An ultra-thin micro-size pole ring laser welding penetration characterization and quality improvement method

Abstract

The application belongs to the technical field of 3C new energy product manufacturing, and discloses a method for characterizing the penetration depth of annular laser welding of ultra-thin micro-size pole rings and improving the quality. An annular laser welding system and a CCD coaxial positioning system are used to build a precision welding platform, with 3C new energy product commonly used 3-series aluminum alloy ultra-thin micro-size pole rings and covers as the welding base material. The laser focal point positioning mode and the core welding process parameter interval suitable for the pole rings are determined, and a special penetration depth evaluation process and judgment standard are established. The application optimizes the annular laser welding process parameters, standardizes the welding operation process, and matches the special penetration depth evaluation process system, to solve the technical bottleneck of the existing laser welding technology applied to the processing of the pole rings. The application solves the industry technical problems of poor uniformity of the penetration depth, narrow process window, high weld defect rate, low welding precision, and insufficient precision of the penetration depth evaluation and poor working condition adaptability caused by the small structure size and thin wall thickness of the ultra-thin micro-size pole rings.

Description

Technical Field

[0001] This invention relates to the field of new energy product manufacturing technology in the 3C industry, specifically to a method for characterizing the penetration depth and improving the quality of ultrathin micro-sized electrode ring laser welding. Background Technology

[0002] With the rapid development of new energy technologies in the 3C industry, miniaturization and thinness have become the core development trends of 3C new energy products. The corresponding electrode posts are also developing towards ultra-thin and small size. Among them, the 3-series aluminum alloy ultra-thin small-size electrode posts with a diameter of 2mm and a thickness of 0.2mm are widely used in small new energy batteries, portable new energy devices and other 3C products. They are the core conductive components of 3C new energy products, and the welding quality between them and the cover plate directly determines the performance, service life and safety of 3C new energy products.

[0003] Currently, laser welding is the mainstream solution for welding ultra-thin, small-sized electrodes in the 3C industry. However, due to the small size (only 2mm in diameter) and thin thickness (only 0.2mm) of these electrodes, traditional laser welding process parameters have not been optimized for their size characteristics, resulting in several technical challenges: First, the process parameters are not standardized and have poor adaptability, leading to violent molten pool reactions, poor keyhole stability, and weld defects such as collapse, spatter, and porosity, which cannot meet the precision appearance and performance requirements of 3C products. Second, the penetration uniformity is poor. The welding area of ​​small-sized electrodes is narrow, making energy control difficult and prone to local insufficient penetration or over-melting, affecting conductivity. Third, the process window is narrow and the fault tolerance is weak. In the mass production process of the 3C industry, even small fluctuations in parameters can lead to welding defects, making it unsuitable for mass production needs. Fourth, the positioning accuracy is insufficient. Coaxial positioning of small-sized electrodes is difficult, and positioning deviations can easily lead to weld offset, directly causing product scrap.

[0004] In existing technologies, there is no set of ring laser welding process parameters and operating methods specifically adapted to the ultra-thin, small-sized electrode posts of the 3C industry's new energy sector. Traditional welding methods are all designed for electrode posts of conventional sizes, failing to address the welding challenges unique to the 3C industry and hindering the miniaturization and precision development of new energy products in the 3C sector. Therefore, identifying suitable core welding process parameters and standardized operating methods based on the dimensional characteristics of ultra-thin, small-sized electrode posts in the 3C industry's new energy sector is crucial to solving the welding challenges of new energy electrode posts in the 3C industry. Summary of the Invention

[0005] To overcome the shortcomings and deficiencies of existing technologies, the present invention aims to provide a method for characterizing the penetration depth and improving the quality of annular laser welding of ultrathin micro-sized electrode posts. The core of this invention is to combine the dimensional characteristics (2mm diameter, 0.2mm thickness) of ultrathin small-sized electrode posts in the 3C industry's new energy sector, clarify the range of welding process parameters suitable for this type of electrode post, optimize the optimal parameter combination, and standardize the operation methods for each step to ensure welding accuracy, stability, and compatibility.

