JP2011167697A - Method and device for determining laser welding quality - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device for determining laser welding quality which enable false determination of defective welding to be suppressed and enable image processing loads to be suppressed. <P>SOLUTION: The method and the device for determining laser welding quality are provided. The method determines welding quality of a weld part (b) when the predetermined laser welding apparatus irradiates the weld part with laser beam (La) and welds superposed plate-like members (P1, P1) to be welded, during the welding. The method includes a first determination step of determining presence/absence of defective weld of the weld part based on the intensity of the laser beam generated from the weld part when irradiating the weld part of a member to be welded with laser beam, and a second determination step of determining the weld state of the weld part by processing by a predetermined image forming apparatus, the beam image of the weld part which is determined to be defective only when the weld of the weld part is determined to be defective by the first determination step. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a laser welding quality determination method and an apparatus therefor, and in particular, the welding quality of a welded portion when welding plate-like welded members that are overlapped by irradiating laser light with a predetermined laser welding apparatus. The present invention relates to a laser welding quality judgment method and a laser welding quality judgment device.

  2. Description of the Related Art Conventionally, for example, in a roof or a pillar of an automobile body, it is known that plates are joined to each other using spot welding in which electrodes are pressed from both sides with electrodes. In such spot welding, poor welding occurs due to a shunt due to contact with the plate due to bending of the spot welding shank, or in the case of an automobile, a plurality of welding locations must be provided to increase the rigidity of the vehicle body. There was a problem.

  On the other hand, in the case of laser welding, laser light is applied from one side of a plate, and continuous welding (welding in a linear shape) is also possible. However, in laser welding, unlike spot welding, the plates are not pressed from both sides, so it is difficult to manage the gap between the plates (plate gap), and welding defects are more likely to occur than spot welding. That is, there has been a problem that defects (such as blow-up, melt-down, perforation, underfill, and bit generation) occur in the weld.

Therefore, it becomes necessary to determine the quality of the laser welded part, or it is necessary to manage the plate gap.
Therefore, conventionally, for example, in Patent Document 1, a plasma light image generated in a keyhole portion of an object to be welded during laser welding is captured by a high-speed camera, and the obtained image is immediately and continuously image processed. Discloses a laser welding quality inspection method and apparatus for determining the quality of welding quality by obtaining the tilt angle of a plasma light image.

  Further, Patent Document 2 discloses that an abnormality occurs in a laser welded portion due to a gap between the plates, and also analyzes the variation of the frequency component of light from the laser welded portion to determine the quality of the laser welded portion. An apparatus and method for determining the quality of a laser welding part to be determined are disclosed.

JP2004-0666267 JP 2006-159242 A

  However, the method and apparatus of Patent Document 1 perform welding immediately after image processing of plasma light from the keyhole portion, and the load on the processing capability of the processing apparatus becomes very heavy. Moreover, since a high-speed camera is used or a computer with a high processing apparatus is used, the cost becomes high.

  Here, in laser welding, a so-called so-called welding failure occurs, and a defect referred to as a hole may eventually occur. However, the melted metal (the metal plate that is the object to be welded melted by the laser beam) depends on the surface tension of the still melted metal depending on the gap between the plates and the inclination between the plates. There is a case where a phenomenon occurs in which a holed portion of a welded portion flows back to be filled, and as a result, a holed defect does not occur. Even in such a case, the welding strength is maintained.

  With respect to such a phenomenon, the method and apparatus of Patent Document 2 described above determines the quality of the welded part only by the light generated from the welded part irradiated with the laser beam. Even when no perforated defect occurs, it is erroneously determined to be a defect (welding failure erroneous determination).

  Moreover, in the method and apparatus of patent document 2, using a high-speed camera, the plasma light from a keyhole part is image-processed immediately, and since the welding is image-processed, it is processed. There is a high possibility of erroneous determination of poor welding as described above.

