Grinding method

Abstract

Provided is a grinding method for grinding a workpiece to a uniform thickness. The following steps are performed: a plunge grinding step in which a first grinding tool (310) is brought into close proximity with a holding surface (211) of a holding unit (2) in a horizontal position relationship of the first grinding tool with the holding surface via a center (2000) of an upper surface (210) of a table (21), and a workpiece (14) held by the holding surface is subjected to plunge grinding by the first grinding tool; and a creep feed grinding step in which a second grinding tool (320) is positioned at a position horizontally outward of the holding surface, a lower surface (322) of the second grinding tool is positioned at a position lower than an upper surface (140) of the workpiece by a prescribed distance, the second grinding tool and the holding unit (2) are moved in a creep feed direction in which they approach each other, and the workpiece is subjected to creep feed grinding by the lower surface (322) and a side surface (323) of the second grinding tool.

Description

Technical Field

[0001] This invention relates to grinding methods. Background Technology

[0002] As disclosed in Patent Document 1, the grinding apparatus uses a grinding wheel to grind a quadrilateral plate-shaped workpiece held by a holding surface. The grinding wheel is positioned in a ring-shaped manner through the center of the plate-shaped workpiece and rotated about the center of the grinding wheel. The grinding wheel is then moved toward the plate-shaped workpiece to grind the plate-shaped workpiece that is rotating about the center of the plate-shaped workpiece.

[0003] In the grinding of plate-shaped workpieces, the contact area between the lower surface of the grinding wheel and the workpiece repeatedly increases and decreases. Furthermore, the portion with a larger contact area experiences a greater load on both the workpiece and the grinding wheel compared to the portion with a smaller contact area. Consequently, the workpiece sinks, and less material is ground. This results in the following problem: the thickness of the portion of the workpiece with the larger contact area is greater than the portion with the smaller contact area.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2015-205358

[0005] Therefore, regarding grinding apparatuses that hold quadrilateral plate-shaped workpieces using a holding surface and grind them using a grinding wheel, there is a problem of ensuring that the ground plate-shaped workpieces have a uniform thickness. Summary of the Invention

[0006] This invention relates to a grinding method that uses a grinding apparatus to grind a workpiece. The grinding apparatus includes: a holding unit that holds the workpiece on a holding surface and is rotatable about the center of the holding surface; a grinding unit that has a first annular grinding wheel and a second concentric annular grinding wheel with a diameter surrounding the first grinding wheel mounted at the front end of a spindle; a retraction mechanism that selectively moves either the first or second grinding wheel closer to the holding surface; a horizontal movement unit that moves the holding unit and the grinding unit relative to each other in a horizontal direction; and a vertical movement unit that moves the holding unit and the grinding unit relative to each other in a direction perpendicular to the holding surface. The grinding method includes the following steps: a plunge grinding step, according to... The lower surface of either the first or the second grinding wheel, through the horizontal position relationship between the grinding wheel and the holding surface (such as the center of the holding surface), moves the grinding wheel closer to the lower surface of the holding surface to perform plunge grinding on the workpiece held by the holding surface; and in the gradual feed grinding process, the other grinding wheel not used in the plunge grinding process is positioned horizontally outward from the upper surface of the holding surface and the lower surface of the grinding wheel is positioned at a predetermined distance lower than the upper surface of the workpiece, so that the grinding wheel and the holding unit approach each other in the relative horizontal movement direction, i.e., the gradual feed direction, and the workpiece is gradually fed using the lower surface and side surface of the grinding wheel.

[0007] Preferably, the workpiece in the above grinding method is a polygon, and the shape of the retaining surface follows the shape of the workpiece.

[0008] In the above grinding method, it is preferable to use the first grinding tool in the plunge grinding process and the second grinding tool with a diameter larger than the first grinding tool in the creep grinding process.

