Laser autogenous welding system and method

Abstract

The present application discloses a laser autogenous welding system and method, which relates to the field of welding. The system includes a laser welding execution module, a detection module, a database module, and an intelligent control module. The laser welding execution module is used to weld the workpiece to be welded; the detection module is connected to the laser welding execution module and is used to collect interference spectra in real time; the database module is used to store preset thresholds; the intelligent control module is electrically connected to the detection module, the database module, and the laser welding execution module. The intelligent control module is used to analyze the interference spectra to obtain weld information and judge the quality of the weld after welding based on the comparison result between the weld information and the preset threshold. The weld information includes the depth of the molten pool keyhole obtained by analyzing the interference spectrum of the signal at the bottom of the molten pool keyhole, and the width and height of the weld after welding obtained by analyzing the interference spectrum of the weld morphology. The present application can quickly complete the evaluation of the quality of the weld after welding, so that repair welding can be performed at the corresponding position, thereby improving welding efficiency.

Description

Technical Field

[0001] The present application relates to the field of welding technology, and in particular to a laser autogenous welding system and method. Background Art

[0002] Laser autogenous welding has the advantages of high energy density, concentrated heating, minimal thermal damage to the material, a large weld depth-to-width ratio, low residual stress in the weld joint, and high welding precision. In recent years, its application in the field of aviation titanium alloy processing has become increasingly widespread. For example, laser autogenous welding is often used to process titanium alloy frame beam components in aircraft.

[0003] Titanium alloy structural components are extremely valuable, and yield requirements are extremely stringent. However, titanium alloys are inherently reflective of laser light, and the plasma generated during welding reduces laser power, making them more susceptible to defects during welding. Therefore, weld quality assessment is necessary after welding to ensure timely repairs are taken to address potential defects. However, existing laser welding equipment is unable to quickly assess weld quality, resulting in low efficiency. Summary of the Invention

[0004] The main purpose of this application is to provide a laser autogenous welding system and method, aiming to solve the problem that existing laser welding equipment cannot quickly evaluate the weld quality and has low working efficiency.

[0005] To achieve the above-mentioned objectives, the present application provides a laser autogenous welding system, which includes a laser welding execution module, a detection module, a database module and an intelligent control module. The laser welding execution module is used to weld the workpiece to be welded; the detection module is connected to the laser welding execution module, and the detection module is used to collect interference spectra in real time, wherein the interference spectrum includes the interference spectrum of the signal at the bottom of the molten pool keyhole and the interference spectrum of the weld morphology; the database module is used to store preset thresholds, wherein the preset thresholds include the plate thickness value of the workpiece to be welded, the range of the weld width after welding, and the range of the weld height after welding; the intelligent control module is electrically connected to the detection module, the database module and the laser welding execution module, and the intelligent control module is used to parse the interference spectrum to obtain weld information, and judge the quality of the weld after welding based on the comparison result of the weld information and the preset threshold, wherein the weld information includes the molten pool keyhole depth obtained by parsing the interference spectrum of the signal at the bottom of the molten pool keyhole, and the weld width and weld height after welding obtained by parsing the weld morphology interference spectrum.

[0006] Optionally, the database module is also used to store welding process information, and the preset threshold also includes a range of weld width before welding and a range of weld step difference before welding; the weld information also includes a weld width before welding and a weld step difference before welding obtained by analyzing the weld morphology interference spectrum; the intelligent control module is also used to match the corresponding welding process information based on a comparison result of the weld width before welding, the weld step difference before welding and the preset threshold, and output a first control signal to the laser welding execution module, wherein the first control signal is used to instruct the laser welding execution module to perform welding based on the corresponding welding process information.

[0007] Optionally, the preset threshold also includes the center position of the weld trajectory; the weld information also includes the center position of the weld obtained by analyzing the weld morphology interference spectrum; the intelligent control module is also used to determine the trajectory deviation value based on the weld center position and the weld trajectory center position and output a second control signal to the laser welding execution module, wherein the second control signal is used to instruct the laser welding execution module to realize welding trajectory offset.

[0008] Optionally, the laser welding execution module includes a laser welding head and an actuator, the laser welding head is connected to the detection module; the actuator is connected to the laser welding head, and the actuator is electrically connected to the intelligent control module; wherein the actuator is used to drive the laser welding head to perform welding.

[0009] Optionally, the detection module includes a light source, an optical detection module and an optical measurement module, and a first measurement light fiber interface, a second measurement light fiber interface and a reference light fiber interface are provided on the periphery of the optical detection module, the first measurement light fiber interface is connected to the light source through a measurement light fiber, and the reference light fiber interface is connected to the light source through a reference light fiber; a third measurement light fiber interface is provided on the periphery of the optical measurement module, and the third measurement light fiber interface is connected to the second measurement light fiber interface through the measurement light fiber, wherein the optical measurement module is connected to the laser welding head.

[0010] Optionally, the first measuring light fiber interface is perpendicular to the second measuring light fiber interface, and the second measuring light fiber interface is parallel to the reference light fiber interface; the optical detection module includes a first cavity, a first dichroic mirror, a grating, a focusing mirror and a camera, the first dichroic mirror is arranged in the first cavity and is located in the measuring light path direction of the first measuring light fiber interface; in the measuring light path direction of the second measuring light fiber interface and the reference light path direction of the reference light fiber interface, a grating, a focusing mirror and a camera are arranged inside the first cavity and are sequentially away from the first dichroic mirror; wherein, the first measuring light fiber interface and the second measuring light fiber interface are both located on the side of the first dichroic mirror away from the grating.

[0011] Optionally, the optical measurement module includes a second cavity, a second dichroic mirror and a swinging galvanometer, the second cavity is connected to the laser welding head, and the third measurement light fiber interface is located on the side of the second cavity away from the laser welding head; in the measurement light path direction of the third measurement light fiber interface, a second dichroic mirror and a swinging galvanometer are arranged inside the second cavity, which are sequentially away from the third measurement light fiber interface, wherein a channel is provided on the laser welding head for the light path reflected by the swinging galvanometer to intersect with the workpiece to be welded; a plane reflective lens is provided on one side of the second dichroic mirror in a first direction, and the first direction is perpendicular to the measurement light path direction of the third measurement light fiber interface.

