Welding device and method for welding small-size metal sheet and metal structural part

Abstract

The invention relates to a welding method and device for a small-size metal sheet and a metal structural part, and belongs to the technical field of metal welding. The problems of low welding precision, unstable quality and the like exist in welding of small-size metal sheets and metal structural parts. The method comprises the steps of fixing a metal sheet through vacuum adsorption, clamping a metal structural part through a piezoelectric ceramic fine adjustment clamp, monitoring the temperature through infrared temperature measurement to trigger pulse laser welding, applying axial vibration, and combining argon protection, two-stage cooling, detection finishing and the like. Meanwhile, a matched welding device is provided. The method and the device can effectively improve the welding precision and quality, and are mainly used for welding small-size metal sheets and metal structural parts in the field of microsensors.

Description

Technical Field

[0001] The present invention relates to the technical field of metal processing and welding. More specifically, the present invention relates to a welding device and method for welding small-sized metal sheets and metal structural parts. Background Art

[0002] In modern manufacturing, especially in the field of manufacturing precision electronic devices such as micro sensors, the welding of small-sized metal sheets and metal structural parts is a key process. When dealing with the welding of small-sized metal parts using traditional welding methods, there are many problems. For example, during the process of fixing the metal sheet and the metal structural part, it is difficult to precisely control the clamping force with conventional mechanical clamping methods. Excessive clamping force is likely to cause deformation of the metal part, while too small clamping force will cause the part to displace during the welding process, affecting the welding precision.

[0003] During the welding process, temperature control is an important factor affecting the welding quality. Existing welding processes often cannot accurately monitor the temperature of the welding area, resulting in too high or too low welding temperature. Too high temperature will cause over-melting of the metal part, change the metal's organizational structure, and reduce the part's performance; too low temperature will cause insecure welding, such as false soldering and de-soldering. Moreover, ordinary welding equipment cannot achieve precise energy control and stable welding parameters when welding small-sized metal parts, making it difficult to ensure the consistency of welding quality.

[0004] The cooling process after welding is also crucial. Traditional cooling methods cannot effectively control the cooling rate and cooling uniformity, and are prone to generating thermal stress inside the metal part, resulting in part deformation or even cracking. At the same time, there are no effective means for detecting and trimming the flatness of the welding seam, making it difficult to meet the strict requirements for welding precision of precision devices such as micro sensors. These problems seriously restrict the improvement of the welding quality of small-sized metal sheets and metal structural parts, and there is an urgent need for a new welding method and device to solve these technical problems.

[0005] In the field of micro sensor technology: small-sized metal sheet: usually refers to a metal thin sheet with a specific shape and size, and relatively small size. Generally speaking, its length and width may be between a few millimeters and dozens of millimeters, and the thickness may be between a fraction of a millimeter and a few millimeters. These metal sheets often have precise shape and size requirements for realizing specific functions in micro sensors, such as being used as sensitive elements, electrodes, connecting components, etc. For example, in a pressure sensor, there may be small-sized metal strain gauges, which are connected to the elastic body of the sensor by pasting or welding. When the elastic body is deformed under pressure, the resistance value of the metal strain gauge will change, thus converting the pressure signal into an electrical signal. Another example is that in some micro temperature sensors, small-sized metal thermistor sheets are used to sense temperature changes.

[0006] Metal structural components: Generally refers to metal components that constitute the overall structure of a microsensor or play roles such as support and fixation. Their dimensions are generally larger than those of small-sized metal sheets, and their structures are more complex. It can be a bracket, housing, base, etc. with certain shapes and precision requirements, providing mechanical support and protection for other components in the microsensor to ensure that each component maintains the correct relative position and stability during operation. For example, the metal frame in a micro-accelerometer is used to fix the sensitive element and other electronic components of the sensor, enabling them to accurately sense and output corresponding signals when subjected to acceleration. Another example is the metal housing of some gas sensors, which not only protects the internal sensitive elements but may also have functions such as heat dissipation and shielding external interference. Summary of the Invention

[0007] An object of the present invention is to solve at least the above problems and provide at least the advantages described hereinafter.

