Depth of fusion detection system and laser welding system

Abstract

The utility model provides a penetration detection system and a laser welding system, the penetration detection system comprises a reference arm, a detection light source and a spectrometer, the detection light source is connected to a light splitting optical fiber coupler, and the light splitting optical fiber coupler splits detection laser into a first emergent light beam and a second emergent light beam; the first emergent light beam is transmitted to the laser welding galvanometer system through a second optical fiber and is reflected at a welding spot to form a first reflected light beam, and the first reflected light beam sequentially passes through the laser welding galvanometer system and the second optical fiber to return to the light splitting optical fiber coupler; the second emergent light beam is transmitted to the reference arm through the third optical fiber and then is reflected by the reference arm to form a second reflected light beam, and the second reflected light beam returns to the light splitting optical fiber coupler through the third optical fiber; and the first reflected light beam and the second reflected light beam are transmitted to the spectrograph through a fourth optical fiber after interfering at the light splitting optical fiber coupler. According to the utility model, the color difference between the detection laser and the welding laser can be effectively corrected, and the detection quality of OCT on penetration detection is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of laser welding penetration detection, in particular to a penetration detection system and a laser welding system. Background Technique

[0002] With the continuous development of laser technology, laser welding has become the mainstream method of welding processing, with many advantages such as non-contact and high efficiency, and is widely used in industries such as automobiles, hardware, 3C electronics, and new energy batteries. Welding penetration, as a key indicator to measure welding quality, has attracted much attention in the industry.

[0003] OCT (Optical Coherence Tomography) is applied to the field of laser welding penetration detection and can detect penetration well. In the application of galvanometer laser processing, due to the parallel beam of the incident field lens having a certain angle and the detection laser and the welding laser having a wavelength difference, resulting in chromatic aberration, it is difficult for the detection laser and the welding laser to be focused on the same position at different processing positions, affecting the penetration detection effect. Content of the Utility Model

[0004] Aiming at the deficiencies of the prior art, the first object of the utility model is to provide a penetration detection system, which can effectively correct the chromatic aberration between the detection laser and the welding laser, thereby improving the detection effect and quality of OCT in penetration detection.

[0005] The embodiments of the utility model are realized through the following technical solutions:

[0006] A penetration detection system includes a reference arm, a detection light source, and a spectrometer, wherein: the detection light source is used to emit a detection laser, the detection light source is connected to a spectroscopic fiber coupler through a first optical fiber, and the spectroscopic fiber coupler is used to split the detection laser into a first output beam and a second output beam; the first output beam is transmitted through a second optical fiber to a laser welding galvanometer system and is reflected at the welding point to form a first reflected beam, and the first reflected beam sequentially passes through the laser welding galvanometer system and the second optical fiber and returns to the spectroscopic fiber coupler; the second output beam is transmitted through a third optical fiber to the reference arm, and after being reflected by the reference arm, it forms a second reflected beam, and the second reflected beam returns to the spectroscopic fiber coupler through the third optical fiber; the first reflected beam and the second reflected beam interfere at the spectroscopic fiber coupler and are then transmitted to the spectrometer through a fourth optical fiber.

[0007] According to a preferred embodiment, a polarization isolator is provided on the first optical fiber, and the polarization isolator is located between the detection light source and the spectroscopic fiber coupler.

[0008] According to a preferred embodiment, the reference arm includes a first focusing lens group, a first collimating lens group, and a reflective gold mirror, where: the second output beam passes through the first collimating lens group and the first focusing lens group in sequence and then reaches the reflective gold mirror for reflection to form the second reflected beam, and the second reflected beam passes through the first focusing lens group and the first collimating lens group in sequence to reach the third optical fiber.

[0009] According to a preferred embodiment, it further includes a second collimating lens group and a detection galvanometer system. The first output beam is transmitted to the second collimating lens group through a second optical fiber for collimation and then enters the detection galvanometer system, and finally enters the laser welding galvanometer system.

