JP2022029598A - Grinding method - Google Patents

Abstract

To grind a workpiece to have a uniform thickness.SOLUTION: By performing an in-feed grinding step of, in such a horizontal position relation between a first grinding wheel 310 and a holding surface 211 that a lower surface 312 of the first grinding wheel 310 passes through a center 2000 of an upper surface 210 of a stage 21, bringing the first grinding wheel 310 close to the holding surface 211 to perform in-feed grinding of a workpiece 14 held on the holding surface 211, and a creep-feed grinding step of positioning a second grinding wheel 320 on the horizontally outer side of a position above the holding surface 211, a lower surface 322 of the second grinding wheel 320 being located below an upper surface 140 of the workpiece 14 by a predetermined distance, and moving the second grinding wheel in a creep-feed direction in which the second grinding wheel 320 and holding means 2 are brought relatively closer to perform creep-feed grinding of the workpiece 14 with the lower surface 322 and a side surface 323 of the second grinding wheel 320, the workpiece is ground to have a uniform thickness.SELECTED DRAWING: Figure 1

Description

The present invention relates to a grinding method.

As disclosed in Patent Document 1, a grinding device that grinds a square plate-shaped work held on a holding surface using a grinding wheel uses a grinding wheel so that the annular grinding wheel passes through the center of the plate-shaped work. The plate-shaped work is positioned and rotated around the center of the grinding wheel, and the grinding wheel is moved in a direction approaching the plate-shaped work to grind the plate-shaped work rotating around the center of the plate-shaped work.

During the grinding process of the plate-shaped work, the contact area where the lower surface of the grinding wheel comes into contact with the plate-shaped work is repeatedly increased or decreased. The portion having a large contact area with the plate-shaped work has a larger load on the plate-shaped work and the grinding wheel than the portion having a small contact area. Therefore, the amount of the plate-shaped work that sinks and is ground is reduced. As a result, the plate-shaped work that comes into contact with the grinding wheel has a problem that the portion having a large contact area is thicker than the portion having a small contact area.

JP-A-2015-205358

Therefore, a grinding device that holds a square plate-shaped work on a holding surface and grinds it with a grinding wheel has a problem that the plate-shaped work after grinding has a uniform thickness.

The present invention has a holding means that holds the workpiece on the holding surface and can rotate around the center of the holding surface, and a concentric annular ring having a diameter surrounding the annular first grinding wheel and the first grinding wheel. 2 A grinding means with a grinding wheel mounted on the tip of a spindle, an advancing / retreating mechanism for selectively bringing the first grinding wheel or the second grinding wheel closer to the holding surface, and the holding means and the grinding means relative to each other. A grindstone equipped with a horizontal moving means for moving the machining means in the horizontal direction and a vertical moving means for moving the holding means and the grinding means in a direction relatively perpendicular to the holding surface is used to grind the work piece. A grinding method for grinding, wherein the lower surface of either the first grinding wheel or the second grinding wheel passes through the center of the holding surface, and the grinding wheel is horizontal to the holding surface. Due to the positional relationship, the in-feed grinding step in which the grinding wheel is moved in a direction approaching the holding surface to in-feed grind the workpiece held on the holding surface, and the other not used in the in-feed grinding step. The grinding wheel is positioned outside the horizontal direction from above the holding surface, the lower surface of the grinding wheel is positioned lower than the upper surface of the workpiece by a predetermined distance, and the grinding wheel and the holding means are moved relative to each other in the horizontal direction. This is a method for grinding a workpiece, which comprises a creep feed grinding step of creep feed grinding the workpiece on the lower surface and the side surface of the grinding wheel by approaching the creep feed direction, which is the direction.
It is desirable that the workpiece in the above grinding method is polygonal and the holding surface has a shape that follows the shape of the workpiece.
In the above grinding method, it is desirable that the in-feed grinding step uses the first grinding wheel and the creep feed grinding step uses the second grinding wheel having a diameter larger than that of the first grinding wheel.
In the above-mentioned grinding method, the holding means has a plurality of holding surfaces arranged on the upper surface, and in the in-feed grinding step, the center of the upper surface is positioned so as to pass through the grinding wheel, and the center of the upper surface is used as an axis. It is desirable to rotate the upper surface to grind the workpiece held on each holding surface.
In the above grinding method, the plurality of holding surfaces are arranged side by side in a horizontal direction orthogonal to the creep feed direction, and in the creep feed grinding step, the holding surface is horizontally orthogonal to the creep feed direction. The grinding wheel placed outside the upper surface of the holding means and the holding means are relatively close to each other in the creep feed direction, and the grinding wheel of the grinding wheel is arranged so as not to rotate. It is desirable to grind a plurality of workpieces on the bottom surface and the side surface.
In the above grinding method, the holding surface is a rectangle having a long side and a short side, the long side is extended in the creep feed direction, and a plurality of the holding surfaces are horizontally orthogonal to the creep feed direction. It is desirable that they are arranged in the correct direction.

