JP2014159064A - Cutting blade detection mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting blade detection mechanism which can properly detect breakage of a cutting blade.SOLUTION: A cutting blade detection mechanism (6) for detecting the state of a cutting blade (41) is so configured that the mechanism (6) comprises: light emission means equipped with a first light-emitting body (62) having a circular light emission surface (62a) which has a diameter equal to or more than a tip first-out amount of a cutting edge (41b) extending from an annular support base (41a) of the cutting blade, and a second light-emitting body (63) having a circular light emission surface (63a) which has a diameter smaller than the tip first-out amount of the cutting edge; light-receiving means equipped with a first light-receiving body (64a) which is so disposed as to receive light from the first light-emitting body, and a second light-receiving body (65a) which is so disposed as to receive light from the second light-emitting body; and control means (68) which detects the state of the cutting edge on the basis of an amount of light irradiated from the light emission means onto the light-receiving means.

Description

  The present invention relates to a cutting blade detection mechanism that detects the state of a cutting blade mounted on a cutting device, and more particularly to a cutting blade detection mechanism that can appropriately detect breakage of a cutting blade.

  A wafer on which a plurality of devices are formed is cut by a cutting apparatus including a cutting blade, for example, and divided into a plurality of chips corresponding to each device. The cutting blade includes an annular base that is attached to a tip portion of a rotating spindle, and a cutting blade that is fixed to the outer periphery of the base. The cutting edge is formed by bonding abrasive grains such as diamond with a binding material, and the wafer is cut by rotating the cutting blade to cut the cutting edge into the wafer.

  In this cutting apparatus, the cutting edge is gradually worn by contact with a workpiece such as a wafer. Further, the cutting edge may be damaged due to a load during cutting. If you continue to use a cutting edge that has been worn or damaged beyond the allowable range, the workpiece may be damaged during the cutting process. Has been proposed (see, for example, Patent Document 1).

JP 2002-370140 A

  The cutting blade detection mechanism described in Patent Document 1 includes a light emitter that emits light and a light receiver that receives light emitted from the light emitter. The light emitter and the light receiver are arranged so as to sandwich the cutting blade, and at least a part of the light emitted from the light emitter is blocked by the cutting blade in a state where a cutting blade having no defect is mounted. ing. When the cutting edge is worn or broken, the blocked light reaches the photoreceptor and the amount of received light increases. Based on this increase in the amount of received light, a defect of the cutting edge can be detected. When a failure of the cutting edge is detected, the cutting blade is replaced.

  The above-described cutting blade detection mechanism determines the presence or absence of breakage such as chipping by comparing the amount of received light with a predetermined threshold, for example. However, the difference in the amount of light received before and after breakage is small when the cutting edge is short due to the thin blade thickness or when using a cutting edge with a short cutting edge, such as a cutting edge with advanced wear. Therefore, it is difficult to properly detect breakage of the cutting edge in comparison with the threshold value.

  This invention is made | formed in view of this point, and it aims at providing the cutting blade detection mechanism which can detect the failure | damage of a cutting blade appropriately.

  The cutting blade detection mechanism of the present invention is a rotating blade direction of a cutting blade having an annular cutting edge mounted on an annular support base for cutting a workpiece held on a chuck table that holds the workpiece. A light emitting means arranged on one side of the cutting blade, a light receiving means arranged on the other side in the rotational axis direction of the cutting blade so as to face the light emitting means and receiving light emitted by the light emitting means, and Control means for detecting the state of the cutting edge based on the amount of light received by the light receiving means, and the light emitting means comprises the cutting blade. A first light-emitting body having a circular light-emitting surface with a diameter equal to or greater than the leading edge of the cutting blade extended from the annular support base, and the cutting blade extended from the annular support base More than the tip of the cutting edge A second light-emitting body having a circular light-emitting surface having a thin diameter, and the light-receiving means includes a first light-receiving body disposed so as to receive light from the first light-emitting body, A second light receiving body arranged to receive light from the second light emitting body, and a photoelectric conversion unit for converting the amount of light received by the first light receiving body and the second light receiving body into a voltage, respectively. The light from the first light emitter is at a position covering the radial direction of the cutting edge extending from the annular support base, and the light from the second light emitter is on the cutting edge. The light emitting means and the light receiving means are positioned with respect to the cutting blade so as to be in the vicinity of the annular support base, and the control means corresponds to the amount of light received by the first light receiving body. When the received light voltage rises to the specified voltage, it is detected that the wear limit is reached, and corresponds to the amount of light received by the second photoreceptor. Receiving voltage to detect that the cutting blade is damaged when having intermittent or later peak value, characterized in that.

