Spindle rotation speed measurement method and cutting device

Abstract

To provide a spindle rotation speed measurement method using a cutting device that can measure a rotation speed of a spindle without using a dedicated measuring instrument.SOLUTION: A spindle rotation speed measurement method measures a rotation speed of a spindle provided in a cutting device. The cutting device comprises: a cutting unit which has a spindle and a mount part, fixed to a tip part of the spindle, to which a cutting blade is detachably attached; and a measurement unit which has an insertion part into which a tip part of the cutting blade is inserted and a light projecting part and a light receiving part arranged to sandwich the insertion part and measures received light amounts by the light receiving part. The method includes: a mounting step of mounting a rotating member on the mount part; a measuring step of measuring the received light amounts by rotating the spindle while emitting light from the light projecting part toward the light receiving part, with a tip part of the rotating member inserted into the insertion part; and a calculating step of calculating a rotation speed of the spindle on the basis of a transition of the received light amounts measured in the measuring step.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cutting device that cuts a workpiece, and a spindle rotation speed measurement method that measures the rotation speed of a spindle provided in the cutting device. [Background technology]

[0002] The device chip manufacturing process uses a wafer in which devices are formed in multiple areas defined by multiple streets (planned division lines) arranged in a grid pattern. By dividing this wafer along the streets, multiple device chips, each equipped with a device, are obtained. The device chips are incorporated into various electronic devices, such as mobile phones and personal computers.

[0003] A cutting device is used to divide the wafers. The cutting device is equipped with a chuck table that holds the workpiece and a cutting unit that performs cutting on the workpiece. The cutting unit is equipped with a spindle, the tip of which is fitted with an annular cutting blade that cuts the workpiece. The wafer is held by the chuck table, and the rotating cutting blade cuts into the wafer, cutting and dividing the wafer (see Patent Document 1).

[0004] When cutting a workpiece with a cutting blade, a load is applied to the tip of the cutting blade that comes into contact with the workpiece, which can cause chipping at the tip of the cutting blade. If cutting of the workpiece continues while the cutting blade is chipped, there is a risk of the cutting blade being damaged or the workpiece being processed poorly. Therefore, it is necessary to quickly detect chipping in the cutting blade.

[0005] Therefore, cutting devices are sometimes equipped with a detection unit that detects the tip of the cutting blade and monitors the state of the cutting blade. For example, Patent Document 2 discloses a detection unit (optical detection means) that includes a light-emitting unit and a light-receiving unit that are arranged to sandwich the tip of the cutting blade. This optical detection means is arranged so that light traveling from the light-emitting unit to the light-receiving unit is blocked by the cutting blade.

[0006] If a chip occurs at the tip of the cutting blade while bonding the workpiece, the light emitted from the light-emitting unit reaches the light-receiving unit through the chip in the cutting blade, increasing the amount of light received by the light-receiving unit. Therefore, by monitoring the amount of light received by the light-receiving unit, it is possible to determine whether a chip has occurred at the tip of the cutting blade. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-129623 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-370140 Summary of the Invention [Problem to be solved by the invention]

[0008] When cutting a workpiece with a cutting device, the spindle rotation speed (cutting blade rotation speed) is set depending on the material of the workpiece and the processing details. However, when the cutting blade cuts into the workpiece, a load (processing load) is applied to the cutting blade depending on the material of the workpiece, the processing details, etc., and the spindle rotation speed may fluctuate. In this case, an error occurs between the spindle rotation speed input by the operator into the cutting device and the actual spindle rotation speed, and the workpiece will not be cut under the desired processing conditions.

[0009] Therefore, cutting units are sometimes equipped with a measuring device that measures the actual rotation speed of the spindle.The rotation speed of the spindle is measured by the measuring device built into the cutting unit, and the rotation speed of the spindle is corrected based on the measured value.This makes it possible to maintain the rotation speed of the spindle while cutting the workpiece.

[0010] However, if a measuring device for measuring the rotation speed of the spindle is installed in the cutting unit, it takes time and cost to prepare and install the measuring device, and the size of the cutting unit increases. In particular, if the cutting unit is equipped with a detection unit for detecting the tip of the cutting blade as described above, it may be difficult to secure space within the cutting unit to install an additional measuring device.

[0011] The present invention has been made in consideration of such problems, and aims to provide a cutting device that can measure the rotation speed of a spindle without using a dedicated measuring device, and a spindle rotation speed measurement method using the cutting device. [Means for solving the problem]

[0012] According to one aspect of the present invention, there is provided a spindle rotation speed measurement method for measuring the rotation speed of a spindle provided in a cutting device, the cutting device comprising: a cutting unit having the spindle and a mount portion fixed to a tip portion of the spindle and to which a cutting blade is detachably attached; an insertion portion into which the tip portion of the cutting blade is inserted; and a measurement unit having a light projecting portion and a light receiving portion arranged to sandwich the insertion portion, the measurement unit measuring the amount of light received by the light receiving portion, the cutting device not comprising a dedicated measuring instrument for measuring the rotation speed of the spindle, and comprising: an attachment step of attaching a rotating member having a variable distance from the center of rotation to the mount portion; a measurement step of rotating the spindle while irradiating light from the light projecting portion toward the light receiving portion with the tip portion of the rotating member inserted into the insertion portion without cutting a workpiece with the rotating member, and measuring the amount of light received; Within the specified measurement timeand calculating the rotation speed of the spindle based on the number of times a predetermined change is shown.

