An on-line detection method and system for the solder joint quality of a circuit component

Abstract

The present invention relates to the field of detection technology, and particularly to an on-line detection method and system for the solder joint quality of circuit components. By acquiring the real-time temperature data of each solder joint during the welding process, the present invention can monitor the temperature change of the solder joint in real time during the welding process and then adjust the preset welding parameters. The dynamic temperature change curve can help accurately extract the temperature gradient distribution data of each solder joint at different time nodes. Through real-time data feedback and analysis, the welding process can be automatically optimized according to the temperature change of each solder joint. This adjustment can perform optimal parameter configuration for different solder joints and different working conditions. By analyzing multi-dimensional data such as the thermal stress, external dynamic stress, and deformation comprehensive index of each solder joint, the quality of the solder joint can be evaluated more accurately. Furthermore, by combining real-time data acquisition and deformation analysis, automatic adjustment of welding parameters is realized, improving the stability and consistency of the solder joint quality and reducing the risk of unqualified solder joints.

Description

Technical Field

[0001] The present invention relates to the field of detection technologies, and particularly to an on-line detection method and system for the solder joint quality of circuit components. Background Art

[0002] During the welding process of copper bars and busbars, the process control of solder joints is very important. Improper welding may affect the electrical conductivity of the copper bars and busbars themselves, and further affect the stability of the entire power system. Therefore, the detection of the solder joint quality of circuit components is a crucial step in the electronic manufacturing process. For example, too high or too low welding temperature will cause physical property changes of the copper bars and busbars, which may lead to a decrease in electrical conductivity and even thermal damage to the copper bars and busbars. Therefore, for copper bars and busbars, ensuring the solder joint quality is crucial for ensuring their load-bearing capacity and stable operation. Quality detection helps prevent electrical connection problems caused by poor welding, thereby improving the reliability of the connection between the circuit board and the copper bars and busbars.

[0003] Currently, the methods for detecting the solder joint quality of circuit components mainly detect the solder joint quality of circuit components through automatic optical inspection. Among them, automatic optical inspection scans the solder joints through a camera and a high-resolution image acquisition system, and analyzes whether the quality of the detected solder joints is qualified through software. However, since the factors affecting the solder joint quality include the change in temperature during the welding process, which affects the fluidity of the solder and thus causes defects in the shape and surface characteristics of the solder joints, and the quality anomalies caused by factors such as the shaking during the cooling process of the solder joints, and automatic optical inspection can only perform static analysis on the quality of the solder joints after welding, it is impossible to adjust the welding process of the solder joints of circuit components according to the accurate reasons affecting the solder joint quality. Summary of the Invention

[0004] The main object of the present invention is to provide an on-line detection method for the solder joint quality of circuit components, aiming to solve the technical problems in the prior art.

[0005] The present invention proposes an on-line detection method for the solder joint quality of circuit components, including:

[0006] Obtaining the continuous real-time temperatures at multiple consecutive moments at each welding point of the circuit component during the welding process under preset welding parameters, and constructing a dynamic temperature change curve graph based on the multiple continuous real-time temperatures;

[0007] Extracting the temperature gradient distribution data of each welding point at multiple time nodes according to the dynamic temperature change curve graph, and determining the thermal stress region according to each temperature gradient distribution data;

[0008] Obtaining the displacement deformation amount and stress deformation amount at each welding point in each thermal stress region through a high-speed sensor, and obtaining the corresponding external dynamic deformation amount according to each displacement deformation amount and stress deformation amount;

[0009] Obtain the corresponding external dynamic stress according to each of the external dynamic deformation amounts, and obtain the total stress according to each of the external dynamic stresses and the thermal stress;

[0010] Obtain the deformation comprehensive index according to each of the total stresses, and judge the relationship between the deformation comprehensive index and the preset threshold interval;

[0011] If the deformation comprehensive index is greater than the upper limit value of the preset threshold interval, it is determined that the quality of the welding point is unqualified, and the preset welding parameters are reduced in real time according to the deformation comprehensive index;

[0012] If the deformation comprehensive index is less than the lower limit value of the preset threshold interval, it is determined that the quality of the welding point is unqualified, and the preset welding parameters are increased in real time according to the deformation comprehensive index;

[0013] If the deformation comprehensive index is within the preset threshold interval, obtain the solder joint radius after cooling of the corresponding solder joint, and obtain the corresponding moment of inertia according to each of the solder joint radii;

[0014] Obtain the corresponding solder joint deformation according to each of the moments of inertia and the solder joint radii, and judge whether the solder joint deformation is less than the preset deformation;

[0015] If the solder joint deformation is not less than the preset deformation, it is determined that the quality of the welding point is unqualified;

[0016] If the solder joint deformation is less than the preset deformation, it is determined that the quality of the welding point is qualified.

[0017] Preferably, the step of constructing a dynamic temperature change curve graph according to the multiple continuous real-time temperatures includes:

[0018] Obtain the parameter characteristics of each welding point, where the parameter characteristics include density, specific heat capacity, and thermal conductivity;

[0019] Obtain the initial temperature and heat source power of each welding point, and obtain the heat source temperature change rate according to the heat source power, density, and specific heat capacity;

[0020] Obtain the heat source diffusion rate according to the thermal conductivity, density, and specific heat capacity;

[0021] Obtain the second-order partial derivative of the X-axis temperature, the second-order partial derivative of the Y-axis temperature, and the second-order partial derivative of the Z-axis temperature in the X-axis direction, Y-axis direction, and Z-axis direction of the corresponding welding point according to the initial temperature;

[0022] Obtain the temperature spatial change rate according to the second-order partial derivative of the X-axis temperature, the second-order partial derivative of the Y-axis temperature, and the second-order partial derivative of the Z-axis temperature;

[0023] Obtain a time step based on multiple said continuous real-time temperatures, and obtain the real-time temperature of the welding point in the corresponding next continuous real-time temperature according to the time step, the temperature spatial change rate, the heat source diffusion rate, the heat source temperature change rate, and the initial temperature;

[0024] Taking time as the X-axis and temperature as the Y-axis, establish a time-temperature coordinate axis, and plot the initial temperature as the starting point on the time-temperature coordinate axis;

[0025] Taking the real-time temperature of the welding point corresponding to each time step as a connection point, plot it on the time-temperature coordinate axis, and connect the starting point and multiple connection points in sequence with a curve to obtain a dynamic temperature change curve graph.

[0026] Preferably, the step of obtaining the corresponding thermal stress according to each said temperature gradient distribution data and determining the thermal stress area according to the thermal stress includes:

[0027] Obtain the temperature change rate in the vertical direction and the temperature change rate in the horizontal direction according to each said temperature gradient distribution data;

[0028] Obtain the thermal expansion coefficient and elastic modulus of each welding point, and obtain the corresponding vertical strain force according to each said thermal expansion coefficient and the temperature change rate in the vertical direction;

[0029] Obtain the corresponding horizontal strain force according to each said thermal expansion coefficient and the temperature change rate in the horizontal direction, and obtain the corresponding Poisson's ratio according to each said horizontal strain force and vertical strain force;

[0030] Obtain the thermal stress at the corresponding welding point according to each said Poisson's ratio, thermal expansion coefficient, elastic modulus, and temperature gradient distribution data;

[0031] Judge whether the thermal stress is greater than a preset stress;

[0032] If the thermal stress is greater than the preset stress, determine the welding point corresponding to the thermal stress as the thermal stress area;

[0033] If the thermal stress is not greater than the preset stress, determine the welding point corresponding to the thermal stress as the non-thermal stress area.

[0034] Preferably, the step of obtaining the displacement deformation amount and stress deformation amount at each welding point in each thermal stress area through a high-speed sensor and obtaining the corresponding external dynamic deformation amount according to each said displacement deformation amount and stress deformation amount includes:

[0035] Obtain the initial abscissa, initial ordinate, and initial vertical coordinate of each welding point in each thermal stress area through a high-speed sensor;

[0036] Obtain the real-time abscissa, real-time ordinate, and real-time vertical coordinate of each welding point in each thermal stress area at each preset time point through a high-speed sensor;

[0037] Obtain the displacement deformation amount of the corresponding welding point according to each of the real-time abscissa, real-time ordinate, real-time vertical coordinate, initial abscissa, initial ordinate, and initial vertical coordinate;

[0038] Obtain the coefficient of thermal expansion, temperature gradient distribution data, and initial length of each welding point in each thermal stress area;

[0039] Obtain the stress deformation amount of the corresponding welding point according to each of the coefficient of thermal expansion, temperature gradient distribution data, and initial length;

[0040] Obtain the corresponding external dynamic deformation amount according to each of the stress deformation amount and displacement deformation amount.

