Laser welding system with OCT (optical coherence tomography) online detection function

Abstract

The utility model relates to the technical field of laser welding, in particular to a laser welding system with an OCT (optical coherence tomography) online detection function, which comprises an OCT device, a laser processing system, an infrared sensor, a computer and a controller. The laser processing system is provided with a laser processing head, and the infrared sensor is used for acquiring a thermal induction temperature image so that the computer can generate a first control parameter; the OCT equipment is connected with the laser processing system through an optical fiber; the OCT equipment is used for providing a spectral interference fringe image for the computer; the computer is used for analyzing and processing the spectral interference fringe image to obtain a second control parameter; the controller is configured to control the laser processing head and adjust welding parameters in real time according to the first control parameter and the second control parameter; according to the laser welding system with the OCT online detection function, accurate welding is achieved, and various laser welding quality problems are effectively recognized.

Description

Technical Field

[0001] The utility model relates to the technical field of laser welding, in particular to a laser welding system with OCT online detection. Background Art

[0002] OCT technology is the limit of the current mature technology for non-destructive detection of industrial laser processes. Compared with ultrasonic detection and X-ray detection, OCT technology has the characteristics of non-destructive, micron resolution, long measurement range, and no radiation. However, the multiple reflections of the OCT detection beam in the metal keyhole will cause the depth information measured by OCT to not accurately reflect the true depth of the keyhole, so it is necessary to make improvements. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a laser welding system with OCT online detection, which scans the front, middle and rear end areas of the molten pool through the detection light beam, and uses the interference principle of light to realize weld tracking, online detection of penetration depth and formed welds respectively, and uses infrared thermal imaging technology to capture the temperature distribution difference of the keyhole in real time to output the internal three-dimensional information of the keyhole, thereby achieving accurate welding and effectively identifying various laser welding quality problems.

[0004] In order to solve the above problems, the utility model adopts the following technical solutions:

[0005] An embodiment provides a laser welding system with OCT online detection, including an OCT device, a laser processing system, an infrared sensor, a computer and a controller.

[0006] The OCT device, laser processing system and infrared sensor are all electrically connected to the computer.

[0007] The laser processing system has a laser processing head. The infrared sensor is fixedly arranged on one side of the laser processing head. The infrared sensor is used to obtain a thermal induction temperature image for the computer to generate a first control parameter.

[0008] An optical fiber is arranged between the OCT device and the laser processing system, and the OCT device and the laser processing system are connected via the optical fiber; the OCT device is used to provide a spectral interference fringe image for the computer.

[0009] The computer is used for analyzing and processing the spectral interference fringe image to obtain a second control parameter.

[0010] The controller is configured to control the laser processing head and adjust welding parameters in real time according to the first control parameter and the second control parameter.

[0011] In a laser welding system with OCT online detection provided by at least one embodiment of the present disclosure, the OCT device includes a low-coherence light source, a spectrometer and a Michelson interferometer.

[0012] In the laser welding system with OCT online detection provided by at least one embodiment of the present disclosure, the spectrometer includes a third collimator, a reflective grating, a first focusing lens and a linear array CCD camera.

[0013] In the laser welding system with OCT online detection provided by at least one embodiment of the present disclosure, the Michelson interferometer includes a fiber coupler, a first collimator, a second collimator, a measuring arm and a reference arm.

[0014] In the laser welding system with OCT online detection provided by at least one embodiment of the present disclosure, the laser processing system further comprises a collimating lens, a scanning galvanometer, a laser galvanometer, a beam splitter, a second focusing lens, a welding robot arm and a laser;

[0015] The laser, laser processing head and welding robot arm are all electrically connected to the controller.

[0016] In the laser welding system with OCT online detection provided by at least one embodiment of the present disclosure, the low-coherence light source and the spectrometer are both connected to the optical fiber coupler.

[0017] In the laser welding system with OCT online detection provided by at least one embodiment of the present disclosure, a filter is further provided between the spectrometer and the optical fiber coupler.

[0018] In the laser welding system with OCT online detection provided by at least one embodiment of the present disclosure, the first parameter is a three-dimensional real-time image of the molten pool.

[0019] In the laser welding system with OCT online detection provided by at least one embodiment of the present disclosure, the second parameter is a curve chart of weld position data, penetration data and formed weld data before processing.

[0020] In the laser welding system with OCT online detection provided by at least one embodiment of the present disclosure, the infrared sensor is an online infrared sensor.

[0021] The beneficial effects of the utility model are:

[0022] At the same time, multiple signals generated by the welding process are collected: signals of the weld position before processing, signals of penetration depth, and signals of the formed weld after processing. Subsequently, by separating the signals of each channel, a single signal or multiple signals can be analyzed and processed, making the system highly flexible and applicable.

