JP6688021B2 - Laser welding monitoring device and laser welding monitoring method - Google Patents

Description

  The present invention relates to a laser welding monitoring device and a laser welding monitoring method capable of performing welding monitoring with high defect detection accuracy.

  In a manufacturing process of an electrode used as an automobile battery or the like, an invention aiming at early detection of welding defects in all products by monitoring a molten state of a work to be welded in real time is disclosed in Patent Document 1 below. Have been described.

  In the detection device of this document, the work is made of a foil-shaped aluminum alloy, and a reflected light condensing unit that condenses the reflected light of the light waves scattered from the welding site and an infrared light concentrator that condenses the infrared light. The light section, each sensor section that extracts reflected light and infrared light of a predetermined wavelength from the light waves collected by each condensing section, converts them into electric signals and sends them to the welding state determination processing section, and the above signals. The welding state determination processing unit 11 monitors the time until the welded part is solidified.

  The welding state discrimination processing unit includes a control / calculation unit for monitoring the detection intensity of reflected light and infrared light for each time, an output unit, and a storage unit. First, detection of reflected light after a predetermined time of 2 ms has elapsed. In the case where the peak value of the intensity is 20 or more, which is a predetermined threshold value, and when the peak value of the detected intensity of infrared light is 0.6 or more, the predetermined threshold value, it is determined as "a clear defect". It is disclosed that when it is less than the threshold value B, it is determined as "hidden defect".

JP2012-006036A

  In the in-situ observation and in-situ monitoring of welding of metallic materials using laser light, the method of monitoring the emission intensity of the entire visible light from the molten pool contains a lot of noise, and it is possible to accurately determine whether defects have occurred. It has been difficult to grasp in the past.

  That is, when noise is generated at any wavelength of visible light, when the emission intensity of the entire visible light is detected as in the conventional case, the noise is taken into the detected value to indicate the occurrence of a defect. The signal component is buried in the noise, making its extraction difficult.

  Further, if only the light emission from the molten pool having a wavelength in the infrared region, for example, a wavelength near 1300 nm is detected, the state of the molten pool can be directly observed, but the detection element for infrared light detection is It is considerably more expensive than the detection element. On the other hand, in the case of detecting visible light, it is possible to detect the emission of a plume (a spout of metal vapor or the like) generated from the molten pool, and the visible light detecting element is relatively inexpensive.

  The present invention has been made in view of the above problems, and an object of the present invention is to enable more reliable welding monitoring at a lower cost with improved defect detection accuracy during laser welding.

  The laser welding monitoring apparatus of the present invention is a laser welding monitoring apparatus for monitoring the welding state of a welding site of welding material to be welded by laser light, in which a welding pool is formed by irradiating the welding material with laser light. In the above, the emission intensity of a specific wavelength in visible light, which is determined in advance corresponding to the welding material, is detected, and the welding state is determined based on the detected emission intensity.

  The laser welding monitoring method of the present invention is a laser welding monitoring method for monitoring the welding state of a welding site of a welding material to be welded by laser light, from a molten pool formed by irradiating the welding material with laser light. In the laser welding monitoring method, the emission intensity of one specific wavelength in visible light, which is predetermined according to the welding material, is detected and the welding state is determined based on the detected emission intensity.

  INDUSTRIAL APPLICABILITY The present invention enables more reliable welding monitoring at a lower cost with improved defect detection accuracy during laser welding. By monitoring the change over time in the emission intensity from the molten pool during laser welding for only specific wavelengths, the emission intensity with less noise is detected, and the emission intensity change due to defects such as spattering of spatters and holes is high. It is possible to detect with accuracy.