In the grinding apparatus of the present invention, a quadrangular workpiece can be ground to a uniform thickness by performing creep feed grinding after performing in-feed grinding. In particular, when the workpiece is a rectangular plate-shaped work, the long side of the plate-shaped work is extended in the creep feed direction, and the short side is brought closer to the second grinding wheel during creep feed grinding. The workpiece can be finished to a uniform thickness.

It is a perspective view which shows the whole of a grinding apparatus. It is sectional drawing which shows the grinding means and the holding means. It is a top view which shows the positional relationship between the holding means and grinding means at the time of in-feed grinding. It is a top view which shows the positional relationship between the holding means and grinding means at the time of in-feed grinding. It is a top view which shows the positional relationship between the holding means and grinding means at the time of in-feed grinding. It is a top view which shows the positional relationship between the holding means and a grinding means at the time of creep feed grinding. It is a top view which shows the positional relationship between the holding means and a grinding means at the time of creep feed grinding. It is a top view which shows the positional relationship between the holding means and a grinding means at the time of creep feed grinding. It is a perspective view which shows the whole of a grinding apparatus.

1 Grinding device The grinding device 1 shown in FIG. 1 is a grinding device that grinds a workpiece 14 by using a grinding means 3. The workpiece 14 is, for example, a rectangular parallelepiped thin plate. The grinding device 1 includes a base 10 extending in the Y-axis direction and a column 11 standing on the base 10 on the + Y direction side.

A vertical moving means 4 that supports the grinding means 3 so as to be able to move up and down is arranged on the side surface of the column 11 on the −Y direction side. The vertical moving means 4 has a ball screw 40 having a rotation axis 45 in the Z-axis direction, a pair of guide rails 41 arranged parallel to the ball screw 40, and a Z that rotates the ball screw 40 around the rotation axis 45. It includes a shaft motor 42, an elevating plate 43 in which an internal nut is screwed into a ball screw 40 and a side portion is in sliding contact with a guide rail 41, and a holder 44 connected to the elevating plate 43 to support the grinding means 3.

When the ball screw 40 is driven by the Z-axis motor 42 and the ball screw 40 rotates about the rotation shaft 45, the elevating plate 43 is guided by the guide rail 41 to move up and down in the Z-axis direction and the holder. The grinding means 3 held in the 44 moves in the Z-axis direction.
By moving the grinding means 3 up and down in the Z-axis direction using the vertical moving means 4, the holding means 2 and the grinding means 3 can be moved in a direction relatively perpendicular to the holding surface 211.

The grinding means 3 includes a spindle 38 having a rotating shaft 35 in the Z-axis direction, a housing 39 that rotatably supports the spindle 38, and a spindle motor 30 that rotationally drives the spindle 38 about the rotating shaft 35. There is.
A cylinder 63 is connected to the spindle 38 as shown in FIG. The cylinder 63 includes a large diameter portion 630 and a small diameter portion 631 formed at the lower end of the large diameter portion 630. The first mount 331 is connected to the lower end of the small diameter portion 631. Further, a rod 620 and a disk piston 621 connected to the upper end of the rod 620 are housed inside the large diameter portion 630, and a second mount 332 is connected to the lower end of the rod 620. Further, a guide portion 67 for connecting the lower surface of the large diameter portion 630 and the first mount 331 is disposed, and the second mount 332 is formed with a through hole penetrating the guide portion 67. Has been done.
The first grinding wheel 31 is mounted on the first mount 331. Further, the second grinding wheel 32 is mounted on the second mount 332.