[0041] Preferably, the step of obtaining the corresponding external dynamic stress according to each of the external dynamic deformation amounts and obtaining the corresponding total stress according to each of the external dynamic stresses and thermal stresses includes:

[0042] Perform a first-order time derivative process on each of the external dynamic deformation amounts to obtain the deformation rate of change;

[0043] Perform a second-order time derivative process on each of the deformation rates of change to obtain the deformation acceleration;

[0044] Obtain the elastic modulus and density of the corresponding welding point according to each of the external dynamic deformation amounts, and obtain the corresponding deformation stress according to each of the densities and deformation accelerations;

[0045] Obtain the corresponding inertial force according to each of the external dynamic deformation amounts and elastic modulus, and obtain the corresponding external dynamic stress according to each of the inertial forces and deformation stresses;

[0046] Obtain the thermal stress of each welding point, and obtain the corresponding total stress according to each of the thermal stresses and external dynamic stresses.

[0047] Preferably, the step of obtaining the corresponding deformation comprehensive index according to each of the total stresses includes:

[0048] Obtain the modulus characteristics of each welding point, where the modulus characteristics include elastic modulus and viscosity coefficient;

[0049] Obtain the corresponding elastic strain force according to each of the elastic modulus and total stress;

[0050] Obtain the yield strength of each welding point, and determine whether the total stress is greater than the yield strength;

[0051] If the total stress is greater than the yield strength, obtain the plastic modulus corresponding to the welding point, and obtain the corresponding plastic strain increment rate according to each of the plastic moduli, elastic strain forces, and total stresses;

[0052] Obtain the corresponding plastic strain force according to each of the plastic strain increment rates, total stresses, elastic strain forces, and elastic moduli;

[0053] Obtain the corresponding viscous strain force according to each of the viscosity coefficients and total stresses, and obtain the deformation comprehensive index according to each of the viscous strain forces, elastic strain forces, and plastic strain forces.

[0054] This application also provides an on-line detection system for the solder joint quality of a circuit component, including:

[0055] A construction module, configured to obtain the continuous real-time temperatures at multiple consecutive moments of each solder joint during the welding process of the circuit component under preset welding parameters, and construct a dynamic temperature change curve graph according to the multiple continuous real-time temperatures;

[0056] A determination module, configured to extract the temperature gradient distribution data of each solder joint at multiple time nodes according to the dynamic temperature change curve graph, and determine the thermal stress area according to each of the temperature gradient distribution data;

[0057] A first acquisition module, configured to obtain the displacement deformation amount and stress deformation amount at each solder joint in each thermal stress area through a high-speed sensor, and obtain the corresponding external dynamic deformation amount according to each of the displacement deformation amount and stress deformation amount;

[0058] A second acquisition module, configured to obtain the corresponding external dynamic stress according to each of the external dynamic deformation amounts, and obtain the total stress according to each of the external dynamic stresses and thermal stresses;

[0059] A first judgment module, configured to obtain the deformation comprehensive index according to each of the total stresses, and judge the relationship between the deformation comprehensive index and a preset threshold interval;

[0060] If the deformation comprehensive index is greater than the upper limit value of the preset threshold interval, determine that the quality of the solder joint is unqualified, and reduce the preset welding parameters in real time according to the deformation comprehensive index;

[0061] If the deformation comprehensive index is less than the lower limit value of the preset threshold interval, determine that the quality of the solder joint is unqualified, and increase the preset welding parameters in real time according to the deformation comprehensive index;

[0062] If the deformation comprehensive index is within the preset threshold interval, obtain the solder joint radius after cooling of the corresponding solder joint, and obtain the corresponding moment of inertia according to each of the solder joint radii;

[0063] A second judgment module, configured to obtain the corresponding solder joint deformation according to each of the moments of inertia and the solder joint radius, and judge whether the solder joint deformation is less than a preset deformation;

[0064] If the solder joint deformation is not less than the preset deformation, it is determined that the quality of the solder joint is unqualified;

[0065] If the solder joint deformation is less than the preset deformation, it is determined that the quality of the solder joint is qualified.

[0066] Preferably, the determination module includes:

[0067] A first acquisition unit, configured to obtain the vertical direction temperature change rate and the horizontal direction temperature change rate according to each of the temperature gradient distribution data;

[0068] A second acquisition unit, configured to obtain the thermal expansion coefficient and elastic modulus of each solder joint, and obtain the corresponding vertical strain force according to each of the thermal expansion coefficients and the vertical direction temperature change rate;

[0069] A third acquisition unit, configured to obtain the corresponding horizontal strain force according to each of the thermal expansion coefficients and the horizontal direction temperature change rate, and obtain the corresponding Poisson's ratio according to each of the horizontal strain forces and the vertical strain forces;

[0070] A fourth acquisition unit, configured to obtain the thermal stress at the corresponding solder joint according to each of the Poisson's ratios, thermal expansion coefficients, elastic moduli and temperature gradient distribution data;

[0071] A determination unit, configured to judge whether the thermal stress is greater than a preset stress;

[0072] If the thermal stress is greater than the preset stress, the solder joint corresponding to the thermal stress is determined as the thermal stress area;

[0073] If the thermal stress is not greater than the preset stress, the solder joint corresponding to the thermal stress is determined as the non-thermal stress area.

[0074] The present invention also provides a computer device, including a memory and a processor, where the memory stores a computer program, and when the processor executes the computer program, the steps of the above-mentioned on-line detection method for the quality of solder joints of circuit components are implemented.

[0075] The present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the above-mentioned on-line detection method for the quality of solder joints of circuit components are implemented.

[0076] The beneficial effects of the present invention are as follows: By obtaining the real-time temperature data of each welding point during the welding process, the present invention can monitor the temperature change of the solder joints in real time during the welding process, and then adjust the preset welding parameters, thereby avoiding solder joint defects caused by inappropriate temperatures. The dynamic temperature change curve can help accurately extract the temperature gradient distribution data of each welding point at different time nodes. By analyzing the temperature gradient, the possible thermally stressed areas during the welding process can be identified. By monitoring the temperature change in real time, it can ensure that the fluidity of the solder is within the most suitable range, thereby avoiding defects such as irregular solder joint shapes and incomplete welding. Through real-time data feedback and analysis, the system can automatically optimize the welding process according to the temperature change of each solder joint. This adaptive adjustment can perform optimal parameter configuration for different solder joints and different working conditions, thereby improving the overall welding quality. By obtaining the displacement deformation amount and stress deformation amount of each welding point in the thermally stressed area through high-precision sensors, the real-time monitoring of the welding process can be realized, and the welding parameters can be dynamically adjusted according to the real-time data, thereby avoiding a situation where problems cannot be corrected when discovered later. By analyzing multi-dimensional data such as the thermal stress, external dynamic stress, and deformation comprehensive index of each welding point, the quality of the welding point can be evaluated more accurately. Through the comprehensive analysis of the deformation, thermal stress, and post-cooling deformation during the welding process, these influencing factors can be comprehensively considered, and then the automatic adjustment of welding parameters can be realized by combining real-time data acquisition and deformation analysis, avoiding welding defects caused by external factors such as temperature and pressure, improving the stability and consistency of the solder joint quality, and reducing the risk of unqualified solder joints. Description of the Drawings

[0077] Figure 1 It is a schematic flowchart of the method according to an embodiment of the present invention.

[0078] Figure 2 It is a schematic structural diagram of the device according to an embodiment of the present invention.

[0079] Figure 3 It is a schematic internal structure diagram of a computer device according to an embodiment of the present application.

