Spot welding optimization method and system based on spacing constraint

Abstract

The invention relates to the technical field of spot welding optimization, in particular to a spot welding optimization method and system based on spacing constraint, and the method comprises the following steps: obtaining welding current flow direction data in the manufacturing of a safety box body, analyzing the distribution condition of current between welding spots, monitoring the surface and surrounding temperatures of the welding spots, and analyzing the heat-conducting property of metal. And identifying the energy diffusion state between the welding spots to obtain the energy distribution characteristics of the welding spots. According to the method, the layout and spacing of the welding spots are adjusted through the heat conduction performance of metal of the safety box body, the stability and consistency of the welding process are further improved, material stress and deformation caused by uneven heating are reduced, temperature changes after welding are analyzed, the welding sequence and path can be optimized, the overheating risk is reduced, and the welding quality is improved. The overall strength and durability of the structure are improved, the welding quality and efficiency are remarkably improved, and the structure is particularly suitable for complex assemblies and advanced materials in the high-standard production environment.

Description

Technical Field

[0001] The present invention relates to the technical field of spot welding optimization, and in particular to a spot welding optimization method and system based on spacing constraints. Background Art

[0002] The field of spot welding technology encompasses joining techniques for metal materials, particularly in manufacturing and industry, used to secure metal pieces together in different parts or assemblies. This technique uses an electric current to generate heat at contact points, causing localized melting of the metal at these points, creating a weld to connect the metal parts. Key to spot welding technology lies in the selection of welding parameters (such as current, pressure, and time), as well as how these parameters are used to optimize the quality and efficiency of the weld. This technique is an integral part of many industrial applications, particularly in production lines where metal parts must be joined quickly and efficiently.

[0003] The spacing-constrained spot welding optimization method improves the stability and consistency of the welding process by adjusting and optimizing the spacing between spot welds. The patent focuses on how to precisely control spot weld spacing to adapt to different industrial application requirements, including component positioning, welding force, and heat distribution. This method is particularly suitable for high-standard production environments that require precise control of welding quality and efficiency, such as when using advanced materials or complex component designs. This approach allows for greater flexibility in adapting to different production needs while improving production efficiency and welding quality consistency.

[0004] Existing spot welding technology has certain limitations when it comes to handling fine solder joint layouts and controlling the welding process. Conventional methods cannot achieve a high degree of customization in controlling welding current and pressure, making it difficult to ensure welding quality in complex or high-precision applications. This technical limitation leads to uneven heat distribution between solder joints, affecting the mechanical properties and durability of the welded joints. Insufficient existing technologies in solder joint temperature management and energy diffusion monitoring can cause material damage or structural failure during welding, especially in components operating in high-temperature or high-pressure environments. Improvements in these areas can significantly improve the accuracy of welding operations and the effectiveness of material application, reducing scrap rates and maintenance costs in production. Summary of the Invention

[0005] In order to solve the limitations of the existing technology in handling fine solder joint layout and controlling the welding process, conventional methods cannot achieve high customization in the control of welding current and pressure, resulting in difficulty in ensuring welding quality in complex or high-precision applications. This technical limitation leads to uneven heat distribution between solder joints, affecting the mechanical properties and durability of the welded joints. The shortcomings of the existing technology in solder joint temperature management and energy diffusion monitoring cause technical problems such as material damage or structural failure during welding. The embodiments of the present invention provide a spot welding optimization method and system based on spacing constraints. The technical solution is as follows:

[0006] In one aspect, a spot welding optimization method based on spacing constraints is provided, the method comprising:

[0007] S1: Obtain welding current flow data during safe cabinet production, analyze the current distribution between welds, monitor the surface temperature of and around welds, analyze the thermal conductivity of metals, identify the energy diffusion state between welds, and obtain the energy distribution characteristics of welds;

[0008] S2: Using the energy distribution characteristics of the weld points, referring to the welded plates of the safe body, analyzing the heat-affected zones between the weld points, identifying the heat transfer conditions under different plate thicknesses, adjusting the weld point layout and spacing based on the material properties, and obtaining a weld point spacing adjustment result;

[0009] S3: Using the solder point spacing adjustment result, collecting solder point temperature change data after the spacing adjustment, calculating the heat transfer rate between adjacent solder points with reference to the thermal diffusion rate, thickness and ambient temperature of the metal material, determining the heat accumulation between the solder points, and obtaining a solder point temperature decay curve;

[0010] S4: Analyze the optimal welding sequence of adjacent solder joints through the solder joint temperature attenuation curve, identify the heat conduction path of the solder joints with reference to the solder joint structure of the safe body, determine whether the heat affected area between the solder joints is overheated at the frame joint, adjust the welding sequence, obtain the solder joint execution sequence adjustment record, and optimize the welding quality and efficiency.

[0011] As a further solution of the present invention, the solder point energy distribution characteristics include the solder point resistance change rate, the solder point surface temperature gradient, and the solder point heat diffusion. The solder point spacing adjustment results include the solder point layout density, the solder point safety interval, and the heat affected zone range. The solder point temperature attenuation curve includes the heat transfer rate, the temperature peak duration, and the solder point cooling rate. The solder point execution sequence adjustment record includes the solder point heat dissipation timing, the overheating area location, and the heat conduction path optimization.

[0012] As a further solution of the present invention, the steps for obtaining the energy distribution characteristics of the welding spot are specifically as follows:

[0013] S101: Obtain welding current flow direction data during safe cabinet production, collect welding point current values, identify current density changes, identify current distribution characteristics between welding points, and obtain welding point current density distribution data;

[0014] S102: Calculating the voltage drop between solder joints based on the solder joint current density distribution data, retrieving the data set of current value and voltage drop value, analyzing the distribution of solder joint resistance at the differentiated solder joint positions, identifying the solder joint resistance change trend, and obtaining the solder joint resistance change value;

[0015] S103: calling the resistance change value of the solder point, monitoring the temperature of the solder point, calculating the heat accumulation rate, analyzing the thermal conductivity of the metal, identifying the energy diffusion state of the solder point, and obtaining the energy distribution characteristics of the solder point.