It is a figure explaining the composition outline of the laser welding system of this embodiment. (A) is a figure explaining the time change of the detection intensity which detected the light emission intensity from a molten pool over the whole visible light when aluminum was used as a welding material, and (b) is using aluminum as a welding material. When used, it is a figure explaining the time change of the detection intensity which detected the emission intensity from a molten pool about only one specific wavelength (400 nm, but half width 25 nm) of visible light. It is a figure explaining the outline of the experimental device used in order to measure the emission spectrum from the molten pool shown in FIGS. It is a figure explaining a normal welding spot and an abnormal welding spot when performing a simulated laser welding with the composition of Drawing 3 using aluminum as a welding rod, and scanning a welding rod for about 1 second, (a). Shows the whole photograph of the scanning part of the welding material (scanning from the left side to the right of the paper), (b) shows the spectrum of the normal welding state of the welding start part, (c) shows the normal welding state in the middle of the scanning of welding. FIG. 4D is a diagram showing a spectrum of an abnormal welding state in the vicinity of a welding end portion. It is a figure which shows the emission spectrum of the visible light from the molten pool in the state where the normal welding using the aluminum welding material (A1050) is performed. It is a figure which shows the spectrum intensity at the time of scanning the aluminum welding material for about 1 second by changing the spectrum wavelength acquired with a spectroscope using the experimental apparatus of FIG. 3, (a) shows the time-dependent change of the spectrum intensity of 395 nm. (B) shows the change over time of the spectrum intensity of 454 nm, (c) shows the change over time of the spectrum intensity of 470 nm, (d) shows the change over time of the spectrum intensity of 487 nm, (e) shows the change over time of 513 nm. The time-dependent change of spectrum intensity is shown, and (f) shows the time-dependent change of spectrum intensity of 542 nm. (A) compares how much the peak intensity at the time of occurrence of a perforated defect increased with respect to the average value of the peak intensity at the time of normal welding for each of the six wavelength ranges when aluminum was used as the welding material. It is a graph shown, and (b) is a graph which compares and shows a standard error rate about each of six wavelength regions. It is a figure explaining the spectrum characteristic from the molten pool regarding the abnormality which arose during performing a laser welding scan for about 1 second using Fe (two sheets of thickness t = 0.5mm pile) as a welding material. It is a figure explaining the spectrum characteristic from the molten pool regarding the abnormality which arose during performing a laser welding scan for about 1 second using Ti (two sheets of thickness t = 0.5mm pile) as a welding material. It is a figure explaining the spectrum characteristic from the molten pool regarding the abnormality which arose during performing a laser welding scan for about 1 second using SUS304 (two sheets of thickness t = 0.5mm pile) as a welding material.

  Conventionally, in visible light monitoring during laser welding, almost the entire visible light wavelength is monitored and measured. Visible light captures plumes (plasma, metal vapor, etc.) generated mainly during laser welding and is effective for detecting welding defects such as holes in the welding material. However, since visible light has an extremely large fluctuation in the amplitude of the measured waveform, it has been conventionally difficult to distinguish between normal welding and abnormal welding based on visible light.

  As the cause of the amplitude fluctuation of the measured waveform of visible light, the influence of ambient light such as illumination, the wavelength band to be acquired and monitored is too wide, and the waveforms of various spectrums are disturbed to cancel, synergize, etc. It is conceivable that the amplitude of the visible light that is being monitored fluctuates over time.

  It can be understood by visually observing through protective glasses during laser welding, but since the plume during laser welding exhibits a light emission color peculiar to the material, the measurement wavelength of the plume may be limited to a specific wavelength for each welding material. Seems to be preferable.

  FIG. 1 is a diagram for explaining the outline of the configuration of a laser welding system 1000 of this embodiment. The laser welding system 1000 includes a laser device 1100 that generates a laser beam for welding, and a processing head 1300 that focuses the laser beam generated by the laser device 1100 on a welding material 1400 via an optical fiber.

  Visible light generated from the molten pool generated by concentrating the laser light energy in the welding material 1400 is condensed by the visible light condensing sensor unit 1500 and photoelectrically converted. An interference filter (not shown) is provided at the lower end (visible light incident side) of the visible light condensing sensor unit 1500. The interference filter passes only one specific wavelength (substantially having a certain wavelength width) corresponding to the welding material 1400.

