Grinding device

Abstract

This invention provides a grinding apparatus that appropriately manages the allowance of the grinding wheel. The grinding apparatus includes: a chuck table for holding a workpiece; a grinding unit for grinding the workpiece held by the chuck table using a grinding wheel fixed to the grinding wheel; a grinding feed mechanism for raising and lowering the grinding unit; a reading unit for reading the thickness of the base of the grinding wheel recorded in a recording medium; a base thickness storage unit for storing the thickness of the base read by the reading unit; and a detection unit that detects the mounting surface of the mounting base and the lower surface of the grinding wheel mounted on the mounting base by lowering the grinding unit via the grinding feed mechanism.

Description

Technical Field

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

[0002] The grinding process of a grinding unit involves rotating the grinding wheel within the grinding unit while simultaneously bringing the grinding tool, arranged in a ring on the lower surface of the grinding wheel's base, into contact with the upper surface of the workpiece held by the chuck's holding surface. During grinding, the grinding unit first descends at high speed towards the workpiece to a height just before the lower surface of the grinding tool contacts the upper surface of the workpiece. Then, the descent speed of the grinding unit is adjusted to a speed suitable for grinding the workpiece, and the grinding unit descends again to grind the workpiece. This shortens the processing time.

[0003] In order to perform grinding of the workpiece, the grinding apparatus needs to identify the height position of the grinding unit when the lower surface of the grinding wheel is in contact with the upper surface of the workpiece. Therefore, as shown in Patent Document 1, before the grinding process is performed, a setup operation is performed to store the height position of the grinding unit, i.e., the origin position, when the holding surface of the chuck table is in contact with the lower surface of the grinding wheel, in the grinding apparatus. Furthermore, the height position of the grinding unit, which is increased according to the thickness of the workpiece from the origin position stored in the grinding apparatus during the setup operation, is identified as the height position of the grinding unit when the lower surface of the grinding wheel is in contact with the upper surface of the workpiece.

[0004] When grinding wheels wear down to a certain extent due to grinding, they must be replaced. Previously, the remaining allowance of the grinding wheel was calculated by subtracting the amount of wear from the wheel after replacement (measured with calipers) from the allowance of the newly replaced wheel. The grinding wheel was replaced when this calculated allowance fell below a predetermined value.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2012-135853

[0006] However, an error can occur between the remaining grinding wheel allowance measured by the operator using calipers or similar measuring tools immediately after replacing the grinding wheel and the actual remaining grinding wheel allowance. Therefore, sometimes grinding continues even when there is no grinding wheel residue, resulting in the workpiece being ground using the grinding wheel's base, causing damage. Alternatively, even if there is actual grinding wheel residue, it may be judged as the grinding wheel being used up, prompting the operator to replace the grinding wheel. In other words, due to the inherent error in measuring the remaining grinding wheel allowance, it is difficult to use the grinding wheel to its full extent. Summary of the Invention

[0007] Therefore, the object of the present invention is to provide a grinding apparatus that can effectively utilize the grinding tool by identifying the remaining material of the grinding tool.

[0008] According to the present invention, a grinding apparatus is provided, comprising: a chuck table for holding a workpiece by means of a holding surface; a grinding unit for mounting a grinding wheel on the lower surface of a base, wherein a grinding tool is arranged in a ring on the lower surface of a base, on a mounting base connected to the lower end of a spindle, and grinding the workpiece by means of the grinding tool; a grinding feed mechanism for moving the grinding unit up and down in a direction perpendicular to the holding surface; a control unit; a reading unit for reading the thickness of the base in a recording medium recording at least the thickness of the base on which the grinding wheel is recorded; a base thickness storage unit for storing the thickness of the base read by the reading unit; and a detection unit for detecting the mounting surface of the mounting base by moving the grinding unit down via the grinding feed mechanism. The control unit includes: a mounting surface height storage unit that stores the height of the grinding unit when the grinding unit is lowered by the grinding feed mechanism and detected by the detection unit on the mounting surface of the mounting base; a grinding wheel lower surface height storage unit that stores the height of the grinding unit when the grinding unit is lowered by the grinding feed mechanism and detected by the detection unit on the lower surface of the grinding wheel after the grinding wheel is mounted on the mounting base; and a grinding wheel allowance calculation unit that calculates the allowance of the grinding wheel 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 grinding wheel lower surface height storage unit.