[0016] As a further solution of the present invention, the step of obtaining the solder joint spacing adjustment result is specifically as follows:

[0017] S201: Invoking the energy distribution characteristics of the weld points, referring to the weld plate of the safe body, identifying the thickness of the weld plate, surface coating characteristics, and current distribution between weld points, analyzing the heat affected area between weld points, and obtaining the heat affected area of the weld points;

[0018] S202: Based on the heat-affected zone of the weld, calling heat transfer parameters under different plate thicknesses, calculating the heat transfer rate of the weld, analyzing the diffusion of heat in the plates with different thicknesses, evaluating the effect of the plate thickness on the temperature distribution of the weld, and obtaining the heat transfer characteristics of the plate thickness;

[0019] S203: Invoking the plate thickness heat transfer feature, adjusting the solder joint layout according to the material properties, calculating the optimal spacing between the solder joints, adjusting the solder joint arrangement, and obtaining a solder joint spacing adjustment result.

[0020] As a further solution of the present invention, the heat transfer rate of the solder joint is calculated using the formula:

[0021]

[0022] Among them, q represents the heat transfer rate of the solder joint, k represents the thermal conductivity of the plate with different thickness in the heat-affected zone of the solder joint, A represents the heat transfer area of the solder joint, TH represents the high-temperature end temperature of the solder joint area, TC represents the low-temperature end temperature of the solder joint area, L1 represents the heat transfer path length of the solder joint along the thickness direction, and L2 represents the heat transfer path length of the solder joint along the surface direction of the plate.

[0023] As a further solution of the present invention, the steps for obtaining the solder point temperature decay curve are specifically as follows:

[0024] S301: Calling the solder point spacing adjustment result, collecting solder point temperature change data after the spacing adjustment, analyzing the trend of solder point temperature change over time, and obtaining solder point temperature change data;

[0025] S302: Based on the solder point temperature change data, referring to the thermal diffusion rate, thickness and ambient temperature of the metal material, calculating the heat transfer rate of adjacent solder points, analyzing the heat transfer path between the solder points, determining the heat accumulation between the solder points, and obtaining the heat accumulation status of the solder points;

[0026] S303: Analyzing the decay amplitude of the solder point temperature over time using the solder point heat accumulation state, identifying the solder point temperature decay trend, and obtaining a solder point temperature decay curve.

[0027] As a further solution of the present invention, the steps for obtaining the welding point execution sequence adjustment record are specifically as follows:

[0028] S401: Calling the solder point temperature decay curve, calculating the time required for the solder point temperature to drop to a set stable range, calculating the solder point cooling rate, analyzing the temperature change trend of adjacent solder points, analyzing the temperature accumulation under different soldering sequences, and obtaining an optimized solder point ranking sequence;

[0029]

[0030] Among them, R c Represents the solder point cooling rate, T o Represents the solder point temperature at time o, T o-1 represents the solder point temperature at time o-1, M represents the total number of measured temperature time points, t f represents the temperature measurement time, and t0 represents the initial temperature measurement time;

[0031] S402: Utilize the optimized sorting sequence of the weld points, combine it with the welding structure of the safe body, call the distribution of the welding frame and the arrangement of the reinforcement ribs, determine the heat conduction path between the weld points, analyze the temperature change of the heat-affected zone at the frame joint, identify whether overheating occurs, adjust the welding sequence, optimize the weld point execution sequence arrangement, and obtain the weld point execution sequence adjustment record.

[0032] As a further solution of the present invention, the method further includes step S5:

[0033] S5: Based on the welding point execution sequence adjustment record, calling the welding point coordinates, recording the adjusted welding point positions, adjusting the welding path, setting the action sequence of the welding equipment, adjusting the welding current output, correcting the welding power input, and obtaining the adjusted welding path;

[0034] The adjusted welding path includes a welding equipment action sequence, a welding point coordinate adjustment record, a current output correction value, and a welding power correction value.

[0035] As a further solution of the present invention, the step of obtaining the adjusted welding path is specifically as follows:

[0036] S501: Using the weld point execution sequence adjustment record, calling the weld point coordinates, analyzing the positions of the weld points, analyzing the motion path of the welding equipment, analyzing the motion trajectory of the adjusted weld point sequence, setting the motion sequence of the welding equipment, adjusting the welding power input and welding current output, evaluating the matching relationship between power and current, and obtaining the welding path correction result;

[0037] S502: calling the welding path correction result, analyzing the connection sequence of the corrected weld points, adjusting the execution instructions of the welding equipment, matching the welding parameters of the weld points, and obtaining the adjusted welding path.

[0038] On the other hand, the spot welding optimization system based on spacing constraints is used to execute the above-mentioned spot welding optimization method based on spacing constraints, and the system includes:

[0039] The current flow analysis module obtains the welding current data during safe welding, monitors the current flow and distribution between welding points, identifies the resistance changes between welding points, and generates the energy distribution characteristics of welding points;

[0040] The heat-affected zone analysis module uses the energy distribution characteristics of the weld points to analyze the heat-affected zones between the weld points of the welded plates, identifies the heat transfer conditions under different plate thicknesses, adjusts the weld point layout and spacing according to the plate characteristics, and obtains the weld point spacing adjustment results;

[0041] The solder point temperature monitoring module collects the solder point temperature change data after the spacing adjustment based on the solder point spacing adjustment result, records the temperature change, calculates the heat transfer rate between adjacent solder points, and obtains the solder point temperature attenuation curve;

[0042] The path identification module calls the solder point temperature decay curve, analyzes the time required for the solder point temperature to drop to the set range, adjusts the welding sequence according to the welding structure, identifies the heat conduction path between the solder points, and generates a solder point execution sequence adjustment record;

[0043] The welding path adjustment module adjusts the record according to the welding point execution sequence, records the adjusted welding point positions, sets the action sequence and welding current output of the welding equipment, and obtains the adjusted welding path.

