JP2018167367A - Grinding device - Google Patents

Abstract

To prevent the occurrence of breakage of a plate-like work and grinding failure even when sucking and holding the plate-like work having warp by a holding table.SOLUTION: A grinding device 1 comprises: a central communication pipe 20 communicating a central sucking part 110 of a holding table 10 with a sucking source 6; an outer periphery communication pipe 21 communicating an outer periphery sucking part 111 of the holding table 10 with the sucking source 6; a pressure gage 23b measuring negative pressure in the outer periphery communication pipe 21; and a recognition part 24 for recognizing that an outer periphery part Wc of the plate-like work W held by the holding table 10 is in a state of floating up from a holding surface 11a when a negative pressure value in the outer periphery communication pipe 21, measured with the pressure gage 23b becomes larger than a previously set negative pressure value. With this, even when there is warp in the outer periphery part Wc of the plate-like work W, the recognition part 24 can recognize whether the outer periphery part Wc of the plate-like work W floats up from the holding surface 11a or not so as to prevent the occurrence of breakage of the plate-like work W and grinding failure.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a grinding apparatus including a holding table that sucks and holds a plate-like workpiece.

  A processing apparatus such as a grinding apparatus includes a holding table for sucking and holding a plate-like workpiece. The holding table includes at least a porous plate having a holding surface for sucking and holding a plate-like workpiece on the upper surface, and a frame body that houses the porous plate. The frame is formed with a suction path that allows the holding surface and the suction source to communicate with each other, and the plate-like workpiece is sucked and held by exerting a suction action on the holding surface through the suction path.

  When warping occurs in a plate-like workpiece, negative pressure leaks from the part that floats from the holding surface of the holding table even if it tries to suck and hold the plate-like workpiece with the holding table, and the plate-like workpiece cannot be sucked and held. There is. For example, in Patent Document 1 below, even if a plate-like workpiece having warpage is held by sucking and holding the plate-like workpiece with a holding table via an adhesive tape having a larger area than the holding surface of the holding table, the holding surface A method for making it possible to suck and hold by using this is proposed.

JP 2013-93383 A

  However, since the method as described above is intended to prevent the suction force of the holding table from being reduced, regarding the countermeasure when the suction force is reduced on the holding surface that should be in close contact with the outer peripheral portion of the plate-like workpiece. Not specifically assumed. Therefore, when the suction force of the holding table is reduced during the grinding process, there is a problem that a plate-like workpiece having a warp in the outer peripheral portion blows away from the holding table. In addition, even if the plate-shaped workpiece does not blow off from the holding table, there is a problem that the thickness of the plate-shaped workpiece after grinding is not uniform because the outer peripheral portion of the plate-shaped workpiece is lifted from the holding surface.

  The present invention has been made in view of the above circumstances, and even when a plate-like workpiece having warpage is sucked and held by a holding table, the plate-like workpiece can be prevented from being broken or poorly ground. The purpose is to be.

  The present invention includes a holding table having a holding surface for sucking and holding a plate-like workpiece, a grinding means for grinding the plate-like workpiece held by the holding table with a grinding wheel, and the grinding means approaching the holding table. A holding device, wherein the holding table includes a central suction part, at least one annular outer peripheral suction part surrounding the outer periphery of the central suction part, and the center. An at least one annular partition that partitions the suction portion and the outer peripheral suction portion, and the grinding device includes a central communication pipe that communicates the central suction portion with a suction source, and the outer peripheral suction portion. An outer peripheral communication pipe that communicates with the suction source, a pressure gauge that measures the negative pressure in the outer peripheral communication pipe, and a negative pressure value measured by the pressure gauge in the outer peripheral communication pipe that is greater than a preset negative pressure value The holding table holds That the outer peripheral portion of the plate workpiece is provided with a recognizing section to be a floating state from the holding surface.

  Further, the present invention provides the grinding feed means when the recognition unit recognizes the lifting of the outer peripheral portion of the plate-like workpiece from the holding surface before grinding the plate-like workpiece held by the holding table with the grinding wheel. During the grinding of the plate-like workpiece held by the holding table with the grinding wheel, when the recognition unit recognizes the lifting of the outer peripheral portion of the plate-like workpiece from the holding surface, the grinding feed by the grinding feed means is performed. The negative pressure value measured by the pressure gauge is set in advance by stopping or moving the grinding surface of the grinding wheel away from the upper surface of the plate-like workpiece held by the holding table. A control unit for controlling the grinding wheel to move in a direction approaching the upper surface of the plate-like workpiece held by the holding table by the grinding feed means when the negative pressure value is reached; .

