CN116551250A - Welding method and system - Google Patents

Abstract

The invention relates to the technical field of welding, and provides a welding method and a welding system. The method comprises the following steps: and establishing a relational database of the welding process and the welding quality. And performing test welding on the test plate based on the welding process in the relational database, and generating welding process parameters of formal welding based on the welding result. And acquiring gap parameters between at least two pieces to be welded before welding, and adjusting the pre-pressure value before welding based on comparison of the gap parameters and gap threshold values in a relational database. And welding at least two pieces to be welded by using the welding process parameters and the adjusted pre-pressure value, acquiring the expansion volume parameters of the nuggets at the welding points in the welding process, and adjusting the welding process parameters in real time based on the comparison of the expansion volume parameters and the nugget expansion threshold values in the relational database. And acquiring nugget quality parameters of nuggets at welding spots after welding is completed, and adjusting post-processing parameters after welding based on comparison of the nugget quality parameters and nugget quality thresholds in a relational database.

Description

Welding method and system

Technical Field

The invention relates to the technical field of welding, in particular to a welding method and a welding system.

Background

The body of a rail vehicle often needs to be welded during the manufacturing process, and the welding quality can affect various properties of the rail vehicle. In the welding process, welding parameters can directly influence the welding quality of workpieces after welding is finished, the welding parameters are generally set before welding, and the welding parameters cannot be adjusted in real time according to actual welding conditions in the welding process, so that the efficiency and quality of spot welding production are low.

Disclosure of Invention

The invention provides a welding method, which is used for solving the technical problem that the welding quality is low due to the fact that real-time adjustment of welding parameters cannot be carried out, realizing the monitoring of welding state and the real-time adjustment of parameters, and improving the quality of welding spots.

The invention further provides a welding system.

The invention provides a welding method, which comprises the following steps:

establishing a relational database of welding process and welding quality;

performing test welding on the test plate based on the welding process in the relational database, and generating welding process parameters of formal welding based on a welding result;

acquiring gap parameters between at least two pieces to be welded before welding, and adjusting a pre-pressure value before welding based on comparison of the gap parameters and gap threshold values in the relational database;

Welding at least two pieces to be welded according to the welding process parameters and the adjusted pre-pressure value, acquiring expansion volume parameters of nuggets at welding points in the welding process, and adjusting welding process parameters in real time based on comparison of the expansion volume parameters and nugget expansion threshold values in the relational database;

and acquiring nugget quality parameters of nuggets at welding spots after welding is finished, and adjusting post-processing parameters after welding based on comparison of the nugget quality parameters and nugget quality thresholds in the relational database.

According to the welding method provided by the invention, the test welding is carried out on the test plate based on the welding process in the relational database, and the welding process parameters of the formal welding are generated based on the welding result, which concretely comprises the following steps:

the method comprises the steps that a test board matched with a piece to be welded is identified by utilizing an identification component, the corresponding test board is grabbed to a welding platform by a grabbing component, test welding is carried out on the test board on the welding platform based on a welding process in the relational database, and performance test is carried out after the test welding is finished;

if the performance test is qualified, taking the current welding process parameters as the welding process parameters of the formal welding;

If the performance test is not qualified, the current welding process parameters are adjusted, then the test welding is continued until the performance test is qualified, and the welding process parameters of the formal welding are output.

According to the welding method provided by the invention, the performance test step is carried out after the test welding is finished, and the method specifically comprises the following steps:

continuously spot-welding three welding spots on at least three pairs of test boards respectively, tearing the last welding spot of each pair of test boards, and measuring the nugget diameter of the torn welding spot;

if the diameter of the nugget meets the requirement, the performance test is qualified;

if the diameter of the nugget does not meet the requirement, the performance test is not qualified.

According to the welding method provided by the invention, the performance test step is carried out after the test welding is finished, and the method specifically comprises the following steps:

cutting welding spots at the welding spots of the test plate along the X-axis direction and the Y-axis direction, obtaining a nugget appearance section inside the welding spots of the test plate, amplifying the nugget appearance section by a plurality of times to generate a macroscopic section, and overlapping and comparing the macroscopic section with a section digital model;

if the result of coincidence comparison meets the requirement, the performance test is qualified;

if the result of the coincidence comparison does not meet the requirement, the performance test is not qualified.

According to the welding method provided by the invention, the step of acquiring the gap parameter between at least two pieces to be welded before welding and adjusting the pre-pressure value before welding based on the comparison of the gap parameter and the gap threshold value in the relational database specifically comprises the following steps:

emitting laser to at least two workpieces to be welded at a first position, wherein the laser is reflected on the surfaces of the at least two workpieces to be welded respectively to form at least two beams of reflected light, the at least two beams of reflected light are received by a photosensitive element at a second position respectively, at least two beams of reflected light correspondingly form at least two photosensitive positions on the photosensitive element, and a gap value between the at least two workpieces to be welded is calculated based on the interval between the at least two photosensitive positions;

if the gap value is smaller than or equal to the gap threshold value in the relational database, the pre-pressure value before welding does not need to be adjusted;

and if the clearance value is larger than the clearance threshold value in the relational database, the pre-pressure value before welding is improved.

