JP3748148B2 - Laser processing defect detection method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser processing failure state detection method and apparatus.
[0002]
[Prior art]
The machining status in laser machining changes depending on the material and thickness of the workpiece, and changes probabilistically even if the material and thickness are the same or depending on the machining shape, so the operator always monitors the machining status. If a machining defect occurs, stop the machine immediately, determine the type or condition of the machining defect and change the machining conditions according to the situation, or generate some machining defect. Predictive measures are taken, such as setting a larger number of processed products.
[0003]
[Problems to be solved by the invention]
The above-described change in the machining state is not only probabilistic as described above, but may also occur due to a change in factors such as deterioration of equipment used for machining. For example, processing defects may continue thereafter due to changes in factors such as the progress of dirt on the condenser lens. In such a case, not only processing failures occur continuously in the product but also cause the processing machine itself to break down, so appropriate measures are necessary, and monitoring of the processing state by the operator should be stopped. I can't.
[0004]
In addition, when a processing failure occurs due to a change in the processing state, it is based on the operator's determination whether it is caused by a change in material, plate thickness, etc., or due to a change in the processing shape, etc. It is an obstacle to automation or unmanned laser processing.
[0005]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a laser processing failure state detection method and apparatus using a machine.
[0006]
[Means for Solving the Problems]
As a means for solving the above-mentioned problem, the laser processing failure state detection method according to claim 1 , wherein the slit part or the round hole of the laser cutting part of the workpiece is imaged, and the image data of the cutting part is image processing apparatus In the laser processing failure state detection method for detecting the processing failure state of the workpiece by processing in the above, the slit width of the slit portion or the radius of the round hole is measured a plurality of times by changing the imaging position by the imaging device, and the cut surface Similarly, the unevenness of the upper part is measured a plurality of times by changing the imaging position, and when the variation of each measured value processed by the image processing device is larger than the variation of the reference value, it is determined that the processing failure in the burning state is caused, When the variation is less than the reference value, the average value of a plurality of measurements is calculated, and the average value is compared with the set value, and when the average value is greater than the set value, It determines that the factory defect, the when the average value is less than the set value is to the subject matter to be determined as a good cut.
[0007]
Therefore, the processing state changes irregularly depending on the material and thickness of the workpiece, and changes unpredictably depending on the processing material, etc. even if the material and thickness are the same. Therefore, the operator is freed from the monitoring work of the machining state and can perform other work. Further, since the determination of the processing failure state is made quantitatively by the machine without relying on human beings as in the prior art, there is no variation in the determination and an accurate determination is possible.
[0008]
The laser processing failure state detection device according to claim 2 performs image processing on an image pickup device that picks up an image of a slit portion or a round hole of a laser cutting processing portion of a workpiece, and image data of the cutting processing portion picked up by the image pickup device. Using the imaging device, the slit width of the slit part or the radius of the round hole is measured a plurality of times by changing the imaging position, and the unevenness at the top of the cut surface is the same. When the variation of each measured value processed by the image processing device is larger than the variation of the reference value, it is determined that the burning state is defective, and the variation is the reference value. When it is less than the average value of a plurality of measurements is obtained by calculation, the average value is compared with the set value, and when the average value is greater than the set value, it is determined that the processing failure in the gouging state, When serial average value is less than the set value is to the subject matter to be determined as a good cut.
[0009]
The machining state varies irregularly depending on the material and plate thickness of the workpiece, and changes unpredictably depending on the machining shape and the same material and plate thickness, but the machine is monitored by the machine because the machining state is monitored. Is freed from the monitoring work of the machining state and can perform other work. Further, since the determination of the processing failure state is made quantitatively by the machine without relying on human beings as in the prior art, there is no variation in the determination and an accurate determination is possible.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram for explaining the relationship between a part of a laser processing head of a laser processing machine using a laser processing defect state detection apparatus according to the present invention and a workpiece. Referring to FIG. 1, a laser beam machine 1 is provided with a machining table (not shown) that is movable in the X-axis direction (direction orthogonal to the paper surface in FIG. 1), and a workpiece clamp 3 is placed on this machining table. The workpiece W to be machined clamped at is placed. Further, an upper frame 5 of a gate shape is provided above the processing table across the processing table.
