Grinding Equipment

Abstract

To appropriately manage a residual amount of a grinding wheel.SOLUTION: A thickness of a base 341 recorded in a recording medium 36 is read out by a read-out part 70, and is stored in a base thickness storage part 71. Subsequently, a height of a grinding unit 3 when the grinding unit 3 is lowered by a grinding feed mechanism 4 and a detection part 5 detects a mounting surface 330 of a mount 33 is stored in a mounting surface height storage part 80, and a height of the grinding unit 3 when a grinding wheel 34 is mounted on the mount 33, then the grinding unit 3 is lowered by the grinding feed mechanism 4 and the detection part 5 detects a lower surface 3400 of a grinding wheel 340 is stored in a wheel lower surface height storage part 81. A residual amount of the grinding wheel 340 is calculated by subtracting the thickness of the base 341 stored in the base thickness storage part 71 from a difference between the height stored in the mounting surface height storage part 80 and the height stored in the grinding wheel lower surface height storage part 81, by a wheel residual amount calculation part 82.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a grinding device. [Background technology]

[0002] The grinding of the workpiece by the grinding device is performed by rotating the grinding wheel provided in the grinding unit and abutting the grinding stone arranged in a ring shape on the lower surface of the base of the grinding wheel against the upper surface of the workpiece held on the holding surface of the chuck table. In the grinding process, the grinding unit is first lowered at high speed toward the workpiece to the height position of the grinding unit just before the lower surface of the grinding stone and the upper surface of the workpiece come into contact, and then the lowering speed of the grinding unit is changed to a speed suitable for grinding the workpiece, and the grinding unit is lowered again to grind the workpiece. This shortens the processing time.

[0003] In order to perform grinding of a workpiece, the height position of the grinding unit when the lower surface of the grinding wheel and the upper surface of the workpiece come into contact must be recognized in advance by the grinding device. Therefore, as shown in Patent Document 1, before performing grinding, a setup operation is performed to store in the grinding device the origin position, which is the height position of the grinding unit where the holding surface of the chuck table and the lower surface of the grinding wheel come into contact. Then, the height position of the grinding unit, which is raised by the thickness of the workpiece from the origin position stored in the grinding device by the setup operation, is recognized as the height position of the grinding unit where the lower surface of the grinding wheel and the upper surface of the workpiece come into contact. When the grinding wheel wears down to a certain amount due to grinding processing, the grinding wheel is replaced. Conventionally, the current remaining amount of the grinding wheel is calculated by subtracting the amount of wear of the grinding wheel worn down by grinding processing from the remaining amount of the grinding wheel immediately after replacement, which is measured with a vernier caliper or the like, and the grinding wheel is replaced when the calculated remaining amount of the grinding wheel falls below a preset value. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-135853 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, there may be an error between the remaining amount of the grinding wheel measured by the operator using a caliper or the like immediately after replacing the grinding wheel and the actual remaining amount of the grinding wheel. Therefore, grinding may be continued even though there is no grinding wheel remaining, and the workpiece may be ground with the base of the grinding wheel, damaging the workpiece. Or, even though there is actually a grinding wheel remaining, the operator may determine that there is no grinding wheel remaining and urge the operator to replace the grinding wheel, and the grinding wheel may be replaced. In other words, due to the error factors involved in measuring the remaining amount of the grinding wheel, it is difficult to use the grinding wheel until it is completely used up. [Means for solving the problem]

[0006] The grinding device of the present invention is a grinding device comprising: a chuck table which holds a workpiece by means of a holding surface; a grinding unit in which a grinding wheel having grinding stones arranged in an annular shape on the underside of a base is mounted on a mount connected to the lower end of a spindle and which grinds the workpiece by the grinding stone; a grinding feed mechanism which raises and lowers the grinding unit in a direction perpendicular to the holding surface; and a control unit, wherein the grinding device comprises a reading unit which reads the thickness of the base of at least the grinding wheel recorded on a recording medium on which the thickness of the base is recorded; a base thickness storage unit which stores the thickness of the base read by the reading unit; The control unit further comprises a detection unit that detects the underside of the grinding wheel of the wheel, and the control unit comprises an attachment surface height memory unit that stores the height of the grinding unit when the grinding unit is lowered by the grinding feed mechanism and the detection unit detects the attachment surface of the mount, a grinding wheel underside height memory unit that stores the height of the grinding unit when the grinding unit is lowered by the grinding feed mechanism and the detection unit detects the underside of the grinding wheel after the grinding wheel is attached to the mount, and a grinding wheel remaining amount calculation unit that calculates the remaining amount of the grinding wheel by subtracting the thickness of the base stored in the base thickness memory unit from the difference between the height stored in the attachment surface height memory unit and the height stored in the grinding wheel underside height memory unit. Effect of the Invention