[0008] To achieve these objects and other advantages of the present invention, a welding method for small-sized metal sheets and metal structural components is provided, including the following steps: Fix the metal sheet through a vacuum adsorption table, and set the vacuum adsorption pressure to 0.05 - 0.08 MPa; Clamp the metal structural component with a fixture equipped with a piezoelectric ceramic fine adjuster, and control the clamping force within the range of 5 - 8 N; Use an infrared thermometer to monitor the temperature of the contact area between the metal sheet and the metal structural component in real time. When the temperature of the contact area reaches 80 - 100 °C, start the pulsed laser welding equipment; Apply axial vibration to the metal structural component through the piezoelectric ceramic fine adjuster, with an amplitude of 2 - 5 μm and a vibration frequency of 50 - 100 Hz; After welding is completed, purge the welding area with argon as the protective gas; Transfer the welded assembly to a two-stage cooling station for cooling; Use a white light interferometer to detect the flatness of the weld seam. When the height difference of the seam exceeds 2 μm, trigger the numerical control grinding device to trim the raised part.

[0009] Preferably, the parameters of the pulsed laser welding equipment are set as follows: laser wavelength is 1064 nm, single pulse energy is 3 - 5 J, pulse width is 2 - 4 ms, pulse frequency is 10 - 15 Hz, and spot diameter is 0.1 - 0.3 mm.

[0010] Preferably, the defocus amount of the pulsed laser welding is set to +0.3~+0.4 mm, the front edge rising time of the laser pulse waveform is 1.5 - 2 ms, the trailing edge falling time ≤ 0.8 ms, and the laser power drops below 10% of the peak power within the adjacent pulse interval time.

[0011] Preferably, the grinding depth of the numerically controlled grinding device is set to 1 - 3 μm, the grinding speed is 200 - 300 r / min, the argon gas flow rate is controlled at 8 - 12 L / min, and the purging time is 20 - 30 seconds.

[0012] Preferably, for the first - stage cooling of the two - stage cooling station, a semiconductor refrigerating sheet is used for contact cooling, the temperature of the cooling surface is maintained at 10 - 15 °C, and the continuous cooling time is 60 - 90 seconds; for the second - stage cooling, aerosol - mist mixed cooling is used, the compressed air pressure is 0.3 - 0.5 MPa, the particle size of the atomized water droplets is 20 - 50 μm, and the cooling time is 30 - 45 seconds.

[0013] Preferably, the cooling rate of the semiconductor refrigerating sheet in the first - stage cooling is controlled at 0.5 - 0.8 °C / s; in the aerosol - mist mixed medium of the second - stage cooling, the volume ratio of water droplets to air is 1:15 - 1:20, and the angle between the aerosol jet direction and the welding plane is 45 - 60°.

[0014] Preferably, the vibration waveform of the piezoelectric ceramic fine - adjuster is a rectangular wave with a duty cycle of 30 - 50%, and the vibration phase is synchronized with the rising edge of the pulsed laser, and the synchronization time deviation is less than 1 ms.

[0015] Preferably, the vacuum adsorption hole array is divided into three circles from the inside to the outside. The inner - circle hole diameter is 0.3 - 0.5 mm, the middle - circle hole diameter is 0.2 - 0.3 mm, and the outer - circle hole diameter is 0.1 - 0.2 mm; the distances between adjacent hole circles are 2 mm, 1.5 mm, and 1 mm respectively, and the included angle between the center - line connections of adjacent layer holes is 22.5°.

[0016] Preferably, the clamping surface of the fixture is covered with a polyimide insulating layer. The thickness of the polyimide insulating layer is 0.2 - 0.5 mm, the surface is formed with grid - like patterns by laser etching, the pattern depth is 5 - 8 μm, and the grid density is 20 - 30 lines / mm; at 25 °C and a normal load of 5 N, the static friction coefficient between the insulating layer and the metal structural part is controlled within the range of 0.4 - 0.6, and the volume resistivity at 200 °C is ≥1×10 14 Ω·cm.