[0044] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0045] By acquiring and analyzing welding current flow data, we can gain a detailed understanding of the current distribution between welds and monitor temperature changes at the welds. Continuous monitoring of weld resistance and temperature helps identify and adjust the energy diffusion state between welds, resulting in a more uniform energy distribution. Adjusting the layout and spacing of welds based on the thermal conductivity of the safe metal further improves the stability and consistency of the welding process and reduces material stress and deformation caused by uneven heating. Analyzing temperature changes after welding optimizes the welding sequence and path, reducing the risk of overheating and improving the overall strength and durability of the structure. This precise control and adjustment allows for significant improvements in welding quality and efficiency, particularly for complex components and advanced materials in high-standard production environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic diagram of the workflow of the present invention;

[0047] Figure 2 This is a detailed flow chart of S1 of the present invention;

[0048] Figure 3 This is a detailed flow chart of S2 of the present invention;

[0049] Figure 4 This is a detailed flow chart of S3 of the present invention;

[0050] Figure 5 This is a detailed flow chart of S4 of the present invention;

[0051] Figure 6 This is a detailed flow chart of S5 of the present invention;

[0052] Figure 7 It is a system flow chart of the present invention. DETAILED DESCRIPTION

[0053] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0054] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as an "exemplary" in the present invention should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of the word "exemplary" is intended to present concepts in a concrete manner. Furthermore, in the embodiments of the present invention, "and / or" can mean both or either of the two.

[0055] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0056] See also Figure 1, an embodiment of the present invention provides a spot welding optimization method based on spacing constraints, and the processing flow of the method may include the following steps:

[0057] S1: Obtain welding current flow data during safe cabinet production, analyze the current distribution between welds, monitor the surface temperature of and around welds, analyze the thermal conductivity of metals, identify the energy diffusion state between welds, and obtain the energy distribution characteristics of welds;

[0058] S2: Using the energy distribution characteristics of the weld points, referring to the weld plate of the safe body, the thickness of the weld plate, the surface coating characteristics, and the current distribution between the weld points are called up to analyze the heat-affected zone between the weld points, identify the heat transfer under different plate thicknesses, and adjust the weld point layout and spacing based on the material characteristics to obtain the weld point spacing adjustment results;

[0059] S3: Using the solder joint spacing adjustment results, collect solder joint temperature change data after the spacing adjustment. Referring to the thermal diffusion rate, thickness, and ambient temperature of the metal material, record the solder joint temperature changes, calculate the heat transfer rate between adjacent solder joints, determine the heat accumulation between solder joints, and obtain the solder joint temperature decay curve.

[0060] S4: Analyze the time required for the solder point temperature to drop to the set stable range through the solder point temperature decay curve, analyze the optimal welding sequence of adjacent solder points, refer to the safe body welding structure, call the welding frame distribution and reinforcement arrangement method, identify the solder point heat conduction path, determine whether the heat affected area between the solder points is overheated at the frame splicing, adjust the welding sequence, and obtain the solder point execution sequence adjustment record;

[0061] S5: Based on the welding point execution sequence adjustment record, the welding point coordinates are called, the adjusted welding point positions are recorded, the welding path is adjusted, the action sequence of the welding equipment is set, the welding current output is adjusted, the welding power input is corrected, and the adjusted welding path is obtained;

[0062] The energy distribution characteristics of the solder joints include the solder joint resistance change rate, the solder joint surface temperature gradient, and the solder joint heat diffusion. The solder joint spacing adjustment results include the solder joint layout density, the solder joint safety interval, and the heat affected zone range. The solder joint temperature attenuation curve includes the heat transfer rate, the temperature peak duration, and the solder joint cooling rate. The solder joint execution sequence adjustment record includes the solder joint heat dissipation timing, the overheating area location, and the heat conduction path optimization. The adjusted welding path includes the welding equipment action sequence, the solder joint coordinate adjustment record, the current output correction value, and the welding power correction value.

[0063] See also Figure 2 , the specific steps for obtaining the energy distribution characteristics of the solder joint are:

[0064] S101: Obtain welding current flow direction data during safe cabinet production, collect welding point current values, identify current density changes, identify current distribution characteristics between welding points, and obtain welding point current density distribution data;

[0065] During the welding process, multiple current sensors are placed on the welding path between the positive and negative poles of the welding power supply to ensure the complete measurement data when the current flows through each welding point. At the same time, a high-speed data acquisition device is used to record the current waveform. The data acquisition interval is set to 0.1ms to ensure that the current changes in a short period of time can be accurately captured. The current value of each welding point is collected by averaging multiple sensors to reduce the impact of individual sensor errors on the data. To further analyze the changes in the current density of the welding point, it is necessary to calculate the current density at each welding point. The calculation formula of the current density J is:

[0066]

[0067] Where, I is the instantaneous current at the solder joint, and A is the contact area of the solder joint;

[0068] The contact area of the solder joint can be obtained by measuring the high-resolution microscopic image. If the instantaneous current of a solder joint is set to 150A and the contact area measurement value of the solder joint is 2.5, the current density of the solder joint is calculated as:

[0069]

[0070] After collecting the current density of each welding spot, the current distribution characteristics between each welding spot are analyzed through data comparison. The current gradient between adjacent welding spots is calculated by using the interpolation algorithm to identify the changing trend of current density. To facilitate the observation of the current density distribution, a three-dimensional heat map is used to display the data. The horizontal and vertical axes represent the welding path coordinates, and the color gradient represents the current density. The current density distribution data of the welding spot is obtained.

