JPWO2019059249A1 - Failure detection device, laser machining system and failure detection method - Google Patents

Abstract

The failure detection device (1) divides the processing laser light source (10) that emits the processing laser light, the detection laser light source (20) that emits the detection laser light, and the detection laser light into the first and second partial lights. The spectroscope (22), the first receiver (24) that measures the intensity of the first partial light of the detection laser light, and the optical fiber that transmits the second partial light of the detection laser light and the processed laser light. (30), the second receiver (26) for measuring the intensity of the second partial light transmitted by the optical fiber, and the first and second portions measured by the first and second receivers. A determination unit (50) for determining whether or not there is a defect in the optical fiber based on the relative ratio of light intensity is provided.

Description

The present disclosure relates to an optical fiber failure detection device, a laser processing system and a failure detection method, and more particularly to an optical fiber failure detection device, a laser processing system and a failure detection method for transmitting high-power processed laser light.

High-power processed laser light from a direct diode laser (DDL) light source, etc. is transmitted to the processing head via an optical fiber, and is focused and irradiated to weld and fusing the workpiece. Laser processing systems such as these are widely used. In such an optical fiber, if the optical fiber is disconnected while transmitting the processed laser light, the output energy of the processed laser light is large, so that there is a risk of damaging peripheral devices such as the coating resin of the optical fiber. Therefore, a laser processing system that utilizes high-power processed laser light is generally provided with a device for detecting a disconnection of an optical fiber that transmits the laser light.

Many devices for detecting disconnection of an optical fiber that transmits high-power laser light have been proposed so far. As a disconnection detection device according to the prior art, for example, a closed circuit is configured by using a coated electric wire arranged along an optical fiber that transmits laser light, and the closed circuit is disconnected (open) due to heat generated when the optical fiber is disconnected. Alternatively, a method has been proposed in which a disconnection of an optical fiber is detected by electrically detecting a short circuit.

Yet another disconnection detector places a tube that circulates the gas along the optical fiber in place of the covered wire, monitors the flow rate of the circulating gas, and breaks the optical fiber when the flow rate of the circulating gas changes. Something to judge is also proposed.

Another disconnection detection device is a laser processing system in which laser light (processed laser light) for processing a work material is transmitted by an optical fiber, and the light intensity of each of the processed laser light incident and emitted from the optical fiber ( It is equipped with a pair of optical detectors that monitor the output intensity), and based on the difference in the optical intensity of the processed laser light measured by each optical detector or the change in the relative value, the disconnection of the optical fiber or the energy loss due to the optical fiber is detected. Those that detect are also used.

More specifically, the optical fiber fracture detection device described in Patent Document 1 includes an optical fiber that transmits high-energy processed laser light for processing a material to be processed, and the vicinity of an incident end and an emitted end of the optical fiber. It is provided with a pair of light receivers and a detection unit that detects breakage of an optical fiber by comparing the outputs of these light receivers.

Similarly, the optical fiber device for laser transmission described in Patent Document 2 includes an optical fiber that transmits power laser light for processing a work material and visible light selection that is arranged near the emission end of the optical fiber. It includes a reflecting means and a light receiving detector which is arranged near the incident end of the optical fiber and receives visible light selected by the power laser light and the visible light selective reflecting means. This visible light is generated by burning the coating material of the optical fiber due to disconnection of the optical fiber or the like. Then, the optical fiber device for laser transmission detects an abnormality such as a disconnection of the optical fiber by comparing the light intensities of the power laser light and the visible light.

Japanese Unexamined Patent Publication No. 10-038751 Japanese Unexamined Patent Publication No. 07-266067

However, in the disconnection detection device using the coated electric wire or the gas circulation tube, even if the optical fiber is not disconnected, the closed circuit of the coated electric wire separate from the optical fiber is disconnected or short-circuited, or the circulating gas When the flow rate changes, it may be erroneously detected that the optical fiber is broken. For example, in a disconnection detection device using a coated wire, when a pair of coated wires constituting a closed circuit are peeled off due to friction with an optical fiber, a pair of core wires of the coated wire come into contact (short circuit) and the disconnection detection function operates. Sometimes.

Further, the techniques described in Patent Document 1 and Patent Document 2 both utilize a high-power laser for processing a work material for disconnection detection. Specifically, the processed laser light incident on and emitted from the optical fiber (Patent Document 1), the power laser light incident on the optical fiber and the visible light emitted from the optical fiber (Patent Document 2) are compared. , Detects disconnection of optical fiber. However, the output intensity of the laser beam (processed laser beam) for processing the material to be processed fluctuates depending on the operating state or usage time of the laser light source device, and the transmittance of the optical fiber changes substantially. It's easy to do. Therefore, it becomes difficult to detect the transmission loss or the like of the optical fiber by using the optical fiber itself that transmits the processed laser light, which may lead to erroneous detection or the like.