[0009] In the above grinding method, preferably, the holding unit is provided with a plurality of holding surfaces on its upper surface, and the plunge grinding process is positioned such that the grinding tool passes through the center of the upper surface, and the upper surface is rotated about the center of the upper surface as an axis to grind the workpiece held by each of the holding surfaces.

[0010] In the above grinding method, it is preferable that a plurality of holding surfaces are arranged in a horizontal direction perpendicular to the feed direction. In the feed grinding process, the holding surfaces are fixed in a non-rotating manner in a state in which they are arranged in a horizontal direction perpendicular to the feed direction, so that the grinding tool, which is arranged at a position on the outer side of the upper surface of the holding unit in the horizontal direction, is relatively close to the holding unit in the feed direction, and the lower surface and side surface of the grinding tool are used to grind a plurality of workpieces.

[0011] In the above grinding method, it is preferable that the holding surface is a rectangle with a long side and a short side, such that the long side extends in the feed direction, and that a plurality of the holding surfaces are arranged in a horizontal direction perpendicular to the feed direction.

[0012] In the grinding apparatus of the present invention, by performing creep grinding after plunge grinding, a quadrilateral workpiece can be ground to a uniform thickness. In particular, when the workpiece is a rectangular plate-shaped workpiece, by extending the long side of the plate-shaped workpiece in the creep feed direction and approaching the second grinding wheel from the short side during creep grinding, the workpiece can be finished to a uniform thickness. Attached Figure Description

[0013] Figure 1 It is a three-dimensional view showing the entire grinding apparatus.

[0014] Figure 2 This is a cross-sectional view showing the grinding unit and the holding unit.

[0015] Figure 3 It is a top view showing the positional relationship between the holding unit and the grinding unit during plunge grinding.

[0016] Figure 4 It is a top view showing the positional relationship between the holding unit and the grinding unit during plunge grinding.

[0017] Figure 5 It is a top view showing the positional relationship between the holding unit and the grinding unit during plunge grinding.

[0018] Figure 6 It is a top view showing the positional relationship between the holding unit and the grinding unit during creep-feed grinding.

[0019] Figure 7 It is a top view showing the positional relationship between the holding unit and the grinding unit during creep-feed grinding.

[0020] Figure 8 It is a top view showing the positional relationship between the holding unit and the grinding unit during creep-feed grinding.

[0021] Figure 9 It is a three-dimensional view showing the entire grinding apparatus.

[0022] Label Explanation

[0023] 1: Grinding device; 10: Base; 100: Internal base; 2: Holding unit; 21: Stage; 210: Upper surface of stage; 211: Holding surface; 212: Long side; 213: Short side; 22: Frame; 220: Upper surface of frame; 23: Base; 230: Through hole; 24: Support column; 26: Rotating unit; 27: Cover; 28: Fold; 2000: Center; 3: Grinding unit; 30: Spindle; 38: Spindle motor; 39: Housing; 33: Mounting base; 31: First grinding wheel; 310: First grinding tool; 311: First grinding wheel base; 312: Lower surface; 313: Side surface; 32: Second grinding wheel; 320: Second grinding tool; 321: Second grinding wheel base; 322: Lower surface; 323: Side surface; 4: Vertical movement unit ; 40: Ball screw; 41: Guide rail; 42: Z-axis motor; 43: Lifting plate; 44: Holding seat; 45: Rotation axis; 5: Horizontal movement unit; 50: Ball screw; 51: Guide rail; 52: Y-axis motor; 53: Movable plate; 530: Upper surface of movable plate; 6: Forward and backward mechanism; 60: Air supply source; 61: Switching control unit; 62: Upper and lower unit; 620: Rod; 621: Circular plate piston; 63: Cylinder; 630: Large diameter section; 631: Small diameter section; 449: Guide section; 8: Second holding unit; 80: Suction section; 800: Holding surface; 81: Frame; 810: Upper surface of frame; 8000: Center; 14: Workpiece; 140: Upper surface of workpiece; 15: Second workpiece; 150: Upper surface of second workpiece. Detailed Implementation

[0024] 1 Grinding device

[0025] Figure 1 The grinding apparatus 1 shown is a grinding apparatus that uses a grinding unit 3 to grind a workpiece 14. The workpiece 14 is, for example, a rectangular parallelepiped sheet. The grinding apparatus 1 has a base 10 extending along the Y-axis and a column 11 erected on the +Y side of the base 10.