According to the welding method provided by the invention, at least two pieces to be welded are welded by the welding process parameters and the adjusted pre-pressure value, the expansion volume parameters of nuggets at welding points are obtained in the welding process, and the welding process parameters in the welding process are adjusted in real time based on the comparison of the expansion volume parameters and nugget expansion threshold values in the relational database, and the method specifically comprises the following steps:

Welding at least two pieces to be welded according to the welding process parameters and the adjusted pre-pressure value, adding an expansion displacement sensor at the welding end of a welding mechanism, acquiring the expansion volume parameters of nuggets at the welding point in real time by utilizing the expansion displacement sensor, and judging whether to adjust the welding process parameters based on the comparison of the expansion volume parameters and nugget expansion threshold values in the relational database;

if the expansion volume parameter is within the range of the nugget expansion threshold in the relational database, no adjustment of welding parameters is required;

and if the expansion volume parameter is outside the range of the nugget expansion threshold value in the relational database, adjusting at least one parameter of welding current, welding pressure, electrode pressure, welding time, cooling time, holding time and pulse number based on the relational database.

According to the welding method provided by the invention, the step of acquiring the nugget quality parameter of the nugget at the welding spot after the welding is finished and adjusting the post-processing parameter after the welding based on the comparison of the nugget quality parameter and the nugget quality threshold value in the relational database specifically comprises the following steps:

scanning the X-axis direction and the Y-axis direction of each welding spot by using a laser ranging device to form a rectangular scanning area, performing height ranging on all detection points in the rectangular scanning area, generating a three-dimensional contour by matching with the numerical value of the X-axis direction and the numerical value of the Y-axis direction, and calculating at least one parameter of pit depth and contour diameter at a nugget based on the three-dimensional contour;

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 needed;

and if the pit depth and the contour diameter are out of the ranges of the pit depth threshold and the contour diameter threshold in the relational database, performing post-processing on the welding part.

According to the welding method provided by the invention, the step of acquiring the nugget quality parameter of the nugget at the welding spot after the welding is finished and adjusting the post-processing parameter after the welding based on the comparison of the nugget quality parameter and the nugget quality threshold value in the relational database comprises the following steps:

carrying out ultrasonic scanning along a welding spot area by utilizing an ultrasonic scanning device, and calculating at least one parameter of a nugget diameter and a quality defect at the nugget based on the ultrasonic scanning result;

if the nugget diameter and the quality defect are in the range of the nugget diameter threshold and the quality defect threshold in the relational database, no post-treatment is needed;

and if the nugget diameter and the quality defect are out of the range of the nugget diameter threshold and the quality defect threshold in the relational database, performing post-treatment processing on the welding part.

According to the welding method provided by the invention, the step of acquiring the nugget quality parameter of the nugget at the welding spot after the welding is finished and adjusting the post-processing parameter after the welding based on the comparison of the nugget quality parameter and the nugget quality threshold value in the relational database comprises the following steps:

arranging a gantry crane along a welding platform, assembling a light pen measuring instrument and a laser tracker on the gantry crane, combining a piece to be welded to construct a size coordinate system, driving the light pen measuring instrument and the laser tracker to measure each welding point based on the movement of the gantry crane, and combining the measurement result with the size coordinate system to generate at least one parameter of the large span size and the form and position tolerance of each welding point;

if the large-span size and the form tolerance are within the range of the large-span size threshold and the form tolerance threshold in the relational database, no post-processing is needed;

and if the large-span size and the form and position tolerance are out of the range of the large-span size threshold and the form and position tolerance threshold in the relational database, performing post-processing on the welding part.

The present invention also provides a welding system comprising:

the database establishing unit is used for establishing a relational database of the welding process and the welding quality;

The test welding unit is electrically connected with the database establishing unit and is used for performing test welding on the test plate based on the welding process in the relational database and generating welding process parameters of formal welding based on a welding result;

the first parameter acquisition unit is electrically connected with the database establishment unit and is used for acquiring gap parameters between at least two pieces to be welded before welding and comparing the gap parameters with gap threshold values in the relational database;

the first adjusting unit is electrically connected with the first parameter obtaining unit and is used for adjusting the pre-welding pre-pressure value based on the comparison of the clearance parameter and the clearance threshold value in the relation database;

the formal welding unit is electrically connected with the database establishing unit and is used for welding at least two pieces to be welded based on the welding process parameters and the adjusted precompression value;

the second parameter acquisition unit is electrically connected with the database establishment unit and the formal welding unit and is used for acquiring the expansion volume parameter of the nugget at the welding point in the welding process and comparing the expansion volume parameter with the nugget expansion threshold value in the relational database;

The second adjusting unit is electrically connected with the database establishing unit and the formal welding unit and is used for adjusting welding parameters in welding based on comparison of the expansion volume parameters and the nugget expansion threshold values in the relational database;

the third parameter acquisition unit is electrically connected with the database establishment unit and is used for acquiring nugget quality parameters of nuggets at welding spots after welding is completed and comparing the nugget quality parameters with nugget quality thresholds in the relational database;

the third adjusting unit is electrically connected with the third parameter obtaining unit and is used for adjusting post-processing parameters after welding based on comparison of the nugget quality parameters and nugget quality thresholds in the relational database;

and the post-processing unit is electrically connected with the database establishing unit and the third adjusting unit and is used for carrying out post-welding treatment on the welding part based on the adjusted post-processing parameters.

