TW202027909A - Cutting device to sense the debris generated in the incision with good accuracy - Google Patents

Abstract

To sense the debris generated in the incision with good accuracy. The AE sensor (71) senses the elastic wave generated when the cutting tool (43) cuts the workpiece (W). The time characteristic data of the elastic wave signal sensed by the AE sensor (71) is Fourier-transformed by the analytical means (76) to obtain the frequency characteristic data. Next, specify the frequency band including the elastic wave generated by the cutting tool (43). In this frequency band, when the AE value of the elastic wave after Fourier transform exceeds the set first threshold value, the determination means (77) determines that debris has occurred.

Description

Cutting device

The present invention relates to a cutting device for cutting a workpiece.

A cutting device that cuts a workpiece held on a suction table with a cutting blade provides cutting water to the cutting blade while bringing the cutting blade into contact with the workpiece to cut the workpiece. In the cutting process, due to blockage, dullness, chipping, etc. of the cutting tool, or the setting error of the cutting feed rate, the cutting tool vibrates more than usual, which may cause chipping on the surface of the workpiece. .

Therefore, in order to sense the generated chips, as disclosed in Patent Document 1 and Patent Document 2, there is a technique that uses an AE sensor to sense the vibration of the cutting tool during cutting. AE value) exceeds the threshold, that is, it is judged that chipping occurs in the workpiece. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] JP 2015-170745 A [Patent Document 2] Japanese Patent Application Publication No. 2018-117092

(The problem to be solved by the invention)

However, in the detection of the vibration of the cutting tool by the inventions shown in Patent Document 1 and Patent Document 2 shown above, when an abnormal vibration is detected that is considered to occur in the cutting tool, etc., it is sometimes used. No debris was found when observing the incision with an electron microscope. In this case, the threshold value for determining the magnitude of the vibration of the cutting tool where chipping occurs is set to be too small. Although chipping does not actually occur, it is erroneously sensed that chipping occurs. On the other hand, if the threshold for determining the magnitude of the vibration of the cutting tool where chipping occurs is raised, this time even chipping cannot be sensed. As shown above, in the process of judging whether chipping occurs according to the magnitude of the sensed vibration of the cutting tool, a problem occurs in the appropriate selection of the means for vibration sensing or the threshold of vibration. The problem to be solved by the present invention is to sense the vibration of the cutting tool so as to more accurately sense the debris generated in the incision. (Means to solve the problem)

The present invention is a cutting device comprising: holding means for holding a workpiece; cutting means provided with a cutting blade for cutting the workpiece held by the holding means; and cutting water for supplying cutting water to the cutting blade Feeding means; cutting and feeding means that move the cutting blade and the holding means in the cutting feed direction; it is arranged on the cutting means or the holding means and senses what happens to the cutting tool by cutting An AE sensor for elastic waves; and a cutting device for a control means. The control means is: the AE sensor is used to sense the elastic waves containing complex frequency components that are generated when the cutting tool cuts the workpiece. The elastic wave signal sensed by the AE sensor is Fourier transformed to specify the frequency band of the elastic wave signal generated by the cutter. In the specific frequency band, the elastic wave signal is Fourier transformed to a value Exceeding the preset first threshold value, that is, it is judged that chipping occurs in the cut of the workpiece by the cutting tool and there is an abnormality in the cutting process.

The control means included in the above-mentioned cutting device preferably obtains the average value of the value obtained by Fourier transforming the elastic wave signal for each frequency band, and obtains the characteristic value from the average value of the complex number within a predetermined time, the Once the characteristic quantity exceeds the preset second threshold value, it is determined that chipping occurs in the cut of the workpiece by the cutting tool and there is an abnormality in the cutting process.

The control means included in the cutting device is preferably such that the number of times that the characteristic quantity exceeds the preset third threshold value exceeds the preset number of times, that is, it is determined that chipping occurs in the incision of the cutting tool to cut the workpiece and There is an abnormality in the cutting process. (Effect of Invention)

The AE sensor is used to sense the elastic wave generated by the load applied to the cutting tool along with the cutting process, and the sensed elastic wave signal is Fourier-transformed, and whether the Fourier-transformed AE value of each frequency band is Exceeding the preset threshold value of the elastic wave AE value, it can be judged that the sensing chip occurs and there is an abnormality in the cutting process. By this, the cutting device is controlled to perform appropriate measures such as interruption of cutting, and the occurrence of defective wafers can be prevented.

