Fault Detection Device and Laser Processing System

Abstract

The failure detection device (1) includes a processing laser source (10), a detection laser source (20), an optical fiber (70), a laser head (80), a condenser lens (36), a second light receiver (110), a third light receiver (120), a fourth light receiver (130), a fifth light receiver (140), and a judgment unit (50). The processing laser source (10) emits processing laser light, and the detection laser source (20) emits detection laser light. A mode elimination unit (78) is provided near the incident end and the exit end of the optical fiber (70). The condenser lens (36) converges the processing laser light at the incident end of the optical fiber. The judgment unit (50) determines whether any of the processing states of the optical fiber, the condenser lens, the laser head, and the workpiece is defective based on the relative ratio of the intensities of the light measured by the second light receiver, the third light receiver, the fourth light receiver, and the fifth light receiver and the change in the intensity over time.

Description

Technical Field

[0001] The present disclosure relates to a fault detection device having an optical fiber and a laser processing system, and more particularly to a fault detection device and a laser processing system having an optical fiber capable of transmitting high-output processing laser light. Background Art

[0002] A laser processing system has been widely used, which transmits high-output processing laser light from a direct diode laser (DDL) light source or the like to a processing head through an optical fiber, converges and irradiates the laser light, and thereby performs welding, melting and piercing, etc. on a workpiece. In the process of transmitting the processing laser light through the optical fiber, if the optical fiber is broken, since the output energy of the processing laser light is large, it may cause damage to peripheral devices such as the coating resin of the optical fiber. Therefore, generally, in a laser processing system using high-output processing laser light, a device for detecting a break in the optical fiber for transmitting the laser light is provided.

[0003] Regarding devices for detecting a break in an optical fiber for transmitting high-output laser light, many proposals have been made so far. As a break detection device related to the prior art, the following devices have been proposed: for example, a closed loop is formed using a coated wire arranged along the optical fiber for transmitting the laser light, and the break (open circuit) or short circuit of the closed loop due to the heat generated when the optical fiber is broken is detected electrically, thereby detecting a break in the optical fiber.

[0004] Another break detection device has been proposed, in which a tube for circulating gas is arranged along the optical fiber instead of the coated wire, the flow rate of the circulating gas is monitored, and when the flow rate of the circulating gas changes, it is determined that the optical fiber is broken.

[0005] Another break detection device has been proposed. In a laser processing system that uses an optical fiber to transmit laser light (processing laser light) for processing a workpiece, it includes a pair of photodetectors that respectively monitor the light intensity (output intensity) of the processing laser light incident on and exiting from the optical fiber, and detects a break in the optical fiber or energy loss caused by the optical fiber based on the difference or change in the relative value of the light intensity of the processing laser light measured by each photodetector.

[0006] More specifically, the optical fiber break detection device described in Patent Document 1 includes an optical fiber, a pair of light receivers, and a detection unit. The optical fiber transmits high-energy processing laser light for processing a workpiece, the pair of light receivers are provided near the incident end and the exit end of the optical fiber, and the detection unit compares the outputs of the light receivers to detect a break in the optical fiber.

[0007] In addition, similarly, the optical fiber device for laser transmission described in Patent Document 2 includes an optical fiber, a visible light selective reflection unit, and a light receiving detector. The optical fiber transmits high-power laser for processing a workpiece. The visible light selective reflection unit is arranged near the emission end of the optical fiber, and the light receiving detector is arranged near the injection end of the optical fiber. The light receiving detector receives the high-power laser and the visible light selected by the visible light selective reflection unit. This visible light is generated when the coating material of the optical fiber burns due to optical fiber breakage or the like. Moreover, the optical fiber device for laser transmission detects abnormalities such as optical fiber breakage by comparing the light intensities of the high-power laser and the visible light.

[0008] Patent Document 1: Japanese Patent Laid-Open Publication No. Hei 10-038751

[0009] Patent Document 2: Japanese Patent Laid-Open Publication No. Hei 07-266067 Summary of the Invention

[0010] -Technical Problem to be Solved by the Invention-

[0011] However, in a wire breakage detection device using a coated wire or a gas circulation pipe, when a closed circuit of the coated wire independent of the optical fiber is broken, short-circuited, or the flow rate of the circulating gas changes, even if the optical fiber is not broken, it may sometimes be erroneously detected as an optical fiber breakage. For example, in a wire breakage detection device using a coated wire, when a pair of coated wires forming a closed circuit are peeled off due to friction with the optical fiber, sometimes the pair of core wires of the coated wire may come into contact (short-circuit), causing the wire breakage detection function to be activated.

[0012] In addition, the technologies described in Patent Document 1 and Patent Document 2 both use the high-output laser for processing a workpiece for wire breakage detection. Specifically, the processing laser injected into the optical fiber and the processing laser emitted from the optical fiber (Patent Document 1) or the high-power laser injected into the optical fiber and the visible light emitted from the optical fiber (Patent Document 2) are compared to detect optical fiber breakage. However, the output intensity of the laser (processing laser) for processing a workpiece varies depending on the operating state of the laser source device, the usage time, etc., and the transmittance of the optical fiber is substantially likely to change. Therefore, it is difficult to detect the transmission loss, etc. of the optical fiber itself using the optical fiber that transmits the processing laser, and false detection may occur.

[0013] In addition, generally, the wavelength bands of the processing laser (Patent Document 1) and the visible light generated by the burning of the coating material (Patent Document 2) are relatively wide, and it is easy to interfere with the Rayleigh scattered light generated in the optical fiber depending on the above wavelength and the composition of the optical fiber (the density of the glass molecules constituting the optical fiber) (scattered light generated by the light scattering phenomenon caused by particles smaller than the wavelength of light). The processing laser or the visible light is unstable, and false detection and the like may also occur sometimes.

[0014] In addition, Patent Documents 1 and 2 do not specifically disclose the following configuration, which can appropriately detect defects generated inside the processing system including the optical fiber itself and in the workpiece during laser processing using a laser processing system having an optical fiber.