Further, the processed laser light (Patent Document 1) and the visible light generated by burning the coating material (Patent Document 2) generally have a wide wavelength band, and these wavelengths and the composition of the optical fiber (glass molecules constituting the optical fiber). It easily interferes with Rayleigh scattered light (scattered light generated by the scattering phenomenon of light by particles smaller than the wavelength of light) generated in the optical fiber depending on the density), and the processed laser light or visible light is not stable. , Similarly, it may lead to false detection.

The first aspect according to the present disclosure relates to a failure detection device for an optical fiber, and the failure detection device uses a processing laser light source that emits a processing laser light, a detection laser light source that emits a detection laser light, and a detection laser light. A spectroscope that divides the first and second partial lights, a first receiver that measures the intensity of the first partial light of the detection laser light, and a second partial light and a processed laser light of the detection laser light. The optical fiber to be transmitted, the second receiver for measuring the intensity of the second partial light transmitted by the optical fiber, and the first and second partial lights measured by the first and second receivers. A determination unit for determining whether or not there is a defect in the optical fiber based on the relative strength ratio is provided.

A second aspect according to the present disclosure relates to a failure detection device for an optical fiber, in which the failure detection device uses a processing laser light source that emits processing laser light, a detection laser light source that emits detection laser light, and a detection laser light. A spectroscope that divides the first and second partial lights, a first receiver that measures the intensity of the first partial light of the detection laser light, and a second partial light and a processed laser light of the detection laser light. The optical fiber to be transmitted, the reflecting part that reflects the second partial light transmitted by the optical fiber toward the optical fiber, and the reflected light of the second partial light that is reflected by the reflecting part and transmitted by the optical fiber. A defect in the optical fiber based on the relative ratio of the intensity of the reflected light of the first partial light and the second partial light measured by the third receiver for measuring the intensity and the first and third receivers. It is provided with a determination unit for determining whether or not there is.

A third aspect according to the present disclosure relates to a failure detection device for an optical fiber, in which the failure detection device uses a processing laser light source that emits processing laser light, a detection laser light source that emits detection laser light, and a detection laser light. A spectroscope that divides the first and second partial lights, a first receiver that measures the intensity of the first partial light of the detection laser light, and a second partial light and a processed laser light of the detection laser light. The optical fiber to be transmitted and the second partial light transmitted by the optical fiber are partially reflected toward the optical fiber and partially transmitted, and the reflection-transmitting portion and the second partial light transmitted by the reflection-transmitting portion are transmitted. A second receiver that measures the intensity of the transmitted light of the partial light, and a third receiver that measures the intensity of the reflected light of the second partial light that is reflected by the reflected transmitting portion and transmitted by the optical fiber. Whether or not there is a defect in the optical fiber based on the relative ratio of the intensity of the transmitted light and the reflected light of the first partial light and the second partial light measured by the first, second and third receivers. It is provided with a determination unit for determining whether or not.

The failure detection device according to the present disclosure can detect disconnection of an optical fiber with higher reliability by using a stable detection laser light transmitted by an optical fiber instead of a processed laser light.

FIG. 1 is a block diagram showing a schematic configuration of a failure detection device according to the first embodiment. FIG. 2 is a block diagram showing a schematic configuration of the failure detection device according to the second embodiment. FIG. 3 is a block diagram showing a schematic configuration of the failure detection device according to the third embodiment.

First, the schematic structure of the present disclosure will be described. The failure detection device according to each aspect of the present disclosure includes a processed laser light source that emits processed laser light, a detection laser light source that emits detection laser light, and a spectrum that divides the detected laser light into first and second partial lights. It includes a device, a first receiver for measuring the intensity of the first partial light of the detection laser light, and an optical fiber for transmitting the second partial light of the detection laser light and the processed laser light.