[0017] Provided is a welding device for small - size metal sheets and metal structural parts in the field of micro - sensors, including: A vacuum adsorption table, on the surface of which there is a vacuum adsorption hole array. The vacuum adsorption table is connected to a vacuum pump, and the vacuum pump pressure control module sets the adsorption pressure to 0.05 - 0.08 MPa; A piezoelectric ceramic fine - adjust fixture, which includes jaws for clamping the metal structural part, a polyimide insulating layer covering the contact surface of the jaws, a piezoelectric ceramic driver, and a clamping - force sensor. The clamping - force sensor is electrically connected to the piezoelectric ceramic driver to control the clamping force to be 5 - 8 N; An infrared temperature measurement module, which includes an infrared thermometer with a focused spot diameter of 0.5 - 0.8 mm. The optical axis of the infrared thermometer is aligned with the center of the welding area, and the temperature measurement range is 50 - 150 °C; A pulsed laser welding device, at the light path outlet of which there is a laser focusing lens group with a wavelength of 1064 nm. The focal length adjustment mechanism of the laser focusing lens group is coaxially arranged with the vibration direction of the piezoelectric ceramic fine-tuning fixture; A vibration control module, which includes a vibration generator and a frequency controller connected to the piezoelectric ceramic fine-tuning fixture. The amplitude of the axial vibration output by the vibration generator is 2 - 5 μm, and the vibration frequency is 50 - 100 Hz; An argon protection unit, which includes a gas nozzle surrounding the welding area, an argon flow control valve, and an argon gas source. The spraying direction of the gas nozzle forms an angle of 30 - 45° with the welding plane; A two-stage cooling station, which includes a first-stage semiconductor refrigeration sheet contact cooling module and a second-stage aerosol mixing cooling module. The temperature controller of the refrigerating surface of the first-stage cooling module is set to 10 - 15 °C. The second-stage cooling module includes a compressed air source, an atomizing nozzle, and a water droplet particle size controller. The compressed air pressure is set to 0.3 - 0.5 MPa, and the atomized water droplet particle size is controlled to be 20 - 50 μm; A detection and trimming unit, which includes a white light interferometer and a numerically controlled grinding device. The optical probe of the white light interferometer is perpendicularly arranged to the welding seam plane, and the detection accuracy is 0.1 μm. The axial feed accuracy of the grinding head of the numerically controlled grinding device is 1 μm, and the radial rotation speed is controlled to be 200 - 300 r / min; A central control module, which is electrically connected to a vacuum pump pressure control module, a clamping force sensor, an infrared thermometer, a pulsed laser welding device, a vibration control module, an argon flow control valve, a two-stage cooling station, and a detection and trimming unit respectively. The central control module triggers the pulsed laser welding according to the signal of the infrared thermometer, and controls the start and stop of the numerically controlled grinding device according to the detection result of the white light interferometer.

[0018] The present invention has at least the following beneficial effects: First, through precise vacuum adsorption to fix the metal sheet and reasonable fixture clamping of the metal structural part, the position accuracy of the welded parts is ensured; real-time infrared temperature measurement monitors the temperature and accurately triggers laser welding to ensure the appropriate welding temperature; the application of axial vibration improves the weld formation; argon protection prevents oxidation of the welding area; two-stage cooling effectively controls the cooling process and reduces thermal stress; detection and trimming ensure the flatness of the welding seam. Thus, the welding quality and accuracy of small-sized metal sheets and metal structural parts are comprehensively improved.

[0019] Second, reasonably set the parameters of the pulsed laser welding equipment so that parameters such as laser wavelength, energy, pulse width, frequency, and spot diameter cooperate with each other, enabling precise control of the welding energy input, achieving a stable welding process, and improving the strength and quality consistency of the welded joint.

[0020] Third, optimizing parameters such as the defocus amount and pulse waveform of pulsed laser welding helps to improve the penetration depth, width, and forming quality of the weld seam, reduce welding defects, enhance the stability and reliability of welding, and enable the welded joint to meet the high-precision usage requirements.

[0021] Fourth, appropriate grinding parameters of the numerical control grinding device and argon protection parameters can precisely trim the welding seam, remove the protruding parts, and ensure the flatness of the seam; meanwhile, argon protection effectively prevents oxidation of the welding area after welding, improving the performance and service life of the welded parts.

[0022] Fifth, the setting of the two-stage cooling method and parameters, through the combination of contact cooling with a semiconductor refrigeration sheet and aerosol mixing cooling, realizes rapid and uniform cooling of the welding assembly, effectively reducing the thermal stress inside the metal parts, reducing the generation of deformation and cracks, improving the dimensional accuracy and mechanical properties of the welded parts, and ensuring that the welded metal parts meet the high-precision usage requirements.