A grinding apparatus according to the present invention includes a holding table having a holding surface for sucking and holding a plate-like workpiece, a grinding means for grinding the plate-like workpiece held by the holding table with a grinding wheel, and the grinding means approaching the holding table. The holding table includes a central suction part, at least one annular outer peripheral suction part surrounding the outer periphery of the central suction part, and a central suction part and an outer peripheral suction part. The grinding device includes a central communication pipe that communicates the central suction part with the suction source, an outer peripheral communication pipe that communicates the outer peripheral suction part with the suction source, and an inner peripheral communication pipe. When the negative pressure value in the outer peripheral pipe measured by the pressure gauge exceeds the negative pressure value set in advance, the outer peripheral part of the plate-like workpiece held by the holding table floats from the holding surface. Due to a the recognizing portion is a raised state,
Even if the outer periphery of the plate-shaped workpiece is warped, the recognition unit recognizes whether the outer periphery of the plate-shaped workpiece is lifted from the holding surface based on the negative pressure value of the outer peripheral communication tube measured by the pressure gauge. It becomes possible. Therefore, it is possible to prevent the plate-like workpiece from being blown off from the holding table and being damaged, and even if the plate-like workpiece is not blown off from the holding table, the outer peripheral portion is thinned due to the lifting of the outer peripheral portion, and the plate-like workpiece is thinned. It is possible to prevent the occurrence of grinding failure that the thickness of the workpiece is not uniform.

  The grinding apparatus according to the present invention provides the grinding feed when the recognition unit recognizes the lifting of the outer peripheral portion of the plate-like workpiece from the holding surface before grinding the plate-like workpiece held by the holding table with the grinding wheel. If the recognition part recognizes the lifting of the outer peripheral part of the plate-like workpiece from the holding surface during grinding of the plate-like workpiece held by the holding table with the grinding wheel, is the grinding feed by the grinding feed means stopped? Or, if the grinding feed means moves the grinding surface of the grinding wheel away from the upper surface of the plate-like workpiece held by the holding table, and the negative pressure value measured by the pressure gauge is less than or equal to the preset negative pressure value, Since the control unit controls the movement of the grinding wheel in the direction approaching the upper surface of the plate-like workpiece held by the holding table by the grinding feed means, the recognition unit is a plate-like workpiece. If it is recognized that the outer peripheral part is lifted, the control unit can control the grinding feed means so that the grinding wheel does not come into contact with the plate-like workpiece, and as described above, the plate-like workpiece can be prevented from being damaged or poorly ground. Can do.

It is a perspective view which shows the structure of an example of a grinding device. It is a disassembled perspective view which shows the structure of a holding table. It is sectional drawing which shows the structure of a holding table. It is sectional drawing which shows the state of the grinding process start of the plate-shaped workpiece | work sucked and hold | maintained with the holding table. It is sectional drawing which shows the state of the grinding process interruption of the plate-shaped workpiece | work sucked and held by the holding table. It is sectional drawing which shows the structure of the modification of a holding table.

  A grinding apparatus 1 shown in FIG. 1 includes an apparatus base 2 extending in the Y-axis direction and a column 3 standing on the rear side of the apparatus base 2 in the Y-axis direction. The grinding apparatus 1 includes a holding table 10 disposed on the upper surface of the apparatus base 2 for sucking and holding a plate-like work, a grinding means 30 for grinding the plate-like work sucked and held by the holding table 10 with a grinding wheel 37, and holding. A grinding feed means 40 for grinding and feeding the grinding means 30 in a grinding feed direction (Z-axis direction) approaching and separating from the table 10, and a thickness measuring means for measuring the thickness of the plate-like workpiece sucked and held by the holding table 10. 50.

  The grinding means 30 is supported by the grinding feed means 40 so as to be movable up and down in front of the column 3. The grinding means 30 includes a spindle 31 having an axis in the Z-axis direction, a spindle housing 32 that surrounds the outer periphery of the spindle 31, a holder 33 that holds the spindle housing 32, and a motor 34 that is attached to one end of the spindle 31. A grinding wheel 36 mounted on the lower end of the spindle 31 via the mount 35 and a plurality of grinding wheels 37 fixed in an annular shape to the lower part of the grinding wheel 36 are provided. When the motor 34 rotates the spindle 31, the grinding wheel 36 can be rotated at a predetermined rotational speed.

