Metal table and chair frame multi-point synchronous welding anti-deformation clamping method and system

Abstract

The application discloses a metal table and chair frame multi-point synchronous welding anti-deformation clamping method and system, and relates to the technical field of table and chair production. The method first constructs a multi-point adaptive pre-positioning matrix, divides a stress area, and determines the corresponding relationship of positioning points, clamping points and welding points; then, multi-point synchronous flexible pre-clamping is implemented on a main load-bearing component, so that the geometric precision of the component is ensured and stress concentration is avoided; a timing-clamping force linkage model is established based on thermal expansion and welding heat input characteristics, and deformation is reduced by using symmetric and cross welding timing; during welding, the parameters of each welding point are synchronously controlled, stress and strain are monitored in real time through a sensor, and clamping force is dynamically adjusted to offset thermal deformation; after welding, the clamping force is unloaded according to a symmetric gradient, and natural cooling is performed to shape. The application can realize collaborative control of welding and clamping, effectively suppresses the welding thermal deformation of the frame, improves the size precision and structural stability of products, and is suitable for automatic welding production of various metal table and chair frames.

Description

Technical Field

[0001] This invention belongs to the field of table and chair manufacturing technology, and in particular relates to a method and system for multi-point synchronous welding and anti-deformation clamping of metal table and chair frames. Background Technology

[0002] Metal table and chair frames are mostly constructed by splicing and welding steel pipes, steel plates, and other components. The welding quality and geometric accuracy directly determine the load-bearing stability and service life of the tables and chairs. The core technical problem with existing technologies in the multi-point synchronous welding and anti-deformation clamping process of metal table and chair frames is the lack of a dynamic linkage mechanism between welding sequence and clamping force. This prevents real-time adjustment of the clamping state based on thermal deformation during welding, resulting in ineffective countermeasures against welding thermal deformation. Ultimately, this leads to dimensional deviations and structural deformation in the metal table and chair frames, making it difficult to meet the demands of high-precision production. Summary of the Invention

[0003] The purpose of this invention is to provide a method and system for multi-point synchronous welding and anti-deformation clamping of metal table and chair frames, so as to solve the problems mentioned in the background art.

[0004] In view of this, the present invention provides a method for multi-point synchronous welding and anti-deformation clamping of metal table and chair frames, comprising the following steps:

[0005] S1. Based on the component cross-section, weld distribution and stress characteristics of the metal table and chair frame, construct a multi-point adaptive pre-positioning matrix to determine the correspondence between the reference positioning point, clamping action point and weld point of each component.

[0006] S2. Based on the pre-positioning matrix, multi-point synchronous flexible pre-clamping is implemented on the main load-bearing components of the table and chair frame to form initial positioning constraints in three-dimensional space.

[0007] S3. Based on the component's thermal expansion coefficient and welding heat input characteristics, establish a welding timing-clamping force linkage model to determine the timing nodes of synchronous welding and the dynamic force values ​​of each clamping point.

[0008] S4. Perform synchronous arc welding of multiple welding points according to the linkage model, and synchronously control the welding current, wire feeding speed and welding time of each welding point to make the heat input of each welding point uniformly matched.

[0009] S5. During the welding process, stress and strain data of each clamping point are collected in real time, and the clamping force and displacement of each clamping point are dynamically adjusted to counteract welding thermal deformation in real time.

[0010] S6. After welding is completed, release the clamping force gradually in the order of symmetrical relaxation and gradient unloading, so that the frame can cool and solidify naturally without forced constraints.

[0011] In a further embodiment of the present invention, step S1 includes:

[0012] S11. Measure the cross-sectional parameters and weld locations of the crossbeams, longitudinal beams, and columns of the table and chair frame, and divide the core stress zone, non-stress zone, and weld heat-affected zone.

[0013] S12. Based on the mechanical balance and thermal deformation trend of the overall frame structure, determine the reference positioning points so that the reference positioning points cover the geometric center and key stress nodes of the frame.

[0014] S13. Based on the reference positioning points and weld distribution, generate a clamping action point matrix so that the clamping points and weld points are symmetrically distributed and correspond one-to-one.

[0015] In a further embodiment of the present invention, step S2 includes:

[0016] S21. Multiple independently driven flexible clamping units are used, each corresponding to a reference positioning point and a clamping action point of the frame.

[0017] S22. Each clamping unit pre-clamps the component in a synchronous displacement and equidistant advance manner to maintain the preset geometric dimensions and parallelism of the component.

[0018] S23. After pre-clamping is completed, the contact pressure and component deformation at each clamping point are calibrated to ensure that there is no stress concentration in the initial clamping state.

[0019] In a further embodiment of the present invention, step S3 includes:

[0020] S31. Based on the material, wall thickness, and welding method of the frame components, calculate the heat input and thermal expansion of each weld point.

[0021] S32. Establish a dynamic mapping relationship between welding timing and clamping force, so that welding timing nodes and clamping force adjustment nodes are triggered synchronously and respond in conjunction.

[0022] S33. Determine the timing sequence of symmetrical welding and cross welding to ensure that the thermal deformation of the frame cancels each other out and avoids unidirectional twisting.

[0023] In a further embodiment of the present invention, step S4 includes:

[0024] S41. Divide all solder joints into symmetrical groups and synchronous groups. Solder joints in each group start and stop arcing simultaneously according to the preset timing sequence.

[0025] S42. The welding parameters of each welding gun are uniformly adjusted by the synchronous control module to keep the heat input rate and molten pool formation speed of each welding point consistent.

[0026] S43. During the welding process, the welding current and wire feeding speed of each weld point are matched in real time to avoid local overheating or insufficient welding.

[0027] In a further embodiment of the present invention, step S5 includes:

[0028] S51. Stress sensors and displacement sensors are installed at each clamping point to collect the stress value, strain value and displacement of the component in real time.

[0029] S52. Based on the collected data, calculate the deformation trend and stress distribution of the component in real time, and generate clamping force adjustment instructions;

[0030] S53. Drive each clamping unit to synchronously adjust the clamping force and displacement so that the component maintains the preset geometric accuracy and stress balance.

[0031] In a further embodiment of the present invention, step S6 includes:

[0032] S61. After welding is completed, release the clamping force of each clamping point gradually in a symmetrical direction and from the inside out.

[0033] S62. Release the clamping force in multiple gradients and small steps, and hold for a preset time after each gradient release to allow the stress on the component to be released gradually.

[0034] S63. After fully releasing the clamping force, allow the frame to cool naturally to complete the shaping process.

[0035] A multi-point synchronous welding anti-deformation clamping system for metal table and chair frames, realizing a method for multi-point synchronous welding anti-deformation clamping of metal table and chair frames, comprising:

[0036] The module includes a pre-positioning matrix construction module, a multi-point synchronous flexible clamping module, a welding timing-clamping force linkage control module, a multi-weld point synchronous welding module, a real-time deformation monitoring and dynamic adjustment module, and a symmetrical gradient unloading module.