[0006] The objective of this invention is achieved through the following technical solution: a method for characterizing the penetration depth and improving the quality of ultrathin micro-sized annular laser welding, comprising the following steps: (1) Setting up a welding platform: The welding platform is a precision platform specifically adapted to the welding of ultra-thin small-sized pole pieces in the new energy industry of 3C. It consists of a laser welding control system and a CCD coaxial positioning system. The core components and parameter requirements are as follows: The laser welding control system includes a 500 / 500W ring laser, an F100 collimating lens, an F254 field lens, a Raylase fourth-generation 20 galvanometer, and a laser control card. The ring laser is used to provide a ring-shaped distribution of laser energy to meet the ring welding requirements of small-sized pole pieces and avoid over-melting caused by energy concentration. The collimating lens and field lens adjust the laser beam parameters to ensure that the laser energy is accurately focused on the small-sized welding area. The galvanometer controls the laser welding trajectory to improve the trajectory accuracy and meet the welding requirements of small-sized pole pieces. The laser control card receives position information and controls the welding program to ensure accurate parameter control. The CCD coaxial positioning system uses a high-definition coaxial camera to capture the relative position of the ultra-thin, small-sized pole and cover plate, achieving high-precision coaxial positioning of the two. The positioning accuracy is controlled at the micron level, avoiding weld offset caused by positioning deviation, ensuring accurate welding position, and meeting the precision requirements of 3C products. (2) Workpiece preparation: The workpiece to be welded is a 3-series aluminum alloy ultra-thin small-sized pole and cover plate for new energy products in the 3C industry. Its chemical composition (mass fraction) is: Mn 1.5%, Cu 0.2%, Fe 0.7%, Si 0.6%, Zn 0.1%, and the rest is Al. This composition is suitable for the conductivity and corrosion resistance requirements of 3C new energy products. The pole specifications are 2mm in diameter, 1.2mm in height, and 0.2mm in thickness. The cover specifications are 2mm in diameter and 0.3mm in thickness. The cover size is precisely matched with the pole to meet the small-size welding requirements. The pole and cover are connected and fixed by an adapter plate and sealant. The key to the operation is to ensure that the two fit tightly without gaps. Since the pole is small and thin, gaps can easily lead to welding defects (such as incomplete penetration and porosity). Therefore, the fitting accuracy directly determines the welding quality and lays the foundation for the precise control of subsequent welding parameters. (3) Laser focus positioning method: The weld width minimization criterion is adopted. In the Z-axis height range of 32.9mm~35.7mm, a straight line with a length of 20mm is etched by a ring laser in a step of 0.2mm. The width of each straight line is measured to determine the laser focus position as 34.3mm on the Z-axis. Subsequent welding is carried out at this focus position to ensure that the welding energy is accurately applied to the welding area of ​​the small-sized pole piece. To address the welding precision requirements of ultra-thin, small-sized electrodes in the 3C industry's new energy sector, a weld width minimization criterion is adopted to locate the laser focus. This criterion is based on the Gaussian beam propagation characteristics, and the relationship is as follows: Where W(z) is the beam diameter at defocus Z, W0 is the beam waist diameter, and λ is the laser wavelength. W(z) is minimum when z=0, which is the focal point. The specific operation method is as follows: Place a black metal business card on the experimental platform. Using the same laser process parameters as actual welding, within the Z-axis height range of 32.9mm~35.7mm, etch a 20mm long straight line in 0.2mm increments. Conduct 15 sets of experiments. By measuring the width of each straight line, the minimum etch width is determined at Z-axis 34.3mm, which is the laser focal point. All subsequent welding tests are performed at this focal point to avoid defects such as uneven weld seam and width fluctuations caused by focal deviation. This ensures that the laser energy is precisely applied to the welding area of ​​the small-sized electrode, meeting the precision welding requirements of 3C products. (4) Ring laser welding process and parameter control: Start the CCD coaxial positioning system to complete the high-precision coaxial positioning of the ultra-thin small-sized pole and the cover plate, turn on 99.99% nitrogen protection to avoid oxidation during welding of ultra-thin poles; adjust the welding parameters of the ring laser and start the welding program. The welding parameters are the precise parameters adapted to ultra-thin small-sized poles: the spot delay is set to 3000~10000μs, the spot spacing is set to 0.025~0.040mm, the spot welding time is set to 0.2~0.5ms, and the center power ratio is 24%~36%; the welding trajectory adopts circular line welding, circular oscillating welding, spiral line welding or circular transformation into spot welding trajectory, preferably circular transformation into spot welding trajectory, to adapt to the ring welding requirements of small-sized poles and improve welding accuracy; The specific steps of ring laser welding are as follows: ① Preparation before welding: Start the CCD coaxial positioning system to capture the position information of the ultra-thin small-sized electrode and the cover plate, adjust the position of the workpiece to be coaxial with the two, and achieve a positioning accuracy of micron level to ensure accurate welding position and avoid weld seam offset when welding small-sized electrodes; turn on 99.99% nitrogen protection. Since the new energy electrode in the 3C industry is thin, it is easy to oxidize during welding. Nitrogen protection can effectively prevent aluminum alloy oxidation and avoid weld seam defects (such as porosity and slag inclusion) caused by oxidation, ensuring the stability of welding quality and adapting to the appearance and performance requirements of 3C products; ② Welding Parameter Range Setting: Considering the size characteristics of ultra-thin small-sized electrodes (2mm diameter, 0.2mm thickness) in the 3C industry's new energy sector, the following parameter range for ring laser welding is determined: spot delay 3000~10000μs, spot spacing 0.025~0.040mm, spot welding time 0.2~0.5ms, and center power ratio 24%~36%. The principle for parameter adjustment is as follows: spot delay affects the weld overlap width, adapting to the ring weld requirements of small-sized electrodes to avoid excessively wide or narrow overlaps; spot spacing affects the uniformity of penetration depth, as the welding area of ​​small-sized electrodes is narrow, the spot spacing needs to be precisely controlled to ensure effective fusion of the molten pool without over-melting; spot welding time affects the heat input, as ultra-thin electrodes have fast heat conduction, the spot welding time needs to be controlled to avoid burn-through; center power ratio affects the energy distribution, adapting to the energy requirements of small-sized electrodes. All parameters need to be adjusted in tandem to avoid welding defects caused by abnormalities in a single parameter, ensuring welding accuracy and stability. ③ Welding trajectory selection: Circular wire welding, circular oscillating welding, spiral wire welding or circular modified into spot welding trajectory can be used. Circular modified into spot welding trajectory is preferred. This trajectory can effectively improve the weld formation quality, reduce defects such as spatter and collapse, and has high trajectory accuracy. It is suitable for the ring welding requirements of ultra-thin small-sized poles in the new energy industry of 3C industry, ensuring that the weld is evenly distributed around the pole and meets the requirements of conductivity and appearance. ④ Determination of Optimal Parameters: Through single-variable experimental optimization and combined with the mass production requirements of the 3C industry, the optimal welding parameter combination for ultra-thin small-size electrode posts of new energy in the 3C industry was determined to be: spot welding delay of 8000μs, spot spacing of 0.03mm, spot welding time of 0.4ms, center power ratio of 26%~32%, and outer ring power ratio of 80%. Under these parameter conditions, the weld penetration uniformity δ is controlled at 1.1%~9.9%, the process window width reaches 6%, and the welding effect is optimal. It can effectively avoid defects such as burn-through and incomplete penetration during the welding of ultra-thin small-size electrode posts. Moreover, the parameters have strong fault tolerance and are suitable for the mass production requirements of the 3C industry, and can be directly applied. (5) Weld quality evaluation method: After welding, the sample is cut, inlaid, ground, polished and etched in sequence. The surface quality of the weld is observed under a microscope and the penetration depth is measured. The penetration depth uniformity δ and the process window width W are used. p When evaluating welding quality, a weld is considered qualified if the penetration depth is between 100 and 200 μm and there are no surface defects.