[0007] In the grinding device of the present invention, the thickness of the base is stored in the base thickness storage unit, and the remaining amount of the grinding wheel is calculated by subtracting the stored thickness of the base from the distance from the bottom surface of the grinding wheel to the mounting surface of the mount. Therefore, measurement using a vernier caliper or the like as in the past is not necessary, and the remaining amount of the grinding wheel can be properly recognized and managed. Furthermore, even if there is variation in the thickness of the base, the remaining amount of the grinding wheel can be calculated accurately. Furthermore, in the grinding device, it is possible to check whether there is any difference between the actual remaining amount of the grinding wheel that has been used to a certain extent and the remaining amount of the grinding wheel calculated and recognized by the grinding wheel remaining amount calculation unit. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a perspective view illustrating an entire grinding device. [Diagram 2] FIG. 2 is a cross-sectional view of the grinding apparatus when a detector is positioned below the mount. [Diagram 3] 11 is a cross-sectional view showing the grinding device when the detector is in contact with the underside of the mount. FIG. [Figure 4] 1 is a cross-sectional view of the grinding device when the detector is being pressed down by the underside of the mount. [Diagram 5] FIG. 2 is a cross-sectional view of the grinding apparatus when the detector is positioned below the grinding wheel. [Figure 6] 4 is a cross-sectional view showing the grinding device when the detector is in contact with the lower surface of the grinding wheel. FIG. [Figure 7] 4 is a cross-sectional view showing the grinding apparatus when the detector is pressed down by the lower surface of the grinding wheel. FIG. [Figure 8] FIG. 1 is a cross-sectional view showing a detector equipped with an AE sensor. [Figure 9] FIG. 13 is a cross-sectional view showing a detector with a spring. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] 1. Grinding Equipment Configuration 1 is a grinding apparatus that grinds a workpiece 17 using a grinding unit 3. The configuration of the grinding apparatus 1 will be described below.

[0010] As shown in FIG. 1, the grinding device 1 includes a base 10 extending in the Y-axis direction.

[0011] A chuck table 2 is disposed on the base 10. The chuck table 2 includes a suction unit 20 and a frame 21 that supports the suction unit 20. The upper surface of the suction unit 20 is a holding surface 200 on which the workpiece 17 is held. The upper surface 210 of the frame 21 is formed flush with the holding surface 200.

[0012] The chuck table 2 is supported by a cylindrical casing 24 with a bottom. A rotation mechanism 25 connected to the chuck table 2 is disposed inside the casing 24. The rotation mechanism 25 can rotate the chuck table 2 about a rotation shaft 26 in the Z-axis direction.

[0013] A suction source 27 is connected to the suction unit 20. By operating the suction source 27, a suction force is transmitted to a holding surface 200, which is the upper surface of the suction unit 20. For example, by operating the suction source 27 with the workpiece 17 placed on the holding surface 200, the workpiece 17 can be sucked and held by the holding surface 200.

[0014] An internal base 100 is disposed inside the base 10, and a horizontal movement mechanism 6 is disposed on the internal base 100. The horizontal movement mechanism 6 includes a ball screw 60 having a rotation shaft 65 in the Y-axis direction, a pair of guide rails 61 disposed parallel to the ball screw 60, a motor 62 connected to the ball screw 60 to rotate the ball screw 60 around the rotation shaft 65, and a movable plate 63 whose internal nut screws into the ball screw 60 and whose bottom part is in sliding contact with the guide rail 61. A casing 24 is supported on the movable plate 63.