[0071] S102: Calculating the voltage drop between solder joints based on the solder joint current density distribution data, retrieving the data set of current value and voltage drop value, analyzing the distribution of solder joint resistance at the differentiated solder joint positions, identifying the solder joint resistance change trend, and obtaining the solder joint resistance change value;

[0072] Calculate the voltage drop between solder joints. The voltage drop at each solder joint can be calculated using Ohm's law. The voltage drop U is calculated as follows:

[0073] U = R × I;

[0074] Where R is the resistance of the solder joint, and I is the current passing through the solder joint;

[0075] The solder joint resistance is calculated using the micro-resistance measurement method. After welding, the solder joint resistance is measured using the four-probe method. If the resistance of a solder joint is 0.3mΩ and the current is 150A, the voltage drop calculation result is:

[0076] U = 0.3 × 150 = 45;

[0077] After measuring and calculating the voltage drop values of all solder joints, the data set of current value and voltage drop value is called to analyze the distribution of solder joint resistance at different solder joint locations. Regression analysis is used to establish a relationship model between solder joint resistance, solder joint location, and current density, and identify the trend of solder joint resistance change. The formula for calculating the solder joint resistance change value is as follows:

[0078] ΔR=R max -R min ;

[0079] Among them, R max and R min are the maximum and minimum solder joint resistance values, respectively;

[0080] If the maximum solder joint resistance is set to 0.4mΩ and the minimum solder joint resistance is set to 0.2mΩ, the solder joint resistance change value is calculated as follows:

[0081] ΔR=0.4-0.2=0.2;

[0082] Get the resistance change value of the solder joint.

[0083] S103: Calling the resistance change value of the solder point, monitoring the temperature of the solder point, calculating the heat accumulation rate, analyzing the metal thermal conductivity, identifying the energy diffusion state of the solder point, and obtaining the energy distribution characteristics of the solder point;

[0084] Monitor the temperature of the solder joint. Use a thermocouple or infrared thermometer to measure the surface temperature of the solder joint. After collecting the temperature data, calculate the heat accumulation rate. The calculation formula for the heat accumulation rate Q is: Q = mcΔT;

[0085] Where m is the metal mass of the weld, c is the specific heat capacity of the metal, and ΔT is the temperature change;

[0086] Assuming the solder joint mass is 0.2g, the specific heat capacity is 0.45, and the temperature rises by 10, the heat accumulation rate is calculated as follows:

[0087] Q = 0.2 × 0.45 × 10 = 0.9;

[0088] Analyze the thermal conductivity of the metal, use Fourier's law of heat conduction to calculate the thermal conductivity of the solder joint, identify the energy diffusion state of the solder joint, and the thermal conductivity k of the solder joint is calculated as follows:

[0089]

[0090] Where AD is the heat flux per unit area, k is the thermal conductivity, and dT / dx is the temperature gradient;

[0091] Assuming the temperature gradient of a solder joint is 50K / m and the thermal conductivity is 200, the heat flux density of the solder joint is calculated as follows:

[0092] AD = -200 × 50 = -10000;

[0093] The energy distribution characteristics of the solder joint are obtained by combining the solder joint resistance, temperature and thermal conductivity data.

[0094] See also Figure 3 , the specific steps for obtaining the solder joint spacing adjustment results are:

[0095] S201: Invoking the energy distribution characteristics of the weld points, referring to the weld plate of the safe body, identifying the weld plate thickness, surface coating characteristics, and current distribution between weld points, analyzing the heat affected area between weld points, and obtaining the heat affected area of the weld points;

[0096] It is necessary to identify the properties of the welded plates of the safe body and use an ultrasonic thickness gauge to measure the thickness of the welded plates. The ultrasonic probe emits high-frequency ultrasonic waves on the surface of the welded plates and calculates the actual thickness of the plates by measuring the echo time to ensure data accuracy. Samples are taken and measured at multiple locations around the weld points. After recording the thickness data, an X-ray fluorescence spectrometer (XRF) is used to detect the surface coating of the welded plates. The instrument can excite the surface elements of the plates through high-energy X-rays and analyze the coating material and thickness based on the spectral characteristics. If the safe welded plate coating is an anti-corrosion layer, XRF analysis can determine its main components such as zinc, nickel or chromium, as well as the coating thickness range, such as 0.01mm to 0.05mm. After obtaining the coating thickness, it is necessary to collect the current distribution between the welds. The current value of each solder joint during welding is recorded by a multi-channel current sensor, and stored and analyzed by a data acquisition device. The current data can be normalized in combination with the resistance distribution of the solder joint to obtain the changing trend of the current flow direction between the solder joints, and the heat affected zone of the solder joint is analyzed. The heat diffusion of the solder joint during the welding process is recorded by a high-temperature infrared imager, and the temperature distribution of the solder joint and the surrounding area is measured. Based on the solder joint temperature data, the finite element heat conduction simulation method is used to calculate the heat affected zone of the solder joint. Based on the temperature gradient change trend, the heat affected zone boundary is set. When the temperature around the solder joint drops to near the substrate temperature, its heat affected zone boundary is determined. By comparing the heat diffusion of different solder joints, the heat affected zone of the solder joint is obtained.

[0097] S202: Based on the heat-affected zone of the solder joint, the heat transfer parameters under different plate thicknesses are called to calculate the heat transfer rate of the solder joint, analyze the heat diffusion in the plates with different thicknesses, evaluate the effect of the plate thickness on the temperature distribution of the solder joint, and obtain the heat transfer characteristics of the plate thickness;

[0098] To calculate the heat transfer rate of a solder joint, use the formula:

[0099]

[0100] Where q represents the heat transfer rate of the solder joint, k represents the thermal conductivity of the plate with different thickness in the heat-affected zone of the solder joint, A represents the heat transfer area of the solder joint, TH represents the high-temperature end temperature of the solder joint area, TC represents the low-temperature end temperature of the solder joint area, L1 represents the heat transfer path length of the solder joint along the thickness direction, and L2 represents the heat transfer path length of the solder joint along the plate surface direction.

[0101] Parameter meaning and formula calculation derivation process:

[0102] The heat transfer rate q at the solder joint is determined by the thermal conductivity of the material, the temperature difference in the solder joint area, and the heat transfer path. The values of each parameter are obtained through material property testing, temperature measurement, and geometric measurement.