[0007] ① Specific sample preparation process: The sample is cut with a grinding wheel to remove excess parts and avoid cutting damage to small-sized poles and welds; the cut sample is placed in a metallographic mounting machine and mounted under pressure at 130℃ for 15 minutes to facilitate subsequent grinding and polishing; the mounted sample is ground and polished with a grinding and polishing machine until the sample surface is smooth and free of scratches to ensure the clarity of microscopic observation; the sample is etched with a mixed solution of FeCl3 and HCl to expose the weld cross-section, which facilitates the observation and measurement of the penetration depth and forming quality of small-sized welds.

[0008] ② Evaluation methods and standards: Microscopic observation of weld surface and cross-sectional quality, and measurement of key parameters such as weld penetration depth are used to ensure evaluation accuracy is suitable for the measurement needs of small-sized welds; weld penetration uniformity δ and process window width W are used. p To evaluate welding quality, among which , in the formula, D p The measured value representing the penetration depth (unit: μm); max D p Indicates the maximum penetration depth (unit: μm); min D p Indicates the minimum penetration depth (unit: μm); D p均 This represents the average melting depth (unit: μm).

[0009] In the formula, P max Represents the maximum permissible power (unit: W); P min Represents the minimum permissible power (unit: W); P nom This is the nominal power of the laser (unit: W), which is 500W in this experiment.

[0010] When the penetration depth falls to 100~200μm and there are no defects such as pores, spatter, or collapse on the surface, it is judged as a qualified weld and fully meets the quality standards of new energy products in the 3C industry.