[0015] In the horizontal movement mechanism 6, the motor 62 rotates the ball screw 60 about a rotation shaft 65, causing the movable plate 63 to move in the Y-axis direction while being guided by the guide rail 61. As the movable plate 63 moves in the Y-axis direction, the casing 24 supported by the movable plate 63 and the chuck table 2 supported by the casing 24 move integrally in the Y-axis direction.

[0016] A cover 22 and a bellows 23 connected to the cover 22 so as to be freely expandable and contractable are disposed around the chuck table 2. When the chuck table 2 moves in the Y-axis direction, the cover 22 moves in the Y-axis direction together with the chuck table 2, causing the bellows 23 to expand and contract.

[0017] A column 11 is provided upright on the +Y direction side of the base 10. A grinding feed mechanism 4 that moves the grinding unit 3 up and down in the Z-axis direction, which is the direction perpendicular to the holding surface 200, is provided on the side surface on the -Y direction side of the column 11.

[0018] The grinding unit 3 comprises a spindle 30 having a rotation axis 35 in the Z-axis direction, a housing 31 that rotatably supports the spindle 30, a spindle motor 32 that rotates the spindle 30 around the rotation axis 35, a mount 33 connected to the lower end of the spindle 30, and a grinding wheel 34 removably attached to the underside of the mount 33.

[0019] The grinding wheel 34 includes a base 341 and a plurality of grinding stones 340 each having a substantially rectangular parallelepiped shape and arranged in an annular shape on the lower surface of the base 341. A lower surface 3400 of the grinding stone 340 is a grinding surface that comes into contact with the workpiece 17.

[0020] By rotating the spindle 30 using the spindle motor 32, the mount 33 connected to the spindle 30 and the grinding wheel 34 attached to the underside of the mount 33 rotate together.

[0021] The grinding feed mechanism 4 includes a ball screw 40 having a rotating shaft 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 around the rotating shaft 45 in the Z-axis direction, an encoder 92 for detecting the rotation angle of the Z-axis motor 42, a lifting plate 43 whose internal nut is screwed onto the ball screw 40 and whose side is in sliding contact with the guide rail 41, and a holder 44 connected to the lifting plate 43 and supporting the grinding unit 3.

[0022] When the ball screw 40 is driven by the Z-axis motor 42 and rotates around the rotation shaft 45, the lifting plate 43 moves up and down in the Z-axis direction while being guided by the guide rail 41, and the grinding unit 3 held by the holder 44 moves in the Z-axis direction, which is perpendicular to the holding surface 200.

[0023] A recording medium 36 is provided on a side surface of a base 341 of the grinding wheel 34. The recording medium 36 is a sticker on which a barcode such as a one-dimensional code is printed, and is attached to the side surface of the base 341. The thickness of the base 341 is recorded on the recording medium 36. That is, information including information on the thickness of the base 341 is recorded on the recording medium 36.

[0024] The grinding device 1 includes a reading unit 70 that reads the thickness of the base 341 recorded on the recording medium 36. The reading unit 70 is, for example, a barcode reader that reads the one-dimensional code described above.

[0025] The grinding device 1 includes a base thickness storage unit 71 that stores the thickness of the base 341 read by the reading unit 70. The base thickness storage unit 71 is connected to the reading unit 70. Information on the thickness of the base 341 read by the reading unit 70 is transmitted to the base thickness storage unit 71 and stored in the base thickness storage unit 71.

[0026] The grinding apparatus 1 includes a control unit 8 that controls various operations of the grinding apparatus 1.

[0027] A detection unit 5 is disposed above the cover 22 and to the side of the chuck table 2, which detects the underside 3400 of the grinding wheel 340 and the mounting surface 330 of the mount 33 by contacting each of them.

[0028] The detection unit 5 includes a cylinder 51 , a table 50 whose lower portion is accommodated in the cylinder 51 and whose upper portion protrudes upward from the cylinder 51 , and a sensor 52 disposed inside the cylinder 51 .