The failure detection device according to the first aspect includes a second receiver for measuring the intensity of the second partial light transmitted by the optical fiber, and first and first receivers measured by the first and second receivers. It is provided with a determination unit for determining whether or not there is a defect in the optical fiber based on the relative ratio of the intensity of the partial light of 2. The detection laser beam has a shorter peak wavelength and a smaller half width (a wavelength width that is half the peak value of the peak wavelength and indicates the degree of spread in the wavelength direction) as compared with the processed laser beam. (Narrower wavelength band), lower output intensity. Further, the detection laser light (and thus, the second partial light) has a smaller loss of light intensity generated during transmission by the optical fiber and is more stable than the processed laser light. The wavelength dependence of the transmission loss of an optical fiber mainly depends on the material of the optical fiber. Further, the peak wavelength of the detection laser light mainly differs depending on the light source of the detection laser light. By appropriately selecting the light source of the detection laser light, it is possible to obtain the detection laser light having a smaller loss of light intensity in the optical fiber than the processed laser light. Since the determination unit according to the first aspect uses stable detection laser light, it is configured to detect defects such as disconnection of the optical fiber with high reliability.

The failure detection device according to the second aspect has a reflecting portion that reflects the second partial light transmitted by the optical fiber toward the optical fiber, and a second portion that is reflected by the reflecting portion and transmitted by the optical fiber. Based on the relative ratio of the intensity of the reflected light of the first partial light and the second partial light measured by the third receiver, which measures the intensity of the reflected light of light, and the first and third receivers. , A determination unit for determining whether or not there is a defect in the optical fiber is provided. Since the determination unit according to the second aspect uses stable detection laser light, it is configured to detect defects such as disconnection of the optical fiber with high reliability. Further, the electrical wiring distance for transmitting a signal indicating the difference in light intensity from the third photodetector to the defect determination unit can be shortened, and the configuration of the failure detection device can be simplified. ..

The failure detection device according to the third aspect has a reflection / transmission unit that partially reflects the second partial light transmitted by the optical fiber toward the optical fiber and partially transmits the light, and a reflection / transmission unit. A second receiver that measures the intensity of the transmitted light of the second partial light that has passed through, and a third that measures the intensity of the reflected light of the second partial light that is reflected by the reflected and transmitted portion and transmitted by the optical fiber. On the optical fiber based on the relative ratio of the intensity of the transmitted light and the reflected light of the first partial light and the second partial light measured by the receiver and the first, second and third receivers. It is provided with a determination unit for determining whether or not there is a defect. The determination unit according to the third aspect is a combination of the first and second aspects, and uses stable detection laser light, so that defects such as disconnection of the optical fiber can be detected with high reliability. It is configured as follows.

Next, an embodiment of the optical fiber failure detection device according to the present disclosure will be described with reference to the accompanying drawings. In the description of each embodiment, directional terms (eg, "left side" and "right side", etc.) are used as appropriate for ease of understanding, but these terms are for illustration purposes only. It does not limit disclosure. In each drawing, the electrical connection of each component of the optical fiber failure detection device is shown by a solid line, and the traveling direction of each laser beam from each component (light source, etc.) is shown by a straight arrow. Further, the straight line arrows in each drawing are shown by shifting these optical axes in order to clarify each laser beam, but in reality, each laser beam is transmitted on the same optical axis in the optical fiber. It is a thing.

[Embodiment 1]
The first embodiment of the failure detection device 1 according to the present disclosure will be described with reference to FIG. FIG. 1 is a block diagram showing a schematic configuration of the failure detection device 1 according to the present disclosure. As shown in FIG. 1, the failure detection device 1 according to the first embodiment generally includes a processed laser light source 10, a detection laser light source 20, a half mirror 22 (spectrometer), and an optical fiber 30 (process fiber or transmission). It also includes a fiber), first and second optical detectors 24 and 26 (receivers), and a defect determination unit 50 (simply also referred to as a determination unit). The laser processing system according to the present disclosure includes a processing laser light source 10 of the failure detection device 1 and a system control unit 60 electrically connected to the failure determination unit 50. The laser machining system has a first containment chamber 16 and a second containment chamber 18 separate from the first containment chamber 16. The first accommodation chamber 16 accommodates a processed laser light source 10, a detection laser light source 20, half mirrors 12, 22, a first photodetector 24, a condenser lens 36, and a defect determination unit 50. The second accommodation chamber 18 accommodates the second photodetector 26, the collimation lens 38, and the beam splitter 40. The optical fiber 30 physically and optically connects the first accommodation chamber 16 and the second accommodation chamber 18. The first accommodation room 16 is, for example, a space defined by the housing of the device or the room of the building. The same applies to the second containment chamber 18.