1 Composition of cutting device

As shown in FIG. 1, the cutting device 1 is a cutting device that cuts the cutting blade 43 included in the cutting means 40 to the surface Wa of the workpiece W held by the holding means 15 and cuts the workpiece W. The cutting device 1 shown in FIG. 1 is a double cutter provided with two cutting means 40, but the cutting device is not limited to this, and it may be a cutting device provided with one cutting means. Each element D is provided in the area divided by the planned dividing line L formed on the surface Wa of the workpiece W, etc., which is the semiconductor wafer, and the cutting blade 43 can be cut along the planned dividing line L. The workpiece W is divided into individual elements D. An adhesive tape T is attached to the back Wb of the workpiece W, and the end of the adhesive tape T attached to the workpiece W is attached to the ring frame F, and the workpiece W is supported In frame F. The cutting device 1 is equipped with a base 10 and a door-shaped column 13 erected on the base 10 on the -X side.

The center above the base 10 is equipped with a circular plate-shaped platform that is a holding means 15, a cover 11 surrounding the holding means 15 from below, and a bellows cover 12 connected to the cover 11. The holding means 15 includes a suction portion 150 and a frame 151 that supports the suction portion 150. The upper surface of the suction portion 150 serves as a holding surface 150a on which the workpiece W is placed. A suction means 80 is arranged below the holding means 15, and the holding surface 150a is connected to the suction means 80. In the state where the workpiece W is placed on the holding surface 150a, the suction force generated by the suction means 80 is transmitted to the suction part 150, whereby the workpiece W can be sucked and held on the holding surface 150a.

In addition, four clamps 17 are arranged at positions adjacent to the holding means 15 surrounded by the holding means 15 in four directions, and the workpiece W supported by the ring frame F is placed on the holding surface 150a, and four The jig 17 clamps the frame F in four directions, whereby the workpiece W can be fixed to the holding means 15. In addition, a bottomed cylindrical housing 83 is connected to the lower side of the holding means 15, and a rotating means 81 that rotates the holding means 15 around a rotating shaft 82 in the Z-axis direction is arranged inside the housing 83.

The inside of the base 10 is equipped with the cassette storage area 20 which accommodates and holds the to-be-processed object W a cassette which is not shown in figure. The upper surface of the cassette accommodating area 20 serves as a stage 22, and the stage 22 on which the cassette holding the workpiece W is placed is moved up and down by the cassette lifting means 21 to adjust the height of the cassette.

On the base 10, a cleaning means 24 is arranged at a position facing the cassette lifting means 21 with the holding means 15 interposed therebetween. The washing means 24 is equipped with a spinner platform 25 and a washing water nozzle 26. The rotator platform 25 holding the workpiece W is lowered to the inside of the base 10 by the lifting means not shown, and the rotator platform 25 can be rotated by the rotating means not shown while washing The water nozzle 26 sprays washing water, thereby washing the workpiece W. In addition, after washing the workpiece W, the spray of washing water is stopped, and then the workpiece W is rotated, whereby the water droplets adhering to the surface Wa are sprayed toward the outside of the surface Wa. Thereby, the surface Wa of the workpiece W can be dried.

A cutting and feeding means 18 is arranged inside the base 10. The cutting and feeding means 18 includes: a ball screw 180 having a rotating shaft 184 in the X-axis direction; a pair of guide rails 181 arranged in parallel with the ball screw 180; a motor 182 connected to one end of the ball screw 180; and an internal nut The structure is screwed on the ball screw 180 and the bottom is slidably connected to the movable plate 183 of the guide rail 181. In addition, the movable plate 183 supports the holding means 15 through the housing 83. When the ball screw 180 is driven by the motor 182 to rotate around the rotating shaft 184 in the X-axis direction, the movable plate 183 is guided by the guide rail 181 to move in the X-axis direction, that is, in the cutting feed direction. 83 and the holding means 15 supported by the movable plate 183 moves in the X-axis direction together with the movable plate 183. Wherein, when the holding means 15 moves in the X-axis direction, the cover 11 surrounding the holding means 15 moves integrally with the holding means 15 in the X-axis direction. If the cover 11 moves in the X-axis direction, the accordion cover 12 will expand and contract.

Two cutting means 40 are respectively arranged on the left and right side walls of the door-shaped column 13. The two cutting means 40 have the same configuration, and their constituent elements are marked with the same symbols.

The cutting means 40 is equipped with a cutting blade 43, a mandrel 42 supporting the cutting blade 43, and a square cylindrical mandrel housing 41 that houses the mandrel 42. A knife cover 45 is attached to the spindle housing 41. The central part of the blade cover 45 is provided with an opening for mounting the cutting blade 43 to cover the area from the upper side of the outer peripheral edge of the cutting blade 43 to the side. In addition, the lower part of the knife cover 45 is movably mounted with a nozzle that supplies cutting water to the cutting blade 43 or the part where the workpiece W is in contact with the cutting blade 43 when the workpiece W is cut. When cutting water supply means 46, the cutting water supply means 46 is supplied by a cutting water supply source (not shown) while cutting water supply means 46 contact the cutting blade 43 or the workpiece W and the cutting blade 43 While supplying cutting water to the part of, the workpiece W is cut.

