JP2018012179A - Grinding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding apparatus that can grind a plate-like workpiece to be ground until a thickness thereof reaches a predetermined value, even when the type of the plate-like workpiece to be ground is changed.SOLUTION: A grinding apparatus 1 comprises: grinding means 10 for rotating a grinding wheel 15 by grindstone rotation means, and grinding a plate-like workpiece W; and determination means 30 for determining whether or not electrodes We are exposed from a surface Wa to be ground. The determination means 30 includes: a storage section for storing a load current value detected by load current value detection means 112 when the electrodes We are not ground by a grindstone 16; a setting section for multiplying the load current value by a preset coefficient, and setting the obtained value as a reference load current value when the electrodes We are exposed from the surface Wa to be ground; and a determination section for determining that the electrodes We are exposed from the surface Wa to be ground when the load current value during the grinding reaches the reference load current value. This configuration can set the reference load current value depending on types of the plate-like workpiece W and the grinding wheel 15, and allows the plate-like workpiece W to be ground until the electrodes We are reliably exposed from the surface Wa to be ground.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a grinding apparatus for grinding a workpiece such as a plate workpiece.

  A processing apparatus for grinding a plate workpiece includes a holding table for holding a plate workpiece, a grinding means having a grinding wheel to which a grinding wheel is fixed in an annular shape, a motor for rotating the grinding wheel, and a grinding means as a holding table. It includes at least processing feed means for feeding the workpiece in a direction approaching and moving away from the held plate-like workpiece, and is ground while pressing the plate-like workpiece with a grinding wheel.

  In processing equipment, when grinding a plate-shaped workpiece with an electrode inside and exposing the electrode to the surface to be ground, the load current value of the motor that rotates the grinding wheel when the grinding wheel reaches the electrode during grinding Changes. Therefore, the machining means is provided with a load current value detecting means, and the load current value detecting means constantly monitors the change of the load current value generated when grinding the plate workpiece and controls the machining feed means to control the plate workpiece. There is a grinding device that grinds to a desired thickness (see, for example, Patent Documents 1 and 2 below).

JP 2014-008538 A JP 2013-056392 A

  However, in the grinding apparatus as described above, grinding is controlled when the load current value exceeds a preset reference value, so grinding starts depending on the type of plate workpiece to be ground. Immediately after the load current value reaches the reference value. In other words, if you try to grind different types of plate workpieces while setting the reference value when grinding the plate workpieces before the type is changed in the grinding device, it is in a state where the predetermined thickness has not been reached. However, there is a problem that the grinding of the plate-like workpiece is finished.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to enable grinding to a predetermined thickness even when the type of plate workpiece to be ground is changed.

  The present invention provides a holding table having a holding surface for holding a plate-like workpiece having a plurality of electrodes therein, a holding table rotating means for rotating the holding table around the center of the holding table, and a grinding wheel in an annular shape Grinding means for grinding a plate-like workpiece held by a holding table by rotating a grinding wheel by means of a grindstone rotating means, which is equipped with a grindstone rotating means for mounting the disposed grinding wheel on a rotating shaft and rotating the grinding wheel about the rotating shaft; A grinding feed means for grinding and feeding the grinding means in a direction approaching and separating from the holding table; a judging means for judging that the electrode is exposed on a surface to be ground of a plate-like workpiece to be ground by the grinding means; The grindstone rotating means includes a motor that rotates the rotating shaft, and a load current value detecting means that detects a load current value of the motor. A storage unit for storing the load current value detected by the load current value detecting means when the electrode is not being ground while grinding the plate-like workpiece with the grinding wheel, and a coefficient preset for the load current value stored by the storage unit The setting part that sets the value multiplied by as the reference load current value when the electrode is exposed on the surface to be ground, and when the load current value during grinding reaches the reference load current value set in the setting part A determination unit that determines that the electrode is exposed on the surface.