[0103] The thermal conductivity k of the plate depends on its material composition and thickness. For the duplex steel commonly used in automobile manufacturing, the thermal conductivity is in the range of 40-50. The thermal conductivity of a duplex steel material measured by the heat flow meter method at 300°C is 45.3. This value increases with increasing temperature.

[0104] The effective heat transfer area A of the solder joint is controlled by the welding parameters. The diameter of the solder joint d = 5.2 mm is measured by high-speed photography and the effective heat transfer area is calculated as follows:

[0105]

[0106] Solder point high temperature and low temperature end temperature TH, TC:

[0107] The temperature distribution of the solder joint area was detected by infrared thermal imager. The measured temperature of the solder joint center was TH = 1420K, and the temperature of the area around the solder joint was TC = 680K. The temperature difference was calculated as follows:

[0108] |TH-TC|=|1420-680|=740;

[0109] Heat transfer path lengths L1 and L2:

[0110] The geometric dimensions of the heat-affected zone of the weld were measured using a three-dimensional measuring instrument. The heat transfer path along the thickness direction was L1 = 1.8 mm = 0.0018 m, and the heat transfer path along the plate surface direction was L2 = 3.5 mm = 0.0035 m. The composite heat transfer path was calculated as follows:

[0111]

[0112] Substitute all calculated values into the formula:

[0113]

[0114] Calculate the numerator:

[0115] 45.3×2.124×10 -5 =9.62×10 -4 ;

[0116] 9.62×10 -4 ×740=0.7119;

[0117] Calculated value:

[0118]

[0119] The results show that the heat transfer rate of the solder point is 181.2W, that is, in the solder point area, 181.2J of heat is transferred to the surrounding plate per unit time. The heat transfer rate is affected by the thermal conductivity of the material, the temperature difference of the solder point, and the heat transfer path. This value is used in the subsequent analysis of heat diffusion behavior and the influence of plate thickness on the temperature distribution of the solder point.

[0120] S203: Invoke the plate thickness heat transfer feature, adjust the solder joint layout according to the material properties, calculate the optimal spacing between the solder joints, adjust the solder joint arrangement, and obtain the solder joint spacing adjustment result;

[0121] Adjust the solder joint layout according to the material properties. A reasonable layout of solder joints can reduce the heat accumulation effect and improve the welding quality. It is necessary to calculate the optimal spacing between solder joints. The overlap rate of the heat-affected zone between solder joints is used as an evaluation indicator. If the overlap rate is high, welding defects will result. If the overlap rate is low, the welding strength will be affected. The calculation of the solder joint spacing can be based on the following formula:

[0122] S opt =2R HAZ ;

[0123] Among them, S opt is the optimal solder joint spacing, R HAZ is the radius of the heat affected zone;

[0124] Assume that the thickness of the welded plate of a safe is 3 mm. During the welding process, the radius of the heat-affected zone of the weld at this thickness is measured to be 5 mm. The optimal spacing between welds is calculated as follows:

[0125] S opt =2×5=10;

[0126] Adjust the arrangement of solder joints and use the grid distribution method for uniform layout. For thicker plate areas, appropriately reduce the distance between solder joints to ensure welding strength. For thinner plate areas, appropriately increase the distance between solder joints to reduce the heat accumulation effect. Consider the energy distribution characteristics of solder joints comprehensively and adjust the arrangement of solder joints to ensure that the solder joints are heated evenly. After completing the solder joint layout optimization, ensure that the solder joint temperature is evenly distributed to obtain the solder joint spacing adjustment result.

[0127] See also Figure 4 , the steps for obtaining the solder point temperature decay curve are as follows:

[0128] S301: Calling the solder point spacing adjustment result, collecting the solder point temperature change data after the spacing adjustment, analyzing the trend of the solder point temperature change over time, and obtaining the solder point temperature change data;

[0129] The adjusted solder joint temperature change data needs to be collected. During the welding process, high-precision thermocouple sensors are used to monitor the solder joint temperature in real time. A multi-point arrangement is used, with sensors installed at multiple measurement points around and at the center of each solder joint to obtain more complete temperature distribution data. The data collection interval is set to 10ms to ensure that the temperature change details during the welding process are fully recorded. The temperature data is stored by the data acquisition device and synchronized with the welding timeline to form a curve of the solder joint temperature change over time. During the data processing process, the temperature data is filtered to remove measurement noise. The rising and falling trends of the solder joint temperature are fitted and analyzed. The cubic spline interpolation method is used to construct the solder joint temperature change curve over time, and the temperature change rate at different stages is calculated. In the initial stage of welding, the solder joint temperature rises rapidly, reaches a peak, and then gradually decreases over time. The temperature change curves for different solder joint spacings are different. The temperature rise rate of solder joints with larger spacing is faster, while the temperature of solder joints with smaller spacing decreases more slowly due to the heat accumulation effect. By statistically analyzing the temperature change data of different solder joints, the trend of solder joint temperature change over time can be analyzed and the solder joint temperature change data can be obtained.

[0130] S302: Based on the solder point temperature change data, referring to the thermal diffusion rate, thickness and ambient temperature of the metal material, the heat transfer rate of adjacent solder points is calculated, the heat transfer path between the solder points is analyzed, the heat accumulation between the solder points is determined, and the heat accumulation status of the solder points is obtained;

[0131] The heat transfer rate between adjacent welds is calculated based on the thermal diffusion rate, thickness, and ambient temperature of the metal material. The thermal diffusion rate of the metal material needs to be determined. The thermal diffusion parameters of the safe welding plate are obtained by consulting the material database. For carbon steel, the thermal diffusion rate is approximately 1.2×10 -5 , measure the ambient temperature around the solder joints, and analyze the temperature gradient between the solder joints. Based on the solder joint temperature data, calculate the temperature difference between adjacent solder joints to obtain the driving force of heat transfer. At different solder joint spacings, there are significant differences in the heat transfer rate. For solder joints with smaller spacings, heat can be quickly transferred to adjacent solder joints, while the heat transfer between solder joints with larger spacings is limited, and heat is more likely to diffuse to the surroundings. Analyze the heat transfer path between solder joints, simulate the heat diffusion process between solder joints through simulation, observe the heat flow direction and energy distribution, and judge the heat accumulation between solder joints. If the heat accumulation between adjacent solder joints is high, the solder joint cooling rate will be reduced, affecting the welding quality. Based on the experimental data and simulation analysis, the heat accumulation state of the solder joints is obtained.