[0012] In addition, to achieve the above-mentioned purpose, an embodiment of the present application also provides a laser autogenous melting welding method, which is applied to the above-mentioned laser autogenous melting welding system, and the method is executed by an intelligent control module, and the method includes real-time acquisition of an interference spectrum, wherein the interference spectrum includes a signal interference spectrum at the bottom of a molten pool keyhole and a weld morphology interference spectrum; determining weld information based on the interference spectrum, wherein the weld information includes a molten pool keyhole depth obtained by analyzing the signal interference spectrum at the bottom of the molten pool keyhole, and a post-weld weld width and a post-weld weld excess height obtained by analyzing the weld morphology interference spectrum; obtaining a preset threshold, wherein the preset threshold includes a plate thickness value of a workpiece to be welded, a post-weld weld width range, and a post-weld weld excess height range; and judging the quality of the weld after welding based on a comparison result between the weld information and the preset threshold.

[0013] Optionally, before determining the weld information based on the interference spectrum, the method also includes determining the pre-weld weld width and the pre-weld weld step difference based on the weld morphology interference spectrum analysis; obtaining the pre-weld weld width range, the pre-weld weld step difference range and the welding process information; comparing the pre-weld weld width with the pre-weld weld width range; comparing the pre-weld weld step difference with the pre-weld weld step difference range; if the pre-weld weld width is within the pre-weld weld width range and the pre-weld weld step difference is within the pre-weld weld step difference range, matching the corresponding welding process information and outputting a first control signal to the laser welding execution module, wherein the first control signal is used to instruct the laser welding execution module to perform welding based on the corresponding welding process information.

[0014] Optionally, before determining the weld information based on the interference spectrum, the method also includes obtaining the center position of the weld trajectory; obtaining the center position of the weld based on the weld morphology interference spectrum analysis; determining a trajectory deviation value based on the weld trajectory center position and the weld center position, and outputting a second control signal to the laser welding execution module, wherein the second control signal is used to instruct the laser welding execution module to realize welding trajectory offset.

[0015] Optionally, the weld information is determined based on the interference spectrum, including determining whether the signal interference spectrum of the bottom keyhole of the molten pool is obtained; if the signal interference spectrum of the bottom keyhole of the molten pool is not obtained, the weld has been fully melted after welding, and the depth of the molten pool keyhole is a fixed value and is less than the thickness of the workpiece to be welded; if the signal interference spectrum of the bottom keyhole of the molten pool is obtained, the depth of the molten pool keyhole is determined based on the signal interference spectrum of the bottom keyhole of the molten pool, and the weld width and weld excess height after welding are determined based on the weld morphology interference spectrum.

[0016] Optionally, the post-weld weld quality is judged based on the comparison result of the weld information with the preset threshold, including judging whether the post-weld weld is fully melted based on the comparison result of the molten pool keyhole depth and the thickness value of the workpiece to be welded; judging whether the post-weld weld width is qualified based on the comparison result of the post-weld weld width and the post-weld weld width range; judging whether the post-weld weld height is qualified based on the comparison result of the weld reinforcement and the weld reinforcement range; if the post-weld weld is fully melted, the post-weld weld width is qualified and the post-weld weld reinforcement is qualified, then the post-weld weld quality is qualified; if the post-weld weld is not fully melted or the post-weld weld width is unqualified or the post-weld weld reinforcement is unqualified, then the post-weld weld quality is unqualified.

[0017] Optionally, judging whether the weld after welding is fully melted based on the comparison result of the molten pool keyhole depth and the plate thickness value of the workpiece to be welded includes comparing the molten pool keyhole depth with the plate thickness value of the workpiece to be welded; if the molten pool keyhole depth is greater than or equal to the plate thickness value of the workpiece to be welded, the weld after welding is fully melted; if the molten pool keyhole depth is less than the plate thickness value of the workpiece to be welded, the weld is not fully melted.

[0018] Optionally, the judging whether the post-weld weld width is qualified based on the comparison result between the post-weld weld width and the post-weld weld width range includes comparing the post-weld weld width with the post-weld weld width range; if the post-weld weld width is within the post-weld weld width range, the post-weld weld width is qualified; if the post-weld weld width is outside the post-weld weld width range, the post-weld weld width is unqualified.

[0019] Optionally, judging whether the post-weld weld reinforcement is qualified based on the comparison result between the weld reinforcement and the weld reinforcement range includes comparing the weld reinforcement with the weld reinforcement range; if the weld reinforcement is within the weld reinforcement range, the weld reinforcement is qualified; if the weld reinforcement is outside the weld reinforcement range, the weld reinforcement is unqualified.

[0020] A laser autogenous welding system proposed in an embodiment of the present application, in which, during the process of workpiece welding performed by the laser welding execution module, the detection module obtains the signal interference spectrum of the bottom keyhole of the molten pool and the weld morphology interference spectrum in real time, and the intelligent control module analyzes the signal interference spectrum of the bottom keyhole of the molten pool and the weld morphology interference spectrum to obtain the molten pool keyhole depth, the weld seam width after welding and the weld seam residual height after welding, and compares the molten pool keyhole depth, the weld seam width after welding and the weld seam residual height after welding with the corresponding preset thresholds stored in the database module. If the weld seam after welding is fully melted, the weld seam width after welding is qualified and the weld seam residual height after welding is qualified, the weld seam quality after welding is qualified; if the weld seam after welding is not fully melted or the weld seam width after welding is unqualified or the weld seam residual height after welding is unqualified, the weld seam quality after welding is unqualified; in this way, the weld quality evaluation after welding can be completed quickly, so that repair welding can be performed in the corresponding position in time, greatly improving the welding efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the overall structure of a laser autogenous welding system provided as an example for the implementation of this application;

[0022] Figure 2 This is a structural diagram of the optical detection module implemented in this application;

[0023] Figure 3 This is a structural diagram of the optical measurement module implemented in this application;

[0024] Figure 4 A flow chart of a laser autogenous welding method provided in an embodiment of the present application;

[0025] Figure 5 A flowchart for implementing process adaptive matching in an embodiment of the present application;

[0026] Figure 6 This is a flowchart for implementing pre-weld positioning and weld tracking in the embodiment of the present application;

[0027] Figure 7 This is a flow chart for determining weld penetration according to an embodiment of the present application;

[0028] Figure 8 This is a flow chart for determining the weld width and residual quality of the weld after welding according to an embodiment of the present application.

