end surface of the workpiece;
and rotating the workpiece and the grindstone, and moving the arc-shaped portion of the concave grinding portion of the grindstone in a curved manner from the outer peripheral end face of the workpiece toward the other surface by an angle calculated in advance 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 periphery of the one surface side or the other surface side of the workpiece, while rotating the workpiece and the grindstone, the arc-shaped portion of the concave grinding portion of the grindstone is moved in a curved manner relative to the workpiece from the outer periphery end face of the workpiece toward the one surface side or the other surface by an angle calculated in advance according to the movement condition, and then the movement of the grindstone relative 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 rotating the workpiece and the grindstone, the arc-shaped portion of the concave grinding portion of the grindstone is moved in a curved manner relative to the workpiece from the outer periphery end face of the workpiece toward the one surface side or the other surface by an angle calculated in advance according to the movement conditions, and then the movement is stopped;
When performing precise grinding of the outer periphery of the one surface side of the workpiece, while rotating the workpiece and the grindstone, the arc-shaped portion of the concave grinding portion of the grindstone is moved in a curved manner relative to the workpiece from the outer peripheral end face of the workpiece toward the one surface by an angle calculated in advance according to the movement conditions, taking into account a position error in the thickness direction that occurs when the workpiece rotates, and then the movement is stopped. At a position where the grindstone contacts the slope of the chamfered portion of the one surface side of the workpiece, the rotation speed of the workpiece is slowed down and the workpiece is rotated at least one revolution while adjusting the position in the thickness direction of the workpiece, thereby grinding the one surface side of the workpiece while canceling out the position error during the rotation of the workpiece.
a grinding wheel that is rotated in a direction parallel to the outer periphery of the workpiece and a grinding wheel that is moved in a curved manner relative to the workpiece by an angle calculated in advance in accordance with the movement conditions from the outer periphery end face of the workpiece toward the other surface of the workpiece, based on the outermost position on the other surface side in the thickness direction through which the workpiece passes when rotating, taking into account a positional error in the thickness direction that occurs when the workpiece rotates, and then the movement is stopped.The rotation speed of the workpiece is slowed down and the workpiece is rotated at least one revolution while adjusting the position in the thickness direction of the workpiece at a position where the grinding wheel contacts the slope of the chamfered portion on the other surface side of the workpiece, thereby grinding the other surface side of the workpiece while canceling out the positional error during rotation of the workpiece.

1 Workpiece machining device 2 Workpiece 2a Chamfered portion 2b One side surface (surface to be adsorbed)
3, 6, 14 Rotation shaft 4 Workpiece support mechanism 4a X-direction moving stage 4b Y-direction moving stage 4c Z-direction moving stage 4d Motor 5 Grindstone 5a Base disk portion 5b Concave grinding portion 5c Mounting hole 5d Concave portion 5e Arc-shaped portion 5f Straight portion 5g Cross-sectionally rectangular grinding portion 5h Slope portion 7 Grindstone support mechanism
7a Case
7b Rotating bearing part
7c Spindle
7d Flange part
7e Bolt
10: Adsorption member 10a: Thin tip shape 11: Truing grindstone (truer)
12: grooved grindstone 12a: groove 13: grooved grindstone support mechanism 15: temperature adjustment mechanism 16: grindstone 16a: formed groove

Claims (17)

A workpiece machining apparatus for forming a disk-shaped workpiece into a desired cross-sectional shape,
The grinding machine includes a workpiece support mechanism that supports the workpiece, a disk-shaped grinding wheel that is arranged parallel to the workpiece, and a grinding wheel support mechanism that supports the grinding wheel,
the workpiece support mechanism rotates the workpiece, the grindstone support mechanism rotates the grindstone, a rotation axis about which the workpiece is rotated by the workpiece support mechanism and a rotation axis about which the grindstone is rotated by the grindstone support mechanism are parallel to each other,
the workpiece support mechanism has an adsorption member that adsorbs only one side of the workpiece, the adsorption member having a planar shape that is a circle having a radius smaller than the radius of the workpiece, and an outer peripheral portion of the circular adsorption member having a tapered shape that becomes thinner toward the outside,