[0029] The table 50 is mounted on a cylinder 51 disposed on the cover 22 so that the table 50 can come into contact with the grinding wheel 340 or the base 341 when the grinding unit 3 is lowered in the -Z direction.

[0030] In this embodiment, the sensor 52 is a transmission type photoelectric sensor. As shown in Fig. 2, the sensor 52 includes a light emitting unit 520 and a light receiving unit 521. When the grinding device 1 is in operation, light continuously emitted from the light emitting unit 520 travels straight along the detection line 522 and is received by the light receiving unit 521.

[0031] 1, a signal transmission unit 56 is connected to the sensor 52. When the light emitted from the light-emitting unit 520 is no longer received by the light-receiving unit 521, a detection signal is transmitted from the signal transmission unit 56 to the control unit 8.

[0032] As shown in Figs. 1 and 2, the cylinder 51 of the detection unit 5 is connected to an air source 55 via a relief valve 53 and a valve 54. The table 50 is urged in the +Z direction by the cylinder 51, which is pressurized by air generated by the air source 55. The table 50 is located at the upper limit position when no pressing force is applied from above. When the table 50 is pressed from above and the air in the cylinder 51 is pressurized, and the air pressure in the cylinder 51 reaches a predetermined pressure or higher, the relief valve 53 is appropriately opened, and the air supplied from the air source 55 to the inside of the cylinder 51 is exhausted to the space outside the cylinder 51, so that the pressure applied to the inside of the cylinder 51 is kept constant.

[0033] 1, the lift plate 43 is provided with a height measuring unit 90 that moves together with the lift plate 43 and measures the height position of the grinding unit 3 in the Z-axis direction. Also, the guide rail 41 is provided with a scale 91 with graduations. The height measuring unit 90 reads the value (gradations) of the scale 91, thereby measuring the height position of the grinding unit 3 moved in the Z-axis direction by the grinding feed mechanism 4.

[0034] The height position of the grinding unit 3 may be measured based on a height signal (a signal indicating the height position of the grinding unit 3) output from an encoder 92 that detects the rotation angle of the Z-axis motor .

[0035] The control unit 8 includes a mounting surface height storage unit 80. The mounting surface height storage unit 80 has a function of storing the height of the grinding unit 3 when the grinding unit 3 is lowered by the grinding feed mechanism 4 and the detection unit 5 detects the mounting surface 330 of the mount 33.

[0036] The control unit 8 includes a grindstone lower surface height storage unit 81. The grindstone lower surface height storage unit 81 has a function of storing the height of the grinding unit 3 when the grinding wheel 34 is attached to the mount 33, the grinding unit 3 is lowered by the grinding feed mechanism 4, and the detection unit 5 detects the lower surface 3400 of the grinding wheel 340.

[0037] The control unit 8 includes a grindstone remaining amount calculation unit 82. The grindstone remaining amount calculation unit 82 has a function of calculating the remaining amount of the grindstone 340 by subtracting the thickness of the base 341 stored in the base thickness storage unit 71 from the difference between the height stored in the mounting surface height storage unit 80 and the height stored in the grindstone lower surface height storage unit 81.

[0038] 2. Grinding Equipment Operation The following describes the operation when grinding the workpiece 17 by the grinding device 1. First, the operator or the control unit 8 causes the workpiece 17 to be sucked and held on the holding surface 200 of the chuck table 2 shown in FIG.

[0039] Thereafter, the control unit 8 controls the horizontal movement mechanism 6 to position the chuck table 2 below the grinding unit 3 .

[0040] Next, the control unit 8 rotates the chuck table 2 around the rotating shaft 26 using the rotation mechanism 25 to rotate the workpiece 17 held on the holding surface 200, and also rotates the grinding wheel 340 around the rotating shaft 35 using the spindle motor 32.

[0041] In this state, the control unit 8 uses the grinding feed mechanism 4 to lower the grinding unit 3 in the -Z direction. As a result, the lower surface 3400 of the grinding wheel 340 comes into contact with the upper surface 170 of the workpiece 17. From this state, the control unit 8 further lowers the grinding wheel 340 in the -Z direction. As a result, the workpiece 17 is ground by the grinding wheel 340. When the workpiece 17 has been ground to a predetermined thickness, the control unit 8 ends the grinding process of the workpiece 17.

