Welding method and system

Abstract

The present invention relates to the field of welding technology, and provides a welding method and system. The method comprises the following steps: establishing a relational database between welding processes and welding quality; performing test welding on a test plate based on the welding process in the relational database, and generating welding process parameters for formal welding based on the welding results; obtaining gap parameters between at least two parts to be welded before welding, and adjusting the pre-pressure value before welding based on a comparison between the gap parameters and a gap threshold value in the relational database; welding at least two parts to be welded using the welding process parameters and the adjusted pre-pressure value, obtaining an expansion volume parameter of a weld nugget at the weld point during welding, and adjusting the welding process parameters in real time based on a comparison between the expansion volume parameter and the weld nugget expansion threshold value in the relational database; obtaining a weld nugget quality parameter of the weld nugget at the weld point after welding is completed, and adjusting the post-processing parameters after welding based on a comparison between the weld nugget quality parameter and the weld nugget quality threshold value in the relational database.

Description

Technical Field

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

[0002] Rail vehicle bodies often require welding during the manufacturing process, and the quality of the welds can impact various performance characteristics of the rail vehicle. During the welding process, welding parameters directly impact the quality of the welded workpiece. These parameters are typically set before welding, but cannot be adjusted in real time based on the actual welding conditions during the welding process, resulting in low efficiency and quality in spot welding production. Summary of the Invention

[0003] The present invention provides a welding method for solving the technical problem of poor welding quality caused by failure to adjust welding parameters in real time, realizing monitoring of welding status and real-time adjustment of parameters, and improving weld quality.

[0004] The invention also provides a welding system.

[0005] The present invention provides a welding method, comprising the following steps:

[0006] Establish a database on the relationship between welding process and welding quality;

[0007] Performing test welding on the test plate based on the welding process in the relational database, and generating welding process parameters for formal welding based on the welding results;

[0008] Obtaining a gap parameter between at least two parts to be welded before welding, and adjusting a pre-welding pressure value based on a comparison between the gap parameter and a gap threshold in the relational database;

[0009] Welding at least two parts to be welded using the welding process parameters and the adjusted preload value, obtaining an expansion volume parameter of a weld nugget at a weld point during the welding process, and adjusting the welding process parameters in real time based on a comparison between the expansion volume parameter and a weld nugget expansion threshold value in the relational database;

[0010] A nugget quality parameter of a weld nugget at a weld point after welding is completed is obtained, and a post-processing parameter after welding is adjusted based on a comparison between the nugget quality parameter and a nugget quality threshold in the relational database.

[0011] According to a welding method provided by the present invention, the step of performing test welding on a test plate based on the welding process in the relational database and generating welding process parameters for formal welding based on the welding results specifically includes:

[0012] Using the recognition component to identify the test plate that matches the workpiece to be welded, using the grabbing component to grab the corresponding test plate to the welding platform, performing test welding on the test plate on the welding platform based on the welding process in the relational database, and performing performance testing after the test welding is completed;

[0013] If the performance test is qualified, the current welding process parameters will be used as the welding process parameters for formal welding;

[0014] If the performance test fails, the current welding process parameters are adjusted and the test welding is continued until the performance test passes and the welding process parameters for formal welding are output.

[0015] According to a welding method provided by the present invention, the step of performing a performance test after the test welding is completed specifically includes:

[0016] Continuously spot weld three welds on at least three test plates, tear off the last weld of each test plate, and measure the nugget diameter of the weld after tearing;

[0017] If the nugget diameter meets the requirements, the performance test is qualified;

[0018] If the nugget diameter does not meet the requirements, the performance test fails.

[0019] According to a welding method provided by the present invention, the step of performing a performance test after the test welding is completed specifically includes:

[0020] The weld point of the test plate is cut along the X-axis and Y-axis directions to obtain the cross-section of the weld nugget inside the weld point of the test plate. The cross-section of the weld nugget is magnified several times to generate a macro cross-section, and the macro cross-section is overlapped and compared with the cross-section digital model.

[0021] If the result of the overlap comparison meets the requirements, the performance test is qualified;

[0022] If the result of the overlap comparison does not meet the requirements, the performance test fails.

[0023] According to a welding method provided by the present invention, the step of obtaining a gap parameter between at least two parts to be welded before welding, and adjusting a pre-welding pressure value based on a comparison between the gap parameter and a gap threshold value in the relational database, specifically includes:

[0024] At a first position, a laser is emitted toward at least two parts to be welded. The laser is reflected from surfaces of the at least two parts to be welded and forms at least two beams of reflected light. At a second position, a photosensitive element is used to receive the at least two beams of reflected light. The at least two beams of reflected light form at least two corresponding photosensitive positions on the photosensitive element. A gap value between the at least two parts to be welded is calculated based on a distance between the at least two photosensitive positions.

[0025] If the gap value is less than or equal to the gap threshold in the relational database, there is no need to adjust the pre-welding pressure value;

[0026] If the gap value is greater than the gap threshold in the relational database, the pre-welding pressure value is increased.