the grinding wheel has a concave grinding portion on its outer periphery, the cross-sectional shape of the concave grinding portion in a cross section along the rotation axis of the grinding wheel is concave recessed from the outer periphery toward the inner periphery, and has an arc-shaped portion at least at both ends in the thickness direction, and has a straight portion between the arc-shaped portions at both ends, the straight portion having a thickness equal to or greater than the thickness of the workpiece and performing grinding for at least one of reducing the diameter of the workpiece and smoothing the middle portion of the outer periphery of the workpiece in the thickness direction ,
The grindstone and the workpiece can be moved relatively toward or away from each other by the grindstone support mechanism or the workpiece support mechanism,
the grindstone support mechanism or the workpiece support mechanism moves the grindstone relative to the workpiece in accordance with a movement condition calculated based on a radius of curvature of the arc-shaped portion of the grindstone so that a contact portion between the concave grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece;
a radius of curvature of the arc-shaped portion of the grindstone is at least 10 times the thickness of the workpiece so that the arc-shaped portion of the grindstone abuts against the workpiece without generating a substantial gap between the arc-shaped portion and the chamfered portion of the desired cross-sectional shape of the workpiece;
A workpiece machining apparatus characterized in that the arc-shaped portion located on the one side of the workpiece that is adsorbed by the suction member has a length, in a cross section along the rotation axis of the grinding wheel, that is greater than or equal to the length of the chamfered portion on the one side of the workpiece having the desired cross-sectional shape, and is less than the length at which the tangent of the arc-shaped portion abuts against the tapered shape of the suction member when in contact with the end of the one side of the workpiece at a position where it extends at an angle that matches the angle of the tapered shape of the suction member. A workpiece machining apparatus for forming a disk-shaped workpiece into a desired cross-sectional shape,
The grinding machine includes a workpiece support mechanism that supports the workpiece, a disk-shaped grinding wheel that is arranged parallel to the workpiece, and a grinding wheel support mechanism that supports the grinding wheel,
the workpiece support mechanism rotates the workpiece, the grindstone support mechanism rotates the grindstone, a rotation axis about which the workpiece is rotated by the workpiece support mechanism and a rotation axis about which the grindstone is rotated by the grindstone support mechanism are parallel to each other,
the workpiece support mechanism has an adsorption member that adsorbs only one side of the workpiece, the adsorption member having a planar shape that is a circle having a radius smaller than the radius of the workpiece, and an outer peripheral portion of the circular adsorption member having a tapered shape that becomes thinner toward the outside,
the grinding wheel has a concave grinding portion on its outer periphery, the cross-sectional shape of the concave grinding portion in a cross section along the rotation axis of the grinding wheel is concave recessed from the outer periphery toward the inner periphery, and has at least an arc-shaped portion at each end in the thickness direction, and an inclined surface portion located outside the arc-shaped portion in the thickness direction and continuously connected to the arc-shaped portion, and has a straight portion between the arc-shaped portions at each end , the straight portion having a thickness equal to or greater than the thickness of the workpiece, and for grinding to at least one of reduce the diameter of the workpiece and smooth a middle portion of the outer periphery of the workpiece in the thickness direction ,
the inclined surface portion extends along a tangent direction of the arc-shaped portion at a boundary position between the arc-shaped portion and the inclined surface portion, the angle of which coincides with an angle of a chamfer on one surface of the workpiece having the desired cross-sectional shape;
The grindstone and the workpiece can be moved relatively toward or away from each other by the grindstone support mechanism or the workpiece support mechanism,
the grindstone support mechanism or the workpiece support mechanism moves the grindstone relative to the workpiece in accordance with a movement condition calculated based on a radius of curvature of the arc-shaped portion of the grindstone so that a contact portion between the concave grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece;
The radius of curvature of the arc-shaped portion of the grinding wheel is at least 10 times the thickness of the workpiece,