[0132] S303: Analyze the temperature decay of the solder point over time using the heat accumulation state of the solder point, identify the temperature decay trend of the solder point, and obtain a temperature decay curve of the solder point;

[0133] Analyze the attenuation of solder point temperature over time to identify the solder point temperature attenuation trend. The solder point temperature attenuation follows the exponential attenuation law, as shown in the following formula:

[0134] T(t)=T0e -kt ;

[0135] Where T(t) is the solder point temperature at a certain moment, T0 is the initial solder point temperature, k is the temperature attenuation coefficient, t is time, and e is a natural constant;

[0136] The initial temperature of a solder joint is set to 1200℃, and the temperature attenuation coefficient is measured to be 0.005s -1 , calculate the temperature of the solder point at different time points:

[0137] When t = 10s,

[0138] T(10)=1200×e -0.005×10 ≈1141.2;

[0139] When t=30s,

[0140] T(30)=1200×e -0.005×30 ≈1027.3;

[0141] When t = 60s,

[0142] T(60)=1200×e -0.005×60 ≈880.8;

[0143] By analyzing the temperature attenuation data of different solder joints, we can observe the attenuation trend under different solder joint spacings and obtain the solder joint temperature attenuation curve.

[0144] See also Figure 5 ,The specific steps for obtaining the solder joint execution sequence adjustment record are:

[0145] S401: Calling the solder point temperature decay curve, calculating the time required for the solder point temperature to drop to the set stable range, calculating the solder point cooling rate, analyzing the temperature change trend of adjacent solder points, analyzing the temperature accumulation under different soldering sequences, and obtaining the solder point optimization sequence;

[0146]

[0147] Among them, R c Represents the solder point cooling rate, T o Represents the solder point temperature at time o, T o-1 represents the solder point temperature at time o-1, M represents the total number of measured temperature time points, t f represents the temperature measurement time, and t0 represents the initial temperature measurement time;

[0148] Detailed explanation of the formula and the process of formula calculation and derivation:

[0149] Parameter acquisition and quantification method:

[0150] Temperature measurement uses an infrared thermometer for data collection, the measurement point interval is set to 0.5 seconds, and the total number of temperature measurement points M = 10;

[0151] Solder point temperature data T o The temperature is obtained through a thermocouple temperature measuring device, and the temperature value of each measuring point is averaged to reduce the error of single measurement;

[0152] Welding cooling time range t f -t0 is measured by a high-precision temperature recorder. The starting time t0 is the time when the solder point temperature reaches the peak value, and the ending time t f The time it takes for the solder point temperature to drop to a stable range is set as t f -t0=5 seconds;

[0153] Parameter value setting:

[0154] The measured solder point temperature data are as follows: T0 = 250°C, T1 = 240°C, T2 = 230°C, T3 = 218°C, T4 = 205°C, T5 = 190°C, T6 = 175°C, T7 = 160°C, T8 = 145°C, T9 = 130°C;

[0155] Formula calculation process:

[0156] Calculate the sum of the absolute values of the temperature changes:

[0157]

[0158] Calculate the cooling rate normalization term:

[0159]

[0160] Substitute the formula to calculate the cooling rate:

[0161]

[0162] The results show that the cooling rate of the solder joint is 5.37 degrees Celsius per second. This value reflects the temperature drop rate of the solder joint during the cooling process and provides a reference for the subsequent optimization of the welding sequence. A high cooling rate leads to increased residual stress inside the solder joint, affecting the quality of the solder joint, while too low a cooling rate affects the welding efficiency.

[0163] S402: Utilizing the optimized sorting sequence of weld points, combined with the weld structure of the safe body, the distribution of the weld frame and the arrangement of the reinforcement ribs are called to determine the heat conduction path between the weld points, analyze the temperature change of the heat-affected zone at the frame joint, identify whether overheating has occurred, adjust the welding sequence, optimize the weld execution sequence, and obtain a weld execution sequence adjustment record;

[0164] Combined with the safe body welding structure, the welding frame distribution and reinforcement arrangement are called up to analyze the heat conduction path between welds. The location of the reinforcement is identified through the welding structure diagram. The reinforcement is used to increase the strength of the safe welded frame. Its material and thickness have a direct impact on the heat transfer between welds. The reinforcement thickness is set to 5mm. The thermal conductivity coefficient is higher than that of ordinary welded plates. The heat diffusion rate of the welds at the reinforcement is faster. Due to the multi-layer welding at the frame splicing, there is a heat accumulation effect. By measuring the solder point temperature at the frame splicing, the temperature change of the heat-affected zone is analyzed. During the welding process, if the measured temperature of a certain solder point exceeds the overheating threshold of 600℃, the material performance will be degraded, and the welding sequence needs to be adjusted to reduce the overheating risk. Based on the optimized sorting sequence, a staggered welding method is adopted to ensure uniform heat distribution and prevent local overheating. Based on the simulation data of the heat-affected zone of the solder point, the solder points with faster temperature changes are prioritized to avoid heat concentration in a certain area. The solder point execution sequence is optimized and a solder point execution sequence adjustment record is generated.