[0027] According to a welding method provided by the present invention, the steps of welding at least two parts to be welded using the welding process parameters and the adjusted preload value, obtaining an expansion volume parameter of the weld nugget at the weld point during the welding process, and adjusting the welding process parameters in real time based on a comparison between the expansion volume parameter and the weld nugget expansion threshold value in the relational database, specifically include:

[0028] Welding at least two parts to be welded using the welding process parameters and the adjusted preload value, adding an expansion displacement sensor to the welding end of the welding mechanism, using the expansion displacement sensor to obtain an expansion volume parameter of the weld nugget at the weld point in real time, and determining whether to adjust the welding process parameters based on a comparison between the expansion volume parameter and a weld nugget expansion threshold value in the relational database;

[0029] If the expansion volume parameter is within the range of the nugget expansion threshold in the relational database, then there is no need to adjust the welding parameters;

[0030] If the expansion volume parameter is outside the range of the nugget expansion threshold in the relational database, at least one parameter among welding current, welding pressure, electrode pressure, welding time, cooling time, holding time and pulse number is adjusted based on the relational database.

[0031] According to a welding method provided by the present invention, the step of obtaining a nugget quality parameter of a weld nugget at a weld point after welding is completed, and adjusting a post-weld post-processing parameter based on a comparison between the nugget quality parameter and a nugget quality threshold in the relational database, specifically includes:

[0032] Scanning each weld point in the X-axis and Y-axis directions using a laser ranging device to form a rectangular scanning area, performing height ranging on all detection points within the rectangular scanning area and generating a three-dimensional profile based on the values ​​in the X-axis and Y-axis directions, and calculating at least one of the parameters of the pit depth and the profile diameter at the weld nugget based on the three-dimensional profile;

[0033] If the pit depth and the contour diameter are within the pit depth threshold and the contour diameter threshold in the relational database, no post-processing is required;

[0034] If the pit depth and the contour diameter are outside the range of the pit depth threshold and the contour diameter threshold in the relational database, post-processing is performed on the weld.

[0035] According to a welding method provided by the present invention, the step of obtaining a nugget quality parameter of a weld nugget at a weld point after welding is completed, and adjusting a post-weld post-processing parameter based on a comparison of the nugget quality parameter with a nugget quality threshold in the relational database, specifically further includes:

[0036] Performing ultrasonic scanning along the weld area using an ultrasonic scanning device, and calculating at least one parameter of a nugget diameter and a quality defect at the nugget based on the result of the ultrasonic scanning;

[0037] If the nugget diameter and quality defect are within the range of the nugget diameter threshold and quality defect threshold in the relational database, no post-processing is required;

[0038] If the nugget diameter and the quality defect are outside the range of the nugget diameter threshold and the quality defect threshold in the relational database, post-processing is performed on the weld.

[0039] According to a welding method provided by the present invention, the step of obtaining a nugget quality parameter of a weld nugget at a weld point after welding is completed, and adjusting a post-weld post-processing parameter based on a comparison of the nugget quality parameter with a nugget quality threshold in the relational database, specifically further includes:

[0040] A gantry crane is arranged along the welding platform, and a light pen measuring instrument and a laser tracker are installed on the gantry crane. A dimensional coordinate system is constructed in combination with the workpiece to be welded. The light pen measuring instrument and the laser tracker are driven by the movement of the gantry crane to measure each weld point. The measurement results are combined with the dimensional coordinate system to generate at least one parameter of the large span dimension and the form and position tolerance of each weld point;

[0041] If the large span size and the geometric tolerance are within the range of the large span size threshold and the geometric tolerance threshold in the relational database, no post-processing is required;

[0042] If the large span size and the form and position tolerance are outside the range of the large span size threshold and the form and position tolerance threshold in the relational database, the weld is post-processed.

[0043] The present invention also provides a welding system, comprising:

[0044] Database establishment unit, used to establish a database of the relationship between welding process and welding quality;

[0045] a test welding unit, electrically connected to the database establishment unit, for performing test welding on a test plate based on the welding process in the relational database, and generating welding process parameters for formal welding based on the welding results;

[0046] a first parameter acquisition unit, electrically connected to the database establishment unit, for acquiring a gap parameter between at least two to-be-welded parts before welding, and comparing the gap parameter with a gap threshold in the relational database;

[0047] a first adjustment unit, electrically connected to the first parameter acquisition unit, configured to adjust a pre-welding pressure value based on a comparison between the gap parameter and a gap threshold value in the relational database;

[0048] a formal welding unit, electrically connected to the database establishing unit, and configured to weld at least two parts to be welded based on the welding process parameters and the adjusted pre-pressure value;

[0049] a second parameter acquisition unit, electrically connected to the database establishment unit and the formal welding unit, for acquiring an expansion volume parameter of the weld nugget at the weld point during welding, and comparing the expansion volume parameter with a weld nugget expansion threshold value in the relational database;

[0050] a second adjustment unit, electrically connected to the database establishment unit and the formal welding unit, for adjusting welding parameters during welding based on a comparison of the expansion volume parameter with a nugget expansion threshold in the relational database;

[0051] a third parameter acquisition unit, electrically connected to the database establishment unit, for acquiring a nugget quality parameter of a weld nugget at a weld point after welding is completed, and comparing the nugget quality parameter with a nugget quality threshold in the relational database;

[0052] a third adjusting unit, electrically connected to the third parameter acquiring unit, for adjusting a post-weld post-processing parameter based on a comparison between the nugget quality parameter and the nugget quality threshold in the relational database;

[0053] A post-processing unit is electrically connected to the database establishing unit and the third adjusting unit, and is used to perform post-weld processing on the weldment based on the adjusted post-processing parameters.