[0037] The pre-positioning matrix construction module is used to generate the correspondence between the reference positioning points, clamping action points and welding points of the table and chair frame;

[0038] The multi-point synchronous flexible clamping module is used to perform multi-point synchronous flexible pre-clamping on the frame components;

[0039] The welding timing-clamping force linkage control module is used to establish a dynamic mapping relationship between welding timing and clamping force;

[0040] The multi-weld-point synchronous welding module is used to perform synchronous arc-starting welding of multiple weld points;

[0041] The real-time deformation monitoring and dynamic adjustment module is used to collect stress and strain data in real time and dynamically adjust the clamping force.

[0042] The symmetric gradient unloading module is used to release the clamping force in the order of symmetric relaxation and gradient unloading.

[0043] In a further embodiment of the present invention, the multi-point synchronous flexible clamping module includes:

[0044] Multiple independent drive clamping units, synchronous displacement drive mechanism, flexible contact components, and clamping force calibration unit;

[0045] The multiple sets of independent drive clamping units correspond to the reference positioning points and clamping action points of the frame;

[0046] The synchronous displacement driving mechanism drives each clamping unit to move synchronously and advance at equal intervals.

[0047] The flexible contact component is used to make flexible contact with the component to avoid rigid damage;

[0048] The clamping force calibration unit is used to calibrate the contact pressure and component deformation at each clamping point.

[0049] In a further embodiment of the present invention, the real-time deformation monitoring and dynamic adjustment module includes:

[0050] Stress sensor, displacement sensor, data acquisition unit, deformation trend calculation unit, clamping force adjustment command generation unit, synchronous adjustment drive unit;

[0051] The stress sensor and displacement sensor are set at each clamping point to collect stress, strain and displacement data in real time.

[0052] The data acquisition unit is used to collect and transmit monitoring data;

[0053] The deformation trend calculation unit is used to calculate the deformation trend and stress distribution of the component.

[0054] The clamping force adjustment command generation unit is used to generate clamping force adjustment commands;

[0055] The synchronous adjustment drive unit is used to drive each clamping unit to synchronously adjust the clamping force and displacement.

[0056] The beneficial effects of this invention are:

[0057] 1. Step S1 constructs a multi-point adaptive pre-positioning matrix based on the component cross-section, weld distribution and stress characteristics of the metal table and chair frame, clarifies the correspondence between the reference positioning point, clamping action point and weld point, provides a precise positioning basis for the linkage control of welding sequence and clamping force, avoids the aggravation of thermal deformation due to positioning deviation, and improves shape control accuracy from the source.

[0058] 2. Step S2, based on the pre-positioning matrix, implements multi-point synchronous flexible pre-clamping on the main load-bearing components to form a stable initial positioning constraint. This eliminates the gaps between components and avoids the prestress generated by rigid clamping, ensuring the stability of the initial state of linkage control and providing a reliable premise for subsequent dynamic adjustment of clamping force and offsetting thermal deformation.

[0059] 3. Step S3 establishes a welding timing-clamping force linkage model based on the component's thermal expansion coefficient and welding heat input characteristics. This solves the problem of the lack of a linkage mechanism between the two in the existing model. By clarifying the synchronous welding timing nodes and the dynamic force values ​​of each clamping point, the model achieves coordinated shape control of welding and clamping, thereby suppressing thermal deformation from the root.

[0060] 4. Step S4: Perform multi-point synchronous arc welding according to the linkage model, synchronously control the welding parameters of each weld point, ensure uniform heat input matching of each weld point, avoid uneven local heat input aggravating deformation, and achieve precise temperature control and synchronous operation in the welding process with the linkage model, taking into account both welding efficiency and shape control effect.

[0061] 5. Step S5 dynamically adjusts the clamping force and displacement by collecting stress and strain data at the clamping points in real time, thereby achieving real-time cancellation of thermal deformation during welding. This further improves the linkage control logic, solves the existing defects of not being able to respond to thermal deformation in real time, and maintains the preset geometric accuracy of the frame throughout the process.

[0062] 6. In step S6, the clamping force is released in the order of symmetrical relaxation and gradient unloading, so that the frame can cool and solidify naturally without forced constraints, avoiding secondary deformation during unloading, consolidating the effect of linkage control and real-time shape control, and ensuring that the final metal table and chair frame has accurate geometric dimensions and stable structure.

[0063] By coordinating the steps, a complete closed loop of "positioning-clamping-welding-shape control-unloading" is constructed, which solves the defect of the existing lack of a linkage mechanism between welding sequence and clamping force. It does not require complex equipment modification, is compatible with existing production lines, and balances welding efficiency and deformation prevention, thereby improving the production quality and pass rate of metal table and chair frames. Attached Figure Description

[0064] Figure 1 This is a flowchart of the steps of the method of the present invention;

[0065] Figure 2 This is a flowchart of step S1;

[0066] Figure 3 This is a flowchart of step S2;

[0067] Figure 4 This is a flowchart of step S3;

[0068] Figure 5 This is a flowchart of step S4;

[0069] Figure 6 This is a flowchart of step S5;

[0070] Figure 7 This is the flowchart for step S6. Detailed Implementation

[0071] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0072] In the description of this application, it should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. For ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0073] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and are not limited in number; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0074] It should be noted that in the description of this application, the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0075] It should be noted that, in this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0076] This embodiment provides a method for multi-point synchronous welding and anti-deformation clamping of metal table and chair frames, including the following steps:

[0077] S1. Based on the component cross-section, weld distribution and stress characteristics of the metal table and chair frame, construct a multi-point adaptive pre-positioning matrix to determine the correspondence between the reference positioning point, clamping action point and weld point of each component.

[0078] Specifically, metal table and chair frames are mainly composed of metal components such as crossbeams, longitudinal beams, and columns. Different components have different cross-sectional shapes (e.g., circular, square, rectangular) and dimensions, and the distribution, length, and thickness of welds vary. Furthermore, each component bears different loads during use, resulting in significantly different stress characteristics. To achieve precise clamping and weld deformation prevention, a comprehensive inspection of all components is necessary to obtain specific parameters of the component cross-sections (e.g., cross-sectional dimensions, wall thickness, and geometry). Specialized testing equipment is used to mark the specific locations, distribution densities, and spacing of all welds. Then, mechanical analysis is employed to clarify the stress conditions of each component during welding and use, identifying key stress-bearing areas and stress concentration zones. Based on all the data obtained above, a multi-point adaptive pre-positioning matrix is ​​constructed. This matrix can adaptively match the positioning requirements of each component according to the actual situation of the component, clearly delineate the reference positioning point (used to determine the reference position of the component and ensure positioning accuracy), clamping action point (used to apply clamping force and fix the component), and the specific position of the weld point for each component. At the same time, a one-to-one correspondence between the three is established to ensure that the subsequent clamping and welding actions can be accurately matched, laying the foundation for subsequent anti-deformation clamping and synchronous welding.

[0079] S2. Based on the pre-positioning matrix, multi-point synchronous flexible pre-clamping is implemented on the main load-bearing components of the table and chair frame to form initial positioning constraints in three-dimensional space.