  The electric signal output from the visible light condensing sensor unit 1500 is input to the quality determination device 1200 to determine quality of welding. During laser welding, if welding failure (typically, a hole in the welding material 1400) occurs, strong light emission from the molten pool of a specific visible light wavelength corresponding to the material of the welding material 1400 is strong. It was found that

  Utilizing this, the laser welding system 1000 constantly monitors only the intensity of visible light of a specific wavelength corresponding to the material of the welding material 1400, and when the light intensity becomes equal to or higher than a predetermined threshold, welding failure occurs. To judge. That is, the quality determination device 1200 determines that the welding is defective when it detects that the value of the electric signal photoelectrically converted by the visible light condensing sensor unit 1500 becomes equal to or larger than a predetermined threshold value.

  FIG. 2A is a diagram for explaining a change over time in the detected intensity when the emission intensity from the molten pool is detected over the entire visible light when aluminum is used as the welding material 1400, and FIG. It is a figure explaining the time change of the detection intensity which detected the luminescence intensity from a molten pool about only one specific wavelength (400 nm, but half-width 25 nm) of visible light when using aluminum as welding material 1400.

  As can be understood from FIG. 2A, when the emission intensity of the entire visible light (400 nm to 700 nm) is detected, the amplitude of the detected value with respect to the progress of laser welding over time increases. Therefore, in this case, the light emission of the specific wavelength from the molten pool showing the welding failure is buried in the noise, and the failure cannot be detected.

  On the other hand, as can be understood from FIG. 2B, when only a specific wavelength is detected by using the 400 nm transmission interference filter having the half width of 25 nm, the amplitude of the detected value with respect to the progress of laser welding is too large. Absent. For this reason, it becomes possible to clearly distinguish a significantly large detection value around time 0.03 (s). 2 (a) and 2 (b), a welding defect occurs at a time of about 0.03 (s) on the horizontal axis, but in FIG. 2 (b), the welding defect is caused. It is possible to detect the vertical deviation of the detected value.

  It is not clear why the up-and-down fluctuation of the emission intensity is detected when a welding failure occurs at a specific wavelength, but when the welding failure occurs, the molten pool boils or scatters, which causes fluctuations in the molten pool surface. Inferred to be related.

  FIG. 3 is a diagram for explaining the outline of the experimental apparatus used for measuring the emission spectrum from the molten pool shown in FIGS. 4 to 6. In FIG. 3, the irradiation laser output was 800 W, the scanning speed was 20 mm / sec, and the welding material on which two aluminum plates (t = 0.5 mm) were stacked was scanned for about 1 second under laser irradiation.

  Then, the emission spectrum from the molten pool formed in the welding material was measured from the angle of 45 ° through the spectroscope head and the spectroscope. The spectrum measurement result by the measurement system shown in FIG. 3 will be described below with reference to FIGS.

  FIG. 4 is a diagram illustrating normal welding points and abnormal welding points when simulated laser welding is performed with aluminum as a welding material with the configuration of FIG. 3 and the welding material is scanned for about 1 second. . FIG. 4 (a) shows an overall photograph of the scanning location of the welding material (scanning from the left side to the right side of the paper), FIG. 4 (b) shows the spectrum of the normal welding state at the welding start location, and FIG. 4 (c). FIG. 4D is a diagram showing a spectrum in a normal welding state in the middle of the scanning of welding, and FIG. 4D is a diagram showing a spectrum in an abnormal welding state in the vicinity of the welding end portion.

  As can be understood from FIG. 4, the abnormal welding with holes occurs in FIG. 4 (d), but in the abnormal welding with holes, as compared with the normal state in FIGS. 4 (b) and 4 (c), Particularly, a remarkable increase in the spectral intensity is detected from 350 nm to 500 nm. Therefore, by utilizing this phenomenon, the laser welding system 1000 monitors the molten pool at a specific wavelength of 400 nm, for example, when aluminum is used as the welding material 1400, and welds when the detected intensity increases above a threshold value. Judge as defective.