[0054] The welding method provided by the embodiment of the present invention establishes a relational database based on the welding process and welding quality, determines the welding process parameters for formal welding based on the data in the relational database and the results of the test welding, and then adjusts the welding process parameters of each stage in real time based on the real-time monitoring data before, during and after welding. Specifically, the pre-pressure value before welding is adjusted by comparing the gap parameter monitored in real time before welding with the gap threshold, thereby ensuring that the gap between the plates meets the welding quality requirements; the various welding parameters during welding are adjusted by comparing the weld core expansion volume monitored in real time during welding with the weld core expansion threshold to ensure that the welding quality requirements are met; and the weld core quality parameters monitored in real time after welding are compared with the weld core quality threshold to determine whether to adjust the post-processing parameters to ensure that the welding quality requirements are met.

[0055] The welding system provided by the embodiment of the present invention establishes a relational database based on the welding process and welding quality, determines the welding process parameters for formal welding based on the data in the relational database and the results of the test welding, and then adjusts the welding process parameters of each stage in real time based on the real-time monitoring data before, during and after welding. Specifically, the pre-pressure value before welding is adjusted by comparing the gap parameter monitored in real time before welding with the gap threshold, thereby ensuring that the gap between the plates meets the welding quality requirements; the various welding parameters during welding are adjusted by comparing the weld core expansion volume monitored in real time during welding with the weld core expansion threshold to ensure that the welding quality requirements are met; and the weld core quality parameters monitored in real time after welding are compared with the weld core quality threshold to determine whether to adjust the post-processing parameters to ensure that the welding quality requirements are met. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0057] Figure 1 It is a schematic flow chart of the welding method provided by the present invention;

[0058] Figure 2 It is a structural schematic diagram of the welding system provided by the present invention;

[0059] Figure 3 This is a schematic diagram of the principle of measuring the gap between two parts to be welded using laser provided by the present invention;

[0060] Figure 4 It is a structural schematic diagram of the photosensitive element provided by the present invention. DETAILED DESCRIPTION

[0061] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0062] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0063] In the description of the embodiments of the present invention, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; and direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present invention based on the specific circumstances.

[0064] In the embodiments of the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," or "above" a second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," or "below" a second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0065] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0066] The following combination Figure 1 The welding method of the present invention is described, comprising the following steps:

[0067] S100. Establish a database on the relationship between welding process and welding quality.

[0068] S200: Perform test welding on the test plate based on the welding process in the relational database, and generate welding process parameters for formal welding based on the welding results.

[0069] S300 , obtaining a gap parameter between at least two parts to be welded before welding, and adjusting a pre-pressure value before welding based on a comparison between the gap parameter and a gap threshold in a relational database.

[0070] S400, welding at least two parts to be welded using welding process parameters and adjusted preload values, obtaining expansion volume parameters of the weld nugget at the weld point during the welding process, and adjusting the welding process parameters in real time based on a comparison between the expansion volume parameters and a weld nugget expansion threshold value in a relational database.

[0071] S500 , obtaining a nugget quality parameter of a weld nugget at a weld point after welding is completed, and adjusting a post-processing parameter after welding based on a comparison between the nugget quality parameter and a nugget quality threshold in a relational database.

[0072] In this embodiment, a relational database is established based on the welding process and welding quality. The welding process parameters for formal welding are determined based on the data in the relational database and the results of the test welding. Then, based on the real-time monitoring data before, during, and after welding, the welding process parameters of each stage are adjusted in real time. Specifically, the pre-welding pressure value is adjusted based on the gap parameter monitored in real time before welding and the gap threshold, thereby ensuring that the gap between the plates meets the welding quality requirements; the various welding parameters during welding are adjusted based on the weld nugget expansion volume monitored in real time during welding and the weld nugget expansion threshold to ensure that the welding quality requirements are met; and the weld nugget quality parameters monitored in real time after welding are compared with the weld nugget quality threshold to determine whether to adjust the post-processing parameters to ensure that the welding quality requirements are met.

[0073] After each test weld is completed, the various welding process parameters of the qualified test welds are imported into the established relational database and used as starting parameters for the test welds and / or as reference parameters for the subsequent formal welds to adjust the welding process parameters during the formal welds. After each weld is completed, the pre-pressure value corresponding to the gap parameter before welding, the welding parameters corresponding to the expansion volume threshold of the weld nugget during welding, and the post-processing parameters corresponding to the weld nugget quality after welding are all imported into the established relational database and used as reference parameters to adjust the welding process during the subsequent welding process.

[0074] Before welding, the gap between the parts to be welded can be adjusted based on the preload pressure. The gap between the parts to be welded has a crucial impact on the external spatter and internal weld nugget quality of the spot weld. Excessive gaps can lead to external quality issues such as spatter and deformation, as well as internal quality issues such as substandard or excessive weld nugget diameters. Adjusting the gap between the parts to be welded improves spot welding quality. Increasing the preload pressure reduces the gap between the at least two parts to be welded, while decreasing the preload pressure increases the gap between the at least two parts to be welded.

[0075] During welding, welding parameters affect the quality of nucleation, particularly the expansion volume of the weld nugget. This expansion volume is used to determine whether welding parameters need adjustment. Specifically, the parameters to be adjusted include welding current, welding pressure, electrode pressure, welding time, cooling time, hold time, and pulse count.

[0076] After welding, the need for post-processing and the specific method of post-processing will be determined based on the post-weld shape.

[0077] In this embodiment, the steps of establishing a database of the relationship between welding process and welding quality specifically include:

[0078] Establish a database of the relationship between the pre-pressure, gap threshold and welding quality before welding, establish a database of the relationship between welding parameters, weld core expansion threshold and welding quality during welding, and establish a database of the relationship between post-processing parameters, weld core quality threshold and welding quality after welding.