As shown in FIGS. 2 and 3, a cover member 47 covering the front end side of the spindle 42 is attached to the front end surface 41 a of the spindle housing 41. The cover member 47 is provided with a pair of brackets 48. With the front end portion of the spindle 42 protruding from the opening 49 of the cover member 47, the cover member 47 is screwed to the spindle housing through the bracket 48 The body 41, the cover member 47 and the spindle 42 are connected.

The tool holder base 51 includes a disc-shaped flange portion 56 and a sleeve portion 53 formed on the surface 56 a (-Y direction side) of the flange portion 56. On the back surface 56b (+Y direction side) of the flange part 56, as shown in FIG. 3, the fitting hole 52 installed in the front end of the spindle 42 is formed. A circular recess 54 is formed in the sleeve portion 53, and a through hole 55 connected to the fitting hole 52 is formed on the bottom surface of the circular recess 54. In the state where the front end surface 42a of the spindle 42 is exposed from the through hole 55 of the tool holder base 51, the spindle 42 is inserted into the tool holder base 51, and the fixing bolt 59 is fastened to the front end surface 42a of the spindle 42 through the washer 58 Through the screw hole 44, the tool holder base 51 is fixed to the spindle 42.

The cutting blade 43 is equipped with a hub base 61 that is circular, and a cutter 62 annularly arranged on the outer peripheral edge of the hub base 61. The hub base 61 has an insert formed on the inner side of the circle.孔63. The insertion hole 63 is press-fitted into the sleeve portion 53, and the sleeve portion 53 protrudes from the hub base 61. Next, the fixing nut 65 is fastened to the male screw portion 57 formed in the protruding portion of the sleeve portion 53 to fix the cutting blade 43 to the tool holder base 51.

The cutter 62 is formed into a predetermined thickness by mixing diamond or CBN particles with a bonding material such as metal or resin. Among them, the cutting blade 43 may also use a washer-type blade composed of only the cutting blade 62.

As shown in FIG. 3, the flange portion 56 of the tool holder base 51 is provided with an AE sensor 71. The AE sensor 71 has a piezoelectric element, which can convert the elastic wave generated by the cutter 43 and transmitted to the tool holder base 51 during cutting into an electrical detection signal, that is, an elastic wave signal for output.

In the boundary area between the tool holder 51 and the cover member 47, the AE sensor 71 is connected to the first coil means 73 on the tool holder 51 side, and the first coil means 73 is connected to the cover member 47 side. The second coil means 74 is connected. If the elastic wave is sensed by the AE sensor 71, the elastic wave signal is transmitted to the first coil means 73 by the AE sensor. In addition, the first coil means 73 is transmitted by the magnetic mutual induction. To the second coil means 74.

The control means 75 is connected to the second coil means 74 magnetically coupled to the first coil means 73. The control means 75 is equipped with: analysis means 76 for frequency analysis of the time axis waveform detected by the AE sensor 71; and judgment means 77 for judging whether debris is formed based on the result of the frequency analysis. After the elastic wave signal detected by the AE sensor 71 is transmitted to the control means 75 through the first coil means 73 and the second coil means 74, the time axis waveform is Fourier converted by the analysis means 76 and converted into frequency Axis waveform.

In addition, the control means 75 is equipped with a notification means 78 for notifying the operator or the like of the fact when it is determined that debris has occurred by the determination means 77.

As shown in FIG. 1, the gate-shaped column 13 is equipped with a stepping feed means 30 and a cutting feed means 35 that move the two cutting means 40 configured as described above in the Y-axis direction and the Z-axis direction, respectively.

The classifying feeding means 30 is equipped with a ball screw 33 having an axis in the Y-axis direction, a motor 34 that rotates the ball screw 33 around a rotating shaft 330 parallel to the Y-axis, and is arranged in parallel with the ball screw 33 The guide rail 31 and the nut on the side are screwed to the ball screw 33 and slidably connected to the movable plate 32 of the guide rail 31. When the ball screw 33 is driven by the motor 34 and the ball screw 33 rotates around the rotating shaft 330, the movable plate 32 is guided by the guide rail 31 to move in the Y-axis direction.