[0026] A vertically moving unit 4, which supports the grinding unit 3 and allows it to be raised and lowered, is provided on the side of the column 11 in the -Y direction. The vertically moving unit 4 includes: 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; a Z-axis motor 42 that rotates the ball screw 40 about the rotation axis 45; a lifting plate 43 with a nut inside that is screwed into the ball screw 40, and the side of the lifting plate 43 slidingly contacting the guide rails 41; and a retaining seat 44 connected to the lifting plate 43 to support the grinding unit 3.

[0027] When the ball screw 40 is driven by the Z-axis motor 42 to rotate around the rotation axis 45, the lifting plate 43 is guided by the guide rail 41 to move up and down in the Z-axis direction, and the grinding unit 3 held by the holding seat 44 moves in the Z-axis direction.

[0028] By using the vertical moving unit 4 to move the grinding unit 3 up and down in the Z-axis direction, the holding unit 2 and the grinding unit 3 can be moved relative to each other in a direction perpendicular to the holding surface 211.

[0029] The grinding unit 3 includes: a spindle 38 having a rotation axis 35 in the Z-axis direction; a housing 39 supporting the spindle 38 so that it can rotate; and a spindle motor 30 driving the spindle 38 to rotate about the rotation axis 35.

[0030] like Figure 2 As shown, a cylinder 63 is connected to the main shaft 38. The cylinder 63 has a large-diameter portion 630 and a small-diameter portion 631 formed at the lower end of the large-diameter portion 630. A first mounting seat 331 is connected to the lower end of the small-diameter portion 631. In addition, a rod 620 and a circular plate piston 621 connected to the upper end of the rod 620 are housed inside the large-diameter portion 630, and a second mounting seat 332 is connected to the lower end of the rod 620. Furthermore, a guide portion 449 is provided between the lower surface of the large-diameter portion 630 and the first mounting seat 331 to connect the two, and a through hole is formed on the second mounting seat 332 for the guide portion 449 to pass through.

[0031] A first grinding wheel 31 is mounted on a first mounting base 331. A second grinding wheel 32 is mounted on a second mounting base 332.

[0032] like Figure 1 As shown, the first grinding wheel 31 has a first grinding wheel base 311 and a plurality of first grinding tools 310 in a generally rectangular shape arranged in a ring on the lower surface of the first grinding wheel base 311.

[0033] The second grinding wheel 32 has a second grinding wheel base 321 and a plurality of second grinding tools 320 arranged in a ring on the lower surface of the second grinding wheel base 321 in a generally rectangular parallelepiped shape. The ring formed by the plurality of second grinding tools 320 has a diameter similar to that of the ring formed by the plurality of first grinding tools 310. Furthermore, the ring formed by the second grinding tools 320 is a concentric ring with the first grinding tools 310.

[0034] The grit size of the first grinding wheel 310 and the grit size of the second grinding wheel 320 can be the same or different.

[0035] The spindle motor 30 rotates the spindle 38, thereby rotating the first grinding wheel 31 and the second grinding wheel 32.

[0036] Figure 2 The rod 620 and the circular piston 621 shown constitute an upper and lower unit 62, which can move up and down along the Z-axis within the space inside the large-diameter portion 630. The circular piston 621 is connected to an air supply source 60, and a switching control unit 61 is disposed between the circular piston 621 and the air supply source 60. The switching control unit 61 is, for example, a control valve, and has the function of switching whether the air supplied from the air supply source 60 is ejected from above or below the circular piston 621.