[0011] As an improvement to the method for characterizing the penetration depth and improving the quality of ultrathin micro-sized electrode ring laser welding of the present invention, the optimal process parameters for ring laser welding in step (4) are: spot delay of 8000μs, spot spacing of 0.03mm, spot welding time of 0.4ms, center power ratio of 26%~32%, and outer ring power ratio of 80%. This parameter combination is specifically adapted to welding ultrathin small-sized aluminum alloy electrodes with a diameter of 2mm and a thickness of 0.2mm, and has the best welding accuracy and stability. The laser is a ring 500 / 500W laser, the field lens is an F100 collimating / F254 field lens, and the galvanometer is a Raylase fourth-generation 20 galvanometer.

[0012] As an improvement to the method for characterizing the melting depth and improving the quality of ultra-thin micro-sized pole ring laser welding of the present invention, the laser welding control system described in step (1) can be equipped with a QCW150 laser to compare and verify the rationality of the ring laser welding parameters for adapting to the ultra-thin small-sized pole of new energy in the 3C industry and the welding effect.

[0013] As an improvement to the method for characterizing and improving the quality of ultrathin micro-sized pole ring laser welding in this invention, the calculation method for the uniformity of the weld depth δ in step (5) is: δ=(maxD p -minD p ) / D p均 ×100%, where D p For the measured melt depth, maxD p For the maximum melting depth, minD p For minimum melting depth, D p All values ​​represent average melt depth, in μm; process window width W p The calculation method for W is as follows: p =(P max -P min ) / =P nom ×100%, where P max For the maximum allowable power, P min For the minimum allowable power, P nom The laser has a nominal power of 500W, and this evaluation standard is adapted to the welding quality requirements of ultra-thin and small-sized electrodes in the new energy industry of the 3C industry.

[0014] As an improvement to the method for characterizing the penetration depth and improving the quality of ultrathin micro-sized pole ring laser welding in this invention, the specific process of quality evaluation in step (5) is as follows: the sample is cut with a grinding wheel, and then inlaid after being held at 130°C for 15 minutes. After polishing until the surface is free of scratches, it is etched with a mixed solution of FeCl3 and HCl. The penetration depth is observed and measured using a Keyence VHX series microscope to ensure that the evaluation accuracy is adapted to the evaluation requirements of small-sized welds.

[0015] The beneficial effects of this invention are as follows: 1. Strong adaptability of process parameters, precisely matching the needs of the 3C industry: This invention is designed for the characteristics of ultra-thin small-sized electrode posts (2mm in diameter and 0.2mm in thickness) in the new energy industry of the 3C industry. It clarifies the range of suitable welding parameters and the optimal parameter combination, covering laser focus position, nitrogen protection parameters, welding core parameters, etc., which solves the problem of poor adaptability of traditional parameters and inability to meet the welding needs of small size. It ensures welding accuracy and stability, and the uniformity of penetration depth δ is controlled at 1.1%~9.9%, and the process window width reaches 6%, which is suitable for the precision requirements of 3C products.

[0016] 2. Highly targeted parameter optimization and effective defect control: Addressing the pain points of easy oxidation, burn-through, and weld misalignment of ultra-thin, small-sized electrodes in the 3C industry, the system optimizes core parameters such as dotting delay, dot spacing, and power ratio. Combined with standardized focus positioning methods and nitrogen protection processes, it effectively reduces defects such as weld collapse, spatter, oxidation, and incomplete penetration. The penetration depth fluctuation range is controlled within 100~200μm, meeting the appearance and performance requirements of 3C new energy products.

[0017] 3. Standardized operation method, suitable for mass production in the 3C industry: This invention details and standardizes each step of the process, including platform setup, workpiece preparation, focus positioning, welding operation, and quality evaluation. The parameter settings are simple and easy to understand, the operation is convenient, no complicated debugging is required, and the parameter fault tolerance is strong. It can adapt to the slight fluctuations in parameters during the mass production process in the 3C industry, reduce production difficulty and scrap rate, improve production efficiency, and can be directly applied to the mass production of ultra-thin small-size electrode posts for new energy in the 3C industry.

[0018] 4. High positioning accuracy, suitable for small-size welding needs: The CCD coaxial positioning system achieves micron-level precise positioning, which solves the problem of difficult and easy deviation in the coaxial positioning of ultra-thin and small-size poles in the 3C industry. It ensures the accurate position of the weld, avoids product scrap due to positioning deviation, improves the product qualification rate, and meets the development trend of miniaturization and precision of 3C products. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a laser welding experimental platform.

[0020] Figure 2 This is a schematic diagram of the cross-section of the laser welding of the pole and the cover plate.

