JP7764136B2 - Spindle rotation speed measurement method and cutting device - Google Patents

Description

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.

The device chip manufacturing process uses a wafer on which devices are formed in multiple areas partitioned 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.

A cutting device is used to divide 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 has a spindle, the tip of which is fitted with an annular cutting blade that cuts the workpiece. The wafer is held on the chuck table, and the rotating cutting blade cuts into the wafer, cutting and dividing it (see Patent Document 1).

When cutting a workpiece with a cutting blade, a load is placed on the tip of the cutting blade that comes into contact with the workpiece, which can cause chipping at the tip of the cutting blade. Continuing to cut the workpiece with a chipped cutting blade can result in damage to the cutting blade or poor processing of the workpiece. Therefore, it is important to be able to detect chipped cutting blades quickly.

For this reason, cutting devices are sometimes equipped with a detection unit that detects the tip of the cutting blade and monitors the condition 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 positioned to sandwich the tip of the cutting blade. This optical detection means is positioned so that light traveling from the light-emitting unit to the light-receiving unit is blocked by the cutting blade.

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, causing an increase in 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.

JP 2010-129623 A Japanese Patent Application Laid-Open No. 2002-370140

When cutting a workpiece with a cutting device, the spindle rotation speed (cutting blade rotation speed) is set according to the workpiece's material and the processing details. However, when the cutting blade cuts into the workpiece, a load (processing load) is placed on the cutting blade depending on the workpiece's material, processing details, etc., and the spindle rotation speed may fluctuate. In this case, an error will occur 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.

For this reason, 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 using 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.

However, if a cutting unit is equipped with a measuring device that measures the rotation speed of the spindle, not only is it time-consuming and costly to prepare and install the measuring device, but the size of the cutting unit increases. In particular, if the cutting unit is equipped with a detection unit that detects the tip of the cutting blade, as mentioned above, it may be difficult to secure space within the cutting unit to install an additional measuring device.

The present invention was made in consideration of these 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 method for measuring the rotation speed of a spindle using such a cutting device.

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 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; and a measurement unit having a light-projecting portion and a light-receiving portion arranged to sandwich the insertion portion, and measuring the amount of light received by the light-receiving portion, wherein the cutting device does not have a dedicated measuring instrument for measuring the rotation speed of the spindle, and the spindle rotation speed measurement method includes: an attachment step of attaching a rotating member whose distance from the center of rotation to the outer periphery is not constant 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 of the rotating member inserted into the insertion portion without cutting a workpiece with the rotating member, and measuring the amount of light received; and a calculation step of calculating the rotation speed of the spindle based on the number of times the amount of light received measured in the measurement step shows a predetermined change within a predetermined measurement time.

Preferably, the spindle rotation speed measurement method further includes a correction step of correcting the rotation speed of the spindle so that it approaches a predetermined reference value for the rotation speed of the spindle based on a result of comparing the rotation speed calculated in the calculation step with the reference value for the rotation speed of the spindle.

According to another aspect of the present invention, there is provided a cutting device for cutting a workpiece, the cutting device comprising: 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; an insertion portion into which the tip of the cutting blade is inserted; a light-emitting portion and a light-receiving portion arranged to sandwich the insertion portion; a measurement unit measuring the amount of light received by the light-receiving portion; and a calculation portion calculating the number of rotations of the spindle; the cutting device does not have a dedicated measuring device for measuring the number of rotations of the spindle; a rotating member whose distance from the center of rotation to the outer edge is not constant can be attached to the mount portion; and the calculation portion calculates the number of rotations of the spindle based on the number of times the amount of light received measured by the measurement unit shows a predetermined change within a predetermined measurement time when the spindle is rotated while irradiating light from the light-emitting 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.

Preferably, the cutting device further includes a correction unit that corrects the rotation speed of the spindle to approach a predetermined reference value for the rotation speed of the spindle based on a result of comparing the rotation speed calculated by the calculation unit with the reference value .

In one aspect of the present invention, a measurement unit is used to calculate the rotation speed of the spindle. The measurement unit has an insertion section into which the tip of the cutting blade is inserted, and a light-emitting section and a light-receiving section that are positioned on either side of the insertion section. This makes it possible to monitor the condition 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.