[0037] For example, when the switching control unit 61 switches the air supply from the air supply source 60 to spray air from below the circular plate piston 621 in the +Z direction, the circular plate piston 621 is forced by the air in the +Z direction. As a result, the circular plate piston 621, rod 620, and second mounting base 332 rise together in the +Z direction while being guided by the guide unit 449. As a result, the second mounting base 332 rises in the +Z direction, and the first grinding wheel 310 is closer to the holding surface 211 than the second grinding wheel 320.

[0038] Furthermore, when the switching control unit 61 switches the air supply from the air supply source 60 to spray air from above the circular plate piston 621 in the -Z direction, the circular plate piston 621 is forced in the -Z direction by the air, causing the circular plate piston 621, rod 620, and second mounting base 332 to descend together in the -Z direction while being guided by the guide unit 449. As a result, the second mounting base 332 descends in the -Z direction, and the second grinding wheel 320 is closer to the holding surface 211 than the first grinding wheel 310.

[0039] Thus, the air supply source 60, the switching control unit 61, and the upper and lower units 62 constitute the advance and retraction mechanism 6, which controls the height relationship between the first grinding wheel 310 and the second grinding wheel 320 so that the first grinding wheel 310 or the second grinding wheel 320 selectively approaches the holding surface 211.

[0040] like Figure 1 As shown, a holding unit 2 is provided on the base 10. The holding unit 2 is, for example, a chuck table for holding the workpiece 14.

[0041] The holding unit 2 has a circular plate-shaped platform 21 and a frame 22 that supports the platform 21. For example, a plurality of holders for holding the workpiece 14 are arranged on the upper surface 210 of the platform 21. Figure 1(There are 4) holding surfaces 211. The holding surfaces 211 are, for example, formed into a rectangular shape having a long side 212 extending along the Y-axis direction and a short side 213 extending along the X-axis direction, and are arranged on the upper surface 210 of the stage 21 along the X-axis direction.

[0042] An attraction source (not shown) is connected to each holding surface 211. For example, when the workpiece 14 is placed on the holding surface 211, the attraction source exerts an attraction force, which is transmitted to the holding surface 211 and attracts the workpiece 14 placed on the holding surface 211. Thus, the workpiece 14 can be attracted and held on the holding surface 211.

[0043] An inner base 100 is provided inside the base 10. A horizontal moving unit 5 is provided on the inner base 100 to move the holding unit 2 in the horizontal direction.

[0044] The horizontal moving unit 5 includes: a ball screw 50 having a rotation axis 55 in the Y-axis direction; a pair of guide rails 51 arranged parallel to the ball screw 50; a Y-axis motor 52 connected to the ball screw 50, causing the ball screw 50 to rotate about the rotation axis 55; and a movable plate 53, the bottom of which is screwed with a nut to the ball screw 50, the movable plate 53 moving along the guide rails 51 in the Y-axis direction.

[0045] When the ball screw 50 is driven by the Y-axis motor 52 to rotate around the rotation axis 55, the movable plate 53 is guided by the guide rail 51 to move horizontally in the Y-axis direction.

[0046] A rotating unit 26 for rotating the holding unit 2 is provided on the upper surface 530 of the movable plate 53, and an annular base 23 is provided around the rotating unit 26.

[0047] For example, three are formed at equal intervals on the same circumference of the base 23 (in... Figure 1 Two through holes 230 are shown in the figure. Three rods are vertically arranged on the upper surface 530 of the movable plate 53. Figure 1 Two support columns 24 are shown to support the base 23. Each through hole 230 is penetrated by a support column 24, which is fixed to the upper surface 530 of the movable plate 53. Each support column 24 has, for example, a telescopic mechanism (not shown), which adjusts the tilt of the holding unit 2 by appropriately raising and lowering the support column 24 in the Z-axis direction.