[0080] The realization, functional features, and advantages of the object of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed Embodiments

[0081] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0082] As Figures 1-3 shown, the present application provides an on-line detection method for the quality of solder joints of circuit components, including:

[0083] S1. Obtain the continuous real-time temperatures at multiple consecutive moments at each welding point during the welding process of the circuit component under preset welding parameters, and construct a dynamic temperature change curve graph based on the multiple continuous real-time temperatures. Among them, the preset welding parameters include welding duration and welding current;

[0084] S2. Extract the temperature gradient distribution data at each welding point at multiple time nodes according to the dynamic temperature change curve graph, and determine the thermal stress area according to each temperature gradient distribution data;

[0085] S3. Obtain the displacement deformation amount and stress deformation amount at each welding point in each thermal stress area through a high-speed sensor, and obtain the corresponding external dynamic deformation amount according to each displacement deformation amount and stress deformation amount;

[0086] S4. Obtain the corresponding external dynamic stress according to each external dynamic deformation amount, and obtain the total stress according to each external dynamic stress and thermal stress;

[0087] S5. Obtain the deformation comprehensive index according to each total stress, and judge the relationship between the deformation comprehensive index and the preset threshold interval;

[0088] If the deformation comprehensive index is less than the lower limit value of the preset threshold interval, it is determined that the quality of this welding point is unqualified;

[0089] If the deformation comprehensive index is within the preset threshold interval, obtain the solder joint radius after cooling of the corresponding welding point, and obtain the corresponding moment of inertia according to each solder joint radius;

[0090] S6. Obtain the corresponding solder joint deformation according to each moment of inertia and solder joint radius, and judge whether the solder joint deformation is less than the preset deformation;

[0091] If the solder joint deformation is not less than the preset deformation, it is determined that the quality of this welding point is unqualified;

[0092] If the solder joint deformation is less than the preset deformation, it is determined that the quality of this welding point is qualified.

[0093] As described in the above steps S1 - S6, the current method for detecting the quality of solder joints of circuit components mainly detects the quality of solder joints of circuit components through automatic optical inspection. Among them, automatic optical inspection scans the solder joints through a camera and a high - resolution image acquisition system, and analyzes whether the quality of the solder joints is qualified through software. However, the factors affecting the quality of solder joints include the influence of temperature changes during the welding process on the fluidity of the solder, which in turn leads to defects in the shape and surface characteristics of the solder joints (this is because during the welding process, the temperature in the welding area rises sharply, and the solder begins to change from solid to liquid. If the fluidity of the solder increases, and at this time if the temperature control is unstable, it may cause the solder to flow excessively or splash out, resulting in an uneven solder joint surface or excessive solder overflow causing a short circuit. Poor solder fluidity may lead to insufficient wettability in the welding area, forming voids or incomplete contact, resulting in insecure solder joints) and factors such as the shaking during the cooling process of the solder joints (for example, if shaking occurs during the cooling process, the solder may solidify prematurely in some areas while other parts remain unfrozen, resulting in unstable contact or weak solder joints), which lead to quality abnormalities. And automatic optical inspection can only perform static analysis on the quality of solder joints after welding is completed. Therefore, it is impossible to adjust the welding process of the solder joints of circuit components according to the accurate reasons affecting the quality of solder joints. The present invention obtains the real - time temperature at multiple consecutive moments at each welding point of the circuit component during the welding process under preset welding parameters, and constructs a dynamic temperature change curve graph based on the multiple consecutive real - time temperatures. The temperature gradient distribution data of each welding point at multiple time nodes is extracted through the dynamic temperature change curve graph, and the thermal stress area is determined according to each temperature gradient distribution data. Among them, the extraction of the temperature gradient distribution data of each welding point at multiple time nodes through the dynamic temperature change curve graph is calculated by the difference method or the numerical differentiation method. The acquisition method of the real - time temperature at multiple consecutive moments at the welding point can be obtained through infrared thermal imaging technology or temperature sensors, etc. By obtaining the real - time temperature data of each welding point during the welding process, the temperature change of the solder joints can be monitored in real - time during the welding process. If an abnormal temperature change (such as too high or too low temperature) of a certain solder joint is detected during the welding process, the preset welding parameters (welding time and welding current) can be adjusted immediately, thus avoiding solder joint defects caused by inappropriate temperature. Such adjustment is a real - time feedback during the welding process, ensuring that subsequent solder joints can reach the best quality. The dynamic temperature change curve can help accurately extract the temperature gradient distribution data of each welding point at different time nodes. The temperature gradient is one of the key factors affecting the quality of solder joints because it determines the fluidity and cooling rate of the solder, thus affecting the shape, strength, and stability of the solder joints. By analyzing the temperature gradient, the possible thermal stress areas during the welding process can be identified. These areas are usually the root causes of solder joint quality problems. By discovering these problem areas in advance, dynamic adjustment can be made during the welding process to reduce the negative impact of thermal stress on the solder joints.Since temperature changes can directly affect the fluidity of the solder, which in turn affects the shape and surface characteristics of the solder joints, by monitoring the temperature changes in real time, the fluidity of the solder can be ensured to be within the most suitable range, thus avoiding defects such as irregular solder joint shapes and incomplete soldering. Through real-time data feedback and analysis, the system can automatically optimize the soldering process according to the temperature changes of each solder joint. This adaptive adjustment can configure the optimal parameters for different solder joints and different working conditions, thereby improving the overall soldering quality. By using high-speed sensors to obtain the displacement deformation and stress deformation at each solder joint in each thermal stress area, and obtaining the corresponding external dynamic deformation according to each displacement deformation and stress deformation, obtaining the corresponding external dynamic stress according to each external dynamic deformation, obtaining the total stress according to each external dynamic stress and thermal stress, obtaining the deformation comprehensive index according to each total stress, and judging the relationship between the deformation comprehensive index and the preset threshold interval. If the deformation comprehensive index is greater than the upper limit value of the preset threshold interval, it is determined that the quality of the solder joint is unqualified, and the preset soldering parameters are reduced in real time according to the deformation comprehensive index. If the deformation comprehensive index is less than the lower limit value of the preset threshold interval, it is determined that the quality of the solder joint is unqualified, and the preset soldering parameters are increased in real time according to the deformation comprehensive index. If the deformation comprehensive index is within the preset threshold interval, the solder joint radius after cooling of the corresponding solder joint is obtained, and the corresponding moment of inertia is obtained according to each solder joint radius. The corresponding solder joint deformation is obtained according to each moment of inertia and solder joint radius, and it is judged whether the solder joint deformation is less than the preset deformation. If the solder joint deformation is not less than the preset deformation, it is determined that the quality of the solder joint is unqualified. If the solder joint deformation is less than the preset deformation, it is determined that the quality of the solder joint is qualified. Since traditional automatic optical inspection can only perform static inspection after soldering is completed, it cannot monitor the quality changes during the soldering process in real time. By using high-precision sensors to obtain the displacement deformation and stress deformation at each solder joint in the thermal stress area, real-time monitoring of the soldering process can be achieved, which enables the quality of the solder joints to be judged immediately during the soldering process, and the soldering parameters to be dynamically adjusted according to the real-time data, thus avoiding the situation where problems cannot be corrected when they are discovered later. By analyzing multi-dimensional data such as the thermal stress, external dynamic stress, and deformation comprehensive index of each solder joint, the quality of the solder joints can be evaluated more accurately. By calculating the stress and deformation comprehensive index, the quality status of the solder joints can be analyzed from the perspectives of internal stress, deformation, etc., and potential defects in soldering can be predicted and discovered more precisely. The relationship between the deformation comprehensive index and the preset threshold can automatically trigger the adjustment of the soldering parameters, which makes the entire soldering process more automated, reducing the errors and lags of manual judgment and adjustment. The system can automatically optimize the soldering parameters according to the real-time data, improving the consistency and reliability of the soldering quality. By dynamically adjusting the soldering parameters, potential quality problems can be identified in advance during the soldering process, and the process parameters can be adjusted in real time to avoid the generation of unqualified solder joints. This preventive measure can effectively reduce the incidence of soldering quality problems.Improve the qualified rate of products. During the welding process, factors such as temperature change, thermal stress, and cooling rate will affect the quality of solder joints, and these factors may be complex and dynamically changing. Through multi-dimensional analysis (including thermal stress, deformation amount, stress distribution, etc.), the comprehensive influence of various factors can be comprehensively evaluated, thereby improving the adaptability to welding quality under complex working conditions. In addition to being affected by temperature and solder fluidity, the quality of solder joints may also be abnormally affected by factors such as shaking during the cooling process and changes in the external environment. However, through the comprehensive analysis of the deformation, thermal stress, and post-cooling deformation during the welding process, the present invention can comprehensively consider these influencing factors, and then realize automatic adjustment of welding parameters by combining real-time data acquisition and deformation analysis, avoid welding defects caused by external factors such as temperature and pressure, improve the stability and consistency of the quality of solder joints, and reduce the risk of unqualified solder joints.