FIG. FIG. 2A is a perspective view showing the cutting unit, and FIG. 2B is a partial cross-sectional side view showing the cutting unit. FIG. 2 is a block diagram showing a control unit and a measurement unit. FIG. 4A is a graph showing the change in the amount of received light when the non-circular member is rotated, and FIG. 4B is a graph showing the change in the amount of received light when the eccentric member is rotated. 10 is a flowchart showing a procedure for measuring the rotation speed of a spindle.

This embodiment will now be described with reference to the accompanying drawings. First, an example configuration of a cutting device according to this embodiment will be described. Figure 1 is a perspective view showing a cutting device 2. Note that in Figure 1, the X-axis direction (processing feed direction, left-right direction, first horizontal direction) and the Y-axis direction (indexing feed direction, front-back direction, second horizontal direction) are mutually perpendicular. Furthermore, the Z-axis direction (vertical direction, up-down direction, height direction) is a direction perpendicular to the X-axis and Y-axis directions.

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 top surface of the base 4 is provided above the base 4. A space (machining chamber) where 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 within the machining chamber.

The cutting unit 8 is fitted with an annular cutting blade 36, which is a tool used to cut the workpiece 11. The cutting unit 8 is also connected to a ball screw-type movement mechanism (not shown) that moves the cutting unit 8 along the Y-axis and Z-axis directions.

Below the cutting unit 8, a chuck table (holding table) 10 is provided to hold the workpiece 11. The upper surface of the chuck table 10 is a flat surface that is roughly parallel to the horizontal direction (XY plane direction), and forms 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.

A ball screw type movement mechanism (not shown) that moves the chuck table 10 along the X-axis direction is connected to the chuck table 10. The chuck table 10 is also connected to a rotational drive source (not shown), such as a motor, that rotates the chuck table 10 around a rotation axis that is generally parallel to the Z-axis direction.

A cassette mounting table 12 is installed at the front corner of the base 4. A cassette 14 capable of holding multiple workpieces 11 is placed on the top surface of the cassette mounting table 12. In addition, an elevation mechanism (not shown) is connected to the cassette mounting table 12, which moves (raises and lowers) the cassette mounting table 12 along the Z-axis direction. The elevation mechanism adjusts the height position (position in the Z-axis direction) of the cassette 14 so that workpieces 11 can be properly unloaded from and loaded into the cassette 14.

For example, the workpiece 11 is a disk-shaped wafer made of a semiconductor material such as silicon, with a front and back surface that are generally parallel to each other. The workpiece 11 is divided into multiple rectangular regions by multiple streets (planned division lines) arranged in a grid pattern that 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 side of each of the regions divided by the streets. When the cutting device 2 cuts and divides the workpiece 11 along the streets, multiple device chips each equipped with a device are produced.

However, there are no restrictions on the material, shape, structure, size, etc. of the workpiece 11. For example, the workpiece 11 may be a wafer (substrate) made of semiconductors other than silicon (GaAs, InP, GaN, SiC, etc.), sapphire, glass (quartz glass, borosilicate glass, etc.), resin, ceramics, metal, etc. Furthermore, there are no restrictions 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.

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 has a circular opening in the center that penetrates 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.

Tape 15 is attached to the workpiece 11 and the 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 also be an ultraviolet-curing resin that hardens when exposed to ultraviolet light.

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. The workpiece 11 is then stored in the cassette 14 while supported by the frame 13.

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

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

The display unit 16 may be a touch panel display. In this case, the display unit 16 functions as a user interface, allowing the operator to input information into 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 into the cutting device 2. However, the input unit may be provided separately from the display unit 16. In this case, a keyboard, mouse, etc. may be used as the input unit.

An alarm unit (alarm unit, alarm device) 18 that notifies the operator of information is provided on the top side of the cover 6. For example, an indicator light (warning light) is provided as the alarm unit 18. In this case, if an abnormality occurs in the cutting device 2, the indicator light will light up in a specified color or pattern to notify the operator of the abnormality. The alarm unit 18 can also be a speaker that notifies the operator of information by sound or voice. In this case, if an abnormality occurs in the cutting device 2, the speaker will emit a sound or voice to notify the operator of the abnormality.