[0048] When the movable plate 53 moves in the Y-axis direction, the rotating unit 26, the base 23 and the holding unit 2 supported by the movable plate 53 move horizontally in the Y-axis direction together with the movable plate 53.

[0049] By using the horizontal moving unit 5 to move the holding unit 2 horizontally in the Y-axis direction, the holding unit 2 and the grinding unit 3 can be moved relative to each other in the horizontal direction.

[0050] The rotating unit 26 may include, for example, an electric motor (not shown). By operating the electric motor, the holding unit 2 can be rotated about an axis in the Z-axis direction passing through its center 2000.

[0051] A cover 27 and pleats 28 that are telescopically connected to the cover 27 are provided around the retaining unit 2. For example, when the retaining unit 2 moves in the Y-axis direction, the cover 27 moves together with the retaining unit 2 in the Y-axis direction, and the pleats 28 extend and retract.

[0052] 2 Grinding methods

[0053] (Plunge grinding process)

[0054] The method for grinding the workpiece 14 using the grinding apparatus 1 will be described. First, the switching control unit 61 of the advance / retract mechanism 6 is activated in advance, and air is supplied from the air supply source 60. As a result, air is injected from the downward direction of the circular plate piston 621 in the +Z direction, causing the second mounting base 332 to rise. Consequently, the second grinding wheel 320 moves in the +Z direction relative to the first grinding wheel 310, so that the first grinding wheel 310 is closer to the holding surface 211 than the second grinding wheel 320.

[0055] Furthermore, the workpiece 14 is placed on each of the multiple holding surfaces 211 of the holding unit 2, and the attraction source is activated. As a result, the attraction force generated is transmitted to the holding surface 211, attracting and holding the workpiece 14 on the holding surface 211.

[0056] In addition, the workpiece 14 held by the holding surface 211 is rotated by rotating the holding unit 26 in advance, and the first grinding wheel 310 and the second grinding wheel 320 are rotated by the spindle motor 30.

[0057] Next, the horizontal movement unit 5 is used to move the holding unit 2 in the +Y direction, as follows: Figure 3 As shown, the workpiece 14 is positioned at the center 2000 of the upper surface 210 of the stage 21, through the lower surface 312 of the first grinding wheel 310.

[0058] With the workpiece 14 held by the holding surface 211 rotating about the center 2000 and the first grinding wheel 310 rotating about the axis of rotation 35, the grinding unit 3 is lowered in the -Z direction using the vertical movement unit 4. When the first grinding wheel 310 approaches the holding surface 211 by lowering in the -Z direction, the lower surface 312 of the first grinding wheel 310 contacts the upper surface 140 of the workpiece 14. With the lower surface 312 of the first grinding wheel 310 in contact with the upper surface 140 of the workpiece 14, the workpiece 14 is further lowered in the -Z direction to perform plunge grinding. Figure 4 and Figure 5 The diagram shows the case where the workpiece 14 held by the holding surface 211 rotates around the center 2000 of the upper surface 210 and comes into contact with the first grinding tool 310.

[0059] In plunge grinding of the workpiece 14, for example, a height gauge (not shown) is positioned on the upper surface 210 of the stage 21 at a position on the upper surface 140 of the workpiece 14 via a circumferential track, i.e., a measuring track 219, formed on the same plane as the holding surface 211, and 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, thereby measuring the thickness of the workpiece 14. If the workpiece 14 is ground to the specified thickness, the plunge grinding ends.

[0060] (Grinding process with gradual feed)

[0061] After performing plunge grinding as described above, using Figure 1 The vertical moving unit 4 shown causes the grinding unit 3 to rise in the +Z direction, causing the first grinding tool 310 to leave the workpiece 14. Furthermore, the horizontal moving unit 5 moves the holding unit 2 in the -Y direction, causing the first grinding tool 310 and the second grinding tool 320 to retract from above the holding surface 211 to the horizontally outer side.