[0079] It can be understood that the relational database includes a pre-weld relational database formed by pre-pressure-gap threshold-welding quality, a mid-weld relational database formed by welding parameters-weld core expansion threshold-welding quality, and a post-weld relational database formed by post-processing parameters-weld core quality threshold-welding quality.

[0080] The pre-pressure value and the gap value are interrelated. When the pre-pressure value increases, the gap value between at least two parts to be welded decreases; when the pre-pressure value decreases, the gap value between at least two parts to be welded increases. For example, when the gap parameter monitored in real time is 50mm (millimeter) and the gap threshold is within 30mm, it means that the gap between the parts to be welded is too large at this time, and the gap between the parts to be welded needs to be adjusted in time to ensure the subsequent welding quality. At this time, by increasing the pre-pressure before welding, a greater pressure is applied between at least two parts to be welded to compress the gap between the parts to be welded so that the gap is reduced. When the gap parameter monitored in real time is less than or equal to 30mm, the subsequent steps are carried out at the current pre-pressure value.

[0081] The steps of performing test welding on a test plate based on the welding process in the relational database and generating welding process parameters for formal welding based on the welding results specifically include:

[0082] The identification component is used to identify the test plate that matches the workpiece to be welded, and the corresponding test plate is grabbed by the grabbing component to the welding platform. The test plate is test welded on the welding platform based on the welding process in the relational database, and the performance test is performed after the test welding is completed.

[0083] If the performance test is qualified, the current welding process parameters will be used as the welding process parameters for formal welding.

[0084] If the performance test fails, the current welding process parameters are adjusted and the test welding is continued until the performance test passes and the welding process parameters for formal welding are output.

[0085] In this embodiment, the test welding steps generally include: identifying the test plate - clarifying the assembly order of the test plate - grabbing the test plate - spot welding the test plate - grabbing the welded test plate - performance testing - outputting the results.

[0086] The test plates should be matched to the workpiece being welded, meaning they should be made of the same material. To facilitate test welding, the test plates can be of the same size. For example, multiple test plates measuring 40mm x 200mm can be selected. Using the same test plate size also ensures that each spot-welded test plate can be accurately placed by the robot into the tear tester and cross-section test bench for performance testing.

[0087] The steps for performance testing after test welding are as follows:

[0088] Spot weld three welds continuously on at least three test plates, tear off the last weld of each test plate, and measure the diameter of the nugget of the weld after tearing.

[0089] If the nugget diameter meets the requirements, the performance test is qualified.

[0090] If the nugget diameter does not meet the requirements, the performance test fails.

[0091] In this embodiment, the test welding steps generally include: identifying the test plate - clarifying the assembly order of the test plate - grabbing the test plate - spot welding the test plate - grabbing the welded test plate - three-point tear test - outputting the results.

[0092] The steps for performance testing after test welding are as follows:

[0093] The weld spot of the test plate is cut along the X-axis and Y-axis directions to obtain the weld nugget morphology cross section inside the weld spot of the test plate. The weld nugget morphology cross section is magnified several times to generate a macro cross section, and the macro cross section is overlapped and compared with the cross section digital model.

[0094] If the result of the overlap comparison meets the requirements, the performance test is qualified.

[0095] If the result of the overlap comparison does not meet the requirements, the performance test fails.

[0096] The cross-section test method can be used to obtain the actual macroscopic morphology of the cross section. Specifically, the cross-section of the nugget is magnified under a microscope at 60x magnification to obtain a macroscopic cross section. Based on the overlap and comparison of the macroscopic cross section with the cross-section digital model, it is quickly determined whether the nugget morphology meets the standard requirements. Among them, the main judgments are whether the nugget diameter is within the allowable range, whether the penetration rate is within the allowable range, and whether the maximum limit of core defects meets the requirements.

[0097] In this embodiment, the test welding steps generally include: identifying the test plate - clarifying the assembly order of the test plate - grabbing the test plate - spot welding the test plate - grabbing the welded test plate - three-point tear test - cross-section cutting test - outputting the results.

[0098] The steps of obtaining a gap parameter between at least two parts to be welded before welding, and adjusting a pre-welding pressure value based on a comparison between the gap parameter and a gap threshold in a relational database, specifically include:

[0099] At a first position, a laser is emitted toward at least two parts to be welded. The laser is reflected on the surfaces of the at least two parts to be welded and forms at least two beams of reflected light. At a second position, a photosensitive element is used to receive the at least two beams of reflected light. The at least two beams of reflected light form at least two corresponding photosensitive positions on the photosensitive element. The gap value between the at least two parts to be welded is calculated based on the distance between the at least two photosensitive positions.

[0100] If the gap value is less than or equal to the gap threshold in the relational database, there is no need to adjust the pre-welding pressure value.

[0101] If the gap value is greater than the gap threshold in the relational database, the pre-welding pressure value is increased.

[0102] For example, for two parts to be welded, the first part to be welded 310 can be placed on a work surface. Laser emitting unit 330 then emits a laser. The laser light reflects off the surface of first part 310, and the reflected light is received at first photosensitive position 350 of photosensitive element 340. The location of first photosensitive position 350 is marked. Next, second part 320 can be placed on the surface of first part 310, and the two parts can be brought into contact with each other using a predetermined preload. Laser emitting unit 330 then emits a laser light. The laser light reflects off the surface of second part 320, and the reflected light is received at second photosensitive position 360 of photosensitive element 340. The location of second photosensitive position 360 is marked. Based on the distance between first photosensitive position 350 and second photosensitive position 360, and taking into account the light reflection angle, the gap between first and second parts to be welded 310 and 320 can be calculated. If the gap value is greater than the gap threshold, the preload value is increased and the above measurement is performed again until the gap value meets the gap threshold.