[0025]
A plurality of parallel guide rails 7 extending in the Y-axis direction (left-right direction in FIG. 1) are laid on the front surface of the upper frame 5. A ball screw 9 extending in the Y-axis direction is provided between the guide rails 7. A drive motor My is connected to one end of the ball screw 9, for example, at the right end in FIG. At the same time, the other end of the ball screw 9, for example, the left end in FIG.
[0026]
A Y-axis carriage 15 is provided via a nut member (not shown) screwed to the ball screw 9, and a plurality of guide members (not shown) are provided on the Y-axis carriage 15, and each guide member serves as the guide rail. 7 is guided along. The Y-axis carriage 15 is provided with a laser processing head 17 and a nozzle 19 is provided below the laser processing head 17.
[0027]
With the above configuration, when the drive motor My is driven, the ball screw 9 rotates and the Y-axis carriage 15 is moved in the Y-axis direction. The Y-axis carriage 15 is guided by the guide rail 7 through the guide member and moves. Accordingly, the workpiece W clamped by the workpiece clamp 3 moves in the X-axis direction and the laser machining head 17 moves in the Y-axis direction, and the laser machining head 17 is positioned at a desired position of the workpiece W. A laser beam is irradiated from the nozzle 19 provided at the lower part of the workpiece, and the workpiece W is subjected to laser processing such as a round hole.
[0028]
In the Y-axis carriage 15, for example, an imaging device unit 21 is provided in the vicinity of the right side of the laser processing head 17. In this imaging device unit 21, an imaging device unit case 23 is provided in the Y-axis carriage 15, and a CCD camera 25 as an image capturing camera is provided in the imaging device unit case 23. Are provided with a lens unit 27 and a UV filter 29 in this order downward. The CCD camera 25 is a camera that captures, for example, a round hole or groove width, the lens unit 27 adjusts the aperture and focus, and the UV filter 29 protects the lens unit 27 and the CCD camera 25 from ultraviolet rays. is there.
[0029]
An air cylinder 31 is provided in the imaging device unit case 23, and a piston rod 33 is attached to the lower portion of the air cylinder 31. A support member 37 having a ring illumination 35 is attached to the lower end of the piston rod 33. A work presser 41 is provided at the lower end of the support member 37 via a spring 39. A relay terminal block 43 is provided in the imaging device unit case 23, which is a limit switch for the air cylinder 31 and a relay terminal block for the ring illumination 35. A purge solenoid 45 and an air cylinder solenoid 47 are provided on the upper right side of the upper frame 5.
[0030]
An image processing device 49 for processing an image of the imaging device 21 is shown in FIGS. 2 (A), (B), (C), and (D). 2, the image processing device 49 includes a power switch 51, a power display LED 53, a CCD camera connection cable 55, an NC connection cable 57, a power cable 59, and a fan 61. FIG. 3 shows a system configuration diagram of the electrical system of the imaging device unit 21. In FIG. 3, the image processing device 49 and the NC high voltage board 63 are connected by a cable 65. The relay terminal block 43 and the NC high power panel 63 are connected by a relay cable 67. The purge solenoid 45, the air cylinder solenoid 47 and the NC high power panel 63 are connected by solenoid cables 69 and 71, respectively. The NC device 73 and the image processing device 49 are connected by the NC connection cable 57.
[0031]
The relay terminal block 43 and the ring illumination 35 are connected by an illumination cable 75, and the upper and lower limit switches 77 and 79 of the air cylinder 39 and the relay terminal block 43 are connected by switch cables 81 and 83. is there. The monitor television 85 and the image processing device 49 are connected by a monitor cable 87.