[0062] Then, the advance / retreat mechanism 6 is used to raise the second grinding wheel 320 relative to the first grinding wheel 310, so that the second grinding wheel 320 is closer to the holding surface 211 than the first grinding wheel 310.

[0063] Next, the grinding unit 3 is lowered in the -Z direction using the vertical movement unit 4, and the second grinding tool 320 is positioned at a height position where the lower surface 322 of the second grinding tool 320 is lower than the upper surface 140 of the workpiece 14 by a predetermined distance.

[0064] Additionally, the rotating unit 26 is used to rotate the holding unit 2 by an appropriate angle, thereby achieving the following: Figure 6As shown, the four holding surfaces 211 are arranged in the X-axis direction. In this state, the rotation of the holding unit 2 based on the rotation unit 26 is stopped so that the holding unit 2 does not rotate. Thus, the four holding surfaces 211 are fixed in the X-axis direction.

[0065] Furthermore, the holding unit 2 is moved in the +Y direction using the horizontal moving unit 5. As a result, the second grinding wheel 320, which is disposed on the outer side of the upper surface 210 of the stage 21, and the holding unit 2 approach each other in the relative moving direction in the horizontal direction, i.e., the feed direction (Y-axis direction), and the workpiece 14 held by the second grinding wheel 320 and the holding surface 211 approach each other in the Y-axis direction.

[0066] When the workpiece 14 held by the second grinding wheel 320 and the retaining surface 211 approaches each other in the Y-axis direction, such as Figure 7 As shown, the side surface 323 and lower surface 322 of the second grinding wheel 320 contact the upper surface 140 of the workpiece 14 to perform slow-feed grinding on the workpiece 14. Figure 8 As shown, when the holding unit 2 moves in the +Y direction to the horizontal position where the entire surface of the four workpieces 14 held by the holding surface 211 is ground, the creep feed grinding ends.

[0067] In the grinding apparatus 1, by performing creep grinding after plunge grinding, the quadrilateral workpiece 14 can be ground to a uniform thickness. In particular, when the workpiece 14 is a rectangular plate-shaped workpiece, by approaching the second grinding wheel 320 from the short side 213 during creep grinding, the workpiece 14 can be finished to a uniform thickness.

[0068] Alternatively, in the above grinding method, after the workpiece 14 is plunge-type ground using the second grinding wheel 320, the workpiece 14 can be fed-through ground using the first grinding wheel 310.

[0069] Furthermore, the upper surface 210 of the stage 21 does not necessarily have to be a structure in which the rectangular holding surfaces 211 are arranged in the same direction. For example, each holding surface 211 may be rectangular, but they may not be arranged in the same direction, and the size of the rectangles may also be inconsistent. In addition, the shape of each holding surface 211 may be a polygon other than a rectangle, or it may be a circle or an ellipse.

[0070] Grinding device 1 can replace holding unit 2 and has Figure 9 The second holding unit 8 is shown. (As shown) Figure 9As shown, the second holding unit 8 has a circular plate-shaped suction part 80 and a frame 81 that supports the suction part 80. The upper surface of the suction part 80 is a holding surface 800 for holding the circular plate-shaped second workpiece 15, and the upper surface 810 of the frame 81 and the holding surface 800 are formed in the same plane.

[0071] Additionally, the suction unit 80 is connected to a suction source (not shown). For example, by activating the suction source while the second workpiece 15 is placed on the holding surface 800, the generated attractive force can be transmitted to the holding surface 800, thereby attracting and holding the second workpiece 15 on the holding surface 800.

[0072] When grinding the second workpiece 15 held in the second holding unit 8, firstly, the advance mechanism 6 is used to bring the first grinding tool 310 closer to the holding surface 800 than the second grinding tool 320, and the second workpiece 15 is held on the holding surface 800 of the second holding unit 8.