[0013] Preferably, the spindle rotation speed measuring method includes: calculating the rotation speed of the spindle based on a result of comparing a preset reference value of the rotation speed of the spindle with the rotation speed calculated in the calculating step; To approach the reference value The method further includes a correction step.

[0014] According to another aspect of the present invention, there is provided a cutting device for cutting a workpiece, the cutting device comprising: a spindle; a cutting unit having a mount portion fixed to a tip of the spindle and to which a cutting blade is detachably attached; an insertion portion into which the tip of the cutting blade is inserted; a light-projecting portion and a light-receiving portion arranged to sandwich the insertion portion; a measurement unit for measuring the amount of light received by the light-receiving portion; and a calculation portion for calculating the number of rotations of the spindle; the device does not include a dedicated measuring device for measuring the number of rotations of the spindle; a rotating member having a variable distance from the center of rotation to the outer periphery can be attached to the mount portion; and the calculation portion calculates the amount of light received measured by the measurement unit when the spindle is rotated while irradiating light from the light-projecting portion toward the light-receiving portion with the tip of the rotating member inserted into the insertion portion without cutting the workpiece with the rotating member; Within the specified measurement time A cutting device is provided that calculates the number of revolutions of the spindle based on the number of times a predetermined change is exhibited.

[0015] Preferably, the cutting device adjusts the rotation speed of the spindle based on a result of comparing a preset reference value of the rotation speed of the spindle with the rotation speed calculated by the calculation unit. To approach the reference value The image forming apparatus further includes a correction unit for performing the correction. [Effects of the Invention]

[0016] In one aspect of the present invention, a measurement unit having an insertion section into which the tip of the cutting blade is inserted and a light-emitting section and a light-receiving section arranged to sandwich the insertion section is used to calculate the rotation speed of the spindle. This makes it possible to monitor the state of the cutting blade and calculate the rotation speed of the spindle using the same measurement unit, and the rotation speed of the spindle can be calculated without installing a dedicated measuring device on the cutting unit. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. [Figure 2] FIG. 2(A) is a perspective view showing the cutting unit, and FIG. 2(B) is a partially cross-sectional side view showing the cutting unit. [Figure 3] FIG. 2 is a block diagram showing a control unit and a measurement unit. [Figure 4] FIG. 4(A) is a graph showing the change in the amount of received light when the non-circular member is rotated, and FIG. 4(B) is a graph showing the change in the amount of received light when the eccentric member is rotated. [Figure 5] 10 is a flowchart showing a procedure for measuring the rotation speed of a spindle. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, this embodiment will be described with reference to the accompanying drawings. First, an example of the configuration of a cutting device according to this embodiment will be described. FIG. 1 is a perspective view showing a cutting device 2. In FIG. 1, the X-axis direction (processing feed direction, left-right direction, first horizontal direction) and the Y-axis direction (indexing feed direction, front-rear direction, second horizontal direction) are perpendicular to each other. Furthermore, the Z-axis direction (vertical direction, up-down direction, height direction) is perpendicular to the X-axis direction and the Y-axis direction.

[0019] The cutting device 2 includes a base 4 that supports and houses each of the components that make up the cutting device 2. A cover 6 that covers the upper surface of the base 4 is provided above the base 4. A space (machining chamber) in which the workpiece 11 is machined is formed inside the cover 6, and a cutting unit 8 that performs cutting on the workpiece 11 is provided inside the machining chamber.

[0020] An annular cutting blade 36, which is a tool for cutting the workpiece 11, is attached to the cutting unit 8. In addition, a ball screw type movement mechanism (not shown) that moves the cutting unit 8 along the Y-axis direction and the Z-axis direction is connected to the cutting unit 8.

[0021] A chuck table (holding table) 10 that holds the workpiece 11 is provided below the cutting unit 8. The upper surface of the chuck table 10 is a flat surface that is roughly parallel to the horizontal direction (XY plane direction) and constitutes a holding surface 10a that holds the workpiece 11. The holding surface 10a is connected to a suction source (not shown) such as an ejector via a flow path (not shown), a valve, etc. formed inside the chuck table 10.

[0022] A ball screw type moving mechanism (not shown) that moves the chuck table 10 along the X-axis direction is connected to the chuck table 10. In addition, a rotation drive source (not shown) such as a motor that rotates the chuck table 10 around a rotation axis that is approximately parallel to the Z-axis direction is connected to the chuck table 10.

[0023] A cassette mounting table 12 is installed at a front corner of the base 4. A cassette 14 capable of accommodating a plurality of workpieces 11 is placed on the upper surface of the cassette mounting table 12. An elevation mechanism (not shown) that moves (lifts and lowers) the cassette mounting table 12 along the Z-axis direction is connected to the cassette mounting table 12. The elevation mechanism adjusts the height position of the cassette 14 (position in the Z-axis direction) so that the workpieces 11 can be appropriately carried out from and into the cassette 14.

[0024] For example, the workpiece 11 is a disk-shaped wafer made of a semiconductor material such as silicon, and has a front surface and a back surface that are generally parallel to each other. The workpiece 11 is divided into a plurality of rectangular regions by a plurality of streets (planned division lines) that are arranged in a grid pattern so as to intersect with each other. Furthermore, devices such as ICs (Integrated Circuits), LSIs (Large Scale Integration), LEDs (Light Emitting Diodes), and MEMS (Micro Electro Mechanical Systems) devices are formed on the front surface side of each of the regions divided by the streets. When the cutting device 2 cuts and divides the workpiece 11 along the streets, a plurality of device chips each equipped with a device are manufactured.