In addition, the cutting and feeding means 35 is provided with a ball screw 38 having an axis in the Z-axis direction, a motor 39 that rotates the ball screw 38 around a rotating shaft 380 parallel to the Z-axis, and parallel to the ball screw 38 The arranged guide rail 36 and the nut on the side are screwed to the ball screw 38 and slidably connected to the support member 37 of the guide rail 36. When the ball screw 38 is driven by the motor 39 to rotate, the support member 37 is guided by the guide rail 36 to move in the Z-axis direction.

A spindle housing 41 is connected to the lower end of the support member 37. When the support member 37 moves in the Y-axis direction and the Z-axis direction, the cutting means 40 moves in the Y-axis direction and the Z-axis direction in the same manner.

An alignment means 9 is arranged on the side surface of the spindle housing 41. The alignment means 9 is provided with a camera 90 that captures images of the workpiece W. The camera 90 includes, for example, a light irradiating section that irradiates the workpiece W with light, an optical system that captures reflected light from the workpiece W, and An imaging element (CCD) that outputs electrical signals corresponding to reflected light. The aligning means 9 can detect the planned dividing line L of the workpiece W to be cut based on the image obtained by the camera 90. The aligning means 9 and the cutting means 40 are formed integrally, and they move in the Y-axis direction and the Z-axis direction in conjunction with each other. 2 Movement of the cutting device

(Cutting) The operation of the cutting device 1 when the workpiece W is cut by the cutting device 1 described above will be described. Among them, the sticking tape T is attached to the workpiece W. In this state, the sticking tape T is held by the ring frame F, whereby the workpiece W is fixed by the frame F.

First, in the cassette storage area 20, the cassette 22 is raised by the cassette lifting means 21, and the cassette on which the workpiece W fixed to the frame F is placed is positioned above the base 10, and then borrowed The ring frame F is held by an arm or the like, not shown, and placed on the holding surface 150a of the holding means 15, so that the attractive force generated by the suction means 80 is transmitted to the holding surface 150a and on the holding surface 150a The object W to be processed is sucked up and held. Next, the frame F is clamped by four clamps 17 to fix it.

After that, the ball screw 180 is rotated about the rotating shaft 184 by the driving force of the motor 182 of the cutting and feeding means 18, whereby the movable plate 183 and the holding means 15 supported by the movable plate 183 are moved along the guide rail 181- It moves in the X direction, and the workpiece W attracted and held by the holding means 15 is positioned below the aligning means 9. After the workpiece W is positioned below the alignment means 9, the surface Wa of the workpiece W is imaged by the camera 90. The image of the surface Wa of the workpiece W captured by the camera 90 is subjected to image processing such as pattern matching by the alignment means 9 to detect the planned dividing line L into which the two cutters 43 should be cut.

Along with the detection of the planned dividing line L by the aligning means 9, the cutting means 40 is driven in the Y-axis direction by the step feed means 30 to align the planned dividing line L to be cut with the cutting blade 43 in the Y-axis direction . In the alignment between the planned dividing line L and the Y-axis direction of the cutting blade 43, based on the pattern matching result described above, the ball screw 33 is rotated around the rotating shaft 330 by the motor 34 of the grading feeding means 30, and accordingly, it is movable The plate 32 moves in the Y-axis direction along the guide rail 31, and the support member 37 connected to the movable plate 32 and the cutting means 40 supported by the support member 37 move in the Y-axis direction.

After the alignment in the Y-axis direction is completed, the spindle 42 of the cutting means 40 is rotated by a motor not shown, and the cutting blade 43 connected to the spindle 42 is rotated. In the state where the cutting blade 43 is rotating, the ball screw 38 is driven by the motor 39 of the cutting feed means 35 to rotate the ball screw 38 around the rotating shaft 380, and the cutting blade 43 is lowered in the Z-axis direction. Thereby, the cutting blade 43 is positioned at the height position for starting the cutting process.

As described above, the cutting blade 43 is positioned at the position of the planned dividing line L to be cut, and after being positioned at the height position for starting the cutting process, the cutting process is started. At this time, the holding means 15 holding the workpiece W is additionally sent out in the -X direction at a predetermined cutting feed speed, whereby the holding means 15 and the cutting blade 43 are moved in the cutting feed direction (X axis direction) at a predetermined speed. ) Moves, and the cutting blade 43 cuts into the planned dividing line L where the workpiece W is detected while rotating at a high speed, and cuts the planned dividing line L.