[0021] Figure 3 This is a graph showing the variation of weld width at different z-axis heights.

[0022] Figure 4 These are weld formation diagrams under different dotting delays. Detailed Implementation

[0023] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments, detailing the welding process parameters and operation methods for ultra-thin, small-sized electrode posts adapted to the new energy sector in the 3C industry. This further verifies the rationality of the parameters and the feasibility of the methods, enabling those skilled in the art to implement the invention. All embodiments are specifically for ultra-thin, small-sized aluminum alloy electrode posts with a diameter of 2mm and a thickness of 0.2mm in the new energy sector of the 3C industry. The content mentioned in the embodiments is not intended to limit the present invention.

[0024] Example 1: As Figures 1-4 As shown, a method for characterizing the penetration depth and improving the quality of ultrathin micro-sized annular laser welding is described, with specific process steps and parameter control as follows: (1) Setting up a welding platform: The laser welding control system includes a ring 500 / 500W laser, an F100 collimating lens, an F254 field lens, a Raylase fourth-generation 20 galvanometer and a laser control card. The CCD coaxial positioning system uses a high-definition coaxial camera with a positioning accuracy of micron level, which is suitable for the positioning requirements of small-sized pole pieces.

[0025] (2) Workpiece preparation: 3-series aluminum alloy ultra-thin small-size pole (diameter 2mm, height 1.2mm, thickness 0.2mm) and cover plate (diameter 2mm, thickness 0.3mm) for new energy in the 3C industry. The chemical composition meets the requirements. They are connected and fixed by adapter plate and sealant to ensure a seamless fit.

[0026] (3) Laser focus positioning: Within the Z-axis range of 32.9mm to 35.7mm, a straight line is etched with a step of 0.2mm to determine the focus position at 34.3mm on the Z-axis, ensuring that the laser energy is accurately applied to the welding area of ​​the small-sized pole.

[0027] (4) Ring laser welding: Start CCD coaxial positioning and turn on 99.99% nitrogen protection; adopt the optimal process parameters adapted to the ultra-thin small-size pole of the 3C industry: spot delay 8000μs, spot spacing 0.03mm, spot welding time 0.4ms, center power ratio 29%, outer ring power ratio 80%; adopt circular deformation to form spot welding trajectory, start the welding program to complete the welding, and ensure that the weld is uniformly around the pole.

[0028] (5) Weld quality evaluation method: Cut according to specifications, inlay at 130℃ for 15 minutes, grind and polish, corrode with FeCl3 and HCl mixed solution; no defects are observed under a microscope, and the maximum penetration depth (maxD) is measured. p =168.5μm, minD p =152.3μm, D p均 =160.4μm, δ≈5.1%, W p =6%, melting depth 160.4μm, meets the quality standards for new energy products in the 3C industry, and is qualified.

[0029] ① Specific sample preparation process: The sample is cut with a grinding wheel to remove excess parts and avoid cutting damage to small-sized poles and welds; the cut sample is placed in a metallographic mounting machine and mounted under pressure at 130℃ for 15 minutes to facilitate subsequent grinding and polishing; the mounted sample is ground and polished with a grinding and polishing machine until the sample surface is smooth and free of scratches to ensure the clarity of microscopic observation; the sample is etched with a mixed solution of FeCl3 and HCl to expose the weld cross-section, which facilitates the observation and measurement of the penetration depth and forming quality of small-sized welds.

[0030] ② Evaluation methods and standards: Microscopic observation of weld surface and cross-sectional quality, and measurement of key parameters such as weld penetration depth are used to ensure evaluation accuracy is suitable for the measurement needs of small-sized welds; weld penetration uniformity δ and process window width W are used. p To evaluate welding quality, among which , in the formula, D p The measured value representing the penetration depth (unit: μm); max D p Indicates the maximum penetration depth (unit: μm); min D p Indicates the minimum penetration depth (unit: μm); D p均 This represents the average melting depth (unit: μm).

[0031] In the formula, P max Represents the maximum permissible power (unit: W); P min Represents the minimum permissible power (unit: W); P nom This is the nominal power of the laser (unit: W), which is 500W in this experiment.

[0032] When the penetration depth falls to 100~200μm and there are no defects such as pores, spatter, or collapse on the surface, it is judged as a qualified weld and fully meets the quality standards of new energy products in the 3C industry.