[0009] In the grinding apparatus of the present invention, the thickness of the base is stored in the base thickness storage section, and the grinding wheel allowance is calculated by subtracting the stored base thickness from the distance from the lower surface of the grinding wheel to the mounting surface of the mounting base. Therefore, the grinding wheel allowance can be properly identified and managed without the need for conventional measurements based on vernier calipers, etc. Furthermore, the grinding wheel allowance can be accurately calculated even when there is a deviation in the base thickness. Additionally, the grinding apparatus can confirm whether there is a difference between the actual allowance of the grinding wheel after a certain amount of grinding has been used and the allowance of the grinding wheel identified by the grinding wheel allowance calculation section. Attached Figure Description

[0010] Figure 1 It is a three-dimensional view showing the entire grinding apparatus.

[0011] Figure 2 This is a cross-sectional view showing the grinding apparatus with the detector positioned below the mounting base.

[0012] Figure 3 This is a cross-sectional view showing the grinding apparatus when the detector is in contact with the lower surface of the mounting base.

[0013] Figure 4 This is a cross-sectional view of the grinding apparatus when the detector is pressed down through the lower surface of the mounting base.

[0014] Figure 5 This is a cross-sectional view of the grinding apparatus with the detector positioned below the grinding wheel.

[0015] Figure 6 This is a cross-sectional view of the grinding apparatus showing the detector in contact with the lower surface of the grinding wheel.

[0016] Figure 7 This is a cross-sectional view of a grinding apparatus showing the detector being pressed down by the lower surface of the grinding wheel.

[0017] Figure 8 This is a cross-sectional view showing a detector with an AE sensor.

[0018] Figure 9 This is a cross-sectional view showing a detector with a spring.

[0019] Label Explanation

[0020] 1: Grinding device; 10: Base; 100: Internal base; 11: Column; 17: Workpiece; 170: Upper surface; 2: Chuck table; 20: Suction unit; 200: Holding surface; 21: Frame; 210: Upper surface; 22: Cover; 23: Fold; 24: Housing; 25: Rotating mechanism; 26: Rotation axis; 27: Suction source; 3: Grinding unit; 30: Spindle; 31: Housing; 32: Spindle motor 33: Motion; 34: Mounting base; 35: Grinding wheel; 36: Rotation axis; 300: Recording medium; 330: Mounting surface; 340: Grinding tool; 341: Base; 3400: Lower surface; 3410: Lower surface; 4: Grinding feed mechanism; 40: Ball screw; 41: Guide rail; 42: Z-axis motor; 43: Lifting plate; 44: Support; 45: Rotation axis; 5: Detection unit; 50 51: Cylinder; 52: Sensor; 53: Overflow valve; 54: Valve; 55: Air source; 56: Signal transmitting unit; 57: Contact; 570: Upper surface; 58: Based cylinder; 59: Spring; 500: Contact surface; 501: Lower surface; 520: Light-emitting part; 521: Light-receiving part; 522: Detection line; 6: Horizontal moving mechanism; 60: Ball screw; 61: Guide rail; 62: Motor; 63: [Missing information - likely related to a device or mechanism] Moving plate; 65: Rotation axis; 70: Reading unit; 71: Base thickness storage unit; 75: Thickness measuring unit; 751: Holding surface height measuring device; 752: Upper surface height measuring device; 8: Control unit; 80: Mounting surface height storage unit; 81: Grinding mold lower surface height storage unit; 82: Grinding mold allowance calculation unit; 90: Height measuring unit; 91: Scale; R: Distance; Z1: First height; Z2: Second height. Detailed Implementation

[0021] 1. Structure of the grinding device

[0022] Figure 1 The grinding apparatus 1 shown is a grinding apparatus that uses the grinding unit 3 to grind the workpiece 17. The structure of the grinding apparatus 1 will be described below.