Processing laser light source 10 emits any processing laser light L _P of the high output for machining a workpiece (workpiece, not shown). Processing is, for example, welding, fusing and drilling. Processing laser light source 10 is, for example, the peak wavelength is long, wide wavelength band (975 nm ± 20 nm), direct diode laser (DDL output intensity emits a processing laser beam _{L P} of several kW order ^{(to 10} 4 W) ) It may be a light source. Processing laser beam L _P, as shown, is reflected by the half mirror 12 arranged in the direction of 45 degrees to the optical axis of the processing laser light L _P, it is oriented along the optical fiber 30 (guide). Half mirror 12 is substantially totally reflects the light of the wavelength band of the processing laser light L _P, that a short light more wavelengths, such as detection laser light L _D will be described later is intended to substantially totally transmits preferable.

Detection laser light source 20 emits the detection laser beam L _D for detecting a defect such as disconnection of the optical fiber 30. Detection laser light source 20, for example, the processing laser beam _L shorter peak wavelength than the _P, narrow wavelength band (600 nm ± 5 nm), helium for emitting a detection laser beam output intensity several hundred millimeters W (to 1 W) It may be a neon (He-Ne) laser light source or a semiconductor laser light source. Detection laser light L _D, as shown, in the drawing the lower left-facing surface S ₁ of another half mirror 22 arranged in the direction of 45 degrees with respect to the optical axis (spectrometer), is a part It reflects and the rest is transmitted. That detection laser light _{L D} is divided by the surface _{S 1} of the half mirror 22 to the first partial light _{L D1} and second partial light _{L D2.} Second partial light L _D2 transmitted is incident on the optical fiber 30 to the machining laser beam L _P coaxially, the first partial light L _D1 reflected is incident on the first photodetector 24.

The first photodetector 24 receives the first partial light L _D1 of the detection laser light L _D and measures the light intensity of the first partial light L _D1 . The first photodetector 24 provides a signal P ₁ indicating the light intensity of the first partial light L _D1 measured in fault determination unit 50.

A condenser lens 36 is arranged between the half mirror 12 and the optical fiber 30. Condenser lens 36 is for condensing the second partial light L _D2 and the processing laser light L _P of the detection laser beam L _D on the entrance end 32 of the optical fiber 30. Second partial light L _D2 and the processing laser light L _P of the detection laser light L _D emitted from the emission end 34 of the optical fiber 30 is converted into parallel light by a collimation lens 38, the optical axis of the optical fiber 30 It is incident on the beam splitter 40 arranged at an orientation of 45 degrees.

Beam splitter 40 is substantially totally reflects toward the light of the second partial light L _D2 equivalent wavelength band of the detection laser beam L _D to the second photodetector 26, equivalent to the processing laser beam L _P Light in the wavelength band of is substantially totally transmitted. That is, the second partial light L _D2 of the detection laser light L _D is incident on the second photodetector 26, and the processed laser light L _P is irradiated to the material to be processed. Although not shown, another condensing lens for condensing the second partial light _LD2 may be arranged between the beam splitter 40 and the second photodetector 26.

Second photodetector 26 receives the second partial light L _D2 of detection laser light L _D, as well as measuring the light intensity of the second partial light L _D2, the signal P ₂ indicating the light intensity It is supplied to the defect determination unit 50. Defect determination unit 50 compares the signals P _1, P ₂ showing the light intensity supplied from the first and second photodetectors 24 and 26, whether there has been a problem such as disconnection in optical fiber 30 judge. For example, when the intensity ratio (r ₁ = P ₂ / P ₁ ) of the signals P ₁ and P ₂ is smaller than the threshold value Th ₁ (r ₁ <Th ₁ ), the defect determination unit 50 determines that the optical fiber 30 has a defect. You may. When the optical fiber 30 is broken, typically, not the second partial light L _D2 of the processing laser light L _P and the detection laser light L _D is emitted from the exit end 34 of optical fiber 30, the signal P _second intensity is substantially zero, the intensity ratio r ₁ is also zero. At this time, the defect determination unit 50 can determine that the optical fiber 30 is broken. Incidentally, fault determination unit 50, instead of the intensity ratio of signals _P 1, _{P 2,} may determine the defect based on the intensity difference between the signals _P 1, _{P 2.} Furthermore, defect determination unit 50 may determine the fault based on the change in the change or intensity difference signal P _1, the intensity ratio of P _2. In short, the defect determination unit 50 determines whether or not there is a defect or a sign of a defect in the optical fiber 30 based on the relative ratio of the intensities of the first and second partial lights L _D1 and L _D2 , or A defect or a sign of a defect is determined based on a change in the relative ratio or a change in the relative difference of the intensities of the first and second partial optical fibers L _D1 and L _{D 2} .