[0029] In the figure: 11. Light source; 12. Optical detection module; 121. First measuring light fiber interface; 122. First dichroic mirror; 123. Grating; 124. Focusing mirror; 125. Second measuring light fiber interface; 126. Reference light fiber interface; 127. First cavity; 128. Camera; 129. First water-cooling joint; 13. Optical measurement module; 131. Plane reflective lens; 132. Swinging galvanometer; 133. Second dichroic mirror; 134. Second cavity; 135. Third measuring light fiber interface; 136. Second water-cooling joint; 14. Measuring light fiber; 15. Reference light fiber; 2. Database module; 3. Intelligent control module; 31. Optical signal cable; 41. Laser welding head; 42. Actuator.

[0030] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0032] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0033] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0034] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0035] refer to Figures 1 to 3 , an embodiment of the present application provides a laser autogenous welding system, which may include a laser welding execution module, a detection module, a database module 2 and an intelligent control module 3, the laser welding execution module is used to weld the workpiece to be welded; the detection module is connected to the laser welding execution module, the detection module is used to collect interference spectra in real time, wherein the interference spectrum may include the interference spectrum of the signal at the bottom of the molten pool keyhole and the interference spectrum of the weld morphology; the database module 2 is used to store preset thresholds, wherein the preset thresholds may include the plate thickness value of the workpiece to be welded, the range of the weld width after welding and the range of the weld height after welding; the intelligent control module 3 is electrically connected to the detection module, the database module 2 and the laser welding execution module, the intelligent control module 3 is used to analyze the interference spectrum to obtain weld information, and judge the quality of the weld after welding based on the comparison result of the weld information and the preset threshold, the weld information may include the molten pool keyhole depth obtained by analyzing the interference spectrum of the signal at the bottom of the molten pool keyhole, and the weld width and weld height after welding obtained by analyzing the weld morphology interference spectrum.

[0036] A laser autogenous welding system proposed in an embodiment of the present application, during the process of workpiece welding performed by the laser welding execution module, the detection module obtains the signal interference spectrum of the bottom keyhole of the molten pool and the weld morphology interference spectrum in real time, and the intelligent control module 3 analyzes the signal interference spectrum of the bottom keyhole of the molten pool and the weld morphology interference spectrum to obtain the molten pool keyhole depth, the weld seam width after welding and the weld seam residual height after welding, and compares the molten pool keyhole depth, the weld seam width after welding and the weld seam residual height after welding with the corresponding preset thresholds stored in the database module 2. If the weld seam after welding is fully melted, the weld seam width after welding is qualified and the weld seam residual height after welding is qualified, then the weld seam quality after welding is qualified; if the weld seam after welding is not fully melted or the weld seam width after welding is unqualified or the weld seam residual height after welding is unqualified, then the weld seam quality after welding is unqualified; in this way, the evaluation of the weld quality after welding can be completed quickly, so that repair welding can be performed in the corresponding position in time, greatly improving the welding efficiency.

[0037] The intelligent control module 3 automatically obtains the interference spectrum detected by the detection module and the preset threshold value in the database module 2.

[0038] It should be noted that when the weld is fully melted after welding, the molten pool keyhole may completely penetrate the workpiece, which will cause the detection module to be unable to obtain the signal interference spectrum at the bottom of the molten pool keyhole. At this time, the intelligent control module 3 can determine that the weld is fully melted after welding.

[0039] It should be understood that the intelligent control module 3 includes an industrial computer and a set of intelligent welding software. The intelligent control module 3 is electrically connected to the detection module through an optical signal cable 31. The industrial computer is equipped with a CPU and a GPU. The CPU is used for system feature algorithm calculation, and the GPU is used for parallel calculation of the algorithm to achieve high-speed real-time processing of interference signals.

[0040] In an exemplary embodiment, the database module 2 is also used to store welding process information, and the preset threshold value may also include the pre-weld weld width range and the pre-weld weld step difference range; the weld information may also include the pre-weld weld width and the pre-weld weld step difference obtained by weld morphology interference spectrum analysis; the intelligent control module 3 is also used to match the corresponding welding process information based on the comparison result of the pre-weld weld width, the pre-weld weld step difference and the preset threshold value and output a first control signal to the laser welding execution module, wherein the first control signal is used to instruct the laser welding execution module to perform welding based on the corresponding welding process information.

[0041] Specifically, before starting welding, the detection module will obtain the weld morphology interference spectrum, and then the intelligent control module 3 will analyze the weld morphology interference spectrum to obtain the weld seam width before welding and the weld seam step difference before welding; the intelligent control module 3 will judge whether the weld seam width before welding and the weld seam step difference before welding are qualified based on the weld seam width range before welding and the weld seam step difference range before welding. If the weld seam width before welding and the weld seam step difference before welding are both qualified, the appropriate welding process information will be matched and the first control signal will be output to the laser welding execution module; if the weld seam width before welding is unqualified or the weld seam step difference before welding is unqualified, it should be prompted to reassemble the workpiece to be welded.

[0042] Among them, if the weld width before welding is within the weld width range before welding, the weld width before welding is qualified, otherwise it is unqualified; if the weld step difference before welding is within the weld step difference range before welding, the weld step difference before welding is qualified, otherwise it is unqualified.