  The grinding feed means 40 includes a ball screw 41 extending in the Z-axis direction, a motor 42 connected to one end of the ball screw 41, a pair of guide rails 43 extending in parallel to the ball screw 41, and nuts provided therein. An elevating plate 44 is provided which is screwed into the ball screw 41 and whose side part is in sliding contact with the guide rail 43. A holder 33 is fixed to the lifting plate 44. When the motor 42 rotates the ball screw 41, the grinding means 30 can be moved up and down in the Z-axis direction along with the lift plate 44 along the pair of guide rails 43.

  The thickness measuring means 50 includes a contact type first height gauge 51 and a second height gauge 52. The thickness measuring means 50 measures the upper surface height of the holding table 10 with the first height gauge 51, and measures the upper surface height of the plate-like workpiece held on the holding table 10 with the second height gauge 52, respectively. Can be calculated as the thickness of the plate-like workpiece.

  The holding table 10 includes a porous plate 11 having a holding surface 11a for sucking and holding a plate-like workpiece, a frame body 12 that houses the porous plate 11, and a base 13 on which the frame body 12 is fixed. The periphery of the holding table 10 is covered with a cover 4. Below the holding table 10, although not shown, a rotating means for rotating the holding table 10 and a moving means for moving the holding table 10 together with the cover 4 in the Y-axis direction are connected.

  FIG. 2 shows a configuration in which the holding table 10 is disassembled. The porous plate 11 is formed in a disc shape and is made of a porous member such as porous ceramics. The porous plate 11 includes a central suction part 110, at least one annular outer peripheral suction part 111 surrounding the outer periphery of the central suction part 110, and at least one annular partition that partitions between the central suction part 110 and the outer peripheral suction part 111. The holding surface 11a of the porous plate 11 is divided into two suction areas concentrically around the center of the porous plate 11 by the partitioning portion 112. The central suction part 110 is a suction area for sucking and holding a plate-like workpiece having a small diameter, and is set to have a diameter of 200 mm, for example. On the other hand, the outer periphery suction part 111 is a suction area for sucking and holding a plate-shaped workpiece having a large diameter, and is set to have a diameter of 300 mm, for example. In addition, the number of the partition parts 112 is not restricted to one, You may increase suitably and may make two or more suction areas. Further, the sizes of the central suction part 110 and the outer peripheral suction part 111 can be appropriately set according to the diameter of the plate-like workpiece to be processed.

  A ring-shaped convex portion 121 is formed on the frame body 12, and a region inside the convex portion 121 is a concave portion 120 formed according to the shape of the porous plate 11. The upper surface of the projection 121 is a reference surface 121a having the same height as the holding surface 11a of the porous plate 11, and the height position when the first height gauge 51 shown in FIG. 1 contacts the reference surface 121a. Is measured as the height of the holding surface 11a. The inner diameter of the recess 120 of the frame 12 is formed slightly larger than the outer diameter of the porous plate 11, and the porous plate 11 can be fitted into the recess 120. A plurality of screw through holes 126 for penetrating the screws 5 shown in FIG. 3 are formed in the outer peripheral edge of the frame body 12 so as to penetrate the upper and lower surfaces of the frame body 12.

  The bottom surface 120a of the recess 120 is formed as a flat surface in order to fix the porous plate 11 horizontally. In the bottom surface 120 a of the recess 120, a suction groove 122 communicating with the central suction portion 110 of the porous plate 11, a central suction hole 124 communicating with the suction groove 122 and penetrating the upper and lower surfaces of the frame body 12, and the outer periphery of the porous plate 11 A ring-shaped outer peripheral suction groove 123 communicating with the suction part 111 and an outer peripheral suction hole 125 communicating with the outer peripheral suction groove 123 and penetrating the upper and lower surfaces of the frame body 12 are provided. In the illustrated example, only one central suction hole 124 and one outer peripheral suction hole 125 are formed, but the number and position of the central suction holes 124 and the outer peripheral suction holes 125 are not limited.