[0033] Appendix Figure 4The weld formation diagrams are shown in the figures for different dotting delays, where (a) is the weld formation diagram formed with a dotting delay of 3000 μs; (b) is the weld formation diagram formed with a dotting delay of 4000 μs; (c) is the weld formation diagram formed with a dotting delay of 5000 μs; (d) is the weld formation diagram formed with a dotting delay of 6000 μs; (e) is the weld formation diagram formed with a dotting delay of 7000 μs; (f) is the weld formation diagram formed with a dotting delay of 8000 μs; (g) is the weld formation diagram formed with a dotting delay of 9000 μs; and (h) is the weld formation diagram formed with a dotting delay of 10000 μs.

[0034] Example 2 (Optimal parameter range verification, adapted to 3C batch fluctuations) This embodiment operates in the same way as Embodiment 1, except that the welding parameters are adjusted as follows: spot welding delay 8000μs, spot spacing 0.03mm, spot welding time 0.4ms, center power ratio 26%, outer ring power ratio 80%, to adapt to the slight fluctuations in parameters during 3C mass production.

[0035] Evaluation result: No defects in the weld, maximum penetration depth D p =158.2μm, minD p =143.5μm, D p均 =150.8μm, δ≈9.7%, W p =6%, melting depth 150.8μm, meets the quality standards for new energy products in the 3C industry, verifies the effectiveness and fault tolerance of this parameter range, and is suitable for mass production.

[0036] Example 3 (Optimal parameter range verification, adapted to 3C precision requirements) This embodiment operates in the same way as Embodiment 1, except that the welding parameters are adjusted as follows: spot welding delay 8000μs, spot spacing 0.03mm, spot welding time 0.4ms, center power ratio 32%, outer ring power ratio 80%, to meet the higher precision welding requirements of 3C products.

[0037] Evaluation result: No defects in the weld, maximum penetration depth D p =172.6μm, minD p =166.8μm, D p均 =169.7μm, δ≈3.4%, W p =6%, melting depth 169.7μm, meets the quality standards for new energy products in the 3C industry, further verifying the stability and high-precision adaptability of the parameter range.

[0038] Comparison scale (traditional parameter comparison, not suitable for small-size 3C products) Using the traditional QCW laser welding method, ultra-thin small-sized electrode posts with a diameter of 2mm and a thickness of 0.2mm in the new energy sector of the 3C industry are welded. The operation method is basically the same as that of this invention, except that the welding parameters are: power 50%, speed 300mm / s, no nitrogen protection, no clear focus positioning parameters, and no optimization for small-sized electrode posts.

[0039] Evaluation results: The weld surface collapsed and spatter appeared; the weld width difference was 0.07 mm; the maximum penetration depth was [not specified]. p =152.2μm, minD p =118.3μm, D p均 =135.25μm, δ=25.06%, W p =0, which does not meet the quality standards for new energy products in the 3C industry and is therefore unqualified; comparative analysis shows that the optimized process parameters and standardized operation of this invention are specifically adapted to the welding requirements of ultra-thin small-sized poles in the new energy industry of the 3C industry, which can significantly improve the welding quality and solve the pain point that traditional methods cannot adapt.

[0040] The above embodiments and comparative examples demonstrate that, by addressing the dimensional characteristics of ultra-thin, small-sized electrode posts (2mm in diameter and 0.2mm in thickness) for new energy products in the 3C industry, this invention clarifies the appropriate range of welding process parameters, optimizes the optimal parameter combination, and standardizes the operation methods for each step. This enables high-precision and high-stability welding of such electrode posts, with controllable parameters, convenient operation, and stable welding results. It can be directly applied to the mass production of new energy products in the 3C industry, effectively solving the problems of poor parameter adaptability, insufficient welding precision, and numerous defects in traditional welding methods. This meets the core needs of miniaturization, precision, and mass production of new energy products in the 3C industry.

