Laser machining machine and machining failure detection method

Abstract

To prevent erroneous detection of machining failure by accurately determining the presence or absence of any machining failure during laser beam cutting.SOLUTION: A laser machining machine 1 comprises: a camera 5 that captures light emitted from a machining point of sheet metal W when the sheet metal W is irradiated with a laser beam and cut; and a control unit 7 that detects a machining failure of the sheet metal W on the basis of the emitted light captured by the camera 5. The control unit 7 measures a degree of spread of the emitted light in a direction perpendicular to a traveling direction of the laser beam, and determines the presence or absence of any machining failure in the sheet metal W on the basis of the measured degree of spread of the emitted light.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a laser processing machine and a processing defect detection method. [Background technology]

[0002] Patent Document 1 describes a laser processing machine that determines whether or not a burning defect has occurred. The laser processing machine in Patent Document 1 detects reflected light when a laser beam is irradiated onto a metal sheet to cut it, and determines whether or not a burning defect has occurred by calculating a standard deviation from the detection level of the reflected light at a predetermined calculation cycle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-45779 Summary of the Invention [Problem to be solved by the invention]

[0004] However, since the detection level of reflected light changes due to factors other than processing defects, the conventional laser processing machines described above have the problem that they may erroneously detect a processing defect when there is no processing defect. [Means for solving the problem]

[0005] A laser processing machine according to one embodiment of the present invention includes a camera that captures the radiation light emitted from a processing point of a sheet metal when a laser beam is irradiated onto the sheet metal to cut it, and a control unit that detects processing defects of the sheet metal based on the radiation light captured by the camera, wherein the control unit measures the degree to which the radiation light spreads in a direction perpendicular to the direction of travel of the laser beam and determines whether or not the sheet metal has been processed defectively based on the measured degree of spread of the radiation light.

[0006] A method for detecting processing defects according to another aspect of the present invention involves using a camera to capture an image of radiated light emitted from a processing point on a metal sheet when a laser processing machine irradiates a laser beam onto the metal sheet to cut it, measuring the extent to which the captured radiated light spreads in a direction perpendicular to the direction of travel of the laser beam, and determining whether or not the metal sheet has a processing defect based on the measured extent to which the radiated light spreads.

[0007] According to the laser processing machine and the processing defect detection method of one aspect of the present invention, it is judged whether or not the sheet metal has a processing defect based on the spread of the radiated light. Since the spread of the radiated light correlates with the state of the cut surface when laser cutting, it is possible to accurately judge the processing defect by judging the processing defect of the sheet metal based on the spread of the radiated light. Effect of the Invention

[0008] According to one aspect of the present invention, processing defects during laser cutting can be accurately determined, and erroneous detection of processing defects can be prevented. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the configuration of a laser processing machine according to the first embodiment. [Diagram 2] FIG. 2 is a diagram showing an example of an image captured by a camera provided in the laser processing machine according to the first embodiment. [Figure 3A] FIG. 3A is a diagram showing an example of an image capturing a change in the spread of emitted light when there is no processing defect. [Figure 3B] FIG. 3B is a diagram showing an example of the state of a cut surface of a metal sheet when there is no processing defect. [Figure 4A] FIG. 4A is a diagram showing an example of an image capturing a change in the spread of emitted light when a processing defect exists. [Figure 4B] FIG. 4B is a diagram showing an example of the state of a cut surface of a metal sheet when there is a processing defect. [Figure 4C]FIG. 4C is a diagram showing the depth and period of scratches formed on the cut surface of the metal sheet when there is a processing defect. [Diagram 5] FIG. 5 is a flowchart showing a processing procedure of the processing defect detection processing by the laser processing machine according to the first embodiment. [Figure 6] FIG. 6 is a diagram for explaining a method of measuring an angle by the laser processing machine according to the first embodiment. [Figure 7] FIG. 7 is a diagram showing a distribution of angles measured by the laser processing machine according to the first embodiment. [Figure 8] FIG. 8 is a diagram for explaining the width of spread of radiated light measured by the laser processing machine according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [First embodiment] [Laser processing machine configuration] Hereinafter, a laser processing machine and its processing defect detection method according to a first embodiment will be described with reference to the drawings. FIG. 1 is a diagram showing the configuration of the laser processing machine. As shown in FIG. 1, the laser processing machine 1 includes a processing head 3, a camera 5, a control unit 7, a laser oscillator 9, and an illumination device 11. The laser processing machine 1 is a device that emits a laser beam from the laser oscillator 9 to perform laser cutting on a metal sheet metal W.