[0080] The main load-bearing components are the core parts of the metal table and chair frame, mainly including crossbeams, longitudinal beams, and columns. Their positioning accuracy and clamping stability directly determine the welding quality and geometric accuracy of the entire frame. Improper clamping can easily lead to deformation. Therefore, it is necessary to strictly follow the pre-positioning matrix constructed in S1, select clamping units that match the number of clamping points, and implement multi-point synchronous flexible pre-clamping of the main load-bearing components. During the clamping process, it is necessary to ensure that all clamping units move synchronously to avoid uneven force on the components due to different clamping sequences. At the same time, a flexible clamping method is adopted, and flexible contact materials are used to contact the components to prevent damage to the component surface caused by rigid clamping and to avoid excessive clamping force that could cause prestress in the components. Through this multi-point synchronous flexible pre-clamping, each main load-bearing component is precisely fixed in three-dimensional space, forming a stable initial positioning constraint, ensuring that the relative positions between the components meet the design requirements, without offset or gaps, thus preparing for subsequent synchronous welding.

[0081] S3. Based on the component's thermal expansion coefficient and welding heat input characteristics, establish a welding timing-clamping force linkage model to determine the timing nodes of synchronous welding and the dynamic force values ​​of each clamping point.

[0082] During welding, the heat generated causes thermal expansion of the metal component, leading to thermal deformation. The clamping force directly affects the suppression of this deformation; excessive clamping force can cause plastic deformation after welding, while insufficient force fails to effectively suppress it. Therefore, it is necessary to first determine the coefficient of thermal expansion of the component material (different metals have different coefficients, such as steel and aluminum), and then analyze the heat input characteristics during welding, including the influence of parameters such as welding current, arc voltage, and welding speed on the heat input, clarifying the relationship between heat input and component thermal deformation. Based on this analysis, a welding sequence-clamping force linkage model is established. This model links the welding sequence with the clamping force, identifies key timing nodes for synchronous welding (such as arc initiation time, welding duration, and arc termination time), and calculates the dynamic clamping force value for each clamping point based on the heat input at different timing nodes. This allows the clamping force to be adjusted in real time according to changes in the welding sequence, adapting to the thermal deformation requirements of different welding stages and reducing thermal deformation at its source.

[0083] S4. Perform synchronous arc welding of multiple welding points according to the linkage model, and synchronously control the welding current, wire feeding speed and welding time of each welding point to make the heat input of each welding point uniformly matched.

[0084] After completing the pre-clamping and linkage model establishment, the multi-point synchronous welding process is initiated according to the welding timing nodes and dynamic clamping force values ​​determined by the model. During the welding process, it is necessary to ensure that all weld points ignite synchronously to avoid localized thermal expansion caused by some weld points igniting first and others later, which could lead to frame deformation. Simultaneously, the welding parameters of each welding torch are uniformly adjusted through the synchronous control module, focusing on controlling three key parameters: welding current, wire feed speed, and welding time, to ensure uniform heat input matching at each weld point. Specifically, the welding current and wire feed speed must be matched to avoid situations where excessive current and insufficient wire feed speed lead to localized overheating and burning through the component, or excessive current and excessive wire feed speed lead to weak welds. The welding time is reasonably set according to the weld length and thickness to ensure consistent weld strength at each weld point. Through the above synchronous control, localized deformation caused by uneven heat input is effectively avoided, ensuring welding quality.

[0085] S5. During the welding process, stress and strain data of each clamping point are collected in real time, and the clamping force and displacement of each clamping point are dynamically adjusted to counteract welding thermal deformation in real time.

[0086] Thermal deformation during welding is dynamic, and relying solely on preset clamping forces cannot completely suppress it. Therefore, real-time monitoring and dynamic adjustment are necessary. Stress and displacement sensors are installed at each clamping point. These sensors collect stress, strain, and displacement data of the component in real time and transmit the data to the control center. The control center analyzes the data to determine the deformation trend and stress distribution of the component. If thermal deformation exceeding the allowable range is detected, clamping force and displacement adjustment commands are immediately generated, driving each clamping unit to synchronously adjust the clamping force and displacement position. By adjusting the distribution and magnitude of the clamping force, the thermal deformation generated during welding is offset in real time, ensuring that the component maintains the preset geometric accuracy throughout the welding process and preventing deformation accumulation.

[0087] S6. After welding is completed, release the clamping force gradually in the order of symmetrical relaxation and gradient unloading, so that the frame can cool and solidify naturally without forced constraints.

[0088] After welding, residual welding stress will remain inside the component. If the clamping force is released rapidly all at once, it will cause a sudden release of welding stress, leading to secondary deformation of the frame. If an asymmetric unloading method is used, it will cause uneven stress on the frame, which will also cause deformation. Therefore, the clamping force should be released gradually in the order of symmetrical relaxation and gradient unloading: First, according to the symmetrical structure of the frame, the clamping points at symmetrical positions should be relaxed simultaneously to avoid uneven stress on one side; second, the clamping force should be released gradually in multiple gradients. After releasing a certain proportion of the clamping force in each gradient, a preset resting time should be maintained to allow the welding stress inside the component to be released gradually, avoiding sudden stress changes; after the clamping force is completely released, the frame should be placed in a room temperature environment to cool naturally. During the cooling process, collisions and vibrations should be avoided to ensure that the frame slowly sets without forced constraints, further consolidating the anti-deformation effect and ensuring the stability of the frame's geometric accuracy.

[0089] In this embodiment, step S1 includes:

[0090] S11. Measure the cross-sectional parameters and weld locations of the crossbeams, longitudinal beams, and columns of the table and chair frame, and divide the core stress zone, non-stress zone, and weld heat-affected zone.

[0091] As the core components of the frame, the cross-sectional parameters and weld locations of beams, longitudinal beams, and columns directly affect the positioning accuracy and welding deformation control. First, professional 3D scanning equipment and dimensional measuring tools are used to comprehensively map the beams, longitudinal beams, and columns, accurately obtaining the cross-sectional parameters of each component, including cross-sectional shape, outer diameter, inner diameter, and wall thickness, ensuring data accuracy. Simultaneously, weld inspection instruments are used to comprehensively inspect all welds, marking their start and end positions, length, width, and distribution, clarifying the connection relationship between the welds and the components. Based on the cross-sectional parameters and weld location data obtained from the survey, and combined with the stress analysis results of the components, each component is divided into three regions: the core stress zone (the area where the component bears the main load and stress concentration during use, such as the connection between the beam and the column), the non-stress zone (the area in the component where the stress is relatively small and has little impact on the stability of the frame), and the weld heat-affected zone (a certain range around the weld, where the temperature changes drastically during welding and is prone to thermal deformation, usually within 5-10 mm around the weld), providing a basis for the subsequent determination of the reference positioning point and clamping action point.

[0092] S12. Based on the mechanical balance and thermal deformation trend of the overall frame structure, determine the reference positioning points so that the reference positioning points cover the geometric center and key stress nodes of the frame.