[0103] If the two parts to be welded are transparent, the laser can pass through them. In this case, after placing the first part to be welded 310 on the work surface, the second part to be welded 320 is directly placed on the first part to be welded 310, and the second part to be welded 320 and the first part to be welded 310 are brought into contact with each other using a set preload value. Laser light can be emitted by the laser emitting unit 330. After reflecting from the surface of the first part to be welded 310, the reflected light is received by the first photosensitive position 350 of the photosensitive element 340. The laser light passes through the first part to be welded 310 and reflects at the position of the second part to be welded 320. After reflecting from the surface of the second part to be welded 320, the reflected light is received by the second photosensitive position 360 of the photosensitive element 340. The positions of the first photosensitive position 350 and the second photosensitive position 360 are recorded. Based on the distance between the first photosensitive position 350 and the second photosensitive position 360 and the light reflection angle, the gap value between the first part to be welded 310 and the second part to be welded 320 is calculated. If the gap value is greater than the gap threshold, the preload value is increased and the above measurement is performed again until the gap value meets the gap threshold.

[0104] Whether the pre-welding pressure value needs to be adjusted is determined based on the numerical value of the gap parameter. When the pre-welding pressure value increases, the gap value between at least two parts to be welded can be reduced; when the pre-welding pressure value decreases, the gap value between at least two parts to be welded can be increased.

[0105] In one embodiment, when the real-time monitored gap parameter is 80 mm and the gap threshold is within 40 mm, it indicates that the gap between the welded parts is too large and needs to be adjusted promptly to ensure subsequent welding quality. In this case, the pre-weld pressure is increased to create a greater pressure between at least two welded parts, thereby compressing the gap between the welded parts and reducing the gap. When the real-time monitored gap parameter is less than or equal to 40 mm, the current pre-weld pressure is maintained for subsequent steps.

[0106] The steps of welding at least two parts to be welded using welding process parameters and an adjusted preload value, obtaining an expansion volume parameter of a weld nugget at a weld point during welding, and adjusting the welding process parameters in real time based on a comparison between the expansion volume parameter and a weld nugget expansion threshold value in a relational database, specifically comprising:

[0107] At least two parts to be welded are welded using welding process parameters and adjusted preload values. An expansion displacement sensor is added to the welding end of the welding mechanism. The expansion volume parameter of the weld nugget at the weld point is obtained in real time using the expansion displacement sensor. Based on the comparison between the expansion volume parameter and the weld nugget expansion threshold value in the relational database, it is determined whether the welding process parameters should be adjusted.

[0108] If the expansion volume parameter is within the range of the nugget expansion threshold in the relational database, there is no need to adjust the welding parameters.

[0109] If the expansion volume parameter is outside the range of the nugget expansion threshold in the relational database, at least one parameter of welding current, welding pressure, electrode pressure, welding time, cooling time, holding time and pulse number is adjusted based on the relational database.

[0110] Specifically, an expansion displacement sensor is added to the welding tongs to monitor the fusion expansion volume in real time. This detected expansion volume directly reflects the fusion expansion volume parameters. Based on real-time monitoring, the data detected by the expansion displacement sensor is fed back to the terminal in real time. The terminal compares the fed-back expansion volume value with the weld nugget expansion threshold stored in an internal relational database. After the comparison, the result is synchronously fed back to determine whether the welding parameters need to be adjusted.

[0111] It is understood that welding parameters include at least one of welding current, welding pressure, electrode pressure, welding time, cooling time, hold time, and pulse number. During welding, the need to adjust the welding current, welding pressure, electrode pressure, welding time, cooling time, hold time, and pulse number is determined based on the real-time detected expansion volume parameter. For example, based on changes in the expansion volume parameter, the welding current, welding pressure, electrode pressure, welding time, cooling time, hold time, and pulse number may be increased, or the welding time, cooling time, hold time, and pulse number may be increased.

[0112] In one embodiment, the pre-pressure can be set to 3kN (kilonewtons), the spot welding current can be set to 9KA (kiloamperes), the welding time can be set to 180ms (milliseconds), the cooling time can be set to 30ms, the number of pulses can be set to 2, the holding time can be set to 600ms, and the electrode pressure can be set to 5.6kN.

[0113] The steps of obtaining a nugget quality parameter of a weld nugget at a weld point after welding is completed, and adjusting a post-processing parameter after welding based on a comparison between the nugget quality parameter and a nugget quality threshold in a relational database, specifically comprising:

[0114] A laser ranging device is used to scan each weld in the X-axis and Y-axis directions to form a rectangular scanning area. The height of all detection points in the rectangular scanning area is measured and a three-dimensional profile is generated in combination with the values ​​in the X-axis and Y-axis directions. Based on the three-dimensional profile, at least one parameter of the pit depth and profile diameter at the weld nugget is calculated.

[0115] If the pit depth and the contour diameter are within the range of the pit depth threshold and the contour diameter threshold in the relational database, no post-processing is required.

[0116] If the pit depth and the contour diameter are outside the range of the pit depth threshold and the contour diameter threshold in the relational database, the weld is post-processed.

[0117] Scanning each weld along the X and Y axes creates a horizontal rectangular scan area for the weld. Height measurement is then performed within the rectangular scan area, i.e., scanning along the Z axis. This generates a three-dimensional profile of the weld based on the X, Y, and Z coordinates. Based on the resulting three-dimensional profile, at least one of the pit depth and profile diameter of the weld nugget can be directly calculated. The quality of the weld nugget can then be determined based on at least one of these parameters.