  Further, FIG. 5 is a diagram showing an emission spectrum of visible light from the molten pool in a state where normal welding using the aluminum welding material (A1050) is performed. As shown in FIG. 5, peaks at which the spectral intensity increases are found at six wavelengths of 395 nm, 454 nm, 470 nm, 487 nm, 513 nm, and 542 nm, respectively.

  Then, explain the results of investigating which peak wavelength among the six peaks is used when aluminum is used as the welding material, and the occurrence of welding defects such as perforation can be detected most reliably and stably. It is shown in FIG.

  FIG. 6 is a diagram showing the spectrum intensity when the aluminum welding material is scanned for about 1 second while changing the spectrum wavelength acquired by the spectroscope, using the experimental apparatus of FIG. FIG. 6A shows the temporal change of the spectrum intensity of 395 nm, FIG. 6B shows the temporal change of the spectrum intensity of 454 nm, and FIG. 6C shows the temporal change of the spectrum intensity of 470 nm. Further, FIG. 6D shows a temporal change of the spectrum intensity of 487 nm, FIG. 6E shows a temporal change of the spectrum intensity of 513 nm, and FIG. 6F shows a temporal change of the spectrum intensity of 542 nm.

  As shown in FIG. 6, the spectral intensity increases when a defective weld with a hole occurs (around 0.7 seconds) in any of the six wavelength ranges, but a significant difference is found in the rate of increase depending on the wavelength. . From the above viewpoint, in the case of aluminum welding materials, it is preferable to use around 395 nm, where the spectrum increase is most noticeable, as the optimum wavelength for more clearly distinguishing welding defects such as holes.

  FIG. 7 (a) compares how much the peak intensity at the time of occurrence of a perforated defect increased with respect to the average value of the peak intensity at the time of normal welding for each of the six wavelength bands when aluminum was used as the welding material. Is a graph shown. Further, FIG. 7B is a graph showing the standard error rates for each of the six wavelength bands in comparison. Also from the results shown in FIGS. 7 (a) and 7 (b), when aluminum is used as the welding material, the most suitable welding defect can be detected by detecting the emission intensity using the wavelength region near 395 nm. I understand what I can do.

  Note that FIG. 7B shows the result of calculating the standard error rate by extracting only the spectral intensity at the time of normal welding, and the 395 nm region is the most stable among the calculated six wavelength regions. It can be seen that the spectral intensity is obtained. For this reason, in the wavelength range, the variation in the emission peak intensity during normal welding is relatively small, while the peak intensity increases approximately 110 times when a defect occurs, so that the monitoring is highly reliable. Is possible.

  FIG. 8 is a diagram for explaining the spectral characteristics from the molten pool regarding anomalies that occurred during the execution of laser welding scanning for 1 second using Fe (two sheets having a thickness t = 0.5 mm as a welding material). In FIG. 8, normal laser welding is performed at 0.11 seconds and 0.77 seconds after the start of scanning, but a welding abnormality (perforation) occurs at 0.605 seconds after the start of scanning.

  Comparing the emission spectrum intensities from the molten pools at these three points (at three points in time), the spectral emission intensities increase over almost the entire wavelength range when a hole is formed. Among them, especially, in the vicinity of 590 nm (589.92 nm is shown as a typical example in FIG. 8), the ratio (S / N ratio) of the emission spectrum intensity in the normal state to the emission spectrum intensity in the abnormal state is 4.12. It is remarkably larger than the S / N ratio of other wavelengths.

  Therefore, when Fe (iron) is used as the welding material, a wavelength around 590 nm (between 565 nm and 615 nm) is monitored as a monitor wavelength, and during laser welding, the emission intensity from the molten pool at that wavelength is 3. It is preferable to determine that an abnormality has occurred when the number of times is increased five times or more. Thereby, when Fe is used as the laser welding material, more stable and more reliable laser welding quality determination (that is, detection of welding failure) can be performed.