[0023] like Figure 1 As shown, the grinding device 1 has a base 10 extending along the Y-axis direction.

[0024] A chuck worktable 2 is mounted on the base 10. The chuck worktable 2 has a suction part 20 and a frame 21 that supports the suction part 20. The upper surface of the suction part 20 is a holding surface 200 that holds the workpiece 17. The upper surface 210 of the frame 21 and the holding surface 200 are formed on the same plane.

[0025] The chuck table 2 is supported on a bottomed cylindrical housing 24. Inside the housing 24 is a rotating mechanism 25 connected to the chuck table 2. The rotating mechanism 25 enables the chuck table 2 to rotate about a rotation axis 26 in the Z-axis direction.

[0026] A suction source 27 is connected to the suction part 20. By activating the suction source 27, the attraction force is transmitted to the holding surface 200, which is the upper surface of the suction part 20. For example, when the workpiece 17 is placed on the holding surface 200, the suction source 27 is activated, thereby attracting and holding the workpiece 17 through the holding surface 200.

[0027] An inner base 100 is disposed inside the base 10, and a horizontal moving mechanism 6 is disposed on the inner base 100. The horizontal moving mechanism 6 includes: a ball screw 60 having a rotation axis 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, causing the ball screw 60 to rotate about the rotation axis 65; and a movable plate 63, the nut inside of which is screwed into the ball screw 60, and the bottom of the movable plate 63 slidingly contacting the guide rails 61. A housing 24 is supported on the movable plate 63.

[0028] In the horizontal moving mechanism 6, the ball screw 60 is rotated about the rotation axis 65 by the motor 62, thereby the movable plate 63 moves in the Y-axis direction while being guided by the guide rail 61. Furthermore, as the movable plate 63 moves in the Y-axis direction, the housing 24 supported by the movable plate 63 and the chuck table 2 supported by the housing 24 move together in the Y-axis direction.

[0029] A cover 22 and pleats 23 connected to the cover 22 in a telescopic manner are arranged around the chuck table 2. When the chuck table 2 moves in the Y-axis direction, the cover 22 moves together with the chuck table 2 in the Y-axis direction, and the pleats 23 extend and retract.

[0030] A column 11 is erected on the +Y side of the base 10. A grinding feed mechanism 4 is provided on the -Y side of the column 11 to move the grinding unit 3 up and down in the Z-axis direction, which is perpendicular to the holding surface 200.

[0031] The grinding unit 3 includes: a spindle 30 having a rotation axis 35 in the Z-axis direction; a housing 31 supporting the spindle 30 so that it can rotate; a spindle motor 32 driving the spindle 30 to rotate about the rotation axis 35; a mounting base 33 connected to the lower end of the spindle 30; and a grinding wheel 34 mounted on the lower surface of the mounting base 33 in a detachable manner.

[0032] The grinding wheel 34 has: a base 341; and a plurality of generally cuboid grinding tools 340 arranged in a ring on the lower surface of the base 341. The lower surface 3400 of the grinding tools 340 is the grinding surface that contacts the workpiece 17.

[0033] The spindle 30 is rotated by the spindle motor 32, thereby rotating the mounting base 33 connected to the spindle 30 and the grinding wheel 34 mounted on the lower surface of the mounting base 33 together.

[0034] The grinding feed mechanism 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 causes the ball screw 40 to rotate about the rotation axis 45 in the Z-axis direction; an encoder 92 for detecting the rotation angle of the Z-axis motor 42; 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 support 44 connected to the lifting plate 43 to support the grinding unit 3.