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.

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

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 suction-held by the chuck table 10 via the tape 15.

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 and cutting into the workpiece 11. During cutting, a liquid (cutting fluid) such as pure water is supplied to the workpiece 11 and the cutting blade 36 at a predetermined flow rate. After machining, the workpiece 11 is transported by a transport mechanism and stored in a cassette 14.

Figure 2(A) is a perspective view showing the cutting unit 8, and Figure 2(B) is a partially cross-sectional side view showing the cutting unit 8. Note that for ease of explanation, the blade cover 42, described below, is not shown in Figure 2(B).

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

A mount 34 (see Figure 2(B)) is fixed to the tip of the spindle 32. The mount 34 has 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.

The cutting blade 36 may be, for example, a hub-type cutting blade (hub blade). A hub blade is composed of an annular base made of metal or the like, and an annular cutting edge formed along the outer edge of the base. The cutting edge of the hub blade is made 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-plated layer.

However, a washer-type cutting blade (washer blade) can also be used as the cutting blade 36. A washer blade consists solely of an annular cutting edge with abrasive grains fixed in place by a binder made of metal, ceramic, resin, etc.

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 threaded groove (not shown) is formed at the tip of the support shaft 34b, and a fixing nut 38 for fixing the cutting blade 36 is threaded into this threaded groove.

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. The cutting blade 36 can also be removed from the mount portion 34 by loosening the fixing nut 38 and removing it from the support shaft 34b.

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

A plate-shaped support member 40 is fixed to the tip of the housing 30. A box-shaped blade cover 42 (see Figure 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 connect to a tube (not shown) that supplies cutting fluid. The other end of the blade cover 42 is provided with a second connector 48 and a third connector 50 that connect to a tube (not shown) that supplies cutting fluid.

A pair of nozzles (cooler nozzles) 46 are connected to the pair of first connection parts 44, and are arranged to sandwich the lower end of the cutting blade 36. Each of the pair of nozzles 46 has a supply port (not shown) that opens toward the cutting blade 36. Cutting fluid supplied to the first connection 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.

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. 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.

A pair of nozzles (spray nozzles) 52 that open downward are connected to the third connection part 50. Cutting fluid supplied to the third connection part 50 flows into the nozzles 52 and is supplied from the tips of the nozzles 52 toward the chuck table 10 and workpiece 11 (see Figure 1).

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

A monitoring unit 54 is provided on the top 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. Inside the frame 56, a storage compartment 56a is provided that opens on the underside of the frame 56. The storage compartment 56a houses a measurement unit (detection unit) 58 that measures the amount of light and detects the tip of the cutting blade 36.

The measurement unit 58 has a nut portion (not shown), and a ball screw 60 arranged along the Z-axis direction is threaded onto 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 (raises and lowers) along the Z-axis direction, and the height position of the measurement unit 58 is adjusted.

Figure 3 is a block diagram showing the control unit 20 and the measurement unit 58. The measurement unit 58 is composed of 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 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 arranged 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 the insertion unit 64d into which the tip of the cutting blade 36 is inserted.

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

A photoelectric conversion unit 68 is connected to the light receiving unit 64c, which generates a signal corresponding to the amount of light received by the light receiving unit 64c (amount of received light). 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. This generates a signal corresponding to the amount of light received by the light receiving unit 64c.

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 section 64d. This positions the light-emitting section 64b and the light-receiving section 64c so that they 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-emitting section 64b toward the light-receiving section 64c.

When machining the workpiece 11 (see Figure 1), the cutting blade 36 is rotated and cuts into the workpiece 11 held by the chuck table 10 (see Figure 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 with an output shaft and a drive circuit that drives the motor. The motor's output shaft is connected to the spindle 32, and the rotation speed of the motor's 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.

In addition, while the cutting blade 36 is cutting the workpiece 11, light is emitted from the light-emitting element 64b toward the light-receiving element 64c, and the amount of light received by the light-receiving element 64c is measured. Here, if there is no chipping or wear at the tip of the cutting blade 36, the light emitted from the light-emitting element 64b is blocked by the tip of the cutting blade 36, and the amount of light received by the light-receiving element 64c is small.