[0093] The reference positioning point is the core of frame positioning, and its rationality directly determines the positioning accuracy and mechanical balance of the entire frame. Firstly, mechanical simulation analysis is used to simulate the stress conditions of the frame during use. Combined with the overall structural characteristics of the frame, the mechanical balance requirements are analyzed to ensure that the reference positioning point can provide stable positioning support for the frame, maintaining stress balance during pre-clamping and welding. Simultaneously, thermal deformation simulation is used to analyze the thermal deformation trend of the frame during welding, identifying areas of significant thermal deformation. Based on the above analysis, the geometric center of the frame is selected as the core reference positioning point because it ensures the overall symmetry of the frame and reduces positioning deviations. At the same time, key stress nodes of each component (such as the center point of the core stress area and the nodes at component connections) are selected as auxiliary reference positioning points to ensure that the reference positioning points cover the geometric center of the frame and all key stress nodes, forming a stable positioning system and providing accurate references for subsequent clamping and welding.

[0094] S13. Generate a matrix of clamping action points based on the reference positioning points and weld distribution, so that the clamping points and weld points are symmetrically distributed and have a one-to-one correspondence.

[0095] The clamping points must be matched with the reference positioning points and weld distribution to ensure that the clamping force can be accurately applied to key positions and effectively suppress welding thermal deformation. First, based on the reference positioning points determined in S12, clamping points are selected within a reasonable range around each reference positioning point to ensure that the clamping points can effectively support the reference positioning points while avoiding the heat-affected zone of the weld to prevent damage to the weld from the clamping force. Combining the weld distribution marked in S11, the specific location of each weld point is determined. Then, the clamping points are matched with the weld points to ensure that each weld point has a corresponding clamping point, and that the clamping points and weld points are symmetrically distributed, i.e., weld points at symmetrical positions on the frame correspond to clamping points at symmetrical positions. All the positions of the clamping points, the corresponding reference positioning points, and the corresponding weld point information are compiled and summarized to generate a clamping point matrix, clarifying the correspondence between the three to ensure that subsequent clamping actions can accurately match the weld points, providing a guarantee for synchronous welding and deformation prevention control.

[0096] In this embodiment, step S2 includes:

[0097] S21. Multiple independently driven flexible clamping units are used, each corresponding to a reference positioning point and a clamping action point of the frame.

[0098] To achieve multi-point synchronous flexible pre-clamping, multiple independently driven flexible clamping units are required. The number of clamping units is consistent with the total number of reference positioning points and clamping action points, ensuring that each reference positioning point and clamping action point has a corresponding clamping unit. Each clamping unit is equipped with an independent drive mechanism, enabling independent displacement adjustment and clamping force control. This allows for precise adjustment of the clamping unit's position and clamping force according to the clamping requirements at different locations. Simultaneously, the contact ends of the clamping units are made of flexible materials (such as rubber or silicone), possessing elasticity and cushioning properties. This allows for flexible contact with the component surface, avoiding scratches, dents, and other damage caused by rigid clamping. It also reduces pre-stress in the component due to excessive clamping force, ensuring the safety and rationality of the pre-clamping process.

[0099] S22. Each clamping unit pre-clamps the component in a synchronous displacement and equidistant advance manner to maintain the preset geometric dimensions and parallelism of the component.

[0100] During pre-clamping, it is essential to ensure that all clamping units move synchronously to avoid uneven force distribution and positional shifts in the components due to asynchronous movements. A synchronization control module controls all clamping units to move synchronously and advance at equal intervals at the same speed, ensuring that each clamping unit contacts the component surface simultaneously and preventing situations where some clamping units are already clamped while others are not yet in contact. During advancement, the positional changes of each component are monitored in real time. Based on preset geometric requirements, the advancement distance of the clamping units is adjusted to ensure that the relative positions of the components meet design standards. Simultaneously, the parallelism between crossbeams and longitudinal beams, and between columns and crossbeams, is checked to prevent tilting or shifting, maintaining the preset geometric accuracy of the components in three-dimensional space and forming stable initial positioning constraints.

[0101] S23. After pre-clamping is completed, the contact pressure and component deformation at each clamping point are calibrated to ensure that there is no stress concentration in the initial clamping state.

[0102] After pre-clamping, the clamping effect needs to be fully calibrated to avoid stress concentration in the component due to uneven or excessive clamping force, which could affect subsequent welding quality and deformation prevention. Pressure sensors installed on each clamping unit collect contact pressure data at each clamping point in real time and compare it with the preset clamping force range. If the contact pressure at some clamping points is too high or too low, the clamping force of the corresponding clamping unit is adjusted promptly to ensure uniform contact pressure at all clamping points. Simultaneously, displacement sensors detect minute deformations in the component to determine if plastic deformation has occurred due to excessive clamping force. If the deformation exceeds the allowable range, the clamping force is appropriately reduced until the component deformation returns to the normal range, ensuring no stress concentration in the initial clamping state and laying a solid foundation for thermal deformation control during subsequent welding.

[0103] In this embodiment, step S3 includes:

[0104] S31. Based on the material, wall thickness, and welding method of the frame components, calculate the heat input and thermal expansion of each weld point.

[0105] The material, wall thickness, and welding method of the components are key factors affecting heat input and thermal expansion. Different metal components have different coefficients of thermal expansion. The thicker the wall, the slower the heat conduction speed, and the greater the heat input requirement. Different welding methods (such as gas shielded welding and manual arc welding) also have different thermal efficiencies. First, the specific material of the frame components (e.g., Q235 steel, stainless steel, etc.) should be identified, and the corresponding coefficient of thermal expansion should be looked up. The wall thickness of each component should be measured, and the welding parameters (welding current, arc voltage, welding speed) should be reasonably set based on the thermal efficiency of the welding method. The heat input of each weld point can be calculated using the formula Q=I×U×η / v (where Q is the heat input, I is the welding current, U is the arc voltage, η is the welding thermal efficiency, and v is the welding speed). This ensures that the heat input meets the welding strength requirements while avoiding excessive thermal deformation due to excessive heat input. Based on the coefficient of thermal expansion and the temperature change corresponding to the heat input, the thermal expansion of each component should be calculated to clarify the correlation between thermal expansion and welding parameters, providing data support for the subsequent establishment of a linkage model.

[0106] S32. Establish a dynamic mapping relationship between welding timing and clamping force, so that welding timing nodes and clamping force adjustment nodes are triggered synchronously and respond in conjunction.

[0107] The welding process is divided into three key stages: arc initiation, welding, and arc termination. The heat input and thermal deformation vary at each stage, requiring different clamping forces. Therefore, it is necessary to establish a dynamic mapping relationship between welding timing and clamping force. First, the key nodes of the welding timing sequence are identified, including the arc initiation node (the time point when welding begins), the welding node (the stable phase of the welding process), and the arc termination node (the time point when welding ends). Each timing node corresponds to a different heat input state. Through multiple experiments, thermal deformation data corresponding to different timing nodes are obtained. Combined with thermal expansion analysis, the required clamping force for each timing node is determined, establishing a dynamic mapping relationship between timing nodes and clamping force. Simultaneously, a synchronous triggering mechanism is set up. When the welding process reaches a certain timing node, the clamping force adjustment command is triggered synchronously, enabling the clamping force to be adjusted to the dynamic force value corresponding to that node in a timely manner. This achieves a linked response between welding timing and clamping force, ensuring that the clamping force always adapts to the thermal deformation requirements.