According to the welding method provided by the embodiment of the invention, the relational database is established based on the welding process and the welding quality, the welding process parameters of the formal welding are determined according to the data in the relational database and the experimental welding result, and then the welding process parameters of each stage are adjusted in real time based on the real-time monitoring data before, during and after welding. Specifically, the pre-pressure value before welding is adjusted according to the comparison between the gap parameter monitored in real time before welding and the gap threshold value, so that the gap between the plates is ensured to meet the welding quality requirement; according to the comparison between the nugget expansion volume monitored in real time during welding and the nugget expansion threshold, each welding parameter during welding is adjusted to ensure that the welding quality requirement is met; and comparing the nugget quality parameter monitored in real time after welding with a nugget quality threshold value to judge whether to adjust the post-processing parameter so as to ensure that the welding quality requirement is met.

The welding system provided by the embodiment of the invention establishes a relational database based on the welding process and the welding quality, determines the welding process parameters of formal welding according to the data in the relational database and the experimental welding result, and 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 according to the comparison between the gap parameter monitored in real time before welding and the gap threshold value, so that the gap between the plates is ensured to meet the welding quality requirement; according to the comparison between the nugget expansion volume monitored in real time during welding and the nugget expansion threshold, each welding parameter during welding is adjusted to ensure that the welding quality requirement is met; and comparing the nugget quality parameter monitored in real time after welding with a nugget quality threshold value to judge whether to adjust the post-processing parameter so as to ensure that the welding quality requirement is met.

Drawings

In order to more clearly illustrate the invention or the technical solutions of the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the invention, and other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic flow chart of a welding method provided by the invention;

FIG. 2 is a schematic diagram of a welding system provided by the present invention;

FIG. 3 is a schematic diagram of the principle of gap measurement of two workpieces to be welded using laser provided by the invention;

fig. 4 is a schematic structural diagram of a photosensitive element provided by the present invention.

Detailed Description

Embodiments of the present invention are described in further detail below with reference to the accompanying drawings and examples. The following examples are illustrative of the invention but are not intended to limit the scope of the invention.

In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the embodiments of the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In describing embodiments of the present invention, it should be noted that, unless explicitly stated and limited otherwise, the terms "coupled," "coupled," and "connected" should be construed broadly, and may be either a fixed connection, a removable connection, or an integral connection, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium. The specific meaning of the above terms in embodiments of the present invention will be understood in detail by those of ordinary skill in the art.

In embodiments of the invention, unless expressly specified and limited otherwise, a first feature "up" or "down" on a second feature may be that the first and second features are in direct contact, or that the first and second features are in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the embodiments of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

The welding method of the present invention is described below with reference to fig. 1, including the steps of:

s100, establishing a relational database of the welding process and the welding quality.

And S200, performing test welding on the test plate based on a welding process in the relational database, and generating welding process parameters of formal welding based on a welding result.

S300, acquiring gap parameters between at least two pieces to be welded before welding, and adjusting a pre-pressure value before welding based on comparison of the gap parameters and gap threshold values in a relational database.

S400, welding at least two pieces to be welded according to the welding process parameters and the adjusted pre-pressure value, acquiring the expansion volume parameters of nuggets at the welding points in the welding process, and adjusting the welding process parameters in real time based on the comparison of the expansion volume parameters and the nugget expansion threshold values in the relational database.

S500, acquiring nugget quality parameters of nuggets at welding spots after welding, and adjusting post-processing parameters after welding based on comparison of the nugget quality parameters and nugget quality thresholds in a relational database.

In this embodiment, a relational database is established based on the welding process and the welding quality, the welding process parameters of the formal welding are determined according to the data in the relational database and the result of the experimental welding, and then the welding process parameters of each stage are adjusted in real time based on the real-time monitoring data before, during and after the welding. Specifically, the pre-pressure value before welding is adjusted according to the comparison between the gap parameter monitored in real time before welding and the gap threshold value, so that the gap between the plates is ensured to meet the welding quality requirement; according to the comparison between the nugget expansion volume monitored in real time during welding and the nugget expansion threshold, each welding parameter during welding is adjusted to ensure that the welding quality requirement is met; and comparing the nugget quality parameter monitored in real time after welding with a nugget quality threshold value to judge whether to adjust the post-processing parameter so as to ensure that the welding quality requirement is met.

After each test welding is finished, each welding process parameter of the qualified test welding is imported into the established relational database and used as a starting parameter of the test welding and/or as a comparison parameter of the follow-up formal welding in the follow-up welding process to adjust the welding process parameter in the formal welding process. After each welding is finished, the pre-pressure value corresponding to the clearance parameter before welding, the welding parameter corresponding to the expansion volume threshold of the nugget during welding and the post-processing parameter corresponding to the nugget quality of the nugget after welding are all imported into the established relational database and used for adjusting the welding process as parameters for comparison in the subsequent welding process.

The gap value between the parts to be welded can be adjusted according to the magnitude of the pre-pressure value before welding. The gap value between the workpieces to be welded has a critical influence on the quality of the outer spatter and the inner nugget of the spot welding, the problem of the appearance quality such as spot welding spatter and deformation and the problem of the inner quality of the nugget such as substandard nugget diameter or insufficient exceeding standard can be caused by overlarge gap, and the quality of the spot welding is improved by adjusting the gap value of the workpiece to be welded. When the pre-pressure value is increased, the gap value between at least two pieces to be welded can be reduced; when the pre-pressure value is reduced, the gap value between at least two pieces to be welded may be increased.

During welding, welding parameters can influence the quality of the nucleation, particularly the expansion volume parameter of the nugget, and in the welding process, whether the welding parameters need to be adjusted is judged based on the expansion volume parameter of the nugget. Specifically, the adjusted welding parameters include welding current, welding pressure, electrode pressure, welding time, cooling time, hold time, and pulse number.

