Evaluation method, system and equipment for metal brazing lap joint quality and storage medium

Abstract

The invention discloses a metal brazing lap joint quality evaluation method, system and device and a storage medium, and the method comprises the steps: constructing a geometric model, which comprises the steps: obtaining the three-dimensional size of a to-be-lapped metal device, and building a three-dimensional equivalent model; material parameters of two kinds of to-be-lapped metal and brazing solder in the to-be-lapped metal equipment are obtained, and the brazing process is equivalent to a cubic structure with the same material attribute as the brazing solder; in the calculation simulation process, if the lap resistance obtained according to the radio frequency band is obviously higher than the corresponding reference lap resistance in the total requirements of equipment development, adjusting the structure of the to-be-lapped metal equipment; and according to the electrical size of the geometric model, selecting a corresponding electromagnetic algorithm, and further calculating the lapping impedance to reflect the lapping quality. According to the method, by simulating the lap joint quality condition of any two metal plates in the brazing process, the lap joint effectiveness between the two metal plates can be pre-judged in advance, then the process of lap joint between the metal plates through brazing is optimized, and the electromagnetic compatibility problem of equipment caused by poor contact between shells of the equipment is solved.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic safety, and in particular to a method, system, terminal equipment, and computer-readable storage medium for evaluating the quality of metal brazing lap joints. Background Technology

[0002] With the improvement of computing power, the number of operations per unit time of the central processing unit increases exponentially; the increase in computing speed leads to the decrease in the rise time of digital signals, which in turn leads to the decreasing timing margin of digital systems; this causes problems with the integrity of digital signals, and the reflection and crosstalk of high-speed signals on transmission lines, which in turn causes electromagnetic compatibility problems at the equipment board level. In order to reduce the problems caused by electromagnetic compatibility of equipment, four methods are commonly used: shielding, filtering, grounding, and isolation. Electromagnetic compatibility failures caused by poor shielding effectiveness of equipment housings often occur. The main reasons affecting the shielding effectiveness of equipment are as follows: (i) windows and openings in the equipment housing; (ii) material properties of the equipment housing; (iii) grounding properties of the equipment housing; (iv) gaps at the connection of the equipment housing. The first three points are more related to the design stage, while gaps at the connection of the housing may be caused by the limitations of subsequent processing technology. Later overlapping can improve this process. According to electromagnetic theory analysis, an ideal closed metal housing can shield intentional or unintentional radio signals.

[0003] Consumer products, due to cost considerations, typically use plastic or other composite materials for their casings. However, plastics and common composite materials lack electromagnetic wave resistance; in fields with high reliability requirements, such as aerospace and military, metal casings become the inevitable choice. Considering the difficulty of molding a casing in one piece, casings often require multiple machine tool processing steps. Processing errors between the casing surfaces can create unnecessary gaps. To improve the shielding effectiveness, casings need good overlap properties to facilitate the formation of an equipotential body upon power-up, thereby improving the shielding efficiency. Overlapping methods between casings are divided into permanent overlaps and semi-permanent overlaps. Permanent overlaps mainly refer to the fixed connection of any two metal materials through processes such as riveting, welding, brazing, and pressing. Permanent overlaps maintain stable low-impedance electrical performance throughout the device's lifespan. Semi-permanent overlaps utilize bolts, screws, clamps, and other auxiliary devices to maintain the connection between two metal objects. This facilitates device modification, maintenance, and component replacement, is beneficial for measurement work, and can reduce system costs. In practical operation, to verify the quality of the overlap between metals, it is necessary to determine the rationality of the overlap resistance. Patent CN202210931606.1, used for impedance analysis of electrical connections in composite materials, primarily employs bolts for multi-port fixing and connection. This structure is often seen in aircraft fuselage fixing and represents a specific case analysis, thus its application has some limitations. Patent CN202011302581.6, used for evaluating the resistance of equipment grounding conductors, still uses bolt connections. Over time, long-term corrosion of the bolts may lead to gaps between the connecting plates, causing grounding resistance drift or loose connections. Summary of the Invention

[0004] To address the electromagnetic compatibility (EMC) failures caused by poor brazing lap joint quality between two metal materials in equipment housings, this invention provides a method, system, terminal device, and computer-readable storage medium for evaluating the quality of metal brazing lap joints. By simulating the lap joint quality of any two metal plates during the brazing process, the effectiveness of the lap joint between the two metals can be predicted in advance, thereby optimizing the brazing process for lap joints between metal plates and reducing EMC problems caused by poor contact between the equipment housings.