  According to this configuration, the cutting edge is formed by the first light emitting body having a circular light emitting surface having a diameter equal to or larger than the cutting edge of the cutting edge and the first light receiving body that receives light from the first light emitting body. The second light-emitting body having a circular light-emitting surface with a diameter smaller than the cutting edge amount of the cutting edge and the second light-receiving body that receives light from the second light-emitting body Since breakage is detected, breakage of the cutting edge can be appropriately detected even when a cutting edge with a short cutting edge is used.

  ADVANTAGE OF THE INVENTION According to this invention, the cutting blade detection mechanism which can detect the failure | damage of a cutting blade appropriately can be provided.

It is a perspective view showing an example of composition of a cutting device provided with a cutting blade detection mechanism concerning this embodiment. It is a perspective view which shows the periphery structure of a cutting means. It is a front view which shows the surrounding structure of a cutting means. It is the schematic diagram which looked at the surrounding structure of the cutting blade detection mechanism from the front side. It is the schematic diagram which looked at the periphery structure of the cutting blade detection mechanism from the side surface side. It is a graph which shows the example of the voltage output from a photoelectric conversion part before and after a cutting blade completely loses. It is a graph which shows the example of the voltage output from a photoelectric conversion part before and after a cutting blade completely loses.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view illustrating a configuration example of a cutting apparatus including a cutting blade detection mechanism according to the present embodiment. In the following, an example of the cutting apparatus will be described, but the configuration of the cutting apparatus including the cutting blade detection mechanism according to the present embodiment is not limited to this. The cutting device may have any configuration as long as the workpiece can be cut.

  As shown in FIG. 1, the cutting device 1 is configured so that a workpiece W held by a chuck table 3 on a housing 2 can be processed by a cutting means 4 provided above the chuck table 3. . The workpiece W is, for example, a semiconductor wafer or an inorganic material substrate, and has a disk-shaped outer shape. The surface of the workpiece W is partitioned into a plurality of regions by division lines arranged in a lattice pattern, and various devices 81 are formed in the partitioned regions. The workpiece W is supported by the annular frame 83 via the adhesive tape 82 and is carried into the cutting device 1 while being accommodated in the cassette 8.

  A rectangular opening (not shown) extending in the X-axis direction is formed on the upper surface of the housing 2. The opening is covered with a moving base 31 that moves together with the chuck table 3 and a bellows-shaped waterproof cover 32. A ball screw type moving mechanism (not shown) for moving the chuck table 3 in the X-axis direction is provided below the waterproof cover 32. On the upper surface of the chuck table 3, a holding surface 33 for sucking and holding the workpiece W is formed of a porous ceramic material. The holding surface 33 is connected to a suction source through a flow path provided inside the chuck table 3.

  The chuck table 3 reciprocates between a delivery position on the center side of the apparatus where the workpiece W is delivered and a machining position facing the cutting means 4. FIG. 1 shows a state in which the chuck table 3 stands by at the delivery position. In the housing 2, one corner portion adjacent to the delivery position is lowered by one step, and a placing table 7 is provided at a lowered position so as to be moved up and down. A cassette 8 that accommodates the workpiece W is placed on the placement table 7. As the mounting table 7 moves up and down, the drawing position and the pushing position of the workpiece W are adjusted in the Z-axis direction (height direction).