[0015] - Technical Solution for Solving Technical Problems -

[0016] An aspect of the present disclosure relates to a fault detection device, which includes a processing laser source, a detection laser source, an optical fiber, a condenser lens, a second light receiver, a third light receiver, a fourth light receiver, a laser head, a fifth light receiver, and a judgment unit. The processing laser source emits processing laser light, the detection laser source emits detection laser light, the optical fiber transmits the second partial light of the detection laser light and the processing laser light, and a mode eliminating portion is provided near the incident end of the optical fiber, and another mode eliminating portion is provided near the exit end of the optical fiber. The condenser lens converges the second partial light and the processing laser light at the incident end of the optical fiber. The second light receiver is arranged near the condenser lens. The third light receiver is arranged near the mode eliminating portion and measures the intensity of the light released from the mode eliminating portion. The fourth light receiver is arranged near the other mode eliminating portion and measures the intensity of the light released from the other mode eliminating portion. The laser head is connected to the exit end of the optical fiber and emits the second partial light and the processing laser light toward the workpiece. The fifth light receiver is arranged inside the laser head. The judgment unit judges whether any of the processing states of the optical fiber, the condenser lens, the laser head, and the workpiece generates a defect based on the relative ratio of the intensities of the light measured by at least the second light receiver, the third light receiver, the fourth light receiver, and the fifth light receiver and the change of the intensity over time.

[0017] - Effects of the Invention -

[0018] The fault detection device according to the present disclosure can detect optical fiber breakage and other defects of the laser processing system with high reliability. Description of the Drawings

[0019] Figure 1 is a block diagram showing a simplified configuration of the fault detection device according to the embodiment;

[0020] Figure 2 is a diagram showing a simplified configuration of the optical fiber and its connection portion;

[0021] Figure 3 is along Figure 2 a schematic cross-sectional view taken along line III-III;

[0022] Figure 4It is a diagram showing the relationships between various defects and their symptoms of a laser processing system and a fault detection device and the measurement signals from a first photodetector, a second photodetector, a third photodetector, a fourth photodetector, and a fifth photodetector;

[0023] Figure 5 It is a diagram showing the relationships between various defects of a laser processing system and a fault detection device and the processing quality of a workpiece;

[0024] Figure 6 It is a block diagram showing a simplified configuration of the fault detection device according to a modified example;

[0025] Figure 7 It is a diagram showing the relationships between various defects and their symptoms of a laser processing system and a fault detection device and the measurement signals from a first photodetector, a second photodetector, a third photodetector, a fourth photodetector, a fifth photodetector, and a sixth photodetector. Detailed Description of the Invention

[0026] First, the simplified configuration of the present disclosure will be described. The fault detection device according to an aspect of the present disclosure includes a processing laser source, a detection laser source, a first light receiver, an optical fiber, and a laser head. The processing laser source emits processing laser light, the detection laser source emits detection laser light, the first light receiver measures the intensity of a first part of the detection laser light, the optical fiber transmits a second part of the detection laser light and the processing laser light, and a mode eliminating portion is provided near the incident end of the optical fiber, and another mode eliminating portion is provided near the exit end of the optical fiber. The laser head is connected to the exit end of the optical fiber and emits the second part of the detection laser light and the processing laser light toward the workpiece. The fault detection device further includes a condenser lens, a second light receiver, a third light receiver, a fourth light receiver, a fifth light receiver, and a determination unit. The condenser lens converges the second part of the detection laser light and the processing laser light at the incident end of the optical fiber. The second light receiver is arranged near the condenser lens, the third light receiver is arranged near the mode eliminating portion, the fourth light receiver is arranged near the other mode eliminating portion, the fifth light receiver is arranged inside the laser head, and the determination unit determines whether any of the optical fiber, the condenser lens, the laser head, and the processing state of the workpiece has a defect based on the relative comparison of the intensities of the light measured by at least the second light receiver, the third light receiver, the fourth light receiver, and the fifth light receiver and the change in the intensity over time.

[0027] Since the fault detection device according to this aspect has the above configuration, it is possible to appropriately determine the presence or absence and types of defects and their symptoms generated in the fault detection device, the laser processing system including it, and the laser processing. In addition, it is possible to perform maintenance on the defective parts of the fault detection device and the laser processing system at an appropriate time or to stop the laser processing system in advance to maintain the processing quality of the workpiece.

[0028] Hereinafter, embodiments of the fault detection device according to the present disclosure will be described with reference to the drawings. In the description of each embodiment, for ease of understanding, directional terms (such as "left side" and "right side") may be used as the case may be, but the above terms are for illustration purposes only and do not limit the present disclosure. It should be noted that in each drawing, the electrical connections of the components of the fault detection device are represented by solid lines, and the forward directions of the respective lasers from the components (such as light sources) are represented by straight arrows. In addition, in order to clearly show each laser in the drawings, the optical axes of the respective lasers are offset in the illustration, but in fact, the respective lasers are transmitted on the same optical axis in the optical fiber.

[0029] [Embodiment]

[0030] Hereinafter, with reference to Figures 1 to 5 , embodiments of the fault detection device 1 according to the present disclosure will be described. Figure 1 FIG. is a block diagram showing a simplified configuration of the fault detection device 1 according to the present embodiment. Figure 2 FIG. is a diagram showing a simplified configuration of the optical fiber 70 and its connection portion. Figure 3 is a schematic cross-sectional view taken along the Figure 2 III-III line.

[0031] As Figure 1 shown, the fault detection device 1 according to the embodiment generally includes a processing laser source 10, a detection laser source 20, an optical fiber 70, a first photodetector 100 (light receiver), a second photodetector 110 (light receiver), a third photodetector 120 (light receiver), a fourth photodetector 130 (light receiver), a fifth photodetector 140 (light receiver), a laser head 80, a first housing 160, and a defect determination unit (determination unit) 50. The laser processing system according to the present embodiment includes a fault detection device 1, a system control unit 60, a first storage chamber 16, and a second storage chamber 18. The first storage chamber 16 houses the processing laser source 10, the detection laser source 20, the first housing 160, the first photodetector 100, and the defect determination unit 50. In addition, the first housing 160 houses a half mirror 12, a condenser lens 36, and the second photodetector 110. In addition, the first housing 160 also indirectly houses the third photodetector 120.

[0032] It should be noted that here, indirectly housing means that after the third photodetector 120 is arranged in the cylindrical connection portion 161 at the end of the optical fiber 70 where the optical fiber 70 is installed, it is indirectly installed on the first housing 160. In other words, it is the following structure: the third photodetector 120 is built in the connection portion 161 at the end of the optical fiber 70, and the connection portion 161 of the optical fiber 70 is installed on the first housing 160.

[0033] The processing laser source 10 emits an arbitrarily high-output processing laser L for processing a workpiece (workpiece, not shown). P . The processing is, for example, welding, fusing, and perforating. The processing laser source 10 can be, for example, a direct diode laser (DDL) light source that emits a processing laser L with a relatively long peak wavelength, a relatively wide wavelength band (975 nm ± 20 nm), and an output intensity of several kilowatts (~10 4 W). P . As shown in the figure, the processing laser L P is reflected by the half mirror 12 and directed (guided) by the optical fiber 70. The half mirror 12 is arranged in a direction at a 45-degree angle to the optical axis of the processing laser L P . The half mirror 12 preferably totally reflects the light of the wavelength band of the processing laser L P substantially and totally transmits the light with a shorter wavelength such as the detection laser L D described later.