[0042] By such grinding, the lower surface 3400 of the grinding wheel 340 is worn down, and the amount of protrusion (remaining amount) of the grinding wheel 340 from the lower surface 3410 of the base 341 becomes smaller. For this reason, the grinding wheel 34 is replaced with a new one just before the remaining amount of the grinding wheel 340 runs out. Therefore, in the grinding device 1, the control unit 8 performs a process of recognizing the remaining amount of the grinding wheel 340 using the detection unit 5 at an appropriate timing. This process is also performed when the grinding wheel 34 is replaced with a new one. Hereinafter, the operation of the grinding device 1 when recognizing the remaining amount of the grinding wheel 340 will be described.

[0043] In order to recognize the remaining amount of the grinding wheel 340, the control unit 8 uses the reading unit 70 to read the thickness of the base 341 recorded on the recording medium 36 when mounting the grinding wheel 34 on the mount 33. The read thickness of the base 341 is stored in the base thickness storage unit 71.

[0044] Furthermore, in a state in which the grinding wheel 34 is not attached to the mount 33, the control unit 8 causes the grinding unit 3 to move down in the -Z direction by the grinding feed mechanism 4, and detects the attachment surface 300 of the mount 33 of the grinding unit 3 using the detection unit 5. Then, the control unit 8 stores in the attachment surface height memory unit 80 the height of the grinding unit 3 when the attachment surface 330 of the mount 33 is detected.

[0045] Specifically, as shown in FIG. 2, the control unit 8 first causes the horizontal movement mechanism 6 to move the movable plate 63 in the Y-axis direction, thereby positioning the contact surface 500 of the table 50 of the detection unit 5 below the mount 33.

[0046] 3, the control unit 8 causes the grinding unit 3 to descend in the -Z direction by the grinding feed mechanism 4, so that the attachment surface 330 of the mount 33 comes into contact with the contact surface 500 of the table 50. In this state, the control unit 8 causes the grinding feed mechanism 4 to further descend the mount 33 in the -Z direction, so that the attachment surface 330 of the mount 33 presses the table 50 downward.

[0047] 4, when the lower surface 501 of the table 50 is pressed down to the position of the detection line 522 of the sensor 52, the light emitted from the light-emitting unit 520 of the sensor 52 is blocked by the table 50 and is no longer received by the light-receiving unit 521. At the moment when the light-receiving unit 521 no longer receives light, a detection signal indicating that the attachment surface 330 of the mount 33 has been detected is transmitted from the signal transmitting unit 56 of the detection unit 5 to the control unit 8. At this time, in order to prevent the pressure inside the cylinder 51 from increasing due to the table 50 being pushed down, the pressure is maintained at a substantially constant level by exhausting the air via a relief valve 53 connected to the inside of the cylinder 51. This keeps the force in the +Z direction applied from the contact surface 500 of the table 50 to the attachment surface 330 of the mount 33 substantially constant, allowing for good measurement. When the remaining amount of the grinding wheel 340 is not being recognized, the air inside the cylinder 51 is exhausted, the table 50 is lowered to the lowest position, and the contact surface 500 of the table 50 is positioned below the holding surface 200.

[0048] Then, when the control unit 8 receives a detection signal indicating that the attachment surface 330 of the mount 33 has been detected, the control unit 8 controls the grinding feed mechanism 4 to stop the descent of the grinding unit 3. In addition, the control unit 8 recognizes the value of the scale 91 read by the height measuring unit 90 when this detection signal is received as the first height Z1 of the grinding unit 3, and stores it in the attachment surface height memory unit 80. The measurement of the height position of the grinding unit 3 when the attachment surface 330 of the mount 33 is detected is performed when the spindle unit is replaced, etc. In other words, it is not necessary to perform this measurement when replacing the grinding wheel 34. In addition, the grinding apparatus 1 recognizes in advance the difference in height between the contact surface 500 of the table 50 and the height of the holding surface 200 when the lower surface 501 of the table 50 of the detection unit 5 is pressed down to the position of the detection line 522 of the sensor 52.