After welding, it is determined whether post-treatment is required or not and the specific manner of the post-treatment based on the shape after welding.

In this embodiment, the step of establishing a relational database of welding process and welding quality specifically includes:

the method comprises the steps of establishing a relation database of pre-pressure, clearance threshold and welding quality before welding, establishing a relation database of welding parameters, nugget expansion threshold and welding quality in welding, and establishing a relation database of post-processing parameters, nugget quality threshold and welding quality after welding.

It is understood that the relational databases include pre-weld relational databases of pre-stress-gap threshold-weld quality, mid-weld relational databases of weld parameters-nugget expansion threshold-weld quality, and post-process relational databases of post-nugget quality threshold-weld quality.

The pre-pressure value and the clearance value are related, and when the pre-pressure value is increased, the clearance value between at least two pieces to be welded is reduced; when the pre-pressure value decreases, the gap value between at least two pieces 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 is indicated that the gap between the workpieces to be welded is too large at this time, and the gap between the workpieces to be welded needs to be adjusted in time to ensure the subsequent welding quality. At this time, the pre-pressure before welding is increased so that at least two pieces to be welded have larger pressure to compress the gap between the pieces to be welded, so that the gap is reduced, and when the gap parameter monitored in real time is less than or equal to 30mm, the subsequent steps are carried out under the current pre-pressure value.

The method specifically comprises the steps of performing experimental welding on a test board based on a welding process in a relational database, and generating welding process parameters of formal welding based on welding results, wherein the steps specifically comprise:

and (3) identifying the test board matched with the piece to be welded by utilizing the identification component, grabbing the corresponding test board to the welding platform by utilizing the grabbing component, performing test welding on the test board on the welding platform based on the welding process in the relational database, and performing performance test after the test welding is finished.

And if the performance test is qualified, taking the current welding process parameters as the welding process parameters of the formal welding.

If the performance test is not qualified, the current welding process parameters are adjusted, then the test welding is continued until the performance test is qualified, and the welding process parameters of the formal welding are output.

In this embodiment, the step of trial welding generally includes: identifying test boards, determining the assembly sequence of the test boards, grabbing the test boards, spot welding the test boards, grabbing the welded test boards, performing performance test and outputting results.

The test board is matched with the piece to be welded, namely the material of the test board is the same as that of the piece to be welded. Meanwhile, in order to facilitate experimental welding, the sizes of the test plates can be the same. For example, a plurality of test panels having a size of 40mmX200mm are selected, respectively. The test boards with the same size can also ensure that each test board after spot welding can be accurately placed on a tearing tester and a section cutting test bed by a robot for performance test.

The performance test step after the test welding is finished comprises the following steps:

and continuously spot-welding three welding spots on at least three pairs of test boards respectively, tearing the last welding spot of each pair of test boards, and measuring the nugget diameter of the torn welding spot.

And if the diameter of the nugget meets the requirement, the performance test is qualified.

If the diameter of the nugget does not meet the requirement, the performance test is not qualified.

In this embodiment, the step of trial welding generally includes: identifying the test board, determining the assembly sequence of the test board, grabbing the test board, spot welding the test board, grabbing the welded test board, and outputting the result.

The performance test step after the test welding is finished comprises the following steps:

cutting the welding spots along the X-axis direction and the Y-axis direction at the welding spots of the test plate to obtain a nugget appearance section inside the welding spots of the test plate, amplifying the nugget appearance section by a plurality of times to generate a macroscopic section, and overlapping and comparing the macroscopic section with a section digital model.

And if the result of the coincidence comparison meets the requirement, the performance test is qualified.

If the result of the coincidence comparison does not meet the requirement, the performance test is not qualified.

The actual macroscopic morphology of the cross section can be obtained by adopting a method of cross section sectioning test, specifically, the morphology of the molten core cross section is amplified under a microscope of 60 times, the macroscopic cross section is obtained, and whether the morphology of the molten core meets the standard requirement is rapidly judged based on the coincidence comparison of the macroscopic cross section and the cross section digital model. The method mainly judges whether the nugget diameter is in an allowable range, whether the penetration rate is in an allowable range, whether the maximum limit of the core part defect meets the requirements and the like.

In this embodiment, the step of trial welding generally includes: identifying test boards, determining the assembly sequence of the test boards, grabbing the test boards, spot welding the test boards, grabbing the welded test boards, performing a three-point tearing test, performing a cross section sectioning test, and outputting results.

The method comprises the steps of obtaining clearance parameters between at least two pieces to be welded before welding, and adjusting pre-pressure values before welding based on comparison of the clearance parameters and clearance threshold values in a relational database, and specifically comprises the following steps:

and transmitting laser to at least two pieces to be welded at a first position, respectively reflecting the laser on the surfaces of the at least two pieces to be welded to form at least two beams of reflected light, respectively receiving the at least two beams of reflected light by using a photosensitive element at a second position, correspondingly forming at least two photosensitive positions on the photosensitive element by the at least two beams of reflected light, and calculating a gap value between the at least two pieces to be welded based on the interval between the at least two photosensitive positions.

If the gap value is smaller than or equal to the gap threshold value in the relational database, the pre-pressure value before welding does not need to be adjusted.

And if the clearance value is larger than the clearance threshold value in the relational database, the pre-pressure value before welding is improved.