[0035] When the ball screw 40 is driven by the Z-axis motor 42 to rotate around the rotation axis 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 support 44 moves in the Z-axis direction, which is perpendicular to the holding surface 200.

[0036] A recording medium 36 is provided on the side of the base 341 of the grinding wheel 34. The recording medium 36 is, for example, a sticker printed with a barcode such as a one-dimensional barcode, which is affixed to the side of the base 341. The thickness of the base 341 is recorded in the recording medium 36. That is, the recording medium 36 records information including the thickness of the base 341.

[0037] The grinding apparatus 1 has a reading unit 70 that reads the thickness of the base 341 recorded in the recording medium 36. The reading unit 70 is, for example, a barcode reader that reads the aforementioned one-dimensional barcode.

[0038] The grinding apparatus 1 has 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. The 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 therein.

[0039] The grinding apparatus 1 has a control unit 8 that controls each action of the grinding apparatus 1.

[0040] A detection part 5 is provided on the cover 22 and on the side of the chuck table 2, which contacts the lower surface 3400 of the grinding tool 340 and the mounting surface 330 of the mounting base 33 to detect the lower surface 3400 of the grinding tool 340 and the mounting surface 330 of the mounting base 33.

[0041] The detection unit 5 includes: a cylinder 51; a platform 50 arranged such that its lower part is housed in the cylinder 51 and its upper part protrudes upward from the cylinder 51; and a sensor 52 disposed inside the cylinder 51.

[0042] The platform 50 is positioned in the cylinder 51 mounted on the cover 22 so that it can contact the grinding wheel 340 or the base 341 when the grinding unit 3 descends in the -Z direction.

[0043] In this embodiment, sensor 52 is a transmissive photoelectric sensor. For example... Figure 2 As shown, the sensor 52 has a light-emitting part 520 and a light-receiving part 521. When the grinding device 1 is running, the light continuously emitted from the light-emitting part 520 travels straight along the detection line 522 and is received by the light-receiving part 521.

[0044] like Figure 1 As shown, a signal transmitting 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 sent from the signal transmitting unit 56 to the control unit 8.

[0045] like Figure 1 and Figure 2 As shown, the cylinder 51 of the detection unit 5 is connected to the air source 55 via the overflow valve 53 and the valve 54. Air generated by the air source 55 is supplied to the cylinder 51, pressurizing it and thus applying force to the platform 50 in the +Z direction. The platform 50 is in its upper limit position when no pressure is applied from above. When the platform 50 is pressed down from above, pressurizing the air inside the cylinder 51 to a pressure exceeding a predetermined pressure, the overflow valve 53 opens appropriately, venting the air supplied from the air source 55 to the outside of the cylinder 51, thus maintaining a constant pressure inside the cylinder 51.

[0046] like Figure 1 As shown, a height measuring unit 90 is provided on the lifting plate 43, which moves together with the lifting plate 43 and measures the height position of the grinding unit 3 in the Z-axis direction. Additionally, a scale 91 with graduations is provided on the guide rail 41. The height measuring unit 90 reads the value (graduation) of the scale 91, thereby measuring the height position of the grinding unit 3 as it moves in the Z-axis direction via the grinding feed mechanism 4.

[0047] Alternatively, the height position of the grinding unit 3 can be measured based on the height signal (a signal indicating the height position of the grinding unit 3) output from the encoder 92 that detects the rotation angle of the Z-axis motor 42.

[0048] The control unit 8 has a mounting surface height storage unit 80. The mounting surface height storage unit 80 has the 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 mounting surface 330 of the mounting base 33 is detected by the detection unit 5.

[0049] The control unit 8 has a grinding wheel lower surface height storage unit 81. The grinding wheel lower surface height storage unit 81 has the function of storing the height of the grinding unit 3 when the grinding wheel 34 is installed on the mounting base 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.