[0025] However, there are no limitations on the material, shape, structure, size, etc. of the workpiece 11. For example, the workpiece 11 may be a wafer (substrate) made of a semiconductor other than silicon (GaAs, InP, GaN, SiC, etc.), sapphire, glass (quartz glass, borosilicate glass, etc.), resin, ceramics, metal, etc. Furthermore, there are no limitations on the type, number, shape, structure, size, arrangement, etc. of devices, and the workpiece 11 does not necessarily have to have any devices formed on it. Furthermore, the workpiece 11 may be a package substrate such as a CSP (Chip Size Package) substrate or a QFN (Quad Flat Non-leaded package) substrate.

[0026] When the workpiece 11 is machined by the cutting device 2, the workpiece 11 is supported by an annular frame 13 for ease of handling (transporting, holding, etc.) the workpiece 11. The frame 13 is made of a metal such as SUS (stainless steel), and a circular opening is provided in the center of the frame 13, penetrating the frame 13 in the thickness direction. The diameter of the opening in the frame 13 is larger than the diameter of the workpiece 11, and the workpiece 11 is placed inside the opening in the frame 13.

[0027] Tape 15 is attached to workpiece 11 and frame 13. Tape 15 includes a circular film-like substrate and an adhesive layer (glue layer) provided on the substrate. For example, the substrate is made of a resin such as polyolefin, polyvinyl chloride, or polyethylene terephthalate. The adhesive layer is made of an epoxy-based, acrylic-based, or rubber-based adhesive. The adhesive layer may be an ultraviolet-curable resin that hardens when exposed to ultraviolet light.

[0028] When the center of the tape 15 is attached to the back (lower) surface of the workpiece 11 and the outer periphery of the tape 15 is attached to the frame 13, the workpiece 11 is supported by the frame 13 via the tape 15. Then, the workpiece 11 is housed in the cassette 14 while being supported by the frame 13.

[0029] A transport mechanism (not shown) for transporting the workpiece 11 is provided near the cassette mounting table 12. For example, the transport mechanism includes a plurality of suction pads that suction-hold the upper surface of the frame 13. The transport mechanism transports the unmachined workpiece 11 from the cassette 14 to the chuck table 10, and also transports the machined workpiece 11 from the chuck table 10 to the cassette 14.

[0030] A display section (display unit) 16 is provided on the front surface 6a side of the cover 6. The display section 16 is composed of various displays and displays information related to the cutting device 2. For example, the display section 16 can display an operation screen, the processing status, the processing conditions, an image of the workpiece 11, etc.

[0031] The display unit 16 may be a touch panel display. In this case, the display unit 16 functions as a user interface, and the operator can input information to the cutting device 2 by touching the display unit 16. In other words, the display unit 16 also functions as an input unit (input unit, input device) for inputting information to the cutting device 2. However, the input unit may be provided separately and independently from the display unit 16. In this case, a keyboard, a mouse, etc. can be used as the input unit.

[0032] An alarm section (alarm unit, alarm device) 18 that notifies the operator of information is provided on the upper surface side of the cover 6. For example, an indicator light (warning light) is provided as the alarm section 18. In this case, when an abnormality occurs in the cutting device 2, the indicator light lights up in a predetermined color or pattern to notify the operator of the abnormality. Alternatively, a speaker that notifies the operator of information by sound or voice can be used as the alarm section 18. In this case, when an abnormality occurs in the cutting device 2, the speaker emits a sound or voice to notify the operator of the abnormality.

[0033] Each component of the cutting device 2 (cutting unit 8, chuck table 10, cassette mounting table 12, display unit 16, notification unit 18, etc.) is connected to a control unit (control unit, control device) 20. The control unit 20 generates control signals that control the operation of each component of the cutting device 2, and controls the operation of the cutting device 2.

[0034] For example, the control unit 20 is configured by a computer. Specifically, the control unit 20 includes a processor such as a CPU (Central Processing Unit) that performs calculations necessary for the operation of the cutting device 2, and memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory) that store various information (data, programs, etc.) used for the operation of the cutting device 2.

[0035] The workpiece 11 stored in the cassette 14 is transported onto the chuck table 10 by the transport mechanism and held by the chuck table 10. Specifically, the workpiece 11 is placed on the holding surface 10a of the chuck table 10 via the tape 15. In this state, when the suction force (negative pressure) of the suction source is applied to the holding surface 10a, the workpiece 11 is sucked and held by the chuck table 10 via the tape 15.

[0036] The workpiece 11 held by the chuck table 10 is machined by the cutting unit 8. Specifically, the cutting unit 8 cuts the workpiece 11 by rotating the cutting blade 36 to cut into the workpiece 11. During the cutting process, a liquid (cutting fluid) such as pure water is supplied to the workpiece 11 and the cutting blade 36 at a predetermined flow rate. Then, after the processing, the workpiece 11 is transported by a transport mechanism and stored in a cassette 14.

[0037] Fig. 2(A) is a perspective view showing the cutting unit 8, and Fig. 2(B) is a partially cross-sectional side view showing the cutting unit 8. For ease of explanation, Fig. 2(B) omits the illustration of a blade cover 42, which will be described later.

[0038] The cutting unit 8 includes a cylindrical housing 30. The housing 30 accommodates a columnar spindle 32 (see FIG. 2(B)) arranged along the Y-axis direction. The tip (one end) of the spindle 32 is exposed from the housing 30. A rotation drive source (not shown), such as a motor, that rotates the spindle 32 is connected to the base (other end) of the spindle 32.