a workpiece machining device, characterized in that the inclined portion located on the one side of the workpiece that is attracted by the suction member has a length that is greater than or equal to the length of the chamfered portion on the one side of the workpiece having the desired cross-sectional shape, in a cross section along the rotation axis of the grinding wheel, and when the angle in which the inclined portion extends with respect to the one side of the workpiece is smaller than the angle that the tapered shape of the suction member forms with respect to the one side of the workpiece, the inclined portion has a length that is less than the length at which the inclined portion abuts the tapered shape of the suction member when in contact with the end of the one side of the workpiece at a position where a tangent to the arc-shaped portion extends at an angle that matches the angle of the tapered shape of the suction member. The workpiece machining device according to claim 1 or 2, wherein the concave grinding portion and a cross-sectionally rectangular grinding portion, the surface of which facing the workpiece is a straight line parallel to the thickness direction of the grinding wheel in a cross section along the rotation axis, are arranged side by side in the thickness direction on the outer periphery of the grinding wheel, and the cross-sectionally rectangular grinding portion of the grinding wheel abuts against the outer periphery of the workpiece before grinding is performed by the concave grinding portion, and the grinding wheel moves from the radial outside to the inside of the workpiece to grind the workpiece so as to reduce the radius of the workpiece. The radius r1 of the attraction member is expressed by the radius r2 of the desired cross-sectional shape of the workpiece and the thickness t of the workpiece, and is expressed as r2-10t≦r1≦r2-5t.
3. The workpiece machining device according to claim 1, wherein an angle θ1 of the tapered shape of the suction member is expressed in terms of an angle θ2 of the chamfered portion of the desired cross-sectional shape of the workpiece, such that θ2-10≦θ1≦θ2+5. The workpiece machining device according to claim 1 or 2, wherein the grindstone support mechanism has a spindle to which the grindstone is directly or indirectly attached, and a rotary bearing part that rotatably supports the spindle, and supports the grindstone so that the center of gravity of the grindstone is located between the attachment position of the grindstone and the rotary bearing part. When grinding the outer periphery on one surface side of the workpiece, the grindstone support mechanism and the workpiece support mechanism rotate the workpiece and the grindstone, while moving the arc-shaped portion of the concave grinding portion of the grindstone in a curved manner relative to the workpiece from the outer periphery end face of the workpiece toward the one surface by an angle calculated in advance in accordance with the movement conditions, and when grinding the outer periphery on the other surface side of the workpiece, while rotating the workpiece and the grindstone, move the arc-shaped portion of the concave grinding portion of the grindstone in a curved manner relative to the workpiece from the outer periphery end face of the workpiece toward the other surface by an angle calculated in advance in accordance with the movement conditions,
When performing rough grinding of the outer periphery of the one surface side or the other surface side of the workpiece, the grindstone support mechanism and the workpiece support mechanism rotate the workpiece and the grindstone, move the arc-shaped portion of the concave grinding portion of the grindstone in a curved manner relative to the workpiece from the outer periphery end face of the workpiece toward the one surface side or the other surface by an angle calculated in advance in accordance with the movement conditions, and then stop the relative movement of the grindstone with respect to the workpiece;
The workpiece processing device of claim 1 or 2, wherein, when performing precise grinding of the outer periphery of the one surface side or the other surface side of the workpiece, the grinding wheel support mechanism and the workpiece support mechanism rotate the workpiece and the grinding wheel, move the arc-shaped portion of the concave grinding portion of the grinding wheel in a curved manner relative to the workpiece from the outer periphery end face of the workpiece toward the one surface side or the other surface by an angle calculated in advance in accordance with the movement conditions, and then move the grinding wheel in a linear manner relative to the workpiece. In addition to the grindstone having the concave grinding portion, the grindstone further includes a disk-shaped grooved grindstone disposed obliquely with respect to a tangent direction of the outer periphery of the workpiece and used for more precise grinding than grinding by the concave grinding portion of the grindstone, and a grooved grindstone support mechanism for supporting the grooved grindstone,