  The present invention further includes a thickness measuring means for measuring the thickness of the plate workpiece to be ground by the grinding means, and the thickness measuring means is flush with the holding surface outside the plate workpiece held on the holding table. A first measuring device that contacts the first measuring element to measure the height of the holding surface, and a second measuring element that contacts the upper surface of the plate-like workpiece held by the holding surface to increase the height of the upper surface of the plate-like workpiece. A second measuring device that measures the thickness, and a calculation unit that calculates the difference between the value of the first measuring device and the value of the second measuring device as the thickness of the plate-like workpiece, and is equal to or higher than the height of the electrode The value is set in advance as the set thickness, and the plate-like workpiece is ground by the grinding means while measuring the thickness of the plate-like workpiece by the thickness measuring means until the set thickness is reached, and the load current value detecting means detects during the grinding. The load current value can be stored in the storage unit.

  The grinding apparatus includes correlation data in which a coefficient is set according to the correlation between the type of the grinding wheel and the density of a plurality of electrodes provided on the plate-like workpiece, and the type of the grinding wheel mounted on the rotating shaft, and the plate A selection means for selecting the coefficient with reference to the correlation data based on the density of the electrode of the workpiece may be provided.

  In the grinding device according to the present invention, the grinding wheel is rotated by the grindstone rotating means to grind the plate workpiece held by the holding table, and the electrode is exposed on the surface to be ground of the plate workpiece to be ground by the grinding means. The grindstone rotating means includes a motor for rotating the rotating shaft, and a load current value detecting means for detecting the load current value of the motor. A storage unit for storing the load current value detected by the load current value detecting means when the electrode is not being ground during grinding, and the load current value stored by the storage unit is multiplied by a preset coefficient to cover the electrode. Setting part to be set as the reference load current value when exposed to the grinding surface, and judgment that the electrode is exposed on the surface to be ground when the load current value during grinding reaches the reference load current value set in the setting part Judgment Therefore, the load current value when the electrode is not exposed from the surface to be ground during grinding of the plate workpiece is recorded even when the plate workpiece to be ground or the type of grinding wheel is changed. It is possible to set a reference load current value as a judgment criterion when the electrode is exposed on the surface to be ground, simply by storing in 100 million parts and multiplying the load current value by a preset coefficient. Therefore, the plate-like workpiece can be ground until the electrode is reliably exposed on the surface to be ground.

  Further, the grinding apparatus according to the present invention includes a thickness measuring means for measuring the thickness of the plate-shaped workpiece to be ground by the grinding means, and sets a value equal to or higher than the height of the electrode in advance as the set thickness. Since the plate workpiece is ground by the grinding means while measuring the thickness of the plate workpiece until the thickness is reached, the load current value is detected during grinding while monitoring the thickness change of the plate workpiece. The load current value detected by the means can be stored in the storage unit. Therefore, it is possible to grind the plate-shaped workpiece until the electrode is exposed to the ground surface more reliably while constantly monitoring the thickness of the plate-shaped workpiece and the load current value.

  The grinding apparatus includes correlation data in which a coefficient is set according to the correlation between the type of the grinding wheel and the density of a plurality of electrodes provided on the plate-like workpiece, and the type of the grinding wheel mounted on the rotary shaft, and the plate When selecting means to select the coefficient by referring to the correlation data according to the density of the electrode of the workpiece, refer to the correlation data according to the type of plate workpiece to be ground and the type of grinding wheel Since an optimum coefficient can be selected, it is possible to set an accurate reference load current value according to the type of plate workpiece and the type of grinding wheel.

It is a perspective view which shows the structure of an example of a grinding device. (A) is a first example of correlation data. (B) is a second example of correlation data. It is sectional drawing which shows the state which grinds and feeds a grinding means toward the plate-shaped workpiece | work hold | maintained at the holding table. It is sectional drawing which shows the state which grinds a plate-shaped workpiece | work with a grinding means, and the state where the electrode is not exposed to the to-be-ground surface of a plate-shaped workpiece. It is sectional drawing which shows the state by which the plate-shaped workpiece was ground by predetermined thickness and the electrode was exposed to the to-be-ground surface of the plate-shaped workpiece. It is sectional drawing which shows the state which carries out grinding feed toward the plate-shaped workpiece | work hold | maintained at the holding | maintenance table of the modification of a grinding means. Sectional drawing which shows the state which forms the recessed part in the center of a plate-shaped workpiece | work by the modification of a grinding means, and forms a convex part on the outer peripheral side, and the state which the electrode is not exposed to the to-be-ground surface of a plate-shaped workpiece It is. It is sectional drawing which shows the state in which the predetermined recessed part was formed in the center of a plate-shaped workpiece | work, and the electrode was exposed to the to-be-ground surface of a plate-shaped workpiece.