[0010] According to a preferred embodiment, the detection galvanometer system includes a first detection galvanometer mirror and a second detection galvanometer mirror. The first detection galvanometer mirror is driven by a first motor, and the second detection galvanometer mirror is driven by a second motor.

[0011] According to a preferred embodiment, the optical fiber splitter coupler is a 5:5 optical fiber splitter coupler.

[0012] Another object of the present invention is a laser welding system, including a welding light source, a laser welding galvanometer system, and the aforementioned melt depth detection system. The welding light source is used to emit a welding laser beam, and after the welding laser beam enters the laser welding galvanometer system, it is coaxially transmitted with the first output beam to the workpiece to be welded.

[0013] According to a preferred embodiment, the laser welding galvanometer system includes a first welding galvanometer, a second welding galvanometer, a third motor, and a fourth motor. Among them, the third motor is used to drive the first welding galvanometer, and the fourth motor is used to drive the second welding galvanometer; the welding laser beam passes through the first welding galvanometer and the second welding galvanometer in sequence to the workpiece to be welded.

[0014] According to a preferred embodiment, the laser welding system further includes a vision detection lens and a vision detection camera. The vision detection camera cooperates with the vision detection lens to assist in welding.

[0015] The technical solution of the embodiment of the present invention has at least the following advantages and beneficial effects:

[0016] In the process of applying the OCT technology to the detection of the melt depth of laser welding, the present invention can realize the color difference correction of online detection, supplement the offset of the detection laser so that it can be coaxial with the welding laser, and thus can improve the accuracy of the melt depth detection. Description of the Drawings

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the attached drawings required for the embodiments. It should be understood that the following attached drawings only show some embodiments of the present invention, and therefore should not be regarded as a limitation of the scope. For those of ordinary skill in the art, without creative efforts, other related attached drawings can also be obtained based on these attached drawings.

[0018] Figure 1 It is a flowchart of the color difference correction method for online detection of penetration depth in the embodiments of the present invention;

[0019] Figure 2 It is a 25-point matrix structure diagram in the machining plane in the embodiments of the present invention;

[0020] Figure 3 It is a three-dimensional analysis schematic diagram of the X-axis offset in the embodiments of the present invention;

[0021] Figure 4 It is a schematic diagram of the bilinear interpolation algorithm in the embodiments of the present invention;

[0022] Figure 5 It is a schematic diagram of the relative position between the detection light focus and the welding laser focus in the embodiments of the present invention;

[0023] Figure 6 It is a schematic diagram of the position after the detection light focus and the welding laser focus are aligned in the embodiments of the present invention;

[0024] Figure 7 It is a schematic diagram of the scanning path of the detection galvanometer system during scanning imaging in the embodiments of the present invention;

[0025] Figure 8 It is a scanning imaging diagram using the reflectivity information of the measured points in the embodiments of the present invention;

[0026] Figure 9 It is a scanning imaging diagram using the height information of the measured points in the embodiments of the present invention;

[0027] Figure 10 The interference spectrum signal and signal demodulation result diagram of the detection laser in the embodiments of the present invention;

[0028] Figure 11 It is an effect diagram of the detection galvanometer system scanning the weld pool at the center of the field of view in the embodiments of the present invention;

[0029] Figure 12 It is a schematic diagram of the welding keyhole in the embodiments of the present invention;

[0030] Figure 13 It is a schematic diagram of several forms of high-frequency swinging of the detection laser galvanometer around the welding point during the penetration depth detection in the embodiments of the present invention;

[0031] Figure 14 This is a schematic structural diagram of the laser welding system in the embodiment of the present utility model.