[0032]
FIG. 4 shows a system configuration diagram of an air system of the imaging device unit 21. In FIG. 4, the upper and lower cylinder chambers of the air cylinder 31 are shown. For example, one ends of the pipes 89 and 91 are connected, and the other ends of the pipes 89 and 91 are connected to the back side of the air cylinder solenoid 47. One end of a pipe 93 is connected to the front side of the solenoid 47 for the air cylinder, and the other end of the pipe 93 is connected to a union tee 97 of an air three-point set 95. Furthermore, one end of a pipe 99 is connected to the front side of the purge solenoid 45, and the other end of the pipe 99 is connected to a branch elbow 101 of an air three-point set 95. One end of a pipe 103 is connected to the back side of the purge solenoid 45, and the other end of the pipe 103 is connected to an air purge ring-shaped hole 105 formed in the work holder 41.
[0033]
By operating the NC device 73 shown in FIGS. 3 and 9 and controlling the image processing device 49 via the NC high voltage board 63, the surface of the processed part of the processed workpiece is imaged by the CCD camera 25 with the above configuration. The Further, the ring illumination 35 is turned on via the NC high power panel 63 and the relay terminal block 43, the surface of the work is illuminated, and the upper and lower limit switches 77 and 79 of the air cylinder 39 are turned on and off. Further, the purge solenoid 45 and the air cylinder solenoid 47 are turned on and off via the NC high voltage board 63.
[0034]
In FIG. 4, when compressed air is supplied to the upper cylinder chamber of the air cylinder 31 through the air cylinder solenoid 47 and the pipe 89 via the pipe 93 via the union tee 97 of the air three-point set 95, the piston rod 33 is moved. Since the workpiece is lowered, the workpiece presser 41 is also lowered and the workpiece W is pressed by the workpiece presser 41 from above. In addition, when compressed air is supplied to the lower cylinder chamber of the air cylinder 31 via the pipe 93 through the air cylinder solenoid 47 and the pipe 91 via the union tee 97 of the air three-point set 95, the piston rod 33 rises. The work clamp 41 is also raised.
[0035]
Further, if a dust collector (not shown) is operated with the workpiece presser 41 holding the workpiece W from above, dust or the like on the workpiece W is sucked from the hole 103 formed with the workpiece presser 41 and the piping 101, The dust is collected by the dust collector through the purge solenoid 45, the pipe 97, and the air three-point set 95, and the work W is cleaned cleanly.
[0036]
FIG. 5 and FIG. 6 are flowcharts of the laser processing defect state detection method according to the present invention. Hereinafter, based on this flowchart, the measurement of the linear cutting part or round hole formed in the workpiece | work W and the processing defect state detection method are demonstrated. First, as preparation, the slit width at the time of good cutting is set in step S1. When a machining state monitoring star and a command are issued, a machining monitoring program is executed (step S2). In step S3, the monitoring position on the workpiece is moved and positioned to a position directly below the CCD camera 25.
[0037]
In the next step S4, the work W is pressed and fixed by the work presser 41 and the ring illumination 35 is turned on. In step S5, the CCD camera 25 images the processing position of the workpiece W, the image processing device 49 performs image processing on the captured image data, and outputs the processed image data to the NC device 73.
[0038]
In step S6, the work presser 41 is raised and the ring illumination 35 is turned off. In step S7, it is determined whether the monitoring of the machining state is slit monitoring. If it is slit monitoring, go to step S8, otherwise go to step S9. When the process has come to step S8, since it is the case of slit monitoring, it is determined whether or not a slit has been detected in step S8. If no slit is detected, it indicates that the workpiece W has not been cut, so that it is recognized as a defective processing (3) in the ruled state in step S19.