  A grinding apparatus 1 shown in FIG. 1 is an example of a grinding apparatus that can grind a plate-shaped workpiece having a plurality of electrodes therein. The grinding device 1 includes a device base 100 extending in the Y-axis direction and a column 101 erected on the rear side of the device base 100 in the Y-axis direction. The apparatus base 100 includes a holding table 2 having a holding surface 2a for holding a plate-like workpiece having a plurality of electrodes therein, and a holding table rotating means 4 that rotates around the center of the holding table 2. . The periphery of the holding surface 2a of the holding table 2 is surrounded by the frame 3, and the upper surface of the frame 3 is a reference surface 3a having the same height as the holding surface 2a. The periphery of the holding table 2 is covered with a cover 5 and can be moved in the Y-axis direction by a moving means (not shown). The holding table rotating means 4 is a motor and can rotate the holding table 2 at a predetermined rotation speed.

  The grinding apparatus 1 includes a grinding means 10 for grinding a plate-like work held by a holding table 2, a grinding feed means 20 for grinding and feeding the grinding means 10 in a direction to approach and separate the holding table 2, and a grinding means. 10 is provided with a judging means 30 for judging that the electrode is exposed on the surface to be ground of the plate-like workpiece to be ground by 10, and a control means 40 for controlling the grinding feed means 20. The control means 40 includes at least a storage element such as a CPU and a memory, and is connected to the determination means 30.

  The grinding means 10 is supported by the grinding feed means 20 so as to be movable up and down in front of the column 101. The grinding means 10 includes a grinding wheel 15 in which a grinding wheel 16 is annularly arranged, and a grinding wheel rotating means 11 that rotates the grinding wheel 15. The grindstone rotating means 11 includes a rotating shaft 110 having an axis in the Z-axis direction, a motor 111 that rotates the rotating shaft 110, and a load current value detecting means 112 that detects a load current value of the motor 111. The rotating shaft 110 is rotatably supported by the housing 13, and the housing 13 is held by the holder 12. The grinding wheel 15 is mounted via the mount 14 at the lower end of the rotating shaft 110. In the grindstone rotating means 11, the motor 111 rotates the rotating shaft 110, and the grinding wheel 15 can be rotated about the rotating rotating shaft 110. The load current value detecting means 112 is connected to the motor 111, and can always detect the grinding load applied to the motor 111 as the load current value during grinding of the plate workpiece.

  The grinding feed means 20 includes a ball screw 21 extending in the Z-axis direction, a motor 22 connected to one end of the ball screw 21, a pair of guide rails 23 extending in parallel with the ball screw 21, and a grinding means on one surface. And a lifting plate 24 to which 10 is connected. The pair of guide rails 23 are in sliding contact with the other surface of the lift plate 24, and a ball screw 21 is screwed into a nut formed on the other surface side of the lift plate 24. When the ball screw 21 is rotated by the motor 22, the grinding feed unit 20 can move the lifting unit 24 in the Z-axis direction along the pair of guide rails 23, thereby moving the grinding unit 10 in the Z-axis direction. .