[0023] Sixth, precisely controlling the cooling rate of the semiconductor refrigeration sheet and reasonably adjusting the volume ratio and spraying angle of water droplets to air in aerosol mixing cooling further optimize the cooling process. This makes the cooling more uniform and efficient, can better eliminate the thermal stress generated in the metal parts during welding, avoid deformation and quality defects caused by uneven cooling, and thus improve the overall quality and reliability of the welded parts.

[0024] Seventh, the precise synchronization of the vibration waveform and phase of the piezoelectric ceramic fine adjuster with the pulsed laser can effectively improve the microscopic structure and forming quality of the weld seam during welding. Through vibration, it promotes the flow and mixing of the molten pool, reduces the generation of welding defects such as pores and inclusions, improves the strength and toughness of the welded joint, and enhances the stability and reliability of welding.

[0025] Eighth, a specifically designed vacuum adsorption hole array can form a uniform and stable vacuum adsorption force on the surface of the metal sheet by reasonably setting the aperture, spacing, and hole position angle of different circles. This enables the metal sheet to be firmly fixed during welding, avoiding displacement caused by insufficient adsorption, thereby improving the welding precision and ensuring the consistency of welding quality.

[0026] Ninth, the polyimide insulation layer on the clamping surface of the fixture and its special treatment not only ensure good insulation performance, prevent problems such as short circuits during welding, but also provide a stable and appropriate clamping force by optimizing the surface texture and friction coefficient. While ensuring the firm fixation of metal structural parts, it avoids damage to components caused by excessive clamping force, ensuring the stability of the welding process and the quality of welded parts.

[0027] Other advantages, objectives and features of the present invention will be partially reflected by the following description and partially understood by those skilled in the art through research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a layout schematic diagram of a welding device for one technical solution of the present invention; Figure 2 It is a schematic diagram of a control method for a two-stage cooling station for one technical solution of the present invention.

[0029] Reference numerals in the specification drawings: metal sheet 1, vacuum adsorption table 2, fixture 3, infrared thermometer 4, pulsed laser welding equipment 5. DETAILED DESCRIPTION OF THE INVENTION

[0030] The following further describes the present invention in detail with reference to the drawings, so that those skilled in the art can implement it according to the description in the specification.

[0031] It should be noted that the experimental methods described in the following embodiments are all conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified; in the description of the present invention, the orientation or positional relationship indicated by the terms is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation to the present invention.

[0032] As Figures 1 - 2 shown, the present invention provides a welding method for small-sized metal sheets and metal structural parts, including the following steps: Fix the metal sheet 1 through the vacuum adsorption table 2, and set the vacuum adsorption pressure to 0.05 - 0.08 MPa; Clamp the metal structural part through the fixture 3 with a piezoelectric ceramic micro-adjuster, and control the clamping force within the range of 5 - 8 N; Use the infrared thermometer 4 to monitor the temperature of the contact area between the metal sheet 1 and the metal structural part in real time. When the temperature of the contact area reaches 80 - 100 °C, start the pulsed laser welding equipment 5; An axial vibration is applied to the metal structural part through a piezoelectric ceramic micro-adjuster, with an amplitude of 2 - 5 μm and a vibration frequency of 50 - 100 Hz; After welding is completed, argon is used as a shielding gas to purge the welding area; Transfer the welded assembly to a two-stage cooling station for cooling; Use a white light interferometer to detect the flatness of the welded seam. When the height difference of the seam exceeds 2 μm, trigger the numerical control grinding device to trim the raised part.

[0033] In the above technical solution, from the fixation before welding, to the welding process control, and then to the post-welding treatment, each link works synergistically to effectively solve the problem of welding small-sized metal sheets to metal structural parts, and is applicable to the welding of materials such as stainless steel, aluminum alloy, titanium alloy, copper and copper alloys, silver-based materials, nickel-based alloys, gold, platinum and their alloys.

[0034] A vacuum adsorption table is used to fix the metal sheet, and the vacuum adsorption pressure is set at 0.05 - 0.08 MPa. Compared with traditional mechanical clamping, this pressure range can not only provide sufficient adsorption force to prevent the displacement of the metal sheet, but also avoid the deformation of the metal sheet caused by excessive pressure, ensuring the precise position of the metal sheet during welding. A fixture with a piezoelectric ceramic micro-adjuster fixes the metal structural part with a clamping force of 5 - 8 N. The piezoelectric ceramic micro-adjuster can achieve micro-displacement adjustment, controlling the relative position error between the metal structural part and the metal sheet within an extremely small range, laying a foundation for high-quality welding.