Next, the cutting means 40 is fed stepwise in the Y-axis direction at intervals between adjacent planned dividing lines L, and the same cutting is performed to cut the planned dividing line L adjacent to the cut planned dividing line L. As shown above, by repeatedly performing stepped feeding and cutting, all the planned dividing lines L in the same direction are cut. Next, after the holding means 15 is rotated by 90 degrees by the rotating means 81, the same cutting is performed to cut all the planned dividing lines L horizontally and horizontally, and the workpiece W can be divided into individual wafers. Among them, the cutting processing uses the processing conditions described below. Cutter: Wheelstone diameter #2000~#3000 Cutting blade width (cutting width): 20~30μm Material to be processed: Silicon Cutting feed rate: 50~100mm/sec Spindle rotation number: 20000 rotations/min~30000 rotations/min

(Debris detection) During the cutting process of the workpiece W by operating the cutting device 1 as described above, the AE sensor 71 mounted on the tool holder 51 of the cutting means 40 senses the complex frequency components generated during cutting. The elastic wave is magnetically transmitted to the first coil means 73 and the second coil means 74 to form an electrical signal and is transmitted to the control means 75. In the control means 75, for example, the information shown in FIG. 4 is obtained. In FIG. 4, the horizontal axis is set to time (t), and the vertical axis is set to the value of the elastic wave signal sensed by the AE sensor 71 during the cutting process, that is, the AE value (V). The data of the time change of the AE value is the graph of the time axis waveform of the time characteristic data.

For the time characteristic data of the elastic wave signal, the analysis means 76 is used to perform Fourier transformation (for example, FFT) by setting the sampling time To to, for example, 1 millisecond. In this way, the frequency characteristic data, which is the frequency spectrum of the elastic wave signal decomposed for each frequency, is obtained. Figure 5 is the frequency axis waveform where the horizontal axis is set to frequency (f), the vertical axis is set to the size (intensity) of the elastic wave spectrum decomposed for each frequency, and the frequency characteristic data of the elastic wave signal is plotted. Chart.

The frequency band of the elastic wave generated by the contact between the cutting blade 43 and the workpiece W during cutting is known as a specific frequency band of 200 kHz to 600 kHz. Among them, the vibration of frequency less than 200kHz is caused by the sound of cutting water supplied by the cutting water supply means 46 or the sound of the driving part, and the vibration of frequency greater than 600kHz is caused by noise of the motor driver, etc. . Therefore, in the analysis means 76, as shown in FIG. 5, the frequency band from 200 kHz to 600 kHz of the elastic wave signal converted into the frequency axis waveform is specified, and the determination means 77 determines the Fourier transformed AE value in the frequency band from 200 kHz to 600 kHz. Whether it exceeds the preset first threshold value is used to determine whether debris occurs.

The first threshold value is determined by, for example, past processing experience. In terms of the method of determining the first threshold value, for example, cutting all the planned dividing lines L of the workpiece W in a state where the first threshold value has not been determined, and the entire time during the cutting process is expressed as AE The detector 71 senses elastic waves generated during cutting processing. The elastic wave signal sensed by the AE sensor 71 is transmitted to the control means 75 through the first coil means 73 and the second coil means 74.

On the other hand, the state of the cut formed in the workpiece W is imaged by, for example, a camera 90 of the alignment means 9 to perform cut inspection. As a result of the notch inspection, when debris is detected on the surface Wa of the workpiece W, the position of the planned dividing line L where the debris has occurred is investigated based on the captured image. At this time, in the cutting device 1, by comparing the image of the surface Wa of the workpiece W captured by the camera 90 with the cutting feed rate and the total length of the planned dividing line L, it is possible to specify the measurement from the start of cutting. Where and when the planned dividing line L is cut. Specify the location and time of chip generation during cutting. For example, take 1 millisecond including the chip generation time as the sampling time, and Fourier transform the time axis waveform of the elastic wave into the frequency axis by the analysis means 76 The waveform is the AE value of the elastic wave signal in the frequency band 200kHz to 600kHz included in the acquired frequency axis waveform, and the Fourier transformed AE value of the elastic wave signal generated by the cutter 43 when chipping is specified ( Peak value, etc.). Next, a value slightly lower than the AE value after the Fourier transform is set as the first threshold value.

When the elastic wave signal generated on the cutting blade 43 due to cutting exceeds the first threshold set as described above, the judging means 77 determines that chipping occurs in the cut of the workpiece W by the cutting blade 43 and the cutting process There is an exception. In Figure 5, the frequency axis waveform of the elastic wave at a certain time during cutting is drawn. At the position P1 near 400kHz in the graph, the AE value after Fourier transform exceeds the first threshold S1. Accept this and judge The means 77 judges that chipping occurs in the workpiece W system and there is an abnormality in the cutting process.