[0023] By using the OCT detection beam to scan the weld at the front end of the molten pool, the position information of the weld before processing can be obtained, and the position of the laser processing head and the welding process parameters can be adjusted in time so that the laser can be positioned at the weld for welding, which greatly avoids defects in the welding process caused by deviations in the weld and ensures the accuracy of the system in the actual welding production process.

[0024] The OCT technology used can directly obtain the keyhole depth and weld morphology information of the processing process in real time, which can help us control and optimize the processing quality in real time and locate processing defects.

[0025] The non-destructive testing feature of this system can reduce material loss and has broad application prospects.

[0026] High safety, simple operation, strong adaptability and high detection accuracy.

[0027] Using OCT technology and infrared thermal imaging technology to image the depth or topography information of the machining process in real time and visualize the collected signals can help understand the evolution of the entire machining process and enhance the transparency and functionality of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 The utility model is a schematic diagram of the structure of a laser welding system with OCT online detection.

[0030] Figure 2 It is a three-dimensional distribution diagram of some components of a laser welding system with OCT online detection according to the utility model.

[0031] Figure 3 This is a schematic diagram of component distribution of a laser welding system with OCT online detection according to the utility model.

[0032] In the figure:

[0033] 1. Computer; 2. OCT equipment; 3. Laser processing head; 4. Infrared sensor; 5. Welding robot arm; 6. Laser; 7. Workbench; 8. Controller; 9. Low coherence light source; 10. Spectrometer; 11. Reference arm; 12. Optical fiber; 13. Optical fiber coupler; 14. Filter; 15. Laser galvanometer; 16. Reflective grating; 17. First focusing lens; 18. Linear array CCD camera; 19. Scanning galvanometer. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments will be described clearly and completely below in conjunction with the drawings in the embodiments. Obviously, the described embodiments are only a part of the embodiments, rather than all the embodiments.

[0035] like Figures 1 to 3 As shown, the embodiment provides a laser welding system with OCT online detection, including an OCT device 2, a laser processing system, an infrared sensor 4, a computer 1 and a controller 8.

[0036] The OCT device 2 , the laser processing system and the infrared sensor 4 are all electrically connected to the computer 1 .

[0037] The controller 8 is located in the chassis of the OCT device 2 .

[0038] The laser processing system comprises a laser processing head 3 , and an infrared sensor 4 is fixedly arranged at one side of the laser processing head 3 . The infrared sensor 4 is used to obtain a thermal induction temperature image for the computer 1 to generate a first control parameter.

[0039] An optical fiber 12 is provided between the OCT device 2 and the laser processing system, and the OCT device 2 and the laser processing system are connected via the optical fiber; the OCT device 2 is used to provide a spectral interference fringe image for the computer 1 .

[0040] The computer 1 is used to analyze and process the spectral interference fringe image to obtain the second control parameter.

[0041] The controller 8 is configured to control the laser processing head 3 and adjust the welding parameters in real time according to the first control parameter and the second control parameter.

[0042] In this embodiment, the OCT device 2 includes a low-coherence light source 9, a spectrometer 10 and a Michelson interferometer.

[0043] In this embodiment, the spectrometer 10 includes a third collimator, a reflective grating 16 , a first focusing lens 17 and a linear array CCD camera 18 .

[0044] In this embodiment, the Michelson interferometer includes a fiber coupler 13 , a first collimator, a second collimator, a measuring arm and a reference arm 11 .

[0045] In this embodiment, the laser processing system further comprises a collimating lens, a scanning galvanometer 19, a laser galvanometer 15, a beam splitter, a second focusing lens, a welding robot 5 and a laser 6. The laser processing head 3 and the welding robot 5 are both electrically connected to the controller 8.

[0046] In this embodiment, the low coherence light source 9 and the spectrometer 10 are both connected to the optical fiber coupler 13 .

[0047] In this embodiment, a filter 14 is further arranged between the spectrometer 10 and the optical fiber coupler 13 .

[0048] In this embodiment, the first parameter is a three-dimensional real-time image of the molten pool.

[0049] In this embodiment, the second parameter is a curve chart of weld position data, penetration data and formed weld data before processing.

[0050] In this embodiment, the infrared sensor 4 is an online infrared sensor.

[0051] The working process of the laser welding system with OCT online detection in the embodiment will be disclosed below to further illustrate its working principle.

[0052] like Figure 3 As shown, the workflow of the laser welding system with OCT online detection is as follows:

[0053] The low-coherence light source uses a superluminescent diode (SLD) light source with a wide spectral width and low coherence, thereby achieving higher measurement resolution and particularly precise imaging. The wide-spectrum light source emitted by the SLD is divided into two beams through a fiber coupler, namely the first beam (detection beam) and the second beam (reference beam).