[0005] The first objective of this invention is to provide a method for evaluating the quality of metal brazing lap joints.

[0006] The second objective of this invention is to provide a system for evaluating the quality of metal brazing lap joints.

[0007] The third objective of this invention is to provide a terminal device.

[0008] A fourth objective of this invention is to provide a computer-readable storage medium.

[0009] The first objective of this invention can be achieved by adopting the following technical solution: A method for evaluating the quality of metal brazing lap joints, the method comprising: Constructing a geometric model includes obtaining the three-dimensional dimensions of the metal equipment to be joined and establishing a three-dimensional equivalent model; as well as obtaining the material parameters of the two metals to be joined and the brazing filler metal in the metal equipment to be joined, and equating the brazing process to a cubic structure with the same material properties as the brazing filler metal. If the lap resistance obtained from the radio frequency band is significantly higher than the corresponding reference lap resistance in the overall requirements for equipment development during the calculation and simulation process, the structure of the metal equipment to be lapped will be adjusted. Based on the electrical dimensions of the geometric model, the corresponding electromagnetic algorithm is selected to calculate the lap impedance, which reflects the lap quality.

[0010] Furthermore, when establishing the three-dimensional equivalent model, brazing solder is used to connect the two metals to be joined; wherein the two metals to be joined are homogeneous or heterogeneous.

[0011] Furthermore, when establishing the three-dimensional equivalent model, the spatial geometric model of the metal equipment to be joined is reproduced proportionally.

[0012] Furthermore, the material parameters include at least electrical conductivity.

[0013] Further adjustments include increasing the overlap area between the two metals to be joined.

[0014] Furthermore, if the electrical dimension is greater than 100, the finite-difference time-domain algorithm is selected; if the electrical dimension is greater than 10 and less than 100, the method of moments is selected; if the electrical dimension is less than 10, the finite element algorithm is selected.

[0015] Furthermore, the electrical dimensions are calculated through the following process: Let the frequency of the electromagnetic wave passing through the overlapping surface be... The corresponding wavelength Where c is the speed of light; Let the length, width, and height of the metal equipment to be joined be Length, Width, and Height, respectively. The electrical dimension of the geometric model is k = max(Length, Width, Height) / ; where max() means taking the maximum value among the parameters.

[0016] The second objective of this invention can be achieved by adopting the following technical solution: A system for evaluating the quality of metal brazing lap joints, the system comprising: The model building module is used to build a geometric model, including obtaining the three-dimensional dimensions of the metal equipment to be joined and establishing a three-dimensional equivalent model; and obtaining the material parameters of the two metals to be joined and the brazing filler metal in the metal equipment to be joined, and equating the brazing process to a cubic structure with the same material properties as the brazing filler metal. The adjustment module is used to adjust the structure of the metal equipment to be connected if the lap resistance obtained from the radio frequency band is significantly higher than the corresponding reference lap resistance in the overall requirements of equipment development during the calculation and simulation process. The evaluation module is used to select the corresponding electromagnetic algorithm based on the electrical dimensions of the geometric model, and then calculate the lap impedance to reflect the lap quality.

[0017] The third objective of this invention can be achieved by adopting the following technical solution: A terminal device includes a processor and a memory for storing a processor-executable program, wherein when the processor executes the program stored in the memory, it implements the above-described method for evaluating the quality of metal brazing lap joints.

[0018] The fourth objective of this invention can be achieved by adopting the following technical solution: A computer-readable storage medium storing a program that, when executed by a processor, implements the above-described method for evaluating the quality of metal brazing lap joints.

[0019] The present invention has the following advantages over the prior art: Compared to existing RF impedance testing methods that require specially designed test fixtures for each test, increasing testing costs and limiting the measurement frequency band by the instrument, this invention can greatly improve efficiency, reduce trial and error costs, promote technological upgrades, and significantly enhance the predictability and feasibility of the design. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0021] Figure 1 This is a flowchart of the method for evaluating the quality of metal brazing lap joints according to Embodiment 1 of the present invention; Figure 2 This is the three-dimensional equivalent model of Embodiment 1 of the present invention; Figure 3This is a schematic diagram of the mesh generation of the three-dimensional equivalent model of Embodiment 1 of the present invention; Figure 4 This is a structural block diagram of the metal brazing lap joint quality evaluation system according to Embodiment 2 of the present invention; Figure 5 This is a structural block diagram of the terminal device according to Embodiment 3 of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be understood that the specific embodiments described are merely used to explain this application and are not intended to limit this application.