[0032] Icons: 100 - welding laser, 200 - detection laser, 300 - processing plane, 400 - weld spot, O1 - center point, O2 - reference point, 1 - fifth optical fiber, 2 - third collimator group, 3 - beam combiner, 4 - laser welding galvanometer system, 5 - third motor, 6 - first welding galvanometer, 7 - fourth motor, 8 - second welding galvanometer, 9 - field lens, 10 - workpiece to be welded, 11 - processing point, 12 - second optical fiber, 13 - second collimator group, 14 - detection galvanometer system, 15 - first motor, 16 - first detection galvanometer mirror, 17 - second motor, 18 - second detection galvanometer mirror, 19 - detection light reflector, 20 - vision detection lens, 21 - vision detection camera, 22 - detection light source, 23 - first optical fiber, 24 - polarization isolator, 25 - spectroscopic fiber coupler, 26 - third optical fiber, 27 - first collimator group, 28 - first focusing lens group, 29 - reflective gold mirror, 30 - fourth optical fiber, 31 - spectrometer. Specific embodiments

[0033] For better understanding and implementation, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model.

[0034] Please refer to Figures 1 to 11 , a color difference correction method for online detection of the penetration depth of two-dimensional galvanometer laser welding, comprising the following steps:

[0035] S1: Determine any solder joint within the welding area as the center point O1;

[0036] S2: Adjust the welding laser 100 and the detection laser 200 so that they are aligned at the center point O1;

[0037] S3: Taking the center point O1 as the center, select several points around the center point O1 as the reference points O2, and record the reference offset of the detection laser 200 relative to the specific reference point O2 when the welding laser 100 is at the reference point O2;

[0038] S4: Based on the coordinate data of the reference points O2 and the reference offset data of the detection laser 200, perform bilinear interpolation calculation on the coordinate data of any solder joint within the welding area to obtain the actual offset of the detection laser 200 relative to the solder joint, and then perform offset compensation on the detection laser 200 through the actual offset.

[0039] Specifically, in step S1, it is preferable to select the center solder joint of the welding area as the center point O1, such as Figure 2As shown, a number of reference points O2 are distributed in an equally spaced square matrix. Such a setting facilitates the execution of step S3, specifically for facilitating the detection of the reference offset data of the detection laser 200 when the welding laser 100 is at the corresponding reference point O2.

[0040] In Figure 2 it is set that the coordinates of the center point O1 are the point (0, 0), and based on this, a 25-point equally spaced square matrix is established. At the same time, an X - O1 - Y plane coordinate system is established, and on this basis, the longitudinal direction is set as the Z axis to establish a spatial rectangular coordinate system O1 - XYZ. The specific size of the reference point O2, which is also the solder joint, is determined according to the actual welding requirements. It should be noted that the color difference correction method for online detection of the penetration depth provided in this embodiment is applicable to a two-dimensional galvanometer. That is, when in use, the distance between the galvanometer and the surface of the workpiece to be welded, that is, the processing plane 300, remains the same in the longitudinal direction. Here, an example is given where the welding area coincides with the processing plane 300 in the longitudinal direction. Specifically, the offset galvanometer uses the welding laser 100 to make a 25-point solder joint matrix as shown in Figure 2 on the processing plane 300. Since the welding laser 100 and the detection laser 200 are only aligned at the center point O1, due to the color difference between the detection laser 200 and the welding laser 100, at other points, that is, the reference point O2, when the spot of the welding laser 100 is aligned with the reference point O2, the spot of the detection laser 200 will be offset by a certain distance relative to the spot of the welding laser 100 on the surface of the workpiece to be welded. Then, after the welding galvanometer is sequentially offset to each reference point O2, through the small-area scanning of the detection galvanometer system, the sizes of the X-axis and Y-axis offsets of the spot of the detection laser 200 relative to the corresponding weld spot 400 of each reference point O2 in the scanning image are obtained in the processing field of view, that is, the processing plane 300, and the coordinate information of the reference point O2 and the X-axis and Y-axis offsets, that is, the reference offset data, are recorded.