As shown in FIG. 1, the first grinding wheel 31 includes a first wheel base 311 and a plurality of first grinding wheels 310 having a substantially rectangular parallelepiped shape arranged in an annular shape on the lower surface of the first wheel base 311. There is.
The second grinding wheel 32 includes a second wheel base 321 and a plurality of second grinding wheels 320 having a substantially rectangular parallelepiped shape arranged in an annular shape on the lower surface of the second wheel base 321. The ring formed by the plurality of second grinding wheels 320 has a diameter large enough to surround the ring formed by the plurality of first grinding wheels 310. The ring formed by the second grinding wheel 320 is a ring concentric with the first grinding wheel 310.
The particle size of the first grinding wheel 310 and the particle size of the second grinding wheel 320 may be the same or different.
By rotating the spindle 38 using the spindle motor 30, the first grinding wheel 31 and the second grinding wheel 32 are rotated.

The rod 620 and the disk piston 621 shown in FIG. 2 constitute the vertical means 62, and the vertical means 62 can move up and down in the space inside the large diameter portion 630 in the Z-axis direction. The disk piston 621 is connected to the air supply source 60, and a switching control unit 61 is arranged between the disk piston 621 and the air supply source 60. The switching control unit 61 is, for example, a control valve, and has a function of switching whether the air supplied from the air supply source 60 is ejected from above the disk piston 621 or from below the disk piston 621. ..

For example, when the switching control unit 61 is used to switch the air supplied from the air supply source 60 so as to be injected in the + Z direction from below the disk piston 621 and inject air from below the disk piston 621, the disk The piston 621 is urged in the + Z direction by air, and the disk piston 621, the rod 620, and the second mount 332 are integrally raised in the + Z direction while being guided by the guide portion 449. As a result, the second mount 332 rises in the + Z direction, and the first grinding wheel 310 is brought closer to the holding surface 211 than the second grinding wheel 320.
Further, when the switching control unit 61 is used to switch the air supplied from the air supply source 60 so as to be injected in the −Z direction from above the disk piston 621 and inject air from above the disk piston 621, a circle is formed. The disk piston 621 is urged in the −Z direction by air, and the disk piston 621, the rod 620, and the second mount 332 are integrally lowered in the −Z direction while being guided by the guide portion 449. As a result, the second mount 332 descends in the −Z direction, and the second grinding wheel 320 is brought closer to the holding surface 211 than the first grinding wheel 310.
In this way, the air supply source 60, the switching control unit 61, and the vertical means 62 control the relationship between the height positions of the first grinding wheel 310 and the second grinding wheel 320 to control the first grinding wheel 310 or the second grinding wheel 320. It constitutes an advancing / retreating mechanism 6 that selectively brings the grindstone 320 closer to the holding surface 211.

As shown in FIG. 1, the holding means 2 is arranged on the base 10. The holding means 2 is, for example, a chuck table for holding the workpiece 14.
The holding means 2 includes a disk-shaped stage 21 and a frame body 22 that supports the stage 21. On the upper surface 210 of the stage 21, for example, a plurality of (four in FIG. 1) holding surfaces 211 in which the workpiece 14 is held are arranged. The holding surface 211 is formed in a rectangular shape having, for example, a long side 212 extending in the Y-axis direction and a short side 213 extending in the X-axis direction, and is formed in the X-axis direction on the upper surface 210 of the stage 21. They are arranged side by side.

A suction source (not shown) is connected to each holding surface 211. For example, by exerting a suction force using the suction source in a state where the workpiece 14 is placed on the holding surface 211, the generated suction force is transmitted to the holding surface 211 and placed on the holding surface 211. The workpiece 14 is sucked from the holding surface 211. As a result, the workpiece 14 can be sucked and held on the holding surface 211.