  A rear side of the mounting table 7 is provided with a pair of guide rails 9 parallel to the Y-axis direction, and a push-pull mechanism 10 that conveys the workpiece W between the pair of guide rails 9 and the cassette 8. Yes. The push-pull mechanism 10 pulls out the workpiece W before processing from the cassette 8 to the pair of guide rails 9 and pushes the processed workpiece W into the cassette 8 from the pair of guide rails 9. The workpiece W conveyed by the push-pull mechanism 10 is guided by the pair of guide rails 9, whereby the workpiece W is positioned in the X-axis direction. Further, the workpiece W is positioned in the Y-axis direction by controlling the movement amount of the push-pull mechanism 10.

  In the vicinity of the pair of guide rails 9, a first transfer arm 11 that transfers the workpiece W between the guide rails 9 and the chuck table 3 is provided. The 1st conveyance arm 11 is provided with the substantially L-shaped arm part 16, and the workpiece W is conveyed by this arm part 16 turning. Further, a spinner type cleaning mechanism 12 is provided behind the above-described delivery position. In the cleaning mechanism 12, cleaning water is sprayed toward the rotating spinner table 17, and the workpiece W is cleaned. The workpiece W after cleaning is dried with dry air sprayed in place of the cleaning water.

  A support base 21 that supports the cutting means 4 is provided on the housing 2. The cutting means 4 is positioned above the chuck table 3 and is moved in the Y-axis direction and the Z-axis direction by a ball screw type moving mechanism (not shown). The cutting means 4 includes a cutting blade 41 attached to the tip portion of a spindle (not shown). The periphery of the cutting blade 41 is covered with a wheel cover 42 or the like. In the wheel cover 42 and the like, a nozzle 51 (see FIGS. 2 and 3) for injecting cutting water toward the cutting portion and a cutting blade detection mechanism 6 (see FIGS. 2 to 5) for detecting the state of the cutting blade 41 are provided. Etc. are provided.

  A second transfer arm 13 for transferring the workpiece W between the chuck table 3 and the cleaning mechanism 12 is provided on the side surface 22 of the support base 21. The arm portion 18 of the second transfer arm 13 extends obliquely forward, and the workpiece W is transferred by moving the arm portion 18 back and forth. Further, the support base 21 is provided with a cantilevered support portion 24 so as to cross over the moving path of the chuck table 3. An imaging unit 14 that images the workpiece W is provided on the lower surface of the support unit 24. An image captured by the imaging unit 14 is used for alignment between the cutting unit 4 and the chuck table 3.

  At the foremost part of the housing 2, input means 26 is provided for receiving instructions to various parts of the apparatus. A monitor 27 is disposed on the upper surface of the support base 21. The monitor 27 displays an image captured by the imaging unit 14, the state of the cutting blade 41 detected by the cutting blade detection mechanism 6, the processing conditions of the workpiece W, and the like. The cutting apparatus 1 configured in this way cuts the workpiece W by rotating the cutting blade 41 and cutting it into the division line of the workpiece W. The state of the cutting blade 41 is detected in real time by the cutting blade detection mechanism 6.

  Next, details of the cutting blade detection mechanism will be described with reference to FIGS. 2 and 3 are a perspective view and a front view showing the peripheral structure of the cutting means, respectively. FIG. 4 is a schematic view of the peripheral structure of the cutting blade detection mechanism as viewed from the front side, and FIG. 5 is a schematic view of the peripheral structure of the cutting blade detection mechanism as viewed from the side.

  As shown in FIGS. 2 to 5, the cutting means 4 includes a cutting blade 41 attached to a tip portion of a rotatable spindle (not shown). The spindle is accommodated in a spindle housing 43, and a wheel cover 42 is mounted in front of the spindle housing 43. The outer periphery of the cutting blade 41 is covered with a wheel cover 42 and the like except for the lower part. The cutting blade 41 is fixed so as to be sandwiched between a flange 47 (FIG. 5) attached to the tip portion of the spindle and a ring-shaped fixing nut 48.