Further, when dirt or the like adheres to the incident end 32 or the emitted end 34 of the optical fiber 30, the intensity ratio r ₁ of the signals P ₁ and P ₂ does not become zero, but the defect determination unit 50 determines the signals P ₁ and P. by comparing the intensity ratio of ₂ r ₁ and a suitable threshold value Th _1, the processing laser light L _P is irradiated to the dirt, the state where the incident end 32 or exit end 34 of optical fiber 30 is excessively heating problem It can be appropriately determined as a state. Unlike the background technique described above, the failure detection device 1 according to the present disclosure does not detect a disconnection of a coated electric wire separate from the optical fiber 30, but detects a laser beam transmitted to the optical fiber 30 itself. To do. Further, the processed laser has a wide wavelength band, and the output intensity tends to be unstable due to the operating state or the usage time of the processed laser light source. Failure detection device 1, rather than such a processing laser utilizes a detection laser beam L _D. Therefore, defects such as disconnection of the optical fiber 30 can be detected or determined with higher reliability.

The ratio of stable detection laser beam L intensity of the signal P ₂ showing the light intensity of the _D emitted from the signal P _1, and an optical fiber showing the light intensity of the detection laser light L _D is incident on the optical fiber 30 , Differences, or changes in relative values can be used to detect defects such as disconnection of the optical fiber 30 with high reliability.

When a defect determination unit 50 determines that the disconnection or failure occurs in the optical fiber 30, the system control unit 60 controls the processing laser light source 10 to stop immediately the exit of the processing laser light L _P high power by, damages such as a peripheral device by the working laser beam L _P leaked from the optical fiber 30 can be prevented.

[Embodiment 2]
A second embodiment of the failure detection device 2 according to the present disclosure will be described with reference to FIG. FIG. 2 is a block diagram showing a schematic configuration of the failure detection device 2 according to the present disclosure. The failure detection device 2 according to the second embodiment generally includes a third photodetector 28 that detects a second partial light _LD2 reciprocating in the optical fiber 30 instead of the second photodetector 26. Since it has the same configuration as that of the first embodiment except for the above points, the description of the overlapping points will be omitted. The third photodetector 28 is housed in the first containment chamber 16.

The failure detection device 2 according to the second embodiment is roughly the same as that of the first embodiment, that is, the processed laser light source 10, the detection laser light source 20, the half mirror 22 (spectrometer), the optical fiber 30, and the first. It includes an optical detector 24 (receiver) and a defect determination unit 50 (determination unit). These configurations and functions are the same as those in the first embodiment.

The failure detection device 2 according to the second embodiment is a diffraction grating plate 42 (also referred to as a grating or a reflection unit) arranged perpendicular to the optical axis of the optical fiber 30 shown on the right side of the collimation lens 38 shown in FIG. .) Is provided. Diffraction grating plate 42 in FIG. 2, substantially to the total transmitted light of the processing laser light L _P equivalent wavelength band, the light of the second partial light L _D2 equivalent wavelength band of the detection laser beam L _D It is substantially totally reflected toward the exit end 34 of the optical fiber 30. Although different from that shown in Figure 2, the diffraction grating plate 42, of the second partial light L _D2 of detection laser light L _D, is transmitted through a portion of the constant ratio, emitting the remainder of the optical fiber 30 It may be one that reflects toward the end 34. At this time, the relative intensity ratio of the transmitted light transmitted by the second partial light _LD2 through the diffraction grating plate 42 and the reflected light reflected by the diffraction grating plate 42 is constant.

Moreover, the second partial light L _D2 of detection laser light L _D emitted from the incident end 32 of the optical fiber 30 is a view in the right upwardly facing surface S ₂ of the half mirror 22 (spectrometer), partially reflecting And the rest is transparent. However, in FIG. 2, of the second partial light L _D2 , the straight arrow indicating the transmitted light transmitted through the half mirror 22 is omitted. That is, the second partial light _{L D2} of detection laser light _{L D} is an optical fiber 30 reciprocates, a part of the light (third partial light _{L D3)} is reflected by the surface _{S 2} of the half mirror 22 , Incidents on the third light detector 28.

The third photodetector 28 receives the third partial light L _D3 of the detection laser light L _D and measures the light intensity thereof. The third photodetector 28 supplies a signal P ₃ indicating the light intensity of the third partial light L _D3 measured in fault determination unit 50.