[0011] The laser processing machine 1 includes a camera 5 that captures an image of radiation light emitted from a processing point of the metal sheet W when the metal sheet W is irradiated with a laser beam to cut it, and a control unit 7 that detects processing defects of the metal sheet W based on the radiation light captured by the camera 5. The control unit 7 measures the degree of spread of the radiation light in a direction perpendicular to the traveling direction of the laser beam, and judges whether or not the metal sheet W has been processed defectively based on the measured degree of spread of the radiation light.

[0012] The processing head 3 is connected to a laser oscillator 9 via a transmission fiber, and irradiates a laser beam emitted from the laser oscillator 9 toward the metal sheet W. Inside the processing head 3, a camera 5, a bandpass filter 13, an eyepiece 15, collimator lenses 17 and 19, a beam splitter 21, a bend mirror 23, and a focusing lens 25 are provided.

[0013] The camera 5 is disposed at the upper end inside the processing head 3, and captures the radiation light emitted from the processing point of the metal sheet W. When the metal sheet W is irradiated with a laser beam and radiation light is emitted from the processing point, the radiation light enters the camera 5 via the eyepiece 15 and the bandpass filter 13. At this time, the bandpass filter 13 transmits light of a specific wavelength band, and the eyepiece 15 is moved vertically to adjust the focus of the camera 5. The image captured in this manner is output to the control unit 7.

[0014] Fig. 2 is a diagram showing an example of a captured image captured by the camera 5. As shown in Fig. 2, the camera 5 captures an image of a processing point where the metal sheet W is irradiated with a laser beam, and the captured image captures the metal sheet W reflecting light from the lighting device 11 and radiant light 31 emitted when the metal sheet W is heated by the laser beam and reaches a high temperature.

[0015] The center 31A of the emitted light corresponds to the center of the laser beam. Since the upward direction in FIG. 2 is the direction in which the laser beam travels, the area above the center 31A of the emitted light is the front part 31B of the emitted light, and the area below the center 31A of the emitted light is the rear part 31C of the emitted light.

[0016] The front part 31B of the emitted light is a part located forward of the center 31A of the emitted light in the traveling direction, has a semicircular shape corresponding to the shape of the laser beam, and has a kerf 33 formed around its periphery.

[0017] The rear part 31C of the emitted light is a part behind the center 31A of the emitted light in the traveling direction, and is a part where the emitted light emitted when the metal sheet W is heated spreads rearward in the traveling direction as the laser beam travels.

[0018] The control unit 7 executes a process for detecting defects in processing of the metal sheet W based on the radiation imaged by the camera 5. Specifically, the control unit 7 measures the degree of spread of the radiation in a direction perpendicular to the traveling direction of the laser beam, and judges whether or not the metal sheet W is defective in processing based on the measured degree of spread of the radiation.

[0019] Fig. 3A is a diagram showing an example of an image capturing a change in the spread of the emitted light when there is no processing defect, and Fig. 3B is a diagram showing an example of the state of the cut surface of the metal sheet W when there is no processing defect. Fig. 3B shows a case where the metal sheet W is normally cut and the cut surface is smooth. Fig. 3A shows a number of consecutive frames at times t1 to t6 when the cut surface is smooth as shown in Fig. 3B, and the laser beam travels from left to right in Fig. 3A.

[0020] 3A, the spreading of the rear part 31C of the emitted light does not spread in a direction perpendicular to the traveling direction of the laser beam but remains almost constant. Moreover, the spreading of the rear part 31C of the emitted light does not change and remains stable among multiple frames from time t1 to t6.

[0021] On the other hand, Fig. 4A is a diagram showing an example of an image capturing a change in the spread of the emitted light when there is a processing defect, and Fig. 4B is a diagram showing an example of the state of the cut surface of the metal sheet W when there is a processing defect. Fig. 4B shows a case where the metal sheet W is abnormally cut and the cut surface is in a rough state. Fig. 4A shows a number of consecutive frames from time t1 to t6 when the cut surface is in a rough state as shown in Fig. 4B, and the traveling direction of the laser beam is from left to right in Fig. 4A.