[0035] An infrared thermometer is used to monitor the temperature of the welding area in real time. When the temperature reaches 80 - 100 °C, start the pulsed laser welding equipment. This temperature range is an appropriate welding temperature interval verified by experiments, which can avoid problems such as insufficient fusion or excessive burning and deformation of the metal caused by too low or too high temperature. During the welding process, the piezoelectric ceramic micro-adjuster applies an axial vibration with an amplitude of 2 - 5 μm and a frequency of 50 - 100 Hz, which can promote the flow and mixing of the metal in the welding molten pool, reduce defects such as pores and inclusions, refine the grain structure of the weld seam, and improve the strength and toughness of the weld seam.

[0036] After welding is completed, argon purging can form an inert gas protection layer on the surface of the welding area to prevent the oxidation reaction of the metal with oxygen in the air at high temperature, ensuring the corrosion resistance of the welded joint. The setting of the two-stage cooling station, combining the contact cooling of the first-stage semiconductor refrigeration sheet and the aerosol mixing cooling of the second stage, can precisely control the cooling rate and cooling uniformity, effectively reducing the internal thermal stress of the metal component and reducing the generation of deformation and cracks. The cooperation of the white light interferometer detection and the numerical control grinding device trimming can control the height difference of the welded seam within an extremely small range, meeting the strict requirements for welding accuracy in precision fields such as micro-sensors, and significantly improving the dimensional accuracy and surface quality of the welded components.

[0037] Specifically, for the vacuum adsorption and fixation of metal sheets, the vacuum adsorption pressure can be set to 0.05 MPa, 0.06 MPa, 0.07 MPa, or 0.08 MPa; the pore size distribution of the vacuum adsorption hole array is 0.3 - 0.5 mm in the inner circle, 0.2 - 0.3 mm in the middle circle, and 0.1 - 0.2 mm in the outer circle. A vacuum pump of model R5 RA 0023 C from Busch company can be used, and a multi-ring annular distribution of vacuum adsorption hole arrays can be set on the surface of the adsorption table. The material of the adsorption table can be selected as 6061 aluminum alloy, with a hard anodized layer on the surface, and the thickness is 10 - 15 μm. The vacuum adsorption table is installed on the horizontal reference plane of the welding workbench and is connected to the vacuum pump through a vacuum pipeline. The opening of the solenoid valve is feedback-regulated through the vacuum pump pressure sensor to keep the adsorption pressure stable within the range of the target value ±0.005 MPa.

[0038] For the clamping control of metal structural parts, the clamping force can be set to 5 N, 6 N, 7 N, or 8 N; the thickness of the polyimide insulation layer is 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm. The fixture can be equipped with a piezoelectric ceramic actuator of model P-611.2S from PI company, and the clamping force sensor can be selected from the LSB200 series of Futek company. The contact surface of the jaw can be covered with Kapton-type polyimide film from DuPont company, and a grid pattern with a depth of 5 - 8 μm is formed by laser etching on the surface. The fixture is installed on a three-axis precision moving platform, the piezoelectric ceramic actuator is rigidly connected to the fixture, and the clamping force sensor is embedded at the root of the jaw.

[0039] The metal sheet is evenly adsorbed through a multi-ring aperture adsorption table, combined with the closed-loop control of the clamping force of the piezoelectric ceramic, to ensure precise positioning before welding and reduce welding offset caused by clamping deformation.

[0040] For temperature-triggered welding and vibration control, the trigger welding temperature can be selected as 80 °C, 85 °C, 90 °C, 95 °C, or 100 °C; the vibration frequency can be set to 50 Hz, 60 Hz, 80 Hz, or 100 Hz. An infrared thermometer can be selected from the FLIR A315 series, and a laser welding device can use the YLS series of fiber lasers from IPG company. The laser focusing lens group can be selected with zinc selenide material lenses, and the temperature resistance performance is > 300 °C. The infrared thermometer is installed on the side of the laser welding head, and the distance between the optical axis and the center of the welding area is 20 - 30 mm; the axis of the piezoelectric ceramic actuator is parallel to the welding direction. The time deviation between the rising edge of the vibration waveform and the leading edge of the laser pulse is < 0.1 ms through the PLC controller, and a NI company PXIe-6341 data acquisition card is used for timing synchronization.