[0054] The first beam passes through the second collimator, and then enters the laser processing head after being filtered by the filter. After being reflected by the scanning galvanometer, it is reflected by the beam splitter and enters the second focusing lens together with the laser beam to focus on the weld of the welded part. By controlling the swing angle of the scanning galvanometer, the angle of the first beam can be changed, so that the first beam can scan the weld area at the front and rear ends of the molten pool and the molten area in the molten pool. ① When the first beam scans the front end area of ​​the molten pool, the first beam scans the surface of the welded part before processing and the joint gap, and then forms reflected light and returns to the fiber coupler along the original path; ② When the first beam scans the molten area at the middle end of the molten pool, wait until the laser beam melts the weld to form a stable keyhole, the first beam enters the bottom of the keyhole to form reflected light and then returns to the fiber coupler along the original path; ③ When the first beam scans the rear end area of ​​the molten pool, the first beam will scan the processed weld, and then form reflected light and return to the fiber coupler along the original path.

[0055] The second light beam enters the reference arm through the first collimator, and then returns to the fiber coupler along the original path after being reflected by the plane mirror.

[0056] The first light beam and the second light beam returning from the measuring arm and the reference arm to the fiber coupler will be superimposed. When the optical path difference between the first light beam and the second light beam matches the coherent wavelength of the light source, interference will occur. The light signal after interference enters the reflective grating through the third collimator. The reflective grating disperses the signal light according to the wavelength. The dispersed light passes through the first focusing lens and is focused on the linear array CCD camera. Then, the spectral interference fringe image is captured. Finally, the image is analyzed and processed by a computer to obtain a curve chart with the weld position data, penetration data and formed weld data before processing. Among them, after obtaining the weld position data before processing, the computer will read the data, control the laser processing head to perform position compensation, position the laser processing head and the weld, realize weld tracking and thus accurately weld; and the curve chart of the penetration data and the formed weld data can reflect the penetration quality and weld quality in real time.

[0057] The infrared sensor measures the actual temperature distribution of the keyhole by scanning the infrared radiation of the current keyhole, converts the temperature data of the keyhole, obtains the thermal induction temperature image, and processes and outputs the molten pool temperature image on the computer. The computer combines and analyzes the molten pool image with the molten pool temperature image to obtain an accurate 3D real-time image of the molten pool, and finally identifies the defects of the molten pool and analyzes the quality of welding. The controller can adjust the welding parameters in real time according to the analyzed welding quality data to improve the subsequent welding quality.

[0058] The first beam (detection beam) scanning working rules are as follows:

[0059] The above working process is a process in which both the first light beam and the laser beam are working. The first light beam is coaxial with the laser beam through the second focusing lens, and both move together with the laser processing head.

[0060] By controlling the swing angle of the scanning galvanometer, the deflection angle of the first light beam in the horizontal and vertical directions can be changed to achieve scanning of the weld in three-dimensional space.

[0061] Although the embodiments of the present application have been shown and described above, the scope of protection of the present invention is not limited thereto, and any changes or substitutions that are not conceivable through creative work should be included in the scope of protection of the present invention; unless explicitly stated, any element, action or instruction used in this document should not be interpreted as critical or necessary.

Claims

1. A laser welding system with OCT online detection, characterized in that: include: OCT equipment, laser processing systems, infrared sensors, computers and controllers; The OCT device, laser processing system and infrared sensor are all electrically connected to the computer; The laser processing system has a laser processing head, the infrared sensor is fixedly arranged on one side of the laser processing head, and the infrared sensor is used to obtain a thermal sensing temperature image for the computer to generate a first control parameter; An optical fiber is provided between the OCT device and the laser processing system, and the OCT device and the laser processing system are connected via the optical fiber; the OCT device is used to provide a spectral interference fringe image for the computer; The computer is used to analyze and process the spectral interference fringe image to obtain a second control parameter; The controller is configured to control the laser processing head and adjust welding parameters in real time according to the first control parameter and the second control parameter.

2. A laser welding system with OCT online detection according to claim 1, characterized in that: The OCT device includes a low-coherence light source, a spectrometer and a Michelson interferometer.

3. A laser welding system with OCT online detection according to claim 2, characterized in that: The spectrometer includes a third collimator, a reflective grating, a first focusing lens and a linear array CCD camera.

4. The laser welding system with OCT online detection according to claim 3 is characterized in that: The Michelson interferometer includes a fiber coupler, a first collimator, a second collimator, a measuring arm and a reference arm.

5. The laser welding system with OCT online detection according to claim 4, characterized in that: The laser processing system also has a collimating lens, a scanning galvanometer, a laser galvanometer, a beam splitter, a second focusing lens, a welding robot arm and a laser; The laser, laser processing head and welding robot arm are all electrically connected to the controller.

6. The laser welding system with OCT online detection according to claim 5, characterized in that: The low-coherence light source and the spectrometer are both connected to the optical fiber coupler.

7. The laser welding system with OCT online detection according to claim 6, characterized in that: A filter is also arranged between the spectrometer and the optical fiber coupler.

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