[0049] Thereafter, the control unit 8 causes the grinding feed mechanism 4 to raise the grinding unit 3 and separate the grinding wheel 34 from the table 50.

[0050] Thereafter, the operator mounts the grinding wheel 34 on the mount 33. Next, the control unit 8 causes the grinding unit 3 to lower in the -Z direction by the grinding feed mechanism 4, and detects the lower surface 3400 of the grinding wheel 340 by using the detection unit 5. Then, the control unit 8 stores in the grinding wheel lower surface height storage unit 81 the height of the grinding unit 3 when the lower surface 3400 of the grinding wheel 340 is detected.

[0051] Specifically, as shown in FIG. 5, the control unit 8 first positions the contact surface 500 of the table 50 of the detection unit 5 below the grinding wheel 340 by moving the movable plate 63 in the Y-axis direction using the horizontal movement mechanism 6.

[0052] Next, the control unit 8 causes the grinding unit 3 to move down in the -Z direction by the grinding feed mechanism 4, so that the lower surface 3400 of the grinding wheel 340 and the contact surface 500 of the table 50 come into contact with each other, as shown in FIG.

[0053] In this state, the control unit 8 causes the grinding wheel 340 to further descend in the -Z direction by the grinding feed mechanism 4, and the lower surface 3400 of the grinding wheel 340 presses the table 50 downward.

[0054] 7, when the lower surface 501 of the table 50 is pressed down to the position of the detection line 522 of the sensor 52, the light emitted from the light-emitting portion 520 of the sensor 52 is blocked by the table 50 and is no longer received by the light-receiving portion 521. At the moment when the light-receiving portion 521 no longer receives light, a detection signal indicating that the lower surface 3400 of the grinding wheel 340 has been detected is transmitted from the signal transmitting portion 56 of the detection portion 5 to the control portion 8.

[0055] Then, when the control unit 8 receives a detection signal indicating that the lower surface 3400 of the grinding wheel 340 has been detected, the control unit 8 controls the grinding feed mechanism 4 to stop the descent of the grinding unit 3. In addition, the control unit 8 recognizes the value of the scale 91 read by the height measuring unit 90 when this detection signal is received as the second height Z2 of the grinding unit 3, and stores it in the grinding wheel lower surface height storage unit 81.

[0056] Next, the grindstone remaining amount calculation unit 82 calculates the difference between the first height Z1 stored in the mounting surface height memory unit 80 and the second height Z2 stored in the grindstone lower surface height memory unit 81 as the distance R from the lower surface 3400 of the grinding wheel 340 to the mounting surface 330 of the mount 33.

[0057] Thereafter, the grinding wheel remaining amount calculation unit 82 determines the remaining amount of the grinding wheel 340 by subtracting the thickness of the base 341 stored in the base thickness memory unit 71 from the difference between the first height Z1 and the second height Z2, i.e., the distance R from the lower surface 3400 of the grinding wheel 340 to the mounting surface 330 of the mount 33.

[0058] As described above, in the grinding device 1, the thickness of the base 341 is stored in the base thickness storage unit 71, and the remaining amount of the grinding wheel 340 is calculated by subtracting the stored thickness of the base 341 from the distance R from the lower surface 3400 of the grinding wheel 340 to the mounting surface 330 of the mount 33. Therefore, the remaining amount of the grinding wheel 340 can be appropriately recognized without the need for measurement using a caliper or the like as in the conventional method. Furthermore, even if there is variation in the thickness of the base 341, the remaining amount of the grinding wheel 340 can be calculated satisfactorily. Furthermore, it is possible to check whether there is any difference between the actual remaining amount of the grinding wheel 340 that has been used to a certain extent and the calculated and recognized remaining amount of the grinding wheel 340.

[0059] The control unit 8 may display the calculated remaining amount of the grinding wheel 340 on a display (not shown) provided in the grinding device 1. In this case, the operator can easily grasp the remaining amount of the grinding wheel 340, and therefore can appropriately determine whether or not the grinding wheel 34 should be replaced. In addition, the control unit 8 may be configured to notify the operator that the grinding wheel 34 should be replaced, for example by sounding an alarm, when the calculated remaining amount of the grinding wheel 340 is smaller than a predetermined value.