[0034] The detection laser source 20 emits a detection laser L D . The detection laser source 20 can be, for example, a helium-neon (He-Ne) laser source or a semiconductor laser source that emits a detection laser L with a shorter peak wavelength than the processing laser L P , a narrower wavelength band than the processing laser L P (600 nm ± 5 nm), and an output intensity of several hundred milliwatts (~1 W). D .

[0035] It should be noted that the first photodetector 100 is arranged near the light emitting portion of the detection laser source 20 and near the optical path of the detection laser L D . The second photodetector 110 is arranged between the condenser lens 36 and the entrance end 72 of the optical fiber 70 and near the optical paths of the processing laser L P and the detection laser L D . The third photodetector 120 is arranged inside the cylindrical connecting portion 161 provided on the first housing 160 and near the mode eliminating portion 78 of the optical fiber 70 (see Figure 2 ). Among them, the first photodetector 100 measures the light intensity of the first partial light L D of the detection laser L D1 and provides the measured signal P 10 to the defect determination unit 50. That is, the first photodetector 100 is provided to determine whether the detection laser L D is at a specified output.

[0036] The second photodetector 110 measures the light intensity of the following light, which is the second partial light L P of the processing laser L transmitted through the condenser lens 36 and the detection laser L D D2 ​Among them, light that deviates from the specified optical path. In addition, the second photodetector 110 measures the light intensity of the following light, which is the light reflected by the workpiece and returned to the inside of the first housing 160 through the laser head 80 and the optical fiber 70 and is reflected by the condenser lens 36. The signal P measured by the second photodetector 110 11 is supplied to the defect determination unit 50. It should be noted that the second photodetector 110 is set such that the light reception sensitivity to light having the same wavelength as the detection laser L D is higher than the light reception sensitivity to light having the same wavelength as the processing laser L P For example, when the second photodetector 110 is made of a semiconductor material, the light reception sensitivity can be set as described above by appropriately setting the semiconductor material. In addition, a band-pass filter may be arranged on or near the light receiving surface of the second photodetector 110, and the light reception sensitivity may be set as described above. The second photodetector 110 is mainly provided to determine whether contamination of the condenser lens 36 and optical fiber burnout described later occur. It should be noted that the third photodetector 120 will be described later.

[0037] It should be noted that the second partial light L of the present embodiment D2 is the light component that enters the optical fiber 70 other than the first partial light L D that enters the first photodetector 100 from the detection laser L D1 In order to make the first partial light L D of the detection laser L D1 enter the first photodetector 100, another half mirror (not shown) may be arranged between the detection laser source 20 and the half mirror 12, and the detection laser L D is divided into the first partial light L[[ID=2Q]] D1 and the second partial light L D2 .

[0038] The laser head 80 has a second housing 82, and the second housing 82 corresponds to the second storage chamber 18. The second housing 82 houses a collimator lens 84, a condenser lens 86, a protective glass 88, a fourth photodetector 130, and a fifth photodetector 140. The fourth photodetector 130 is arranged inside a cylindrical connecting portion 821 provided on the second housing 82 and near the mode eliminating portion 78 of the optical fiber 70 (see Figure 2 ). The fifth photodetector 140 is arranged inside the second housing 82 on the side where the connecting portion 821 is provided. The fifth photodetector 140 measures the light intensity of the following light, which is the processing laser L P reflected by the workpiece and entering the inside of the laser head 80 and the second partial light L D of the detection laser L D2In the return light, the light that deviates from the specified optical path. In addition, the fifth photodetector 140 measures the light intensity of the following light, which is the processing laser L reflected by the optical components (such as the protective glass 88) inside the laser head 80 P and the detection laser L D of the second partial light L D2 of the return light. The signal P measured by the fifth photodetector 140 14 is provided to the defect determination unit 50. The fifth photodetector 140 is mainly provided to determine whether there is contamination or the like in the optical components inside the laser head 80. It should be noted that the fourth photodetector 130 will be described later.

[0039] The optical fiber 70 physically and optically connects the first housing 160 and the second housing 82. The collimating lens 84 collimates the processing laser L P and the detection laser L D of the second partial light into parallel light, and the condensing lens 86 converges the processing laser L transmitted through the collimating lens 84 towards the workpiece P and the detection laser L D of the second partial light L D2 . The protective glass 88 prevents soot, spatter, etc. generated from the workpiece due to the irradiation of the processing laser L P from entering the inside of the second housing 82.

[0040] [Structure of the optical fiber and its connection part]

[0041] As Figure 2 shown, end caps 76 are respectively provided at the incident end 72 and the exit end 74 of the optical fiber 70. The end caps 76 are made of cylindrical quartz glass. The end caps 76 are respectively fusion-connected to the incident end 72 and the exit end 74 of the optical fiber 70.

[0042] The outer diameter of the end cap 76 is larger than the outer diameter of the second cladding 70d of the optical fiber 70 described later. The end cap 76 can reduce the energy density of the processing laser L P at the incident end 72 and the exit end 74 of the optical fiber 70, and respectively suppress damage to the incident end 72 and the exit end 74 of the optical fiber 70.

[0043] The end portion on the exit side of the optical fiber 70 is housed inside the connection portion 821 provided on the second housing 82. In the optical fiber 70 housed inside the connection portion 821, a mode stripper 78 is provided on the second cladding 70d that is exposed after removing a part of the coating portion 70e (refer to Figure 3 ).

[0044] In addition, the end portion on the incident side of the optical fiber 70 is housed inside the connection portion 161. In the optical fiber 70 housed inside the connection portion 161, a part of the coating portion 70e is removed (refer to Figure 3)On the exposed second cladding 70d, the mode eliminating portion 78 is provided. It should be noted that water cooling mechanisms (not shown) are respectively provided at the connecting portion 161 and the connecting portion 821 to cool the optical fiber 70 housed therein.

[0045] The mode eliminating portion 78 releases the processing laser L P and the detection laser L D released to the outside of the second cladding 70d for elimination. The mode eliminating portion 78 is formed, for example, by performing an etching process on the outer peripheral surface of the second cladding 70d. <(

[0046] The fourth photodetector 130 measures the light intensity of the following light and provides the measured signal P 13 to the defect judgment portion 50. This light is the processing laser L P and the detection laser L D of the second partial light L D2 or the light released from the mode eliminating portion 78 provided on the emission side of the optical fiber 70 in its return light.