  Further, FIG. 9 is a diagram for explaining the spectral characteristics from the molten pool regarding an abnormality that occurred during performing a laser welding scan for 1 second using Ti (two sheets having a thickness t = 0.5 mm) as a welding material. In FIG. 9, normal laser welding is performed at 0.11 seconds and 0.935 seconds after the start of scanning, but welding abnormalities (holes) occur at 0.66 seconds after the start of scanning.

  Comparing the emission spectrum intensities from the molten pools at these three points (at three points in time), the spectral emission intensities increase over almost the entire wavelength range when a hole is formed. Among them, in particular, in the vicinity of 770 nm (771.19 nm is shown as a typical example in FIG. 9), the ratio (S / N ratio) between the emission spectrum intensity in the normal state and the emission spectrum intensity in the abnormal state is 3.5. It is remarkably larger than the S / N ratio of other wavelengths.

  Therefore, when Ti is used as the welding material, the wavelength around 770 nm (between 745 nm and 795 nm) is monitored as the monitor wavelength, and during laser welding, the emission intensity from the molten pool at that wavelength is 2.5 times or more. It is preferable to determine that an abnormality has occurred when the number has increased. Accordingly, when Ti is used as the laser welding material, more stable and more reliable laser welding quality determination (that is, detection of welding failure) can be performed.

  Further, FIG. 10 is a diagram for explaining the spectral characteristics from the molten pool regarding an abnormality that occurred during the execution of the laser welding scan for 1 second using SUS304 (two sheets having a thickness t = 0.5 mm) as a welding material. In FIG. 10, normal laser welding is performed at 0.11 seconds and 0.99 seconds after the start of scanning, but welding abnormalities (holes) occur at 0.55 seconds after the start of scanning.

  Comparing the emission spectrum intensities from the molten pools at these three points (at three points in time), the spectral emission intensities increase over almost the entire wavelength range when a hole is formed. Among them, particularly, in the vicinity of 770 nm (in FIG. 10, 769.94 nm is shown as a typical example), the ratio (S / N ratio) between the emission spectrum intensity in the normal state and the emission spectrum intensity in the abnormal state is 2.09. It is remarkably larger than the S / N ratio of other wavelengths.

  Therefore, when SUS304 is used as the welding material, the wavelength around 770 nm (between 745 nm and 795 nm) is monitored as the monitor wavelength, and during laser welding, the emission intensity from the molten pool at that wavelength is more than doubled. When it does, it is preferable to determine that an abnormality has occurred. Accordingly, when SUS304 is used as the laser welding material, more stable and more reliable laser welding quality determination (that is, detection of welding failure) can be performed.

  The laser welding monitoring apparatus of the present invention is a laser welding monitoring apparatus for monitoring the welding state of a welding site of a welding material to be welded by laser light, in which the welding material is melted by irradiation with laser light. The present invention is characterized by detecting the emission intensity of one specific wavelength in visible light, which is predetermined from the pond corresponding to the welding material, and determines the welding state based on the detected emission intensity.

  Therefore, by monitoring a specific wavelength in the visible light region according to the characteristics of the welding material, more stable, reliable and easy in-situ detection of welding defects becomes possible. In addition, since it is possible to detect welding defects quickly while laser welding is in progress, a laser welding monitoring device that can perform post-detection processing such as temporary stop of laser welding and feedback control of laser output quickly and more appropriately. Can be realized.

  Further, the laser welding monitoring apparatus of the present invention is preferably characterized in that the specific one wavelength is one of the peak wavelengths of a plurality of emission spectra from the weld pool of the welding material.