  The upper surface 13a of the base 13 is a mounting surface on which the frame body 12 is fixed horizontally. The upper surface 13 a of the base 13 communicates with a central suction hole 130 that penetrates from the upper surface 13 a to the lower surface 13 b of the base 13 and communicates with the central suction hole 124 of the frame 12, and the outer peripheral suction hole 125 of the frame 12. A ring-shaped outer peripheral suction groove 131 that can be formed, an outer peripheral suction hole 132 that communicates with the outer peripheral suction groove 131 and penetrates from the upper surface 13a to the lower surface 13b of the base 13, and a plurality of screw through holes 126 are formed. A plurality of female screw holes 133 are provided.

  When the porous plate 11 is accommodated in the frame body 12, for example, an adhesive is applied to the bottom surface 120a of the recess 120, and then the porous plate 11 is fitted into the recess 120, and the lower surface of the porous plate 11 is bonded and fixed to the bottom surface 120a. Let When the frame body 12 in which the porous plate 11 is accommodated is fixed to the base 13, the screw holes 126 of the frame body 12 are aligned with the positions of the female screw holes 133, and the frame body 12 is fixed to the base 13. Place on the top surface 13a. Thereafter, as shown in FIG. 3, the frame 12 is fixed to the base 13 by screwing the screws 5 that have passed through the screw through holes 126 into the female screw holes 133. The holding table 10 thus configured is used by being mounted on the grinding apparatus 1 shown in FIG. When removing the frame 12 from the base 13, all the screws 5 may be removed from the screw through holes 126 and then the frame 12 may be removed from the base 13.

  As shown in FIG. 3, the grinding apparatus 1 includes a central communication pipe 20 that communicates the central suction part 110 of the porous plate 11 with the suction source 6 on the lower side of the base 13, and an outer peripheral suction part 111 of the porous plate 11. The outer peripheral communication pipe 21 communicated with the suction source 6, the pressure gauge 23a for measuring the negative pressure in the central communication pipe 20, the pressure gauge 23b for measuring the negative pressure in the outer peripheral communication pipe 21, and the pressure gauge 23b were measured. A recognizing unit 24 for recognizing that the outer peripheral portion of the plate-like workpiece held by the holding table 10 is lifted from the holding surface 11a when the negative pressure value in the outer peripheral communication tube 21 becomes larger than a preset negative pressure value. It has.

  The central communication pipe 20 is provided with a valve 22a that allows the suction source 6 and the central suction part 110 of the porous plate 11 to communicate with each other. When the valve 22 a is opened together with the operation of the suction source 6, the suction source 6 and the central suction part 110 communicate with each other, and a negative pressure is generated in the suction groove 122 through the central suction hole 124. It can be demonstrated. In addition, a valve 22 b that connects the suction source 6 and the outer peripheral suction portion 111 of the porous plate 11 is disposed in the outer peripheral communication pipe 21. When the valve 22 b is opened together with the operation of the suction source 6, the suction source 6 and the outer peripheral suction part 111 communicate with each other, and a negative pressure is generated in the outer peripheral suction groove 123 through the outer peripheral suction hole 125. Can be demonstrated.

  The pressure gauge 23a is disposed in the central communication pipe 20 on the base 13 side at a position in the vicinity of the valve 22a. The pressure gauge 23a is provided in the central communication pipe 20 when the plate-like workpiece is sucked and held in the central suction part 110. Negative pressure can be measured. The pressure gauge 23b is disposed in the outer peripheral communication pipe 21 on the base 13 side at a position near the valve 22b, and the outer peripheral communication pipe 21 when the plate-like workpiece is sucked and held in the outer peripheral suction portion 111. The negative pressure inside can be measured. The recognition unit 24 shown in the present embodiment is connected to a pressure gauge 23b located on the outermost side (the outer peripheral side of the holding table 10). When the negative pressure value in the outer communication pipe 21 is constantly monitored by the recognition unit 24, the negative pressure value in the outer communication pipe 21 exceeds the judgment reference value of the negative pressure value preset in the recognition unit 24. Furthermore, it can be recognized that the outer peripheral portion of the plate-like workpiece is in a state of being lifted from the holding surface 11a. Note that the pressure gauges 23a and 23b only need to be able to measure negative pressure, and their configurations are not limited.