[0094] In one embodiment, step S1 of constructing a dynamic temperature change curve graph according to the multiple continuous real-time temperatures includes:

[0095] S11. Obtain the parameter characteristics of each welding point, where the parameter characteristics include density, specific heat capacity, and thermal conductivity;

[0096] S12. Obtain the initial temperature and heat source power of each welding point, and calculate the heat source temperature change rate according to the heat source power, density, and specific heat capacity, where the calculation formula is: ; where R(WB) represents the heat source temperature change rate, R(GL) represents the heat source power, C(MD) represents the density, and C(BR) represents the specific heat capacity;

[0097] S13. Calculate the heat source diffusion rate according to the thermal conductivity, density, and specific heat capacity, where the calculation formula is: ; where R(KS) represents the heat source diffusion rate, R(DL) represents the thermal conductivity, C(MD) represents the density, and C(BR) represents the specific heat capacity;

[0098] S14. Obtain the second-order partial derivative of the X-axis temperature, the second-order partial derivative of the Y-axis temperature, and the second-order partial derivative of the Z-axis temperature of the corresponding welding point in the X-axis direction, Y-axis direction, and Z-axis direction according to the initial temperature;

[0099] S15. Obtain the temperature spatial change rate according to the second-order partial derivative of the X-axis temperature, the second-order partial derivative of the Y-axis temperature, and the second-order partial derivative of the Z-axis temperature;

[0100] S16. Obtain the time step according to the multiple continuous real-time temperatures, and calculate the real-time temperature of the welding point in the next continuous real-time temperature according to the time step, temperature spatial change rate, heat source diffusion rate, heat source temperature change rate, and initial temperature, where the calculation formula is: ; where, S(WD) represents the real-time temperature of the welding point in the next consecutive real-time temperature, C(WD) represents the initial temperature, S(BC) represents the time step, W(KB) represents the temperature spatial change rate, R(WB) represents the heat source temperature change rate, and R(KS) represents the heat source diffusion rate;

[0101] S17. Take time as the X-axis and temperature as the Y-axis to establish a time-temperature coordinate axis, and plot the initial temperature as the starting point on the time-temperature coordinate axis;

[0102] S18. Take the real-time temperature of the welding point corresponding to each time step as the connection point and plot it on the time-temperature coordinate axis, and connect the starting point and multiple connection points in sequence with a curve to obtain a dynamic temperature change curve graph.

[0103] As described in the above steps S11 - S18, among them, the calculation formulas for the heat source temperature change rate, the heat source temperature change rate, and the real - time temperature are all normalized for parameters in advance to eliminate the dimensional differences between different variables. The purpose is to ensure that all variables are on the same order of magnitude, so as to make the calculation more stable and effective. Among them, the heat source temperature change rate is the ratio between the heat source power and the product of the material density and specific heat capacity. This ratio represents the contribution of the heat source power to the temperature change per unit volume and is the temperature change rate caused by the heat source in the material. The temperature spatial change rate refers to the Laplace operator of the temperature of the welding point in the grid cell at each time step, that is, the second - order spatial derivative of the temperature, which describes the spatial change of the temperature field and represents how heat diffuses in space. Among them, the real - time temperature of the welding point in each next continuous real - time temperature is obtained through the above - mentioned calculation formula from the temperature of the welding point in its previous continuous real - time temperature. The present invention obtains the density, specific heat capacity, and thermal conductivity of the parameter characteristics of each welding point, obtains the initial temperature and heat source power of each welding point through the first continuous real - time temperature, calculates the heat source temperature change rate according to the heat source power, density, and specific heat capacity, calculates the heat source diffusion rate according to the thermal conductivity, density, and specific heat capacity, obtains the second - order partial derivative of the X - axis temperature, the second - order partial derivative of the Y - axis temperature, and the second - order partial derivative of the Z - axis temperature of the corresponding welding point in the X - axis direction, Y - axis direction, and Z - axis direction according to the initial temperature, obtains the temperature spatial change rate according to the sum of the second - order partial derivative of the X - axis temperature, the second - order partial derivative of the Y - axis temperature, and the second - order partial derivative of the Z - axis temperature, and obtains the time step through multiple continuous real - time temperatures. The present invention uses continuous real - time temperature to track the temperature change of the welding point during the welding process in real time. Through the real - time calculation of information such as temperature, heat source power, and thermal conductivity at each moment, the temperature distribution and change rate during the welding process can be obtained, so as to be able to monitor the abnormal welding parameters during the welding process and react in a timely manner. By obtaining the characteristic parameters such as density, specific heat capacity, and thermal conductivity of each welding point, the thermodynamic properties of the welding point can be analyzed in depth. These physical parameters can provide more comprehensive information on the thermal behavior of the solder joint, which helps to accurately predict the welding quality and discover possible defects. Calculating the heat source temperature change rate according to the heat source power, density, and specific heat capacity, and calculating the heat source diffusion rate according to the thermal conductivity, density, and specific heat capacity helps to analyze the heat transfer characteristics during the welding process. Through these calculations, the thermal behavior of the welding point can be better understood, and potential problems such as uneven heat source or over - heating can be discovered in a timely manner, thus effectively avoiding welding quality problems. According to the second - order partial derivatives of the temperature in the X - axis, Y - axis, and Z - axis directions, the spatial change rate of the welding point temperature can be calculated, thereby revealing the gradient change of the temperature field and helping to analyze whether there are temperature - uneven or abnormal regions in the welding point, and further guiding the optimization of the welding process. By calculating dynamic characteristics such as the temperature change rate and diffusion rate, some minor welding defects or uneven phenomena can be discovered earlier.It avoids the limitation of traditional automatic optical inspection that only static inspection of external defects of cooled solder joints can be carried out. Through dynamic analysis, the occurrence of defects can be prevented in advance, and the stability of welding quality can be improved. By combining high-precision thermal imaging images and detailed thermodynamic calculations, more accurate solder joint quality inspection results are provided. Calculate the real-time temperature of the solder joint in the next continuous real-time temperature according to the time step, temperature spatial change rate, heat source diffusion rate, heat source temperature change rate and initial temperature. By taking time as the X-axis and temperature as the Y-axis, establish a time-temperature coordinate axis, and plot the initial temperature as the starting point on the time-temperature coordinate axis. By plotting the real-time temperature of the solder joint corresponding to each time step as a connection point on the time-temperature coordinate axis, and connecting the starting point and multiple connection points in sequence through a curve, a dynamic temperature change curve graph is obtained. Since the traditional automatic optical inspection method can only perform static detection on the cooled solder joints after welding is completed, it cannot directly capture the dynamic changes (such as fluctuations in temperature, stress, etc.) that occur during the welding process. By calculating the real-time temperature based on dynamic factors such as time step, temperature spatial change rate, and heat source diffusion rate, and plotting the dynamic temperature change curve, the temperature change during the welding process can be monitored in real time, and the dynamic characteristics during welding can be captured. Such dynamic monitoring can help detect abnormalities that occur during the welding process, such as overheating or uneven temperature, and make timely responses. Through the generated time-temperature curve, the temperature change of the solder joint at different time steps can be clearly observed. This can not only help detect external defects of the solder joint, but also further evaluate the uniformity of temperature distribution and the stability of welding quality during the welding process. For example, too fast a temperature change rate may lead to welding defects, while uneven temperature distribution may affect the quality of welding. This method can comprehensively evaluate welding quality, not just limited to the external form. By calculating the real-time temperature change and plotting the dynamic temperature change curve graph, potential temperature abnormal areas during the welding process can be identified in advance. These abnormal areas may indicate potential problems during the welding process, such as local overheating, heat accumulation or uneven cooling, etc. These problems usually need to be detected through temperature changes, while the automatic optical inspection method may not be able to capture these dynamic changes. The real-time temperature data enables problems to be discovered during the welding process, rather than waiting until after welding is completed for analysis. By monitoring the dynamic changes in temperature, the welding process can be more finely controlled. Based on the real-time data feedback of temperature, the welding operation can be adjusted during the process to avoid welding defects caused by too fast or uneven temperature changes. Compared with traditional welding quality inspection, monitoring the dynamic changes in temperature helps to immediately adjust the preset welding parameters, improving the stability and reliability of welding. The dynamic temperature change curve provides rich data and can more objectively evaluate welding quality. Through the numerical calculation of temperature changes, the evaluation of welding quality no longer depends on manual visual inspection, but the quality evaluation result of the solder joint is obtained through accurate numerical data.Data-driven evaluation methods are more objective and reliable, avoiding the biases and errors that may be brought about by manual inspection. Through real-time dynamic temperature monitoring and time-temperature curve plotting, the accuracy of solder joint quality inspection can be effectively improved. Dynamic monitoring not only avoids the information lag caused by static inspection but also makes the inspection results more comprehensive. Potential soldering defects can be accurately predicted through the temperature change curve, thereby improving the quality and production efficiency of the soldering process.