An internal base 100 is disposed inside the base 10. A horizontal moving means 5 for moving the holding means 2 in the horizontal direction is arranged on the internal base 100.
The horizontal moving means 5 includes a ball screw 50 having a rotating shaft 55 in the Y-axis direction, a pair of guide rails 51 arranged in parallel with the ball screw 50, and a ball screw connected to the ball screw 50 and centered on the rotating shaft 55. It includes a Y-axis motor 52 that rotates 50, and a movable plate 53 in which a nut at the bottom is screwed into a ball screw 50 and moves in the Y-axis direction along a guide rail 51.
When the ball screw 50 is driven by the Y-axis motor 52 and the ball screw 50 rotates about the rotation axis 55, the movable plate 53 is guided by the guide rail 51 and moves horizontally in the Y-axis direction.

A rotating means 26 for rotating the holding means 2 is arranged on the upper surface 530 of the movable plate 53, and an annular base 23 is arranged around the rotating means 26.
For example, three through holes 230 (two are shown in FIG. 1) are formed at equidistant positions on the same circumference of the base 23, and the base is formed on the upper surface 530 of the movable plate 53. Three support columns 24 (two are shown in FIG. 1) that support the platform 23 are erected. Each through hole 230 is penetrated through each support pillar 24, and the support pillar 24 is fixed to the upper surface 530 of the movable plate 53. Each support pillar 24 has, for example, an expansion / contraction mechanism (not shown), and the inclination of the holding means 2 is adjusted by appropriately raising and lowering each support pillar 24 in the Z-axis direction.

When the movable plate 53 moves in the Y-axis direction, the rotating means 26, the base 23, and the holding means 2 supported by the movable plate 53 move horizontally in the Y-axis direction integrally with the movable plate 53. Will be done.
By horizontally moving the holding means 2 in the Y-axis direction using the horizontal moving means 5, the holding means 2 and the grinding means 3 can be relatively moved in the horizontal direction.

The rotating means 26 includes, for example, a motor (not shown). By operating the motor, the holding means 2 can be rotated about the axis in the Z-axis direction passing through the center 2000 thereof.

A cover 27 and a bellows 28 stretchably connected to the cover 27 are arranged around the holding means 2. For example, when the holding means 2 moves in the Y-axis direction, the cover 27 moves in the Y-axis direction together with the holding means 2, and the bellows 28 expands and contracts.

2 Grinding method (in-feed grinding process)
A method of grinding the workpiece 14 using the grinding device 1 will be described. First, the switching control unit 61 of the advancing / retreating mechanism 6 is operated in advance, and air is supplied from the air supply source 60 to inject air from below the disk piston 621 in the + Z direction to raise the second mount 332. As a result, the second grinding wheel 320 moves in the + Z direction with respect to the first grinding wheel 310, and the first grinding wheel 310 is closer to the holding surface 211 than the second grinding wheel 320.

Then, the workpiece 14 is placed on each of the plurality of holding surfaces 211 of the holding means 2, and the suction source is operated. As a result, the generated suction force is transmitted to the holding surface 211, and the workpiece 14 is sucked and held on the holding surface 211.

Further, the holding means 2 is rotated by using the rotating means 26 to rotate the workpiece 14 held by the holding surface 211, and the first grinding wheel 310 and the second grinding wheel 320 are used by using the spindle motor 30. Keep it rotated.

Next, the holding means 2 is moved in the + Y direction by using the horizontal moving means 5, and the lower surface 312 of the first grinding wheel 310 passes through the center 2000 of the upper surface 210 of the stage 21 as shown in FIG. The workpiece 14 is positioned in.

The vertical moving means 4 is in a state where the workpiece 14 held on the holding surface 211 is rotating about the center 2000 and the first grinding wheel 310 is rotating about the rotation axis 35. Is used to lower the grinding means 3 in the −Z direction. When the first grinding wheel 310 is lowered in the −Z direction to approach the holding surface 211, the lower surface 312 of the first grinding wheel 310 comes into contact with the upper surface 140 of the workpiece 14. While the lower surface 312 of the first grinding wheel 310 is in contact with the upper surface 140 of the workpiece 14, the workpiece 14 is in-feed ground by further lowering the first grinding wheel 310 in the −Z direction. To. 4 and 5 show how the workpiece 14 held on the holding surface 211 comes into contact with the first grinding wheel 310 while rotating around the center 2000 of the upper surface 210.