[0118] The X-axis direction may be the length direction of the welding platform, the Y-axis direction may be the width direction of the welding platform, and the Z-axis direction may be the height direction of the welding platform.

[0119] The steps of obtaining a nugget quality parameter of the weld nugget at the weld point after welding is completed, and adjusting a post-weld post-processing parameter based on the comparison of the nugget quality parameter with a nugget quality threshold in a relational database, specifically further include:

[0120] An ultrasonic scanning device is used to perform ultrasonic scanning along the weld area, and at least one parameter of a nugget diameter and a quality defect at the nugget is calculated based on the result of the ultrasonic scanning.

[0121] If the nugget diameter and the quality defect are within the range of the nugget diameter threshold and the quality defect threshold in the relational database, no post-processing is required.

[0122] If the nugget diameter and the quality defect are outside the range of the nugget diameter threshold and the quality defect threshold in the relational database, the weld is post-processed.

[0123] Ultrasonic scanning is used to directly display the position of the weld nugget, thereby calculating at least one parameter of the weld nugget diameter and quality defect, so as to judge the weld nugget quality based on at least one parameter of the weld nugget diameter and quality defect.

[0124] Ultrasonic scanning uses a robot to clamp an ultrasonic C-scan probe to scan each weld point. The scanning track is distributed in a spiral along the weld point area. Based on the results of the ultrasonic scanning, internal quality information such as the weld core diameter and quality defects is extracted, and the internal quality of the weld point is judged based on comparison.

[0125] The steps of obtaining a nugget quality parameter of the weld nugget at the weld point after welding is completed, and adjusting a post-weld post-processing parameter based on the comparison of the nugget quality parameter with a nugget quality threshold in a relational database, specifically further include:

[0126] A gantry crane is arranged along the welding platform, and a light pen measuring instrument and a laser tracker are installed on the gantry crane. Specifically, a Leica laser tracker can be used, and a dimensional coordinate system is constructed in combination with the parts to be welded. The light pen measuring instrument and the laser tracker are driven by the movement of the gantry crane to measure each weld point. The measurement results combined with the dimensional coordinate system can generate at least one parameter of the large-span size and form and position tolerance of each weld point.

[0127] If the large span size and geometric tolerance are within the range of the large span size threshold and geometric tolerance threshold in the relational database, no post-processing is required.

[0128] If the large span size and the form and position tolerance are outside the range of the large span size threshold and the form and position tolerance threshold in the relational database, the weld is post-processed.

[0129] A gantry crane is a type of gantry crane. The sliding rails of the gantry crane are arranged along the length of the welding platform, so that the arrangement direction of the sliding rails of the gantry crane is the same as the welding direction. It is understandable that the gantry crane spans the width of the welding platform. As the gantry crane slides along the sliding rails, it can drive the light pen measuring instrument and laser tracker to monitor each weld point in real time along the welding direction. After combining the coordinate system of the component size of the welded parts, all the large dimensions of the welded parts are unified into one coordinate system. Based on the characteristics of the inspection results of different weld points, large span dimensions and form and position tolerances such as length, width, height, deflection, diagonal and flatness are generated. Based on the comparison of the large span dimensions and form and position tolerances with the large span dimension threshold and form and position tolerance threshold, it is determined whether post-processing is required.

[0130] The use of laser measurement can achieve a measurement accuracy of 0.15mm, shorten the full-size inspection time of a single vehicle body to 1.5 hours, and improve the inspection efficiency by more than 30%.

[0131] In this embodiment, the quality of the weld nugget is reflected based on the generated three-dimensional contour on the one hand, the quality of the weld nugget is reflected based on the result of ultrasonic scanning on the other hand, and the quality of the weld nugget is reflected by laser measurement and the like on the third hand. The quality of the weld nugget is reflected from these three aspects together to facilitate comprehensive judgment.

[0132] On the other hand, Figure 2As shown, the present invention also provides a welding system, comprising a database establishment unit, a test welding unit, a first parameter acquisition unit, a first adjustment unit, a formal welding unit, a second parameter acquisition unit, a second adjustment unit, a third parameter acquisition unit, a third adjustment unit, and a post-processing unit. The database establishment unit is configured to establish a relational database between welding processes and welding quality. The test welding unit is electrically connected to the database establishment unit and configured to perform test welding on a test plate based on the welding process in the relational database and to generate welding process parameters for formal welding based on the welding results. The first parameter acquisition unit is electrically connected to the database establishment unit and configured to acquire gap parameters between at least two parts to be welded before welding and compare the gap parameters with gap thresholds in the relational database. The first adjustment unit is electrically connected to the first parameter acquisition unit and configured to adjust a pre-weld pressure value based on a comparison of the gap parameters with the gap thresholds in the relational database. The formal welding unit is electrically connected to the database establishment unit and configured to weld the at least two parts to be welded based on the welding process parameters and the adjusted pre-weld pressure value. The second parameter acquisition unit is electrically connected to the database establishment unit and the formal welding unit and configured to acquire an expansion volume parameter of the weld nugget at the weld point during welding and compare the expansion volume parameter with the weld nugget expansion threshold in the relational database. The second adjustment unit is electrically connected to the database establishment unit and the main welding unit, and is configured to adjust welding parameters during welding based on a comparison of the expansion volume parameter with the nugget expansion threshold in the relational database. The third parameter acquisition unit is electrically connected to the database establishment unit, and is configured to acquire nugget quality parameters of the nugget at the weld point after welding is completed, and compare the nugget quality parameters with the nugget quality threshold in the relational database. The third adjustment unit is electrically connected to the third parameter acquisition unit, and is configured to adjust post-weld post-processing parameters based on a comparison of the nugget quality parameters with the nugget quality threshold in the relational database. The post-processing unit is electrically connected to the database establishment unit and the third adjustment unit, and is configured to perform post-weld processing on the welded part based on the adjusted post-processing parameters.