  Corresponding to the welding material used for laser welding, the peak wavelength of the emission spectrum from the molten pool formed by the welding material is a wavelength that reflects the unique characteristics of the welding material. The peak wavelength is considered to be a wavelength that also includes information on welding defects when welding defects such as holes in the welding material occur. By using this wavelength as the monitor wavelength, it is possible to realize a laser welding monitoring apparatus capable of performing more accurate in-situ monitoring of welding progress.

  Further, the laser welding monitoring apparatus of the present invention is further preferably characterized in that the welding material is aluminum or iron or titanium or copper or steel.

  In the above-described embodiment, the case where aluminum, Ti, Fe, and SUS304 are used as the laser welding material (two sheets each having t = 0.5 mm) is described as a typical example, but the present invention is not limited to this. Obvious to the trader.

  It is easily understood by those skilled in the art that the technical idea of the present invention can be applied to copper, various steel materials and the like that may be used as a laser welding material. Even for copper and various steel materials, the emission pool peculiar to the material is observed from the molten pool generated during laser welding. Therefore, by using any one of the wavelength regions of the peak wavelength of the emission spectrum, the laser welding monitoring device can perform stable and reliable welding quality determination.

  The laser welding monitoring apparatus of the present invention is characterized in that when the welding material is aluminum, one specific wavelength is 375 nm to 425 nm.

  When aluminum is used as the welding material, the ratio of the emission intensity between normal welding and abnormal welding is the largest at the peak wavelength of 390 nm as a typical example. Therefore, by performing in-situ monitoring when the laser welding is in progress using the wavelength region, it is possible to provide a laser welding monitoring apparatus that can stably determine the quality of the laser welding. With respect to the peak wavelength of 390 nm, it is considered that the emission intensity in the wavelength region of about 365 nm to 415 nm should be substantially detected in consideration of the half width and the like. In this case, the laser welding monitoring apparatus may monitor the entire wavelength range of 365 nm to 415 nm as a specific wavelength, or may monitor any single wavelength in the range of 365 nm to 415 nm as a specific wavelength. Good.

  Further, in the laser welding monitoring apparatus of the present invention, more preferably, the specific wavelength is 565 nm to 615 nm when the welding material is iron, and the specific wavelength is 745 nm to 745 nm when the welding material is SUS. When the welding material is titanium, the specific wavelength is 745 nm to 795 nm.

  When iron, SUS304, and titanium are used as the welding materials, the emission intensity ratio between normal welding and abnormal welding is maximized at the peak wavelengths of 590 nm, 770 nm, and 770 nm, respectively.

  Therefore, by performing in-situ monitoring when the laser welding is in progress using the wavelength region, it is possible to provide a laser welding monitoring apparatus that can stably determine the quality of the laser welding. Regarding the peak wavelengths of 590 nm, 770 nm, and 770 nm, it is considered that the emission intensities in the wavelength regions of about 565 nm to 615 nm, 745 nm to 795 nm, and 745 nm to 795 nm may be substantially detected, considering the half width and the like. Be done.

  In this case, the laser welding monitoring device may monitor the entire wavelength region of 565 nm to 615 nm, 745 nm to 795 nm, 745 nm to 795 nm as a specific wavelength, or 565 nm to 615 nm, 745 nm to 795 nm, 745 nm to 745 nm. Any single wavelength in the range of 795 nm may be monitored as a specific wavelength.

  Further, the laser welding monitoring apparatus of the present invention is characterized in that it is a fiber laser whose laser light is 1070 nm to 1100 nm.

  As a result, laser welding using a fiber laser having a laser light wavelength of 1070 nm to 1100 nm, which is widely used as a laser welding device, can be monitored and welding defects can be appropriately detected.

  Further, regarding the welding site of the welding material to be welded by laser light, the laser welding monitoring method of the present invention for monitoring the welding state is a welding material from a molten pool formed by irradiating the welding material with laser light. It is characterized by detecting the emission intensity of one specific wavelength in visible light, which is previously determined in accordance with, and determining the welding state based on the detected emission intensity.