  The grinding apparatus 1 shown in FIG. 1 includes a control unit 25 that controls the grinding feed means 40. The control unit 25 includes at least a storage element such as a CPU and a memory, and is connected to the recognition unit 24. For example, before the plate-shaped workpiece held by the holding table 10 is ground by the grinding wheel 37, if the recognition unit 24 sends information indicating that the outer peripheral portion of the plate-shaped workpiece is lifted to the control unit 25, the control unit 25 performs the grinding. Control to stop the grinding feed of the grinding means 30 by the feed means 40 is performed. Further, for example, when the recognition unit 24 sends information that the lifting of the outer peripheral portion of the plate-shaped workpiece is recognized to the control unit 25 during grinding of the plate-shaped workpiece held by the holding table 10 with the grinding wheel 37, the control unit 25. The grinding feed of the grinding means 30 by the grinding feed means 40 is stopped, or the grinding feed means 40 moves the grinding surface of the grinding wheel 37 away from the upper surface of the plate-like workpiece held by the holding table 10, When the negative pressure value measured by the pressure gauge 23b shown in FIG. 2 becomes equal to or lower than the negative pressure value set in advance, the grinding wheel 37 is moved closer to the upper surface of the plate-like workpiece held by the holding table 10 by the grinding feed means 40. Control to move. As described above, even when the holding table 10 sucks and holds a plate-like workpiece having a warped outer peripheral portion, the control unit 25 interrupts the grinding process based on the information recognized by the recognition unit 24. You can also resume grinding.

  Next, an operation example of the grinding apparatus 1 will be described. A plate-like workpiece W shown in FIG. 4 is an example of a circular plate-like workpiece. The upper surface Wa of the plate-like workpiece W is a work surface to be ground by the grinding wheel 37. On the other hand, a device chip or the like is formed on the lower surface Wb opposite to the upper surface Wa, and a protective tape is attached. The plate-like workpiece W shown in the present embodiment is a plate-like workpiece having a large diameter (for example, 12 inches), and the outer peripheral portion Wc of the plate-like workpiece W is the heat generated when the device chip is sealed with the sealing resin. It is assumed that warping has occurred due to the influence. When starting the grinding process, the recognition unit 24 recognizes in advance the judgment reference value of the negative pressure value in the outer peripheral communication pipe 21 when the plate-like workpiece W is properly sucked and held by the outer suction unit 111 of the holding table 10. Set to.

  When the plate-like workpiece W is sucked and held by the holding table 10, as shown in FIG. 4, after the lower surface Wb side of the plate-like workpiece W is placed on the holding surface 11a of the holding table 10, the valve 22a is opened. The suction source 6 and the central suction part 110 are communicated with each other, and the valve 22b is opened to allow the suction source 6 and the outer peripheral suction part 111 to communicate with each other. The plate-like workpiece W is sucked and held. Next, the holding table 10 is rotated by a rotating means (not shown) and moved below the grinding means 30. Note that the holding surface 11a of the holding table 10 is a conical surface inclined downward from the central portion to the outer peripheral side, but is actually a slight inclination that cannot be recognized with the naked eye.

  Here, before the plate-like workpiece W is ground with the grinding wheel 37, the negative pressure value in the outer peripheral communication pipe 21 is measured by the pressure gauge 23 b, and the measurement result is sent to the recognition unit 24. When the negative pressure value measured by the pressure gauge 23b exceeds the determination reference value set in the recognition unit 24 (exceeds the determination reference value in the positive pressure direction), the recognition unit 24 recognizes the plate-like workpiece W. Is recognized as being in a state of being lifted from the holding surface 11 a of the outer peripheral suction part 111, and the information is sent to the control part 25. In this case, the control unit 25 stops the grinding feed of the grinding means 30 by the grinding feed means 40. Thereafter, without starting the grinding process, for example, the warped plate workpiece W may be removed from the holding table 10 and the next plate workpiece W may be conveyed to the holding table 10.

  On the other hand, when the negative pressure value measured by the pressure gauge 23b is equal to or less than the determination reference value set in the recognition unit 24 (exceeds the determination reference value in the negative pressure direction), the recognition unit 24 detects the plate-like workpiece W. It is recognized that the outer peripheral portion Wc is properly sucked and held in the outer peripheral suction portion 111, and the information is sent to the control portion 25. In this case, as shown in FIG. 4, the control unit 25 controls the grinding wheel 37 to move in a direction approaching the upper surface Wa of the plate-like workpiece W held by the holding table 10 by the grinding feed means 40. While the grinding means 30 is lowered by the grinding feed means 40, the grinding means 30 rotates the spindle 31 to rotate the grinding wheel 36 in the direction of the arrow A, for example, and presses the upper surface Wa with the grinding wheel 37 to form a plate shape. The workpiece W is ground to a predetermined thickness. The rotating grinding wheel 37 passes through the center of the upper surface Wa of the plate-like workpiece W and comes into contact with the radius portion in the front view. During the grinding of the plate workpiece, the grinding water is continuously supplied from the grinding water supply source (not shown) toward the grinding wheel 37. For example, pure water is used as the grinding water.