If it is determined by the judgment means 77 that debris has occurred in the workpiece W, the notification means 78 informs the operator or the like of the occurrence of debris, and prompts maintenance work and the like.

Among them, the frequency band of the elastic wave generated by the cutter 43, that is, the 200kHz to 600kHz band, is divided into four of 200kHz to 300kHz, 300kHz to 400kHz, 400kHz to 500kHz, and 500kHz to 600kHz. Using the above method, set the The first threshold value, and analysis of each elastic wave signal, which can perform more accurate debris detection. At this time, the first threshold value can also be set to different values for the four frequency bands that have been differentiated.

As described above, the Fourier transform is performed using the analysis means 76 included in the cutting device 1, whereby among the generated elastic wave signals, the elastic wave signals generated by the cutting blade 43 are specified, and the elastic wave signals are compared by comparing the elastic wave signals. The Fourier-transformed AE value of the wave signal and the set first threshold value can determine whether debris occurs with better accuracy.

(Debris detection using statistical feature quantities) In the detection of debris by the elastic wave signal, the average value of the Fourier transformed AE value is obtained for each frequency band, and the feature value is obtained from the complex average value within a predetermined time, and the feature value is used to determine whether The formation of debris is appropriate.

The above-mentioned characteristic quantity system is defined as follows, for example. During the cutting of the workpiece W, the AE sensor 71 senses all the elastic waves from the start to the end of the cutting, and forms the elastic wave signal to be transmitted to the control means 75. In this elastic wave signal, the time characteristic data of the first planned dividing line L cut by the cutter 43 during the cutting process is set to a sampling time of 1 millisecond, and Fourier transform is performed for each time division. In FIG. 6, as an example, the frequency axis waveform in the frequency band of 200 kHz to 300 kHz among the frequency bands of elastic waves generated by the cutter is drawn. After that, the frequency average value of the Fourier-transformed AE values in each frequency band (200 kHz to 300 kHz in the example of FIG. 6) in each time zone divided every 1 millisecond is calculated for one line. If the frequency average value of the complex Fourier transformed AE value of 1 line obtained as shown above is plotted on the spectrum size with the horizontal axis as time (t) and the vertical axis as the Fourier transformed AE value On the graph of (intensity), the time-axis waveform of the frequency average of the AE value after Fourier transform as shown in FIG. 7 is drawn. The inclination of the left and right parts of the graph in FIG. 7 shows how the AE value changes after the Fourier transform is large when the tape is cut by the cutter 43. The flat part in the graph shows the Fourier when the workpiece W is being cut. The converted AE value. The length in the horizontal axis direction in the center part of the graph of FIG. 7, that is, the time for the planned dividing line L of the workpiece W to perform one-line cutting is the predetermined time T1, and the Fourier transform in the predetermined time T1 The difference between the maximum value of the frequency average value of the AE value and the median value is set as the feature quantity.

Every time the planned dividing line L of one line is cut, the analysis means 76 calculates the feature quantity set as described above, and this operation is performed on the entire line. When the calculated feature amount exceeds the second threshold value, the judgment means 77 judges that chipping occurs in the cut of the workpiece W by the cutting blade 43 and there is an abnormality in the cutting process.

However, the second threshold value is the same as the first threshold value, based on the chip position found in the image of the planned dividing line L obtained by the camera 90, and the chip position or cutting feed speed or The scrap time derived from the total length of the planned dividing line L, etc. is set. For example, while cutting all the planned dividing lines L, the AE sensor 71 senses the elastic wave generated by the cutting blade 43 during the cutting process, and transmits it to the control means 75 as an elastic wave signal. On the other hand, similarly to the setting of the first threshold value, the state of the cut after cutting is investigated by the camera 90 of the alignment means 9 and the like. When debris is found during the incision inspection, the location and time of detection of the debris are derived based on the image captured. Next, Fourier transform is performed on the elastic wave signal of one line including the debris position with the sampling time set to 1 millisecond, and the frequency average of the Fourier transformed AE values in the frequency band of 200 kHz to 300 kHz is calculated. After calculating the frequency average value of the elastic wave signal of the planned dividing line L including the chip position for 1 line, calculate the difference between the maximum value and the median value of the frequency average value within the predetermined time T1, and set it as the second threshold value.

When the characteristic quantity calculated from the elastic wave signal sensed by the AE sensor 71 and transmitted to the control means 75 during cutting exceeds the second threshold value S2 set as described above, the determination means 77 determines Chips are generated in the cut of the workpiece W by the knife 43 and there is an abnormality in the cutting process. In FIG. 8, the line number (n) indicating the position of the line on the horizontal axis and the feature amount on the vertical axis are drawn in FIG. In P2 of the graph of FIG. 8, the feature amount exceeds the second threshold S2, and the judgment means 77 judges that debris has occurred after receiving this.