[0043] It should be understood that when the workpiece to be welded is assembled and qualified, the intelligent control module 3 can send corresponding welding process information to the laser welding execution module based on the pre-weld weld seam width and pre-weld weld seam step difference of the workpiece to be welded to instruct the laser welding execution module to perform automatic welding; in this way, the pre-weld weld seam width and pre-weld weld seam step difference of different workpieces to be welded can be automatically measured, and the welding process parameters can be automatically matched, which reduces the time required for manual measurement and judgment, improves processing efficiency, and combines the above-mentioned scheme to automatically judge the welding quality after welding is completed, which can further improve welding work efficiency.

[0044] For example, after the automatic welding is completed, the welding quality is judged. If the weld height after welding is unqualified, the intelligent control module 3 can match the corresponding process information to control the laser welding execution module to perform repair welding on the weld so that the weld height after welding is qualified. In this way, the weld quality can be quickly judged, and repair welding measures can be taken on potential defects in time to ensure processing reliability.

[0045] In addition, the database storage module is mainly used to store welding process information such as laser power, welding speed, swing mode, and swing frequency.

[0046] In an exemplary embodiment, the preset threshold may also include the center position of the weld trajectory; the weld information may also include the center position of the weld obtained by analyzing the weld morphology interference spectrum; the intelligent control module 3 is also used to determine the trajectory deviation value based on the weld center position and the weld trajectory center position and output a second control signal to the laser welding execution module, wherein the second control signal is used to instruct the laser welding execution module to realize the welding trajectory offset.

[0047] Specifically, after the intelligent control module 3 compares the center position of the weld with the center position of the weld trajectory, it can obtain the trajectory deviation value, and convert the trajectory deviation value into an analog signal and output it to the laser welding execution module to control the laser welding execution module to achieve trajectory offset, thereby realizing the positioning before welding and tracking during welding for conventional welds or long-distance narrow welds. It has strong versatility and can adapt to complex parts and fixtures of different shapes.

[0048] refer to Figure 1 In an exemplary embodiment, the laser welding execution module may include a laser welding head 41 and an actuator 42, the laser welding head 41 is connected to the detection module; the actuator 42 is connected to the laser welding head 41, and the actuator 42 is electrically connected to the intelligent control module 3; wherein the actuator 42 is used to drive the laser welding head 41 to perform welding.

[0049] Specifically, the laser welding head 41 can be a swing galvanometer welding laser head, and the actuator 42 can be a six-axis robot. The laser welding head 41 is connected to the actuator 42 through a mounting flange, so that the actuator 42 can drive the laser welding head 41 to perform welding operations.

[0050] refer to Figure 1 and Figure 2 In an exemplary embodiment, the detection module may include a light source 11, an optical detection module 12 and an optical measurement module 13. The optical detection module 12 is provided with a first measurement light fiber interface 121, a second measurement light fiber interface 125 and a reference light fiber interface 126 on the periphery thereof. The first measurement light fiber interface 121 is connected to the light source 11 through a measurement light fiber 14, and the reference light fiber interface 126 is connected to the light source 11 through a reference light fiber 15; the optical measurement module 13 is provided with a third measurement light fiber interface 135 on the periphery thereof. The third measurement light fiber interface 135 is connected to the second measurement light fiber interface 125 through a measurement light fiber 14, wherein the optical measurement module 13 is connected to the laser welding head 41.

[0051] It should be noted that the light source 11 can be a laser, the spectral range of the light source 11 is 600-700nm, and the central wavelength is 650±100nm; the measurement light fiber 14 and the reference light fiber 15 are respectively led out from the light source 11 and connected to the optical detection module 12, and the optical detection module 12 and the optical measurement module 13 are also connected through the measurement light fiber 14.

[0052] refer to Figure 2In an exemplary embodiment, the first measurement light fiber interface 121 is perpendicular to the second measurement light fiber interface 125, and the second measurement light fiber interface 125 is parallel to the reference light fiber interface 126; the optical detection module 12 may include a first cavity 127, a first dichroic mirror 122, a grating 123, a focusing mirror 124 and a camera 128, the first dichroic mirror 122 is arranged in the first cavity 127 and is located in the measurement light path direction of the first measurement light fiber interface 121; in the measurement light path direction of the second measurement light fiber interface 125 and the reference light path direction of the reference light fiber interface 126, the first cavity 127 is provided with a grating 123, a focusing mirror 124 and a camera 128, which are sequentially away from the first dichroic mirror 122; wherein the first measurement light fiber interface 121 and the second measurement light fiber interface 125 are both located on the side of the first dichroic mirror 122 away from the grating 123.

[0053] The camera 128 is a linear array CCD camera.

[0054] It should be noted that the first dichroic mirror 122 and focusing lens 124 are mounted separately via mounting brackets. The mounting brackets have built-in water-cooling channels, which circulate cooling water to cool each lens. A first water-cooling connector 129 is provided outside the cavity, connected to a Φ6 outer diameter water-cooling tube via a quick-connect connector. The focal length of the focusing lens is 150 mm. The linear array CCD camera has a measurement range of 600-700 nm and a sampling frequency of ≥250 kHz.

[0055] refer to Figure 3 In an exemplary embodiment, the optical measurement module 13 may include a second cavity 134, a second dichroic mirror 133 and a swinging galvanometer 132, the second cavity 134 is connected to the laser welding head 41, and the third measurement light fiber interface 135 is located on the side of the second cavity 134 away from the laser welding head 41; in the direction of the measurement light path of the third measurement light fiber interface 135, the second dichroic mirror 133 and the swinging galvanometer 132 are arranged inside the second cavity 134, which are sequentially away from the third measurement light fiber interface 135, wherein a channel is provided on the laser welding head 41 for the light path reflected by the swinging galvanometer 132 to intersect with the workpiece to be welded; a plane reflective lens 131 is provided on one side of the second dichroic mirror 133 in a first direction, and the first direction is perpendicular to the measurement light path direction of the third measurement light fiber interface 135.