[0050] The control unit 8 has a grinding wheel allowance calculation unit 82. The grinding wheel allowance calculation unit 82 has the function of calculating the allowance for grinding the grinding wheel 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 grinding wheel lower surface height storage unit 81.

[0051] 2. Operation of the grinding device

[0052] The operation of grinding the workpiece 17 using the grinding apparatus 1 will be described. In this case, the operator or control unit 8 first attracts and holds the workpiece 17 in place. Figure 1 The chuck table 2 shown is on the holding surface 200.

[0053] Then, the control unit 8 positions the chuck table 2 below the grinding unit 3 via the horizontal moving mechanism 6.

[0054] Next, the control unit 8 rotates the chuck table 2 about the rotation axis 26 via the rotation mechanism 25, causing the workpiece 17 held by the holding surface 200 to rotate, and uses the spindle motor 32 to rotate the grinding wheel 340 about the rotation axis 35.

[0055] 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 contacts the upper surface 170 of the workpiece 17. The control unit 8 then lowers the grinding wheel 340 further in the -Z direction from this state. Thus, the workpiece 17 is ground by the grinding wheel 340. When the workpiece 17 is ground to a predetermined thickness, the control unit 8 terminates the grinding process on the workpiece 17.

[0056] Due to this grinding process, the lower surface 3400 of the grinding wheel 340 wears down, and the amount of protrusion (allowance) of the grinding wheel 340 from the lower surface 3410 of the base 341 decreases. Therefore, the grinding wheel 34 is replaced with a new grinding wheel 34 before the allowance of the grinding wheel 340 is exhausted.

[0057] Therefore, in the grinding apparatus 1, the control unit 8 uses the detection unit 5 at appropriate times to identify the remaining amount of grinding wheel 340. This process is also performed when the grinding wheel 34 has been replaced with a new grinding wheel 34.

[0058] The following describes the operation of identifying the remaining amount of the grinding wheel 340 in the grinding apparatus 1.

[0059] In order to identify the remaining material of the grinding wheel 340, the control unit 8 uses the reading unit 70 to read the thickness of the base 341 recorded in the recording medium 36 when the grinding wheel 34 is installed on the mounting base 33. The read thickness of the base 341 is stored in the base thickness storage unit 71.

[0060] Furthermore, when the grinding wheel 34 is not mounted on the mounting base 33, the control unit 8 lowers the grinding unit 3 in the -Z direction via the grinding feed mechanism 4 and uses the detection unit 5 to detect the mounting surface 300 of the mounting base 33 of the grinding unit 3. The control unit 8 then stores the height of the grinding unit 3 when the mounting surface 330 of the mounting base 33 is detected in the mounting surface height storage unit 80.

[0061] Specifically, such as Figure 2 As shown, the control unit 8 first moves the movable plate 63 in the Y-axis direction via the horizontal moving mechanism 6, thereby positioning the contact surface 500 of the stage 50 of the detection unit 5 below the mounting base 33.

[0062] Next, as Figure 3 As shown, the control unit 8 lowers the grinding unit 3 in the -Z direction via the grinding feed mechanism 4, so that the mounting surface 330 of the mounting base 33 contacts the contact surface 500 of the stage 50. In this state, the control unit 8 further lowers the mounting base 33 in the -Z direction via the grinding feed mechanism 4, pressing the stage 50 downward through the mounting surface 330 of the mounting base 33.

[0063] And, as Figure 4 As shown, when the lower surface 501 of the stage 50 is pressed to the position of the detection line 522 of the sensor 52, the light emitted from the light-emitting part 520 of the sensor 52 is blocked by the stage 50 and is no longer received by the light-receiving part 521. At the instant when the light is no longer received by the light-receiving part 521, the signal transmitting part 56 of the detection part 5 sends a detection signal to the control unit 8 indicating that the mounting surface 330 of the mounting base 33 has been detected.