[0060] The detection unit 5 may include an AE sensor having a contact 57 on the upper end of the table 50 as shown in FIG. 8, instead of the sensor 52, which is a transmission type photoelectric sensor shown in FIG. 2. When the AE sensor is used, for example, in detecting the lower surface 3400 of the grinding wheel 340, the lower surface 3400 of the grinding wheel 340 is detected at the moment when the lower surface 3400 of the grinding wheel 340 comes into contact with the upper surface 570 of the contact 57 of the AE sensor, and a detection signal indicating that the lower surface 3400 of the grinding wheel 340 has been detected is transmitted from the signal transmission unit 56 of the detection unit 5 to the control unit 8. If the AE sensor is used, it is not necessary to lower the grinding wheel 340 by the grinding feed mechanism 4 after the upper surface 570 of the contact 57 of the AE sensor comes into contact with the lower surface 3400 of the grinding wheel 340. Therefore, the time required to calculate the remaining amount of the grinding wheel 340 can be shortened.

[0061] 9, the detection unit 5 may include a bottomed cylinder 58 with an open top that houses the table 50, and a spring 59 surrounded by the bottomed cylinder 58. One end of the spring 59 is connected to the lower surface 501 of the table 50, and the other end is fixed to the inner bottom of the bottomed cylinder 58. By using the spring 59, it is possible to urge the table 50 upward without providing a pressure generating mechanism such as the air source 55 in the grinding device 1. This makes it possible to reduce the overall size of the grinding device 1 and reduce the cost of generating pressure.

[0062] 9, a proximity sensor may be provided to detect the lower surface 501 of the lowered table 50. In the configuration shown in Fig. 9, the cylinder 51 of the detection unit 5 is disposed at a position where the grinding wheel 340 can be prevented from contacting the table 50 during grinding. The cylinder 51 is disposed, for example, at a position shifted in the -Y direction from the position shown in Fig. 1. In this embodiment, the cylinder 51 of the detection unit 5 is disposed on the cover 22. In this regard, the cylinder 51 of the detection unit 5 may be disposed on the movable plate 63, and the cylinder 51 and the table 50 may protrude from the cover 22.

[0063] The recording medium 36 is not limited to the one-dimensional code described above, and may be, for example, a two-dimensional code or an RFID. The recording medium 36 is not limited to a sticker attached to the side surface of the base 341, and may be directly written on the side surface of the base 341 by laser marking or the like. The recording medium 36 may be printed on the inspection sheet of the grinding wheel 34, for example.

[0064] In addition, when the height of the grinding unit 3 is measured based on the height signal output from the encoder 92, for example, the height signal from the encoder 92 is received by the mounting surface height memory unit 80 and the grinding wheel bottom surface height memory unit 81, and the height difference is calculated based on that. 1, the grinding apparatus 1 may include a thickness measuring unit 75 that measures the thickness of the workpiece 17. The thickness measuring unit 75 includes a holding surface height measuring device 751 that measures the height of the holding surface 200, and an upper surface height measuring device 752 that measures the height of the upper surface 170 of the workpiece 17, and calculates the difference between the value of the holding surface height measuring device 751 and the value of the upper surface height measuring device 752 as the thickness of the workpiece 17. The control unit 8 stores the height position of the grinding unit 3 when grinding of the workpiece 17 is finished, and by subtracting the thickness of the workpiece 17 after grinding from that height position, it recognizes the height position of the grinding unit 3 at which the lower surface 3400 of the grinding wheel 340 contacts the holding surface 200. For example, the control unit 8 can obtain the remaining amount of the grinding wheel 340 by subtracting from this height position the height position of the grinding unit 3 when the attachment surface 330 of the mount 33 contacts the holding surface 200, which has been recognized in advance, and the thickness of the base 341 of the grinding wheel 34, which is stored in the base thickness storage unit 71. That is, the control unit 8 can measure the thickness of the workpiece 17 when grinding is completed, and recognize the remaining amount of the grinding wheel 340.