[0056] The first measurement light fiber interface 121 , the second measurement light fiber interface 125 , the reference light fiber interface 126 and the third measurement light fiber interface 135 are all FC interfaces; wherein the second cavity 134 can be connected to the laser welding head 41 by bolts.

[0057] It should be noted that the second dichroic mirror 133, the oscillating galvanometer mirror 132, and the plane reflective lens 131 are all installed in the second cavity 134 through mounting brackets. The mounting brackets have built-in water-cooling channels, and each lens is cooled by circulating cooling water. A second water-cooling joint 136 is provided outside the second cavity 134, and the second water-cooling joint 136 is connected to a water-cooling pipe with an outer diameter of Φ6 through a quick-connect joint.

[0058] Specifically, when the system is in operation, the laser first emits a detection laser with a wavelength of 650 nm. This detection laser travels along the measurement optical fiber 14 to the optical detection module 12. After being reflected by the first dichroic mirror 122, it travels through the measurement optical fiber 14 to the optical measurement module 13. After transmitting through the second dichroic mirror 133, the detection laser passes through the oscillating galvanometer 132 and the optical path of the laser welding head 41, irradiating the surface of the weld object. After being reflected, it returns along the original optical path, passing through the first dichroic mirror 122 and reaching the grating 123. After being reflected by the second dichroic mirror 133, the detection laser strikes the plane reflector 131, where it is also reflected, returns along the original optical path, passes through the first dichroic mirror 122 and reaches the grating 123. The laser then emits a reference laser with similar composition to the detection laser, which travels through the reference optical fiber 15 to reach the grating 123. The reflected detection laser and the reference laser interfere at the grating 123, spreading out according to wavelength to form an interference light pattern. The camera 128 performs sampling via the focusing mirror 124 to obtain a one-dimensional interference spectrum, which is finally transmitted to the intelligent control module 3 in the form of an interference spectrum.

[0059] Before welding begins, the detection laser scans the surface of the workpiece to be welded, and the interference spectrum of the weld morphology is obtained through the detection module. After the intelligent control module 3 analyzes the interference spectrum, it obtains the height information of different positions on the workpiece surface, and can obtain the weld seam width and weld step difference before welding to determine whether the assembly is qualified.

[0060] Before and during welding, the detection laser scans the weld in real time, and the interference spectrum of the weld morphology is obtained through the detection module. After the intelligent control module 3 analyzes the interference spectrum, the center position of the weld is calculated, and the center position of the weld is compared with the center position of the weld trajectory set in the database module 2. The trajectory deviation value is calculated, and the deviation value is converted into an analog signal and output to the laser welding execution module, so that the laser welding execution module can realize the trajectory offset, realize the positioning before welding and tracking during welding for conventional welds or long-distance narrow welds, and has strong versatility and can adapt to complex parts and fixtures of different shapes.

[0061] The existing paraxial tracking system has a weld recognition accuracy of >0.2mm when the distance between the titanium alloy butt weld and the workpiece exceeds 300mm, which does not meet the welding requirements of complex titanium alloy structures. To ensure recognition accuracy, it can only be installed at the front end of the welding head, which takes up a large installation space and is very likely to interfere with the parts. If interference occurs, the paraxial tracking system can only be removed and the welding can be completed through manual teaching, which reduces processing efficiency. Figure 3 As shown, the measurement end, or optical measurement module 13, is mounted on the laser welding head 41, allowing the system's measurement optical path to be coaxial with the welding laser optical path. This means that both the detection laser and the welding laser ultimately exit the channel on the laser welding head 41 onto the workpiece to be welded, and the detection laser and welding laser overlap. This minimizes the space occupied by the detection module and significantly reduces interference between the system and the workpiece or its clamping fixture during welding. Furthermore, the system utilizes the aforementioned pre-weld positioning and in-weld tracking functions, achieving an identification accuracy of 0.1 mm at a distance of 300-400 mm from the workpiece, meeting the welding requirements for complex titanium alloy structures.

[0062] During welding, the detection laser scans the weld pool keyhole in real time. The detection module obtains the interference spectrum of the signal at the bottom of the weld pool keyhole. After analyzing the interference spectrum, the intelligent control module 3 calculates the real-time weld pool keyhole depth. If no valid depth signal is returned, that is, the detection module does not obtain the interference spectrum of the signal at the bottom of the weld pool keyhole, it is determined that the keyhole completely penetrates the workpiece and the weld is fully melted. If a valid depth signal is returned, the depth of the weld pool keyhole is compared with the workpiece thickness. If the depth of the weld pool keyhole is greater than the workpiece thickness, the weld is determined to be fully melted. If the depth of the weld pool keyhole is less than or equal to the workpiece thickness, the weld is determined to be partially melted, thus completing the weld penetration determination.

[0063] After welding is completed, the weld formed by laser scanning is detected, and the weld morphology interference spectrum is obtained through the detection module. After the intelligent control module 3 analyzes the interference spectrum, the weld width and weld excess height after welding are obtained, and the weld width and weld excess height after welding are judged to be unqualified.

[0064] Among them, the process characteristics of titanium alloy laser autogenous welding, such as easy reflection of laser and welding plasma reducing laser power, and based on the conditions that the weld has been fully melted, the weld width after welding is qualified, and the weld excess height after welding is qualified, the weld quality can be quickly judged.

[0065] refer to Figures 4 to 8 On the basis of the above embodiment, the embodiment of the present application further provides a laser autogenous welding method, which is applied to the above laser autogenous welding system. The method is executed by the intelligent control module 3 and may specifically include the following steps:

[0066] S100, acquiring an interference spectrum in real time, wherein the interference spectrum may include an interference spectrum of a signal at the bottom of a molten pool keyhole and an interference spectrum of a weld morphology;

[0067] S200, determining weld information based on the interference spectrum, wherein the weld information may include a molten pool keyhole depth obtained by analyzing the interference spectrum of a signal at the bottom of the molten pool keyhole, and a post-weld weld width and a post-weld weld reinforcement obtained by analyzing the weld morphology interference spectrum;

[0068] S300, obtaining a preset threshold, wherein the preset threshold may include a thickness value of a workpiece to be welded, a range of a weld seam width after welding, and a range of a weld seam excess height after welding;

[0069] S400: Determine the quality of the weld after welding based on a comparison result between the weld information and a preset threshold.