The workpiece machining device according to claim 1 or 2, wherein the grooved grindstone support mechanism rotates the grooved grindstone. Further comprising a truing grindstone that can be attached to the work support mechanism in place of the work,
The truing grindstone is moved relative to the grindstone in accordance with the movement conditions by the grindstone support mechanism or the work support mechanism to form an outer shape,
8. The workpiece machining device according to claim 7, wherein the grooved grindstone is pressed against the truing grindstone so that an outer shape of the truing grindstone is transferred to the groove, thereby forming or shaping the groove. The workpiece processing device according to claim 1 or 2, wherein the workpiece support mechanism has a temperature adjustment mechanism that generates a flow of liquid or gas to keep the temperature of the rotation shaft of the workpiece support mechanism constant. The grinding wheel included in the workpiece processing device according to claim 1 or 2,
A grinding wheel, characterized in that the straight portion has a coarser grinding grain size than the arc-shaped portion, and the arc-shaped portion is used for more precise grinding than grinding by the straight portion. The grindstone included in the workpiece processing device according to claim 3,
A grinding wheel characterized in that the grinding portion having a rectangular cross section has a coarser grinding grain size than the grinding portion having a concave cross section, and the concave grinding portion is used for more precise grinding than grinding by the grinding portion having a rectangular cross section. The grinding wheel included in the workpiece processing device according to claim 1 or 2,
A grinding wheel, characterized in that the arc-shaped portion at one end in the thickness direction and the arc-shaped portion at the other end are individually formed so that the average value of the radius of curvature of each is a desired size. The grinding wheel included in the workpiece processing device according to claim 1 or 2,
a difference between a maximum value and a minimum value of a radius of curvature of the arc-shaped portion at one end in a thickness direction and a difference between a maximum value and a minimum value of a radius of curvature of the arc-shaped portion at the other end are both equal to or smaller than a first predetermined value;
A grinding wheel, characterized in that the difference between the average value of the radius of curvature of the arc-shaped portion at one end in the thickness direction and the average value of the radius of curvature of the arc-shaped portion at the other end is a second predetermined value or less. The grinding wheel included in the workpiece processing device according to claim 1 or 2,
A grinding wheel having a straight or tapered mounting hole extending in the thickness direction. A method for machining a workpiece for forming a disc-shaped workpiece into a desired cross-sectional shape using a grinding wheel having a concave grinding portion on its outer periphery, the concave grinding portion having a cross-sectional shape in a cross section along a rotation axis of the grinding wheel that is concave recessed from the outer periphery toward the inner periphery, the grinding wheel having an arc-shaped portion at least at both ends in a thickness direction, and a straight portion having a thickness equal to or greater than the thickness of the workpiece and performing grinding for at least one of reducing a diameter of the workpiece and smoothing an intermediate portion of the outer periphery of the workpiece in the thickness direction, the method comprising the steps of :
placing the workpiece and the grindstone parallel to each other;
and rotating the grindstone and the workpiece about a rotation axis parallel to the rotation axis of the grindstone, while moving the grindstone relative to the workpiece in accordance with a movement condition calculated based on a radius of curvature of the arc-shaped portion of the grindstone such that a contact portion between the concave grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece,
The step of moving the grindstone relative to the workpiece includes:
While rotating the workpiece , only one side of which is attracted by an attraction member , and the grindstone, the arc-shaped portion of the concave grinding portion of the grindstone is moved in a curved manner relative to the workpiece from the outer peripheral end face of the workpiece toward one side by an angle calculated in advance according to the movement conditions, thereby grinding the outer peripheral portion of the one side of the workpiece to form a chamfered portion of the workpiece having the desired cross-sectional shape ;
Moving the grindstone relative to the workpiece from the one surface side to the other surface side along an outer peripheral end surface of the workpiece;