[0041] The above embodiments are preferred implementations of the present invention. In addition, the present invention can be implemented in other ways. Any obvious substitutions without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A method for characterizing the penetration depth and improving the quality of ultrathin micro-sized annular laser welding, characterized in that, Includes the following steps: (1) Building a welding platform: The welding platform is a precision platform adapted to the welding of ultra-thin small-sized poles in the new energy industry of 3C industry. It consists of a laser welding control system and a CCD coaxial positioning system. The laser welding control system includes a ring laser, a field lens, a galvanometer and a laser control card. The CCD coaxial positioning system is used to achieve high-precision coaxial positioning of the ultra-thin small-sized pole and the cover plate and to transmit position information to the laser welding control system. (2) Workpiece preparation: The workpieces to be welded are aluminum alloy ultra-thin small-sized poles and cover plates. The aluminum alloy ultra-thin small-sized poles are ultra-thin small-sized structures with a diameter of 2mm, a height of 1.2mm, and a thickness of 0.2mm. The cover plates are 2mm in diameter and 0.3mm in thickness, which are adapted to the pole size. The aluminum alloy ultra-thin small-sized poles and cover plates are connected and fixed by adapter plates and sealant to ensure that there is no gap between them and avoid welding defects caused by fit deviation of small-sized structures. (3) Laser focus positioning method: The weld width minimization criterion is adopted. In the Z-axis height range of 32.9mm~35.7mm, a straight line with a length of 20mm is etched by a ring laser in a step of 0.2mm. The width of each straight line is measured to determine the laser focus position as 34.3mm on the Z-axis. Subsequent welding is carried out at this focus position to ensure that the welding energy is accurately applied to the welding area of ​​the small-sized pole piece. (4) Ring laser welding process and parameter control: Start the CCD coaxial positioning system to complete the high-precision coaxial positioning of the ultra-thin small-sized pole and the cover plate, turn on 99.99% nitrogen protection to avoid oxidation during welding of ultra-thin poles; adjust the welding parameters of the ring laser and start the welding program. The welding parameters are the precise parameters adapted to ultra-thin small-sized poles: the spot delay is set to 3000~10000μs, the spot spacing is set to 0.025~0.040mm, the spot welding time is set to 0.2~0.5ms, and the center power ratio is 24%~36%; the welding trajectory adopts circular line welding, circular oscillating welding, spiral line welding or circular transformation into spot welding trajectory, preferably circular transformation into spot welding trajectory, to adapt to the ring welding requirements of small-sized poles and improve welding accuracy; (5) Weld quality evaluation method: After welding, the sample is cut, inlaid, ground, polished and etched in sequence. The surface quality of the weld is observed under a microscope and the penetration depth is measured. The penetration depth uniformity δ and the process window width W are used. p When evaluating welding quality, a weld is considered qualified if the penetration depth is between 100 and 200 μm and there are no surface defects.

2. The method for characterizing and improving the penetration depth of ultrathin micro-sized annular laser welding according to claim 1, characterized in that, The optimal process parameters for ring laser welding in step (4) are: spot delay 8000μs, spot spacing 0.03mm, spot welding time 0.4ms, center power ratio 26%~32%, and outer ring power ratio 80%. This parameter combination is specifically adapted to welding ultra-thin small-sized aluminum alloy poles with a diameter of 2mm and a thickness of 0.2mm, and has the best welding accuracy and stability. The laser is a ring 500 / 500W laser, the field lens is an F100 collimating / F254 field lens, and the galvanometer is a Raylase fourth-generation 20 galvanometer.

3. The method for characterizing and improving the penetration depth of ultrathin micro-sized annular laser welding according to claim 1, characterized in that, The laser welding control system described in step (1) can be equipped with a QCW150 laser to compare and verify the rationality of the ring laser welding parameters for adapting to the ultra-thin small-sized poles of new energy in the 3C industry and the welding effect.

4. The method for characterizing and improving the penetration depth of ultrathin micro-sized annular laser welding according to claim 1, characterized in that, The calculation method for the melting depth uniformity δ mentioned in step (5) is: δ=(maxD p -minD p ) / D p均 ×100%, where Dp is the measured melt depth, and maxD p For the maximum melting depth, minD p For minimum melting depth, D p All values ​​represent average melt depth, in μm; process window width W p The calculation method for W is as follows: p =(p max -p min ) / p nom ×100%, where p max For the maximum allowable power, p min For the minimum allowable power, p nom The laser has a nominal power of 500W, and this evaluation standard is adapted to the welding quality requirements of ultra-thin and small-sized electrodes in the new energy industry of the 3C industry.

5. The method for characterizing and improving the penetration depth of ultrathin micro-sized annular laser welding according to claim 1, characterized in that, The specific process for quality evaluation in step (5) is as follows: the sample is cut with a grinding wheel, inlaid after being held at 130°C for 15 minutes, polished until the surface is free of scratches, etched with a mixed solution of FeCl3 and HCl, and the penetration depth is observed and measured with a microscope to ensure that the evaluation accuracy is adapted to the evaluation requirements of small-sized welds.