  Whether or not the outer peripheral portion Wc of the plate-shaped workpiece W is properly sucked and held by the outer peripheral suction portion 111 by measuring the negative pressure value in the outer peripheral communication tube 21 with the pressure gauge 23b even during the grinding of the plate-shaped workpiece W. To monitor. When the negative pressure value measured by the pressure gauge 23b exceeds the judgment reference value set in the recognition unit 24, the recognizing unit 24 determines that the outer peripheral portion Wc of the plate-like workpiece W is the outer peripheral as shown in FIG. Recognizing that the surface is lifted from the holding surface 11 a of the suction unit 111, the information is sent to the control unit 25. As shown in the partial enlarged view of FIG. 5, when the outer peripheral portion Wc of the plate-like workpiece W is lifted from the holding surface 11 a of the outer periphery suction portion 111 and a gap is formed between the plate-like workpiece W and the outer periphery suction portion 111, the holding is performed. Since the negative pressure leaks from the surface 11a, even if the plate-like workpiece W blows off from the holding table 10 or the plate-like workpiece W does not blow off from the holding table 10, the plate-like workpiece W after grinding is processed. Variation in thickness occurs. In this case, the control unit 25 controls to stop the grinding feed of the grinding means 30 by the grinding feed means 40 and interrupts the grinding process.

  Further, by temporarily separating the grinding wheel 37 from the plate-like workpiece W, the floating of the outer peripheral portion Wc of the plate-like workpiece W may be eliminated by the hydraulic pressure of the grinding water used during the grinding process. Grinding can be resumed. In this case, the control unit 25 causes the grinding feed means 40 to move the grinding surface of the grinding wheel 37 away from the upper surface Wa of the plate-like workpiece W held by the holding table 10, and the negative pressure value measured by the pressure gauge 23b. Is controlled to move the grinding wheel 37 in a direction approaching the upper surface Wa of the plate-like workpiece W held by the holding table 10 by the grinding feed means 40 at the time when becomes below the predetermined judgment reference value. Resume. Further, the control unit 25 controls the grinding feed means 40 so as to repeat the raising and lowering of the grinding means 30 until the negative pressure value in the outer peripheral communication pipe 21 measured by the pressure gauge 23b becomes equal to or less than the judgment reference value. Also good.

Thus, the grinding apparatus 1 according to the present invention includes the holding table 10 having the holding surface 11a for sucking and holding the plate-like workpiece W. The holding table 10 has a central suction part 110 and an outer periphery of the central suction part 110. A central portion that includes at least one annular outer peripheral suction portion 111 and at least one annular partition portion 112 that partitions between the central suction portion 110 and the outer peripheral suction portion 111, and communicates the central suction portion 110 with the suction source 6. The communication pipe 20, the outer peripheral communication pipe 21 for communicating the outer peripheral suction part 111 with the suction source 6, the pressure gauge 23b for measuring the negative pressure in the outer peripheral communication pipe 21, and the inner diameter of the outer peripheral communication pipe 21 measured by the pressure gauge 23b Recognition that the outer peripheral portion Wc of the plate-like workpiece W held by the holding table 10 is lifted from the holding surface 11a when the negative pressure value becomes larger than the preset negative pressure value. 24, the recognizing unit 24 can detect the outer peripheral portion of the plate-like workpiece W based on the negative pressure value of the outer peripheral communication tube 21 measured by the pressure gauge 23b even if the outer peripheral portion Wc of the plate-like workpiece W is warped. It becomes possible to recognize whether Wc is lifted from the holding surface 11a. Accordingly, it is possible to prevent the plate-like workpiece W from being blown off from the holding table 10 and being damaged, and even if the plate-like workpiece W is not blown off from the holding table 10, the outer peripheral portion Wc is caused by the rising of the outer peripheral portion Wc. Therefore, it is possible to prevent the occurrence of poor grinding that the thickness of the plate-like workpiece W is not uniform.
Further, the grinding device 1 stops the grinding feed means 40 when the recognition unit 24 recognizes the lifting of the outer peripheral portion Wc of the plate-like workpiece W from the holding surface 11a before the grinding process, and the recognition unit 24 performs the holding surface during the grinding process. When the lifting of the outer peripheral portion Wc of the plate-like workpiece W is recognized from 11a, the grinding feed means 40 is stopped, or the grinding surface of the grinding wheel 37 is moved away from the upper surface Wa of the plate-like workpiece W, and the pressure gauge 23b When the negative pressure value to be measured becomes equal to or less than the negative pressure value set in advance, the control unit 25 is provided for controlling the grinding wheel 37 to move in the direction approaching the upper surface Wa of the plate-like workpiece W by the grinding feed means 40. When the recognition unit 24 recognizes the lifting of the outer peripheral portion Wc of the plate-like workpiece W, the control unit 25 performs grinding and feeding so that the grinding wheel 37 does not contact the plate-like workpiece W. Can control the unit 40, the same, it is possible to prevent breakage of or grinding failure of the plate-shaped workpiece W.