[0041] For the shielding gas purging, the argon gas flow rate can be set to 8 L / min, 10 L / min or 12 L / min; the purging time can be selected as 20 s, 25 s or 30 s. The gas nozzle can be the MHQ series multi-hole fan-shaped nozzle of SMC Corporation, and the flow control valve uses the Bürkert 8711 type proportional valve. The annular gas nozzle is arranged around the welding area, the nozzle outlet is 10 - 15 mm away from the welding plane, and the spraying angle is 30° or 45°.

[0042] Precisely control the welding start timing through temperature feedback, improve the fluidity of the molten pool by combining with axial micro-vibration, cooperate with argon gas protection to reduce oxidation defects, and enhance the weld density.

[0043] For the two-stage cooling process, the first-stage cooling temperature can be set to 10 °C, 12 °C or 15 °C; the aerosol water droplet size of the second stage can be selected as 20 μm, 30 μm or 50 μm. The semiconductor refrigeration chip can be the 9500 series of Ferrotec Corporation, and the aerosol nozzle uses the 1 / 4J series of Spraying Systems Company. The cold end contact surface of the refrigeration chip can be nickel-plated, and the hot end is installed with copper heat dissipation fins. The first-stage cooling station is set at the head section of the linear conveyor belt, and the second-stage cooling station is located at the end section of the conveyor belt, and the distance between the two is 500 - 800 mm.

[0044] For seam detection and trimming, the grinding depth can be set to 1 μm, 2 μm or 3 μm; the detection accuracy of the white light interferometer is 0.1 μm. The white light interferometer can be the NewView 9000 series of Zygo Corporation, and the grinding device uses the Kern Micro CNC grinding machine. The detection probe is installed perpendicular to the welding plane, 10 - 15 mm away from the seam surface; the grinding head is installed at the end of the three-axis linkage robotic arm. Calibrate the white light interferometer with a stepped height standard sample block, and conduct three repeatability tests per shift, with the RSD value < 1.5%.

[0045] Reduce the residual stress by hierarchical temperature control cooling, combine with high-precision on-line detection and trimming to ensure that the surface flatness of the welded seam meets the requirements of micro-assembly, and the height difference is controlled within ±1 μm.

[0046] Operation example: When actually implementing this welding method, first prepare a vacuum adsorption table, connect it to a vacuum pump, and set the adsorption pressure to 0.06 MPa through the vacuum pump pressure control module. The surface of the vacuum adsorption table is arranged with a vacuum adsorption hole array according to the design to ensure the stable adsorption of the metal sheet. Place the small-sized metal sheet on the vacuum adsorption table, turn on the vacuum pump, and make the metal sheet be firmly adsorbed.

[0047] Next, use a fixture with a piezoelectric ceramic fine adjuster to clamp the metal structural part, monitor the clamping force in real time through a clamping force sensor, and use a piezoelectric ceramic actuator to precisely control the clamping force at 6 N. Align the optical axis of the infrared thermometer with the center of the contact area between the metal sheet and the metal structural part, set the temperature measurement range to 50 - 150 °C, and monitor the temperature of the contact area in real time.

[0048] When the infrared thermometer detects that the temperature of the contact area reaches 90 °C, start the pulsed laser welding equipment. At the same time, use the vibration control module to apply axial vibration to the metal structural part by the piezoelectric ceramic fine adjuster, set the amplitude to 3 μm, the vibration frequency to 80 Hz, the vibration waveform to a rectangular wave with a duty cycle of 40%, and the vibration phase to be synchronized with the rising edge of the pulsed laser, with the synchronization time deviation less than 1 ms.

[0049] After welding is completed, immediately start the argon protection unit, adjust the argon flow control valve to 10 L / min, and make the argon spray through the gas nozzle surrounding the welding area in a direction at an angle of 35° to the welding plane for 25 seconds to protect the welding area.

[0050] Subsequently, transfer the welded component to a two-stage cooling station. The first-stage cooling uses a semiconductor refrigeration sheet for contact cooling, set the temperature controller of the refrigerating surface to 12 °C, control the cooling rate at 0.6 °C / s, and continuously cool for 75 seconds; the second-stage cooling uses aerosol mixing cooling, set the compressed air pressure to 0.4 MPa, control the atomized water droplet diameter to 30 μm, the volume ratio of water droplets to air in the aerosol mixing medium to 1:18, the aerosol spraying direction to be at an angle of 50° to the welding plane, and the cooling time to be 35 seconds.