[0041] On the X - O1 - Y plane, a three-dimensional analysis of the Z-axis offset is performed based on the X-axis offset, and it is observed that the X-axis offset is a non-linear characteristic. Similarly, a three-dimensional analysis of the Z-axis offset is performed based on the Y-axis offset, and it is observed that the Y-axis offset is a non-linear characteristic. It should be noted that the Z-axis offset is the offset of the focus of the detection laser 200 relative to the focus of the welding laser 100. As shown in Figure 3 it can be seen from the three-dimensional image of the X-axis offset and the Y-axis offset and the position of the focus of the welding laser 100 on the surface of the workpiece to be welded that the three-dimensional fitting image of the offset values of the 25-point matrix shows a non-single linear characteristic.

[0042] Based on the non-linear characteristics of the X-axis offset and the Y-axis offset, single linear interpolation cannot meet the color difference compensation requirements. The present application uses bilinear interpolation.

[0043] Within the welding area, define the coordinates of any point P as (x, y), where the integer parts of its coordinates are i = [x] and j = [y], and define u = x - i and v = y - j as the offsets of x and y relative to the integer coordinates, respectively.

[0044] The bilinear interpolation formula is as follows:

[0045]

[0046] Bilinear interpolation can improve the spatial resolution and visual quality of data by performing smooth interpolation on discrete data, making it possible to conduct more refined analysis and processing of discrete data in a continuous space.

[0047] In a specific implementation, the steps for performing bilinear interpolation on two-dimensional discrete data f(i, j) are as follows:

[0048] First, perform the first interpolation in the X-axis direction:

[0049] f interp1 (i + u, j) = (1 - u)f(i, j) + uf(i + 1, j);

[0050] where u is the offset of x relative to i, and i and j are the integer part coordinates of x and y, respectively.

[0051] Then, perform the second interpolation in the X-axis direction:

[0052] f interp2 (i + u, j) = (1 - u)f interp1 (i, j) + uf interp1 (i + 1, j);

[0053] Now, perform interpolation in the Y-axis direction on the obtained f interp2 (i + u, j):

[0054]

[0055] where v is the offset of y relative to j.

[0056] Through the above steps, bilinear interpolation can be performed on the coordinates (x, y) of any point P on a two-dimensional discrete data grid to smooth and reconstruct the discrete data, improving the continuity and accuracy of the data.

[0057] In this embodiment, specifically as Figure 4 shown, perform bilinear interpolation on any point P in the X - O1 - Y plane. The position of point P in the 25 - point matrix is as Figure 2 shown by the position of the dashed box. Specifically, Figure 4 the meanings of the letters in

[0058] P: The target point to be found;

[0059] Px, Py: The coordinates of point P;

[0060] f(Px): The actual offset of the target point P in the X-axis direction;

[0061] f(Py): The actual offset of the target point P in the Y-axis direction;

[0062] A1: In the 25-point correction matrix, the top-left matrix point closest to point P;

[0063] A1x, A1y: The coordinates of matrix point A1;

[0064] f(Ax): The X-axis offset of point A1;

[0065] f(Ay): The Y-axis offset of point A1;

[0066] B1: In the 25-point correction matrix, the top-right matrix point closest to point P;

[0067] B1x, B1y: The coordinates of matrix point B1;

[0068] f(Bx): The X-axis offset of point B1;

[0069] f(By): The Y-axis offset of point B1;

[0070] C1: In the 25-point correction matrix, the bottom-left matrix point closest to point P;

[0071] C1x, C1y: The coordinates of matrix point C1;

[0072] f(Cx): The X-axis offset of point C1;

[0073] f(Cy): The Y-axis offset of point C1;

[0074] D1: In the 25-point correction matrix, the bottom-right matrix point closest to point P;

[0075] D1x, D1y: The coordinates of matrix point D1;

[0076] f(Dx): The X-axis offset of point D1;

[0077] f(Dy): The Y-axis offset of point D1;

[0078] Draw an auxiliary line passing through point P and perpendicular to the X-axis, and the intersection point with line A1B1 is P1, and the intersection point with line C1D1 is P2.