and rotating the workpiece and the grindstone, and moving the arc-shaped portion of the concave grinding portion of the grindstone in a curved manner from the outer peripheral end face of the workpiece toward the other surface by an angle calculated in advance according to the movement conditions, thereby grinding the outer peripheral portion of the workpiece on the other surface side to form a chamfered portion of the workpiece having the desired cross-sectional shape ,
the planar shape of the attraction member is a circle having a radius smaller than the radius of the workpiece, the outer peripheral portion of the circular attraction member has a tapered shape that becomes thinner toward the outside, and the radius of curvature of the arc-shaped portion of the grindstone is at least 10 times the thickness of the workpiece so that the arc-shaped portion of the grindstone abuts against the workpiece without generating a substantial gap between the arc-shaped portion and the chamfered portion of the desired cross-sectional shape of the workpiece,
the arc-shaped portion located on the one surface side of the workpiece attracted by the attraction member has a length, in a cross section along the rotation axis of the grindstone, that is equal to or longer than the length of the chamfered portion on the one surface side of the workpiece having the desired cross-sectional shape, and is less than a length that abuts against the tapered shape of the attraction member in a state in which the tangent of the arc-shaped portion abuts against the tapered shape of the attraction member in a state in which the tangent of the arc-shaped portion abuts against the end of the one surface side of the workpiece at a position that extends at an angle that coincides with the angle of the tapered shape of the attraction member,
When performing rough grinding of the outer periphery of the one surface side or the other surface side of the workpiece, while rotating the workpiece and the grindstone, the arc-shaped portion of the concave grinding portion of the grindstone is moved in a curved manner relative to the workpiece from the outer periphery end face of the workpiece toward the one surface or the other surface by an angle calculated in advance according to the movement conditions so that the rotation axis of the grindstone and the rotation axis of the workpiece are positioned in the same plane, and then the relative movement of the grindstone with respect to the workpiece is stopped;
A workpiece machining method, characterized in that, when performing precise grinding of the outer periphery of the one surface side or the other surface side of the workpiece, while rotating the workpiece and the grinding wheel, the arc-shaped portion of the concave grinding portion of the grinding wheel is moved curvilinearly relative to the workpiece from the outer periphery end face of the workpiece toward the one surface side or the other surface side by an angle calculated in advance in accordance with the movement conditions so that the rotation axis of the grinding wheel and the rotation axis of the workpiece are positioned in the same plane, and then the grinding wheel is moved linearly relative to the workpiece so that the rotation axis of the grinding wheel and the rotation axis of the workpiece move relatively in a plane extending in a direction intersecting perpendicularly or obliquely to the plane in which the rotation axis of the grinding wheel and the rotation axis of the workpiece were positioned during the curvilinear movement. A method for machining a workpiece for forming a disc-shaped workpiece into a desired cross-sectional shape using a grinding wheel having a concave grinding portion on its outer periphery, the concave grinding portion having a cross-sectional shape in a cross section along a rotation axis of the grinding wheel that is concave recessed from the outer periphery toward the inner periphery, the grinding wheel having an arc-shaped portion at least at both ends in the thickness direction , and a slope portion located outside the arc-shaped portion in the thickness direction and continuously connected to the arc-shaped portion, and a straight portion having a thickness equal to or greater than the thickness of the workpiece and performing grinding for at least one of reducing the diameter of the workpiece and smoothing an intermediate portion of the outer periphery of the workpiece in the thickness direction, the method comprising the steps of:
placing the workpiece and the grindstone parallel to each other;
and rotating the grindstone and the workpiece about a rotation axis parallel to the rotation axis of the grindstone, while moving the grindstone relative to the workpiece in accordance with a movement condition calculated based on a radius of curvature of the arc-shaped portion of the grindstone such that a contact portion between the concave grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece, the movement condition being calculated based on a radius of curvature of the arc-shaped portion of the grindstone.