[0039] A mount 34 (see FIG. 2(B)) is fixed to the tip of the spindle 32. The mount 34 includes a disk-shaped flange 34a and a cylindrical support shaft (boss) 34b that protrudes from the center of the flange 34a. An annular cutting blade 36 that cuts the workpiece 11 is attached to the mount 34.

[0040] For example, a hub-type cutting blade (hub blade) is used as the cutting blade 36. A hub blade is composed of an annular base made of metal or the like, and an annular cutting edge formed along the outer periphery of the base. The cutting edge of the hub blade is composed of an electroformed grinding stone in which abrasive grains made of diamond, cubic boron nitride (cBN), or the like are fixed with a bonding material such as a nickel plating layer.

[0041] However, a washer-type cutting blade (washer blade) can also be used as the cutting blade 36. A washer blade is composed of only an annular cutting edge in which abrasive grains are fixed by a binder made of metal, ceramics, resin, or the like.

[0042] A cylindrical opening is provided in the center of the cutting blade 36, penetrating the cutting blade 36 in the thickness direction. The cutting blade 36 is attached to the mount 34 so that the support shaft 34b is inserted into the opening. A thread groove (not shown) is formed in the tip of the support shaft 34b, and a fixing nut 38 for fixing the cutting blade 36 is screwed into this thread groove.

[0043] When the fixing nut 38 is tightened into the thread groove of the support shaft 34b while the cutting blade 36 is supported by the mount portion 34, the cutting blade 36 is clamped between the flange portion 34a and the fixing nut 38 and attached to the mount portion 34. Also, the cutting blade 36 can be removed from the mount portion 34 by loosening the fixing nut 38 and removing it from the support shaft 34b.

[0044] In this way, the cutting blade 36 is detachably attached to the mount 34. The cutting blade 36 rotates around a rotation axis that is roughly parallel to the Y-axis direction by power transmitted from the rotation drive source via the spindle 32 and the mount 34.

[0045] A plate-shaped support member 40 is fixed to the tip of the housing 30. A box-shaped blade cover 42 (see FIG. 2(A)) that covers the cutting blade 36 is attached to the surface of the support member 40. One end of the blade cover 42 is provided with a pair of first connectors 44 that are connected to tubes (not shown) that supply cutting fluid. The other end of the blade cover 42 is provided with a second connector 48 and a third connector 50 that are connected to tubes (not shown) that supply cutting fluid.

[0046] A pair of nozzles (cooler nozzles) 46 are connected to the pair of first connecting parts 44 and are arranged to sandwich the lower end of the cutting blade 36. Each of the pair of nozzles 46 is provided with a supply port (not shown) that opens toward the cutting blade 36. The cutting fluid supplied to the first connecting parts 44 flows into the nozzles 46 and is supplied from the supply port of the nozzles 46 toward the front and back surfaces of the cutting blade 36.

[0047] A nozzle (shower nozzle, not shown) provided inside the blade cover 42 is connected to the second connection part 48. The tip of the shower nozzle opens toward the outer periphery of the cutting blade 36. The cutting fluid supplied to the second connection part 48 flows into the shower nozzle and is supplied from the tip of the shower nozzle toward the outer periphery of the cutting blade 36.

[0048] A pair of nozzles (spray nozzles) 52 that open downward are connected to the third connection part 50. The cutting fluid supplied to the third connection part 50 flows into the nozzles 52 and is supplied from the tip of the nozzles 52 toward the chuck table 10 and the workpiece 11 (see FIG. 1).

[0049] The cutting blade 36 is rotated and cuts into the workpiece 11 held by the chuck table 10 (see FIG. 1), thereby cutting the workpiece 11. During the cutting of the workpiece 11, cutting fluid is supplied to the workpiece 11 and the cutting blade 36 from the nozzle 46, shower nozzle (not shown), and nozzle 52. This cools the workpiece 11 and the cutting blade 36, and also washes away chips (cutting chips) generated by cutting the workpiece 11.

[0050] A monitoring unit 54 is provided on the upper part of the blade cover 42 to monitor the condition of the tip (cutting edge) of the cutting blade 36 attached to the cutting unit 8. As shown in FIG. 2(B), the monitoring unit 54 includes, for example, a rectangular parallelepiped frame 56. A storage section 56a that opens on the lower surface side of the frame 56 is provided inside the frame 56. A measurement unit (detection unit) 58 that measures the amount of light and detects the tip of the cutting blade 36 is stored in the storage section 56a.

[0051] The measurement unit 58 has a nut portion (not shown), and a ball screw 60 arranged along the Z-axis direction is screwed into this nut portion. A pulse motor 62 is connected to the upper end of the ball screw 60. When the ball screw 60 is rotated by the pulse motor 62, the measurement unit 58 moves (lifts and lowers) along the Z-axis direction, and the height position of the measurement unit 58 is adjusted.

[0052] FIG. 3 is a block diagram showing the control unit 20 and the measurement unit 58. The measurement unit 58 is configured with an optical sensor that measures the amount of light. Specifically, the measurement unit 58 includes a detection unit 64 that detects the tip of the cutting blade 36. The detection unit 64 has a rectangular parallelepiped base 64a and a light-emitting unit 64b and a light-receiving unit 64c that protrude downward from the base 64a. The light-emitting unit 64b and the light-receiving unit 64c are disposed to be spaced apart in the Y-axis direction and face each other. The space between the light-emitting unit 64b and the light-receiving unit 64c corresponds to an insertion section 64d into which the tip of the cutting blade 36 is inserted.