[0079] P1x, P1y: The coordinates of point P1;

[0080] f(P1x): The X-axis offset of point P1;

[0081] f(P1y): The Y-axis offset of point P1;

[0082] P2x, P2y: The coordinates of point P2;

[0083] f(P2x): The X-axis offset of point P2;

[0084] f(P2y): The Y-axis offset of point P2;

[0085] Perform the first interpolation in the X-axis direction:

[0086]

[0087] Perform the second interpolation in the X-axis direction:

[0088]

[0089] Perform the interpolation in the Y-axis direction:

[0090]

[0091] Similarly, the actual Y-axis offset f(Py) of point P can be obtained. Based on the above actual offset, by detecting the swing of the galvanometer system to perform offset compensation on the detection laser 200, the color difference correction for on-line detection can be realized, and thus the accuracy of the penetration depth detection can be improved.

[0092] It should be noted that in this embodiment, 25 points are used as an example for illustration. In other embodiments, other forms or numbers of point forms can also be selected.

[0093] Furthermore, the center point O1 is in the processing plane 300, and S2 includes the following steps:

[0094] S21: In the processing plane 300, align the focus of the welding laser 100 with the focus of the detection laser 200;

[0095] S22: In the direction perpendicular to the processing plane 300, align the focus of the welding laser 100 with the focus of the detection laser 200.

[0096] Specifically, as Figure 5 and Figure 6As shown in the figure, aligning the detection laser 200 with the welding laser 100 at the center point O1 includes aligning in the X-axis and Y-axis directions and making the focal points of the two coincide in the Z-axis direction. In this embodiment, first, the detection laser 200 and the welding laser 100 are coaxially arranged in the machining plane 300, that is, the X-O1-Y plane, and finally, the focal points of the detection laser 200 and the welding laser 100 are both made to coincide within the machining plane 300. In another embodiment, the order of step S21 and step S22 can be swapped or they can be carried out simultaneously.

[0097] Further, in the direction perpendicular to the machining plane 300, aligning the focal point of the welding laser 100 with the focal point of the detection laser 200 includes:

[0098] S221: Performing Fourier transform on the interference spectrum of the detection laser 200 to obtain a spectrum demodulation signal;

[0099] S222: Adjusting the exit position of the detection laser 200 of the detection optical fiber so that the reflection surface of the detection laser 200 is within the beam waist range of the focused beam of the detection laser 200 until the intensity of the spectrum demodulation signal is the maximum.

[0100] Between step S1 and step S2, it also includes: performing Fourier transform on the interference spectrum of the detection laser 200 to obtain the height information and reflectivity information of the center point O1. When in use, first, a weld spot 400 is formed at the center point O1 on the machining plane 300 by the welding laser 100, and then the detection laser 200 detection path as shown in Figure 7 is used to scan and image the weld spot 400 at the center point O1.

[0101] For example, by digitally scanning a steel ruler, a Figure 8 shown reflectivity intensity image can be obtained, where different gray values represent the reflectivities of different measurement points. At the same time, a Figure 9 shown height image can be obtained, where different colors represent the heights of different measured points.

[0102] Specifically, since the wavelengths of the detection laser 200 and the welding laser 100 are different, they will not be focused on the same plane after passing through the same focusing system. By adjusting the exit position of the detection laser 200, according to the object-image relationship, the focal point position will move in the same direction as the image point position. According to the confocal principle, when the reflection surface of the detection laser 200 is within the beam waist range of the detection laser 200 beam, the most detection laser 200 returns to the system. As shown in Figure 10 According to the spectrum demodulation signal data, when the intensity of the spectrum demodulation signal is the maximum, the focal points of the detection laser 200 and the welding laser 100 are focused on the same plane, achieving the alignment of the two in the Z-axis direction. Subsequently, the welding laser 100 irradiates at the center point O1 to form a Figure 7The solder spot 400 shown is scanned by the above-mentioned detection laser 200 scanning method, and the emissivity information of the measured points is used for imaging to obtain as Figure 11 the solder spot 400 shown. By using the alignment auxiliary line, the center of the crosshair is aligned with the center of the solder spot 400, that is, the center of the field of view of the offset detection galvanometer system is offset to the center of the solder spot 400 in the scanned image, so as to achieve the alignment of the X-axis and Y-axis directions of the welding laser 100 and the detection laser 200.