[0165] See also Figure 6 , the specific steps for obtaining the adjusted welding path are:

[0166] S501: Using the weld point execution sequence adjustment record, calling the weld point coordinates, analyzing the weld point position, analyzing the motion path of the welding equipment, analyzing the motion trajectory of the adjusted weld point sequence, setting the motion sequence of the welding equipment, adjusting the welding power input and welding current output, evaluating the matching relationship between power and current, and obtaining the welding path correction result;

[0167] The weld coordinates are called and their positions are analyzed. The actual positions of the welds on the welding frame are scanned using a three-dimensional coordinate measuring machine (CMM) and compared with the design model to ensure that the weld positions accurately match the motion trajectory of the welding equipment. The motion path of the welding equipment is analyzed. Based on the weld coordinate data, the motion trajectory of the welding equipment is modeled using CAD software for welding path planning. The welding robot uses linear or circular interpolation for welding. The path is optimized based on the weld spacing and weld sequence to avoid unnecessary repetitive motion and excessive non-welding movement. The motion trajectory of the adjusted weld sequence is analyzed. The motion sequence of the welding equipment is calculated based on the optimized path, and the motion rate and position accuracy of the welding head are set. The welding power input and welding current output are adjusted. The matching relationship between power and current is affected by the welding material, weld thickness, and electrode contact. The corresponding matching parameters are queried using the welding process database. For 2mm thick mild steel plates, the recommended welding current is 150A and the power setting is 5kW. If the weld spacing is large, the current is appropriately increased to ensure welding quality. By adjusting the welding power and current output, the equipment operating parameters are optimized and the welding path correction results are obtained.

[0168] S502: calling the welding path correction result, analyzing the connection sequence of the corrected weld points, adjusting the execution instructions of the welding equipment, matching the welding parameters of the weld points, and obtaining the adjusted welding path;

[0169] Analyze the connection sequence of the corrected welds, adjust the execution instructions of the welding equipment based on the adjusted welding path, input the optimized welding sequence into the welding robot control system, ensure that the welding head operates according to the corrected path, match the welding parameters of the welds, and set the optimal welding time, welding speed and current waveform according to the weld material and welding method. When using pulse welding, it is necessary to adjust the rising rate of the welding current to reduce the unevenness of the heat input of the weld. Combined with the optimized path, calculate the acceleration and deceleration of the welding head to ensure smooth movement of the welding gun during the welding process and avoid welding defects. Combined with the weld resistance measurement data, adjust the welding current to compensate for the influence of the material surface coating on the current distribution. After completing the welding parameter matching, calibrate the welding path, and use simulation to verify the rationality of the welding trajectory to ensure that all welds are welded in the optimized sequence and obtain the adjusted welding path.

[0170] like Figure 7As shown in FIG, a spot welding optimization system based on spacing constraints includes:

[0171] The current flow analysis module obtains the welding current data during safe welding, monitors the current flow and distribution between welding points, identifies the resistance changes between welding points, and generates the energy distribution characteristics of welding points;

[0172] The heat-affected zone analysis module uses the energy distribution characteristics of weld points to analyze the heat-affected zones between weld points of welded plates, identify the heat transfer conditions under different plate thicknesses, adjust the weld point layout and spacing based on the plate characteristics, and obtain the weld point spacing adjustment results;

[0173] The solder point temperature monitoring module collects the solder point temperature change data after the solder point spacing adjustment, records the temperature change, calculates the heat transfer rate between adjacent solder points, and obtains the solder point temperature attenuation curve;

[0174] The path recognition module calls the solder point temperature decay curve, analyzes the time required for the solder point temperature to drop to the set range, adjusts the welding sequence according to the welding structure, identifies the heat conduction path between the solder points, and generates a record of the solder point execution sequence adjustment;

[0175] The welding path adjustment module adjusts the records according to the welding point execution sequence, records the adjusted welding point positions, sets the action sequence and welding current output of the welding equipment, and obtains the adjusted welding path.

[0176] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A spot welding optimization method based on spacing constraints, characterized in that: The following steps are involved: S1: Obtain welding current flow data during safe cabinet production, analyze the current distribution between welds, monitor the surface temperature of and around welds, analyze the thermal conductivity of metals, identify the energy diffusion state between welds, and obtain the energy distribution characteristics of welds; S2: Using the energy distribution characteristics of the weld points, referring to the welded plates of the safe body, analyzing the heat-affected zones between the weld points, identifying the heat transfer conditions under different plate thicknesses, adjusting the weld point layout and spacing based on the material properties, and obtaining a weld point spacing adjustment result; S3: Using the solder point spacing adjustment result, collecting solder point temperature change data after the spacing adjustment, calculating the heat transfer rate between adjacent solder points with reference to the thermal diffusion rate, thickness and ambient temperature of the metal material, determining the heat accumulation between the solder points, and obtaining a solder point temperature decay curve; S4: Analyze the optimal welding sequence of adjacent solder joints through the solder joint temperature attenuation curve, identify the heat conduction path of the solder joints with reference to the solder joint structure of the safe body, determine whether the heat affected area between the solder joints is overheated at the frame joint, adjust the welding sequence, obtain the solder joint execution sequence adjustment record, and optimize the welding quality and efficiency.

2. The spot welding optimization method based on spacing constraints according to claim 1, characterized in that: The solder point energy distribution characteristics include the solder point resistance change rate, solder point surface temperature gradient, and solder point heat diffusion. The solder point spacing adjustment results include solder point layout density, solder point safety interval, and heat affected zone range. The solder point temperature attenuation curve includes heat transfer rate, temperature peak duration, and solder point cooling rate. The solder point execution sequence adjustment record includes solder point heat dissipation timing, overheating area location, and heat conduction path optimization.

3. The spot welding optimization method based on spacing constraints according to claim 1, characterized in that: The steps for obtaining the energy distribution characteristics of the solder joint are specifically as follows: S101: Obtain welding current flow direction data during safe cabinet production, collect welding point current values, identify current density changes, identify current distribution characteristics between welding points, and obtain welding point current density distribution data; S102: Calculating the voltage drop between solder joints based on the solder joint current density distribution data, retrieving the data set of current value and voltage drop value, analyzing the distribution of solder joint resistance at the differentiated solder joint positions, identifying the solder joint resistance change trend, and obtaining the solder joint resistance change value; S103: calling the resistance change value of the solder point, monitoring the temperature of the solder point, calculating the heat accumulation rate, analyzing the thermal conductivity of the metal, identifying the energy diffusion state of the solder point, and obtaining the energy distribution characteristics of the solder point.