[0023] Example 1: like Figure 1 As shown, this embodiment provides a method for evaluating the quality of metal brazing lap joints, including the following steps: S101. Obtain the three-dimensional dimensions of the overlapping metal equipment and establish a three-dimensional equivalent model.

[0024] When using software to assess the quality of overlaps, it is necessary to recreate the spatial geometric model of the equipment at a proportional scale. The main reasons for this are as follows: Spatial complexity: The behavior of electromagnetic fields is often influenced by geometry, material properties, and the surrounding environment. These complexities can be captured more accurately in three-dimensional space. Non-uniformity: Real-world electromagnetic problems involve non-uniform electromagnetic field distributions and complex boundary conditions. Three-dimensional simulations can better account for these non-uniformities and accurately simulate the behavior of electromagnetic fields in different regions. Electromagnetic interaction effect: In a three-dimensional structure, electromagnetic fields may interact with the structural components; Precision and accuracy. For many applications, such as antenna design and electromagnetic compatibility analysis, three-dimensional structural models can improve the precision and accuracy of simulations, making them more consistent with reality.

[0025] Typically, the geometric model of equipment is designed by structural engineers using CAD software, and its three-dimensional dimensions can be directly obtained from the software. However, in some cases, direct measurement methods are required to construct the corresponding geometric model. For example, when the grounding busbar in a power distribution cabinet is connected to the earth, the overlap between the grounding busbar and the ground wire needs to be constructed based on the actual situation. This embodiment uses an equivalent transformation to evaluate the quality of overlaps between metal parts of equipment: brazing is used to directly connect two metal materials, therefore the connection must involve welding between two homogeneous or dissimilar metals, and the solder is used as the connecting component, such as... Figure 2 As shown. A represents the side that needs to be overlapped, and metal B represents the side that is overlapped. Any two metals A and B are connected using brazing filler metal.

[0026] S102. Obtain the parameters of the metallic material.

[0027] Electromagnetic software requires specific material parameters of the geometric model when performing calculations, also for the following reasons: The reasons why electromagnetic simulation requires material parameters are as follows: The electromagnetic properties of materials, such as dielectric constant, conductivity, and magnetic permeability, have a significant impact on processes such as the propagation, reflection, and absorption of electromagnetic fields. Material inhomogeneity: The material parameters in many structures are inhomogeneous and may vary with location and orientation. For example, composite materials or materials with gradient structures have different electromagnetic properties in different regions; Interaction effect: The electromagnetic properties of a material may interact with an electromagnetic field, affecting the distribution and behavior of the electromagnetic field.

[0028] according to Figure 2 According to the brazing equivalent model, the metal materials mainly include A, B and the lap strip, and the key parameter of the material is the electrical conductivity.

[0029] S103, Equivalent Brazing Process.

[0030] During brazing, a laser beam is used to melt and evenly distribute the filler metal between two metal plates. After the temperature drops, the two metals are joined. Because the filler metal melts and penetrates between the two lapped metals, its cross-section forms a cubic structure. Therefore, the brazing process can be considered equivalent to a cubic structure with properties consistent with the filler metal material.

[0031] The resistance of a material can be calculated using the following formula: ,in Let L be the resistivity of the brazing material, L be the length of the brazing material, and S be the cross-sectional area of ​​the brazing material. Since different brazing materials have different resistivities, the values ​​need to be determined based on the material properties of the actual lap joints. Furthermore, due to the advantage of laser directionality during laser brazing, the brazed surface is uniformly smooth, and the lap length and lap area can also be obtained using measuring tools such as vernier calipers.

[0032] S104. Based on the 3D model, update the initial parameters and boundary conditions of the material.

[0033] Through the equivalent process of brazing described above and the acquisition of relevant information about the metal materials, the entire geometric model is finally constructed. Since the quality of the bridging in the radio frequency band is frequently evaluated during testing, the spectral range of the radio frequency band needs to be considered when calculating the parameters. Typically, the DC bridging resistance corresponds to the resistance at 0Hz, and a resistance value below 0.1Ω indicates good bridging quality. The radio frequency band usually refers to electromagnetic waves with frequencies between 3kHz and 300GHz. Taking low-frequency (30kHz~300kHz) electromagnetic waves as an example, the bridging impedance within the low-frequency (30kHz~300kHz) band only needs to meet the reference value of the overall equipment development requirements. If the values ​​obtained during the calculation and simulation process are significantly higher than the reference bridging resistance in the overall equipment development requirements, adjustments to the equipment structure should be made, such as increasing the bridging area.

[0034] S105. Construct a complete evaluation model for the quality of the overlap and obtain the results.