[0039]
If the slit is detected in the condition determination of step S8, the slit width is measured a plurality of times at different positions in step S10. In the condition determining step S9, it is determined whether or not a round hole has been detected. If a round hole is detected, the radius of the round hole is again measured several times at different positions in step S10. carry out. If the round hole cannot be detected in step S9, the work W has not been cut. Therefore, in step S19, it is recognized as a processing defect (3) in the ruled state. The number of measurements is preferably at least 3 times.
[0040]
Next, in step S11, the amount of unevenness at the top of the cut surface is measured, and the variation in the measured value is calculated in the next step S12. The concave / convex amount at the top of the cut surface is obtained by calculating the position coordinate in the Z-axis direction (not shown) in the direction orthogonal to the XY-axis where the focal position of the CCD camera 25 is aligned with the surface of the convex portion. It can be detected as a difference from the distance from the surface of the workpiece W.
[0041]
Next, in step S13, the magnitude of the variation in the measured value is determined. Note that the magnitude of the variation is determined based on a variation reference value set based on a preset cutting accuracy. If the variation in the measured value is larger than the reference value in step S13, it is recognized as a burning defective (1) in step S14. If the variation in the measured values is less than the reference value in step S14, the average value of the measured values is calculated (step S15).
[0042]
Next, the average value obtained in step S15 is compared with the set value, and when the average value is larger than the set value, it is recognized as a processing defect (2) in the gouging state (step S17). If the average value obtained in step S15 is less than the set value, it is recognized as good cutting (step S18). The set value in step S16 is the slit width at the time of good cutting at the time of slit detection, and means an instruction value specified in the program at the time of round hole detection and unevenness detection.
[0043]
In step S14, step S17, and step S19, if it is recognized that the machining defect in the burning state, the machining defect in the gouging state, and the machining defect in the crease state are all determined in step S20, whether or not the number of machining defects is greater than an allowable value. If the number of processing failures is equal to or greater than an allowable value, a processing failure alarm is displayed on the monitor TV 85 and the display of the NC unit 73 and laser processing is interrupted.
[0044]
When the number of machining defects is less than the allowable value in step S20, it is determined in next step S21 whether or not there is a next machining. If there is a next machining, the three types of machining are performed in step S22. The next processing is performed after changing the laser cutting processing conditions so that the processing conditions are improved corresponding to the defect (step S23). When the next machining is performed, the process returns to the machining monitoring main step S3 and the machining monitoring program is continued. If there is no next machining in step S21, the machining monitoring program is terminated.
[0045]
If it is determined in step S18 that the cutting is good, the next machining is performed (step S21), the process monitoring main process S3 is resumed, and the machining monitoring program is continued.
[0046]
The command lines constituting the program in the laser processing failure state detection method using the imaging device 21 and the image processing device 49 are described as follows. "G141A5I J E Q K ;] The meaning of the command line argument is as follows. G141A5: Process monitoring state mode, I: Monitoring position X coordinate, J: Monitoring position Y coordinate, E: Uneven state reference value above the cutting position, Q: Monitoring shape designation, Q1 slit monitoring, round hole when omitted Monitoring, R: Radius of hole (mm), K: Allowable number of machining failures.
[0047]
Next, an example of the machining state monitoring program is as follows. G141A5K3; (setting of allowable number of machining defects), G141A5IΔΔJΔΔE1Q1; (slit machining state monitoring), G141A5IΔΔJΔΔE2R2; (4 mm diameter hole machining state monitoring). ΔΔ represents an appropriate numerical value.
[0048]
Next, in the processing failure state detection method of the present invention, the shape that can be monitored, the position that can be monitored, and the position that cannot be monitored will be described with reference to FIGS. In the processing failure state detection method of the present invention, round holes, straight cut portions and slits are monitored, and holes other than round holes are not monitored.