The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a laser welding quality determination method and a laser welding quality determination apparatus that can suppress an image processing load.
The present invention has been made to solve the above-described problems of the prior art, and provides a laser welding quality determination method and a laser welding quality determination apparatus that can suppress erroneous determination of welding failure and suppress image processing load. The purpose is to provide.

  In order to achieve the above object, the present invention determines the welding quality of a welded portion during welding when plate-like members to be welded that are overlapped by irradiating laser light with a predetermined laser welding apparatus are welded together. A first determination step for determining the presence or absence of welding defects in the welded portion based on the intensity of light generated from the welded portion when the welded portion of the member to be welded is irradiated with laser light; Only when it is determined that the welding of the welded portion is defective in one determination step, the optical image of the welded portion determined to be defective in welding is subjected to image processing by a predetermined image processing apparatus, and the welded portion of the welded portion is welded. And a second determination step for determining the state.

  In the present invention configured as described above, only when the welding of the welded portion of the overlapped plate-like welded members during welding is determined to be defective in the first determination step, the second determination step. The optical image of the welded part determined to be defective in welding is subjected to image processing by a predetermined image processing device, and the welding state of the welded part is determined, so that the image processing load on the predetermined image processing device is suppressed. I can do it.

In the present invention, preferably, the second determination step is executed after a predetermined time from the first determination step.
In the present invention configured as described above, the welding state of the welded portion is determined in the second determination step after a predetermined time from the detection of the welding failure in the first determination step. If a phenomenon such as backfilling occurs during the predetermined time in the welded portion that is determined as poor welding, it is determined in the second determination step that there is no defect such as a hole in the welding state. As a result, erroneous determination of poor welding can be suppressed. Moreover, since the 2nd determination step which performs an image process is performed after the predetermined time from a 1st determination step, the image capture of the welding part determined to be a welding defect can be performed easily. Further, since the second determination step for determining the welding state by image processing is executed only when it is determined by the first determination step that the welding of the welded portion is defective, the image processing load by the predetermined image processing apparatus is also increased. It is suppressed.

  In order to achieve the above object, the present invention comprises a laser beam irradiating means for irradiating laser beams to the welded portions of the overlapped plate-like welded members and welding the plate-like welded members to each other. Light detection means for detecting light generated from a welded portion irradiated with laser light by the laser light irradiation means, and welding failure of the welded portion based on the intensity of light generated from the welded portion detected by the light detection means A first determination unit that determines the presence or absence of the image, and an image capturing unit that is provided on the rear side of the laser beam irradiation unit with respect to the welding progress direction of the member to be welded, and that captures an optical image of light generated from the welded portion, A second image processing determining unit that analyzes the optical image of the welded portion captured by the image capturing unit and determines a welding state of the welded portion based on the analyzed image analysis result; and a first determining unit Due to the weld failure, Only when it is determined that the welded part is determined to be defective in welding, the optical image of the welded part captured by the image capturing means is subjected to image analysis, and based on the analyzed image analysis result. And control means for controlling the second image processing judging means so as to judge the welding state of the welded portion.

  In the present invention configured as described above, the presence or absence of welding defects in the welded portion is determined based on the intensity of light generated from the welded portion of the overlapped plate-like welded members welded by the laser beam irradiation means. The first determination means for determining first determines whether or not there is a welding defect in the welded portion, and the control means is poor in welding only when the first determining means determines that the welded portion is defective in welding. Second image processing determination so as to analyze the optical image of the welded portion captured by the image capturing means and determine the welded state of the welded portion based on the analyzed image analysis result. Since the means is controlled, the image processing load by the second image processing determination means can be suppressed.