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 that area and reaches the light-receiving unit 64c, increasing the amount of light received by the light-receiving unit 64c. Furthermore, 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 remain constant but will fluctuate.

Therefore, by measuring and monitoring the amount of light received by the light receiving element 64c, the condition 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 element 64c is generated by the photoelectric conversion element 68 and output to the control element 20. The control element 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 to determine 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.

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. In other words, 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 having to provide a separate measuring device for measuring the rotation speed of the spindle 32 independent of the measurement unit 58.

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 Figure 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 could also be used as the rotating member 72.

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

The rotating member 72 is a member whose distance from the center of rotation to its 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 unevenly worn, the outer periphery of the cutting blade 36 will become non-circular, and the cutting blade 36 can be used as a non-circular member.

The rotating member 72 can also be an eccentric member whose outer periphery is a perfect circle but whose center does not coincide with the center of rotation (center of the opening). Specifically, even if the cutting blade 36 is not chipped or worn, if the opening and outer periphery of the cutting blade 36 are not concentric, the cutting blade 36 will be attached to the mount 34 in an eccentric state and rotate. In this case, the cutting blade 36 can be used as an eccentric member.

After the rotating member 72 is attached to the cutting unit 8, the height position of the detection section 64 is adjusted and the tip (upper end) of the rotating member 72 is inserted into the insertion section 64d. This positions the tip of the rotating member 72 between the light-emitting section 64b and the light-receiving section 64c. Then, with light irradiated from the light-emitting section 64b toward the light-receiving section 64c, the spindle 32 rotates, causing the rotating member 72 to rotate around the rotation axis of the spindle 32.

While the rotating member 72 is rotating, the amount of light received by the light receiving unit 64c is measured. 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 signal generated by the photoelectric conversion unit 68 is then sequentially input to the control unit 20.

FIG. 4A is a graph showing the change in the amount of light received 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 portion 64b and the light-receiving portion 64c, light emitted from the light-emitting portion 64b passes through the recessed area of the rotating member 72 and reaches the light-receiving portion 64c, temporarily increasing the amount of light received by the light-receiving portion 64c. Therefore, when the amount of light received by the light-receiving portion 64c is measured for a certain period of time, peaks in the amount of light received (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.

4B is a graph showing the change in the amount of received light as the rotating member 72 (eccentric member) rotates. 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. 4B. The period _T2 of this waveform corresponds to the time it takes for the rotating member 72 to rotate once.

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 determine 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 determine the number of rotations of the spindle 32. Also, in FIG. 4(B), the number of rotations of the spindle 32 can be determined 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 its 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 its minimum value).

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 memory 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.). The memory unit 90 also stores information (data, programs, etc.) used for processing by the processing unit 80.

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 electrical signal (voltage) and sequentially outputs the electrical signal to the receiving unit 82. The receiving unit 82 then writes the electrical signal input from the photoelectric conversion unit 68 to a received light amount memory unit 92 included in the memory unit 90. As a result, the voltage transition corresponding to the amount of light received by the light receiving unit 64c is stored in the received light amount memory unit 92.

The processing unit 80 also includes a calculation unit 84 that calculates the rotation speed 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 memory unit 90 and reads out the information on the transition of the amount of received light (see Figures 4(A) and 4(B)) from the received light amount memory unit 92. The calculation unit 84 then calculates the rotation speed of the spindle 32 based on the transition of the amount of received light.

Specifically, the calculation unit 84 counts the number of times the amount of detected 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 memory 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.

The rotation speed of the spindle 32 calculated by the calculation unit 84 is output to the control signal generation unit 86. The control signal generation unit 86 then 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.

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 that causes the alarm unit 18 to issue an error notification, and outputs the control signal to the alarm unit 18. As a result, if the alarm unit 18 is an indicator light, the indicator light will light up in a predetermined color or pattern. Furthermore, if the alarm unit 18 is a speaker, a sound or voice will be emitted from the speaker to notify the user of the occurrence of an abnormality.