[0073] In addition, the first grinding wheel 310 and the second grinding wheel 3200 are rotated in advance using the spindle motor 30, and the second workpiece 15 held by the second holding unit 8 is rotated using the rotation unit 26.

[0074] In addition, the second holding unit 8 is moved in the +Y direction by using the horizontal moving unit 5, and the horizontal position relationship between the second holding unit 8 and the grinding unit 3 is adjusted by the lower surface 312 of the first grinding tool 310 passing through the center 8000 of the holding surface 800.

[0075] Furthermore, the grinding unit 3 is lowered in the -Z direction using the vertical movement unit 4, bringing the first grinding wheel 310 close to the holding surface 800, so that the lower surface 312 of the first grinding wheel 310 comes into contact with the second workpiece 15 held by the holding surface 800. Thus, the second workpiece 15 is subjected to plunge grinding.

[0076] After the plunge grinding is completed, the vertical movement unit 4 is used to raise the grinding unit 3 in the +Z direction, causing the first grinding wheel 310 and the second grinding wheel 320 to move away from the second workpiece 15 in the +Z direction. Meanwhile, the horizontal movement unit 5 is used to move the second workpiece 15 held by the second holding unit 8 in the -Y direction, causing the second workpiece 15 to move away from the first grinding wheel 310 and the second grinding wheel 320 in the -Y direction. This positions the lower surface 322 of the second grinding wheel 320 horizontally outward from above the holding surface 800.

[0077] Then, the advance / retract mechanism 6 is used to bring the second grinding wheel 320 closer to the holding surface 800 than the first grinding wheel 310, and the vertical movement unit 4 is used to move the grinding unit 3 in the -Z direction, adjusting the height position of the second grinding wheel 320 such that the lower surface 322 of the second grinding wheel 320 is lower than the upper surface 150 of the second workpiece 15 by a predetermined distance.

[0078] Furthermore, the horizontal moving unit 5 is used to move the second workpiece 15 held by the second holding unit 8 in the +Y direction, so that the second grinding wheel 320 and the second holding unit 8 are relatively close in the feed 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 perform feed grinding on the second workpiece 15.

[0079] Even if the second workpiece 15 is in the shape of a disc, by selecting the second holding unit 8 with a holding surface 800 that is suitable for the shape and performing plunge grinding and creep grinding, the second workpiece 15 can be ground to a uniform thickness.

[0080] Alternatively, in the above grinding method, after the second workpiece 15 is ground by plunge grinding using the second grinding wheel 320, the second workpiece 15 can be ground by feed grinding using the first grinding wheel 310.

[0081] In addition, for example, if a plurality of quadrilateral chips are formed on the upper surface 150 of the second workpiece 15 and the chips are sealed with resin, the chips can also be exposed by slow feed grinding after the resin is cut-in grinding, thereby forming grinding marks in the same direction on the exposed surface of the chip.

Claims

1. A grinding method, comprising grinding a workpiece using a grinding apparatus, the grinding apparatus comprising: A holding unit that holds the workpiece on a holding surface and is capable of rotating about the center of the holding surface; A grinding unit having a first annular grinding wheel and a second concentric annular grinding wheel with a diameter surrounding the first grinding wheel mounted at the front end of the spindle. An advance / retreat mechanism that selectively brings either the first or the second grinding wheel closer to the holding surface; A horizontal moving unit that moves the holding unit relative to the grinding unit in the horizontal direction; and A vertical moving unit that moves the holding unit relative to the grinding unit in a direction perpendicular to the holding surface. in, The grinding method includes the following steps: In the plunge grinding process, the grinding wheel is moved downward toward the holding surface in such a horizontal position that the lower surface of either the first or the second grinding wheel passes through the center of the holding surface, and the workpiece held by the holding surface is plunged into the surface. as well as In the creep-feed grinding process, the grinding wheel, which is not used in the plunge grinding process, is positioned horizontally outward 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. The grinding wheel and the holding unit move closer together in their relative horizontal direction, i.e., the creep-feed direction. The workpiece is then creep-feed ground using the lower surface and side surface of the grinding wheel. The retaining unit has multiple retaining surfaces arranged on its upper surface. This plunge grinding process positions the grinding wheel through the center of the upper surface, causing the upper surface to rotate about its center as an axis, thereby grinding the workpiece held by each of the retaining surfaces. Multiple retaining surfaces are arranged in a horizontal direction perpendicular to the feed direction. In this feed grinding process, the holding surface is fixed in a non-rotating manner, arranged in a horizontal direction perpendicular to the feed direction, so that the grinding tool, which is positioned horizontally outward from the upper surface of the holding unit, is relatively close to the holding unit in the feed direction, and multiple workpieces are ground using the lower surface and side surface of the grinding tool.