  The cutting blade 41 is a hub blade, and a cutting edge 41b for cutting the workpiece W is fixed to the outer periphery of the annular support base 41a. The cutting edge 41b is formed in an annular shape by bonding abrasive grains such as diamond with a bonding material, and has a thickness of about 10 μm to 500 μm, for example. In the present embodiment, a hub blade is exemplified as the cutting blade 41, but the type of the cutting blade 41 is not particularly limited. A washer blade or the like may be used as the cutting blade 41.

  A rear block 44 whose position can be adjusted in the Z-axis direction is provided behind the wheel cover 42 in the cutting direction. A pair of substantially L-shaped nozzles 51 sandwiching the lower portion of the cutting blade 41 are fixed to the rear block 44. Cutting water is supplied to the nozzle 51 through a connecting portion 52 provided at an upper portion of the rear block 44. A plurality of slits 53 (FIG. 3) facing the cutting blade 41 are formed on the tip side of the nozzle 51 extending forward in the cutting direction. The cutting point is cooled and cleaned by the cutting water sprayed through the plurality of slits 53.

  The rear block 44 is provided with a pair of splash covers 45 that guide cutting water to the rear in the cutting direction. The splash cover 45 guides the cutting water and the cutting waste scattered by the cutting to the rear in the cutting direction and discharges the cutting water 4 to the outside.

  A front block 46 is provided in front of the wheel cover 42 in the cutting direction. A supply hole (not shown) for supplying cutting water to the cutting edge 41b is formed on the rear surface of the front block 46 in the cutting direction. The supply hole is connected to a connecting portion 54 provided on the upper portion of the front block 46, and the cutting edge 41b is cooled and cleaned by cutting water supplied from the supply hole through the connecting portion 54. Further, on the lower surface of the front block 46, an injection hole (not shown) for injecting cutting water toward the adjacent line after cutting is formed. The injection hole is connected to a connecting portion 55 provided on the upper portion of the front block 46, and the adjacent line is cleaned by cutting water injected from the injection hole through the connecting portion 55.

  A cutting blade detection mechanism 6 is provided in the vicinity of the center of the wheel cover 42. The cutting blade detection mechanism 6 includes a portal-type support block 61 having two columnar portions 61 a and 61 b (FIGS. 4 and 5) sandwiching the upper portion of the cutting blade 41. A light emitting body (first light emitting body) 62 constituting a light emitting means of the cutting blade detection mechanism 6 and a light emitting body (second light emitting body) are provided on a surface of the columnar portion 61a facing the cutting edge 41b of the cutting blade 41. 63 is arranged. That is, the light emitting means includes the light emitters 62 and 63 disposed on the front side (one side in the rotation axis direction) of the cutting blade 41.

  Further, on the surface of the columnar portion 61b facing the cutting edge 41b of the cutting blade 41, a light receiving body (first light receiving body) 64 constituting a light receiving means of the cutting blade detection mechanism 6 and a light receiving body (second light receiving light). Body) 65 is arranged. That is, the light receiving means includes the light receiving bodies 64 and 65 disposed on the rear side (the other side in the rotation axis direction) of the cutting blade 41.

  The light emitter 62 includes a circular light emitting surface (circular light emitting surface) 62a having a diameter equal to or greater than the length of the cutting blade 41b (blade tip protruding amount) extending from the annular support base 41a. When the light emitting body 62 is viewed from the front side with the cutting blade 41 having no defect attached (FIG. 4), the upper portion of the light emitting surface 62a protrudes above the outer peripheral edge of the cutting edge 41b. That is, in front view, a part of the light emitter 62 is positioned radially inward from the outer peripheral edge of the cutting edge 41b, and the remaining part of the light emitter 62 is radially outward from the outer peripheral edge of the cutting edge 41b. Is positioned.