[0047] The third photodetector 120 mainly measures the light intensity of the following light and provides the measured signal P 12 to the defect judgment portion 50. This light is the processing laser L P and the detection laser L D of the second partial light L D2 and is the light released from the mode eliminating portion 78 provided on the incident side of the optical fiber 70.

[0048] As Figure 3 shown, the optical fiber 70 has at least a first core 70a as an optical waveguide, a second core 70c as an optical waveguide path, a first cladding 70b, and a second cladding 70d. The outer peripheral surface of the second cladding 70d is covered with a light-shielding covering portion 70e.

[0049] The first core 70a is circular in cross-section and is arranged at the axis of the optical fiber 70. The first cladding 70b is in contact with the outer peripheral surface of the first core 70a, is coaxially arranged with the first core 70a, and is annular in cross-section. The second core 70c is in contact with the outer peripheral surface of the first cladding 70b, is coaxially arranged with the first core 70a, and is annular in cross-section. The second cladding 70d is in contact with the outer peripheral surface of the second core 70c, is coaxially arranged with the first core 70a, and is annular in cross-section.

[0050] The first core 70a, the second core 70c, the first cladding 70b, and the second cladding 70d are all formed of quartz. However, the refractive index of the first cladding 70b is set to be lower than the refractive indices of the first core 70a and the second core 70c, respectively. In addition, the refractive index of the second cladding 70d is set to be lower than the refractive index of the second core 70c. That is to say, the optical fiber 70 is a so-called multi-core optical fiber. The laser beams from multiple laser sources are combined to form the processing laser L P In the case of P , the beam profile of the processing laser L P sometimes greatly expands. By using the multi-core optical fiber as the optical fiber 70, even when the beam profile of the processing laser L P changes, the processing laser L can be reliably guided to the laser head 80

[0051] [Diagnosis of Defects and Defect Symptoms of Laser Processing System and Fault Detection Device]

[0052] The fault detection device 1 monitors the relative ratios of the measurement signals P 10 ~P 14 measured by the first photodetector 100, the second photodetector 110, the third photodetector 120, the fourth photodetector 130, and the fifth photodetector 140 and the changes of each signal over time. Moreover, the monitoring results are diagnosed by the defect determination unit 50, and considering the laser processing system and the fault detection device 1, the defects generated during laser processing (whether there are defects in any of the laser processing system and the fault detection device 1 such as the optical fiber 70, the condenser lens 36, the laser head 80, the processing laser source 10, etc. and the processing state of the workpiece) and their mutual relationships (the relative ratios of the intensities of the light measured by at least the second photodetector 110, the third photodetector 120, the fourth photodetector 130, and the fifth photodetector 140 and the changes of the intensity over time), the presence or absence and types of symptoms are determined. In this way, it is possible to maintain the defective part at an appropriate time or stop the system in advance to maintain the processing quality of the workpiece

[0053] Figure 4 is a diagram showing the relationships between various defects of the laser processing system and the fault detection device 1 and their symptoms and the measurement signals from the first photodetector 100, the second photodetector 110, the third photodetector 120, the fourth photodetector 130, and the fifth photodetector 140 Figure 5 is a diagram showing the relationships between various defects of the laser processing system and the fault detection device 1 and the processing quality of the workpiece. It should be noted that in the present embodiment, while the processing laser source 10 emits the processing laser L P and the detection laser source 20 emits the detection laser L DIn the state (start state), various malfunctions of the laser processing system and the fault detection device 1 and the presence or absence of malfunctions in laser processing are judged and diagnosed. In addition, in Figure 4 In the example shown, when each diagnostic item is normal, the measured signals P 10 ~P 14 are each set to "1". In addition, the measured signals P 10 ~P 14 when a malfunction occurs are relative values based on the values in the normal state.

[0054] It should be noted that the obtained measured signals P 10 ~P 14 are associated with the time elapsed since the start of laser irradiation, the subsequent diagnostic items, symptom patterns, and error patterns, and are stored as a history in a storage unit (not shown). At this time, according to a command from the system control unit 60, the measured signals P 10 ~P 14 can also be stored in the storage unit.

[0055] In Figure 4 , 5 In the example shown, seven types of diagnostic items related to malfunctions (hereinafter simply referred to as items) are cited. Each item will be described below. It should be noted that in the present embodiment, an "error" means a malfunction at a level that requires the laser processing system and the fault detection device 1 to stop working urgently in terms of safety or the processing quality of the workpiece to be processed, especially a malfunction at a level that requires the processing laser source 10 and the detection laser source 20 to stop working urgently. When the malfunction judgment unit 50 actually judges it as an error, the system control unit 60 stops at least the processing laser source 10 and the detection laser source 20. A "symptom" means a malfunction that does not cause the laser processing system and the fault detection device 1 to stop working, but may lead to an error if left unattended. In addition, in Figure 4 , the number of the detection mode is the same as the number after the error in the error record of the detection stage. The case where there are multiple detection modes is a case where malfunctions occur for various different reasons, and there are also multiple modes of the occurrence of errors. In addition, as a symptom in the detection stage, the letter after the symptom is the same as and corresponds to the letter after the symptom in the item number and the symptom pattern column before the occurrence in Figure 5 . When it is detected (judged) that the number of the measured signal value before the symptom continuously increases, the larger the number, the closer the degree of malfunction is to the symptom level. In addition, when it is detected (judged) that the number of the measured signal value after the symptom continuously increases, the larger the number, the closer the degree of malfunction is to the error level. In addition, in Figure 5 , the importance indicates the degree of influence on the laser processing system and the fault detection device 1 itself or on the processing quality of the workpiece to be processed. A smaller number indicates a greater degree of the above influence.

[0056] <A: Large reflected light from the workpiece>

[0057] Figure 4 、 5 The item number A shown corresponds to a defect where the intensity of the reflected light from the workpiece is greater than a specified value. As Figure 4 、 5 shown, for example, each symptom (symptom D, symptom G, symptom H) in this item number A indicates that a defect mainly caused by (corresponding to) item numbers D, G, and H has occurred. For example, if the intensity of the reflected light from the workpiece increases, the amount of light returning to the inside of the first housing 160 through the optical fiber 70 also increases. When the returned light is reflected by the condenser lens 36, the amount of light received by the second photodetector 110 increases, and it is determined that symptom D has occurred. This symptom pattern is a pattern corresponding to the contamination of the condenser lens 36. In addition, if the leakage light from the mode eliminating section 78 on the incident side increases, the amount of light received by the third photodetector 120 increases, and it is determined that symptom G has occurred. This symptom pattern is a pattern corresponding to the reduction in the coupling efficiency between the processing laser L P and the detection laser L D and the optical fiber 70. In addition, if the intensity of the reflected light from the workpiece increases and the scattering on the surface of the workpiece increases, for example, the amount of light received by the fifth photodetector 140 decreases, and it is determined that symptom H has occurred. This symptom pattern is a pattern corresponding to the reduction in the output of the processing laser source 10.