[0104] In one embodiment, step S2 of obtaining the corresponding thermal stress according to each of the temperature gradient distribution data and determining the thermal stress region according to the thermal stress includes:

[0105] S21. Obtain the temperature change rate in the vertical direction and the temperature change rate in the horizontal direction according to each of the temperature gradient distribution data;

[0106] S22. Obtain the coefficient of thermal expansion and elastic modulus of each solder joint, and obtain the corresponding vertical strain force according to each of the coefficient of thermal expansion and the temperature change rate in the vertical direction;

[0107] S23. Obtain the corresponding horizontal strain force according to each of the coefficient of thermal expansion and the temperature change rate in the horizontal direction, and obtain the corresponding Poisson's ratio according to each of the horizontal strain force and the vertical strain force;

[0108] S24. Calculate the thermal stress at the corresponding solder joint according to each of the Poisson's ratio, coefficient of thermal expansion, elastic modulus, and temperature gradient distribution data, where the calculation formula is: ; where R(YL) represents the thermal stress, R(PZ) represents the coefficient of thermal expansion, W(TF) represents the temperature gradient distribution data, T(XM) represents the elastic modulus, and B(SB) represents Poisson's ratio;

[0109] S25. Determine whether the thermal stress is greater than a preset stress;

[0110] If the thermal stress is greater than the preset stress, determine the solder joint corresponding to the thermal stress as the thermal stress region;

[0111] If the thermal stress is not greater than the preset stress, determine the solder joint corresponding to the thermal stress as the non-thermal stress region.

[0112] As described in the above steps S21 - S25, the calculation formula for calculating the thermal stress at the corresponding welding point based on the Poisson's ratio, coefficient of thermal expansion, elastic modulus, and temperature gradient distribution data needs to normalize the parameters in advance to eliminate the dimensional differences between different variables. The purpose is to ensure that all variables are on the same order of magnitude, thereby making the calculation more stable and effective. The present invention obtains the temperature change rate in the vertical direction and the temperature change rate in the horizontal direction through each temperature gradient distribution data, obtains the coefficient of thermal expansion and elastic modulus of each welding point, obtains the corresponding vertical strain force according to each coefficient of thermal expansion and the temperature change rate in the vertical direction, obtains the corresponding horizontal strain force according to each coefficient of thermal expansion and the temperature change rate in the horizontal direction, obtains the corresponding Poisson's ratio according to each horizontal strain force and vertical strain force, calculates the thermal stress at the corresponding welding point according to each Poisson's ratio, coefficient of thermal expansion, elastic modulus, and temperature gradient distribution data, and determines whether the thermal stress is greater than the preset stress. If the thermal stress is greater than the preset stress, the welding point corresponding to the thermal stress is determined as the thermal stress area; if the thermal stress is not greater than the preset stress, the welding point corresponding to the thermal stress is determined as the non - thermal stress area. Since the automatic optical inspection method can only detect static defects after welding is completed and cannot directly capture the dynamic changes occurring during the welding process.The method of calculating thermal stress through temperature gradient data can monitor in real time the stress changes that may occur during the welding process, especially the strain caused by thermal expansion and temperature gradient. This can identify the stress concentration areas generated during the welding process in advance, and avoid potential defects in the welds due to uneven stress during the welding process. By calculating the thermal stress of each welding point and comparing it with the preset stress value, it can accurately identify which welding points may deform or break due to excessive thermal stress. This method based on stress analysis can supplement traditional appearance inspection, reduce the possibility of missed inspections and misjudgments, and ensure that the welding quality is under monitoring throughout the entire welding process. The method of inferring thermal stress through physical parameters such as thermal expansion coefficient and elastic modulus avoids the interference of the external environment on the test results, and can more objectively and accurately evaluate the quality of the welding points. Real-time calculation of thermal stress and timely judgment of whether it exceeds the safety range can effectively prevent cracks in solder joints or other structural damage caused by excessive thermal stress. This can provide a scientific basis for defect prediction in the welding process, help improve the control level of welding quality, avoid the need for later repairs, and thus improve production efficiency and product reliability. By combining multiple physical quantities such as temperature gradient distribution, thermal expansion coefficient, elastic modulus, Poisson's ratio, etc., it can comprehensively reflect the behavior of solder joints under thermal stress, rather than relying solely on a single parameter. This method provides a more multidimensional and comprehensive quality assessment, and can better handle the various factors that may arise in complex welding processes, thereby supplementing traditional automatic optical inspection and providing a more comprehensive means of welding quality detection, which can greatly improve quality assurance in the welding process and ensure product reliability and safety.

[0113] In one embodiment, the step S3 of obtaining the displacement deformation and stress deformation at each welding point in each thermal stress area by a high-speed sensor, and obtaining the corresponding external dynamic deformation according to each displacement deformation and stress deformation, comprises:

[0114] S31, obtaining an initial horizontal coordinate, an initial vertical coordinate, and an initial vertical coordinate of each welding point in each thermal stress region by a high-speed sensor;

[0115] S32, obtaining the real-time horizontal coordinate, real-time vertical coordinate and real-time vertical coordinate of each welding point in each thermal stress area at each preset time point through a high-speed sensor;

[0116] S33, according to each of the real-time horizontal coordinate, real-time vertical coordinate, real-time vertical coordinate, initial horizontal coordinate, initial vertical coordinate and initial vertical coordinate, the displacement deformation of the corresponding welding point is obtained, and the calculation formula is: ; where, W(BX) represents the displacement deformation amount, S(HB) represents the real-time abscissa, C(HB) represents the initial abscissa, S(ZB) represents the real-time ordinate, C(ZB) represents the initial ordinate, S(CB) represents the real-time vertical coordinate, and C(CB) represents the initial vertical coordinate;

[0117] S34. Obtain the thermal expansion coefficient, temperature gradient distribution data, and initial length of each welding point in each thermal stress region;

[0118] S35. Obtain the stress deformation amount of the corresponding welding point according to each of the thermal expansion coefficient, temperature gradient distribution data, and initial length, where the calculation formula is: ; where, Y(BX) represents the stress deformation amount, R(PZ) represents the thermal expansion coefficient, C(CD) represents the initial length, and W(TF) represents the temperature gradient distribution data;

[0119] S36. Obtain the corresponding external dynamic deformation amount according to each of the stress deformation amounts and displacement deformation amounts.