[0035] After completing steps S101~S104, the mesh generation of the geometric model is completed, as follows: Figure 3 As shown. Before running the simulation calculation, a specific algorithm for computational electromagnetics needs to be selected based on the electrical dimensions of the computational model.

[0036] The electrical dimensions of the model can be calculated using the following formula: (1) Assume the frequency of the electromagnetic wave passing through the overlapping surface is The corresponding wavelength is Where c(3*10) 8 m / s is the speed of light; (2) Assume that the maximum value of the length, width and height of the metal equipment to be joined is max(Length, Width, Height), and max() is used to get the maximum value of the parameter in parentheses; (3) The electrical dimensions are obtained by comparing the wavelength of the electromagnetic wave with the maximum geometric dimensions of the objects to be joined. The specific calculation is as follows: When k > 100, the object is electrically large; when 100 > k > 10, the object is electrically medium; when k < 10, the object is electrically small.

[0037] For electrically large dimensions, the finite-difference time-domain algorithm (such as the software EMA3D) can be used; for electrically medium dimensions, the method of moments (such as the software ADS) can be used; and for electrically small dimensions, the finite element algorithm (such as the software HFSS) can be used.

[0038] To reduce the time required for electromagnetic calculations, the simulation project should be run on a server with at least 8 cores and ultimately obtain the overlap quality between the two metal plates.

[0039] The quality of the overlap is reflected by the overlap impedance, which can be obtained by the ratio of RF voltage to RF current. ,in and Add a unit radio frequency excitation current to the model ( When ) the corresponding radio frequency voltage across metal AB ( ).

[0040] This embodiment can also provide a model for optimizing the brazing process by analyzing the lap resistance values ​​formed by different brazing angles, temperatures and solder compositions, and by using corresponding machine learning algorithms, thereby improving the reliability of lap metal equipment.

[0041] Specifically, brazing filler metals can be classified according to their welding temperature into soft filler metals (melting point below 450℃), hard filler metals (melting point above 450℃), and high-temperature filler metals (melting point above 950℃). Different filler metals contain different material compositions. By adjusting the proportions of the raw materials, filler metals with different material properties can be obtained. Furthermore, the optimal brazing filler metal can be obtained by automatically adjusting the proportions and analyzing the results using a computer.

[0042] Those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware, and the corresponding program can be stored in a computer-readable storage medium.

[0043] It should be noted that although the method operations of the above embodiments are described in a specific order in the accompanying drawings, this does not require or imply that these operations must be performed in that specific order, or that all the operations shown must be performed to achieve the desired result. On the contrary, the order of execution of the described steps may be changed. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0044] Example 2: like Figure 4As shown, this embodiment provides a system for evaluating the quality of metal brazing lap joints. The system includes a model building module 401, an adjustment module 402, and an evaluation module 403, wherein: The model building module 401 is used to build a geometric model, including obtaining the three-dimensional dimensions of the metal equipment to be joined and establishing a three-dimensional equivalent model; and obtaining the material parameters of the two metals to be joined and the brazing filler metal in the metal equipment to be joined, and equating the brazing process to a cubic structure with the same material properties as the brazing filler metal. The adjustment module 402 is used to adjust the structure of the metal equipment to be connected if the lap resistance obtained according to the radio frequency band is significantly higher than the corresponding reference lap resistance in the overall requirements of equipment development during the calculation and simulation process. Evaluation module 403 is used to select the corresponding electromagnetic algorithm based on the electrical dimensions of the geometric model, and then calculate the lap impedance to reflect the lap quality.

[0045] The specific implementation of each module in this embodiment can be found in Embodiment 1 above, and will not be repeated here. It should be noted that the system provided in this embodiment is only illustrated by the division of the above functional modules. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure can be divided into different functional modules to complete all or part of the functions described above.

[0046] Example 3: This embodiment provides a terminal device, which can be a computer, such as... Figure 5 As shown, the system bus 501 connects a processor 502, a memory, an input device 503, a display 504, and a network interface 505. The processor provides computing and control capabilities. The memory includes a non-volatile storage medium 506 and internal memory 507. The non-volatile storage medium 506 stores the operating system, computer programs, and a database. The internal memory 507 provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. When the processor 502 executes the computer programs stored in the memory, it implements the metal brazing lap joint quality evaluation method of Embodiment 1 above, as follows: Constructing a geometric model includes obtaining the three-dimensional dimensions of the metal equipment to be joined and establishing a three-dimensional equivalent model; as well as obtaining the material parameters of the two metals to be joined and the brazing filler metal in the metal equipment to be joined, and equating the brazing process to a cubic structure with the same material properties as the brazing filler metal. If the lap resistance obtained from the radio frequency band is significantly higher than the corresponding reference lap resistance in the overall requirements for equipment development during the calculation and simulation process, the structure of the metal equipment to be lapped will be adjusted. Based on the electrical dimensions of the geometric model, the corresponding electromagnetic algorithm is selected to calculate the lap impedance, which reflects the lap quality.