  Therefore, by monitoring a specific wavelength in the visible light region according to the characteristics of the welding material, more stable, reliable and easy in-situ detection of welding defects becomes possible. In addition, because it is possible to detect welding defects promptly while laser welding is in progress, a laser welding monitoring method that can perform post-detection processing such as temporary stop of laser welding and feedback control of laser output quickly and more appropriately. Can be realized.

  Further, the laser welding monitoring method of the present invention is preferably characterized in that the specific one wavelength is one of the peak wavelengths of a plurality of emission spectra from the weld pool of the welding material.

  Corresponding to the welding material used for laser welding, the peak wavelength of the emission spectrum from the molten pool formed by the welding material is a wavelength that reflects the unique characteristics of the welding material. The peak wavelength is considered to be a wavelength that also includes information on welding defects when welding defects such as holes in the welding material occur. By using this wavelength as the monitor wavelength, it is possible to realize a laser welding monitoring method capable of performing more accurate in-situ monitoring of welding progress.

  Further, the laser welding monitoring method of the present invention is characterized in that the welding material is aluminum, iron, titanium, copper, or steel.

  In the above-described embodiment, the case where aluminum, Ti, Fe, and SUS304 are used as the laser welding material (two sheets each having t = 0.5 mm) is described as a typical example, but the present invention is not limited to this. Obvious to the trader.

  It is easily understood by those skilled in the art that the technical idea of the present invention can be applied to copper, various steel materials and the like that may be used as a laser welding material. Even for copper and various steel materials, the emission pool peculiar to the material is observed from the molten pool generated during laser welding. Therefore, by using any one of the wavelength regions of the peak wavelength of the emission spectrum, the laser welding monitoring method can perform stable and reliable welding quality determination.

  Further, the laser welding monitoring method of the present invention is characterized in that the specific wavelength is 375 nm to 425 nm when the welding material is aluminum.

  When aluminum is used as the welding material, the ratio of the emission intensity between normal welding and abnormal welding is the largest at the peak wavelength of 390 nm as a typical example. Therefore, by performing in-situ monitoring while the laser welding is in progress using the wavelength region, it is possible to provide a laser welding monitoring method capable of stably determining the quality of the laser welding. With respect to the peak wavelength of 390 nm, it is considered that the emission intensity in the wavelength region of about 365 nm to 415 nm should be substantially detected in consideration of the half width and the like. In this case, the present laser welding monitoring method may monitor the entire wavelength region of 365 nm to 415 nm as a specific wavelength, or may monitor any single wavelength in the range of 365 nm to 415 nm as a specific wavelength. Good.

  Further, in the laser welding monitoring method of the present invention, when the welding material is iron, the specific wavelength is 565 nm to 615 nm, and when the welding material is SUS, the specific wavelength is 745 nm to 795 nm. When the welding material is titanium, one specific wavelength is 745 nm to 795 nm.

  When iron, SUS304, and titanium are used as the welding materials, the emission intensity ratio between normal welding and abnormal welding is maximized at the peak wavelengths of 590 nm, 770 nm, and 770 nm, respectively. Therefore, by performing in-situ monitoring while the laser welding is in progress using the wavelength region, it is possible to provide a laser welding monitoring method capable of stably determining the quality of the laser welding.

  Regarding the peak wavelengths of 590 nm, 770 nm, and 770 nm, it is considered that the emission intensities in the wavelength regions of about 565 nm to 615 nm, 745 nm to 795 nm, and 745 nm to 795 nm may be substantially detected, considering the half width and the like. Be done.

  In this case, the laser welding monitoring device may monitor the entire wavelength region of 565 nm to 615 nm, 745 nm to 795 nm, 745 nm to 795 nm as a specific wavelength, or 565 nm to 615 nm, 745 nm to 795 nm, 745 nm to 745 nm. Any single wavelength in the range of 795 nm may be monitored as a specific wavelength.

  Further, the laser welding monitoring method of the present invention is more preferably characterized by using a fiber laser having a laser beam of 1070 nm to 1100 nm.