6. The method for characterizing and improving the penetration depth of ultrathin micro-sized annular laser welding according to claim 1, characterized in that, The specific process for sample treatment in step (5) is as follows: the sample is cut with a grinding wheel to remove excess parts and avoid damage to small-sized poles and welds; the cut sample is placed in a metallographic mounting machine and mounted under pressure at 130°C for 15 minutes to facilitate subsequent grinding and polishing; the mounted sample is ground and polished with a grinding and polishing machine until the sample surface is smooth and free of scratches to ensure the clarity of microscopic observation; the sample is corroded with a mixed solution of FeCl3 and HCl to expose the weld cross section, which facilitates observation and measurement of the penetration depth and forming quality of small-sized welds; Evaluation methods and standards: Keyence VHX series microscopes were used to observe the surface and cross-sectional quality of the weld, and key parameters such as weld penetration depth were measured to ensure evaluation accuracy suitable for the measurement needs of small-sized welds. Welding quality was evaluated using weld penetration uniformity δ and process window width Wp. , in the formula, D p The measured value representing the penetration depth, in μm; max D p Indicates the maximum melting depth, in μm; min D p Indicates the minimum penetration depth, in μm; D p均 This represents the average melting depth, in μm. In the formula, P max Represents the maximum permissible power, unit: W; P min Represents the minimum permissible power, in watts (W). P nom This is the nominal power of the laser, in W; in this experiment, it is 500W. When the penetration depth falls to 100~200μm and there are no defects such as pores, spatter, or collapse on the surface, it is judged as a qualified weld and fully meets the quality standards of new energy products in the 3C industry.

7. The method for characterizing and improving the penetration depth of ultrathin micro-sized annular laser welding according to claim 1, characterized in that, The specific steps of the ring laser welding in step (4) are as follows: ① Preparation before welding: Activate the CCD coaxial positioning system to capture the position information of the ultra-thin small-sized electrode post and the cover plate, adjust the workpiece position to make the two coaxial, and achieve a positioning accuracy of micron level to ensure accurate welding position and avoid weld seam offset during welding of small-sized electrode posts; turn on 99.99% nitrogen protection. Since the new energy electrode posts in the 3C industry are thin and easily oxidized during welding, nitrogen protection can effectively prevent aluminum alloy oxidation, avoid weld seam defects caused by oxidation, ensure the stability of welding quality, and adapt to the appearance and performance requirements of 3C products; ② Welding Parameter Range Setting: Considering the size characteristics of ultra-thin small-sized electrodes in the 3C industry, the annular laser welding parameter range is determined as follows: spot delay 3000~10000μs, spot spacing 0.025~0.040mm, spot welding time 0.2~0.5ms, and center power ratio 24%~36%. The parameter adjustment principles are as follows: spot delay affects the weld overlap width, adapting to the annular weld requirements of small-sized electrodes to avoid excessively wide or narrow overlaps; spot spacing affects the uniformity of penetration depth, as the welding area of ​​small-sized electrodes is narrow, the spot spacing needs to be precisely controlled to ensure effective fusion of the molten pool without over-melting; spot welding time affects the heat input, as ultra-thin electrodes have fast heat conduction, the spot welding time needs to be controlled to avoid burn-through; center power ratio affects the energy distribution, adapting to the energy requirements of small-sized electrodes. All parameters need to be adjusted in tandem to avoid welding defects caused by abnormalities in a single parameter, ensuring welding accuracy and stability. ③ Welding trajectory selection: adopt circular wire welding, circular oscillating welding, spiral wire welding or circular modified into spot welding trajectory, with circular modified into spot welding trajectory being preferred; ④ Determination of optimal parameters: Through single-variable experimental optimization and combined with the mass production requirements of the 3C industry, the optimal welding parameter combination for the ultra-thin small-size electrode column of new energy in the 3C industry was determined to be: spot welding delay of 8000μs, spot spacing of 0.03mm, spot welding time of 0.4ms, center power ratio of 26%~32%, and outer ring power ratio of 80%. Under these parameter conditions, the weld penetration uniformity δ is controlled at 1.1%~9.9%, and the process window width reaches 6%.

8. The method for characterizing and improving the penetration depth of ultrathin micro-sized annular laser welding according to claim 1, characterized in that, The laser focus is located using the weld width minimization criterion in step (3). The weld width minimization criterion is based on the Gaussian beam propagation characteristics, and the relationship is: Where W(z) is the beam diameter at the defocus point Z, W0 is the beam waist diameter, and λ is the laser wavelength. W(z) is minimum when z=0, which is the focal point. The specific operation method is as follows: Place a black metal business card on the experimental table, use the same laser process parameters as the actual welding, and within the Z-axis height range of 32.9mm~35.7mm, etch a straight line with a length of 20mm in 0.2mm increments. A total of 15 sets of experiments were carried out. By measuring the width of each straight line, the minimum etch width was determined at Z-axis 34.3mm, which is the laser focal point. All subsequent welding tests were carried out at this focal point.

Images