  The determination unit 30 includes a storage unit 31 that stores the load current value detected by the load current value detection unit 112, and a value obtained by multiplying the load current value stored by the storage unit 31 by a preset coefficient. The setting unit 32 that is set as a reference load current value when exposed to the surface to be ground, and the plate workpiece to be ground when the load current value during grinding reaches the reference load current value set in the setting unit 32 And a determination unit 33 for determining that the electrode is exposed on the surface. The storage unit 31 includes a grinding load of the motor 111 when the grinding wheel 16 is not grinding an electrode inside the plate-like workpiece among grinding loads applied to the motor 111 when the plate-like workpiece is ground by the grinding wheel 16. The load current value indicating the load is recorded. The coefficient used for setting the reference load current value in the setting unit 32 is determined in advance as a constant, for example, by performing grinding experimentally using a plurality of types of plate workpieces or a plurality of types of grinding wheels. The setting unit 32 individually sets the grinding wheel 16 provided in the grinding wheel 15 according to the particle size of the grinding wheel 16 and the density of the electrodes provided in the plate-like workpiece. In the setting unit 32, a value obtained by multiplying the load current value by the above coefficient is set as a reference load current value serving as a criterion for determining whether or not the electrode is exposed from the surface to be ground of the plate workpiece. And when the load current value during grinding of the plate workpiece reaches the reference load current value, the determination unit 33 can determine that the electrode is exposed on the surface to be ground of the plate workpiece, The determination result is sent to the control means 40.

  In the vicinity of the holding table 2, a thickness measuring means 60 for measuring the thickness of the plate workpiece to be ground by the grinding means 10 is provided. The thickness measuring means 60 is configured such that the first measuring element 61a is brought into contact with the reference surface 3a that is the same surface as the holding surface 2a outside the plate-like workpiece held by the holding table 2, and the height of the holding surface 2a of the holding table 2 is increased. A first measuring device 61 for measuring the height, and a second measuring device for measuring the upper surface height of the plate-shaped workpiece by bringing the second measuring element 62a into contact with the upper surface of the plate-shaped workpiece held on the holding surface 2a. 62, and a calculation unit 63 that calculates the difference between the measured value measured by the first measuring instrument 61 and the measured value measured by the second measuring instrument 62 as the thickness of the plate-like workpiece.

  The grinding apparatus 1 includes a storage means for storing correlation data D in which a coefficient is set according to the type of grinding wheel and the electrode density of the plate workpiece, and is actually used from the correlation data D. The optimum coefficient to be multiplied by the load current value stored in the storage section 31 is selected with reference to data corresponding to the type of grinding wheel to be processed and the electrode density of the plate-like workpiece to be actually ground. A selection means 50 is provided. The selection unit 50 is connected to the determination unit 30. The electrode density is a ratio between the total area of the plate-like workpiece and the area of a plurality of electrodes arranged inside the plate-like workpiece.

  The correlation data D1 shown in FIG. 2A is a first example of the correlation data D. The plate-like workpiece used for acquiring the correlation data D1 is a plate-like workpiece made of, for example, silicon, and a load current indicating a grinding load of the motor when a portion where no electrode is present is ground with a grinding wheel. It is assumed that the value is 6A (ampere). The grinding wheel used in the experiment has four types of abrasive grain sizes of # 2000, # 3000, # 4000, and # 8000, and the electrode density of the plate-like workpiece is 10%, 30%, and 50%. It is set. For example, when a plate-like workpiece having an electrode density of 10% is ground with a grinding wheel having a grain size of # 2000, the coefficient is set to 1.1. Therefore, by multiplying the load current value 6A by the coefficient 1.1, it is derived that the load current value indicating that the electrode is exposed on the surface to be ground of the plate-like workpiece is 7A. The reference load current value of the correlation data D1 is expressed by rounding off the numerical value actually calculated.

  The correlation data D2 shown in FIG. 2B is a second example of the correlation data D. The plate-like workpiece used to obtain the correlation data D2 is a plate-like workpiece made of resin, and the load current value indicating the grinding load of the motor when grinding a portion where no electrode exists is 10A. It shall be. The electrode density of the grinding wheel and the plate-like workpiece used in the experiment is set similarly to the correlation data D1. For example, when a plate-like workpiece having an electrode density of 30% is ground with a grinding wheel having an abrasive grain size of # 2000, the coefficient is set to 1.3. Therefore, by multiplying the load current value 10A by the coefficient 1.3, the load current value indicating that the electrode is exposed on the surface to be ground of the plate-like workpiece is derived to be 13A. The reference load current value of the correlation data D2 is also shown by rounding off the numerical value actually calculated.