2. The grinding method according to claim 1, wherein, The workpiece is a polygon, and the shape of the retaining face follows the shape of the workpiece.

3. The grinding method according to claim 1 or 2, wherein, In this plunge grinding process, the first grinding tool is used. In this feed grinding process, a second grinding wheel with a diameter larger than the first grinding wheel is used.

4. The grinding method according to claim 1 or 2, wherein, The retaining surface is a rectangle with a long side and a short side. The long side is extended in the feed direction, and the plurality of holding surfaces are arranged in a horizontal direction perpendicular to the feed direction.

5. A grinding method, comprising grinding a workpiece using a grinding apparatus, the grinding apparatus comprising: A holding unit that holds the workpiece on a holding surface and is capable of rotating about the center of the holding surface; A grinding unit having a first annular grinding wheel and a second concentric annular grinding wheel with a diameter surrounding the first grinding wheel mounted at the front end of the spindle. An advance / retreat mechanism that selectively brings either the first or the second grinding wheel closer to the holding surface; A horizontal moving unit that moves the holding unit relative to the grinding unit in the horizontal direction; and A vertical moving unit that moves the holding unit relative to the grinding unit in a direction perpendicular to the holding surface. in, The grinding method includes the following steps: In the plunge grinding process, the grinding wheel is moved downward toward the holding surface in such a horizontal position that the lower surface of either the first or the second grinding wheel passes through the center of the holding surface, and the workpiece held by the holding surface is plunged into the surface. as well as In the creep-feed grinding process, the grinding wheel, which is not used in the plunge grinding process, is positioned horizontally outward 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. The grinding wheel and the holding unit move closer together in their relative horizontal direction, i.e., the creep-feed direction. The workpiece is then creep-feed ground using the lower surface and side surface of the grinding wheel. In this plunge grinding process, the first grinding tool is used. In this feed grinding process, a second grinding wheel with a diameter larger than the first grinding wheel is used. The retaining surface is a rectangle with a long side and a short side. The long side is extended in the feed direction, and the plurality of holding surfaces are arranged in a horizontal direction perpendicular to the feed direction.

6. The grinding method according to claim 5, wherein, The workpiece is a polygon, and the shape of the retaining face follows the shape of the workpiece.

7. The grinding method according to claim 5 or 6, wherein, The retaining unit has multiple retaining surfaces arranged on its upper surface. The plunge grinding process is performed by positioning the grinding tool through the center of the upper surface, rotating the upper surface about its center, and grinding the workpiece held by each of the holding surfaces.

8. The grinding method according to claim 7, wherein, Multiple retaining surfaces are arranged in a horizontal direction perpendicular to the feed direction. In this feed grinding process, the holding surface is fixed in a non-rotating manner, arranged in a horizontal direction perpendicular to the feed direction, so that the grinding tool, which is positioned horizontally outward from the upper surface of the holding unit, is relatively close to the holding unit in the feed direction, and multiple workpieces are ground using the lower surface and side surface of the grinding tool.

Images