In the present invention, it is preferable that the control unit captures the welded portion determined to be poor welded by the image capturing unit after a predetermined time when the welded portion is determined to be poorly welded by the first determining unit. The second image processing determining means is controlled so as to analyze the optical image of the welded portion and determine the welding state of the welded portion based on the analyzed image analysis result.
In the present invention configured as described above, the welding state of the welded portion by the second image processing determining unit is determined for the welded portion determined to be welded after a predetermined time from the detection of the welding failure by the first determining unit. Since the determination is performed, for example, when a phenomenon such as backfilling occurs in a predetermined time in a welded portion that is determined to be defective due to dropout in the first determination unit, the second image processing determination unit performs welding. As a state, it is determined that a defect such as a hole is not generated, and as a result, erroneous determination of welding failure can be suppressed. In addition, since the second image processing determination unit performs image processing after a predetermined time from the first determination unit, when capturing the light image of the light generated from the welded portion by the image capturing unit at any time during welding, or It is possible to appropriately execute image processing of the welded portion determined to be poor in welding, including the case where the optical image is captured only when the welded portion is determined to be poorly welded by the first determining means. . Furthermore, since the control means controls the second image processing determination means to be executed only when the first determination means determines that the welding of the welded portion is defective, the image processing load caused by the second image processing determination means Is also suppressed.

  According to the laser welding quality determination method and the laser welding quality determination apparatus according to the present invention, it is possible to determine the quality of a welded part of laser welding while suppressing an image processing load. Further, it is possible to determine the quality of the welded part of laser welding while suppressing erroneous determination of welding failure and suppressing the image processing load.

It is the schematic which shows schematic structure of the laser welding quality determination apparatus by embodiment of this invention. It is a conceptual diagram which visualizes and shows both the fusion | melting state of the to-be-welded object irradiated with the laser beam, and the light which generate | occur | produces in the welding part. It is a flowchart which shows an example of the process by the laser welding quality determination method performed by the laser welding quality determination apparatus by embodiment of this invention. It is the schematic corresponding to FIG.1 and FIG.2 which shows the state of the to-be-welded part in the welding quality determination in laser welding, and the welding quality determination condition. It is a figure which shows the welding state of the welding part of the plate-shaped to-be-welded member overlapped, respectively. It is the top view which looked at the molten pool from the direction which irradiates a laser beam, The FIG. 6 (a) shows the state of the welding part in the time of irradiating a laser beam, FIG.6 (b), (c) is FIG. FIG. 4 is a diagram illustrating a state after a predetermined time from a certain point in time.

Hereinafter, a laser welding quality determination method and a laser welding quality determination apparatus according to embodiments of the present invention will be described with reference to the accompanying drawings.
First, a laser welding quality determination apparatus according to an embodiment of the present invention will be described with reference to FIG.
FIG. 1 is a schematic diagram showing a schematic configuration of a laser welding quality determination apparatus according to an embodiment of the present invention.
First, as shown in FIG. 1, a laser welding quality determination apparatus 1 according to an embodiment of the present invention is configured integrally with a laser welding machine 2. The laser welding machine 2 includes a laser oscillator 4, a transmission fiber 6 that transmits the laser light La output from the laser oscillator 4, and a collimator lens 8 that converts the laser light La spreading from the transmission fiber 6 at a predetermined angle into parallel light. And a focus lens 10 that condenses the laser light that has become parallel light at the welding point b of the workpiece, and the lenses 8 and 10 are provided in the processing head 12.

  In the present embodiment, the workpieces are assumed to be galvanized steel plates P1 and P2 used for automobile roofs, doors, etc., and these are overlapped and irradiated with the laser beam La by the laser welding machine 2 to be welded to each other. It shall be.

  Further, a half mirror 14 that is inclined obliquely so as to reflect only the light Lb generated at the welding point b to the side is provided in the processing head 12 of the laser welding machine 2. The light Lb will be described later with reference to FIG.

  The laser welding quality determination apparatus 1 according to the present embodiment has a photodetector 16 that detects the light Lb reflected by the half mirror 14. The light detector 16 determines whether or not there is a welding defect at the welding point b based on the detected intensity of the light Lb.

  The laser welding quality determination apparatus 1 according to the present embodiment has an image processing device 18 attached to the processing head 12, and a weld pool, which will be described later, is provided on the workpiece side of the image processing device 18. A camera 20 for capturing an optical image of the light generated from is attached. The image processing device 18 performs image analysis on the optical image captured by the camera 20, and based on the analyzed image analysis result, the welding state of the welded portion (whether there is a defect, what type of welding it is, Or not).