[0053] A light source 66 such as an LED is connected to the light-projecting unit 64b. Light emitted from the light source 66 is guided to the light-projecting unit 64b via an optical fiber or the like, and is irradiated from the light-projecting unit 64b toward the light-receiving unit 64c. The light irradiated from the light-projecting unit 64b reaches the light-receiving surface of the light-receiving unit 64c and is received by the light-receiving unit 64c.

[0054] A photoelectric conversion unit 68 that generates a signal corresponding to the amount of light received by the light receiving unit 64c (amount of received light) is connected to the light receiving unit 64c. The photoelectric conversion unit 68 includes a photoelectric conversion element that converts the light received by the light receiving unit 64c into an electrical signal (voltage). The light received by the light receiving unit 64c is guided to the photoelectric conversion unit 68 via an optical fiber or the like, and converted into an electrical signal by the photoelectric conversion unit 68. As a result, a signal corresponding to the amount of light received by the light receiving unit 64c is generated.

[0055] The measurement unit 58 monitors the condition of the tip of the cutting blade 36. Specifically, when the cutting blade 36 is attached to the cutting unit 8, the height position of the detection unit 64 is adjusted, and the tip (upper end) of the cutting blade 36 is inserted into the insertion portion 64d. This positions the light-projecting unit 64b and the light-receiving unit 64c so as to sandwich the tip of the cutting blade 36. At this time, the cutting blade 36 is positioned so as to block the light irradiated from the light-projecting unit 64b toward the light-receiving unit 64c.

[0056] When processing the workpiece 11 (see FIG. 1), the cutting blade 36 is rotated to cut into the workpiece 11 held by the chuck table 10 (see FIG. 1). A rotary drive source 70 that rotates the spindle 32 is connected to the spindle 32. For example, the rotary drive source 70 includes a motor including an output shaft and a drive circuit that drives the motor. The output shaft of the motor is connected to the spindle 32, and the rotation speed of the motor output shaft is controlled by the drive circuit. This controls the rotation speed of the spindle 32 (the rotation speed of the cutting blade 36) when cutting the workpiece 11.

[0057] Furthermore, while the cutting blade 36 is cutting the workpiece 11, light is emitted from the light-emitting portion 64b toward the light-receiving portion 64c, and the amount of light received by the light-receiving portion 64c is measured. If there is no chipping or wear at the tip of the cutting blade 36, the light emitted from the light-emitting portion 64b is blocked by the tip of the cutting blade 36, and the amount of light received by the light-receiving portion 64c is small.

[0058] On the other hand, if chipping or wear occurs at the tip of the cutting blade 36 and the chipped or worn area of ​​the cutting blade 36 is positioned between the light-emitting unit 64b and the light-receiving unit 64c, the light emitted from the light-emitting unit 64b passes through the area and reaches the light-receiving unit 64c, increasing the amount of light received by the light-receiving unit 64c. Also, if the cutting blade 36 is eccentric and the distance from the center of rotation of the cutting blade 36 to the outer periphery is not constant, the amount of light received by the light-receiving unit 64c will not be kept constant but will increase and decrease.

[0059] Therefore, by measuring and monitoring the amount of light received by the light receiving portion 64c, the state of the cutting blade 36 (presence or absence of chipping, wear, eccentricity, etc.) can be determined. Specifically, a signal corresponding to the amount of light received by the light receiving portion 64c is generated by the photoelectric conversion portion 68 and output to the control portion 20. The control portion 20 then compares the amount of light received measured by the measurement unit 58 with a preset reference value (threshold value) for the amount of light received, thereby determining whether the amount of light received is normal or abnormal. If the amount of light received is abnormal, cutting of the workpiece 11 by the cutting blade 36 is interrupted, and the cutting blade 36 is replaced.

[0060] Furthermore, in this embodiment, the rotation speed of the spindle 32 (the rotation speed of the cutting blade 36) is measured using the measurement unit 58. That is, the measurement unit 58 is used not only to monitor the state of the cutting blade 36 but also to measure the rotation speed of the spindle 32. This makes it possible to check the rotation speed of the spindle 32 without providing a measuring device for measuring the rotation speed of the spindle 32 separately and independently from the measurement unit 58.

[0061] When measuring the rotation speed of the spindle 32, a rotating member 72 is attached to the cutting unit 8. As an example, the following describes a case where the cutting blade 36 is used as the rotating member 72 (see FIG. 3). However, the rotating member 72 may be a member other than the cutting blade 36. For example, a disk-shaped member (inspection blade) made of a metal such as stainless steel and having a shape corresponding to the cutting blade 36 may be used as the rotating member 72.

[0062] A cylindrical opening penetrating the rotational member 72 in the thickness direction is provided in the center of the rotational member 72. The diameter of the opening in the rotational member 72 is set to be approximately the same as the diameter of the support shaft 34b of the mount portion 34. The rotational member 72 is attached to the mount portion 34 so that the support shaft 34b is inserted into the opening, and is fixed to the mount portion 34 by a fixing nut 38. When the spindle 32 is rotated in this state, the rotational member 72 rotates in conjunction with the spindle 32 around a rotation axis that is approximately parallel to the Y-axis direction.