  Here, the larger the value of the grain size of the abrasive grains, the larger the contact area where the grinding wheel contacts the surface to be ground of the plate-like workpiece. That is, as the contact area between the grinding wheel and the electrode increases, the grinding load applied to the motor also increases, so the load current value also increases. Referring to the correlation data D1 and D2, as the value of the abrasive grain size increases as # 2000 ... # 4000 ..., the coefficient to be multiplied by the load current value before the electrode is exposed on the surface to be ground of the plate-like workpiece is also calculated. The reference load current value is also increased by calculation using such a coefficient. Moreover, since the contact area between the grinding wheel and the electrode increases as the electrode density increases from 10% to 30% to 50%, the coefficient is set to be large. However, since the grinding load applied to the motor 111 increases as the combination of a grinding wheel having a larger grain size value and a plate-like workpiece having a higher electrode density increases, the load current value also increases. Therefore, in the correlation data D1 and D2, the coefficient when the grain size value of the abrasive grains is # 8000 and the electrode density is 50% is set to 2.5, which is the highest. In the selection means 50 shown in FIG. 1, the optimum coefficient is selected with reference to the correlation data D1 and D2 according to the type of the plate workpiece to be ground and the type of the grinding wheel 15, and the setting unit At 32, a reference load current value can be set which serves as a determination reference indicating that the electrode is exposed on the surface to be ground of the plate-like workpiece.

  Next, the operation | movement which grinds the plate-shaped workpiece | work W shown in FIG. 3 using the grinding apparatus 1 is demonstrated. The plate-like workpiece W is an example of a workpiece, and includes, for example, a silicon substrate or a resin substrate, and a plurality of electrodes We are formed therein. The electrode We is made of a conductive member, and for example, a metal such as copper (Cu) or a copper alloy can be used. Further, the exposed upper surface of the plate-like workpiece W held on the holding table 2 is a surface to be ground Wa to be ground by the grinding means 10. In the grinding apparatus 1, a value equal to or greater than the height of the electrode We (the length in the thickness direction of the plate-like workpiece W) is set in the control means 40 in advance as the set thickness of the plate-like workpiece W. The set thickness of the plate-like workpiece W is the thickness of the plate-like workpiece W immediately before the grinding wheel 16 fed by grinding reaches the electrode We.

  First, as shown in FIG. 3, the plate-like workpiece W is placed on the holding table 2 to expose the surface Wa to be ground upward. After holding the plate-like workpiece W with the holding table 2, the holding table 2 is moved below the grinding means 10. Subsequently, the holding table 2 is rotated in the direction of arrow A, for example, and the rotating shaft 110 is rotated by the motor 111 to rotate the grinding wheel 15 in the direction of arrow A, for example, and the grinding wheel 15 is held by the grinding feed means 20. Lower in the direction approaching. Then, the grinding wheel 16 that descends while rotating is brought into contact with the surface Wa of the plate-like workpiece W for grinding.

  As shown in FIG. 4, as the plate-shaped workpiece W is ground, the surface to be ground Wa approaches the upper end of the electrode We when the plate-shaped workpiece W is thinned. At this time, since the grinding wheel 16 is not in contact with the electrode We inside the plate-like workpiece W, the load current value detecting means 112 detects the load current value indicating the grinding load of the motor 111, and the judging means 30 It is stored in the storage unit 31 shown in FIG. Then, the setting unit 32 multiplies the load current value stored in the storage unit 31 by a coefficient set in advance in the determination unit 30 so that the electrode We is exposed to the ground surface Wa of the plate-like workpiece W. A reference load current value indicating is set.