[0070] In step S100, the interference spectrum is acquired by scanning the workpiece with a detection laser in the detection module.

[0071] In step S300 , the preset threshold value may be set in advance in the database module 2 and then acquired by the intelligent control module 3 .

[0072] In step S400, the depth of the molten pool keyhole and the thickness of the workpiece to be welded can be used to quickly determine whether the weld is fully melted, the weld width after welding and the weld width range after welding can be used to quickly determine whether the weld width after welding is qualified, and the weld height after welding and the weld height range after welding can be used to quickly determine whether the weld height after welding is qualified; in this way, based on the judgment of whether the weld is fully melted, whether the weld width after welding is qualified, and whether the weld height after welding is qualified, the weld quality can be quickly judged, thereby effectively improving the welding work efficiency.

[0073] refer to Figure 5 In an exemplary embodiment, before step S200, the method may further include the following steps:

[0074] S110, determining the weld width and weld step before welding based on weld morphology interference spectrum analysis;

[0075] S120, obtaining a pre-weld weld width range, a pre-weld weld step range, and welding process information;

[0076] S130, comparing the weld seam width before welding with the weld seam width range before welding;

[0077] S140, comparing the weld step difference before welding with the weld step difference range before welding;

[0078] S150. If the weld seam width before welding is within the weld seam width range before welding and the weld seam step difference before welding is within the weld seam step difference range before welding, the corresponding welding process information is matched and a first control signal is output to the laser welding execution module, wherein the first control signal is used to instruct the laser welding execution module to perform welding based on the corresponding welding process information.

[0079] In step S120 , the pre-weld weld width range, pre-weld weld step difference range, and welding process information can all be set in advance in the database module 2 and then acquired by the intelligent control module 3 .

[0080] Among them, in step S150, if the weld seam width before welding is within the weld seam width range before welding and the weld seam step difference before welding is within the weld seam step difference range before welding, the intelligent control module 3 will match the welding process information corresponding to the weld seam width before welding and the weld seam step difference before welding, store it in the first control signal and send it to the laser welding execution module to instruct the laser welding execution module to perform welding according to the corresponding welding process information, complete automatic matching of the welding process, and realize automatic welding.

[0081] In addition, if the weld seam width before welding is not within the weld seam width range before welding or the weld seam step difference before welding is not within the weld seam step difference range before welding, the assembly of the workpiece to be welded is unqualified, and the intelligent control module 3 can prompt to reassemble. The specific prompt method is not limited here. A sound prompt can be issued, or a display screen can be added to directly display relevant information about unqualified assembly.

[0082] refer to Figure 6 In an exemplary embodiment, before step S200, the method may further include the following steps:

[0083] S160, obtaining the center position of the weld trajectory;

[0084] S170, the center position of the weld is obtained based on the weld morphology interference spectrum analysis;

[0085] S180. Determine a trajectory deviation value based on the weld trajectory center position and the weld center position, and output a second control signal to the laser welding execution module, wherein the second control signal is used to instruct the laser welding execution module to implement welding trajectory offset.

[0086] Among them, in step S160, the center position of the weld trajectory is also stored in the database module 2 and matches the welding process information set in advance in the database module 2. The intelligent control module 3 obtains the center position of the welding trajectory corresponding to the welding process information.

[0087] In step S180, the actuator 42 receives the first control signal to realize the displacement of the motion trajectory of the laser welding head 41, ensuring that the center position of the weld coincides with the center position of the weld trajectory in real time, realizing positioning before welding and tracking during welding, wherein the actuator 42 is a six-axis robot.

[0088] refer to Figure 7 In an exemplary embodiment, step S200 may specifically include the following steps:

[0089] S210, determining whether a signal interference spectrum of the bottom of the molten pool keyhole is obtained;

[0090] S220: If the interference spectrum of the signal at the bottom of the molten pool keyhole is not obtained, the weld has penetrated the molten pool keyhole to a fixed depth that is greater than the thickness of the workpiece to be welded.

[0091] S230. If the signal interference spectrum of the bottom of the molten pool keyhole is obtained, the depth of the molten pool keyhole is determined based on the signal interference spectrum of the bottom of the molten pool keyhole, and the weld width and weld excess height after welding are determined based on the weld morphology interference spectrum.

[0092] Among them, in step S210, during the welding process, when the weld is fully melted, the molten pool keyhole may completely penetrate the workpiece, so the detection module cannot obtain the signal interference spectrum at the bottom of the molten pool keyhole; therefore, it is necessary to determine whether the detection module obtains the signal interference spectrum at the bottom of the molten pool keyhole.

[0093] In step S220, if the interference spectrum of the signal at the bottom of the molten pool keyhole is not obtained, a virtual molten pool keyhole depth can be set, and this depth is greater than the thickness of the workpiece to be welded.

[0094] In an exemplary embodiment, step S400 may specifically include the following steps:

[0095] S410, judging whether the weld is fully penetrated after welding based on a comparison result of the molten pool keyhole depth and the thickness of the workpiece to be welded;

[0096] S420, judging whether the weld seam width after welding is qualified based on the comparison result between the weld seam width after welding and the weld seam width range after welding;

[0097] S430, judging whether the weld reinforcement after welding is qualified based on the comparison result of the weld reinforcement and the weld reinforcement range;

[0098] S440. If the weld is fully penetrated, the weld width is qualified, and the weld reinforcement is qualified, the weld quality is qualified.

[0099] S450. If the weld is not fully melted after welding, or the weld width after welding is unqualified, or the weld height after welding is unqualified, the weld quality after welding is unqualified.