[0108] S33. Determine the timing sequence of symmetrical welding and cross welding to ensure that the thermal deformation of the frame cancels each other out and avoids unidirectional twisting;

[0109] Metal table and chair frames are mostly symmetrical structures. If the welding sequence is not reasonable, such as welding only one side first or asymmetrical welding, the components on one side will expand due to heat before the components on the other side are heated, leading to unidirectional torsional deformation of the frame. Therefore, it is necessary to determine the symmetrical welding and cross-welding sequence based on the symmetrical structure of the frame. First, the weld points at symmetrical positions of the frame are divided into symmetrical groups, ensuring that the weld points in the symmetrical groups start, weld, and stop simultaneously, so that the components at symmetrical positions expand due to heat at the same time, and the thermal deformation cancels each other out. For asymmetrically distributed weld points, cross-welding is used, alternating the welding of weld points in different areas to avoid concentrated heating in local areas and reduce the accumulation of thermal deformation. By rationally planning the welding sequence, the thermal deformation of each area of ​​the frame cancels each other out, effectively preventing unidirectional torsion of the frame and improving the anti-deformation effect.

[0110] In this embodiment, step S4 includes:

[0111] S41. Divide all solder joints into symmetrical groups and synchronous groups. Solder joints in each group start and stop arcing simultaneously according to the preset timing sequence.

[0112] To achieve simultaneous welding of multiple weld points, all weld points are first divided into symmetrical groups and synchronous groups based on the structural characteristics and weld distribution of the frame. Symmetrical groups consist of weld points at symmetrical locations on the frame, such as the weld points at both ends of the left and right crossbeams, and the weld points at the connections between the front and rear columns and the crossbeams. Each symmetrical group contains two symmetrically distributed weld points, ensuring that the weld points in the symmetrical group initiate, weld, and terminate the welding synchronously, thus canceling out thermal deformation at symmetrical locations. Synchronous groups consist of multiple consecutive weld points on the same component, such as multiple weld points on a long crossbeam. Each synchronous group contains 3-5 weld points, ensuring that the weld points on the same component are welded synchronously, avoiding localized deformation of the component due to different welding sequences. Each group of weld points performs welding actions according to the preset timing sequence determined in S3, strictly controlling the arc initiation and termination times to ensure consistency in the timing of each group of weld points and reduce thermal deformation.

[0113] S42. The welding parameters of each welding gun are uniformly adjusted by the synchronous control module to keep the heat input rate and molten pool formation speed of each welding point consistent.

[0114] The stability of welding parameters directly affects the heat input rate and the molten pool formation speed. Inconsistent parameters across welding torches lead to uneven heat input at each weld point, resulting in differences in molten pool size and shape, which in turn causes localized deformation and welding quality issues. Therefore, a synchronous control module uniformly regulates the welding parameters of all welding torches, collecting parameters such as welding current, wire feed speed, and welding speed in real time and comparing them with preset parameters. If deviations occur, the welding torch parameters are adjusted promptly to ensure consistency across all torches. Simultaneously, the molten pool formation at each weld point is monitored in real time. Visual monitoring equipment is used to observe the size and shape of the molten pool, adjusting welding parameters to ensure a consistent molten pool formation speed across all weld points. This ensures uniform weld joint quality, a stable heat input rate, and prevents deformation caused by uneven heat input.

[0115] S43. During the welding process, the welding current and wire feeding speed of each weld point are matched in real time to avoid local overheating or insufficient welding.

[0116] Welding current and wire feed speed are two interrelated key parameters, and their matching directly affects weld quality and thermal deformation. During welding, excessive welding current and slow wire feed speed can lead to excessive localized heat input, causing overheating and burn-through of components, while also exacerbating thermal deformation. Conversely, insufficient welding current and excessive wire feed speed can result in incomplete penetration and insufficient weld strength, affecting the load-bearing capacity of the frame. Therefore, during welding, it is crucial to ensure real-time matching of welding current and wire feed speed at each weld point. Different current and wire feed speed matching schemes should be preset based on the weld thickness and length, and adjusted in real-time during welding to maintain the current and wire feed speed within a reasonable matching range. This prevents localized overheating or incomplete welding, balancing weld quality and deformation prevention.

[0117] In this embodiment, step S5 includes:

[0118] S51. Stress sensors and displacement sensors are installed at each clamping point to collect the stress value, strain value and displacement of the component in real time.

[0119] To monitor the deformation and stress distribution of components in real time during welding, stress and displacement sensors are installed at each clamping point. The sensors are positioned close to the component surface to ensure accurate and real-time data acquisition. Stress sensors collect real-time stress and strain values ​​at each clamping point, monitoring for stress concentration, excessive strain, and other issues. Displacement sensors collect real-time displacement data, monitoring the degree and direction of thermal deformation. The sensors transmit the collected real-time data to the control center via a data transmission module, providing precise data support for subsequent deformation analysis and adjustments, ensuring timely detection of abnormal deformation and preventing deformation accumulation.

[0120] S52. Based on the collected data, calculate the deformation trend and stress distribution of the component in real time, and generate clamping force adjustment instructions;

[0121] After receiving stress, strain, and displacement data collected by sensors, the control center filters and analyzes the data to remove interference and extract valid information. Through data processing, it calculates the deformation trend of the component in real time, determines the deformation direction (e.g., expansion, contraction) and deformation rate, and predicts subsequent deformation. Simultaneously, it analyzes the stress distribution of the component, identifying stress concentration areas and locations of excessive stress. Based on the deformation trend and stress distribution, and combined with the welding sequence-clamping force linkage model established by S3, it determines whether the current clamping force can effectively suppress thermal deformation. If the deformation exceeds the allowable range or stress concentration is found, a clamping force adjustment command is immediately generated, specifying the adjustment direction and amplitude for each clamping unit to ensure the adjustment command accurately adapts to the current deformation situation.

[0122] S53. Drive each clamping unit to synchronously adjust the clamping force and displacement so that the component maintains the preset geometric accuracy and stress balance;

[0123] The control center sends the generated clamping force adjustment command to the drive mechanism of each clamping unit, driving all clamping units to synchronously adjust the clamping force and displacement position. This prevents uneven stress on the component due to asynchronous adjustments, which could lead to new deformations. During the adjustment process, data collected by sensors is monitored in real time. Based on changes in component deformation and stress distribution, the clamping force and displacement are dynamically fine-tuned to ensure a smooth and precise adjustment process. Through synchronous adjustment, the component's deformation gradually returns to the allowable range, the stress distribution becomes more uniform, the preset geometric accuracy and stress balance are maintained, and thermal deformation generated during welding is offset in real time, ensuring the stability of the component during welding.

[0124] In this embodiment, step S6 includes:

[0125] S61. After welding is completed, release the clamping force gradually in a symmetrical direction and from the inside out.