[0064] At this time, in order to prevent the pressure inside the cylinder 51 from rising due to pressing down the stage 50, the pressure is vented by means of the relief valve 53 connected to the inside of the cylinder 51, thereby maintaining a substantially constant pressure. As a result, the force applied from the contact surface 500 of the stage 50 to the mounting surface 330 of the mounting base 33 in the +Z direction remains substantially constant, thus enabling accurate measurement. In addition, when the remaining material of the grinding wheel 340 is not being measured, the air in the cylinder 51 is vented, the stage 50 is lowered to its lowest position, and the contact surface 500 of the stage 50 is positioned lower than the holding surface 200.

[0065] Furthermore, when the control unit 8 receives a detection signal indicating that the mounting surface 330 of the mounting base 33 is in contact with the grinding surface 33, the control unit 8 controls the grinding feed mechanism 4 to stop the descent of the grinding unit 3. In addition, when the control unit 8 receives the detection signal, it identifies the value of the scale 91 read by the height measuring unit 90 as the first height Z1 of the grinding unit 3 and stores it in the mounting surface height storage unit 80.

[0066] Furthermore, the height position measurement of the grinding unit 3 when the mounting surface 330 of the mounting base 33 is detected is performed during spindle unit replacement, etc. That is, it is not necessary to perform it when changing the grinding wheel 34. In addition, in the grinding apparatus 1, the difference between the height of the contact surface 500 of the platform 50 and the height of the holding surface 200 when the lower surface 501 of the platform 50 of the detection unit 5 is pressed to the position of the detection line 522 of the sensor 52 is identified in advance.

[0067] Then, the control unit 8 raises the grinding unit 3 via the grinding feed mechanism 4, moving the grinding wheel 34 away from the stage 50.

[0068] Then, the operator installs the grinding wheel 34 on the mounting base 33. Next, the control unit 8 lowers the grinding unit 3 in the -Z direction via the grinding feed mechanism 4, and uses the detection unit 5 to detect the lower surface 3400 of the grinding wheel 340. Furthermore, the control unit 8 stores the height of the grinding unit 3 when the lower surface 3400 of the grinding wheel 340 is detected in the grinding wheel lower surface height storage unit 81.

[0069] Specifically, such as Figure 5 As shown, the control unit 8 first moves the movable plate 63 in the Y-axis direction via the horizontal moving mechanism 6, thereby positioning the contact surface 500 of the stage 50 of the detection unit 5 below the grinding tool 340.

[0070] Next, as Figure 6 As shown, the control unit 8 lowers the grinding unit 3 in the -Z direction through the grinding feed mechanism 4, so that the lower surface 3400 of the grinding tool 340 contacts the contact surface 500 of the stage 50.

[0071] In this state, the control unit 8 causes the grinding wheel 340 to descend further in the -Z direction via the grinding feed mechanism 4, and presses the stage 50 downward through the lower surface 3400 of the grinding wheel 340.

[0072] And, as Figure 7 As shown, when the lower surface 501 of the stage 50 is pressed to the position of the detection line 522 of the sensor 52, the light emitted from the light-emitting part 520 of the sensor 52 is blocked by the stage 50 and is no longer received by the light-receiving part 521. At the instant when the light is no longer received by the light-receiving part 521, the signal transmitting part 56 of the detection part 5 sends a detection signal to the control unit 8 indicating that the lower surface 3400 of the grinding wheel 340 has been detected.

[0073] Furthermore, when the control unit 8 receives a detection signal indicating that the lower surface 3400 of the grinding wheel 340 is being ground, the control unit 8 controls the grinding feed mechanism 4 to stop the descent of the grinding unit 3. Additionally, upon receiving the detection signal, the control unit 8 identifies the value of the scale 91 read by the height measuring unit 90 as the second height Z2 of the grinding unit 3 and stores it in the grinding wheel lower surface height storage unit 81.