[0063] The rotating member 72 is a member in which the distance from the center of rotation to the outer periphery is not constant. For example, a member whose outer periphery is not a perfect circle (a non-circular member) is used as the rotating member 72. Specifically, if a chip is formed on the outer periphery of the cutting blade 36 or if the outer periphery of the cutting blade 36 is worn unevenly, the outer periphery of the cutting blade 36 becomes non-circular, and the cutting blade 36 can be used as a non-circular member.

[0064] Furthermore, a member (eccentric member) whose outer circumferential edge is a perfect circle but whose center position does not coincide with the center of rotation (center of the opening) can also be used as the rotating member 72. Specifically, even if the cutting blade 36 is not chipped or worn, if the opening and the outer circumferential edge of the cutting blade 36 are not concentrically arranged, the cutting blade 36 is attached to the mount portion 34 in an eccentric state and rotates. In this case, the cutting blade 36 can be used as an eccentric member.

[0065] After the rotating member 72 is attached to the cutting unit 8, the height position of the detecting portion 64 is adjusted, and the tip (upper end) of the rotating member 72 is inserted into the inserting portion 64d. As a result, the tip of the rotating member 72 is positioned between the light-projecting portion 64b and the light-receiving portion 64c. Then, with light being irradiated from the light-projecting portion 64b toward the light-receiving portion 64c, the spindle 32 rotates, and the rotating member 72 rotates around the rotation axis of the spindle 32.

[0066] The amount of light received by the light receiving unit 64c is measured while the rotary member 72 is rotating. Specifically, the light received by the light receiving unit 64c is guided to the photoelectric conversion unit 68 and converted into an electrical signal (voltage) corresponding to the amount of light received. The electrical signals generated by the photoelectric conversion unit 68 are then sequentially input to the control unit 20.

[0067] FIG. 4A is a graph showing the change in the amount of received light as the rotating member 72 (a non-circular member) rotates. For example, if a recess (concave) is formed in one location on the tip of the rotating member 72, and the recessed area of ​​the rotating member 72 is positioned between the light-emitting unit 64b and the light-receiving unit 64c, light emitted from the light-emitting unit 64b passes through the recessed area of ​​the rotating member 72 and reaches the light-receiving unit 64c, temporarily increasing the amount of light received by the light-receiving unit 64c. Therefore, when the amount of light received by the light-receiving unit 64c is measured for a certain period of time, peaks in the amount of received light (voltage) appear at predetermined intervals, as shown in FIG. 4A. The period T1 of these peaks corresponds to the time it takes for the rotating member 72 to rotate once.

[0068] FIG. 4(B) is a graph showing the change in the amount of received light when the rotating member 72 (eccentric member) is rotated. When the rotating member 72 rotates in an eccentric state, the position of the upper end of the rotating member 72 changes continuously. Therefore, when the amount of received light by the light receiving unit 64c is measured for a certain period of time, a waveform is obtained in which the amount of received light (voltage) changes periodically, as shown in FIG. 4(B). The period T2 of this waveform corresponds to the time it takes for the rotating member 72 to rotate once.

[0069] Therefore, after measuring the amount of light received by the light receiving unit 64c for a certain period of time, the number of times the amount of light received shows a predetermined change can be counted to identify the number of rotations of the spindle 32 (the number of rotations of the rotating member 72) during the measurement period. For example, in FIG. 4(A), the number of peaks in the amount of light received can be counted, i.e., the number of times the amount of light received suddenly increases or decreases, to identify the number of rotations of the spindle 32. Also, for example, in FIG. 4(B), the number of rotations of the spindle 32 can be identified by counting the number of times the amount of light received changes from an increase to a decrease (the number of times the amount of light received reaches a maximum value) or the number of times the amount of light received changes from a decrease to an increase (the number of times the amount of light received reaches a minimum value).

[0070] The rotation speed of the spindle 32 can be calculated by the control unit 20 processing the signal generated by the photoelectric conversion unit 68. As shown in Fig. 3, the control unit 20 includes a processing unit 80 and a storage unit 90. The processing unit 80 processes information (signals, data, etc.) input from the outside, and generates and outputs various types of information (signals, data, etc.) to the outside. The storage unit 90 also stores information (data, programs, etc.) used in processing by the processing unit 80.

[0071] Specifically, the processing unit 80 includes a receiving unit 82 that receives a signal output from the photoelectric conversion unit 68. The photoelectric conversion unit 68 converts the light received by the light receiving unit 64c into an electric signal (voltage) and sequentially outputs the electric signal to the receiving unit 82. The receiving unit 82 then writes the electric signal input from the photoelectric conversion unit 68 into a received light amount storage unit 92 included in the storage unit 90. As a result, a transition in voltage corresponding to the amount of light received by the light receiving unit 64c is stored in the received light amount storage unit 92.

[0072] The processing unit 80 also includes a calculation unit 84 that calculates the number of rotations of the spindle 32. After the measurement of the amount of received light by the measurement unit 58 has continued for a predetermined period of time, the calculation unit 84 accesses the storage unit 90 and reads out transition information of the amount of received light (see FIGS. 4(A) and 4(B)) from the received light amount storage unit 92. The calculation unit 84 then calculates the number of rotations of the spindle 32 based on the transition of the amount of received light.

[0073] Specifically, the calculation unit 84 counts the number of times that the detected amount of received light shows a predetermined change within a predetermined measurement time. For example, the calculation unit 84 sequentially reads out the voltage values ​​stored in the received light amount storage unit 92, and counts the number of voltage peaks (the number of times the voltage suddenly increases or decreases), the number of times the voltage changes from an increase to a decrease, the number of times the voltage changes from a decrease to an increase, etc. This count value corresponds to the number of rotations of the spindle 32 within the predetermined measurement time.