  A holding table 10 </ b> A illustrated in FIG. 6 is a modification of the holding table 10. The porous plate 11A of the holding table 10A includes an annular first outer periphery suction part 114 surrounding the outer periphery of the central suction part 110, an annular second outer periphery suction part 115 surrounding the outer periphery of the first outer periphery suction part 114, An annular partition 112 that partitions the central suction portion 110 and the first outer periphery suction portion 114; an annular partition 113 that partitions the first outer periphery suction portion 114 and the second outer periphery suction portion 115; The holding surface 11a of the porous plate 11A is configured to be divided into three suction areas concentrically around the center of the porous plate 11A by the partition portions 112 and 113. In the holding table 10A, the same components as those of the holding table 10 are denoted by common reference numerals.

  The frame body 12A includes a ring-shaped first outer periphery suction groove 123a that communicates with the first outer periphery suction portion 114, and a first body that communicates with the first outer periphery suction groove 123a and penetrates the upper and lower surfaces of the frame body 12A. The outer peripheral suction hole 125a, the ring-shaped second outer peripheral suction groove 123b communicating with the second outer peripheral suction portion 115, and the second outer peripheral suction groove 123b communicating with the second outer peripheral suction groove 123b and penetrating the upper and lower surfaces of the frame body 12A. And an outer peripheral suction hole 125b. The base 13A includes a ring-shaped first outer peripheral suction groove 131a that communicates with the first outer peripheral suction hole 125a, and a first through the upper and lower surfaces of the base 13A that communicates with the first outer peripheral suction groove 131a. The outer peripheral suction hole 132a, the ring-shaped second outer peripheral suction groove 131b communicating with the second outer peripheral suction hole 125b, and the second outer peripheral suction groove 131b communicating with the second outer peripheral suction groove 131b and penetrating the upper and lower surfaces of the base 13A. And an outer peripheral suction hole 132b.

  On the lower side of the base 13A, a first outer peripheral communication pipe 26 that communicates the first outer peripheral suction portion 114 of the porous plate 11A with the suction source 6 and a second outer peripheral suction portion 115 of the porous plate 11A are provided as the suction source. 6, a second outer peripheral communication pipe 27 that communicates with the first outer peripheral communication pipe 26, a pressure gauge 23 b that measures the negative pressure in the first outer peripheral communication pipe 26, and a pressure gauge 23 c that measures the negative pressure in the second outer peripheral communication pipe 27. When the negative pressure value in the second outer peripheral communication pipe 27 measured by the pressure gauge 23c becomes larger than the preset negative pressure value, the outer peripheral portion of the plate-like workpiece held by the holding table 10A is lifted from the holding surface 11a. A recognizing unit 24A for recognizing this.

  The first outer peripheral communication pipe 26 is provided with a valve 22b that allows the suction source 6 and the first outer peripheral suction portion 114 to communicate with each other. When the valve 22b is opened along with the operation of the suction source 6, the suction source 6 and the first outer peripheral suction portion 114 communicate with each other, and a negative pressure is generated in the first outer peripheral suction groove 123a through the first outer peripheral suction hole 125a. Thus, the first outer peripheral suction portion 114 can exert a suction action. In addition, the second outer peripheral communication tube 27 is provided with a valve 22c that allows the suction source 6 and the second outer peripheral suction portion 115 to communicate with each other. When the valve 22c is opened along with the operation of the suction source 6, the suction source 6 and the second outer peripheral suction portion 115 communicate with each other, and a negative pressure is generated in the second outer peripheral suction groove 123b through the second outer peripheral suction hole 125b. Thus, the second outer peripheral suction portion 115 can exert a suction action.