In the background of setting the feature quantity according to the difference between the maximum value of the frequency average value of the Fourier transformed AE value and the median value within the predetermined time T1, there is the difference between the maximum value and the median value of the frequency average value of the elastic wave signal The greater the difference, the greater the frequency characteristic data unevenness of each sampling segment when the one-line elastic wave signal is Fourier transformed, and the greater the frequency characteristic data unevenness, the more abnormal the cutter 43, etc. On the other hand, in the workpiece W, the possibility of chipping is greater. When the difference between the maximum value of the frequency average value of the Fourier-transformed AE value and the median value included in the elastic wave signal of 1 line within the predetermined time exceeds the second threshold value, the cutter 43 The elastic wave signal data of the elastic wave generated in the cutting of one line has large unevenness, and it is judged that chipping has occurred.

In addition, the feature value can also be defined as if there are N pieces of data of the frequency average value of 1 line in the predetermined time T1 shown in FIG. 7, the value is greater than {3(N+1)/4}, The value after subtracting the largest value of {(N+1)/4} is the so-called Interquartile Range.

If the feature quantity is defined as the interquartile range as described above, the second threshold value is also set as the interquartile range. When setting the second threshold value when the feature quantity is defined as the interquartile range, first, the time characteristic data of the elastic wave signal when all the planned dividing lines L are cut is transmitted to the control means 75. On the other hand, based on the image of the surface Wa of the workpiece W captured by the camera 90 shown in FIG. 1 during the cutting process, the location of the chip generated by the cutting process is specified, and the time when the chip occurs is also derived . Next, set the time characteristic data of the elastic wave signal of 1 line where debris occurred in the planned dividing line L, set the sampling time to 1 millisecond, and perform Fourier transformation by the analysis means 76 to obtain the frequency characteristic data of the elastic wave signal , And calculate the frequency average of the Fourier-transformed AE values in each frequency band of one line, for example, the frequency band of 200 kHz to 300 kHz. After that, among the data of the frequency average value of 1 line of the occurrence of debris, among the N included in the predetermined time T1, specify the {3(N+1)/4}th largest value and For the largest value {(N+1)/4}, the subtracted value (interquartile range) is set as the second threshold. When the feature quantity during cutting exceeds the set second threshold value, the judgment means 77 judges that chipping occurs in the cut of the workpiece W cut by the cutting blade 43 and there is an abnormality in the cutting process.

In the case where the feature quantity is set to the interquartile range, as described above, as in the case where the feature quantity is set to the value after subtracting the maximum value and the median value of the frequency average value, the difference of the data is compared. The average size to determine whether debris occurs. That is, the larger the quartile range of the frequency average value included in the predetermined time calculated from the elastic wave signal of the elastic wave generated during cutting, the Fourier transform of the elastic wave signal of 1 line The greater the unevenness of the frequency characteristic data of each sampling division, if the quartile range exceeds the second threshold, it is judged that debris occurs in the workpiece W.

In addition, it is also possible to set the third threshold value. Once the number of times the feature quantity exceeds the third threshold value exceeds the preset number of times, it is determined that chipping occurs in the incision of the workpiece W by the cutting tool 43 and the cutting The processing has an abnormal composition. However, the third threshold value may be the same value as the second threshold value, or may be a different value.

For example, if the above-mentioned set number of times is set to 3 times, and the feature quantity exceeds the third threshold value for the third time, it is determined that chipping occurs in the workpiece W system. In the graph of FIG. 8, the third threshold S3 is exceeded for the third time near P3. At this time, it is determined by the determination means 77 that debris has occurred. If it is determined by the judging means 77 that debris has occurred, the notification means 78 is used to notify the operator or the like of the summary.

By using the feature amount set as described above, it is possible to more accurately determine whether chipping occurs.