The step of moving the grindstone relative to the workpiece includes:
While rotating the workpiece , only one side of which is attracted by an attraction member , and the grindstone, the arc-shaped portion of the concave grinding portion of the grindstone is moved in a curved manner relative to the workpiece from the outer peripheral end face of the workpiece toward one side by an angle calculated in advance according to the movement conditions, thereby grinding the outer periphery of the one side of the workpiece to form a chamfered portion of the workpiece having the desired cross-sectional shape ;
Moving the grindstone relative to the workpiece along an outer peripheral end surface of the workpiece from the one surface side to the other surface side;
and rotating the workpiece and the grindstone, and moving the arc-shaped portion of the concave grinding portion of the grindstone in a curved manner from the outer peripheral end face of the workpiece toward the other surface by an angle calculated in advance according to the movement conditions, thereby grinding the outer peripheral portion of the workpiece on the other surface side to form a chamfered portion of the workpiece having the desired cross-sectional shape ,
the planar shape of the attraction member is a circle having a radius smaller than the radius of the workpiece, the outer peripheral portion of the circular attraction member has a tapered shape that becomes thinner toward the outside, and the radius of curvature of the arc-shaped portion of the grindstone is at least 10 times the thickness of the workpiece,
the inclined surface portion extends along a tangent direction of the arc-shaped portion at a boundary position between the arc-shaped portion and the inclined surface portion, the angle of the inclined surface portion coinciding with an angle of the chamfered portion on the one surface side of the workpiece having the desired cross-sectional shape;
the inclined portion located on the one surface side of the workpiece that is attracted by the attraction member has a length that is equal to or longer than the length of the chamfered portion on the one surface side of the workpiece having the desired cross-sectional shape in a cross section along the rotation axis of the grindstone, and when the angle formed by the direction in which the inclined portion extends with respect to the one surface of the workpiece is smaller than the angle formed by the tapered shape of the attraction member with respect to the one surface of the workpiece, the inclined portion has a length that is less than the length at which the inclined portion abuts against the tapered shape of the attraction member in a state in which the inclined portion is in contact with the end portion on the one surface side of the workpiece at a position where a tangent to the arc-shaped portion extends at an angle that coincides with the angle of the tapered shape of the attraction member,
When performing rough grinding of the outer periphery of the one surface side or the other surface side of the workpiece, while rotating the workpiece and the grindstone, the arc-shaped portion of the concave grinding portion of the grindstone is moved in a curved manner relative to the workpiece from the outer periphery end face of the workpiece toward the one surface or the other surface by an angle calculated in advance according to the movement conditions so that the rotation axis of the grindstone and the rotation axis of the workpiece are positioned in the same plane, and then the relative movement of the grindstone with respect to the workpiece is stopped;
A workpiece machining method, characterized in that, when performing precise grinding of the outer periphery of the one surface side or the other surface side of the workpiece, while rotating the workpiece and the grinding wheel, the arc-shaped portion of the concave grinding portion of the grinding wheel is moved curvilinearly relative to the workpiece from the outer periphery end face of the workpiece toward the one surface side or the other surface side by an angle calculated in advance in accordance with the movement conditions so that the rotation axis of the grinding wheel and the rotation axis of the workpiece are positioned in the same plane, and then the grinding wheel is moved linearly relative to the workpiece while maintaining the state in which the rotation axis of the grinding wheel and the rotation axis of the workpiece are positioned within the plane in which the rotation axis of the grinding wheel and the rotation axis of the workpiece were positioned during the curvilinear movement. A method for machining a workpiece for forming a disc-shaped workpiece into a desired cross-sectional shape using a grinding wheel having a concave grinding portion on its outer periphery, the concave grinding portion having a cross-sectional shape in a cross section along a rotation axis of the grinding wheel that is concave recessed from the outer periphery toward the inner periphery, the grinding wheel having an arc-shaped portion at least at both ends in a thickness direction, and a straight portion having a thickness equal to or greater than the thickness of the workpiece and performing grinding for at least one of reducing a diameter of the workpiece and smoothing an intermediate portion of the outer periphery of the workpiece in the thickness direction, the method comprising the steps of :
placing the workpiece and the grindstone parallel to each other;
and rotating the grindstone and the workpiece about a rotation axis parallel to the rotation axis of the grindstone, while moving the grindstone relative to the workpiece in accordance with a movement condition calculated based on a radius of curvature of the arc-shaped portion of the grindstone such that a contact portion between the concave grinding portion and the workpiece moves along the desired cross-sectional shape of the workpiece, the movement condition being calculated based on a radius of curvature of the arc-shaped portion of the grindstone.