  For example, when the plate-like workpiece W to be ground is a silicon substrate (electrode density is 10%) and the grain size of the abrasive grains is # 4000, the selection means 50 shown in FIG. The optimum coefficient 1.3 is selected with reference to the correlation data D1 shown in FIG. Thereafter, the setting unit 32 multiplies the load current value 6A stored in the storage unit 31 by the coefficient 1.3 selected by the selection unit 50 to the surface to be ground Wa of the plate-like workpiece W. It is set as a reference load current value indicating when the electrode We is exposed. Further, for example, when the plate-like workpiece W to be ground is a resin substrate (electrode density is 30%) and the grain size of the abrasive grains is # 8000, the selection means 50 shown in FIG. The optimum coefficient 1.8 is selected with reference to the correlation data D2. Thereafter, the setting unit 32 multiplies the load current value 10A stored in the storage unit 31 by the factor 1.8 selected by the selection means 50 and applies 18A to the surface Wa to be ground of the plate-like workpiece W. It is set as a reference load current value indicating when the electrode We is exposed. As described above, since the selection unit 50 can select the optimum coefficient with reference to the correlation data D1 and D2, an accurate reference load current according to the type of the plate-like workpiece W and the type of the grinding wheel. A value can be set.

  After setting the reference load current value in this manner, the plate-like workpiece W is continuously ground while the thickness of the plate-like workpiece W is measured by the thickness measuring means 60 until the set thickness is reached. During grinding, the load current value detecting means 112 always monitors the change in grinding load applied to the motor 111. If the load current value of the motor 111 detected by the load current value detecting means 112 does not reach the reference load current value, the determination unit 33 does not expose the electrode We to the ground surface Wa of the plate-like workpiece W. The determination result is sent to the control means 40. The control means 40 controls the grinding feed means 20 to continue grinding the plate workpiece W until the load current value of the motor 111 reaches the reference load current value. On the other hand, when the load current value of the motor 111 detected by the load current value detecting means 112 reaches the reference load current value, the determination unit 33 causes the electrode We to be applied to the ground surface Wa of the plate workpiece W as shown in FIG. Is determined to be exposed, and the determination result is sent to the control means 40. Then, the control means 40 controls the grinding feed means 20 to raise the grinding means 10 and finish the grinding of the plate workpiece W.

Thus, the grinding apparatus 1 according to the present invention includes a grinding means 10 for grinding the plate-like workpiece W held by the holding table 2 by rotating the grinding wheel 15 by the grindstone rotating means 11, and a plate to be ground by the grinding means 10. And a judging means 30 for judging that the electrode We is exposed on the surface Wa to be ground of the workpiece W. The grindstone rotating means 11 detects a motor 111 for rotating the rotating shaft 110 and a load current value of the motor 111. Load current value detection means 112, and the determination means 30 stores the load current value detected by the load current value detection means 112 when the electrode We is not being ground while the plate-like workpiece W is being ground with the grinding wheel 16. And a setting that is set as a reference load current value when the electrode We is exposed to the ground surface Wa by multiplying the load current value stored in the storage unit 31 by a coefficient set in advance. Since it includes the unit 32 and the determination unit 33 that determines that the electrode We is exposed on the surface to be ground Wa when the load current value during grinding reaches the reference load current value set in the setting unit 32, the grinding is performed. Even if the type of the plate-like workpiece W to be changed or the type of the grinding wheel 15 is changed, the electrode We is provided on the surface to be ground Wa according to the changed plate-like workpiece W or the changed grinding wheel 15. It is possible to set a reference load current value which is a determination criterion when exposed. Therefore, it becomes possible to grind the plate-like workpiece W until the electrode We is reliably exposed to the surface to be ground Wa.
Moreover, in the grinding apparatus 1, in addition to monitoring the change of the load current value by the load current value detecting means 112 and the judging means 30, the thickness measuring means 60 can always monitor the change of the thickness of the plate workpiece W. It becomes possible to grind the plate-like workpiece W until the electrode We is exposed to the ground surface Wa more reliably.

  The present invention is not limited to the configuration of the grinding apparatus 1 described above, and can be applied to, for example, the grinding apparatus 1A shown in FIG. As a modification of the grinding means, the grinding apparatus 1A includes a grinding means 70 that forms a concave portion in the center of the plate-like workpiece W1 held by the holding table 2A and forms a convex portion on the outer periphery Wc side. The grinding device 1 </ b> A has the same configuration as the grinding device 1 except that the grinding device 70 is provided.