[0100] In step S440 and step S450, the weld quality is qualified only when the weld is fully melted, the weld width is qualified, and the weld excess is qualified. Otherwise, the weld quality is unqualified and needs to be repaired.

[0101] refer to Figure 7 In an exemplary embodiment, step S410 may specifically include the following steps:

[0102] S411, comparing the keyhole depth of the molten pool with the thickness of the workpiece to be welded;

[0103] S412. If the keyhole depth of the molten pool is greater than or equal to the thickness of the workpiece to be welded, the weld is fully melted after welding.

[0104] S413. If the keyhole depth of the molten pool is less than the thickness of the workpiece to be welded, the weld is not fully melted.

[0105] In step 412 , when the interference spectrum of the signal at the bottom of the molten pool keyhole is not obtained, it is recorded that the depth of the molten pool keyhole is greater than the thickness of the workpiece to be welded, that is, the weld is fully melted.

[0106] In step S413, if the weld is not fully melted, the weld may be repaired to make the weld fully melted.

[0107] refer to Figure 8 In an exemplary embodiment, step S420 may specifically include the following steps:

[0108] S421. Compare the weld seam width after welding with the weld seam width range after welding;

[0109] S422. If the weld seam width after welding is within the weld seam width range after welding, the weld seam width after welding is qualified;

[0110] S423. If the weld seam width after welding is outside the weld seam width range after welding, the weld seam width after welding is unqualified.

[0111] Among them, in step S423, if the weld seam width after welding is unqualified, the weld can be repaired to make the weld seam width after welding within the weld seam width range after welding.

[0112] refer to Figure 8 In an exemplary embodiment, step S430 may specifically include the following steps:

[0113] S431. Compare the weld reinforcement and the weld reinforcement range;

[0114] S432. If the weld reinforcement is within the weld reinforcement range, the weld reinforcement is qualified;

[0115] S433. If the weld reinforcement is outside the weld reinforcement range, the weld reinforcement is unqualified.

[0116] Among them, in step S433, if the weld reinforcement after welding is unqualified, the weld can be repaired to make the weld reinforcement after welding within the weld width range.

[0117] in, Figure 8 The characteristic parameters refer to the weld seam width and weld seam reinforcement after welding, the weld seam width range and weld seam reinforcement range after welding; and the weld seam width after welding corresponds to the weld seam width range after welding, and the weld reinforcement after welding corresponds to the weld reinforcement range after welding.

[0118] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A laser autogenous welding system, characterized in that: include: Laser welding execution module, used for welding the workpiece to be welded; A detection module connected to the laser welding execution module, the detection module is used to collect interference spectra in real time, wherein the interference spectra include interference spectra of signals at the bottom of the keyhole of the molten pool and interference spectra of weld morphology; A database module (2) is used to store preset thresholds, wherein the preset thresholds include the thickness of the workpiece to be welded, the range of the weld seam width after welding, and the range of the weld seam height after welding; An intelligent control module (3) is electrically connected to the detection module, the database module (2) and the laser welding execution module, and the intelligent control module (3) is used to analyze the interference spectrum to obtain weld information, and judge the quality of the weld after welding based on the comparison result of the weld information and the preset threshold value, wherein the weld information includes the depth of the molten pool keyhole obtained by analyzing the interference spectrum of the signal at the bottom of the molten pool keyhole, and the width of the weld after welding and the residual height of the weld after welding obtained by analyzing the interference spectrum of the weld morphology.

2. The laser autogenous welding system according to claim 1, characterized in that: The database module (2) is also used to store welding process information, and the preset threshold value also includes a weld seam width range before welding and a weld seam step difference range before welding; The weld information also includes the weld width before welding and the weld step difference before welding obtained by analyzing the weld morphology interference spectrum; The intelligent control module (3) is further used to match corresponding welding process information based on a comparison result of the pre-weld weld seam width, the pre-weld weld seam step difference and a preset threshold value and output a first control signal to the laser welding execution module, wherein the first control signal is used to instruct the laser welding execution module to perform welding based on the corresponding welding process information.

3. The laser autogenous welding system according to claim 1, characterized in that: The preset threshold also includes the center position of the weld track; The weld information also includes the weld center position obtained by analyzing the weld morphology interference spectrum; The intelligent control module (3) is further used to determine a trajectory deviation value based on the weld center position and the weld trajectory center position and output a second control signal to the laser welding execution module, wherein the second control signal is used to instruct the laser welding execution module to implement welding trajectory deviation.

4. The laser autogenous welding system according to claim 1, characterized in that: The laser welding execution module includes: A laser welding head (41) connected to the detection module; An actuator (42) is connected to the laser welding head (41), and the actuator (42) is electrically connected to the intelligent control module (3); Wherein, the actuator (42) is used to drive the laser welding head (41) to perform welding.

5. The laser autogenous welding system according to claim 4, characterized in that: The detection module includes: Light source (11); An optical detection module (12) is provided with a first measuring light fiber interface (121), a second measuring light fiber interface (125), and a reference light fiber interface (126) on its periphery, wherein the first measuring light fiber interface (121) is connected to the light source (11) via a measuring light fiber (14), and the reference light fiber interface (126) is connected to the light source (11) via a reference light fiber (15); An optical measurement module (13) is provided with a third measurement optical fiber interface (135) on its periphery, the third measurement optical fiber interface (135) and the second measurement optical fiber interface (125) being connected via the measurement optical fiber (14), wherein the optical measurement module (13) is connected to the laser welding head (41).

6. The laser autogenous welding system according to claim 5, characterized in that: The first measuring optical fiber interface (121) is perpendicular to the second measuring optical fiber interface (125), and the second measuring optical fiber interface (125) is parallel to the reference optical fiber interface (126); the optical detection module (12) comprises: a first cavity (127); a first dichroic mirror (122) disposed in the first cavity (127) and located in the direction of the measuring light path of the first measuring light fiber interface (121); In the direction of the measurement light path of the second measurement light fiber interface (125) and the direction of the reference light path of the reference light fiber interface (126), a grating (123), a focusing mirror (124), and a camera (128) are provided inside the first cavity (127) and are sequentially spaced away from the first dichroic mirror (122); The first measurement light fiber interface (121) and the second measurement light fiber interface (125) are both located on a side of the first dichroic mirror (122) facing away from the grating (123).