[0074] Next, the grinding wheel allowance calculation unit 82 calculates the difference between the first height Z1 stored in the mounting surface height storage unit 80 and the second height Z2 stored in the grinding wheel lower surface height storage unit 81 as the distance R from the lower surface 3400 of the grinding wheel 340 to the mounting surface 330 of the mounting base 33.

[0075] Then, the grinding wheel allowance calculation unit 82 subtracts the thickness of the base 341 stored in the base thickness storage unit 71 from the difference between the first height Z1 and the second height Z2, which is the distance R from the lower surface 3400 of the grinding wheel 340 to the mounting surface 330 of the mounting base 33, thereby obtaining the allowance of the grinding wheel 340.

[0076] As described above, in the grinding apparatus 1, the thickness of the base 341 is stored in the base thickness storage section 71, and the allowance of the grinding tool 340 is calculated by subtracting the stored thickness of the base 341 from the distance R from the lower surface 3400 of the grinding tool 340 to the mounting surface 330 of the mounting base 33. Therefore, the allowance of the grinding tool can be properly identified without the need for conventional measurements based on vernier calipers, etc. Furthermore, even if there is a deviation in the thickness of the base 341, the allowance of the grinding tool 340 can be calculated accurately. In addition, it is possible to confirm whether there is a difference between the actual allowance of the grinding tool 340 after a certain amount of grinding has been used and the allowance of the grinding tool 340 identified by calculation.

[0077] Additionally, the control unit 8 can display the calculated remaining amount of the grinding wheel 340 on a display (not shown) provided with the grinding apparatus 1. In this case, the operator can easily grasp the remaining amount of the grinding wheel 340 and thus appropriately determine whether the grinding wheel 34 needs to be replaced.

[0078] In addition, the control unit 8 can be configured to issue a warning sound or other notification to the operator that the grinding wheel 34 should be replaced if the calculated allowance of the grinding wheel 340 is less than a specified value.

[0079] In addition, the detection unit 5 can also replace, for example Figure 2 The transmitted photoelectric sensor shown is sensor 52, which has... Figure 8 The AE sensor shown has a contact 57 at the upper end of the stage 50. When using the AE sensor, 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 instant it contacts the upper surface 570 of the contact 57 of the AE sensor. A detection signal indicating that the lower surface 3400 of the grinding wheel 340 has been detected is sent 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 AE sensor contact 57 contacts the lower surface 3400 of the grinding wheel 340. Therefore, the time spent calculating the remaining amount of the grinding wheel 340 can be shortened.

[0080] In addition, such as Figure 9 As shown, the detection unit 5 may include: a base cylinder 58 with an opening at the top to house the stage 50; and a spring 59 surrounded by the base cylinder 58. One end of the spring 59 is connected to the lower surface 501 of the stage 50, and the other end is fixed to the bottom of the inner side of the base cylinder 58. By using the spring 59, force can be applied upward to the stage 50 without equipping the grinding apparatus 1 with a pressure generating mechanism such as an air source 55. Therefore, the overall size of the grinding apparatus 1 can be reduced, and the cost of generating pressure can be reduced.

[0081] In addition, Figure 9 In the structure shown, a proximity sensor can be installed to detect the lower surface 501 of the descending stage 50. Additionally, in Figure 9 In the structure shown, a cylinder 51 of the detection unit 5 is installed at a position that prevents the grinding wheel 340 from contacting the table 50 during grinding. The cylinder 51 is, for example, installed at a position where the detection unit 5 is located... Figure 1 The position shown is offset in the -Y direction.

[0082] In this embodiment, the cylinder 51 of the detection unit 5 is disposed on the cover 22. Alternatively, the cylinder 51 of the detection unit 5 can be disposed on the movable plate 63, so that the cylinder 51 and the platform 50 protrude from the cover 22.