[0120] As described in the above steps S31 - S36, the calculation formula for obtaining the stress deformation amount of the corresponding welding point based on the coefficient of thermal expansion, temperature gradient distribution data, and initial length requires prior normalization of the parameters to eliminate the dimensional differences between different variables. The purpose is to ensure that all variables are on the same order of magnitude, thereby making the calculation more stable and effective. In the present invention, a high-speed sensor is used to obtain the initial abscissa, initial ordinate, and initial vertical coordinate of each welding point in each thermal stress area, as well as the real-time abscissa, real-time ordinate, and real-time vertical coordinate of each welding point in each thermal stress area at each preset time point. The displacement deformation amount of the corresponding welding point is obtained based on each real-time abscissa, real-time ordinate, real-time vertical coordinate, initial abscissa, initial ordinate, and initial vertical coordinate. The stress deformation amount of the corresponding welding point is calculated through the coefficient of thermal expansion, temperature gradient distribution data, and initial length of each welding point in each thermal stress area. The corresponding external dynamic deformation amount is obtained based on each stress deformation amount and displacement deformation amount. By using a high-speed sensor to obtain the coordinate data of each welding point in real time, the physical changes such as thermal stress and displacement deformation during the welding process can be dynamically monitored. By continuously tracking the real-time position of each welding point, potential defects or abnormalities can be discovered during the welding process, and adjustments or corrections can be made in a timely manner. Using the real-time coordinates and initial coordinate data, the displacement deformation amount of the welding point can be accurately calculated. Moreover, by combining the coefficient of thermal expansion, temperature gradient distribution data, and initial length, the stress deformation amount of the welding point can be further calculated. This method takes into account the influencing factors of temperature and stress and can more accurately reflect the welding quality than simply relying on visual inspection. Especially for those welding points where no obvious defects can be seen on the surface, these problems can be early warned by detecting the real-time thermal stress and displacement changes during the welding process, thereby avoiding quality problems caused by dynamic changes during the welding process, such as possible thermal cracks, incomplete welding, material deformation, etc., which can be discovered and repaired earlier through this method. The real-time data obtained through this method can more accurately reflect the stress state, thermal effect, and deformation trend during the welding process, and can more accurately control the welding quality. This helps to reduce the quality fluctuations caused by unstable factors and improve the stability and consistency of the overall welding. By automatically obtaining and processing real-time data through a high-speed sensor and a data analysis system, manual intervention can be greatly reduced, and errors can be reduced through data analysis, improving the accuracy and reliability of detection. This not only improves the controllability of welding quality but also optimizes the stability and consistency of the entire welding process, thereby reducing the defect rate and improving the production efficiency and product reliability.

[0121] In one embodiment, step S4 of obtaining the corresponding external dynamic stress according to each of the external dynamic deformation amounts and obtaining the corresponding total stress according to each of the external dynamic stresses and thermal stresses includes:

[0122] S41. Perform a first-order time derivative process on each of the external dynamic deformation amounts to obtain the deformation rate of change.

[0123] S42. Perform a second-order time derivative process on each of the deformation rates of change to obtain the deformation acceleration.

[0124] S43. Obtain the elastic modulus and density of the corresponding welding points according to each of the external dynamic deformation amounts, and obtain the corresponding deformation stress according to the product of each of the densities and the deformation acceleration.

[0125] S44. Obtain the corresponding inertial force according to the product of each of the external dynamic deformation amounts and the elastic modulus, and obtain the corresponding external dynamic stress according to the product of each of the inertial forces and the deformation stress.

[0126] S45. Obtain the thermal stress of each welding point, and obtain the corresponding total stress according to the product of each of the thermal stresses and the external dynamic stresses.

[0127] As described in the above steps S41 - S45, wherein the corresponding inertial force is obtained by multiplying the external dynamic deformation amount by the elastic modulus, which represents the inertial force caused by vibration or fluctuation per unit volume of the material, that is, the internal force generated by the change in acceleration of the material. The corresponding deformation stress is obtained by multiplying the density by the acceleration of the deformation amount, which represents the stress of the material at a certain time point (related to the elastic modulus and strain of the material). The calculation formulas of the above inertial force and deformation stress need to normalize the parameters in advance to eliminate the dimensional differences between different variables. The purpose is to ensure that all variables are on the same order of magnitude, so as to make the calculation more stable and effective. In the present invention, the deformation rate of change is obtained by performing a first-order time derivative process on each external dynamic deformation amount, the acceleration of the deformation amount is obtained by performing a second-order time derivative process on each deformation rate of change, the elastic modulus and density of the corresponding welding point are obtained through each external dynamic deformation amount, the corresponding deformation stress is obtained according to the product of each density and the acceleration of the deformation amount, the corresponding inertial force is obtained according to the product of each external dynamic deformation amount and the elastic modulus, the corresponding external dynamic stress is obtained according to each inertial force and deformation stress, and the corresponding total stress is obtained according to each thermal stress and external dynamic stress. Since the traditional automatic optical inspection method can only detect the solder joints in the cooled state after welding, this may ignore the important changes during the welding process. The present invention can capture the dynamic changes of the deformation amount, acceleration, and stress in real time during the welding process, so as to more accurately reflect the quality problems during the welding process. For example, problems such as overheating, excessive deformation, or stress concentration that may occur during the welding process can be detected in time, so that corrective measures can be taken earlier. By performing a second-order time derivative process on the deformation rate of change and acceleration, a more refined dynamic behavior analysis can be obtained. This not only considers the geometric shape changes of the solder joints, but also reflects the changes in the physical state during the welding process, such as the influence of thermal stress and external dynamic stress on the solder joints. This comprehensive detection method can provide higher accuracy than the optical detection method, especially at the microscopic level of welding quality. Factors such as deformation, thermal stress, and dynamic stress that may occur during the welding process have an important impact on the formation of solder joints. Through dynamic stress analysis and the calculation of inertial force, it is possible to more comprehensively evaluate whether potential defects such as microscopic cracks and solder joint loosening may occur in the solder joints. This helps to detect problems immediately during the welding process, reduce the omission of defects, and avoid welding defects that cannot be detected by traditional optical inspection. Considering external dynamic factors (such as inertial force, acceleration, thermal stress, etc.) can not only improve the real-time monitoring ability of the quality of solder joints, but also provide data support for the optimization of the welding process. According to the information such as the detected deformation stress, inertial force, and total stress, the welding process can be adjusted in time, thereby improving the welding quality and stability, and contributing to improving the overall welding quality and production efficiency.

[0128] In one embodiment, step S5 of obtaining the corresponding deformation comprehensive index according to each total stress includes:

[0129] S51. Obtain the modulus characteristics of each welding point, where the modulus characteristics include elastic modulus and viscosity coefficient;

[0130] S52. Obtain the corresponding elastic strain force according to each elastic modulus and the total stress;

[0131] S53. Obtain the yield strength of each welding point, and determine whether the total stress is greater than the yield strength;

[0132] If the total stress is greater than the yield strength, obtain the plastic modulus of the corresponding welding point, and obtain the corresponding plastic strain increment rate according to the ratio between the difference between each total stress and elastic strain force and the plastic modulus;

[0133] S54. Calculate the corresponding plastic strain force according to each plastic strain increment rate, total stress, elastic strain force and elastic modulus, where the calculation formula is: ; where S(YL) represents plastic strain force, Z(YL) represents total stress, T(YL) represents elastic strain force, T(ML) represents elastic modulus, and S(ZS) represents plastic strain increment rate;

[0134] S55. Obtain the corresponding viscous strain force according to each viscosity coefficient and the total stress, and calculate the deformation comprehensive index according to each viscous strain force, elastic strain force and plastic strain force, where the calculation formula is: ; where X(ZS) represents the deformation comprehensive index, α represents the weight of the viscous strain force, N(YL) represents the viscous strain force, β represents the weight of the elastic strain force, T(YL) represents the elastic strain force, γ represents the weight of the plastic strain force, and S(YL) represents the plastic strain force.