[0133] In this embodiment, a relational database is established based on the welding process and welding quality. The welding process parameters for formal welding are determined based on the data in the relational database and the results of the test welding. Then, based on the real-time monitoring data before, during, and after welding, the welding process parameters of each stage are adjusted in real time. Specifically, the pre-welding pressure value is adjusted based on the gap parameter monitored in real time before welding and the gap threshold, thereby ensuring that the gap between the plates meets the welding quality requirements; the various welding parameters during welding are adjusted based on the weld nugget expansion volume monitored in real time during welding and the weld nugget expansion threshold to ensure that the welding quality requirements are met; and the weld nugget quality parameters monitored in real time after welding are compared with the weld nugget quality threshold to determine whether to adjust the post-processing parameters to ensure that the welding quality requirements are met.

[0134] The welding system may further include a terminal. The database building unit may upload the relational database to the terminal. The first parameter acquisition unit, the second parameter acquisition unit, and the third parameter acquisition unit may upload the acquired parameters to the terminal. After comparison at the terminal, the adjustment signal is sent to the first adjustment unit, the second adjustment unit, and the third adjustment unit to facilitate subsequent adjustment measures. The terminal also triggers action designations to the test welding unit, the formal welding unit, and the post-processing unit to drive the test welding unit, the formal welding unit, and the post-processing unit to perform corresponding actions.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A welding method, characterized in that: The steps include: Establish a relationship database between welding process and welding quality, including a pre-welding relationship database formed by pre-pressure-gap threshold-welding quality, a mid-welding relationship database formed by welding parameters-nugget expansion threshold-welding quality, and a post-welding relationship database formed by post-processing parameters-nugget quality threshold-welding quality; Performing test welding on the test plate based on the welding process in the relational database, and generating welding process parameters for formal welding based on the welding results; Obtaining a gap parameter between at least two parts to be welded before welding, and adjusting a pre-welding pressure value based on a comparison between the gap parameter and a gap threshold in the relational database; Welding at least two parts to be welded using the welding process parameters and the adjusted preload value, obtaining an expansion volume parameter of a weld nugget at a weld point during the welding process, and adjusting the welding process parameters in real time based on a comparison between the expansion volume parameter and a weld nugget expansion threshold value in the relational database; A nugget quality parameter of a weld nugget at a weld point after welding is completed is obtained, and a post-processing parameter after welding is adjusted based on a comparison between the nugget quality parameter and a nugget quality threshold in the relational database.

2. The welding method according to claim 1, characterized in that The step of performing test welding on the test plate based on the welding process in the relational database and generating welding process parameters for formal welding based on the welding results specifically includes: Using the recognition component to identify the test plate that matches the workpiece to be welded, using the grabbing component to grab the corresponding test plate to the welding platform, performing test welding on the test plate on the welding platform based on the welding process in the relational database, and performing performance testing after the test welding is completed; If the performance test is qualified, the current welding process parameters will be used as the welding process parameters for formal welding; If the performance test fails, the current welding process parameters are adjusted and the test welding is continued until the performance test passes and the welding process parameters for formal welding are output.

3. The welding method according to claim 2, characterized in that The steps of performing performance testing after the test welding is completed specifically include: Continuously spot weld three welds on at least three test plates, tear off the last weld of each test plate, and measure the nugget diameter of the weld after tearing; If the nugget diameter meets the requirements, the performance test is qualified; If the nugget diameter does not meet the requirements, the performance test fails.

4. The welding method according to claim 2, characterized in that The steps of performing performance testing after the test welding is completed specifically include: The weld point of the test plate is cut along the X-axis and Y-axis directions to obtain the cross-section of the weld nugget inside the weld point of the test plate. The cross-section of the weld nugget is magnified several times to generate a macro cross-section, and the macro cross-section is overlapped and compared with the cross-section digital model. If the result of the overlap comparison meets the requirements, the performance test is qualified; If the result of the overlap comparison does not meet the requirements, the performance test fails.

5. The welding method according to claim 1, wherein: The step of obtaining a gap parameter between at least two parts to be welded before welding, and adjusting a pre-welding pressure value based on a comparison between the gap parameter and a gap threshold in the relational database, specifically includes: At a first position, a laser is emitted toward at least two parts to be welded. The laser is reflected from surfaces of the at least two parts to be welded and forms at least two beams of reflected light. At a second position, a photosensitive element is used to receive the at least two beams of reflected light. The at least two beams of reflected light form at least two corresponding photosensitive positions on the photosensitive element. A gap value between the at least two parts to be welded is calculated based on a distance between the at least two photosensitive positions. If the gap value is less than or equal to the gap threshold in the relational database, there is no need to adjust the pre-welding pressure value; If the gap value is greater than the gap threshold in the relational database, the pre-welding pressure value is increased.