During in-feed grinding of the workpiece 14, for example, the position on the measurement track 219 which is a circumferential track passing through the measurement surface 218 formed flush with the holding surface 211 on the upper surface 210 of the stage 21. A height gauge or the like (not shown) is positioned on the upper surface 140 of the workpiece 14, the height of the holding surface 211 and the height of the upper surface 140 of the workpiece 14 are measured, and the difference between the two heights is calculated to calculate the difference between the two heights. 14 thicknesses are measured. When the workpiece 14 is ground to a predetermined thickness, the in-feed grinding is finished.

(Creep feed grinding process)
After performing in-feed grinding as described above, the grinding means 3 is raised in the + Z direction by using the vertical moving means 4 shown in FIG. 1, and the first grinding wheel 310 is separated from the workpiece 14. Then, the holding means 2 is moved in the −Y direction by using the horizontal moving means 5, and the first grinding wheel 310 and the second grinding wheel 320 are retracted from above the holding surface 211 to the outside in the horizontal direction.

After that, the second grinding wheel 320 is raised with respect to the first grinding wheel 310 by using the advancing / retreating mechanism 6, so that the second grinding wheel 320 is closer to the holding surface 211 than the first grinding wheel 310. ..

Next, the grinding means 3 is lowered in the −Z direction using the vertical moving means 4, and the lower surface 322 of the second grinding wheel 320 is lowered by a predetermined distance from the upper surface 140 of the workpiece 14. The second grinding wheel 320 is positioned at.

Further, by rotating the holding means 2 by an appropriate angle using the rotating means 26, the four holding surfaces 211 are arranged in the X-axis direction as shown in FIG. 6, and the holding means 2 is in this state. The rotation of the holding means 2 by the rotating means 26 is stopped so as not to rotate. As a result, the four holding surfaces 211 are fixed in a state of being arranged in the X-axis direction.

Then, the holding means 2 is moved in the + Y direction by using the horizontal moving means 5. As a result, the second grinding wheel 320 and the holding means 2 arranged outside the upper surface 210 of the stage 21 approach each other in the creep feed direction (Y-axis direction), which is a relative movement direction in the horizontal direction, and the second grinding wheel 320 is approached. The grinding wheel 320 and the workpiece 14 held on the holding surface 211 approach each other in the Y-axis direction.

When the second grinding wheel 320 and the workpiece 14 held on the holding surface 211 approach each other in the Y-axis direction, the side surface 323 and the lower surface 322 of the second grinding wheel 320 are workpieces as shown in FIG. The workpiece 14 is creep-fed ground in contact with the upper surface 140 of the object 14. As shown in FIG. 8, when the holding means 2 moves in the + Y direction to a horizontal position where the entire surfaces of the four workpieces 14 held on the holding surface 211 are ground, the creep feed grinding is completed.

In the grinding apparatus 1, the rectangular workpiece 14 can be ground to a uniform thickness by performing creep feed grinding after performing in-feed grinding. Further, particularly when the workpiece 14 is a rectangular plate-shaped workpiece, the workpiece 14 is finished to have a uniform thickness by approaching the second grinding wheel 320 from the short side 213 during creep feed grinding. be able to.

In the above grinding method, even if the in-feed grinding of the workpiece 14 is performed using the second grinding wheel 320 and then the creep feed grinding of the workpiece 14 is performed using the first grinding wheel 310. good.

Further, the upper surface 210 of the stage 21 does not have to have a structure in which rectangular holding surfaces 211 are arranged in the same direction. For example, each holding surface 211 may be rectangular and the directions may not be aligned in one direction, or the sizes of the rectangles may be irregular. Further, the shape of each holding surface 211 may be a polygon other than a rectangle, or may be a circle or an ellipse.