[0074] The rotation speed of the spindle 32 calculated by the calculation unit 84 is output to the control signal generation unit 86. Then, the control signal generation unit 86 generates a control signal for displaying the calculated rotation speed of the spindle 32 on the display unit 16, and outputs the control signal to the display unit 16. As a result, the actual measured value of the rotation speed of the spindle 32 is displayed on the display unit 16.

[0075] Furthermore, if the rotation speed of the spindle 32 is outside the allowable range (abnormal value), the control signal generation unit 86 generates a control signal to cause the notification unit 18 to transmit an error, and outputs the control signal to the notification unit 18. As a result, if the notification unit 18 is an indicator light, the indicator light lights up in a predetermined color or pattern. Furthermore, if the notification unit 18 is a speaker, a sound or voice is emitted from the speaker to notify the occurrence of an abnormality.

[0076] Furthermore, the processing unit 80 includes a correction unit 88 that corrects the rotation speed of the spindle 32. The storage unit 90 also includes a reference rotation speed storage unit 94 that stores a reference value (reference rotation speed) of the rotation speed of the spindle 32. For example, the reference rotation speed storage unit 94 stores the desired rotation speed of the spindle 32 input as a processing condition, i.e., a specified value (ideal value) of the rotation speed of the spindle 32.

[0077] The correction unit 88 receives the rotation speed of the spindle 32 calculated by the calculation unit 84 (calculated rotation speed) and the reference rotation speed stored in the reference rotation speed storage unit 94. Then, the correction unit 88 corrects the rotation speed of the spindle 32 based on the result of comparing the calculated rotation speed with the reference rotation speed.

[0078] Specifically, correction unit 88 first calculates the difference between the calculated rotation speed and the reference rotation speed, that is, the difference (correction value) between the designated value (ideal value) and the actual measured value of the rotation speed of spindle 32. Then, correction unit 88 outputs a control signal to rotation drive source 70 to increase or decrease the rotation speed of spindle 32 by the correction value so that the rotation speed of spindle 32 approaches the reference rotation speed. This reduces the error in the rotation speed of spindle 32.

[0079] Next, a specific example of a spindle rotation speed measurement method for measuring the rotation speed of the spindle 32 provided in the cutting device 2 will be described. Fig. 5 is a flowchart showing the procedure for measuring the rotation speed of the spindle 32. As an example, the following describes a case where a cutting blade 36 having a notch (recess) formed on the outer periphery is used as a rotating member 72 (non-circular member), mainly with reference to Figs. 3 and 5.

[0080] First, the rotating member 72 (cutting blade 36) is attached to the mount portion 34 of the cutting unit 8 (attachment step, step S1). Specifically, the cutting blade 36, which has a notch on its outer periphery, is fixed to the mount portion 34 by being clamped between the flange portion 34a and the fixing nut 38.

[0081] Next, with the tip of the rotating member 72 (cutting blade 36) inserted into the insertion portion 64d, the spindle 32 is rotated while irradiating light from the light-projecting portion 64b toward the light-receiving portion 64c, and the amount of light received by the light-receiving portion 64c is measured (measurement step, step S2). In the measurement step, first, the pulse motor 62 (see FIG. 2(A)) is rotated by the ball screw 60, and the height position of the detection portion 64 is adjusted so that the tip (upper end) of the cutting blade 36 is positioned between the light-projecting portion 64b and the light-receiving portion 64c.

[0082] Next, while irradiating light from the light-emitting unit 64b toward the light-receiving unit 64c, the spindle 32 is rotated to rotate the cutting blade 36. Then, light received by the light-receiving unit 64c while the spindle 32 is rotating is converted into an electrical signal (voltage) by the photoelectric conversion unit 68. This measures the amount of light received by the light-receiving unit 64c. The measured amount of light received is then input to the receiving unit 82 of the processing unit 80 and written to the received light amount storage unit 92. As a result, transition information on the amount of light received (see FIG. 4(A)) is stored in the received light amount storage unit 92.

[0083] Next, the rotation speed of the spindle 32 is calculated based on the change in the amount of received light measured in the measurement step (calculation step, step S3). In the calculation step, information on the change in the amount of received light stored in the received light amount storage unit 92 is read out and input to the calculation unit 84. Then, the calculation unit 84 calculates the rotation speed of the spindle 32, for example, by counting the number of peaks in the amount of received light.

[0084] Next, the rotation speed of the spindle 32 is corrected (correction step) based on the result of comparing a preset reference value (reference rotation speed) of the rotation speed of the spindle 32 with the rotation speed of the spindle 32 calculated in the calculation step (calculated rotation speed). In the correction step, first, the correction unit 88 calculates the difference (correction value) between the calculated rotation speed input from the calculation unit 84 and the reference rotation speed input from the reference rotation speed storage unit 94, and determines whether the calculated rotation speed and the reference rotation speed match (step S4).

[0085] If the calculated rotation speed and the reference rotation speed match (YES in step S5), the spindle 32 is rotating at the desired rotation speed, and so the rotation speed of the spindle 32 is maintained (step S6). On the other hand, if the calculated rotation speed and the reference rotation speed do not match (NO in step S5), the correction unit 88 outputs a control signal to the rotation drive source 70 to increase or decrease the rotation speed of the spindle 32 by the correction value. This corrects the rotation speed of the spindle 32 (step S7).