[0058] As Figure 4 shown, the error patterns generated after detecting each symptom are different, but in any case, once an error occurs, the processing quality of the workpiece will drop sharply. Therefore, when a symptom occurs, for example, the system control unit 60 causes a display unit (not shown) to display the occurrence and pattern of the symptom in an image or notify the occurrence and pattern of the symptom by sound or perform both of the above simultaneously. In this way, it is possible to appropriately give instructions to the processing operator, etc. regarding the maintenance period and maintenance location of the failure detection device 1 and the laser processing system. In addition, when symptom H (reduction in the output of the processing laser source 10) is detected, the following maintenance can also be performed, that is, adjusting the output current value of the processing laser source 10 to correct the output value of the processing laser L P to the set value. In this case, the system control unit 60 can also be provided with a power feedback function to automatically correct the output value of the processing laser L P

[0059] <B: Optical fiber burnout>

[0060] Figure 4 、 5 ​The item number B shown corresponds to the defect of the optical fiber 70 being burned out. If the amount of light passing through the first cladding 70b and / or the second cladding 70d without passing through the first core 70a and / or the second core 70c is excessive, the optical fiber 70 will heat up and be burned out, resulting in the inability to transmit light. As Figure 4 , 5 shown, the defects corresponding to item numbers C and G tend to occur as this symptom. For example, as shown in detection mode 1, if the optical components inside the laser head 80 (typically the protective glass 88) are severely contaminated, the processing laser L P and the detection laser L D will be reflected by the protective glass 88 and enter the optical fiber 70 as return light. If the intensity of this return light increases, for example, the light reception amounts of the first photodetector 100, the second photodetector 110, the fourth photodetector 130, and the fifth photodetector 140 increase, and it is determined that symptom C has occurred. This symptom mode corresponds to the contamination of the optical components inside the laser head 80. In addition, as shown in detection mode 2, if the processing laser L P has an optical axis deviation or the like, resulting in an increase in the amount of light passing through the claddings 70b and 70d of the optical fiber 70, the light reception amount of the third photodetector 120 increases, and a mode corresponding to a decrease in coupling efficiency (symptom G) is detected. It should be noted that this symptom mode is judged based on the change compared to when the measurement signal of a specific photodetector is normal. Therefore, even in symptom G corresponding to item number A (large reflected light from the workpiece) and symptom G corresponding to item number B (optical fiber burnout), the relative values between the measurement signals P 10 ~P 14 are slightly different, it will not affect the judgment of this symptom mode itself. The same applies to the examples shown later.

[0061] In addition, in detection mode 1 of item number B (optical fiber burnout), from the detection of symptom C to the burnout of the optical fiber, it is possible to further detect the symptom modes in the following two stages. First, a mode (symptom 1) in which the measurement signals P 13 and P 14 of the fourth photodetector 130 and the fifth photodetector 140 arranged on the output side of the optical fiber 70 increase significantly respectively is detected. This mode corresponds to symptom B of item number E described later. Symptom 1 indicates that the intensity of the reflected return light reflected by the optical components inside the laser head 80 such as the protective glass 88 increases. If this state continues, the following symptom mode (symptom 2) will be detected, which indicates that the output side of the optical fiber 70 is burned out, the optical fiber 70 is broken, and it may be impossible to continue transmitting the processing laser L P and the detection laser L DThis mode corresponds to errors E1 and F1 of item numbers E and F. In this case, the fourth photodetector 130 and the fifth photodetector 140 arranged on the outgoing side of the optical fiber 70 cannot receive the processing laser L P and the detection laser L D light, and the measurement signals P 13 、P 14 both become zero. If the state of sign 2 continues to be detected, due to the optical fiber melting phenomenon, the optical fiber 70 will burn to the incoming side, eventually resulting in the detection of an error (error B1 of item number B). If optical fiber burnout occurs, the processing laser L P cannot irradiate the workpiece, and laser processing of the workpiece cannot be performed. It should be noted that the optical fiber melting phenomenon refers to the following phenomenon, that is, due to the injection of high-power laser, the optical discharge (bright spot) generated on the optical fiber will transmit toward the light source side while damaging the optical fiber.

[0062] On the other hand, in detection mode 2 of item number B (optical fiber burnout), the situation where an error (error B2 of item number B (optical fiber burnout)) is detected after detecting the sign mode G (coupling efficiency reduction) indicates that: on the incoming side of the optical fiber 70, the coupling loss and transmission loss increase, and as a result, heat is generated on the incoming side of the optical fiber 70, causing burnout. In this way, according to the location and mode of optical fiber burnout, the change of the measurement signals P 10 ~P 14 over time and the sign modes and error modes associated with the measurement signals P 10 ~P 14 are different. Therefore, when an error related to item number B is detected, the processing operator can easily analyze the cause of the error according to the history of the measurement signals P 10 ~P 14 . In this way, the maintenance and recovery operations of the laser processing system and the fault detection device 1 can be carried out quickly and accurately, thereby reducing the downtime and maintenance cost.

[0063] It should be noted that according to this embodiment, in other items, the analysis of the cause of the error will obviously become easier. For example, for item number A (large reflected light from the workpiece), since multiple sign modes (sign D, sign G, sign H) can be detected until the error occurs, it is possible to easily determine the location where maintenance and confirmation operations need to be performed. In addition, for example, if the configuration in which only the first photodetector 100 and the second photodetector 110 are arranged in the fault detection device 1 is adopted, the type of defect cannot be determined according to the increase or decrease of the measurement signal P 11 output from the second photodetector 110. This is because, for example, it is impossible to distinguish the measurement signal P 11Is the reason for the increase the contamination of the condenser lens 36 (item number D), the reduction in the coupling efficiency of the optical fiber 70 (item number G), or the increase in the reflected light from the workpiece (item number A)? In particular, in the case of a multi-core optical fiber such as the optical fiber 70 in the present embodiment, the reflected light from the workpiece easily returns to the first housing 160. Therefore, it is more difficult to identify the type of the above-mentioned defect. In addition, since the output of the processing laser L P is very large, its variation is also large. When the second photodetector 110 receives the component due to the processing laser L P , the measurement signal P 11 will immediately saturate, and the measurement accuracy cannot be improved.