  The pressure gauge 23b is attached to the first outer peripheral communication pipe 26 on the base 13A side at a position near the valve 22b, and the first outer peripheral suction part 114 sucks and holds the plate-like workpiece. The negative pressure in one outer peripheral communication pipe 26 can be measured. The pressure gauge 23c is attached to the second outer peripheral communication pipe 27 on the base 13A side at a position in the vicinity of the valve 22c, and the second outer peripheral suction part 115 sucks and holds the plate-like workpiece. The negative pressure in the second outer peripheral communication pipe 27 can be measured. The recognition unit 24A is connected to a pressure gauge 23c located on the outermost side (the outer peripheral side of the holding table 10A). By constantly monitoring the negative pressure value in the second outer peripheral communication pipe 27 by the recognition unit 24A, the negative pressure value in the second outer peripheral communication pipe 27 is determined in advance in the recognition unit 24A. Can be recognized as the state where the outer peripheral portion of the plate-like workpiece is lifted from the holding surface 11a. Even if the holding table 10A configured as described above sucks and holds a plate-like workpiece having a warped outer peripheral portion, it is possible to prevent the plate-like workpiece from being broken or from being poorly ground.

1: Grinding device 2: Device base 3: Column 4: Cover 5: Screw 6: Suction source 10, 10A: Holding table 11, 11A: Porous plate 110: Central suction part 111: Outer peripheral suction part 112, 113: Partition part 114 : 1st outer periphery suction part 115: 2nd outer periphery suction part 12, 12A: Frame 120: Concave part 121: Convex part 122: Suction groove 123: Outer periphery suction groove 124: Center suction hole 125: Outer periphery suction hole 126: Screw Through holes 13, 13A: base 130: central suction hole 131: outer peripheral suction groove 132: outer peripheral suction hole 133: female screw hole 20: central communication pipe 21: outer peripheral communication pipe 22a, 22b, 22c: valves 23a, 23b, 23c : Pressure gauge 24, 24A: Recognition unit 25: Control unit 26: First outer peripheral communication tube 27: Second outer peripheral communication tube 30: Grinding means 31: Spindle 32: Spindle Housing 33: Holder 34: Motor 35: Mount 36: Grinding wheel 37: Grinding wheel 40: Grinding feed means 41: Ball screw 42: Motor 43: Guide rail 44: Elevating plate 50: Thickness measuring means 51: First height gauge 52: Second height gauge

Claims (2)

A holding table having a holding surface for sucking and holding the plate-like workpiece, a grinding means for grinding the plate-like workpiece held by the holding table with a grinding wheel, and a direction in which the grinding means approaches and separates from the holding table A grinding device comprising a grinding feed means for feeding by grinding,
The holding table includes a central suction part,
At least one annular outer peripheral suction portion surrounding the outer periphery of the central suction portion;
At least one annular partition that partitions between the central suction portion and the outer periphery suction portion;
In the grinding apparatus, a central communication pipe for communicating the central suction part with a suction source;
An outer peripheral communication pipe for communicating the outer peripheral suction part with the suction source;
A pressure gauge for measuring a negative pressure in the outer communication pipe;
When the negative pressure value measured by the pressure gauge in the outer communication pipe becomes larger than a preset negative pressure value, it is recognized that the outer peripheral portion of the plate-like workpiece held by the holding table is lifted from the holding surface. A grinding apparatus comprising: a recognition unit; Before the plate-like workpiece held by the holding table is ground by the grinding wheel, when the recognition unit recognizes the lifting of the outer peripheral portion of the plate-like workpiece from the holding surface, the grinding feed means is stopped,
During the grinding process of the plate-like workpiece held by the holding table with the grinding wheel, if the recognition unit recognizes the lifting of the outer peripheral portion of the plate-like workpiece from the holding surface, the grinding feed by the grinding feed means is stopped. Or the grinding feed means moves the grinding surface of the grinding wheel away from the upper surface of the plate-like workpiece held by the holding table, and the negative pressure value measured by the pressure gauge is a preset negative pressure value. The grinding apparatus according to claim 1, further comprising a control unit that performs control to move the grinding wheel in a direction approaching the upper surface of the plate-like workpiece held by the holding table by the grinding feed unit.

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