[0103] In this embodiment, a method for detecting the penetration depth is also provided, including the following steps:

[0104] S01: Discretize the welding path of the two-dimensional galvanometer to obtain a number of solder joints;

[0105] S02: Configure the detection laser 200 coaxial with the welding laser 100, and perform offset compensation on the detection laser 200 at all solder joints through the above-mentioned color difference correction method for on-line detection of the penetration depth of two-dimensional galvanometer laser welding.

[0106] In this way, accurate penetration depth detection can be carried out on each solder joint on the welding path in real time online.

[0107] Furthermore, as Figure 12 shown, for the welding keyhole structure, the detection laser 200 needs to enter the inside of the welding keyhole and act on the bottom of the welding keyhole to measure the accurate penetration depth value. Since the reference offset amount of the detection laser 200 is fitting data, there must be a certain error, and the size of the opening of the welding keyhole is very small. Therefore, in practice, there is a possibility that the detection laser 200 exceeds the opening range of the welding keyhole after offset compensation. Therefore, after S02, the following steps are also included: the detection laser 200 swings at the solder joint. Specifically, during the welding process, the galvanometer is controlled to make the detection laser 200 swing at a high frequency within a small range, so as to increase the probability of the detection laser 200 smoothly entering the welding keyhole, and further obtain more effective penetration depth data.

[0108] Specifically, as Figure 13 shown, the detection laser 200 swings linearly along the tangent direction of the welding direction, and / or the detection laser 200 swings linearly along the vertical direction of the welding laser 100, and / or the detection laser 200 swings circumferentially around the solder joint.

[0109] In this embodiment, the swing frequency of the detection laser 200 is not less than 1000HZ. Optionally, the swing frequency is 6250HZ, 3125HZ or 1562.5HZ.

[0110] In this embodiment, the swing amplitude of the detection laser 200 does not exceed 100 um. Optionally, when it swings linearly, the swing line length is 20 um, 50 um, or 80 um. When it swings in a circle, the swing radius is 20 um, 50 um, or 80 um.

[0111] As Figure 14 shown, in this embodiment, a penetration depth detection system is also provided for performing the foregoing penetration depth detection method, including a reference arm, a detection light source 22, and a spectrometer 31, where: the detection light source 22 is used to emit a detection laser 200, and the detection light source 22 is connected to a spectroscopic fiber coupler 25 through a first optical fiber 23. The spectroscopic fiber coupler 25 is used to split the detection laser 200 into a first outgoing beam and a second outgoing beam; the first outgoing beam is transmitted through a second optical fiber 12 to a laser welding galvanometer system 4 and reflected at the welding point to form a first reflected beam. The first reflected beam sequentially passes through the laser welding galvanometer system 4 and the second optical fiber 12 and returns to the spectroscopic fiber coupler 25; after the second outgoing beam is transmitted through a third optical fiber 26 to the reference arm, a second reflected beam is formed after reflection by the reference arm. The second reflected beam returns to the spectroscopic fiber coupler 25 through the third optical fiber 26; the first reflected beam and the second reflected beam interfere at the spectroscopic fiber coupler 25 and are then transmitted through a fourth optical fiber 30 to the spectrometer 31. In this embodiment, the second optical fiber 12 is the foregoing detection optical fiber.