[0047] Example 4: This embodiment provides a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the method for evaluating the quality of metal brazing lap joints in Embodiment 1 above, as follows: Constructing a geometric model includes obtaining the three-dimensional dimensions of the metal equipment to be joined and establishing a three-dimensional equivalent model; as well as obtaining the material parameters of the two metals to be joined and the brazing filler metal in the metal equipment to be joined, and equating the brazing process to a cubic structure with the same material properties as the brazing filler metal. If the lap resistance obtained from the radio frequency band is significantly higher than the corresponding reference lap resistance in the overall requirements for equipment development during the calculation and simulation process, the structure of the metal equipment to be lapped will be adjusted. Based on the electrical dimensions of the geometric model, the corresponding electromagnetic algorithm is selected to calculate the lap impedance, which reflects the lap quality.

[0048] It should be noted that the computer-readable storage medium in this embodiment can be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof.

[0049] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope disclosed in the present invention, based on the technical solution and inventive concept of the present invention, shall fall within the scope of protection of the present invention.

Claims

1. A method for evaluating the quality of metal brazing lap joints, characterized in that, The method includes: Constructing a geometric model includes obtaining the three-dimensional dimensions of the metal equipment to be joined and establishing a three-dimensional equivalent model; as well as obtaining the material parameters of the two metals to be joined and the brazing filler metal in the metal equipment to be joined, and equating the brazing process to a cubic structure with the same material properties as the brazing filler metal. If the lap resistance obtained from the radio frequency band is significantly higher than the corresponding reference lap resistance in the overall requirements for equipment development during the calculation and simulation process, the structure of the metal equipment to be lapped will be adjusted. Based on the electrical dimensions of the geometric model, the corresponding electromagnetic algorithm is selected to calculate the lap impedance, which reflects the lap quality.

2. The evaluation method according to claim 1, characterized in that, When establishing a three-dimensional equivalent model, two metals to be joined are connected using brazing solder; wherein the two metals to be joined are homogeneous or dissimilar metals.

3. The evaluation method according to any one of claims 1 and 2, characterized in that, When creating a three-dimensional equivalent model, the spatial geometric model of the metal equipment to be joined is reproduced proportionally.

4. The evaluation method according to any one of claims 1 and 2, characterized in that, The material parameters include at least electrical conductivity.

5. The evaluation method according to any one of claims 1 and 2, characterized in that, The adjustment includes increasing the overlap area between the two metals to be joined.

6. The evaluation method according to any one of claims 1 and 2, characterized in that, If the electrical dimension is greater than 100, the finite-difference time-domain algorithm is selected; if the electrical dimension is greater than 10 and less than 100, the method of moments is selected; if the electrical dimension is less than 10, the finite element algorithm is selected.

7. The evaluation method according to claim 6, characterized in that, Electrical dimensions are calculated using the following process: Let the frequency of the electromagnetic wave passing through the overlapping surface be... The corresponding wavelength Where c is the speed of light; Let the length, width, and height of the metal equipment to be joined be Length, Width, and Height, respectively. The electrical dimension of the geometric model is k = max(Length, Width, Height) / ; where max() means taking the maximum value among the parameters.

8. A system for evaluating the quality of metal brazing lap joints, characterized in that, The system includes: The model building module is used to build a geometric model, including obtaining the three-dimensional dimensions of the metal equipment to be joined and establishing a three-dimensional equivalent model; and obtaining the material parameters of the two metals to be joined and the brazing filler metal in the metal equipment to be joined, and equating the brazing process to a cubic structure with the same material properties as the brazing filler metal. The adjustment module is used to adjust the structure of the metal equipment to be connected if the lap resistance obtained from the radio frequency band is significantly higher than the corresponding reference lap resistance in the overall requirements of equipment development during the calculation and simulation process. The evaluation module is used to select the corresponding electromagnetic algorithm based on the electrical dimensions of the geometric model, and then calculate the lap impedance to reflect the lap quality.

9. A terminal device, comprising a processor and a memory for storing a processor-executable program, characterized in that, When the processor executes the program stored in the memory, it implements the evaluation method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the evaluation method according to any one of claims 1 to 7.

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