[0126] After welding, residual welding stress remains inside the components. If the order of releasing the clamping force is not reasonable, it can lead to sudden stress release or uneven stress distribution, causing secondary deformation of the frame. Therefore, when releasing the clamping force, it is necessary to follow a symmetrical direction and proceed from the inside out: First, using the geometric center of the frame as a reference, the clamping points at symmetrical positions should simultaneously begin releasing the clamping force to ensure uniform stress distribution on both sides of the frame and avoid excessively rapid stress release on one side, which could cause the frame to tilt; Second, following the order from the inside out, first release the clamping force of the internal components of the frame (such as the inner beams and columns), and then release the clamping force of the outer components, gradually expanding the release range to ensure that the overall stress distribution of the frame is stable and to avoid deformation caused by local stress concentration.

[0127] S62. Release the clamping force in multiple gradients and small steps, and hold for a preset time after each gradient release to allow the stress on the component to be released gradually.

[0128] To avoid stress abrupt changes caused by rapid release of clamping force, a gradient, small-step release method is adopted. Based on the initial magnitude of the clamping force, it is divided into 5-8 gradients, with each gradient releasing 15%-20% of the clamping force to avoid excessive release at once. After each gradient of clamping force release is completed, a preset resting time (usually 10-15 seconds) is maintained to allow the welding stress inside the component to gradually release, giving the component sufficient time to adapt to stress changes and preventing deformation caused by sudden stress changes. During the resting period, the deformation of the component is monitored in real time. If abnormal deformation is detected, the release of clamping force is immediately paused, and the next gradient release operation is continued only after the deformation stabilizes.

[0129] S63. After completely releasing the clamping force, let the frame cool naturally to complete the shaping process.

[0130] After all the clamping forces of the gradients are fully released, the frame is placed in a room-temperature, vibration-free, and collision-free environment to allow it to cool naturally. Forced cooling (such as blowing air or watering) should be avoided as it can cause excessive temperature differences between the inside and outside of the component, leading to new thermal deformation. During the cooling process, the frame's temperature changes and deformation are monitored in real time to ensure that the frame does not shift or twist. Once the frame temperature has dropped to room temperature, the welding stress has been fully released, and the frame's geometric accuracy has stabilized, the shaping process is completed, ultimately resulting in a metal table and chair frame that meets the design requirements.

[0131] In addition, a multi-point synchronous welding anti-deformation clamping system for metal table and chair frames is provided, realizing a method for multi-point synchronous welding anti-deformation clamping of metal table and chair frames. The multi-point synchronous welding anti-deformation clamping system for metal table and chair frames includes:

[0132] The module includes a pre-positioning matrix construction module, a multi-point synchronous flexible clamping module, a welding timing-clamping force linkage control module, a multi-weld point synchronous welding module, a real-time deformation monitoring and dynamic adjustment module, and a symmetrical gradient unloading module.

[0133] The pre-positioning matrix construction module is used to generate the correspondence between the reference positioning points, clamping action points and welding points of the table and chair frame;

[0134] The pre-positioning matrix construction module is the foundation of the entire system, mainly composed of a data acquisition unit, a data analysis unit, and a matrix generation unit. The data acquisition unit collects cross-sectional parameters, weld distribution data, and stress characteristic data of each component of the metal table and chair frame, obtaining precise data through 3D scanning equipment, weld inspection instruments, and mechanical sensors. The data analysis unit processes and analyzes the collected data, dividing it into core stress zones, non-stress zones, and weld heat-affected zones, determining the positions of reference positioning points, clamping action points, and weld points. Based on the data analysis results, the matrix generation unit constructs a multi-point adaptive pre-positioning matrix, clarifying the one-to-one correspondence between reference positioning points, clamping action points, and weld points, and sends the generated matrix data to other modules, providing a reference basis for subsequent clamping and welding.

[0135] The multi-point synchronous flexible clamping module is used to perform multi-point synchronous flexible pre-clamping on the frame components;

[0136] The multi-point synchronous flexible clamping module is the core module for pre-clamping, mainly composed of clamping units, synchronous drive units, and calibration units. The clamping units employ multiple independently driven flexible clamping structures equipped with flexible contact components, enabling flexible contact with the component and avoiding rigid damage. The synchronous drive unit receives positioning data sent by the pre-positioning matrix construction module and controls all clamping units to synchronously displace and advance at equal intervals, achieving multi-point synchronous clamping. The calibration unit calibrates the clamping effect by collecting data through pressure and displacement sensors and adjusting the clamping force to ensure no stress concentration in the pre-clamping state and that the component maintains the preset geometric accuracy.

[0137] The welding timing-clamping force linkage control module is used to establish a dynamic mapping relationship between welding timing and clamping force;

[0138] The welding timing-clamping force linkage control module is responsible for linking welding timing and clamping force, and mainly consists of a parameter analysis unit, a model building unit, and a synchronization triggering unit. The parameter analysis unit analyzes the thermal expansion coefficient and welding heat input characteristics of the component, and calculates the heat input and thermal expansion. Based on the parameter analysis results, the model building unit establishes a welding timing-clamping force linkage model and determines the dynamic clamping force value corresponding to each timing node. The synchronization triggering unit sets the timing triggering mechanism to ensure that welding timing nodes and clamping force adjustment nodes are triggered synchronously, ensuring that the clamping force can be adjusted in real time according to the welding timing to adapt to thermal deformation requirements.

[0139] The multi-weld-point synchronous welding module is used to perform synchronous arc-starting welding of multiple weld points;

[0140] The multi-point synchronous welding module is responsible for achieving synchronous welding of multiple weld points. It mainly consists of a welding torch unit, a synchronization control unit, and a parameter control unit. The welding torch unit is equipped with multiple welding torches, each corresponding to a weld point, ensuring that each weld point has a corresponding welding torch. The synchronization control unit receives timing commands from the linkage control module and controls each welding torch to synchronously start, weld, and terminate the arc, ensuring consistent welding timing. The parameter control unit is used to uniformly control parameters such as welding current, wire feed speed, and welding time of each welding torch, ensuring uniform heat input matching for each weld point and avoiding local overheating or insufficient welding.

[0141] The real-time deformation monitoring and dynamic adjustment module is used to collect stress and strain data in real time and dynamically adjust the clamping force.

[0142] The real-time deformation monitoring and dynamic adjustment module is responsible for real-time monitoring and dynamic adjustment during the welding process. It mainly consists of a sensor unit, a data processing unit, and an adjustment drive unit. The sensor unit includes stress sensors and displacement sensors, which are installed at each clamping point to collect stress, strain, and displacement data of the component in real time. The data processing unit analyzes and processes the collected data, calculates the deformation trend and stress distribution of the component, and determines whether the clamping force needs to be adjusted. The adjustment drive unit receives the adjustment commands generated by the data processing unit and drives each clamping unit to synchronously adjust the clamping force and displacement to counteract welding thermal deformation in real time.

[0143] The symmetric gradient unloading module is used to release the clamping force in the order of symmetric relaxation and gradient unloading.