The grinding device 1 may include a second holding means 8 shown in FIG. 9 instead of the holding means 2. As shown in FIG. 9, the second holding means 8 includes a disk-shaped suction portion 80 and a frame body 81 that supports the suction portion 80. The upper surface of the suction portion 80 is a holding surface 800 on which the disk-shaped second workpiece 15 is held, and the upper surface 810 of the frame body 81 is formed flush with the holding surface 800.
Further, the suction unit 80 is connected to a suction source (not shown). For example, by operating the suction source with the second workpiece 15 placed on the holding surface 800, the generated suction force is transmitted to the holding surface 800, and the second workpiece 15 is placed on the holding surface 800. Can be sucked and held.

When grinding the second workpiece 15 held by the second holding means 8, first, the first grinding wheel 310 is brought closer to the holding surface 800 than the second grinding wheel 320 by using the advancing / retreating mechanism 6 in advance. The second workpiece 15 is held on the holding surface 800 of the second holding means 8.
Further, the spindle motor 30 is used to rotate the first grinding wheel 310 and the second grinding wheel 320, and the rotating means 26 is used to rotate the second workpiece 15 held by the second holding means 8.
Further, the second holding means 8 is moved in the + Y direction by using the horizontal moving means 5, and the second holding means 8 and the grinding means are made so that the lower surface 312 of the first grinding wheel 310 passes through the center 8000 of the holding surface 800. Adjust the horizontal position relationship with 3.
Then, the grinding means 3 is lowered in the −Z direction using the vertical moving means 4 to bring the first grinding wheel 310 closer to the holding surface 800, and the second grinding wheel 310 is held on the lower surface 312 and the holding surface 800 of the first grinding wheel 310. It is brought into contact with the workpiece 15. As a result, the second workpiece 15 is in-feed ground.

After the in-feed grinding is completed, the grinding means 3 is raised in the + Z direction by using the vertical moving means 4, and the first grinding wheel 310 and the second grinding wheel 320 are separated from the second workpiece 15 in the + Z direction. .. Further, the second workpiece 15 held by the second holding means 8 is moved in the −Y direction by using the horizontal moving means 5, and the second workpiece 15 is moved to the first grinding wheel 310 and the second grinding wheel. Separated from 320 in the −Y direction. As a result, the lower surface 322 of the second grinding wheel 320 is positioned on the outer side in the horizontal direction from above the holding surface 800.

After that, the second grinding wheel 320 is brought closer to the holding surface 800 than the first grinding wheel 310 by using the advancing / retreating mechanism 6, and the grinding means 3 is moved in the −Z direction by using the vertical moving means 4 to perform the second grinding. The height position of the second grinding wheel 320 is adjusted so that the lower surface 322 of the grindstone 320 is lower than the upper surface 150 of the second workpiece 15 by a predetermined distance.

Then, the second workpiece 15 held by the second holding means 8 is moved in the + Y direction by using the horizontal moving means 5, and the second grinding wheel 320 and the second holding means 8 are relatively creep-fed. Bring it closer in the direction. As a result, the lower surface 322 and the side surface 323 of the second grinding wheel 320 come into contact with the upper surface 150 of the second workpiece 15, and the second workpiece 15 is creep-fed ground.

Even if the second workpiece 15 has a disk shape, the second holding means 8 having a holding surface 800 having a shape suitable for the shape is selected, and in-feed grinding and creep-feed grinding are performed to perform the second. The workpiece 15 can be ground to a uniform thickness.

In the above grinding method, after in-feed grinding of the second workpiece 15 is performed using the second grinding wheel 320, creep feed grinding of the second workpiece 15 is performed using the first grinding wheel 310. May be done.

Further, for example, even when a plurality of square-shaped chips are formed on the upper surface 150 of the second workpiece 15, and the chips are sealed with a resin, the resin is similarly in-feed ground and then creeped. The chips can be exposed by feed grinding to form grinding marks in the same direction on the exposed surface of the chips.