  The grinding means 70 includes a grinding wheel 75 in which a grinding wheel 76 is annularly arranged, and a grinding wheel rotating means for rotating the grinding wheel 75. The grindstone rotating means includes a rotating shaft 71, a motor 72 that rotates the rotating shaft 71, and load current value detecting means 73 that detects a load current value of the motor 72. The grinding wheel 75 is attached to the lower end of the rotating shaft 71 via a mount 74, and the motor 72 rotates around the rotating shaft 71 at a predetermined rotational speed, thereby rotating the grinding wheel 75 at a predetermined rotational speed. Can be made. The load current value detection means 73 can detect a change in the grinding load of the motor 72 during the grinding of the plate workpiece as a load current value. As the grinding wheel 75, the diameter of the outermost circumference of the rotation trajectory of the grinding wheel 76 is not less than the radius of the recess 80 shown in FIG. 7 formed in the plate-like workpiece W1 and not more than the diameter of the recess 80. The grinding wheel 76 may be configured to always pass through the center of the plate-like workpiece W. Note that the size of the grinding wheel 75 can be appropriately changed according to the size of the plate-like workpiece W1 to be ground.

  Next, the operation | movement which grinds the plate-shaped workpiece W1 using 1 A of grinding apparatuses is demonstrated. Similar to the above-described grinding apparatus 1, a value equal to or higher than the height of the electrode We is set in the control means 40A in advance as the set thickness of the plate-like workpiece W1.

  First, as shown in FIG. 6, the plate-like workpiece W1 is placed on the holding table 2A, and the surface to be ground Wa is exposed upward. After holding the plate-like workpiece W <b> 1 with the holding table 2 </ b> A, the holding table 2 </ b> A is moved below the grinding means 70. Subsequently, while the holding table 2A is rotated in the direction of arrow A, for example, the rotating shaft 71 is rotated by the motor 72 and the grinding wheel 75 is rotated in the direction of arrow A, for example, while the grinding wheel 75 is held by the grinding feed means 20A. Lower in the direction approaching. As shown in FIG. 7, grinding is performed by bringing a grinding wheel 76 that descends while rotating into contact with the surface Wa to be ground in the central portion of the plate-like workpiece W1. That is, by grinding for a predetermined time so that the outermost periphery of the grinding wheel 76 always passes through the center of the plate-like workpiece W1, a concave portion 80 is formed in the central portion of the plate-like workpiece W1, and a ring-like shape is formed on the outer circumference Wc side. Protrusions 81 are formed.

  As grinding of the plate-like workpiece W1 progresses, when the concave portion 80 of the plate-like workpiece W1 is thinned, the surface Wa to be ground approaches the upper end of the electrode We. At this time, since the grinding wheel 76 is not in contact with the electrode We inside the plate-like workpiece W1, the load current value detecting means 73 detects the load current value indicating the grinding load of the motor 72, and the determination means 30A Let the billions of copies you have to record. Then, when the electrode We is exposed to the surface to be ground Wa of the plate-like workpiece W1 by multiplying the load current value stored in the storage unit by the setting unit included in the determination unit 30A by a coefficient set in advance. Set the reference load current value shown. Although not shown in the figure, the grinding device 1A also refers to the correlation data according to the type of the plate-like workpiece W1 to be ground and the type of the grinding wheel 75, as in the grinding device 1, An optimum coefficient may be selected, and a reference load current value serving as a determination reference indicating a state in which the electrode We is exposed on the surface to be ground Wa of the plate-like workpiece W1 may be set.

  After setting the reference load current value in this way, the plate-like workpiece W1 is continuously ground while measuring the thickness of the plate-like workpiece W1 with a thickness measuring means (not shown) until the set thickness is reached. During grinding of W1, the load current value detecting means 73 always monitors the change in grinding load applied to the motor 72. If the load current value of the motor 72 detected by the load current value detection means 73 has not reached the reference load current value, the electrode We is exposed to the surface to be ground Wa of the plate-like workpiece W1 by the determination unit provided in the determination means 30A. It is determined that it is not, and the determination result is sent to the control means 40A. As the control means 40A controls the grinding feed means 20A, the plate workpiece W1 is continuously ground until the load current value of the motor 72 reaches the reference load current value. On the other hand, when the load current value of the motor 72 detected by the load current value detection means 73 reaches the reference load current value, the determination unit provided in the determination means 30A causes the ground surface Wa in the recess 80 to be ground as shown in FIG. It is determined that the electrode We is exposed, and the determination result is sent to the control means 40A. Then, the control means 40A controls the grinding feed means 20A to raise the grinding means 70 and finish the grinding of the plate-like workpiece W1.