  On the other hand, the light emitter 63 includes a circular light emitting surface (circular light emitting surface) 63a having a diameter less than the length of the cutting edge 41b. When the light emitting body 63 is viewed from the front side with the cutting blade 41 having no defect, the light emitting surface 63a overlaps the cutting edge 41b. That is, in the front view, the light emitter 63 is positioned radially inward from the outer peripheral edge of the cutting edge 41b.

  The light emitters 62 and 63 are connected to a light source 66 through optical fibers 62b and 63b, respectively, and emit light guided from the light source 66 in a projection area corresponding to the light emitting surfaces 62a and 63a. Specifically, the light emitter 62 emits light so as to cover the radial direction of the cutting edge 41b extending from the annular support base 41a, and the light emitter 63 has an annular support base 41a of the cutting edge 41b. Light is emitted to a position in the vicinity of. The light emitters 62 and 63 may be self-luminous elements such as light emitting diodes. In this case, since the light emitters 62 and 63 function as a light source, the light source 66 and the like can be omitted. Further, the shape of the light emitting surfaces 62a and 63a is not limited to a circle. The light emitting means may include optical fibers 62b and 63b and a light source 66.

  The light receiving body 64 has a light receiving surface 64a having the same shape and size as the light emitting surface 62a, and is disposed at a position facing the light emitting body 62 with the cutting blade 41 interposed therebetween. That is, when viewed from the front, a part of the light receiving body 64 is positioned radially outward from the outer peripheral edge of the cutting edge 41b, and the remaining part of the light receiving body 64 is radially outward from the outer peripheral edge of the cutting edge 41b. Is positioned.

  The light receiving body 65 has a light receiving surface 65a having the same shape and size as the light emitting surface 63a, and is disposed at a position facing the light emitting body 63 with the cutting blade 41 interposed therebetween. That is, in the front view, the light receiver 65 is positioned on the radially inner side from the outer peripheral edge of the cutting edge 41b.

  The light receivers 64 and 65 are connected to the photoelectric conversion unit 67 via optical fibers 64b and 65b, respectively. The light received by the light receivers 64 and 65 is converted to a voltage according to the amount of light received by the photoelectric conversion unit 67. Converted. The light receivers 64 and 65 may be light receiving elements such as a CCD and a COMS. In this case, since photoelectric conversion is performed by the light receiving element, the photoelectric conversion unit 67 and the like can be omitted. Further, if the light emitted from the light emitters 62 and 63 can be received appropriately, the shape and size of the light receiving surfaces 64a and 65a are not necessarily equal to the light emitting surfaces 62a and 63a. The light receiving means may include optical fibers 64b and 65b and a photoelectric conversion unit 67.

  The light emission source 66 and the photoelectric conversion unit 67 are connected to a control unit 68 including a storage device, an arithmetic device, and the like. The control unit 68 controls the light emission of the light emission source 66 and detects the state of the cutting blade 41 based on the voltage supplied from the photoelectric conversion unit 67. Since the light emitter 62 and the light receiver 64 are configured as described above, at least a part of the light emitted from the light emitter 62 is blocked by the cutting edge 41b in a state where the cutting blade 41 having no defect is mounted. It does not reach the photoreceptor 64.

  When the cutting edge 41b is worn, the length of the cutting edge 41b is gradually shortened according to the wear amount. As a result, the light blocked by the cutting edge 41b reaches the light receiving body 64, and the amount of light received by the light receiving body 64 gradually increases. The control means 68 detects the wear of the cutting edge 41b based on the increase in the amount of light received by the photoreceptor 64. Specifically, the control means 68 determines the upper limit of the allowable amount of wear when the voltage supplied from the photoelectric conversion unit 67 rises to a predetermined threshold (voltage) corresponding to the amount of light received by the photoreceptor 64. It is determined that the wear limit has been reached.