[0022] 4A, the extent to which the rear part 31C of the synchrotron radiation spreads by a width h in a direction perpendicular to the traveling direction. This spreading width h is approximately 137 μm. In addition, between frames at times t1 to t6, the extent to which the rear part 31C of the synchrotron radiation spreads by the spreading width h and shrinks from the spreading width h repeatedly, with the fluctuation period being 904 μm.

[0023] Here, Fig. 4C is a diagram showing the measurement of the scratches formed on the cut surface of Fig. 4B. As shown in Fig. 4C, the depth of the scratches is 140 µm, and the scratch period is 950 µm. The spread width h of the rear part 31C of the synchrotron radiation is 137 µm, and the fluctuation period is 904 µm, so that the scratch depth and spread width h are almost the same, and the scratch period and the fluctuation period of the spread width h are also almost the same. As such, it is found that there is a correlation between the scratches formed on the cut surface and the spread width h, so that by measuring the spread of the rear part 31C of the synchrotron radiation, it is possible to detect processing defects on the cut surface of the sheet metal W.

[0024] Therefore, the control unit 7 determines that the metal sheet W is defectively machined when the change in the spread of the radiated light within a predetermined time is equal to or greater than a predetermined value. For example, the control unit 7 measures the angle at which the radiated light spreads in a direction perpendicular to the traveling direction of the laser beam as the spread of the radiated light, calculates a variance value from a plurality of angles measured within a predetermined time, and determines that the metal sheet W is defectively machined when the calculated variance value is equal to or greater than a predetermined value. The variance value may be a standard deviation, or may be a rate of change per unit time or a difference between previous and next frames. Furthermore, the metal sheet W may be defectively machined using a machine learning algorithm that uses the angle and the variance value as learning data.

[0025] The control unit 7 is configured by a computer having a memory, a processor such as a CPU (Central Processing Unit), and various interfaces. The memory and various interfaces are connected to the processor via a bus. The control unit 7 executes a processing defect detection process for detecting processing defects of the metal sheet W by executing a program stored in the memory by the processor. The control unit 7 may be provided in an NC (Numerical Control) device that controls the entire laser processing machine 1.

[0026] The laser oscillator 9 is a fiber laser oscillator or a YAG laser oscillator, etc., and oscillates a laser beam and supplies it to the processing head 3. The laser beam supplied from the laser oscillator 9 is converted into parallel light (collimated light) by a collimating lens 19, reflected by a bend mirror 23 and bent 90 degrees in its traveling direction, and focused by a focusing lens 25 to be irradiated onto the metal sheet W.

[0027] The lighting device 11 is composed of a plurality of light-emitting diodes (LEDs) and irradiates the metal sheet W with illumination light. The illumination light irradiated from the lighting device 11 is converted into parallel light (collimated light) by the collimator lens 17, reflected by the beam splitter 21 and bent 90 degrees in its traveling direction, and passes through the focusing lens 25 to be irradiated onto the metal sheet W. Note that the lighting device 11 does not necessarily have to be provided.

[0028] [Machining defect detection process] Next, a processing defect detection process by the laser processing machine 1 according to the first embodiment will be described. Fig. 5 is a flowchart showing a processing procedure of the processing defect detection process. The processing defect detection process starts when the laser processing by the laser processing machine 1 is started.

[0029] 5, in step S101, the control unit 7 acquires an image captured by the camera 5. When a laser beam is emitted from the laser oscillator 9, the camera 5 captures an image of the radiant light emitted from the processing point of the metal sheet W. The control unit 7 acquires the captured image output from the camera 5. The captured image may be temporarily stored in a memory (not shown) and the control unit 7 may acquire it from the memory.

[0030] In step S103, the control unit 7 measures the degree of spreading of the emitted light in a direction perpendicular to the traveling direction of the laser beam. Specifically, in the first embodiment, the angle at which the emitted light spreads in a direction perpendicular to the traveling direction of the laser beam is measured as the degree of spreading of the emitted light.

[0031] A specific method of measuring the angles will be described with reference to Fig. 6. As shown in Fig. 6, the control unit 7 binarizes the acquired image 61 and converts it into a binarized image 62. Next, the control unit 7 detects the center 31A of the radiated light from the binarized image 62, and extracts contours 63A, 63B that are located behind the center 31A of the radiated light with respect to the traveling direction of the laser beam. The control unit 7 performs linear estimation on the extracted contours 63A, 63B to detect straight lines 64A, 64B, and measures angles θL, θR that the straight lines 64A, 64B make with a direction perpendicular to the traveling direction of the laser beam. These angles θL, θR are the angles at which the radiated light spreads in a direction perpendicular to the traveling direction of the laser beam.