[0135] As described in the above steps S51 - S55, the calculation formulas of plastic strain force and deformation comprehensive index need to normalize the parameters in advance to eliminate the dimensional differences between different variables. The purpose is to ensure that all variables are in the same order of magnitude, so as to make the calculation more stable and effective. The present invention obtains the elastic modulus and viscosity coefficient of the modulus characteristics of each welding point, obtains the corresponding elastic strain force according to each elastic modulus and the total stress, obtains the yield strength of each welding point, and judges whether the total stress is greater than the yield strength. If the total stress is greater than the yield strength, the corresponding plastic modulus of the welding point is obtained, and the corresponding plastic strain increment rate is obtained according to the ratio between the difference of each total stress and elastic strain force and the plastic modulus. The corresponding plastic strain force is calculated according to each plastic strain increment rate, total stress, elastic strain force and elastic modulus. The corresponding viscous strain force is obtained according to each viscosity coefficient and total stress, and the corresponding deformation comprehensive index is calculated according to each viscous strain force, elastic strain force and plastic strain force. By obtaining information such as the elastic modulus, viscosity coefficient and total stress of each welding point, the dynamic behavior during the welding process can be monitored in real time, which enables potential problems such as stress overload, yield or plastic deformation to be captured at any moment during the welding. Through the calculation of the elastic modulus, plastic modulus and viscosity coefficient, combined with the relationship between the total stress and strain force, a more accurate analysis of the internal stress state of the welding point can be carried out. When the total stress exceeds the yield strength, the plastic strain of the welding point can be obtained through the calculation of the plastic modulus and strain increment rate, which further helps to judge whether it will cause potential defects (such as cracks, deformation, etc.). In this way, the mechanical behavior during the welding process can be deeply understood, providing more material-level information than simple optical inspection. During the welding process, the welding point may enter the plastic deformation stage due to excessive stress, and even cause fatigue cracks. By calculating the plastic strain increment rate, plastic strain force, etc., the risk of plastic deformation and cracks in the welding point can be predicted in real time, especially when the stress exceeds the yield strength. This is crucial for improving the predictability and preventive control of welding quality. The traditional optical inspection method may miss defects that are not visible on the surface, especially some internal defects such as small plastic deformations and thermal cracks.By dynamically monitoring parameters such as stress, strain, and plastic force, potential problems that may not be apparent on the surface can be effectively detected. The comprehensive index of dynamic stress and deformation can reveal the influence of different types of stress on the welding points during the welding process, helping to discover internal defects that cannot be identified by optical methods. By combining different mechanical parameters such as elastic strain force, plastic strain force, and viscous strain force, the quality of the welding points can be analyzed more comprehensively. Dynamically calculating the comprehensive index of these parameters can provide a more accurate and multi-dimensional quality assessment than traditional detection methods. For complex welding points (such as multi-layer welding or solder joints with special material requirements), this method can significantly improve the accuracy of quality control. Through real-time dynamic analysis, not only can immediate problems during the welding process be discovered, but also by modeling the stress and strain state of the welding points, the future performance of the welding quality can be predicted. Based on the comprehensive analysis of stress and strain force, the welding parameters can be optimized, thereby improving the overall welding quality and reducing the later rework rate and failure rate. By monitoring parameters such as plastic modulus and strain rate, excessive plastic deformation can be avoided, thereby reducing the residual stress after welding and preventing cracks or deformation, ensuring the strength and durability of the welded joints. For high-precision and high-volume welding processes (such as electronic component manufacturing, automotive parts welding, etc.), by combining dynamic analysis of elastic modulus, plastic modulus, viscosity coefficient, etc., real-time feedback can be combined with automatic control to provide fine adjustments at each stage of the welding process. This not only improves the intelligence and automation of the welding process but also ensures the stability of production efficiency and quality.

[0136] This application also provides an on-line detection system for the quality of solder joints of a circuit component, including:

[0137] A construction module, configured to obtain continuous real-time temperatures at multiple consecutive moments of each welding point of the circuit component during the welding process under preset welding parameters, and construct a dynamic temperature change curve graph based on the multiple continuous real-time temperatures;

[0138] A determination module, configured to extract temperature gradient distribution data of each welding point at multiple time nodes according to the dynamic temperature change curve graph, and determine a thermal stress region according to each temperature gradient distribution data;

[0139] A first acquisition module, configured to acquire a displacement deformation amount and a stress deformation amount at each welding point in each thermal stress region through a high-speed sensor, and acquire a corresponding external dynamic deformation amount according to each displacement deformation amount and stress deformation amount;

[0140] A second acquisition module, configured to acquire a corresponding external dynamic stress according to each external dynamic deformation amount, and acquire a total stress according to each external dynamic stress and thermal stress;

[0141] The first judgment module is used to obtain a deformation comprehensive index according to each of the total stresses and judge the relationship between the deformation comprehensive index and a preset threshold range;

[0142] If the deformation comprehensive index is less than the lower limit value of the preset threshold range, it is determined that the quality of the welding point is unqualified;

[0143] If the deformation comprehensive index is within the preset threshold range, obtain the solder joint radius after cooling of the corresponding welding point, and obtain the corresponding moment of inertia according to each of the solder joint radii;

[0144] The second judgment module is used to obtain the corresponding solder joint deformation according to each of the moments of inertia and solder joint radii, and judge whether the solder joint deformation is less than a preset deformation;

[0145] If the solder joint deformation is not less than the preset deformation, it is determined that the quality of the welding point is unqualified;

[0146] If the solder joint deformation is less than the preset deformation, it is determined that the quality of the welding point is qualified.

[0147] In one embodiment, the determination module includes:

[0148] The first acquisition unit is used to obtain the vertical direction temperature change rate and the horizontal direction temperature change rate according to each of the temperature gradient distribution data;

[0149] The second acquisition unit is used to obtain the thermal expansion coefficient and elastic modulus of each welding point, and obtain the corresponding vertical strain force according to each of the thermal expansion coefficients and the vertical direction temperature change rate;

[0150] The third acquisition unit is used to obtain the corresponding horizontal strain force according to each of the thermal expansion coefficients and the horizontal direction temperature change rate, and obtain the corresponding Poisson's ratio according to each of the horizontal strain forces and the vertical strain forces;

[0151] The fourth acquisition unit is used to obtain the thermal stress at the corresponding welding point according to each of the Poisson's ratios, thermal expansion coefficients, elastic moduli and temperature gradient distribution data;

[0152] The determination unit is used to judge whether the thermal stress is greater than a preset stress;

[0153] If the thermal stress is greater than the preset stress, the welding point corresponding to the thermal stress is determined as the thermal stress area;

[0154] If the thermal stress is not greater than the preset stress, the welding point corresponding to the thermal stress is determined as the non-thermal stress area.

[0155] It should be noted that each module and unit in the on-line detection system for the quality of circuit component solder joints corresponds one by one to the steps in the on-line detection method for the quality of circuit component solder joints.

[0156] As shown Figure 3 in the figure, the present application further provides a computer device, which may be a server, and its internal structure may be as shown Figure 3 in the figure. The computer device includes a processor, a memory, a network interface, and a database connected through a system bus. Among them, the processor of the computer design is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store all the data required for the process of the online detection method for the solder joint quality of circuit components. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, it realizes the online detection method for the solder joint quality of circuit components.

[0157] Those skilled in the art can understand that Figure 3 the structure shown in is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied.

[0158] An embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it realizes any one of the above online detection methods for the solder joint quality of circuit components.

[0159] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, storage, database, or other medium provided in this application and used in the embodiments can include non-volatile and / or volatile memories. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (SSRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and Rambus dynamic RAM (RDRAM), etc.

[0160] It should be noted that in this article, the terms "include", "comprise", or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, apparatus, article, or method that includes a series of elements includes not only those elements but also other elements not expressly listed, or elements that are inherent to such process, apparatus, article, or method. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, apparatus, article, or method that includes such element.

[0161] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural or equivalent process transformation made by using the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present invention.

Claims

1. A method for online detection of solder joint quality of circuit components, characterized in that: include: Acquire the continuous real-time temperature of each welding point of the circuit component at multiple continuous moments during the welding process under preset welding parameters, and construct a dynamic temperature change curve diagram according to the multiple continuous real-time temperatures; Extracting temperature gradient distribution data of each welding point at multiple time nodes according to the dynamic temperature change curve diagram, and obtaining a vertical temperature change rate and a horizontal temperature change rate according to each temperature gradient distribution data; Obtaining the thermal expansion coefficient and elastic modulus of each welding point, and obtaining the corresponding vertical strain force according to each thermal expansion coefficient and vertical temperature change rate; Obtaining a corresponding horizontal strain force according to each of the thermal expansion coefficients and the temperature change rate in the horizontal direction, and obtaining a corresponding Poisson's ratio according to each of the horizontal strain force and the vertical strain force; Obtaining thermal stress at a corresponding welding point according to each of the Poisson's ratio, thermal expansion coefficient, elastic modulus and temperature gradient distribution data; Determining whether the thermal stress is greater than a preset stress; If the thermal stress is greater than the preset stress, the welding point corresponding to the thermal stress is determined as a thermal stress area; If the thermal stress is not greater than the preset stress, the welding point corresponding to the thermal stress is determined as a non-thermal stress area; Obtain the displacement deformation and stress deformation at each welding point in each thermal stress area by means of a high-speed sensor, and obtain the corresponding external dynamic deformation according to each displacement deformation and stress deformation; Obtaining a corresponding external dynamic stress according to each of the external dynamic deformations, and obtaining a total stress according to each of the external dynamic stresses and the thermal stress; Obtaining a deformation comprehensive index according to each of the total stresses, and determining a relationship between the deformation comprehensive index and a preset threshold range; If the deformation comprehensive index is greater than the upper limit of the preset threshold value interval, the quality of the welding point is determined to be unqualified, and the preset welding parameters are reduced in real time according to the deformation comprehensive index; If the deformation comprehensive index is less than the lower limit of the preset threshold value interval, the quality of the welding point is determined to be unqualified, and the preset welding parameters are increased in real time according to the deformation comprehensive index; If the deformation comprehensive index is within the preset threshold range, the radius of the corresponding welding point after cooling is obtained, and the corresponding moment of inertia is obtained according to each welding point radius; Obtaining a corresponding solder joint deformation according to each of the moments of inertia and the solder joint radius, and determining whether the solder joint deformation is less than a preset deformation; If the deformation of the welding point is not less than the preset deformation, the welding point is judged to be unqualified; If the deformation of the welding point is smaller than the preset deformation, the welding point is judged to be of qualified quality.