[0049]
Now, referring to FIG. 7, as an example of laser cutting processing, a polygonal product P having three round holes 111, one square hole 113 and two V-shaped slits 115 is taken as a workpiece W ( Or an example of cutting from a base material) is shown. In this polygonal product P, those that can be monitored are the round hole 111 at the monitoring position A and the outside position as shown in FIG. And the slit 115 at the monitoring position C. On the other hand, the square hole 113 at the monitoring position D, the corner of the straight cut part where the product side falls like the monitoring position E, and the corner not connected to the both ends of the visual field to be monitored like the monitoring position F are monitored. Not applicable.
[0050]
The configuration of the laser processing failure state detection device 121 is shown in FIG. The laser processing failure state detection device 121 includes a CCD camera 25 as the image capturing camera, an image processing device 49 that processes an image captured by the CCD camera 25, and laser processing failure state information processed by the image processing device 49. Based on the machining conditions of the workpiece W and the NC device 73 for controlling the movement and positioning of the workpiece W, etc. The CCD camera 25 may be fixed and the workpiece W may be moved in the XY direction with respect to the CCD camera 25.
[0051]
The image processing device 49 includes an image memory 121, a CPU 123, a ROM 125, a RAM 127, and an I / O (input / output device) 129. The image memory 121 stores a digital signal from the CCD camera 25 input via the cable 55. The ROM 125 stores a laser processing failure state detection program, a reference value, and the like according to the algorithm described with reference to FIGS. A RAM 127 is a temporary memory used when executing the program.
[0052]
The I / O (input / output device) 129 is connected to the data bus 131 of the image processing device 49 and the input / output device (not shown) inside the NC device 73, and an activation signal from the NC device 73 and NC It serves to transmit a data signal to the device 73. The I / O 129 is connected to a relay (not shown) of the ring illumination 35, and turning on or off of the ring illumination 35 is controlled by the CPU 123 of the image processing device 49. The NC device 73 controls the movement and positioning of the processing table, the laser processing head 17 and the CCD camera 25 of the laser processing machine 1 and also controls the air cylinder solenoid 47 to move the workpiece presser 41 up and down. Also has control.
[0053]
In the above configuration, if the laser processing failure state detection program according to the algorithm of FIGS. 5 and 6 is operated, the image processing device 49 performs an arithmetic process on the CPU 123 on the image captured by the CCD camera 25 at the processing position, Judge whether the processing state is good cutting or processing failure, and if there is a next processing in the case of good cutting, determine whether the processing is a good cutting kana for the next processing as well To implement.
[0054]
If a machining defect is detected, it is determined whether the machining defect is in a burning state, a gouging state, or not cut at all, and the machining conditions are changed to improve the machining defect. A command is output to the NC device 73 via the I / O 129. Then, the next processing is performed under the changed processing conditions. If the allowable number of machining defects is specified by the program, the laser processing defect state detection program is executed until the allowable number of machining defects is exceeded.
[0055]
Further, the CPU 123 outputs a command to turn on the ring illumination 35 to the NC device 73 via the I / O 129 during imaging of the processing part of the workpiece W to turn on the ring illumination 35 and drive the air cylinder solenoid 47. The work presser 41 is operated by outputting a command to be operated. The NC device 73 drives a drive motor Mx of a workpiece positioning device (not shown) to position the workpiece W at an arbitrary position in the X-axis direction, and also drives a drive motor My of the Y-axis carriage 15 to charge the CCD. The camera 25 can be positioned at an arbitrary position in the Y-axis direction. Therefore, the processing part of the workpiece W can be positioned directly below the CCD camera 25 by appropriately driving the drive motors My and Mx.
[0056]
【The invention's effect】
As can be understood from the description of the embodiment as described above, according to the invention described in claim 1, since the machine is constantly monitoring the machining state, the operator is released from the machining state monitoring work and other work is performed. Can be performed. Further, since the determination of the processing failure state is made quantitatively by the machine without relying on human beings as in the prior art, there is no variation in the determination and an accurate determination is possible.