  On the other hand, since the light emitter 63 and the light receiver 65 are positioned radially inward from the outer peripheral edge of the cutting edge 41b in a front view, the light emitter 63 radiates from the light emitter 63 in a state where the cutting blade 41 having no defect is mounted. All the light to be received is blocked by the cutting edge 41b and does not reach the photoreceptor 65. This state is maintained until the light emitter 63 protrudes from the outer peripheral edge in front view. That is, even if the cutting edge 41b is worn to some extent, the amount of light received by the photoreceptor 65 hardly changes.

  On the other hand, when the cutting edge 41b is damaged, the light blocked by the cutting edge 41b reaches the light receiver 65. For example, when damage such as chipping or cracking that reaches the vicinity of the light emitter 63 and the light receiver 65 occurs in the radial direction of the cutting edge 41b, light emitted from the light emitter 63 reaches the light receiver 65 through the damaged portion. Since the cutting blade 41 during rotation is rotating, the amount of light received by the light receiver 65 increases at the timing when the damaged portion passes near the light emitter 63 and the light receiver 65. That is, in this case, the amount of light received by the photoreceptor 65 takes an intermittent peak value.

  In addition, when damage (total loss) occurs such that the cutting edge 41b is lost, the light emitted from the light emitter 63 reaches the light receiving body 65 without being blocked by the cutting edge 41b. The amount increases. In this case, the amount of light received by the photoreceptor 65 increases at the timing of the total loss of the cutting edge 41b, and thereafter takes a peak value.

  The control means 68 detects the breakage of the cutting edge 41b based on the increase in the amount of light received by the photoreceptor 65. Specifically, the control means 68 indicates that damage such as chipping or cracking has occurred when the voltage supplied from the photoelectric conversion unit 67 has an intermittent peak value corresponding to the amount of light received by the photoreceptor 65. judge. Further, the control means 68 determines that the total loss has occurred when the voltage supplied from the photoelectric conversion unit 67 increases corresponding to the amount of light received by the photoreceptor 65 and has a peak value thereafter. The peak value is typically the maximum value of the voltage in an arbitrary period, but a voltage exceeding a predetermined threshold may be treated as the peak value.

  6 and 7 are graphs showing examples of voltages output from the photoelectric conversion unit before and after the cutting blade is completely damaged. FIG. 6 shows the voltage corresponding to the amount of light received by the light receiver 64, and FIG. 7 shows the voltage corresponding to the amount of light received by the light receiver 65.

As shown in FIG. 6, when cutting of the workpiece W progresses, the cutting edge 41 b of the cutting blade 41 wears, so that the voltage of the photoelectric conversion unit 67 corresponding to the amount of light received by the photoreceptor 64 is time-lapsed. It gradually grows with it. Since the cutting blade 41 is worn to some extent at time t ₁ and the length of the cutting edge 41b is shortened, even if the cutting blade 41 is completely damaged at this timing, the amount of light received by the photoreceptor 64 is as follows. It does n’t change much. That is, in this case, the voltage change ΔV ₁ due to the total loss is relatively small. Therefore, if it is attempted to appropriately detect the total loss of the cutting edge 41b with the light emitter 62 and the light receiver 64, it is necessary to adjust the threshold value for determination with high accuracy. Thus, although the light emitter 62 and the light receiver 64 are suitable for detecting wear, they are not suitable for detecting breakage.

On the other hand, as shown in FIG. 7, even if the cutting blade 41 is worn to some extent, the amount of light received by the photoreceptor 65 hardly changes. When total loss of the cutting blade 41 is generated at time t _1, the light receiving surface 65a of the photoreceptor 65 light emitted from the light emitter 63 are all incident amount of light received by the light receiving element 65 varies greatly. That is, in this case, the voltage change amount ΔV ₂ due to the total loss increases. As described above, the light emitter 63 and the light receiver 65 are not suitable for detecting wear, but are suitable for detecting breakage.