The step of moving the grindstone relative to the workpiece includes:
While rotating the workpiece , only one side of which is attracted by an attraction member , and the grindstone, the arc-shaped portion of the concave grinding portion of the grindstone is moved in a curved manner relative to the workpiece from the outer peripheral end face of the workpiece toward one side by an angle calculated in advance according to the movement conditions, thereby grinding the outer periphery of the one side of the workpiece to form a chamfered portion of the workpiece having the desired cross-sectional shape ;
Moving the grindstone relative to the workpiece from the one surface side to the other surface side along an outer peripheral end surface of the workpiece;
and rotating the workpiece and the grindstone, and moving the arc-shaped portion of the concave grinding portion of the grindstone in a curved manner from the outer peripheral end face of the workpiece toward the other surface by an angle calculated in advance according to the movement conditions, thereby grinding the outer peripheral portion of the workpiece on the other surface side to form a chamfered portion of the workpiece having the desired cross-sectional shape ,
the planar shape of the attraction member is a circle having a radius smaller than the radius of the workpiece, the outer peripheral portion of the circular attraction member has a tapered shape that becomes thinner toward the outside, and the radius of curvature of the arc-shaped portion of the grindstone is at least 10 times the thickness of the workpiece so that the arc-shaped portion of the grindstone abuts against the workpiece without generating a substantial gap between the arc-shaped portion and the chamfered portion of the desired cross-sectional shape of the workpiece,
the arc-shaped portion located on the one surface side of the workpiece that is attracted by the attraction member has a length that is equal to or longer than the length of the chamfered portion on the one surface side of the workpiece having the desired cross-sectional shape in a cross section along the rotation axis of the grindstone, and is less than a length that abuts against the tapered shape of the attraction member in a state in which the tangent of the arc-shaped portion abuts against the end of the one surface side of the workpiece at a position where the tangent extends at an angle that coincides with the angle of the tapered shape of the attraction member,
When performing rough grinding of the outer periphery of the one surface side or the other surface side of the workpiece, while rotating the workpiece and the grindstone, the arc-shaped portion of the concave grinding portion of the grindstone is moved in a curved manner relative to the workpiece from the outer periphery end face of the workpiece toward the one surface side or the other surface by an angle calculated in advance according to the movement condition, and then the movement of the grindstone relative to the workpiece is stopped;
When performing precise grinding of the outer periphery of the one surface side of the workpiece, while rotating the workpiece and the grindstone, the arc-shaped portion of the concave grinding portion of the grindstone is moved in a curved manner relative to the workpiece from the outer peripheral end face of the workpiece toward the one surface by an angle calculated in advance according to the movement conditions, taking into account a position error in the thickness direction that occurs when the workpiece rotates, and then the movement is stopped. At a position where the grindstone contacts the slope of the chamfered portion of the one surface side of the workpiece, the rotation speed of the workpiece is slowed down and the workpiece is rotated at least one revolution while adjusting the position in the thickness direction of the workpiece, thereby grinding the one surface side of the workpiece while canceling out the position error during the rotation of the workpiece.
a grinding wheel that is rotated in a direction parallel to the outer periphery of the workpiece and a grinding wheel that is moved in a curved manner relative to the workpiece by an angle calculated in advance in accordance with the movement conditions from the outer periphery end face of the workpiece toward the other surface of the workpiece, based on the outermost position on the other surface side in the thickness direction through which the workpiece passes when rotating, taking into account a positional error in the thickness direction that occurs when the workpiece rotates, and then the movement is stopped.The rotation speed of the workpiece is slowed down and the workpiece is rotated at least one revolution while adjusting the position in the thickness direction of the workpiece at a position where the grinding wheel contacts the slope of the chamfered portion on the other surface side of the workpiece, thereby grinding the other surface side of the workpiece while canceling out the positional error during rotation of the workpiece.

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