[0064] On the other hand, according to the present embodiment, based on the relative ratio of the measurement signals P 10 ~P 14 and the change of the measurement signals P 10 ~P 14 over time, etc., it is possible to easily determine the type of the defect and its generation location, etc. In particular, since the light receiving sensitivity of the second photodetector 110 is set as described above, the proportion of the component due to the detection laser L 11 in the measurement signal P D becomes larger. Therefore, since the proportion of the component due to the detection laser L D becomes larger, the saturation of the measurement signal P 11 can be suppressed, and the measurement accuracy can be improved. In this way, it is possible to reduce the downtime and maintenance cost of the laser processing system and the failure detection device 1.

[0065] <C: Contamination of the optical components in the laser head 80>

[0066] Figure 4 , 5 The item number C shown corresponds to the defect that the optical components (for example, the protective glass 88) in the laser head 80 are contaminated. For example, dust, spatter, etc. generated when the processing laser L P irradiates the workpiece adhere to the protective glass 88 and reach a specified amount or more. In this case, as described in the optical fiber burnout of item number B, affected by the reflected return light incident on the optical fiber 70, the light receiving amounts of the first photodetector 100, the second photodetector 110, the fourth photodetector 130, and the fifth photodetector 140 become larger, and the symptom C (contamination of the optical components in the laser head 80) is detected.

[0067] <D: Contamination of the condenser lens 36>

[0068] Figure 4 , 5The item number D shown corresponds to the defect of contamination generated by the condenser lens 36. In this case, as described above, the amount of light received by the second photodetector 110 mainly changes and increases, and the sign D is detected.

[0069] <E, F: Optical fiber breakage>

[0070] Figure 4 , 5 The item numbers E and F shown correspond to the defect of optical fiber 70 breakage. Among them, the item number F corresponds to the mechanical bending defect of the optical fiber 70, and the item number E corresponds to the state where optical transmission cannot be performed, and this state includes the bending defect of the optical fiber 70. As Figure 4 , 5 shown, the error E1 of optical fiber breakage (optical transmission cannot be performed) of item number E corresponds to symptom 2 in detection mode 1 of optical fiber burnout of item number B. In addition, symptom B of item number E corresponds to symptom 1 in detection mode 1 of optical fiber burnout of item number B. In addition, symptom C of item number E corresponds to the contamination of the optical components in the laser head 80 of item number C. Therefore, the said symptom B (optical fiber burnout) or symptom C (contamination of the optical components in the laser head 80), symptom B (optical fiber burnout) tend to continuously occur as symptoms of the error E1 of optical fiber breakage (optical transmission cannot be performed) of item number E. That is to say, as the previous stage (symptom) of the error E1 of item number E, an increase in the intensity of the reflected return light (measurement signals P 13 , P 14 ) reflected by the optical components inside the laser head 80 such as the protective glass 88 can be observed over time. It should be noted that in Figure 4 , the symptom B of optical fiber breakage (optical transmission cannot be performed) of item number E is taken as the mode corresponding to symptom 1 in detection mode 1 of optical fiber burnout of item number B. In addition, the error F1 of optical fiber breakage (mechanical bending) of item number F is the same as the error E1 of optical fiber breakage (optical transmission cannot be performed) of item number E, but for the optical fiber breakage (mechanical bending) of this item number F, the error often occurs suddenly without symptoms. For example, the case where the optical fiber 70 is bent by being suddenly contacted by other objects, etc.

[0071] Regarding item numbers E and F, detecting the errors E1 and F1 means that the processing laser L P and the detection laser L D cannot continue to be emitted from the optical fiber 70 to the laser head 80, and the situation is very serious. In addition, by Figure 4It can be clearly known that before the error related to the detection mode 1 of the optical fiber burnout of project number B, the errors E1 and F1 related to project numbers E and F as symptom 2 will be detected first. Therefore, for the above projects, regarding the symptom mode and its changes, it is necessary to check particularly carefully to prevent optical fiber breakage. In addition, after detecting the breakage, it is necessary to quickly stop the laser processing system and eliminate the cause of the defect.

[0072] <G: Decrease in coupling efficiency>

[0073] Figure 4 、 5 The project number G shown corresponds to a decrease in the coupling efficiency of the processing laser L P and the detection laser L D to the optical fiber 70. For example, due to the misalignment of the optical axes of the processing laser L P and the detection laser L D with the axis of the optical fiber 70, etc., the coupling efficiency decreases. In this case, for example, the processing laser L P and the detection laser L D are reflected at the incident end 72 of the optical fiber 70, and the light receiving amount of the second photodetector 110 increases, detecting symptom D (contamination of the condenser lens 36). If this state continues, the amount of light leaking from the mode eliminating portion 78 on the incident side of the optical fiber 70 will increase, and the measurement signal P 12 of the third photodetector 120 will become larger. In addition, correspondingly, the amount of light transmitted to the output side of the optical fiber 70 will become smaller. That is, the measurement signals P 13 、P 14 of the fourth photodetector 130 and the fifth photodetector 140 will become smaller. This state is detected as symptom G (decrease in coupling efficiency).

[0074] <H: Decrease in the output of the processing laser source 10>

[0075] Figure 4 、 5 The project number H shown corresponds to a decrease in the output of the processing laser source 10. For example, due to certain reasons, the output current value of the processing laser source 10 decreases, and the light amount of the processing laser L P decreases. In this case, the measurement signal P D of the first photodetector 100 for detecting the first part of the light L D1 of the detection laser L 10 will not change. On the other hand, as the light amount of the processing laser L P decreases, the measurement signals measured by the photodetectors farther away from the processing laser source 10 become smaller. In the example shown in Figure 4 , the measurement signals P of the third photodetector 120, the fourth photodetector 130, and the fifth photodetector 14012 and P 13 and P 14 decreases and is detected as symptom H (decrease in the output of the processing laser source 10).

[0076] It should be noted that the defects related to item numbers C, D, G, and H do not immediately cause a major failure in the laser processing system and the failure detection device 1. However, as described above, if this state continues, it may lead to insufficient penetration depth at the processing site. Therefore, when any one of the symptoms C, D, G, and H is detected, it is preferable to notify the judgment result of the defect judgment unit 50 and notify the processing operator of the parts and periods that need maintenance in the form of an image or sound or both by the system control unit 60.