  In addition, the laser welding quality determination apparatus 1 according to the present embodiment includes a control device 22 connected to the photodetector 16 and the image processing device 18. As will be described later, the control device 22 controls the image processing device 18 based on the determination result of the presence or absence of welding failure of the welding point b by the light Lb detected by the light detector 16. The control device 22 also serves as a control device for the laser welding machine 2 and controls on / off of the laser oscillator 4.

  In addition, you may make it determine the presence or absence of the welding defect of the welding point b by this control apparatus 22 based on the intensity | strength of the light Lb detected by the photodetector 16. FIG. Further, the control device 22 may determine the welding state of the weld based on the image analysis result analyzed by the image processing device 18. The control device 22 is shown as a separate unit in FIG. 1, but may be incorporated in the image processing device 20, the photodetector 16, the laser welding machine 2, or the like.

  Next, with reference to FIG. 2, the molten state of the workpiece to be irradiated with the laser beam La and the light Lb generated at the welding point b will be described. FIG. 2 is a conceptual diagram showing the melted state of the work piece irradiated with the laser light and the light generated at the welded portion, which are visualized for explanation.

First, the molten state of the work piece irradiated with laser light will be described.
As shown in FIG. 2, the workpiece P is heated, melted, or evaporated (boiling) by a laser beam La (not shown) focused on the welding point b. At the welding point b, a hole called a keyhole is formed by the vapor pressure due to intense boiling. In the present embodiment, in the laser welding process, the machining head 12 (laser welding quality determination apparatus 1 as a whole) shown in FIG. 1 moves relatively from the right side to the left side in FIG. Laser welding is performed, and as shown in FIG. 2, a molten pool in which molten metal accumulates is formed behind the welding direction. In this molten pool, the molten metal is solidified while gradually radiating heat. In the process of solidification of the molten metal in the molten pool, even if a defect such as “melting off” or “hole formation” (see FIG. 5) occurs at the welding point b, the plate gap (laser welding) Depending on the surface tension of the molten metal, depending on the state of the gap between the galvanized steel plates P1 and P2) and the inclination between the plates, the “melted out” and “perforated” of the welded portion again. In other words, a so-called “backfilling” phenomenon occurs in which the portion of the film flows backfilling, and as a result, defects such as “melting off” and “perforation” may not occur. The galvanized steel plates P1 and P2 may be laser-welded so as to move relative to the galvanized steel plates P1 and P2. In this case, the molten state is the same as the state shown in FIG.

Next, the light generated at the weld will be described.
As shown in FIG. 2, the light generated in the welded part is mainly generated by the light reflected by the laser beam itself that has not been absorbed by the workpiece (wavelength near 1060 nm) and the evaporation of the metal from the keyhole. Plasma light (wavelength 1100 nm or more) and infrared rays (600 nm or less) generated by radiation of molten metal heat in the molten pool.
In the present embodiment, the light detector 16 separates the light Lb using a spectral filter (not shown) that splits the light into a specific wavelength region, and detects the reflected light of the laser and the plasma light. .

Next, the laser welding quality determination method according to the embodiment of the present invention executed by the laser welding quality apparatus according to the embodiment of the present invention will be described with reference to FIGS.
FIG. 3 is a flowchart showing an example of processing by the laser welding quality determination method executed by the laser welding quality determination apparatus according to the embodiment of the present invention, and FIG. 4 shows the parts to be welded during welding quality determination during laser welding. FIG. 5A to FIG. 5C are schematic views corresponding to FIGS. 1 and 2 showing the state of welding and the welding quality judgment status, and FIGS. 5A to 5C show the welding state of the welded portion of the overlapped plate-like welded members. FIG. 6 is a plan view of the molten pool as viewed from above, which is the direction in which the laser beam is irradiated, and FIG. FIGS. 6B and 6C are views showing a state after a predetermined time from a certain point in time, respectively. In FIG. 3, S indicates each step.