6. The welding method according to claim 1, characterized in that The step of welding at least two parts to be welded using the welding process parameters and the adjusted preload value, obtaining an expansion volume parameter of the weld nugget at the weld point during the welding process, and adjusting the welding process parameters in real time based on a comparison between the expansion volume parameter and the weld nugget expansion threshold value in the relational database, specifically includes: Welding at least two parts to be welded using the welding process parameters and the adjusted preload value, adding an expansion displacement sensor to the welding end of the welding mechanism, using the expansion displacement sensor to obtain an expansion volume parameter of the weld nugget at the weld point in real time, and determining whether to adjust the welding process parameters based on a comparison between the expansion volume parameter and a weld nugget expansion threshold value in the relational database; If the expansion volume parameter is within the range of the nugget expansion threshold in the relational database, then there is no need to adjust the welding parameters; If the expansion volume parameter is outside the range of the nugget expansion threshold in the relational database, at least one parameter among welding current, welding pressure, electrode pressure, welding time, cooling time, holding time and pulse number is adjusted based on the relational database.

7. The welding method according to any one of claims 1 to 6, characterized in that: The step of obtaining a nugget quality parameter of the weld nugget at the weld point after welding is completed, and adjusting a post-weld post-processing parameter based on a comparison between the nugget quality parameter and a nugget quality threshold in the relational database specifically includes: Scanning each weld point in the X-axis and Y-axis directions using a laser ranging device to form a rectangular scanning area, performing height ranging on all detection points within the rectangular scanning area and generating a three-dimensional profile based on the values ​​in the X-axis and Y-axis directions, and calculating at least one of the parameters of the pit depth and the profile diameter at the weld nugget based on the three-dimensional profile; If the pit depth and the contour diameter are within the pit depth threshold and the contour diameter threshold in the relational database, no post-processing is required; If the pit depth and the contour diameter are outside the range of the pit depth threshold and the contour diameter threshold in the relational database, post-processing is performed on the weld.

8. The welding method according to claim 7, characterized in that: The step of obtaining a nugget quality parameter of the weld nugget at the weld point after welding is completed, and adjusting a post-weld post-processing parameter based on a comparison between the nugget quality parameter and a nugget quality threshold in the relational database, specifically further includes: Performing ultrasonic scanning along the weld area using an ultrasonic scanning device, and calculating at least one parameter of a nugget diameter and a quality defect at the nugget based on the result of the ultrasonic scanning; If the nugget diameter and quality defect are within the range of the nugget diameter threshold and quality defect threshold in the relational database, no post-processing is required; If the nugget diameter and the quality defect are outside the range of the nugget diameter threshold and the quality defect threshold in the relational database, post-processing is performed on the weld.

9. The welding method according to claim 8, characterized in that: The step of obtaining a nugget quality parameter of the weld nugget at the weld point after welding is completed, and adjusting a post-weld post-processing parameter based on a comparison between the nugget quality parameter and a nugget quality threshold in the relational database, specifically further includes: A gantry crane is arranged along the welding platform, and a light pen measuring instrument and a laser tracker are installed on the gantry crane. A dimensional coordinate system is constructed in combination with the workpiece to be welded. The light pen measuring instrument and the laser tracker are driven by the movement of the gantry crane to measure each weld point. The measurement results are combined with the dimensional coordinate system to generate at least one parameter of the large span dimension and the form and position tolerance of each weld point; If the large span size and the geometric tolerance are within the range of the large span size threshold and the geometric tolerance threshold in the relational database, no post-processing is required; If the large span size and the form and position tolerance are outside the range of the large span size threshold and the form and position tolerance threshold in the relational database, the weld is post-processed.

10. A welding system, characterized in that: include: a database establishment unit for establishing a relational database between welding process and welding quality, the relational database including a pre-welding relational database formed by pre-pressure, gap threshold, and welding quality, a mid-welding relational database formed by welding parameters, nugget expansion threshold, and welding quality, and a post-welding relational database formed by post-processing parameters, nugget quality threshold, and welding quality; a test welding unit, electrically connected to the database establishment unit, for performing test welding on a test plate based on the welding process in the relational database, and generating welding process parameters for formal welding based on the welding results; a first parameter acquisition unit, electrically connected to the database establishment unit, for acquiring a gap parameter between at least two to-be-welded parts before welding, and comparing the gap parameter with a gap threshold in the relational database; a first adjustment unit, electrically connected to the first parameter acquisition unit, configured to adjust a pre-welding pressure value based on a comparison between the gap parameter and a gap threshold value in the relational database; a formal welding unit, electrically connected to the database establishing unit, and configured to weld at least two parts to be welded based on the welding process parameters and the adjusted pre-pressure value; a second parameter acquisition unit, electrically connected to the database establishment unit and the formal welding unit, for acquiring an expansion volume parameter of the weld nugget at the weld point during welding, and comparing the expansion volume parameter with a weld nugget expansion threshold value in the relational database; a second adjustment unit, electrically connected to the database establishment unit and the formal welding unit, for adjusting welding parameters during welding based on a comparison of the expansion volume parameter with a nugget expansion threshold in the relational database; a third parameter acquisition unit, electrically connected to the database establishment unit, for acquiring a nugget quality parameter of a weld nugget at a weld point after welding is completed, and comparing the nugget quality parameter with a nugget quality threshold in the relational database; a third adjusting unit, electrically connected to the third parameter acquiring unit, for adjusting a post-weld post-processing parameter based on a comparison between the nugget quality parameter and the nugget quality threshold in the relational database; A post-processing unit is electrically connected to the database establishing unit and the third adjusting unit, and is used to perform post-weld processing on the weldment based on the adjusted post-processing parameters.

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