[0077] As described above, according to the failure detection device 1 of the present embodiment, the defect is not detected only by the measurement signal of a single photodetector at a specified time, but in cooperation with the time change, the plurality of measurement signals measured simultaneously and over time by the plurality of photodetectors arranged at specified positions are monitored. Thus, the defect judgment unit 50 can judge from multiple aspects whether any of the laser processing system such as the optical fiber 70, the condenser lens 36, the laser head 80, the processing laser source 10, and the internal and processing states of the failure detection device 1 and the workpiece generates a defect or the cause of the defect generation.

[0078] In addition, various defects often occur in the failure detection device 1 and the laser processing system. According to the present embodiment, even if various defects occur, they are rarely overlooked. In this way, unnecessary maintenance operations and recurrence of errors can be prevented. In addition, when multiple defects occur, there is a tendency for processing operators, etc. to only focus on one obvious defect. However, in this way, the symptoms that may develop into serious failures are often overlooked. On the other hand, according to the present embodiment, regarding the occurrence of defects, the data collection and analysis can be performed in consideration of temporal reasons such as changes over time and the spatial layout of the failure detection device 1 and the laser processing system. Therefore, the occurrence of serious failures can be prevented without overlooking the symptoms that may develop into serious failures.

[0079] In addition, the third photodetector 120 measures the intensity of the light released from the mode stripper 78 provided near the incident end 72 of the optical fiber 70. Based on the light intensities measured by the second photodetector 110 and the third photodetector 120 and the change of the intensity over time, the defect judgment unit 50 can judge the processing laser L P and the detection laser L D and the presence or absence of symptoms D and G of a decrease in the coupling efficiency with the optical fiber 70. Specifically, as Figure 4 shown, when the laser processing system is operating, if the measurement signal P of the second photodetector 110 11and the measurement signal P of the third photodetector 120 12 If at least one of them is larger than the normal condition (=1), it is determined that the processing laser L P and the detection laser L D show signs of reduced coupling efficiency with the optical fiber 70.

[0080] The fourth photodetector 130 measures the intensity of the light released from the mode eliminating section 78 provided near the emission end 74 of the optical fiber 70. Based on the intensity of the light measured by the fourth photodetector 130 and the fifth photodetector 140 and the change of this intensity over time, the defect judgment section 50 can judge the presence or absence of various defects and their signs in the processing system and the fault detection device 1. In particular, by simultaneously using the measurement signal P 13 of the fourth photodetector 130 14 and the measurement signal P Figure 4 as shown, when the measurement signal P 13 of the fourth photodetector 130 14 and the measurement signal P 13 of the fifth photodetector 140 14 are both smaller than the normal condition (=1), it can be judged that signs G and H have occurred. In particular, when neither the measurement signal P 13 nor the measurement signal P 14 is detected, it can be judged that either a break or burnout of the optical fiber 70 (error E1, F1) or a sign C thereof has occurred. When the measurement signal P 13 and the measurement signal P 14 are both larger than the normal condition (=1), it can be judged that either sign C or error A1, A2 has occurred. When the measurement signal P 13 is larger than the normal condition (=1) while the measurement signal P 14 is smaller than the normal condition (=1), it can be judged that error A3 has occurred. In addition, by simultaneously using the measurement signal P 13 and the measurement signal P 14 , the reliability of the measurement can be improved, and further the judgment accuracy of the above-mentioned defects and their signs can be improved.

[0081] <Variant Example>

[0082] Next, with reference to Figure 6 , 7 the fault detection device 1 according to this variant example will be described. Figure 6It is a block diagram showing a simplified configuration of the failure detection device 1 according to this modification example. Figure 7 It shows the various defects of the laser processing system and the failure detection device 1, their symptoms, and the relationship with the measurement signals from the first photodetector 100, the second photodetector 110, the third photodetector 120, the fourth photodetector 130, the fifth photodetector 140, and the sixth photodetector 150.

[0083] The failure detection device 1 shown in this modification example further has a sixth photodetector (sixth light receiver) 150 inside the first housing 160, which is different from the failure detection device 1 shown in Figure 1 In addition, the half mirror 12 allows a part of the light in the wavelength band of the processing laser L P to pass through. For example, the half mirror 12 allows light in the range of about zero point a few percent to a few percent to pass through. On the optical path of the processing laser L passing through the half mirror 12, the sixth photodetector 150 is arranged. That is, the sixth photodetector 150 measures the intensity of a part of the light of the processing laser L P According to the measured intensity, the output of the processing laser L P is evaluated to determine whether the output is the set value. In addition, in the example shown in P , the sixth photodetector 150 is arranged inside the first housing 160 and near the optical paths of the processing laser L Figure 6 and the detection laser L P respectively. Therefore, as shown in D , the sixth photodetector 150 can detect the reflected return light from the optical components inside the work piece and the laser head 80. So, the sixth photodetector 150 can detect the errors A1 to A3. In addition, it can detect the symptom C related to the burnout of the optical fiber 70 and the errors B1 and B2. Figure 7 That is, in the failure detection device 1 according to this modification example, the defect judgment unit 50 judges the defects and their symptoms of the laser processing system and the failure detection device 1 based on at least the relative ratio of the intensities of the light measured by the second photodetector 110, the third photodetector 120, the fourth photodetector 130, the fifth photodetector 140, and the sixth photodetector 150 and the change of the intensity over time. Preferably, the defect judgment unit 50 judges the defects of the laser processing system and the failure detection device 1 based on the relative ratio of the intensities of the light measured by the first photodetector 100, the second photodetector 110, the third photodetector 120, the fourth photodetector 130, the fifth photodetector 140, and the sixth photodetector 150 and the change of the intensity over time. In addition, the defect judgment unit 50 judges the processing laser L based on the intensity of the light measured by the sixth photodetector 150 and the change of the intensity over time.

[0084] That is to say, in the failure detection device 1 according to this modification example, the defect judgment unit 50 judges the defects and their symptoms of the laser processing system and the failure detection device 1 based on at least the relative ratio of the intensities of the light measured by the second photodetector 110, the third photodetector 120, the fourth photodetector 130, the fifth photodetector 140, and the sixth photodetector 150 and the change of the intensity over time. Preferably, the defect judgment unit 50 judges the defects of the laser processing system and the failure detection device 1 based on the relative ratio of the intensities of the light measured by the first photodetector 100, the second photodetector 110, the third photodetector 120, the fourth photodetector 130, the fifth photodetector 140, and the sixth photodetector 150 and the change of the intensity over time. In addition, the defect judgment unit 50 judges the processing laser L based on the intensity of the light measured by the sixth photodetector 150 and the change of the intensity over time.P Whether it is a specified output. By disposing the sixth photodetector 150 at the said position, it is possible to directly detect the output change of the processing laser L P . In addition, it is possible to improve the determination accuracy of the said sign H.