2. The method for online detection of solder joint quality of circuit components according to claim 1, characterized in that: The step of constructing a dynamic temperature change curve diagram according to the plurality of continuous real-time temperatures comprises: Acquire parameter characteristics of each welding point, wherein the parameter characteristics include density, specific heat capacity and thermal conductivity; Obtaining the initial temperature and heat source power of each welding point, and obtaining the heat source temperature change rate according to the heat source power, density and specific heat capacity; Obtaining a heat source diffusivity according to the thermal conductivity, density and specific heat capacity; According to the initial temperature, the second-order partial derivative of the X-axis temperature, the second-order partial derivative of the Y-axis temperature, and the second-order partial derivative of the Z-axis temperature of the corresponding welding point in the X-axis direction, the Y-axis direction, and the Z-axis direction are obtained; Obtaining the temperature spatial change rate according to the second-order partial derivative of the X-axis temperature, the second-order partial derivative of the Y-axis temperature, and the second-order partial derivative of the Z-axis temperature; Acquire a time step according to the plurality of continuous real-time temperatures, and acquire a real-time temperature of a welding point in a corresponding next continuous real-time temperature according to the time step, the temperature spatial change rate, the heat source diffusion rate, the heat source temperature change rate and the initial temperature; With time as the X-axis and temperature as the Y-axis, a time-temperature coordinate axis is established, and the initial temperature is plotted as the starting point on the time-temperature coordinate axis; The real-time temperature of the welding point corresponding to each time step is plotted as a connection point on the time-temperature coordinate axis, and the starting point and multiple connection points are sequentially connected through curves to obtain a dynamic temperature change curve diagram.

3. The method for online detection of solder joint quality of circuit components according to claim 1, characterized in that: The step of obtaining the displacement deformation and stress deformation at each welding point in each thermal stress area by a high-speed sensor, and obtaining the corresponding external dynamic deformation according to each displacement deformation and stress deformation, comprises: Obtaining the initial abscissa, initial ordinate and initial vertical coordinate of each welding point in each thermal stress zone by means of a high-speed sensor; The real-time horizontal coordinate, real-time vertical coordinate and real-time vertical coordinate of each welding point in each thermal stress area at each preset time point are obtained by high-speed sensors; Obtain the displacement deformation of the corresponding welding point according to each of the real-time horizontal coordinate, the real-time vertical coordinate, the real-time vertical coordinate, the initial horizontal coordinate, the initial vertical coordinate and the initial vertical coordinate; Obtain the thermal expansion coefficient, temperature gradient distribution data and initial length of each welding point in each thermal stress area; Obtaining the stress deformation of the corresponding welding point according to each of the thermal expansion coefficients, temperature gradient distribution data and initial length; The corresponding external dynamic deformation is obtained according to each of the stress deformation and displacement deformation.

4. The method for online detection of solder joint quality of circuit components according to claim 1, characterized in that: The step of obtaining the corresponding external dynamic stress according to each external dynamic deformation, and obtaining the total stress according to each external dynamic stress and thermal stress, comprises: Performing first-order time derivative processing on each of the external dynamic deformations to obtain a deformation change rate; Performing second-order time derivative processing on each of the deformation change rates to obtain deformation acceleration; Obtaining the elastic modulus and density of the corresponding welding point according to each of the external dynamic deformations, and obtaining the corresponding deformation stress according to each of the density and deformation acceleration; Obtaining a corresponding inertial force according to each of the external dynamic deformation amounts and the elastic modulus, and obtaining a corresponding external dynamic stress according to each of the inertial force and the deformation stress; The thermal stress of each welding point is obtained, and the total stress is obtained according to each thermal stress and the external dynamic stress.

5. The method for online detection of solder joint quality of circuit components according to claim 1, characterized in that: The step of obtaining a comprehensive deformation index according to each of the total stresses comprises: Obtaining a modulus characteristic of each welding point, wherein the modulus characteristic includes an elastic modulus and a viscosity coefficient; Obtaining corresponding elastic strain force according to each of the elastic moduli and the total stress; Obtaining the yield strength of each welding point, and determining whether the total stress is greater than the yield strength; If the total stress is greater than the yield strength, the plastic modulus of the corresponding welding point is obtained, and the corresponding plastic strain increment rate is obtained according to each of the plastic modulus, elastic strain force and total stress; Obtaining corresponding plastic strain force according to each of the plastic strain increment rates, total stress, elastic strain force and elastic modulus; The corresponding viscous strain force is obtained according to each of the viscosity coefficients and the total stress, and the deformation comprehensive index is obtained according to each of the viscous strain force, the elastic strain force and the plastic strain force.

6. An online detection system for the quality of solder joints of circuit components, characterized in that: include: A construction module is used to obtain the continuous real-time temperature of each welding point of the circuit component during the welding process under preset welding parameters at multiple consecutive moments, and to construct a dynamic temperature change curve diagram according to the multiple continuous real-time temperatures; A determination module, used to extract the temperature gradient distribution data of each welding point at multiple time nodes according to the dynamic temperature change curve diagram, and obtain the vertical temperature change rate and the horizontal temperature change rate according to each of the temperature gradient distribution data; Obtaining the thermal expansion coefficient and elastic modulus of each welding point, and obtaining the corresponding vertical strain force according to each thermal expansion coefficient and vertical temperature change rate; Obtaining a corresponding horizontal strain force according to each of the thermal expansion coefficients and the temperature change rate in the horizontal direction, and obtaining a corresponding Poisson's ratio according to each of the horizontal strain force and the vertical strain force; Obtaining thermal stress at a corresponding welding point according to each of the Poisson's ratio, thermal expansion coefficient, elastic modulus and temperature gradient distribution data; Determining whether the thermal stress is greater than a preset stress; If the thermal stress is greater than the preset stress, the welding point corresponding to the thermal stress is determined as a thermal stress area; If the thermal stress is not greater than the preset stress, the welding point corresponding to the thermal stress is determined as a non-thermal stress area; A first acquisition module is used to acquire the displacement deformation and stress deformation at each welding point in each thermal stress area through a high-speed sensor, and acquire the corresponding external dynamic deformation according to each displacement deformation and stress deformation; A second acquisition module, used for acquiring the corresponding external dynamic stress according to each of the external dynamic deformations, and acquiring the total stress according to each of the external dynamic stresses and the thermal stress; A first judgment module, used for obtaining a deformation comprehensive index according to each of the total stresses, and judging a relationship between the deformation comprehensive index and a preset threshold interval; If the deformation comprehensive index is greater than the upper limit of the preset threshold value interval, the quality of the welding point is determined to be unqualified, and the preset welding parameters are reduced in real time according to the deformation comprehensive index; If the deformation comprehensive index is less than the lower limit of the preset threshold value interval, the quality of the welding point is determined to be unqualified, and the preset welding parameters are increased in real time according to the deformation comprehensive index; If the deformation comprehensive index is within the preset threshold range, the radius of the corresponding welding point after cooling is obtained, and the corresponding moment of inertia is obtained according to each welding point radius; A second judgment module is used to obtain a corresponding solder joint deformation according to each of the moments of inertia and the solder joint radius, and to judge whether the solder joint deformation is less than a preset deformation; If the deformation of the welding point is not less than the preset deformation, the welding point is judged to be unqualified; If the deformation of the welding point is smaller than the preset deformation, the welding point is judged to be of qualified quality.

7. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 5 are implemented.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 5 are implemented.

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