  As a result, laser welding using a fiber laser having a laser light wavelength of 1070 nm to 1100 nm, which is widely used as a laser welding device, can be monitored and welding defects can be appropriately detected.

  The laser welding apparatus and the laser welding monitoring method of the present invention are not limited to the configurations and methods described in the above description of the present embodiment, and may be freely changed within the scope of the present invention and within the scope obvious to those skilled in the art. It is possible to modify, arrange and arrange. Further, it is possible to use it by appropriately combining it with a conventionally known device configuration and method, and by appropriately changing the order.

  INDUSTRIAL APPLICABILITY The present invention can be widely applied to a laser light welding monitoring system for various electronic components such as capacitors.

  Laser welding system 1100 Laser device 1200 Quality determination device 1300 Processing head 1400 Welding material 1500 Visible light condensing sensor unit

Claims (14)

Regarding the welding site of the welding material to be welded by laser light, in the laser welding monitoring device that monitors the welding state,
From the molten pool formed on the front side by irradiating the welding material with the laser beam, the emission intensity of a specific one wavelength in visible light, which is determined in advance corresponding to the welding material, is detected. A laser welding monitoring apparatus, wherein a welding state is determined based on the emission intensity. The laser welding monitoring device according to claim 1,
The said one specific wavelength is one of the peak wavelengths of the several emission spectrum from the said molten pool of the said welding material. The laser welding monitoring apparatus characterized by the above-mentioned. The laser welding monitoring apparatus according to claim 1 or 2,
The laser welding monitoring device is characterized in that the welding material is aluminum, iron, titanium, copper, or steel. The laser welding monitoring apparatus according to claim 3,
When the welding material is aluminum, the specific wavelength is 375 nm to 425 nm . The laser welding monitoring apparatus according to claim 3,
When the welding material is iron, the specific wavelength is 565 nm to 615 nm, when the welding material is SUS, the specific wavelength is 745 nm to 795 nm, and the specific welding wavelength is titanium. In this case, the specific wavelength is 745 nm to 795 nm. The laser welding monitoring device according to any one of claims 1 to 5,
The laser beam is a fiber laser having a wavelength of 1070 nm to 1100 nm. Regarding the welding site of the welding material to be welded with laser light, in the laser welding monitoring method for monitoring the welding state,
From the molten pool formed on the front side by irradiating the welding material with the laser beam, the emission intensity of a specific one wavelength in visible light, which is determined in advance corresponding to the welding material, is detected. A laser welding monitoring method, comprising: determining a welding state based on the emission intensity. The laser welding monitoring method according to claim 7,
The laser welding monitoring method, wherein the one specific wavelength is one of peak wavelengths of a plurality of emission spectra from the molten pool of the welding material. The laser welding monitoring method according to claim 7 or claim 8,
The laser welding monitoring method, wherein the welding material is aluminum, iron, titanium, copper, or steel. The laser welding monitoring method according to claim 9,
When the welding material is aluminum, the specific wavelength is 375 nm to 425 nm. The laser welding monitoring method according to claim 9,
When the welding material is iron, the specific wavelength is 565 nm to 615 nm, when the welding material is SUS, the specific wavelength is 745 nm to 795 nm, and the specific welding wavelength is titanium. In this case, the specific wavelength is 745 nm to 795 nm. The laser welding monitoring method according to any one of claims 7 to 11,
The laser welding monitoring method is characterized in that the laser light is a fiber laser of 1070 nm to 1100 nm. The laser welding monitoring device according to any one of claims 1 to 6,
The detection of the emission intensity of the specific one wavelength is performed through a transmission interference filter having a half width of 25 nm.
A laser welding monitoring device characterized in that The laser welding monitoring method according to any one of claims 7 to 12,
The detection of the emission intensity of the specific one wavelength is performed through a transmission interference filter having a half width of 25 nm.
A laser welding monitoring method characterized by the above.