For two workpieces to be welded, the first workpiece 310 may be placed on a working table, and then the laser is emitted by the laser emitting unit 330, and the reflected light is received at the first photosensitive position 350 of the photosensitive element 340 after the laser is reflected on the surface of the first workpiece 310, and at this time, the point of the first photosensitive position 350 is marked. Then, the second part 320 to be welded is placed on the surface of the first part 310 to be welded, the second part 320 to be welded is attached to the first part 310 to be welded with a preset pre-pressure value, the laser is emitted by the laser emitting unit 330, the reflected light is received at the second photosensitive position 360 of the photosensitive element 340 after the laser is reflected on the surface of the second part 320 to be welded, and at this time, the point of the second photosensitive position 360 is marked. The gap value between the first workpiece 310 and the second workpiece 320 is calculated based on the distance between the first photosensitive position 350 and the second photosensitive position 360 and through the light reflection angle and the like. If the clearance value is greater than the clearance threshold, the pre-pressure value is raised and the measurement is performed again until the clearance value meets the clearance threshold.

If the two parts to be welded are transparent, the laser can pass through the parts to be welded. At this time, after the first part to be welded 310 is placed on the table, 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 is attached to the first part to be welded 310 with a preset pre-pressure value. The laser emitting unit 330 may emit laser, where the reflected light is received at the first photosensitive position 350 of the photosensitive element 340 after being reflected on the surface of the first workpiece 310, and the laser passes through the first workpiece 310 and is reflected at the position of the second workpiece 320, where the reflected light is received at the second photosensitive position 360 of the photosensitive element 340 after being reflected on the surface of the second workpiece 320, the point of the first photosensitive position 350 and the point of the second photosensitive position 360 are recorded, and the gap value between the first workpiece 310 and the second workpiece 320 is calculated based on the distance between the first photosensitive position 350 and the second photosensitive position 360 and through the light reflection angle. If the clearance value is greater than the clearance threshold, the pre-pressure value is raised and the measurement is performed again until the clearance value meets the clearance threshold.

Judging whether the pre-pressure value before welding needs to be adjusted based on the value of the clearance parameter, and reducing the clearance value between at least two pieces to be welded when the pre-pressure value is increased; when the pre-pressure value is reduced, the gap value between at least two pieces to be welded may be increased.

In one embodiment, when the gap parameter monitored in real time is 80mm and the gap threshold is within 40mm, it is indicated that the gap between the workpieces to be welded is too large at this time, and the gap between the workpieces to be welded needs to be adjusted in time to ensure the subsequent welding quality. At this time, the pre-pressure before welding is increased so that at least two pieces to be welded have larger pressure to compress the gap between the pieces to be welded, so that the gap is reduced, and when the gap parameter monitored in real time is smaller than or equal to 40mm, the subsequent steps are carried out under the current pre-pressure value.

Welding at least two pieces to be welded by using welding process parameters and adjusted pre-pressure values, acquiring expansion volume parameters of nuggets at welding points in the welding process, and adjusting the welding process parameters in real time based on comparison of the expansion volume parameters and nugget expansion threshold values in a relational database, wherein the method specifically comprises the following steps of:

And welding at least two pieces to be welded by using the welding process parameters and the adjusted pre-pressure value, adding an expansion displacement sensor at the welding end of the welding mechanism, acquiring the expansion volume parameters of the nuggets at the welding points in real time by using the expansion displacement sensor, and judging whether to adjust the welding process parameters based on the comparison of the expansion volume parameters and the nugget expansion threshold values in the relational database.

If the expansion volume parameter is within the range of the nugget expansion threshold in the relational database, no adjustment of the welding parameters is required.

And if the expansion volume parameter is outside the range of the nugget expansion threshold in the relational database, adjusting at least one parameter of welding current, welding pressure, electrode pressure, welding time, cooling time, holding time and pulse number based on the relational database.

Specifically, an expansion displacement sensor is additionally arranged on the welding tongs to monitor the fused expansion volume value in real time, and the detected expansion volume value can directly reflect the fused expansion volume parameter. Based on real-time monitoring, the data monitored by the expansion displacement sensor can be fed back to the terminal in real time, the terminal can compare the expansion volume value fed back with the nugget expansion threshold value in the relational database in the terminal, and after the comparison and judgment, the result is fed back synchronously so as to make an instruction whether the welding parameters need to be adjusted or not.

It is understood that the welding parameters include at least one of welding current, welding pressure, electrode pressure, welding time, cooling time, hold time, and pulse number. During welding, it is determined whether or not adjustment of welding current, welding pressure, electrode pressure, welding time, cooling time, holding time, and number of pulses is required based on the expansion volume parameter detected in real time. For example, based on changes in the expansion volume parameter, the welding current may be increased, the welding pressure may be increased, the electrode pressure may be increased, the welding time may be prolonged, the cooling time may be prolonged, the holding time may be prolonged, and the number of pulses may be increased.

In one embodiment, the pre-pressure may be set to 3kN, the spot welding current may be set to 9KA, the welding time may be set to 180ms, the cooling time may be set to 30ms, the number of pulses may be set to 2, the hold time may be set to 600ms, and the electrode pressure may be set to 5.6kN.

The method comprises the steps of obtaining nugget quality parameters of nuggets at welding spots after welding, and adjusting post-processing parameters after welding based on comparison of the nugget quality parameters and nugget quality thresholds in a relational database, wherein the steps specifically comprise:

Scanning the X-axis direction and the Y-axis direction of each welding spot by using a laser ranging device to form a rectangular scanning area, performing height ranging on all detection points in the rectangular scanning area, generating a three-dimensional contour by matching with the numerical value of the X-axis direction and the numerical value of the Y-axis direction, and calculating at least one parameter of pit depth and contour diameter at the nugget based on the three-dimensional contour.