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

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. The correction unit 88 then corrects the rotation speed of the spindle 32 based on the results of comparing the calculated rotation speed with the reference rotation speed.

Specifically, the correction unit 88 first calculates the difference between the calculated rotation speed and the reference rotation speed, i.e., the difference (correction value) between the specified value (ideal value) and the actual measured value of the rotation speed of the spindle 32. The correction unit 88 then outputs a control signal to the rotary drive source 70 to increase or decrease the rotation speed of the spindle 32 by the correction value so that the rotation speed of the spindle 32 approaches the reference rotation speed. This reduces the error in the rotation speed of the spindle 32.

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. Figure 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 with a notch (recess) formed on its outer periphery is used as the rotating member 72 (non-circular member), mainly with reference to Figures 3 and 5.

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 clamping it between the flange portion 34a and the fixing nut 38.

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-emitting 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-emitting portion 64b and the light-receiving portion 64c.

Next, the cutting blade 36 is rotated by rotating the spindle 32 while irradiating light from the light-emitting unit 64b toward the light-receiving unit 64c. Then, the 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 light-receiving amount memory unit 92. As a result, information on the change in the amount of light received (see Figure 4(A)) is stored in the light-receiving amount memory unit 92.

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 memory unit 92 is read and input to the calculation unit 84. The calculation unit 84 then calculates the rotation speed of the spindle 32, for example, by counting the number of peaks in the amount of received light.

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) for 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, the correction unit 88 first 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).

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 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 rotary 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).

The spindle rotation speed measurement method described above is realized by the control unit 20 controlling the operation of each component of the cutting device 2. 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 that are output to each component of the cutting device 2 to execute the measurement step, calculation step, and correction step in sequence.

When measuring the rotation speed of the spindle 32, the control unit 20 reads and executes a program from the memory unit 90, outputting control signals to each component of the cutting device 2. This allows the measurement step, calculation step, and correction step to be carried out automatically.

The cutting device 2 may also be equipped with a blade changing device that replaces the cutting blade 36 attached to the mount 34 of the cutting unit 8 with 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.

As described above, in this embodiment, a measurement unit 58 having an insertion portion 64d into which the tip of the cutting blade 36 is inserted, and a light-emitting portion 64b and a light-receiving portion 64c arranged on either side of 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 installing a dedicated measuring device in the cutting unit 8.

The structures, methods, etc., described in the above embodiments can be modified as appropriate without departing from the scope of the present invention.

11 Workpiece 13 Frame 15 Tape 2 Cutting device 4 Base 6 Cover 6a Front surface 8 Cutting unit 10 Chuck table (holding table)
10a Holding surface 12 Cassette placement table 14 Cassette 16 Display section (display unit, display device)
18 alarm unit (alarm unit, alarm device)
20 control unit (control unit, control device)
30 Housing 32 Spindle 34 Mounting portion 34a Flange portion 34b Support shaft (boss portion)
36 Cutting blade 38 Fixing nut 40 Support member 42 Blade cover 44 First connecting portion 46 Nozzle (cooler nozzle)
48 Second connection part 50 Third connection part 52 Nozzle (spray nozzle)
54 Monitoring unit 56 Frame 56a Storage section 58 Measurement unit (detection unit)
60 Ball screw 62 Pulse motor 64 Detector 64a Base 64b Light emitter 64c Light receiver 64d Insertion section 66 Light source 68 Photoelectric converter 70 Rotational drive source 72 Rotating member 80 Processing section 82 Receiving section 84 Calculation section 86 Control signal generator 88 Correction section 90 Storage section 92 Received light amount storage section 94 Reference rotation number storage section

Claims (4)

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;
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 . The spindle rotation speed measurement method according to claim 1, further comprising a correction step of correcting the spindle rotation speed so that it approaches a predetermined reference value for the spindle rotation speed based on the result of comparing the rotation speed calculated in the calculation step with the reference value. 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. The cutting device of claim 3 further comprises a correction unit that corrects the rotation speed of the spindle so that it approaches a predetermined reference value for the rotation speed of the spindle based on the result of comparing the rotation speed calculated by the calculation unit with the reference value.