7. The laser autogenous welding system according to claim 5, characterized in that: The optical measurement module (13) comprises: A second cavity (134) is connected to the laser welding head (41), and the third measuring light fiber interface (135) is located on a side of the second cavity (134) facing away from the laser welding head (41); In the direction of the measuring light path of the third measuring light fiber interface (135), a second dichroic mirror (133) and an oscillating galvanometer (132) are provided inside the second cavity (134), which are sequentially away from the third measuring light fiber interface (135), wherein a channel is provided on the laser welding head (41) so that the light path reflected by the oscillating galvanometer (132) intersects with the workpiece to be welded; A plane reflective lens (131) is provided on one side of the second dichroic mirror (133) in a first direction, and the first direction is perpendicular to the direction of the measuring light path of the third measuring light fiber interface (135).

8. A laser autogenous welding method, characterized in that: Applied to the laser autogenous welding system according to any one of claims 1 to 7, the method is executed by the intelligent control module (3), and the method comprises: Acquire interference spectra in real time, wherein the interference spectra include interference spectra of signals at the bottom of the keyhole of the molten pool and interference spectra of weld morphology; Determining weld information based on the interference spectrum, wherein the weld information includes a molten pool keyhole depth obtained by analyzing the interference spectrum of the molten pool keyhole bottom signal, and a post-weld weld width and a post-weld weld reinforcement obtained by analyzing the weld morphology interference spectrum; Obtaining a preset threshold value, wherein the preset threshold value includes a thickness value of a workpiece to be welded, a range of a weld seam width after welding, and a range of a weld seam height after welding; The quality of the weld after welding is judged based on a comparison result between the weld information and the preset threshold.

9. The laser self-melting welding method according to claim 8, characterized in that: Before determining the weld information based on the interference spectrum, the method further includes: Determine the weld width and weld step before welding based on the weld morphology interference spectrum analysis; Obtain the weld width range and weld step range before welding and welding process information; comparing the weld seam width before welding with the weld seam width range before welding; comparing the pre-weld weld step difference with the pre-weld weld step difference range; If the pre-weld weld seam width is within the pre-weld weld seam width range and the pre-weld weld seam step difference is within the pre-weld weld seam step difference range, the corresponding welding process information is matched and a first control signal is output to the laser welding execution module, wherein the first control signal is used to instruct the laser welding execution module to perform welding based on the corresponding welding process information.

10. The laser self-melting welding method according to claim 8, characterized in that: Before determining the weld information based on the interference spectrum, the method further includes: Get the center position of the weld trajectory; Determining the center position of the weld based on the weld morphology interference spectrum analysis; A trajectory deviation value is determined based on the weld trajectory center position and the weld center position, and a second control signal is output to the laser welding execution module, wherein the second control signal is used to instruct the laser welding execution module to implement welding trajectory offset.

11. The laser self-melting welding method according to claim 8, wherein: Determining weld information based on the interference spectrum includes: Determine whether the signal interference spectrum of the bottom of the keyhole of the molten pool is obtained; If the interference spectrum of the signal at the bottom of the molten pool keyhole is not obtained, the weld has been fully melted, and the depth of the molten pool keyhole is a fixed value and is less than the thickness of the workpiece to be welded; If the signal interference spectrum of the bottom of the molten pool keyhole is obtained, the molten pool keyhole depth is determined based on the signal interference spectrum of the bottom of the molten pool keyhole, and the weld width and weld excess height after welding are determined based on the weld morphology interference spectrum.

12. The laser self-melting welding method according to claim 8, wherein: The judging of the weld quality after welding based on the comparison result between the weld information and the preset threshold value includes: Determining whether the weld is fully penetrated after welding based on a comparison result of the molten pool keyhole depth and the thickness of the workpiece to be welded; Determining whether the post-weld weld seam width is qualified based on a comparison result between the post-weld weld seam width and the post-weld weld seam width range; Determining whether the weld reinforcement after welding is qualified based on a comparison result between the weld reinforcement and the weld reinforcement range; If the weld seam after welding has been fully penetrated, the weld seam width after welding is qualified, and the weld seam reinforcement after welding is qualified, the weld seam quality after welding is qualified; If the weld seam after welding is not fully penetrated or the weld seam width after welding is unqualified or the weld reinforcement after welding is unqualified, the quality of the weld seam after welding is unqualified.

13. The laser self-melting welding method according to claim 12, wherein: The determining whether the weld is fully penetrated after welding based on the comparison result of the molten pool keyhole depth and the thickness of the workpiece to be welded includes: Comparing the keyhole depth of the molten pool with the thickness of the workpiece to be welded; If the keyhole depth of the molten pool is greater than or equal to the thickness of the workpiece to be welded, the weld is fully melted after welding; If the keyhole depth of the molten pool is less than the thickness of the workpiece to be welded, the weld is not fully melted.

14. The laser self-melting welding method according to claim 12, wherein: The determining whether the post-weld weld seam width is qualified based on a comparison result between the post-weld weld seam width and the post-weld weld seam width range includes: comparing the post-weld weld seam width with the post-weld weld seam width range; If the post-weld weld seam width is within the post-weld weld seam width range, the post-weld weld seam width is qualified; If the post-weld weld seam width is outside the post-weld weld seam width range, the post-weld weld seam width is unqualified.

15. The laser self-melting welding method according to claim 12, wherein: The judging whether the weld reinforcement after welding is qualified based on the comparison result between the weld reinforcement and the weld reinforcement range includes: comparing the weld reinforcement with the weld reinforcement range; If the weld reinforcement is within the weld reinforcement range, the weld reinforcement is qualified; If the weld reinforcement is outside the weld reinforcement range, the weld reinforcement is unqualified.

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