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

And if the pit depth and the contour diameter are out of the ranges of the pit depth threshold value and the contour diameter threshold value in the relational database, performing post-treatment processing on the welding part.

And scanning each welding spot along the X-axis direction and the Y-axis direction to generate a rectangular scanning area of the welding spot on a horizontal plane, and performing height ranging in the rectangular scanning area, namely scanning along the Z-axis, so as to generate a three-dimensional contour at the welding spot based on the coordinate points of the X-axis, the Y-axis and the Z-axis. Based on the obtained three-dimensional profile, at least one parameter of pit depth and profile diameter at the nugget can be directly calculated. To determine the nugget quality based on at least one parameter of pit depth, profile diameter.

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

Acquiring nugget quality parameters of nuggets at welding spots after welding, and adjusting post-processing parameters after welding based on comparison of the nugget quality parameters and nugget quality thresholds in a relational database, wherein the method specifically further comprises the following steps:

and (3) carrying out ultrasonic scanning along the welding spot area by using an ultrasonic scanning device, and calculating at least one parameter of the nugget diameter and the quality defect at the nugget based on the ultrasonic scanning result.

If the nugget diameter and the mass defect are within the range of the nugget diameter threshold and the mass defect threshold in the relational database, no post-processing is needed.

And if the nugget diameter and the quality defect are out of the range of the nugget diameter threshold and the quality defect threshold in the relational database, performing post-processing on the welding part.

And directly displaying the result of the position of the welding point nugget by utilizing ultrasonic scanning, thereby calculating at least one parameter of nugget diameter and quality defect, and judging nugget quality based on the at least one parameter of nugget diameter and quality defect.

The ultrasonic scanning scans all welding spots by clamping an ultrasonic C scanning probe through a robot, scanning tracks are distributed spirally along the welding spot area, internal quality information such as nugget diameter, quality defect and the like is extracted according to the ultrasonic scanning result, and whether the internal quality of the welding spots is qualified or not is judged based on a comparison mode.

Acquiring nugget quality parameters of nuggets at welding spots after welding, and adjusting post-processing parameters after welding based on comparison of the nugget quality parameters and nugget quality thresholds in a relational database, wherein the method specifically further comprises the following steps:

arranging a gantry crane along a welding platform, assembling a light pen measuring instrument and a laser tracker on the gantry crane, specifically adopting a Leika laser tracker, combining a to-be-welded piece to construct a size coordinate system, driving the light pen measuring instrument and the laser tracker to measure each welding point based on the movement of the gantry crane, and combining the measurement result with the size coordinate system to generate at least one parameter of the large span size and the form and position tolerance of each welding point.

If the large span size and the form tolerance are within the range of the large span size threshold and the form tolerance threshold in the relational database, no post-processing is needed.

And if the large-span size and the form tolerance are out of the range of the large-span size threshold and the form tolerance threshold in the relational database, performing post-processing on the welding part.

The gantry crane is a gantry crane, and the sliding rails of the gantry crane are arranged along the length direction 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 can be understood that the portal crane spans the width direction of the welding platform, and the portal crane can drive the light pen measuring instrument and the laser tracker to monitor each welding spot in real time along the welding direction in sequence in the process of sliding along the sliding rail. And after the dimensional coordinate system of the member to be welded is combined, the large sizes of the member to be welded are all unified into one coordinate system, and the large-span sizes and form and position tolerances such as length, width, height, deflection, diagonal and flatness are generated according to the characteristics of detection results of different welding spots. And judging whether post-processing is needed or not based on comparison of the large-span size and the form tolerance with a large-span size threshold and a form tolerance threshold respectively.

The laser measurement mode is adopted, so that the measurement accuracy can reach 0.15mm, the detection time of the whole size of a single vehicle body is shortened to 1.5h (hours), and the detection efficiency is improved by more than 30%.

In this embodiment, on the one hand, the nugget mass is reacted based on the generated three-dimensional profile, on the other hand, the nugget mass is reacted based on the result of ultrasonic scanning, and on the other hand, the nugget mass is reacted by means of laser measurement or the like, and the nugget mass is reacted jointly from three aspects, so that comprehensive judgment is facilitated.

On the other hand, as shown in fig. 2, the invention also provides a welding system, which comprises a database building unit, a test welding unit, a first parameter obtaining unit, a first adjusting unit, a formal welding unit, a second parameter obtaining unit, a second adjusting unit, a third parameter obtaining unit, a third adjusting unit and a post-processing unit. The database establishing unit is used for establishing a relational database of the welding process and the welding quality. The test welding unit is electrically connected with the database establishing unit and is used for performing test welding on the test plate based on the welding process in the relational database and generating welding process parameters of formal welding based on the welding result. The first parameter acquisition unit is electrically connected with the database establishment unit and is used for acquiring gap parameters between at least two pieces to be welded before welding and comparing the gap parameters with gap thresholds in the relational database. The first adjusting unit is electrically connected with the first parameter obtaining unit and is used for adjusting the pre-pressure value before welding based on comparison of the clearance parameter and the clearance threshold value in the relation database. The formal welding unit is electrically connected with the database establishing unit and is used for welding at least two pieces to be welded based on welding process parameters and the adjusted pre-pressure value. The second parameter acquisition unit is electrically connected with the database establishment unit and the formal welding unit and is used for acquiring the expansion volume parameter of the nugget at the welding point in the welding process and comparing the expansion volume parameter with the nugget expansion threshold value in the relational database. The second adjusting unit is electrically connected with the database establishing unit and the formal welding unit and is used for adjusting welding parameters in welding based on comparison of the expansion volume parameters and the nugget expansion threshold values in the relational database. The third parameter acquisition unit is electrically connected with the database establishment unit and is used for acquiring the nugget quality parameter of the nugget at the welding spot after welding is completed and comparing the nugget quality parameter with the nugget quality threshold value in the relational database. The third adjusting unit is electrically connected with the third parameter obtaining unit and is used for adjusting post-processing parameters after welding based on comparison of the nugget quality parameters and nugget quality threshold values in the relational database. The post-processing unit is electrically connected with the database establishing unit and the third adjusting unit and is used for carrying out post-welding treatment on the welding piece based on the adjusted post-processing parameters.