[0144] The symmetrical gradient unloading module is responsible for releasing the clamping force after welding is completed. It mainly consists of an unloading control unit, a timing control unit, and a monitoring unit. The unloading control unit is used to set the release sequence and gradient of the clamping force, releasing the clamping force in multiple gradients according to the symmetrical direction and from the inside out. The timing control unit is used to control the release time and resting time of each gradient to ensure that the stress is released gradually. The monitoring unit monitors the deformation of the component in real time. If abnormal deformation occurs, the unloading operation is paused in time and resumed after the deformation stabilizes, ensuring that the frame does not undergo secondary deformation during the unloading process.

[0145] In this embodiment, the multi-point synchronous flexible clamping module includes:

[0146] Multiple independent drive clamping units, synchronous displacement drive mechanism, flexible contact components, and clamping force calibration unit;

[0147] The multiple sets of independent drive clamping units correspond to the reference positioning points and clamping action points of the frame;

[0148] The independent drive clamping unit is the core execution component of the multi-point synchronous flexible clamping module. Each unit is equipped with an independent drive motor, displacement adjustment mechanism, and clamping head. The number of units matches the total number of reference positioning points and clamping action points of the frame, ensuring that each reference positioning point and clamping action point has a corresponding clamping unit. Each clamping unit can independently achieve displacement adjustment and clamping force control. It can precisely adjust the position of the clamping head and the magnitude of the clamping force according to the clamping requirements of different locations, adapting to the cross-sectional shape and size of different components to ensure clamping accuracy and stability. Simultaneously, each clamping unit is connected to a synchronous control system, capable of receiving commands from the synchronous displacement drive mechanism to achieve synchronized action.

[0149] The synchronous displacement driving mechanism drives each clamping unit to move synchronously and advance at equal intervals.

[0150] The synchronous displacement drive mechanism mainly consists of a drive controller, a transmission mechanism, and position sensors, and is responsible for controlling the synchronous movement of all independent drive clamping units. The drive controller receives positioning data and clamping commands from the pre-positioning matrix construction module, generates synchronous drive signals, and drives each clamping unit to move synchronously through the transmission mechanism (such as a lead screw or guide rail). The position sensors collect the displacement data of each clamping unit in real time and feed it back to the drive controller. The controller adjusts the drive signals according to the displacement data to ensure that each clamping unit advances at the same speed and distance, avoiding component offset and uneven force caused by asynchronous movements.

[0151] The flexible contact component is used to make flexible contact with the component to avoid rigid damage;

[0152] Flexible contact components are installed on the clamping heads of each clamping unit. They are made of flexible materials with good elasticity and wear resistance (such as rubber, silicone, polyurethane, etc.), and their shape can be adapted to the cross-sectional shape of the component (e.g., an arc-shaped contact head for circular components and a flat contact head for square components). Flexible contact components can increase the contact area with the component surface, reduce contact pressure, and avoid scratches, dents, and other damage to the component surface caused by rigid clamping. At the same time, they can also buffer the clamping force, reduce the pre-stress generated by clamping, and ensure the safety and rationality of the pre-clamping process.

[0153] The clamping force calibration unit is used to calibrate the contact pressure and component deformation at each clamping point.

[0154] The clamping force calibration unit mainly consists of a pressure sensor, a displacement sensor, and a calibration controller. The pressure sensor is installed between the clamping head and the flexible contact component to collect contact pressure data at each clamping point in real time. The displacement sensor is installed on the clamping unit to collect data on minute deformations of the component in real time. The calibration controller receives the data collected by the sensors and compares it with preset clamping force ranges and deformation thresholds. If the contact pressure at some clamping points is too high or too low, or if the deformation of the component exceeds the allowable range, the controller generates a calibration command to adjust the clamping force of the corresponding clamping unit until the contact pressure at all clamping points is uniform and the deformation of the component meets the standard, ensuring that there is no stress concentration in the initial clamping state.

[0155] In this embodiment, the real-time deformation monitoring and dynamic adjustment module includes:

[0156] Stress sensor, displacement sensor, data acquisition unit, deformation trend calculation unit, clamping force adjustment command generation unit, synchronous adjustment drive unit;

[0157] The stress sensor and displacement sensor are set at each clamping point to collect stress, strain and displacement data in real time.

[0158] The stress sensor employs a resistance strain gauge, which is attached to the surface of the component at each clamping point. It can detect the stress and strain values ​​of the component in real time, accurately reflecting the stress state and deformation degree. The displacement sensor uses a laser displacement sensor, mounted on the clamping unit and aligned with the component surface at the clamping point. It collects the displacement data of the component in real time, monitoring the direction and magnitude of thermal deformation. Both sensors have sampling frequencies that meet the requirements for real-time monitoring, enabling rapid data acquisition and ensuring data timeliness and accuracy, providing support for subsequent data analysis and adjustments.

[0159] The data acquisition unit is used to collect and transmit monitoring data;

[0160] The data acquisition unit mainly consists of a data acquisition card, a signal amplifier, and a data transmission module. It is responsible for receiving raw data from stress and displacement sensors. The signal amplifier amplifies the weak signals acquired by the sensors, removes noise interference, and improves data clarity. The data acquisition card converts analog signals into digital signals for subsequent processing. The data transmission module uses wired or wireless transmission methods to transmit the processed digital data to the deformation trend calculation unit in real time, ensuring fast and accurate data transmission and providing timely data support for real-time adjustments.

[0161] The deformation trend calculation unit is used to calculate the deformation trend and stress distribution of the component.

[0162] The deformation trend calculation unit receives monitoring data transmitted from the data acquisition unit and filters, analyzes, and calculates the data using specialized data processing algorithms. First, it removes interfering data and extracts valid data. Then, it calculates the deformation trend of the component, including deformation direction and rate, and predicts subsequent deformation. Simultaneously, it analyzes the stress distribution of the component, identifies stress concentration areas and locations of excessive stress, and determines whether the current deformation exceeds the allowable range. This provides a basis for adjusting the clamping force and ensures the accuracy of the adjustment commands.

[0163] The clamping force adjustment command generation unit is used to generate clamping force adjustment commands;

[0164] The clamping force adjustment command generation unit generates clamping force adjustment commands based on the analysis results of the deformation trend calculation unit and combined with the welding timing-clamping force linkage model. The commands clearly specify the adjustment direction (increasing or decreasing clamping force), adjustment range, and adjustment speed for each clamping unit, ensuring that the adjustment commands accurately adapt to the current deformation situation. Simultaneously, the command generation unit optimizes the adjustment commands to avoid secondary deformation of the component caused by excessive adjustment ranges, ensuring a smooth and precise adjustment process that effectively counteracts welding thermal deformation.

[0165] The synchronous adjustment drive unit is used to drive each clamping unit to synchronously adjust the clamping force and displacement.

[0166] The synchronous adjustment drive unit receives adjustment commands from the clamping force adjustment command generation unit. The drive controller then generates synchronous drive signals to drive each independent drive clamping unit to synchronously adjust the clamping force and displacement position. During the drive process, adjustment data from each clamping unit is collected in real time and fed back to the drive controller. The controller fine-tunes the drive signals based on the feedback data to ensure that all clamping units adjust synchronously, avoiding uneven stress on the component due to asynchronous adjustments and preventing new deformations. Through synchronous adjustment drive, the deformation of the component is gradually restored to the allowable range, maintaining the preset geometric accuracy and stress balance.