[0057]
According to the invention described in claim 2, as in the invention of claim 1, since the machine is constantly monitoring the machining state, the operator can be released from the monitoring work of the machining state and perform other work. Become. Further, since the determination of the processing failure state is made quantitatively by the machine without relying on human beings as in the prior art, there is no variation in the determination and an accurate determination is possible.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a relationship between a laser processing head portion of a laser processing machine using a laser processing failure state detection apparatus according to the present invention and a workpiece.
FIGS. 2A and 2B are external views of an image processing apparatus of a laser processing defect state detection apparatus, where FIG. 2A is a plan view of the image processing apparatus, FIG. 2B is a front view, and FIG. 2C is a right side view; (D) is a left side view.
FIG. 3 is a system configuration diagram of an electrical system of an imaging device unit of a laser processing defect state detection device.
FIG. 4 is a system configuration diagram of an air system of an imaging device unit of a laser processing defect state detection device.
FIG. 5 is a flowchart of a laser processing failure state detection method according to the present invention.
FIG. 6 is a flowchart of a laser processing failure state detection method according to the present invention. FIG. 7 is an explanatory diagram of a monitorable shape, a monitorable position, and an impossible position in the laser processing failure state detection method according to the present invention. .
8 is an explanatory diagram enlarging the monitorable shape, the monitorable position, and the impossible position in FIG. 7;
FIG. 9 is a diagram for explaining an embodiment of a laser processing failure state detection apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Laser processing machine 3 Work clamp 5 Upper frame 7 Guide rail 9 Ball screw 13 Bearing 15 Y-axis carriage 17 Laser processing head 19 Nozzle 21 Imaging device unit 23 Imaging device unit case 25 CCD camera 27 Lens unit 29 UV filter 31 Air cylinder 33 Piston rod 35 Ring illumination 37 Support member 39 Spring 41 Work clamp 43 Relay terminal block 45, 47 Solenoid 49 Image processing device 51 Power switch 53 Power display LED
55, 57, 59, 65, 69, 71, 75, 81, 83, 87 Cable 61 Fan 63 NC high power panel 67 Relay cable 73 NC device 77, 79 Limit switch 85 Monitor television 89, 91, 93, 99, 103 Piping 95 Air 3-point set 97 Union tee 101 Elbow 105 Hole 121 Image memory 123 CPU
125 ROM
127 RAM
129 I / O (input / output device)
131 Data bus Mx drive motor My drive motor W Workpiece

Claims (2)

Imaging the slit or round hole of the laser cutting processing part of the work, and processing the image data of the cutting processing part with an image processing apparatus to detect a processing failure state of the work, and the laser processing failure state detection method, The slit width of the slit part or the radius of the round hole is measured a plurality of times by changing the imaging position by the imaging device, and the unevenness at the upper part of the cut surface is similarly measured a plurality of times by changing the imaging position and processed by the image processing device. When the variation of each measured value is larger than the variation of the reference value, it is determined that the machining state is in a burning state, and when the variation is less than the reference value, an average value of a plurality of measurements is calculated and obtained. The average value is compared with the set value, and when the average value is larger than the set value, it is determined that the gouging state is defective, and when the average value is less than the set value, it is determined as good cutting. Laser processing defect state detecting method according to. A laser processing failure state detection device comprising: an imaging device that captures an image of a slit portion or a round hole of a laser cutting processing portion of a workpiece; and an image processing device that performs image processing on image data of the cutting processing portion captured by the imaging device. The image processing unit measures the slit width of the slit portion or the radius of the round hole a plurality of times while changing the imaging position, and similarly measures the unevenness on the upper surface of the cut surface a plurality of times while changing the imaging position. When the variation of each measured value processed by the device is larger than the variation of the reference value, it is judged as a processing failure in the burning state, and when the variation is less than the reference value, the average value of multiple measurements is calculated. The average value is compared with the set value, and when the average value is greater than the set value, it is determined that the processing is defective in the gouging state, and when the average value is less than the set value, it is determined as good cutting. Laser processing defect state detecting apparatus according to claim Rukoto.

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