[0112] Further, a polarization isolator 24 is provided on the first optical fiber 23, and the polarization isolator 24 is located between the detection light source 22 and the spectroscopic fiber coupler 25. The polarization isolator 24 can prevent the reflected beam from returning to the detection light source 22 and plays a role in protecting the detection light source 22.

[0113] In this embodiment, the reference arm includes a first focusing lens group 28, a first collimating lens group 27, and a reflective gold mirror 29, where: the second outgoing beam sequentially passes through the first collimating lens group 27 and the first focusing lens group 28 and then reaches the reflective gold mirror 29 for reflection to form a second reflected beam. The second reflected beam sequentially passes through the first focusing lens group 28 and the first collimating lens group 27 and reaches the third optical fiber 26.

[0114] The penetration depth detection system further includes a second collimating lens group 13 and a detection galvanometer system 14. The first outgoing beam is transmitted through the second optical fiber 12 to the second collimating lens group 13 for collimation and then enters the detection galvanometer system 14, and finally enters the laser welding galvanometer system 4.

[0115] Specifically, the detection galvanometer system 14 includes a first detection galvanometer mirror 16 and a second detection galvanometer mirror 18. The first detection galvanometer mirror 16 is driven by a first motor 15, and the second detection galvanometer mirror 18 is driven by a second motor 17.

[0116] In this embodiment, a laser welding system is further provided, which includes a welding light source (not shown in the figure), a laser welding galvanometer system 4, and the aforementioned penetration depth detection system. The welding light source is used to emit 100 beams of welding laser. After the 100 beams of welding laser enter the laser welding galvanometer system 4, they are coaxially transmitted to the workpiece 10 to be welded with the first output beam.

[0117] Further, the laser welding galvanometer system 4 includes a first welding galvanometer 6, a second welding galvanometer 8, a third motor 5, and a fourth motor 7. Among them, the third motor 5 is used to drive the first welding galvanometer 6, and the fourth motor 7 is used to drive the second welding galvanometer 8; the 100 beams of welding laser sequentially pass through the first welding galvanometer 6 and the second welding galvanometer 8 to the workpiece 10 to be welded.

[0118] During use, the detection laser 200 emitted by the detection light source 22 is split into a first output beam and a second output beam by the spectroscopic fiber coupler 25. The first output beam is transmitted along the second optical fiber 12 to the second collimating lens group 13, collimated and then enters the detection galvanometer system 14, specifically passing through the first detection galvanometer mirror 16 and the second detection galvanometer mirror 18 in sequence, and then reaching the beam combining mirror 3 through the detection light emitting mirror; at the same time, the 100 beams of welding laser emitted by the welding light source pass through the fifth optical fiber 1 to the third collimating lens group 2, and then transmitted to the beam combining mirror 3 to be combined with the first output beam, that is, the detection laser 200 and the welding laser 100 are combined to form a welding detection composite beam. The welding detection composite beam enters the laser welding galvanometer system 4, is reflected by the first welding galvanometer 6 and the second welding galvanometer 8, and exits through the field lens 9 to the processing plane 300 of the workpiece 10 to be welded. The 100 beams of welding laser generate a welding keyhole at the processing point 11 on the workpiece 10 to be welded. The detection laser 200, that is, the first output beam, is reflected after entering the welding keyhole to form a first reflected beam. The first reflected beam returns to the spectroscopic fiber coupler 25 along the optical path. The second output beam passes through the first collimating lens group 27 and the first focusing lens group 28 in sequence and then reaches the reflecting gold mirror 29 to be reflected to form a second reflected beam. The second reflected beam passes through the first focusing lens group 28 and the first collimating lens group 27 in sequence and then returns to the spectroscopic fiber coupler 25 to interfere and superpose with the first reflected beam. The interference light is transmitted through the fourth optical fiber 30 to the spectrometer 31 to obtain an interference spectrum signal, and the penetration depth of each solder joint on the welding path is detected based on the aforementioned penetration depth detection method.