In this embodiment, a relational database is established based on the welding process and the welding quality, the welding process parameters of the formal welding are determined according to the data in the relational database and the result of the experimental welding, and then the welding process parameters of each stage are adjusted in real time based on the real-time monitoring data before, during and after the welding. Specifically, the pre-pressure value before welding is adjusted according to the comparison between the gap parameter monitored in real time before welding and the gap threshold value, so that the gap between the plates is ensured to meet the welding quality requirement; according to the comparison between the nugget expansion volume monitored in real time during welding and the nugget expansion threshold, each welding parameter during welding is adjusted to ensure that the welding quality requirement is met; and comparing the nugget quality parameter monitored in real time after welding with a nugget quality threshold value to judge whether to adjust the post-processing parameter so as to ensure that the welding quality requirement is met.

The welding system further comprises a terminal, the database building unit can upload the relational database to the terminal, the first parameter obtaining unit, the second parameter obtaining unit and the third parameter obtaining unit can upload the obtained parameters to the terminal, and after the terminals are compared, the adjusting signals are sent to the first adjusting unit, the second adjusting unit and the third adjusting unit so as to facilitate subsequent adjusting measures. And starting action assignment to the test welding unit, the formal welding unit and the post-processing unit through the terminal so as to drive the test welding unit, the formal welding unit and the post-processing unit to make corresponding actions.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. A method of welding comprising the steps of:

establishing a relational database of welding process and welding quality;

performing test welding on the test plate based on the welding process in the relational database, and generating welding process parameters of formal welding based on a welding result;

acquiring gap parameters between at least two pieces to be welded before welding, and adjusting a pre-pressure value before welding based on comparison of the gap parameters and gap threshold values in the relational database;

welding at least two pieces to be welded according to the welding process parameters and the adjusted pre-pressure value, acquiring expansion volume parameters of nuggets at welding points in the welding process, and adjusting welding process parameters in real time based on comparison of the expansion volume parameters and nugget expansion threshold values in the relational database;

And acquiring nugget quality parameters of nuggets at welding spots after welding is finished, and adjusting post-processing parameters after welding based on comparison of the nugget quality parameters and nugget quality thresholds in the relational database.

2. The welding method according to claim 1, wherein the step of performing trial welding on the test board based on the welding process in the relational database and generating welding process parameters of the formal welding based on the welding result specifically comprises:

the method comprises the steps that a test board matched with a piece to be welded is identified by utilizing an identification component, the corresponding test board is grabbed to a welding platform by a grabbing component, test welding is carried out on the test board on the welding platform based on a welding process in the relational database, and performance test is carried out after the test welding is finished;

if the performance test is qualified, taking the current welding process parameters as the welding process parameters of the formal welding;

if the performance test is not qualified, the current welding process parameters are adjusted, then the test welding is continued until the performance test is qualified, and the welding process parameters of the formal welding are output.

3. The welding method according to claim 2, wherein the step of performing the performance test after the experimental welding is completed, specifically comprises:

Continuously spot-welding three welding spots on at least three pairs of test boards respectively, tearing the last welding spot of each pair of test boards, and measuring the nugget diameter of the torn welding spot;

if the diameter of the nugget meets the requirement, the performance test is qualified;

if the diameter of the nugget does not meet the requirement, the performance test is not qualified.

4. The welding method according to claim 2, wherein the step of performing the performance test after the experimental welding is completed, specifically comprises:

cutting welding spots at the welding spots of the test plate along the X-axis direction and the Y-axis direction, obtaining a nugget appearance section inside the welding spots of the test plate, amplifying the nugget appearance section by a plurality of times to generate a macroscopic section, and overlapping and comparing the macroscopic section with a section digital model;

if the result of coincidence comparison meets the requirement, the performance test is qualified;

if the result of the coincidence comparison does not meet the requirement, the performance test is not qualified.

5. The welding method according to claim 1, wherein the step of obtaining a gap parameter between at least two pieces to be welded before welding and adjusting the pre-weld pre-pressure value based on a comparison of the gap parameter with a gap threshold in the relational database, comprises:

Emitting laser to at least two workpieces to be welded at a first position, wherein the laser is reflected on the surfaces of the at least two workpieces to be welded respectively to form at least two beams of reflected light, the at least two beams of reflected light are received by a photosensitive element at a second position respectively, at least two beams of reflected light correspondingly form at least two photosensitive positions on the photosensitive element, and a gap value between the at least two workpieces to be welded is calculated based on the interval between the at least two photosensitive positions;

if the gap value is smaller than or equal to the gap threshold value in the relational database, the pre-pressure value before welding does not need to be adjusted;

and if the clearance value is larger than the clearance threshold value in the relational database, the pre-pressure value before welding is improved.