[0032] In step S105, the control unit 7 calculates a variance value of the angles measured in step S103. Specifically, the control unit 7 acquires angles for the past N frames, and calculates a variance value from a plurality of angles measured within a predetermined time.

[0033] In step S107, the control unit 7 judges whether the variance value calculated in step S105 is equal to or greater than a predetermined value. When there is no processing defect, the emitted light does not spread in a direction perpendicular to the traveling direction of the laser beam, and remains stable without change. On the other hand, when there is a processing defect, the emitted light spreads in a direction perpendicular to the traveling direction of the laser beam, and is not stable because it repeatedly spreads by the spread width and shrinks from the spread width. Therefore, when the variance value is calculated, it is a small value when there is no processing defect, and it is a large value when there is a processing defect.

[0034] For example, as shown in FIG. 7, when a distribution of angles measured in step S103 is created, it can be seen that the angle distribution 71 in the case of a good cut without processing defects is concentrated near 90 degrees, and therefore the variance value is small.

[0035] On the other hand, the angle distribution 72 in the case where cross-section roughness, a processing defect, occurs is mostly near 90 degrees, but is widely distributed from 70 degrees to 110 degrees, so it can be seen that the variance value is large. Furthermore, the angle distribution 73 in the case where burning, a processing defect, occurs, is widely distributed from 80 degrees to 120 degrees without being concentrated, so it can be seen that the variance value is large.

[0036] Since the variance value changes depending on the presence or absence of a processing defect in this way, a predetermined value is set in advance by experiment or simulation, and by comparing this predetermined value with the variance value, it is possible to determine whether or not there is a processing defect. In this way, in step S107, the variance value is compared with the predetermined value, and if the variance value is equal to or greater than the predetermined value, it is determined that there is a processing defect and the process proceeds to step S109, and if it is less than the predetermined value, it is determined that there is no processing defect and the process proceeds to step S117.

[0037] In step S109, the control unit 7 judges whether the user has set to continue the laser processing when it is determined that the metal sheet W is defective. The control unit 7 is set so that the user can select whether to continue the laser processing or to stop the laser processing when it is determined that the metal sheet W is defective. A user who thinks that even if there is a processing defect, it can be dealt with by post-processing selects to continue the laser processing, and a user who wants to immediately stop the processing when there is a processing defect selects to stop the laser processing. Therefore, if the user has set to continue the laser processing, the process proceeds to step S111, and if the user has set to stop the laser processing without continuing it, the process proceeds to step S113.

[0038] In step S111, the control unit 7 outputs a processing abnormality alarm indicating that a processing defect has occurred, notifies the user of the occurrence of the processing defect by an alarm display or a warning sound, and continues processing.

[0039] In step S113, the control unit 7 notifies the NC device to stop the laser processing by the laser processing machine 1. In step S115, the control unit 7 outputs a processing abnormality notification indicating that a processing defect has occurred, and notifies the user that the laser processing has been stopped due to the processing defect. When the processing abnormality notification is output, the processing defect detection process according to the first embodiment is terminated.

[0040] In step S117, the control unit 7 determines whether or not the laser processing by the laser processing machine 1 has been completed. If not, the process returns to step S101. If completed, the processing defect detection process according to the first embodiment is terminated.

[0041] [Variations] In the first embodiment, the angle at which the radiated light spreads in the vertical direction is measured, and the variance value of the angle is calculated to determine whether or not the metal sheet W is defectively machined. However, it is also possible to determine that the metal sheet W is defectively machined when the angle at which the radiated light spreads in the vertical direction is equal to or greater than a predetermined value without calculating the variance value.

[0042] That is, the control unit 7 measures the angle at which the radiated light spreads in a direction perpendicular to the traveling direction of the laser beam as the spread of the radiated light, and if the angle is equal to or greater than a predetermined value, it determines that the metal sheet W is defectively machined. In this case, in the flowchart of Fig. 5, the step of calculating the variance value in step S105 is deleted, and step S107 is changed to determine whether the angle is equal to or greater than a predetermined value.