  As described above, the cutting blade detection mechanism 6 according to the present embodiment has a light emitting body (first light emitting surface) 62a having a circular light emitting surface (circular light emitting surface) 62a having a diameter equal to or larger than the length of the cutting edge 41b (blade tip protruding amount). One light emitter) 62 and a light receiver (first light receiver) 64 that receives light from the light emitter 62 detect wear of the cutting edge 41b and have a circular shape with a diameter smaller than the length of the cutting edge 41b. Breakage of the cutting edge 41b between the light emitting body (second light emitting body) 63 having the light emitting surface (circular light emitting surface) 63a and the light receiving body (second light receiving body) 65 that receives light from the light emitting body 63. Therefore, even when the cutting edge 41b with a short cutting edge is used, wear and breakage of the cutting edge 41b can be detected appropriately.

  In addition, since the light emitting body 62 and the light receiving body 64 for detecting wear are separated from the light emitting body 63 and the light receiving body 65 for detecting breakage, even if the threshold value for detecting the breakage is not adjusted accurately, Wear and breakage of the cutting edge 41b can be detected appropriately. That is, the working efficiency related to the maintenance of the cutting blade 41 can be increased.

  In addition, this invention is not limited to description of the said embodiment, A various change can be implemented. For example, in the above embodiment, the cutting blade detection mechanism including two sets of light emitters and light receivers has been described, but the cutting blade detection mechanism may include three or more sets of light emitters and light receivers. In addition, the configurations, methods, and the like according to the above-described embodiments can be changed as appropriate without departing from the scope of the present invention.

  The present invention is useful for appropriately detecting a failure occurring in a cutting blade.

DESCRIPTION OF SYMBOLS 1 Cutting device 4 Cutting means 6 Cutting blade detection mechanism 41 Cutting blade 41a Toroidal support base 41b Cutting edge 61 Support block 61a, 61b Columnar part 62 Light emitter (1st light emitter)
62a Light emitting surface (circular light emitting surface)
62b, 63b, 64b, 65b Optical fiber 63 Light emitter (second light emitter)
63a Light emitting surface (circular light emitting surface)
64 photoreceptor (first photoreceptor)
64a Light receiving surface 65 Light receiving body (second light receiving body)
65a Light-receiving surface 66 Light-emitting source 67 Photoelectric conversion unit 68 Control means

Claims (1)

The cutting blade having an annular cutting edge mounted on an annular support base for cutting the workpiece held on the chuck table holding the workpiece is disposed on one side in the rotational axis direction of the cutting blade. A light emitting means, a light receiving means disposed on the other side in the rotational axis direction of the cutting blade so as to face the light emitting means and receiving the light emitted by the light emitting means, and the light emitted from the light emitting means A control means for detecting the state of the cutting edge based on the amount of light received by the light receiving means, and a cutting blade detection mechanism of a cutting apparatus comprising:
The light-emitting means includes a first light-emitting body having a circular light-emitting surface having a diameter equal to or greater than a cutting edge amount of the cutting edge extended from the annular support base of the cutting blade, and the circle of the cutting blade. A second light-emitting body having a circular light-emitting surface with a diameter smaller than the blade tip extension amount of the cutting edge extending from the annular support base,
The light receiving means includes a first light receiving body arranged to receive light from the first light emitting body and a second light receiving body arranged to receive light from the second light emitting body. And a photoelectric conversion unit that converts the amount of light received by the first light receiver and the second light receiver into voltages, respectively,
The light from the first light emitter is in a position covering the radial direction of the cutting edge extending from the annular support base, and the light from the second light emitter is the annular support base of the cutting edge. The light emitting means and the light receiving means are positioned with respect to the cutting blade so as to be in the vicinity of the table,
The control means detects a wear limit when the received light voltage corresponding to the amount of light received by the first photoreceptor rises to a predetermined voltage,
Detecting that the cutting blade is damaged when the received light voltage corresponding to the amount of light received by the second photoreceptor has a peak value intermittently or thereafter;
A cutting blade detection mechanism.

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