Fault determining unit 50 according to the second embodiment compares the signals P _1, P ₃ indicating the light intensity supplied from the first and third photodetectors 24 and 28, such as disconnection in optical fiber 30 Determine if there is a problem. For example, when the intensity ratio (r ₂ = P ₃ / P ₁ ) of the signals P ₁ and P ₃ is smaller than the threshold value Th ₂ (r ₂ <Th ₂ ), the defect determination unit 50 determines that the optical fiber 30 has a defect. You may. When the optical fiber 30 is broken, typically, the third never partial light L _D3 is emitted from the incident end 32 of the optical fiber 30, the intensity of the signal P ₃ of the detection laser light L _D is approximately It is zero, and the intensity ratio r ₂ is also zero. At this time, the defect determination unit 50 can determine that the optical fiber 30 is broken.

Further, when dirt or the like adheres to the incident end 32 or the emitted end 34 of the optical fiber 30, the intensity ratio r ₂ of the signals P ₁ and P ₃ does not become zero, but the defect determination unit 50 determines the signals P ₁ and P. by comparing the ₃ intensity ratio r ₂ with a suitable threshold value Th _2, the processing laser light L _P is irradiated to the dirt, the state where the incident end 32 or exit end 34 of optical fiber 30 is excessively heating problem It can be appropriately determined as a state. Fault detection apparatus 2 according to the present disclosure, as described above, by utilizing the detection laser light L _D is a stable detection laser light is transmitted into the optical fiber 30 itself, a problem such as disconnection of the optical fiber 30 It can be detected or judged with higher reliability.

Further, the light intensity of the detection laser light L _D is transmitted back and forth between the signal P ₁ indicating the light intensity of the detection laser light L _D is incident on the optical fiber _30, and the incident end of the optical fiber and the emitting end can be detected in each of the ratio of light intensity, the difference or change in the relative value, high reliability problem such as disconnection of the optical fiber 30 on the basis of, of the signal P ₃ indicating the.

In the second embodiment, unlike the first embodiment, both the first and third photodetectors 24 and 28 can be arranged adjacent to the defect determination unit 50. Specifically, the first and third photodetectors 24 and 28 are both housed in the first storage chamber 16. The defect determination unit 50 is also housed in the first storage chamber 16. That is, the third photodetector 28 according to the second embodiment can be arranged closer to the defect determination unit 50 than the second photodetector 26 of the first embodiment. Therefore, the third can be shortened electrical wiring distance for transmitting the signals P ₃ to the fault determining unit 50 from the photodetector 28, it is possible to further simplify the configuration of the failure detection device 2.

When such a defect determination unit 50 determines that the disconnection or failure occurs in the optical fiber 30, the system control unit 60, processing laser light source to stop immediately the exit of the processing laser light L _P high power by controlling the 10, the damage such as the peripheral device according to the working laser beam L _P leaked from the optical fiber 30 can be prevented.

[Embodiment 3]
A third embodiment of the failure detection device 3 according to the present disclosure will be described with reference to FIG. FIG. 3 is a block diagram showing a schematic configuration of the failure detection device 3 according to the present disclosure. The failure detection device 3 according to the third embodiment is generally implemented except that the second photodetector 26 of the first embodiment is provided with the third photodetector 28 of the second embodiment. Since it has the same configuration as that of Form 1, the description of overlapping points will be omitted.

The failure detection device 3 according to the third embodiment is roughly the same as that of the first embodiment, that is, the processed laser light source 10, the detection laser light source 20, the half mirror 22 (spectrometer), the optical fiber 30, and the first. It includes an optical detector 24 (receiver) and a defect determination unit 50 (determination unit). These configurations and functions are the same as those in the first embodiment.

The failure detection device 3 according to the third embodiment is a diffraction grating plate 42 (both a grating and a transmission reflection unit) arranged perpendicular to the optical axis of the optical fiber 30 shown on the right side of the collimation lens 38 shown in FIG. ) Is provided. The diffraction grating plate 42 of FIG. 3 transmits a part (transmitted light L _D2T ) of the second partial light L _D2 of the detection laser light L _D , and the rest (reflected light L _D2R ) is an optical fiber. It reflects toward the exit end 34 of 30.

The transmitted light _LD2T transmitted by the diffraction grating plate 42 of FIG. 3 is incident on the second photodetector 26 via the beam splitter 40 as in the first embodiment. Further, the reflected light L _D2R reflected by the diffraction grating plate 42 in Figure 3, is transmitted back to the optical fiber 30, as in the second embodiment, in the drawing the right upwardly facing surface S ₂ of the half mirror 22 (spectrometer) It is reflected and incident on the third photodetector 28.