[0043] [Effects of the first embodiment] As described above in detail, the laser processing machine 1 according to the first embodiment measures the degree of spread of the radiated light in the direction perpendicular to the traveling direction of the laser beam, and judges whether or not the metal sheet W is defectively processed based on the measured degree of spread of the radiated light. Since the degree of spread of the radiated light correlates with the state of the cut surface when laser cutting, if the processing defect of the metal sheet W is judged based on the degree of spread of the radiated light, the processing defect can be accurately judged. Therefore, the laser processing machine 1 according to the first embodiment can accurately judge the processing defect during laser cutting, and prevent erroneous detection of the processing defect.

[0044] Furthermore, the laser processing machine 1 according to the first embodiment measures the angle at which the radiated light spreads in a direction perpendicular to the traveling direction of the laser beam as the spread of the radiated light, calculates a dispersion value from a plurality of angles measured within a predetermined time, and judges that the metal sheet W has been processed poorly if the calculated dispersion value is equal to or greater than a predetermined value. By measuring the angle in this manner, the spread of the radiated light can be accurately measured, and by calculating the dispersion value, it is possible to accurately judge the processing defect even if the radiated light changes periodically.

[0045] Furthermore, the laser processing machine 1 according to the first embodiment measures the angle at which the radiated light spreads in a direction perpendicular to the traveling direction of the laser beam as the spread of the radiated light, and if the angle is equal to or greater than a predetermined value, it determines that the metal sheet W is defectively processed. By measuring the angle in this way, the spread of the radiated light can be accurately measured, and by determining the processing defect based on the angle, it is possible to easily determine the processing defect.

[0046] Furthermore, the laser processing machine 1 according to the first embodiment is set so that the user can select whether to continue the laser processing or to stop the laser processing when it is determined that the processing of the metal sheet W is defective. This allows the user to set how to deal with the occurrence of a processing defect according to their desire.

[0047] [Second embodiment] Hereinafter, the laser processing machine and the processing defect detection method thereof according to the second embodiment will be described with reference to the drawings. Note that the configuration of the laser processing machine 1 according to the second embodiment is the same as that of the first embodiment shown in FIG. 1, so detailed description thereof will be omitted.

[0048] In the first embodiment, the angle at which the emitted light spreads in a direction perpendicular to the laser beam propagation direction is measured as the spread of the emitted light. However, in the second embodiment, the width at which the emitted light spreads in a direction perpendicular to the laser beam propagation direction is measured as the spread of the emitted light, which is different from the first embodiment.

[0049] That is, the control unit 7 measures the width by which the emitted light spreads in a direction perpendicular to the direction of travel of the laser beam as the degree of spread of the emitted light, calculates a dispersion value from multiple widths measured within a specified time, and if the calculated dispersion value is equal to or greater than a specified value, determines that the sheet metal W is defectively processed.

[0050] As shown in FIG. 8, the control unit 7 measures a width L1 perpendicular to the traveling direction of the laser beam at the position of the center 31A of the emitted light, and a width L2 perpendicular to the traveling direction of the laser beam at the position of the rear part 31C of the emitted light.

[0051] The control unit 7 calculates the difference (L2-L1) between the measured widths L1 and L2. As a result, this difference is measured as the width L of the radiation spread in the direction perpendicular to the traveling direction of the laser beam, which is the spread of the radiation. When the width L is measured in this manner, the control unit 7 calculates a variance value from a plurality of widths L measured within a predetermined time, and if the calculated variance value is a predetermined value or more, it determines that the metal sheet W is defectively machined. Note that the spread width h shown in FIG. 4A may be used instead of the width L.

[0052] Therefore, in the second embodiment, step S103 in the flow chart shown in FIG. 5 may be modified so that the width L of the emitted light in the vertical direction is calculated as the degree of spread of the emitted light.

[0053] [Variations] In the second embodiment, the width L of the emitted light in the vertical direction is measured, and the variance value of the width L is calculated to determine whether or not the metal sheet W is defectively machined. However, it is also possible to determine that the metal sheet W is defectively machined when the width L is equal to or greater than a predetermined value without calculating the variance value.

[0054] That is, the control unit 7 measures the width of the emitted light in the direction perpendicular to the traveling direction of the laser beam as the degree of spread of the emitted light, and if the width is equal to or greater than a predetermined value, determines that the metal sheet W is defectively machined. In this case, the flow chart of Fig. 5 may be modified so that the step of calculating the variance value in step S105 is deleted and step S107 is modified so as to determine whether the width is equal to or greater than a predetermined value.