  First, as shown in FIG. 3, in S1, the laser oscillator 4 is turned on by the control device 22 shown in FIG. 1, and laser welding by the laser welding machine 2 is started. 1 is moved in the direction indicated by arrow A in FIG. 4 (welding progress direction), and continuous welding (welding in a line) of the galvanized steel sheets P1 and P2 as the parts to be welded is started.

Next, it progresses to S2, and the photodetector 16 shown in FIG. 1 detects the intensity | strength of the light Lb generate | occur | produced from a welding part, when the laser beam La is irradiated to the welding part of the to-be-welded members P1 and P2.
Next, it progresses to S3 and the photodetector 16 determines the presence or absence of the welding defect of the welding point b based on the intensity | strength of the light Lb detected by S2. In S3, for example, whether there is a defect such as a so-called “melt-off” state as shown in FIG. 5A or a so-called “perforated” state as shown in FIG. 5B. To detect. Other defects include blow-up, underfill, and bit generation.

  If no defect is detected in S3, it is determined that laser welding has been successfully performed, and the process proceeds to S4. After this S4, in the present embodiment, the process returns to S2.

If a defect is detected in S3, the process proceeds to S5.
Here, when a defect is detected, for example, as shown in FIG. 6 (a), the welding point b of the welded portion is melted down when viewed from above (as shown in FIG. 5 (a)). It can be visually seen that there is a hole (a state as shown in FIG. 5B). As described above, even if a defect such as “burn-out” or “perforation” occurs at the weld point b, the molten metal solidifies in the molten pool depending on the gap between the plates and the inclination between the plates. In the process, the so-called “backfill” phenomenon occurs in which the “melted” or “holed” portion of the weld flows again due to the surface tension of the molten metal. As a result, defects such as “burn-out” and “perforation” may not occur.

  Therefore, in the present embodiment, the fact that laser welding is continuous welding is used, that is, the fact that the entire laser welding quality determination apparatus 1 is moved in the direction of arrow A is shown in FIGS. As shown in FIG. 4, when the image processing apparatus 18 and the camera 20 arrive after a predetermined time just above the welding point b at a certain time when it is determined that a defect has occurred (in FIG. The image processing device 18, the camera 20, and the molten pool are indicated by phantom lines, and the welding point b after a predetermined time in Fig. 6 is a welding point b 'in Fig. 6 (b) and welding in Fig. 6 (c). Point b ″), whether or not a “backfill” phenomenon occurs at the weld point b ′ (or weld point b ″), and as a result, defects such as “burn-out” and “hole formation” are eliminated. The determination is made by image processing by the image processing device 18. Then, the image processing device 18 and the camera 20 are integrally attached to the laser welding machine 2 so as to be able to do so. In addition, after a predetermined time, the welding point b is a part of the molten pool.

  Specifically, in the present embodiment, the control device 22 detects the camera 20 and the image processing from the time when the defect is detected in S3, for a predetermined time from the time when the defect is detected in S3, that is, from the time of determination in S3. The device 18 counts the time until it comes directly above the weld point b where the defect is detected. The predetermined time can be calculated from the relative mounting positions of the camera 20 and the image processing device 18 with respect to the laser welding machine 2 and the moving speed of the device 1.

  Then, after a predetermined time, in S5, the optical image of the welding point b ′ (or welding point b ″) is captured by the camera 20, and in S6, the optical image captured in S5 is captured by the image processing device 18 in the image processing device 18. Image analysis.

  Next, in S7, based on the image analysis result analyzed in S6, the welding state of the welding point b ′ (or the welding point b ″) (presence / absence of a defect, what kind of welding is used, whether the welding is defective) Or the like).

  In S7, for example, as shown in FIGS. 5C and 6B, if there is a backfilling phenomenon and the defect has disappeared, it is determined that there is no defect, and the process proceeds to S4. After S4, it progresses to S2 and repeats the process mentioned above.