[0167] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A method for multi-point synchronous welding and anti-deformation clamping of metal table and chair frames, characterized in that, Includes the following steps: S1. Based on the component cross-section, weld distribution and stress characteristics of the metal table and chair frame, construct a multi-point adaptive pre-positioning matrix to determine the correspondence between the reference positioning point, clamping action point and weld point of each component. Step S1 includes: S11. Measure the cross-sectional parameters and weld locations of the crossbeams, longitudinal beams, and columns of the table and chair frame, and divide the core stress zone, non-stress zone, and weld heat-affected zone. S12. Based on the mechanical balance and thermal deformation trend of the overall frame structure, determine the reference positioning points so that the reference positioning points cover the geometric center and key stress nodes of the frame. S13. Generate a matrix of clamping action points based on the reference positioning points and weld distribution, so that the clamping points and weld points are symmetrically distributed and have a one-to-one correspondence. S2. Based on the pre-positioning matrix, multi-point synchronous flexible pre-clamping is implemented on the main load-bearing components of the table and chair frame to form initial positioning constraints in three-dimensional space. Step S2 includes: S21. Multiple independently driven flexible clamping units are used, each corresponding to a reference positioning point and a clamping action point of the frame. S22. Each clamping unit pre-clamps the component in a synchronous displacement and equidistant advance manner to maintain the preset geometric dimensions and parallelism of the component. S23. After pre-clamping is completed, the contact pressure and component deformation at each clamping point are calibrated to ensure that there is no stress concentration in the initial clamping state. S3. Based on the component's thermal expansion coefficient and welding heat input characteristics, establish a welding timing-clamping force linkage model to determine the timing nodes of synchronous welding and the dynamic force values ​​of each clamping point. S4. Perform synchronous arc welding of multiple welding points according to the linkage model, and synchronously control the welding current, wire feeding speed and welding time of each welding point to make the heat input of each welding point uniformly matched. S5. During the welding process, stress and strain data of each clamping point are collected in real time, and the clamping force and displacement of each clamping point are dynamically adjusted to counteract welding thermal deformation in real time. S6. After welding is completed, release the clamping force gradually in the order of symmetrical relaxation and gradient unloading, so that the frame can cool and solidify naturally without forced constraints.

2. The multi-point synchronous welding anti-deformation clamping method for metal table and chair frames according to claim 1, characterized in that, Step S3 includes: S31. Based on the material, wall thickness, and welding method of the frame components, calculate the heat input and thermal expansion of each weld point. S32. Establish a dynamic mapping relationship between welding timing and clamping force, so that welding timing nodes and clamping force adjustment nodes are triggered synchronously and respond in conjunction. S33. Determine the timing sequence of symmetrical welding and cross welding to ensure that the thermal deformation of the frame cancels each other out and avoids unidirectional twisting.

3. The multi-point synchronous welding anti-deformation clamping method for metal table and chair frames according to claim 1, characterized in that, Step S4 includes: S41. Divide all solder joints into symmetrical groups and synchronous groups. Solder joints in each group start and stop arcing simultaneously according to the preset timing sequence. S42. The welding parameters of each welding gun are uniformly adjusted by the synchronous control module to keep the heat input rate and molten pool formation speed of each welding point consistent. S43. During the welding process, the welding current and wire feeding speed of each weld point are matched in real time to avoid local overheating or insufficient welding.

4. The multi-point synchronous welding anti-deformation clamping method for metal table and chair frames according to claim 1, characterized in that, Step S5 includes: S51. Stress sensors and displacement sensors are installed at each clamping point to collect the stress value, strain value and displacement of the component in real time. S52. Based on the collected data, calculate the deformation trend and stress distribution of the component in real time, and generate clamping force adjustment instructions; S53. Drive each clamping unit to synchronously adjust the clamping force and displacement so that the component maintains the preset geometric accuracy and stress balance.

5. The multi-point synchronous welding anti-deformation clamping method for metal table and chair frames according to claim 1, characterized in that, Step S6 includes: S61. After welding is completed, release the clamping force of each clamping point gradually in a symmetrical direction and from the inside out. S62. Release the clamping force in multiple gradients and small steps, and hold for a preset time after each gradient release to allow the stress on the component to be released gradually. S63. After fully releasing the clamping force, allow the frame to cool naturally to complete the shaping process.

6. A multi-point synchronous welding anti-deformation clamping system for metal table and chair frames, implementing the multi-point synchronous welding anti-deformation clamping method for metal table and chair frames as described in claim 1, characterized in that, The multi-point synchronous welding anti-deformation clamping system for metal table and chair frames includes: The module includes a pre-positioning matrix construction module, a multi-point synchronous flexible clamping module, a welding timing-clamping force linkage control module, a multi-weld point synchronous welding module, a real-time deformation monitoring and dynamic adjustment module, and a symmetrical gradient unloading module. The pre-positioning matrix construction module is used to generate the correspondence between the reference positioning points, clamping action points and welding points of the table and chair frame; The multi-point synchronous flexible clamping module is used to perform multi-point synchronous flexible pre-clamping on the frame components; The welding timing-clamping force linkage control module is used to establish a dynamic mapping relationship between welding timing and clamping force; The multi-weld-point synchronous welding module is used to perform synchronous arc-starting welding of multiple weld points; The real-time deformation monitoring and dynamic adjustment module is used to collect stress and strain data in real time and dynamically adjust the clamping force. The symmetric gradient unloading module is used to release the clamping force in the order of symmetric relaxation and gradient unloading.

7. The multi-point synchronous welding anti-deformation clamping system for metal table and chair frames according to claim 6, characterized in that, The multi-point synchronous flexible clamping module includes: Multiple independent drive clamping units, synchronous displacement drive mechanism, flexible contact components, and clamping force calibration unit; The multiple sets of independent drive clamping units correspond to the reference positioning points and clamping action points of the frame; The synchronous displacement driving mechanism drives each clamping unit to move synchronously and advance at equal intervals. The flexible contact component is used to make flexible contact with the component to avoid rigid damage; The clamping force calibration unit is used to calibrate the contact pressure and component deformation at each clamping point.

8. The multi-point synchronous welding anti-deformation clamping system for metal table and chair frames according to claim 7, characterized in that, The real-time deformation monitoring and dynamic adjustment module includes: Stress sensor, displacement sensor, data acquisition unit, deformation trend calculation unit, clamping force adjustment command generation unit, synchronous adjustment drive unit; The stress sensor and displacement sensor are set at each clamping point to collect stress, strain and displacement data in real time. The data acquisition unit is used to collect and transmit monitoring data; The deformation trend calculation unit is used to calculate the deformation trend and stress distribution of the component. The clamping force adjustment command generation unit is used to generate clamping force adjustment commands; The synchronous adjustment drive unit is used to drive each clamping unit to synchronously adjust the clamping force and displacement.

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