1: Cutting device 10: Pedestal 11: cover 12: Snake belly cover 13: Door type column 15: Keep the means 150: Attraction Department 150a: keep face 151: Frame 17: Fixture 18: Cutting feed means 180: Ball screw 181: Rail 182: Motor 183: movable plate 184: Rotation axis 20: Box storage area 21: Box lifting means 22: Stage 24: Washing means 25: Rotator platform 26: Washing water nozzle 30: Grading feed method 32: movable plate 31: Rail 33: Ball screw 330: Rotation axis 34: Motor 35: Cutting feed means 36: Rail 37: Supporting member 38: Ball screw 380: Rotation axis 39: Motor 40: Cutting means 41: Mandrel shell 41a: The front face of the spindle housing 42: Mandrel 43: Cutter 44: screw hole 45: knife cover 46: Cutting water supply means 47: cover member 48: bracket 49: opening 51: Tool holder seat 52: Fitting hole 53: Bushing 54: round recess 55: Through hole 56: Flange 56a: Surface of flange 56 56b: Back of flange 56 57: Male Spiral 58: Washer 59: fixing bolt 61: Hub abutment 62: Cutter 63: Insert hole 65: fixed nut 71: AE sensor 73: The first coil means 74: The second coil means 75: Control 76: Analysis 77: Judgment 78: Report 80: Attraction 81: Rotating means 82: Rotation axis 83: shell 9: Alignment means 90: Camera D: Components L: Split planned line W: to be processed Wa: The surface of the workpiece Wb: The back of the processed object T: Attach tape F: Frame S1: The first threshold S2: second threshold S3: The third threshold P1: The point exceeding the first threshold P2: The point exceeding the second threshold P3: The point where the third threshold is exceeded for the third time To: sampling time T1: scheduled time

[Fig. 1] A perspective view showing the entire cutting device. [Fig. 2 is a perspective view showing the elements constituting the cutting means. [Fig. 3] A cross-sectional view showing the cutting means. [Figure 4] is a graph showing the time-axis waveform of the elastic wave signal. [Figure 5] is a graph showing the frequency axis waveform of the elastic wave signal. Fig. 6 is a graph showing the AE value after Fourier transform in the frequency band of 200 kHz to 300 kHz among the frequency axis waveforms of the elastic wave signal. Fig. 7 is a graph showing the change in the frequency average value of the AE value after the Fourier conversion of the frequency band from 200 kHz to 300 kHz among the frequency characteristic data obtained by the Fourier conversion of the elastic wave signal. [Fig. 8] A graph of the characteristic quantity (the value obtained by subtracting the median value from the maximum value of the frequency average value of the Fourier transformed AE value within a predetermined period of time, or the interquartile range of the frequency average value) , Used to judge whether the characteristic quantity exceeds the 2nd threshold and the 3rd threshold.

1: Cutting device

9: Alignment means

10: Pedestal

11: cover

12: Snake belly cover

13: Door type column

15: Keep the means

17: Fixture

18: Cutting feed means

20: Box storage area

21: Box lifting means

22: Stage

24: Washing means

25: Rotator platform

26: Washing water nozzle

30: Grading feed method

31: Rail

32: movable plate

33: Ball screw

34: Motor

35: Cutting feed means

36: Rail

37: Supporting member

38: Ball screw

39: Motor

40: Cutting means

41: Mandrel shell

42: Mandrel

43: Cutter

45: knife cover

46: Cutting water supply means

75: Control

80: Attraction

81: Rotating means

82: Rotation axis

83: shell

90: Camera

150: Attraction Department

150a: keep face

151: Frame

180: Ball screw

181: Rail

182: Motor

183: movable plate

184: Rotation axis

330: Rotation axis

380: Rotation axis

D: Components

F: Frame

L: Split planned line

T: Attach tape

W: to be processed

Wa: The surface of the workpiece

Wb: The back of the processed object

Claims (3)

A cutting device comprising: a holding means for holding a workpiece; a cutting means provided with a cutting blade for cutting the workpiece held by the holding means; and a cutting water supply means for supplying cutting water to the cutting blade; A cutting feed means that moves the cutting tool and the holding means in the cutting feed direction; it is arranged on the cutting means or the holding means and senses the elastic wave generated by the cutting tool by cutting AE sensor; and cutting device of control means, The control method is: The AE sensor is used to sense the elastic wave containing complex frequency components generated when the cutting tool cuts the workpiece, and the elastic wave signal sensed by the AE sensor is Fourier transformed. The frequency band of the elastic wave signal generated by the cutter, In the specific frequency band, if the value of the elastic wave signal after Fourier transform exceeds the preset first threshold value, it is determined that debris is generated in the incision of the workpiece by the cutting tool and there is abnormal. Such as the cutting device of claim 1, wherein the control means is: The average value of the value obtained by Fourier transform of the elastic wave signal is obtained for each frequency band, and the characteristic value is obtained from the average value of the complex number within a predetermined time, Once the feature quantity exceeds the preset second threshold value, it is determined that chipping occurs in the incision of the workpiece by the cutting tool and there is an abnormality in the cutting process. For example, the cutting device of claim 2, wherein the control means is: the number of times the characteristic quantity exceeds the preset third threshold value once exceeds the preset number of times, it is judged that the cutting of the workpiece by the cutting tool occurs Chips and abnormalities in cutting.

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