[0055] [Effects of the second embodiment] As described above in detail, the laser processing machine 1 according to the second embodiment measures the width by which the radiated light spreads in the direction perpendicular to the traveling direction of the laser beam as the degree of spread of the radiated light, calculates a dispersion value from a plurality of widths measured within a predetermined time, and judges that the metal sheet W has been processed poorly if the calculated dispersion value is equal to or greater than a predetermined value. By measuring the width by which the radiated light spreads in this way, the degree of spread of the radiated light can be accurately measured, and by calculating the dispersion value, it is possible to accurately judge the degree of processing defects even if the radiated light changes periodically.

[0056] Moreover, the laser processing machine 1 according to the second embodiment measures the width by which the radiated light spreads in a direction perpendicular to the traveling direction of the laser beam as the spread of the radiated light, and if the width is equal to or greater than a predetermined value, it determines that the metal sheet W is defectively processed. By measuring the width in this manner, the spread of the radiated light can be accurately measured, and by determining the processing defect based on the width, it is possible to easily determine the processing defect.

[0057] As described above, the embodiment of the present invention has been described, but the description and drawings forming a part of this disclosure should not be understood as limiting this invention. From this disclosure, various alternative embodiments, examples and operating techniques will become apparent to those skilled in the art. [Explanation of symbols]

[0058] 1 Laser processing machine 3 Processing head 5. Camera 7 Control section 9 Laser Oscillator 11 Lighting equipment 13 Bandpass Filter 15 Eyepiece 17, 19 Collimating lens 21 Beam splitter 23 Bend Mirror 25 Focusing Lens 31 Synchrotron Radiation 31A Synchrotron radiation center 31B Synchrotron radiation front part 31C Rear part of synchrotron radiation 33 Calf 61 images 62 Binarized Images 63A, 63B Contour 64A, 64B straight line 71, 72, 73 Angular distribution h Spread width L, L1, L2 width θL, θR angle

Claims

1. a camera that captures an image of radiation light emitted from a processing point of a metal sheet when the metal sheet is cut by irradiating the metal sheet with a laser beam; a control unit that detects a processing defect of the sheet metal based on the radiation light captured by the camera, The control unit measures how the emitted light spreads in a direction perpendicular to the traveling direction of the laser beam, and determines whether or not the metal plate is defective based on the measured spread of the emitted light. Laser processing machine.

2. The control unit measures an angle at which the radiated light spreads in a direction perpendicular to the traveling direction of the laser beam as a degree of spread of the radiated light, calculates a dispersion value from a plurality of the angles measured within a predetermined time, and determines that the sheet metal is defective when the calculated dispersion value is equal to or greater than a predetermined value.

2. The laser processing machine according to claim 1.

3. The control unit measures a width of the radiation light in a direction perpendicular to the traveling direction of the laser beam as a degree of spreading of the radiation light, calculates a dispersion value from a plurality of the widths measured within a predetermined time, and determines that the sheet metal is defective when the calculated dispersion value is equal to or greater than a predetermined value.

2. The laser processing machine according to claim 1.

4. The control unit measures an angle at which the radiated light spreads in a direction perpendicular to the traveling direction of the laser beam as a spread of the radiated light, and determines that the sheet metal is defective when the angle is equal to or greater than a predetermined value.

2. The laser processing machine according to claim 1.

5. The control unit measures a width of the radiation light in a direction perpendicular to the traveling direction of the laser beam as a degree of spreading of the radiation light, and if the width is equal to or greater than a predetermined value, determines that the sheet metal is defectively processed.

2. The laser processing machine according to claim 1.

6. The control unit is configured to allow a user to select whether to continue laser processing or stop laser processing when it is determined that the sheet metal is defective. The laser processing machine according to any one of claims 1 to 5.

7. When a laser processing machine irradiates a laser beam onto a metal plate to cut it, a camera captures an image of the radiation emitted from a processing point on the metal plate; measuring a degree of spreading of the imaged emitted light in a direction perpendicular to a traveling direction of the laser beam; Based on the measured spread of the emitted light, it is determined whether or not the metal plate is defective. Method for detecting machining defects.

Images