6. The welding method according to claim 1, wherein the step of welding at least two pieces to be welded with the welding process parameter and the adjusted pre-pressure value, acquiring an expansion volume parameter of a nugget at a welding point during welding, and adjusting the welding process parameter during welding in real time based on comparison of the expansion volume parameter and a nugget expansion threshold in the relational database, specifically comprises:

welding at least two pieces to be welded according to the welding process parameters and the adjusted pre-pressure value, adding an expansion displacement sensor at the welding end of a welding mechanism, acquiring the expansion volume parameters of nuggets at the welding point in real time by utilizing the expansion displacement sensor, and judging whether to adjust the welding process parameters based on the comparison of the expansion volume parameters and nugget expansion threshold values in the relational database;

If the expansion volume parameter is within the range of the nugget expansion threshold in the relational database, no adjustment of welding parameters is required;

and if the expansion volume parameter is outside the range of the nugget expansion threshold value in the relational database, adjusting at least one parameter of welding current, welding pressure, electrode pressure, welding time, cooling time, holding time and pulse number based on the relational database.

7. The welding method according to any one of claims 1 to 6, wherein the step of obtaining a nugget quality parameter of a nugget at a weld spot after completion of welding, and adjusting a post-processing parameter after welding based on comparison of the nugget quality parameter with a nugget quality threshold in the relational database, specifically comprises:

scanning the X-axis direction and the Y-axis direction of each welding spot by using a laser ranging device to form a rectangular scanning area, performing height ranging on all detection points in the rectangular scanning area, generating a three-dimensional contour by matching with the numerical value of the X-axis direction and the numerical value of the Y-axis direction, and calculating at least one parameter of pit depth and contour diameter at a nugget based on the three-dimensional contour;

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 needed;

And if the pit depth and the contour diameter are out of the ranges of the pit depth threshold and the contour diameter threshold in the relational database, performing post-processing on the welding part.

8. The welding method according to claim 7, wherein the step of obtaining a nugget quality parameter of a nugget at a weld spot after completion of welding, and adjusting a post-processing parameter after welding based on comparison of the nugget quality parameter with a nugget quality threshold in the relational database, specifically further comprises:

carrying out ultrasonic scanning along a welding spot area by utilizing an ultrasonic scanning device, and calculating at least one parameter of a nugget diameter and a quality defect at the nugget based on the ultrasonic scanning result;

if the nugget diameter and the quality defect are in the range of the nugget diameter threshold and the quality defect threshold in the relational database, no post-treatment is needed;

and if the nugget diameter and the quality defect are out of the range of the nugget diameter threshold and the quality defect threshold in the relational database, performing post-treatment processing on the welding part.

9. The welding method according to claim 8, wherein the step of obtaining a nugget quality parameter of a nugget at a weld spot after completion of welding, and adjusting a post-processing parameter after welding based on comparison of the nugget quality parameter with a nugget quality threshold in the relational database, specifically further comprises:

Arranging a gantry crane along a welding platform, assembling a light pen measuring instrument and a laser tracker on the gantry crane, combining a piece to be welded to construct a size coordinate system, driving the light pen measuring instrument and the laser tracker to measure each welding point based on the movement of the gantry crane, and combining the measurement result with the size coordinate system to generate at least one parameter of the large span size and the form and position tolerance of each welding point;

if the large-span size and the form tolerance are within the range of the large-span size threshold and the form tolerance threshold in the relational database, no post-processing is needed;

and if the large-span size and the form and position tolerance are out of the range of the large-span size threshold and the form and position tolerance threshold in the relational database, performing post-processing on the welding part.

10. A welding system, comprising:

the database establishing unit is used for establishing a relational database of the welding process and the welding quality;

the test welding unit is electrically connected with the database establishing unit and is used for performing test welding on the test plate based on the welding process in the relational database and generating welding process parameters of formal welding based on a welding result;

The first parameter acquisition unit is electrically connected with the database establishment unit and is used for acquiring gap parameters between at least two pieces to be welded before welding and comparing the gap parameters with gap threshold values in the relational database;

the first adjusting unit is electrically connected with the first parameter obtaining unit and is used for adjusting the pre-welding pre-pressure value based on the comparison of the clearance parameter and the clearance threshold value in the relation database;

the formal welding unit is electrically connected with the database establishing unit and is used for welding at least two pieces to be welded based on the welding process parameters and the adjusted precompression value;

the second parameter acquisition unit is electrically connected with the database establishment unit and the formal welding unit and is used for acquiring the expansion volume parameter of the nugget at the welding point in the welding process and comparing the expansion volume parameter with the nugget expansion threshold value in the relational database;

the second adjusting unit is electrically connected with the database establishing unit and the formal welding unit and is used for adjusting welding parameters in welding based on comparison of the expansion volume parameters and the nugget expansion threshold values in the relational database;

The third parameter acquisition unit is electrically connected with the database establishment unit and is used for acquiring nugget quality parameters of nuggets at welding spots after welding is completed and comparing the nugget quality parameters with nugget quality thresholds in the relational database;

the third adjusting unit is electrically connected with the third parameter obtaining unit and is used for adjusting post-processing parameters after welding based on comparison of the nugget quality parameters and nugget quality thresholds in the relational database;

and the post-processing unit is electrically connected with the database establishing unit and the third adjusting unit and is used for carrying out post-welding treatment on the welding part based on the adjusted post-processing parameters.