[0065] In so-called setup, which sets the origin of the grinding wheel 340 when the grinding device 1 grinds the workpiece 17, the grinding unit 3 is lowered by the grinding feed mechanism 4 to recognize the height position of the grinding unit 3 when the grinding wheel 340 contacts the holding surface 200 of the chuck table 2. In this embodiment, the remaining amount of the grinding wheel 340 is calculated, thereby completing the setup which recognizes the height position of the grinding unit 3 at which the lower surface 3400 of the grinding wheel 340 contacts the holding surface 200.

[0066] Furthermore, when dressing the grinding wheel 340, the grinding unit 3 is lowered by the grinding feed mechanism 4, thereby bringing the lower surface 3400 of the grinding wheel 340 into contact with the dressing board held on the chuck table 2 or a sub-table (not shown). Therefore, the dressing of the lower surface 3400 of the grinding wheel 340, the thickness measurement of the dressing board by the thickness measurement unit 75, and the recognition of the remaining amount of the grinding wheel 340 using the height position of the grinding unit 3 recognized by the scale 91 can be performed as a series of operations. [Explanation of symbols]

[0067] 1: Grinding device 10: Base 100: Internal base 11: Column 17: Workpiece 170: Top surface 2: Chuck table 20: Suction part 200: Holding surface 21: Frame body 210: Top surface 22: Cover 23: Bellows 24: Casing 25: Rotation mechanism 26: Rotating shaft 27: Suction source 3: Grinding unit 30: Spindle 31: Housing 32: Spindle motor 33: mount; 34: grinding wheel; 35: rotating shaft; 36: recording medium 300: Mounting surface 330: Mounting surface 340: Grinding wheel 341: Base 3400: Bottom surface 3410: Bottom surface 4: Grinding feed mechanism 40: Ball screw 41: Guide rail 42: Z-axis motor 43: Lifting plate 44: Holder 45: Rotating shaft 5: Detector 50: Table 51: Cylinder 52: Sensor 53: Relief valve 54: Valve 55: Air source 56: Signal transmitter 57: Contact 570: Top surface 58: Bottomed tube 59: Spring 500: Contact surface 501: Bottom surface 520: Light emitting part 521: Light receiving unit 522: Detection line 6: Horizontal movement mechanism 60: Ball screw 61: Guide rail 62: Motor 63: Movable plate 65: Rotating shaft 70: Reading section 71: Base thickness storage section 75: Thickness measurement unit 751: Holding surface height measurement device 752: Top surface height measurement device 8: Control unit 80: Mounting surface height storage unit 81: Grindstone lower surface height storage unit 82: Grindstone remaining amount calculation section 90: Height measurement unit 91: Scale R: Distance Z1: First height Z2: Second height

Claims

[Claim 1] a chuck table that holds the workpiece by a holding surface; a grinding unit in which a grinding wheel having grinding stones arranged in an annular shape on the underside of a base is attached to a mount connected to the lower end of a spindle, and which grinds a workpiece with the grinding stones; a grinding feed mechanism that raises and lowers the grinding unit in a direction perpendicular to the holding surface; A control unit; A grinding apparatus comprising: a reading unit that reads at least the thickness of the base of the grinding wheel recorded on a recording medium on which the thickness of the base is recorded; a base thickness storage unit that stores the thickness of the base read by the reading unit; a detection unit that lowers the grinding unit by the grinding feed mechanism and detects the mounting surface of the mount and the lower surface of the grinding stone of the grinding wheel mounted on the mount; Further equipped with The control unit a mounting surface height storage unit that stores a height of the grinding unit when the grinding unit is lowered by the grinding feed mechanism and the detection unit detects the mounting surface of the mount; a grinding wheel lower surface height storage unit that stores the height of the grinding unit when the grinding wheel is attached to the mount, the grinding unit is lowered by the grinding feed mechanism, and the detection unit detects the lower surface of the grinding wheel; a grindstone remaining amount calculation unit that calculates the remaining amount of the grindstone by subtracting the thickness of the base stored in the base thickness storage unit from the difference between the height stored in the mounting surface height storage unit and the height stored in the grindstone lower surface height storage unit; A grinding device comprising:

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