  On the other hand, in S7, for example, as shown in FIG. 6B, if the backfill phenomenon does not occur or is not sufficient, it is determined that there is a defect, and the process proceeds to S8. In S8, a warning or the like is issued to a predetermined worker or the like, assuming that a welding failure has occurred.

  These S5 to S7 are controlled by the control device 22. Note that the predetermined time count and the processing of S5 to S7 may be executed by the image processing apparatus 18 itself. Note that the image capture processing by the camera 20 in S5 does not place a large processing burden on the image processing apparatus 18, so that it is always performed during the laser welding process, and defects are detected in S3 only by the image processing in S6. It may be executed only when That is, the process of S5 may be executed between S1 and S2, or between S2 and S3.

  Next, effects of the laser welding quality determination device and the laser welding quality determination method according to the embodiment of the present invention will be described.

First, the operation and effect of the laser welding quality determination apparatus 1 according to the embodiment of the present invention will be described.
The laser welding quality determination apparatus 1 according to the embodiment of the present invention is adapted to the intensity of the light Lb generated from the welded portions (welding points b) of the overlapped plate-like galvanized steel plates P1 and P2 welded by the laser welding machine 2. Based on the light detector 16 or the control device 22 that determines the presence or absence of welding defects in the welded portion, first, the presence or absence of welding defects in the welded portion is determined, and the image processing device 18 controls the light detector 16 or the control. Only when it is determined by the device 22 that the welded portion is poorly welded, the optical image of the welded portion (welded points b ′, b ″) captured by the camera 20 is subjected to image analysis, and the analyzed image analysis result is obtained. Since the welding state of the welded portions (welding points b ′ and b ″) is determined based on the image processing load on the image processing device 18 can be suppressed.

  Moreover, the laser welding quality determination apparatus 1 according to the embodiment of the present invention uses the camera 20 only when the welded portion (welding point b) is determined to be poorly welded by the light detector 16 or the control device 22. Since the light image of the light generated from the welded portion (welding points b ′, b ″) determined to be is captured, the necessary minimum image capturing can be performed.

  Further, the laser welding quality determination device 1 according to the embodiment of the present invention uses the image processing device 18 after a predetermined time when the welded portion (welding point b) is determined to be poorly welded by the light detector 16 or the control device 22. Since the welding state of the welded portion (welding points b ′, b ″) is determined based on the analyzed image analysis result, for example, the welded portion (welded point b) determined as a defective weld by the first determination means. However, if a phenomenon such as backfilling occurs during the predetermined time, the image processing apparatus 18 determines that a defect such as a hole has not occurred as a welding state, and as a result, erroneous welding failure determination is performed. In addition, since the image processing device 18 performs image processing after a predetermined time from the determination point of welding failure by the light detector 16 or the control device 22, the welded portions (welding points b ′, b ) When taking the light image of the light generated by the camera 20 during welding, or only when it is determined that the weld (weld point b) is poorly welded (weld points b ′, b). The image processing of the welded portion (welded points b ′, b ″) determined to have poor welding can be appropriately executed, including the case where the optical image of “)” is captured. Furthermore, the control means 22 controls the image processing to be executed by the image processing device 18 only when it is determined that the welding of the welded portion (welding point b) is defective. Is suppressed.

Next, the effect of the laser welding quality determination method according to the embodiment of the present invention will be described.
In the laser welding quality determination method according to the embodiment of the present invention, the welding quality of the welded portion (welding point b) when the galvanized steel plates P1 and P2 superimposed by irradiating the laser beam La with the laser welding machine 2 are welded to each other. The intensity of the light generated from the welded portion when the welded portion of the galvanized steel plates P1 and P2 (hereinafter referred to as the welded member) is irradiated with laser light. The determination step S3 (see FIG. 3) for determining the presence or absence of welding failure of the welded portion (welding point b) based on the above, and only when it is determined that the welding of the welded portion is defective by this determination step S3 Determination step of determining the welding state of the welded portion by performing image processing on the optical image of the welded portion (welding points b ′, b ″) determined to be poor welding by the image processing device 18 (S6 in FIG. 3). (S7) Accordingly, the second determination step (S6, S7) is performed only when it is determined in the first determination step (S3) that the weld of the welded portion of the overlapped plate-like welded members during welding is defective. ), The image processing device 18 performs image processing on the optical image of the welded portion determined to be defective in welding and determines the welded state of the welded portion, thereby suppressing the image processing load on the image processing device 18. I can do it.