[0083] Furthermore, the recording medium 36 is not limited to the aforementioned one-dimensional barcode; for example, it can be a two-dimensional barcode or an RFID (Radio Frequency Identification) code. Additionally, the recording medium 36 is not limited to being affixed to the side of the base 341 as a sticker; it can also be directly marked on the side of the base 341 using laser marking or the like. The recording medium 36 can also, for example, be printed on the inspection sheet of the grinding wheel 34.

[0084] In addition, when measuring the height of the grinding unit 3 based on the height signal output from the encoder 92, for example, the mounting surface height storage unit 80 and the grinding wheel lower surface height storage unit 81 receive the height signal from the encoder 92 and calculate the height difference accordingly.

[0085] In addition, such as Figure 1 As shown, the grinding apparatus 1 may include a thickness measuring unit 75 for measuring the thickness of the workpiece 17. The thickness measuring unit 75 includes: a holding surface height measuring device 751 for measuring the height of the holding surface 200; and an upper surface height measuring device 752 for measuring the height of the upper surface 170 of the workpiece 17. The thickness measuring unit 75 calculates the thickness of the workpiece 17 by taking the difference between the value of the holding surface height measuring device 751 and the value of the upper surface height measuring device 752.

[0086] The control unit 8 stores the height position of the grinding unit 3 when grinding the workpiece 17 is finished. By subtracting the thickness of the workpiece 17 after grinding from this height position, the control unit 8 identifies the height position of the grinding unit 3 where 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 grinding wheel 340 by subtracting the pre-identified height position of the grinding unit 3 when the mounting surface 330 of the mounting base 33 contacts the holding surface 200 and the thickness of the base 341 of the grinding wheel 34 stored in the base thickness storage unit 71 from this height position. That is, the control unit 8 can identify the remaining amount of grinding wheel 340 by measuring the thickness of the workpiece 17 at the end of grinding.

[0087] In the so-called setting of 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, thereby identifying 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 height position of the grinding unit 3 when the lower surface 3400 of the grinding wheel 340 contacts the holding surface 200 is set by calculating the allowance of the grinding wheel 340.

[0088] Furthermore, during the dressing of 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 plate held by the chuck table 2 or a sub-table (not shown). Therefore, a series of actions can be performed: dressing of the lower surface 3400 of the grinding wheel 340; thickness measurement of the dressing plate based on the thickness measurement unit 75; and identification of the remaining grinding wheel 340 based on the height position of the grinding unit 3 identified by the height position identification of the grinding unit 3 based on the scale 91.

Claims

1. A grinding apparatus, wherein, This grinding device has the following features: A chuck table that holds the workpiece by holding its face; The grinding unit has a grinding wheel with a grinding tool arranged in a ring on the lower surface of the base mounted on a mounting base connected to the lower end of the spindle, and the grinding tool is used to grind the workpiece. The grinding feed mechanism causes the grinding unit to move up and down in a direction perpendicular to the holding surface; Control unit; The reading unit reads the thickness of the base in a recording medium on which at least the thickness of the base of the grinding wheel is recorded; A base thickness storage unit stores the thickness of the base read by the reading unit; as well as The inspection unit, when the grinding wheel is not installed on the mounting base, uses the grinding feed mechanism to lower the grinding unit and inspect the mounting surface of the mounting base. When the grinding wheel is installed on the mounting base, the grinding unit, when lowered by the grinding feed mechanism, inspects the lower surface of the grinding wheel and the grinding tool mounted on the mounting base. The control unit includes: The mounting surface height storage unit stores the height of the grinding unit when the grinding unit is lowered by the grinding feed mechanism and detected by the detection unit at the mounting surface of the mounting base; The grinding wheel lower surface height storage unit stores the height of the grinding unit when the grinding unit is lowered by the grinding feed mechanism after the grinding wheel is installed on the mounting base and the lower surface of the grinding wheel is detected by the detection unit. as well as The grinding wheel allowance calculation unit calculates the allowance of the grinding wheel 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 grinding wheel lower surface height storage unit.

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