[0085] It should be noted that the detection laser source 20 of the present disclosure can also be used as a teaching light source for the processing part. For example, when the second housing 82 of the laser head 80 is mounted on a robot arm (not shown) to perform laser processing on a workpiece, the detection laser L which is visible light is irradiated onto the workpiece D , and it can be seen through a camera or the like. Teach the movement of the robot arm so that the detection laser L D draws a specified trajectory on the workpiece.

[0086] -Industrial Applicability-

[0087] The present disclosure can be used in a failure detection device in a laser processing system for transmitting high-output processing laser.

[0088] -Symbol Explanation-

[0089] 1 Failure detection device

[0090] 10 Processing laser source

[0091] 12 Half mirror

[0092] 20 Detection laser source

[0093] 36 Condensing lens

[0094] 50 Defect determination unit (determination unit)

[0095] 60 System control unit

[0096] 70 Optical fiber

[0097] 72 Injection end

[0098] 74 Ejection end

[0099] 78 Mode elimination unit

[0100] 80 Laser head

[0101] 82 Second housing

[0102] 821 Connection part

[0103] 84 Collimating lens

[0104] 86 Condensing lens

[0105] 88 Protective glass

[0106] 100 First photodetector (light receiver)

[0107] 110 Second photodetector (light receiver)

[0108] 120 Third photodetector (light receiver)

[0109] 130 Fourth photodetector (light receiver)

[0110] 140 Fifth photodetector (light receiver)

[0111] 150 Sixth photodetector (light receiver)

[0112] 160 First housing

[0113] 161 Connecting part

[0114] L P Processing laser

[0115] L D Detection laser

[0116] L D1 First partial light

[0117] L D2 Second partial light

Claims

1. A fault detection device, characterized in that: The fault detection device includes a processing laser source, a detection laser source, an optical fiber, a condenser lens, a second light receiver, a third light receiver, a fourth light receiver, a laser head, a fifth light receiver, and a judgment unit. The processing laser source emits processing laser light. The detection laser source emits detection laser light. The optical fiber transmits the second part of the detection laser light and the processing laser light, and a mode eliminating part is provided near the incident end of the optical fiber, and another mode eliminating part is provided near the exit end of the optical fiber. The condenser lens converges the second part of the light and the processing laser light at the incident end of the optical fiber. The second light receiver is arranged near the condenser lens. The third light receiver is arranged near the mode eliminating part and measures the intensity of the light released from the mode eliminating part. The fourth light receiver is arranged near the other mode eliminating part and measures the intensity of the light released from the other mode eliminating part. The laser head is connected to the exit end of the optical fiber and emits the second part of the light and the processing laser light toward the workpiece. The fifth light receiver is arranged inside the laser head. The judgment unit judges whether any of the processing states of the optical fiber, the condenser lens, the laser head, and the workpiece is defective based on the relative ratio of the light intensities measured by at least the second light receiver, the third light receiver, the fourth light receiver, and the fifth light receiver and the change of the intensity over time. The relative ratio of the light intensities is the relative value of the light intensities based on the measured values in the normal state.

2. The fault detection device according to claim 1, characterized in that: The judgment unit judges the signs of the defect based on the relative ratio of the light intensities measured by at least the second light receiver, the third light receiver, the fourth light receiver, and the fifth light receiver and the change of the intensity over time.

3. The fault detection device according to claim 1, characterized in that: The second core of the optical fiber is coaxial with the first core and is provided on the outer peripheral side of the first core with a predetermined distance, the second core has the first core as an optical waveguide at its axis, and the second core is annular when viewed in cross section and serves as an optical waveguide.

4. The fault detection device according to claim 1, characterized in that: The fault detection device further includes a first light receiver that measures the intensity of the first part of the detection laser light. The judgment unit judges the defect and the signs of the defect based on the relative ratio of the light intensities measured by the first light receiver, the second light receiver, the third light receiver, the fourth light receiver, and the fifth light receiver and the change of the intensity over time. Moreover, based on the intensity of the light measured by the first light receiver and the change of the intensity over time, it is judged whether the detection laser has a specified output.

5. The fault detection device according to claim 4, characterized in that: The first light receiver is set such that the light receiving sensitivity to light having the same wavelength as the detection laser is higher than the light receiving sensitivity to light having the same wavelength as the processing laser.

6. The fault detection device according to claim 1, wherein: Based on the intensity of the light measured by the second light receiver and the third light receiver and the change of the intensity over time, it is determined whether there are signs of a decrease in the coupling efficiency between the processing laser and the detection laser and the optical fiber.

7. The fault detection device according to claim 1, wherein: Based on the intensity of the light measured by the fourth light receiver and the fifth light receiver and the change of the intensity over time, it is determined whether there are any defects and signs of defects caused by an increase in the reflected return light from the workpiece, contamination of the optical components inside the laser head, or burnout and disconnection of the optical fiber.

8. The fault detection device according to claim 1, wherein: The fault detection device further includes a sixth light receiver for measuring the intensity of a part of the processing laser, The determination unit determines the defects and signs of defects based on the relative ratio of the intensities of the light measured by at least the second light receiver, the third light receiver, the fourth light receiver, the fifth light receiver, and the sixth light receiver and the change of the intensity over time, Moreover, based on the intensity of the light measured by the sixth light receiver and the change of the intensity over time, it is determined whether the processing laser is at a specified output.

9. The fault detection device according to claim 1, wherein: In a state where the processing laser and the detection laser are emitted simultaneously, the intensities of the light are measured by at least the second light receiver, the third light receiver, the fourth light receiver, and the fifth light receiver, The determination unit determines whether there are any defects and signs of defects based on the relative ratio of the measured intensity of the light and the change of the intensity over time.

10. A laser processing system, characterized in that: The laser processing system includes: The fault detection device according to any one of claims 1 to 9, and A control unit for controlling the fault detection device.

11. The laser processing system according to claim 10, wherein: When the determination unit determines that there is a defect in either the optical fiber or the processing state of the workpiece, The control unit stops at least the processing laser source and the detection laser source in the fault detection device.

12. The laser processing system according to claim 10, wherein: When the determination unit determines that there are signs of a defect in either the optical fiber, the condenser lens, the laser head, or the processing state of the workpiece, The control unit notifies the determination result determined by the determination unit or stores the determination result in a storage unit, or performs both of the above.

13. The laser processing system according to claim 12, wherein: The control unit corrects the output of the processing laser according to the determination result determined by the determination unit or notifies the maintenance location and the maintenance time, or performs both of the above.

Images