4. The spot welding optimization method based on spacing constraints according to claim 1, characterized in that: The steps for obtaining the solder joint spacing adjustment result are specifically as follows: S201: Invoking the energy distribution characteristics of the weld points, referring to the weld plate of the safe body, identifying the thickness of the weld plate, surface coating characteristics, and current distribution between weld points, analyzing the heat affected area between weld points, and obtaining the heat affected area of the weld points; S202: Based on the heat-affected zone of the weld, calling heat transfer parameters under different plate thicknesses, calculating the heat transfer rate of the weld, analyzing the diffusion of heat in the plates with different thicknesses, evaluating the effect of the plate thickness on the temperature distribution of the weld, and obtaining the heat transfer characteristics of the plate thickness; S203: Invoking the plate thickness heat transfer feature, adjusting the solder joint layout according to the material properties, calculating the optimal spacing between the solder joints, adjusting the solder joint arrangement, and obtaining a solder joint spacing adjustment result.

5. The spot welding optimization method based on spacing constraints according to claim 4 is characterized in that, The heat transfer rate of the solder joint is calculated using the formula: Among them, q represents the heat transfer rate of the solder joint, k represents the thermal conductivity of the plate with different thickness in the heat-affected zone of the solder joint, A represents the heat transfer area of the solder joint, TH represents the high-temperature end temperature of the solder joint area, TC represents the low-temperature end temperature of the solder joint area, L1 represents the heat transfer path length of the solder joint along the thickness direction, and L2 represents the heat transfer path length of the solder joint along the surface direction of the plate.

6. The spot welding optimization method based on spacing constraints according to claim 1 is characterized in that: The steps for obtaining the solder point temperature decay curve are specifically as follows: S301: Calling the solder point spacing adjustment result, collecting solder point temperature change data after the spacing adjustment, analyzing the trend of solder point temperature change over time, and obtaining solder point temperature change data; S302: Based on the solder point temperature change data, referring to the thermal diffusion rate, thickness and ambient temperature of the metal material, calculating the heat transfer rate of adjacent solder points, analyzing the heat transfer path between the solder points, determining the heat accumulation between the solder points, and obtaining the heat accumulation status of the solder points; S303: Analyzing the decay amplitude of the solder point temperature over time using the solder point heat accumulation state, identifying the solder point temperature decay trend, and obtaining a solder point temperature decay curve.

7. The spot welding optimization method based on spacing constraints according to claim 1 is characterized in that: The steps for obtaining the solder joint execution sequence adjustment record are specifically as follows: S401: Calling the solder point temperature decay curve, calculating the time required for the solder point temperature to drop to a set stable range, calculating the solder point cooling rate, analyzing the temperature change trend of adjacent solder points, analyzing the temperature accumulation under different soldering sequences, and obtaining an optimized solder point ranking sequence; Among them, R c Represents the solder point cooling rate, T o Represents the solder point temperature at time o, T o-1 represents the solder point temperature at time o-1, M represents the total number of measured temperature time points, t f represents the temperature measurement time, and t0 represents the initial temperature measurement time; S402: Utilize the optimized sorting sequence of the weld points, combine it with the welding structure of the safe body, call the distribution of the welding frame and the arrangement of the reinforcement ribs, determine the heat conduction path between the weld points, analyze the temperature change of the heat-affected zone at the frame joint, identify whether overheating occurs, adjust the welding sequence, optimize the weld point execution sequence arrangement, and obtain the weld point execution sequence adjustment record.

8. The spot welding optimization method based on spacing constraints according to claim 1 is characterized in that: The method further comprises step S5: S5: Based on the welding point execution sequence adjustment record, calling the welding point coordinates, recording the adjusted welding point positions, adjusting the welding path, setting the action sequence of the welding equipment, adjusting the welding current output, correcting the welding power input, and obtaining the adjusted welding path; The adjusted welding path includes a welding equipment action sequence, a welding point coordinate adjustment record, a current output correction value, and a welding power correction value.

9. The spot welding optimization method based on spacing constraints according to claim 1, characterized in that: The steps for obtaining the adjusted welding path are specifically as follows: S501: Using the weld point execution sequence adjustment record, calling the weld point coordinates, analyzing the positions of the weld points, analyzing the motion path of the welding equipment, analyzing the motion trajectory of the adjusted weld point sequence, setting the motion sequence of the welding equipment, adjusting the welding power input and welding current output, evaluating the matching relationship between power and current, and obtaining the welding path correction result; S502: calling the welding path correction result, analyzing the connection sequence of the corrected weld points, adjusting the execution instructions of the welding equipment, matching the welding parameters of the weld points, and obtaining the adjusted welding path.

10. The spot welding optimization system based on spacing constraints is characterized by: According to any one of claims 1 to 9, the spot welding optimization method based on spacing constraints comprises: The current flow analysis module obtains the welding current data during safe welding, monitors the current flow and distribution between welding points, identifies the resistance changes between welding points, and generates the energy distribution characteristics of welding points; The heat-affected zone analysis module uses the energy distribution characteristics of the weld points to analyze the heat-affected zones between the weld points of the welded plates, identifies the heat transfer conditions under different plate thicknesses, adjusts the weld point layout and spacing according to the plate characteristics, and obtains the weld point spacing adjustment results; The solder point temperature monitoring module collects the solder point temperature change data after the spacing adjustment based on the solder point spacing adjustment result, records the temperature change, calculates the heat transfer rate between adjacent solder points, and obtains the solder point temperature attenuation curve; The path identification module calls the solder point temperature decay curve, analyzes the time required for the solder point temperature to drop to the set range, adjusts the welding sequence according to the welding structure, identifies the heat conduction path between the solder points, and generates a solder point execution sequence adjustment record; The welding path adjustment module adjusts the record according to the welding point execution sequence, records the adjusted welding point positions, sets the action sequence and welding current output of the welding equipment, and obtains the adjusted welding path.

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