DESCRIPTION OF SYMBOLS 1,1A: Grinding device 100: Device base 101: Column 2, 2A: Holding table 2a: Holding surface 3: Frame 3a: Reference surface 4: Holding table rotating means 5: Cover 10: Grinding means 11: Grinding wheel rotating means 110 : Rotary shaft 111: Motor 112: Load current value detecting means 12: Holder 13: Housing 14: Mount 15: Grinding wheel 16: Grinding wheel 20, 20 A: Grinding feeding means 21: Ball screw 22: Motor 23: Guide rail 24: Elevating Plates 30 and 30A: Judgment means 31: Saving part 32: Setting part 33: Judgment part 40, 40A: Control means 50: Selection means 60: Thickness measurement means 61: First measuring instrument 61a: First measuring element 62 : Second measuring device 62a: second measuring element 63: calculating unit 70: grinding means 71: rotating shaft 72: motor 73: load current value detecting means 74 Mount 75: Grinding Wheel 76: grinding wheel 80: recess 81: protrusion

Claims (3)

A holding table having a holding surface for holding a plate-like workpiece having a plurality of electrodes therein, a holding table rotating means for rotating the holding table around the center of the holding table, and a grinding wheel provided in an annular shape A grinding means for grinding a plate-like workpiece held by the holding table by rotating the grinding wheel by the grinding wheel rotating means, the grinding wheel rotating means for rotating the grinding wheel about the rotating shaft by attaching the wheel to the rotating shaft; A grinding feed means for grinding and feeding the grinding means toward and away from the holding table; and a judgment for judging that the electrode is exposed on a surface to be ground of a plate-like workpiece to be ground by the grinding means. A grinding device comprising means,
The grindstone rotating means includes a motor for rotating the rotating shaft,
Load current value detecting means for detecting the load current value of the motor,
The determination means stores a load current value detected by the load current value detection means when the electrode inside the plate-like workpiece is not ground with the grinding wheel,
A setting unit that sets a value obtained by multiplying the load current value stored in the storage unit by a preset coefficient as a reference load current value when the electrode is exposed on the surface to be ground of the plate-like workpiece;
And a judgment unit that judges that the electrode is exposed on the surface to be ground when the load current value during grinding reaches the reference load current value set in the setting unit. A thickness measuring means for measuring the thickness of the plate-like workpiece to be ground by the grinding means;
The thickness measuring means includes a first measuring instrument for measuring the height of the holding surface by bringing a first measuring element into contact with the same surface as the holding surface outside the plate-like workpiece held by the holding table;
A second measuring instrument for measuring the height of the upper surface of the plate-shaped workpiece by bringing a second measuring element into contact with the upper surface of the plate-shaped workpiece held on the holding table;
A calculation unit that calculates the difference between the value of the first measuring instrument and the value of the second measuring instrument as the thickness of the plate-like workpiece,
A value greater than the height of the electrode is set in advance as a set thickness, and the plate-like workpiece is ground by the grinding means while the thickness of the plate-like workpiece is measured by the thickness measuring means until the set thickness is reached. The grinding apparatus according to claim 1, wherein the load current value detected by the load current value detection means is stored in the storage unit. Correlation data in which a coefficient is set according to the correlation between the type of the grinding wheel and the density of the plurality of electrodes provided in the plate-like workpiece,
3. The grinding apparatus according to claim 1, further comprising selection means for selecting the coefficient by referring to the correlation data in accordance with the type of the grinding wheel mounted on the rotating shaft and the density of the electrode of the plate workpiece.

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