The second optical detector 26 that receives the detection laser light on the emission end 34 side of the optical fiber 30 and the third optical detector 28 that receives the detection laser light of the incident end 32 of the optical fiber 30 are the first embodiment. Similar to 2 and 2, the transmitted light L _D2T and the reflected light L _D2R of the second partial light L _D2 of the detection laser light L _D are received, the light intensity thereof is measured, and the signal P ₂ , indicating the light intensity thereof. supplying P ₃ to the fault determination unit 50.

Fault determining unit 50 according to the third embodiment, first, by comparing the signals _{P 1,} P 2, _{P 3} indicating the supplied light intensity from the second and third photodetectors 24, 26, 28 , It is determined whether or not there is a problem such as disconnection in the optical fiber 30. In the defect determination unit 50, for example, when the intensity ratios (r ₁ = P ₂ / P ₁ , r ₂ = P ₃ / P ₁ ) of the signals P ₁ , P ₂ , and P ₃ are smaller than the threshold values Th ₁ and Th ₂ , respectively ( It may be determined that there is a problem in the optical fiber 30 with r ₁ <Th ₁ , r ₂ <Th ₂ ). When the optical fiber 30 is broken, typically, the light intensity of the transmitted light _{L D2T} and the reflected light _{L D2R} of the second partial light _{L D2} is substantially zero, the intensity ratio _r 1, _{r 2} also It is zero. At this time, the defect determination unit 50 can determine that the optical fiber 30 is broken.

Also, if the dirt on the incident end 32 or exit end 34 of optical fiber 30 is attached, the intensity ratio _r 1, _{r 2} of the signals _{P 1,} P 2, _{P 3} are not zero, fault determination unit 50 , by comparing the signals _{P 1,} P 2, the intensity ratio _r 1 of _{P 3, r 2} with an appropriate threshold value _Th 1, Th _2, the processing laser light _{L P} is irradiated to the dirt, the optical fiber 30 It is possible to appropriately determine a state in which the incident end 32 or the outgoing end 34 of the above heats up excessively as a defective state. Failure detection apparatus 3 according to the present disclosure, as described above, by utilizing the detection laser light L _D is a stable detection laser light is transmitted into the optical fiber 30 itself, a problem such as disconnection of the optical fiber 30 It can be detected or judged with higher reliability.

The signal P ₁ indicating the light intensity of the detection laser light L _D is incident on the optical fiber _30, the signal P ₂ exhibits a stable light intensity of the detection laser beam L _D was emitted from the optical _fiber, and incident optical fiber the ratio of the respective light intensity of the signal P ₃ indicating the light intensity of the detection laser light L _D is transmitted back and forth between the end and the exit end, differences or changes in the relative values, of the optical fiber 30 based on, Problems such as disconnection can be detected with high reliability.

Further, since the failure detection device 3 according to the third embodiment includes the third photodetector 28 of the second embodiment in addition to the second photodetector 26 of the first embodiment, the light Whether or not the fiber 30 is broken can be determined more reliably.

With such fault determination unit 50 determines the disconnection or the like of the optical fiber 30, the system control unit 60 controls the processing laser light source 10, immediately stop the emission of the processing laser light L _P high power processing laser damage such as a peripheral device by the light L _P can be prevented.

The present disclosure can be used for a failure detection device and a failure detection method for an optical fiber that transmits high-power processed laser light.

1, 2, 3 Optical fiber failure detection device 10 Processed laser light source 12 Half mirror S ₁ , S ₂ Half mirror surface 20 Detection laser light source 22 Half mirror 24 First light detector 26 Second light detector 28 No. 3 Optical detector 30 Optical fiber 32 Incident end 34 Exit end 36 Condensing lens 38 Collimation lens 40 Beam splitter 42 Diffraction lattice plate 50 Defect determination unit (judgment unit)
60 system control unit _{L P} processing laser beam _{L D} detection laser light _{L D1} first partial light _{L D2} second partial light _{L D3} third partial light _{L D2R} the second partial light reflected light _{L D2T} second Transmitted light of partial light

Claims (11)