  Further, in the laser welding quality determination method according to the embodiment of the present invention, the determination step according to S6 and S7 described above is executed after a predetermined time from the determination step according to S3 described above. When a phenomenon such as backfilling occurs in the welded portion (welding point b) determined to be poor in welding during the predetermined time, in the determination step in S6 and S7, a defect such as a hole is present as a welding state. It is determined that it has not occurred, and as a result, erroneous determination of poor welding can be suppressed. In addition, since the determination steps S6 and S7 that perform image processing are executed after a predetermined time from the determination step S3, the image capturing of the welded portion (welding points b ′ and b ″) determined to have poor welding is performed. Further, the determination step by S6 and S7 for determining the welding state by image processing is performed only when the welding of the welded portion (weld point b) is determined to be defective by the determination step by S3. Since it is executed, the image processing load on the image processing device 18 is suppressed.

  As described above, according to the laser welding quality determination method and the laser welding quality determination device according to the embodiment of the present invention, it is possible to determine the quality of a welded portion of laser welding while suppressing erroneous determination of welding failure and suppressing image processing load. I can do it.

DESCRIPTION OF SYMBOLS 1 Laser welding quality determination apparatus 2 Laser welding machine 8 Collimating lens 10 Focus lens 12 Processing head 14 Half mirror 16 Photo detector 18 Image processing apparatus 20 Camera 22 Control apparatus b Welding point La Laser light Lb Light Lb generated at welding point b
P1, P2 Galvanized steel sheet

Claims (4)

A method for determining during welding the weld quality of a welded portion when welding plate-like members to be welded that are overlapped by irradiating laser light with a predetermined laser welding apparatus,
A first determination step of determining the presence or absence of welding failure of the welded portion based on the intensity of light generated from the welded portion when the welded portion of the welded member is irradiated with laser light;
Only when it is determined that the welding of the welded portion is defective in the first determination step, the optical image of the welded portion determined to be defective in welding is subjected to image processing by a predetermined image processing device, and the welded portion is processed. And a second determination step of determining the welding state of the laser welding quality determination method.   The laser welding quality determination method according to claim 1, wherein the second determination step is executed after a predetermined time from the first determination step. Laser light irradiation means for irradiating the welded portions of the overlapped plate-like welded members with laser light to weld the plate-like welded members to each other;
A light detection means for detecting light generated from the welded portion irradiated with the laser light by the laser light irradiation means;
First determination means for determining the presence or absence of welding defects in the weld based on the intensity of light generated from the weld detected by the light detection means;
An image capturing unit that is provided on the rear side of the laser beam irradiation unit with respect to the welding progress direction of the member to be welded, and that captures an optical image of light generated from the weld;
Image analysis of the optical image of the welded portion captured by the image capturing means, and second image processing determining means for determining the welding state of the welded portion based on the analyzed image analysis result;
Only when it is determined by the first determination means that the welded portion is defective in welding, the optical image of the welded portion acquired by the image capturing means is analyzed for the welded portion determined as defective in welding. And a control means for controlling the second image processing determination means so as to determine the welding state of the weld based on the analyzed image analysis result.   The control means is configured such that, after a predetermined time when the welded portion is determined to be poorly welded by the first determining means, the welded portion that is determined to be poorly welded is the welded portion that is captured by the image capturing means. 4. The laser welding quality determination device according to claim 3, wherein the second image processing determination unit is controlled to analyze the optical image and determine the welding state of the weld based on the analyzed image analysis result.

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