1: Grinding device 10: Base 100: Internal base 2: Holding means 21: Stage 210: Top surface of stage 211: Holding surface 212: Long side 213: Short side 22: Frame 220: Top surface of frame 23: Base 230 : Through hole 24: Support pillar 26: Rotating means 27: Cover 28: Bellows 2000: Center 3: Grinding means 30: Spindle 38: Spindle motor 39: Housing 33: Mount 31: First grinding wheel 310: First grinding wheel 311 : 1st wheel base 312: Bottom surface 313: Side surface 32: 2nd grinding wheel 320: 2nd grinding wheel 321 1: 2nd wheel base 322: Bottom surface 323: Side surface 4: Vertical movement means 40: Ball screw 41: Guide rail 42 : Z-axis motor 43: Elevating plate 44: Holder 45: Rotating shaft 5: Horizontal moving means 50: Ball screw 51: Guide rail 52: Y-axis motor 53: Movable plate 530: Upper surface of movable plate 6: Advancing / retreating mechanism 60: Air supply Source 61: Switching control unit 62: Vertical means 620: Rod 621: Disc piston 63: Cylinder 630: Large diameter part 631: Small diameter part 449: Guide part 8: Second holding means 80: Suction part 800: Holding surface 81: Frame 810: Top surface of frame 8000: Center 14: Work piece 140: Top surface of work piece 15: Second work piece 150: Top surface of second work piece

Claims (6)

A holding means that holds the workpiece on the holding surface and can rotate around the center of the holding surface, and a concentric annular second grinding wheel with a diameter that surrounds the annular first grinding wheel and the first grinding wheel. The grinding means mounted on the tip of the spindle, the advancing / retreating mechanism for selectively bringing the first grinding wheel or the second grinding wheel closer to the holding surface, and the holding means and the grinding means relatively horizontally. A grinding method for grinding a workpiece using a grinding device including a horizontal moving means for moving and a vertical moving means for moving the holding means and the grinding means in a direction relatively perpendicular to the holding surface. And,
The grinding wheel has a horizontal position between the holding surface and the grinding wheel so that the lower surface of either the first grinding wheel or the second grinding wheel passes through the center of the holding surface. The in-feed grinding step of in-feed grinding the workpiece held on the holding surface by moving the grindstone downward toward the holding surface.
The other grinding wheel not used in the in-feed grinding step is positioned horizontally outside from above the holding surface, and the lower surface of the grinding wheel is positioned a predetermined distance lower than the upper surface of the workpiece, and the grinding wheel and the holding surface are held. Grinding of a workpiece comprising a creep feed grinding step of creep-feed grinding the workpiece on the lower surface and the side surface of the grinding wheel by bringing the means closer to the creep feed direction which is a relative movement direction in the horizontal direction with each other. Method. The method for grinding a workpiece according to claim 1, wherein the workpiece is polygonal and the holding surface has a shape that follows the shape of the workpiece. In the in-feed grinding process, the first grinding wheel is used.
The grinding method according to claim 1 or 2, wherein in the creep feed grinding step, the second grinding wheel having a diameter larger than that of the first grinding wheel is used. The holding means has a plurality of holding surfaces arranged on the upper surface thereof.
The in-feed grinding step is claimed to position the center of the upper surface so that the grinding wheel passes through, rotate the upper surface around the center of the upper surface, and grind the workpiece held on each holding surface. 1 or the grinding method according to claim 2. The plurality of holding surfaces are arranged side by side in a horizontal direction orthogonal to the creep feed direction.
In the creep feed grinding step, the holding surface is fixed so as not to rotate in a state of being arranged in a horizontal direction orthogonal to the creep feed direction, and the grinding wheel is arranged horizontally outside the upper surface of the holding means. The grinding method according to claim 4, wherein the holding means and the holding means are relatively close to each other in the creep feed direction, and a plurality of workpieces are ground on the lower surface and the side surface of the grinding wheel. The holding surface is a rectangle having a long side and a short side.
The grinding method according to claim 3 or 5, wherein the long side is extended in the creep feed direction and a plurality of the holding surfaces are arranged in a horizontal direction orthogonal to the creep feed direction.

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