[0119] In this embodiment, the spectroscopic fiber coupler 25 is a 5:5 spectroscopic fiber coupler.

[0120] In this embodiment, as Figure 14As shown, it further includes a detection optical mirror 19, a vision detection lens 20, and a vision detection camera 21. The first output light beam reaches the beam combiner 3 through the detection optical mirror 19. The vision detection camera 21 cooperates with the vision detection lens 20 to assist in welding. Specifically, the auxiliary crosshairs in the imaging screen of the vision detection camera 21 are used as a reference to facilitate finding the welding position.

[0121] The technical means disclosed in the solution of the present utility model are not limited to the technical means disclosed in the above embodiments, and also include technical solutions composed of any combination of the above technical features. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present utility model, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present utility model.

Claims

1. A penetration depth detection system, characterized in that, Comprising a reference arm, a detection light source, and a spectrometer, wherein: The detection light source is used to emit detection laser light. The detection light source is connected to a spectroscopic fiber coupler through a first optical fiber. The spectroscopic fiber coupler is used to split the detection laser light into a first output beam and a second output beam; The first output beam is transmitted through a second optical fiber to a laser welding galvanometer system, and is reflected at the welding point to form a first reflected beam. The first reflected beam sequentially passes through the laser welding galvanometer system and the second optical fiber and returns to the spectroscopic fiber coupler; The second output beam is transmitted through a third optical fiber to the reference arm, and after being reflected by the reference arm, forms a second reflected beam. The second reflected beam returns to the spectroscopic fiber coupler through the third optical fiber; The first reflected beam and the second reflected beam interfere at the spectroscopic fiber coupler and are then transmitted through a fourth optical fiber to the spectrometer.

2. The melt depth detection system according to claim 1, characterized in that, A polarization isolator is provided on the first optical fiber, and the polarization isolator is located between the detection light source and the spectroscopic fiber coupler.

3. The penetration depth detection system according to claim 1, characterized in that The reference arm includes a first focusing lens group, a first collimating lens group, and a reflective gold mirror, wherein: The second output beam sequentially passes through the first collimating lens group and the first focusing lens group and then reaches the reflective gold mirror for reflection to form the second reflected beam. The second reflected beam sequentially passes through the first focusing lens group and the first collimating lens group and reaches the third optical fiber.

4. The penetration depth detection system according to claim 1, characterized in that It further includes a second collimating lens group and a detection galvanometer system. The first output beam is transmitted through the second optical fiber to the second collimating lens group for collimation and then enters the detection galvanometer system, and finally enters the laser welding galvanometer system.

5. The penetration depth detection system according to claim 4, wherein The detection galvanometer system includes a first detection galvanometer mirror and a second detection galvanometer mirror. The first detection galvanometer mirror is driven by a first motor, and the second detection galvanometer mirror is driven by a second motor.

6. The melt depth detection system according to claim 1, characterized in that, The spectroscopic fiber coupler is a 5:5 spectroscopic fiber coupler.

7. A laser welding system, characterized in that, Comprising a welding light source, a laser welding galvanometer system, and a penetration depth detection system according to any one of claims 1-6. The welding light source is used to emit a welding laser beam. After the welding laser beam enters the laser welding galvanometer system, it is coaxially transmitted with the first output beam to the workpiece to be welded.

8. The laser welding system according to claim 7, characterized in that, The laser welding galvanometer system includes a first welding galvanometer, a second welding galvanometer, a third motor, and a fourth motor. Among them, the third motor is used to drive the first welding galvanometer, and the fourth motor is used to drive the second welding galvanometer; The welding laser beam sequentially passes through the first welding galvanometer and the second welding galvanometer to the workpiece to be welded.

9. The laser welding system according to claim 7, wherein The laser welding system further includes a vision detection lens and a vision detection camera. The vision detection camera cooperates with the vision detection lens to assist in welding.

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