[0086] The above-described spindle rotation speed measurement method is realized by controlling the operation of each component of the cutting device 2 with the control unit 20. Specifically, a program for causing the cutting device 2 to execute a measurement step, a calculation step, and a correction step is stored in the storage unit 90 (memory) of the control unit 20. This program includes instructions for causing the control unit 20 to generate control signals to be output to each component of the cutting device 2 in order to execute the measurement step, calculation step, and correction step in that order.

[0087] When measuring the rotation speed of the spindle 32, the control unit 20 reads out and executes a program from the storage unit 90, and outputs a control signal to each component of the cutting device 2. As a result, the measurement step, calculation step, and correction step are performed automatically.

[0088] The cutting device 2 may be equipped with a blade changing device that changes the cutting blade 36 attached to the mount 34 of the cutting unit 8 to the rotating member 72. In this case, the operation of the blade changing device is controlled by a control signal output from the control unit 20 to the blade changing device. Like the measurement step, calculation step, and correction step, the attachment step can also be performed automatically by executing a program.

[0089] As described above, in this embodiment, the measurement unit 58 having the insertion portion 64d into which the tip of the cutting blade 36 is inserted, and the light-emitting portion 64b and the light-receiving portion 64c arranged to sandwich the insertion portion 64d, is used to calculate the rotation speed of the spindle 32. This makes it possible to monitor the state of the cutting blade 36 and calculate the rotation speed of the spindle 32 using the same measurement unit 58, and the rotation speed of the spindle 32 can be calculated without newly installing a dedicated measuring device in the cutting unit 8.

[0090] The structures, methods, etc. according to the above-described embodiments can be modified as appropriate without departing from the scope of the object of the present invention. [Explanation of symbols]

[0091] 11 Workpiece 13 frames 15 Tape 2 Cutting equipment 4 Foundation 6 Cover 6a front 8 Cutting Unit 10 Chuck table (holding table) 10a Holding surface 12 Cassette stand 14 cassettes 16 Display unit (display unit, display device) 18. Alarm section (alarm unit, alarm device) 20 control unit (control unit, control device) 30 Housing 32 Spindle 34 Mounting section 34a Flange 34b Support shaft (boss part) 36 Cutting Blade 38 Fixing nut 40 Support member 42 Blade cover 44 First connection part 46 Nozzle (Cooler Nozzle) 48 Second connection part 50 Third connection part 52 Nozzle (spray nozzle) 54 Surveillance Unit 56 Frame 56a Storage section 58 Measurement unit (detection unit) 60 Ball screw 62 Pulse motor 64 Detector 64a base 64b Light projector 64c Light receiving part 64d Insertion section 66 Light source 68 Photoelectric conversion unit 70 Rotational drive source 72 Rotating member 80 Processing section 82 Receiving unit 84 Calculation Unit 86 Control signal generation unit 88 Correction Unit 90 Memory section 92 Received light amount storage section 94 Reference rotation speed memory section

Claims

1. A spindle rotation speed measurement method for measuring the rotation speed of a spindle provided in a cutting device, comprising: The cutting device is a cutting unit having the spindle and a mount portion fixed to the tip of the spindle and to which a cutting blade is detachably attached; a measuring unit having an insertion section into which the tip of the cutting blade is inserted, and a light emitting section and a light receiving section arranged to sandwich the insertion section, and measuring the amount of light received by the light receiving section; The cutting device does not include a dedicated measuring device for measuring the rotation speed of the spindle, a mounting step of mounting a rotating member having a non-uniform distance from a rotation center to an outer periphery on the mount portion; a measuring step of rotating the spindle while irradiating light from the light projecting unit toward the light receiving unit in a state where the tip of the rotating member is inserted into the insertion unit without cutting the workpiece with the rotating member, and measuring the amount of light received; a calculation step of calculating the rotation speed of the spindle based on the number of times the amount of received light measured in the measurement step shows a predetermined change within a predetermined measurement time.

2. 2. The spindle rotation speed measurement method according to claim 1, further comprising a correction step of correcting the rotation speed of the spindle so as to approach the reference value based on a result of comparing a predetermined reference value of the rotation speed of the spindle with the rotation speed calculated in the calculation step.

3. A cutting device for cutting a workpiece, a cutting unit having a spindle and a mount portion fixed to the tip of the spindle and to which a cutting blade is detachably attached; a measuring unit having an insertion portion into which the tip of the cutting blade is inserted, and a light emitting portion and a light receiving portion disposed so as to sandwich the insertion portion, the measuring unit measuring the amount of light received by the light receiving portion; a calculation unit that calculates the rotation speed of the spindle, There is no dedicated measuring device for measuring the rotation speed of the spindle, A rotating member having a non-constant distance from the rotation center to the outer periphery can be attached to the mount portion, the calculation unit calculates the number of rotations of the spindle based on the number of times the amount of received light measured by the measurement unit shows a predetermined change within a predetermined measurement time when the spindle is rotated while light is irradiated from the light-emitting unit to the light-receiving unit in a state where the tip of the rotating member is inserted into the insertion unit without cutting the workpiece with the rotating member.

4. The cutting device according to claim 3, further comprising a correction unit that corrects the rotation speed of the spindle so as to approach the reference value based on a result of comparing a preset reference value of the rotation speed of the spindle with the rotation speed calculated by the calculation unit.

Images