A processed laser light source that emits processed laser light,
A detection laser light source that emits detection laser light and
A spectroscope that divides the detected laser light into first and second partial lights, and
A first receiver that measures the intensity of the first partial light of the detection laser light, and
An optical fiber that transmits the second partial light of the detection laser light and the processed laser light, and
A second receiver that measures the intensity of the second partial light transmitted by the optical fiber, and
A determination unit for determining whether or not there is a defect in the optical fiber based on the relative ratio of the intensities of the first and second partial lights measured by the first and second receivers is provided. Failure detection device. A processed laser light source that emits processed laser light,
A detection laser light source that emits detection laser light and
A spectroscope that divides the detected laser light into first and second partial lights, and
A first receiver that measures the intensity of the first partial light of the detection laser light, and
An optical fiber that transmits the second partial light of the detection laser light and the processed laser light, and
A reflecting unit that reflects the second partial light transmitted by the optical fiber toward the optical fiber.
A third receiver that is reflected by the reflecting unit and measures the intensity of the reflected light of the second partial light transmitted by the optical fiber, and
Based on the relative ratio of the intensities of the reflected light of the first partial light and the second partial light measured by the first and third receivers, it is determined whether or not there is a defect in the optical fiber. A failure detection device provided with a determination unit. A processed laser light source that emits processed laser light,
A detection laser light source that emits detection laser light and
A spectroscope that divides the detected laser light into first and second partial lights, and
A first receiver that measures the intensity of the first partial light of the detection laser light, and
An optical fiber that transmits the second partial light of the detection laser light and the processed laser light, and
A reflection-transmitting portion that partially reflects and partially transmits the second partial light transmitted by the optical fiber toward the optical fiber.
A second receiver for measuring the intensity of the transmitted light of the second partial light transmitted by the reflection transmitting portion, and a second receiver.
A third receiver that measures the intensity of the reflected light of the second partial light that is reflected by the reflection-transmitting portion and transmitted by the optical fiber, and
The optical fiber is based on the relative ratio of the intensity of the first partial light and the transmitted light and the reflected light of the second partial light measured by the first, second and third receivers. A failure detection device provided with a determination unit for determining whether or not there is a problem with the light. The second partial light of the detection laser light has a smaller loss of light intensity while being transmitted by the optical fiber than the processed laser light.
The failure detection device according to any one of claims 1 to 3. The detection laser light has a shorter peak wavelength, a smaller full width at half maximum, and a smaller output intensity than the processed laser light.
The failure detection device according to any one of claims 1 to 4. The failure detection device according to any one of claims 1 to 5.
A laser machining system including the failure detection device and a control unit that controls the machining laser light source. The process of emitting the detection laser light and
The process of emitting processed laser light and
The step of dividing the detection laser light into the first and second partial lights, and
The step of measuring the intensity of the first partial light of the detection laser light, and
A step of transmitting the second partial light of the detection laser light and the processed laser light by an optical fiber, and
A step of measuring the intensity of the second partial light transmitted by the optical fiber, and
A failure detection method comprising a step of determining whether or not there is a defect in the optical fiber based on the measured relative ratio of the intensities of the first and second partial lights. The process of emitting the detection laser light and
The process of emitting processed laser light and
The step of dividing the detection laser light into the first and second partial lights, and
The step of measuring the intensity of the first partial light of the detection laser light, and
A step of transmitting the second partial light of the detection laser light and the processed laser light by an optical fiber, and
A step of reflecting the second partial light transmitted by the optical fiber toward the optical fiber, and
A step of reflecting the light toward the optical fiber and measuring the intensity of the reflected light of the second partial light transmitted by the optical fiber.
A failure detection method including a step of determining whether or not there is a defect in an optical fiber based on the relative ratio of the measured intensities of the first partial light and the reflected light of the second partial light. .. The process of emitting the detection laser light and
The process of emitting processed laser light and
The step of dividing the detection laser light into the first and second partial lights, and
The step of measuring the intensity of the first partial light of the detection laser light, and
A step of transmitting the second partial light of the detection laser light and the processed laser light by an optical fiber, and
A step of partially reflecting the second partial light transmitted by the optical fiber toward the optical fiber and partially transmitting the light.
The step of measuring the intensity of the transmitted light of the second partial light that has been partially transmitted, and
A step of measuring the intensity of the reflected light of the second partial light transmitted by the optical fiber, which is partially reflected, and
A step of determining whether or not there is a defect in the optical fiber based on the relative ratio of the measured intensities of the first partial light and the transmitted light and the reflected light of the second partial light. Failure detection method with. Any one of claims 7 to 9, wherein the second partial light of the detection laser light has a smaller loss of light intensity while being transmitted by the optical fiber than the processed laser light. The failure detection method described in the section. The detection laser light has a shorter peak wavelength, a smaller full width at half maximum, and a smaller output intensity than the processed laser light.
The failure detection method according to any one of claims 7 to 10.

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