[0051] Finally, use a white light interferometer to detect the welding seam, set its optical probe perpendicular to the welding seam plane, and the detection accuracy is 0.1 μm. When the detected seam height difference exceeds 2 μm, trigger the numerical control grinding device, set the axial feed accuracy of the grinding head to 1 μm, control the radial rotation speed at 250 r / min, and set the grinding depth to 2 μm to trim the raised part.

[0052] In another technical solution, the parameters of the pulsed laser welding equipment are set as follows: the laser wavelength is 1064 nm, the single-pulse energy is 3 - 5 J, the pulse width is 2 - 4 ms, the pulse frequency is 10 - 15 Hz, and the spot diameter is 0.1 - 0.3 mm.

[0053] In the above technical solution, around the parameter setting of the pulsed laser welding equipment, by precisely controlling parameters such as the laser wavelength, energy, and pulse width, optimize the welding energy input and action process to improve the welding quality.

[0054] Set the laser wavelength of the pulsed laser welding equipment to 1064 nm. This wavelength has good absorptivity for most metal materials, ensuring that the laser energy effectively acts on the welding site. The single-pulse energy is controlled within 3 - 5 J, the pulse width is 2 - 4 ms, the pulse frequency is 10 - 15 Hz, and the spot diameter is 0.1 - 0.3 mm. These parameters cooperate with each other to precisely control the energy input into the welding area by each laser pulse. When welding small-sized metal sheets and metal structural parts, it can avoid problems such as excessive melting and deformation of materials caused by excessive energy, or insecure welding caused by insufficient energy, achieving a stable and reliable welding process and effectively ensuring the strength of the welded joint.

[0055] The stable parameter settings ensure that the output and distribution of laser energy remain relatively consistent during each welding process. The appropriate pulse frequency and spot diameter can make the width and depth of the weld seam uniform and stable, reducing quality defects such as uneven weld width and inconsistent penetration depth caused by energy fluctuations. Whether it is mass production or single-component welding, it can ensure the quality consistency of the welded joint, meet the strict requirements for welding quality stability in precision fields such as micro sensors, and reduce the rejection rate of products caused by welding quality differences.

[0056] The precise parameter setting helps to optimize the microstructure and macroscopic formation of the weld seam. The appropriate single-pulse energy and pulse width enable the metal material to be fully melted and fused during welding, while avoiding excessive spatter and porosity. The reasonable spot diameter can ensure that the weld seam has an appropriate width and shape, making the weld surface smooth and flat, and the transition with the base material natural, improving the appearance quality and mechanical properties of the welded joint and enhancing its reliability and durability in practical applications.

[0057] Specifically, the laser wavelength can be set to 1064 nm, which belongs to the near-infrared band and matches the absorption spectrum of metal materials. The energy adjustment is achieved by controlling the charging and discharging voltage of the capacitor inside the laser. The laser equipment that can be used is the YLS series fiber laser produced by IPG Photonics Corporation, and the wavelength output stability error is less than ±2 nm. The laser focusing lens group can select lenses made of zinc selenide material, with an antireflection coating on the surface and a transmittance ≥99.5%. The laser focusing lens group is installed at the output end of the laser welding head and is coaxially assembled with the galvanometer scanning system. The energy parameters are set through the laser control panel and are calibrated in real time using a closed-loop energy monitoring module. The monitoring sensor can select the Ophir PE50BF-DIF-C type energy meter.

[0058] The pulse width can be set to 2 ms, 3 ms, or 4 ms, and the pulse frequency can be set to 10 Hz, 12 Hz, or 15 Hz. The time parameters are adjusted through the Q-switch driving circuit of the laser, and the duty cycle error is controlled within ±5%. The pulse waveform generator can select the DG645 model of Stanford Research Systems, and its time resolution reaches 1 ns. The laser modulator can select the Model 350 electro-optic modulator of Conoptics, and the response time < 1 μs. The laser pulse timing control module is connected to the main controller through optical fiber communication and is installed in the equipment electric control cabinet. The pulse width calibration is monitored by an oscilloscope, and the Tektronix MSO64B model oscilloscope can be selected, with a sampling rate of 25 GS / s.

[0059] The spot diameter can be set to 0.1 mm, 0.2 mm, or 0.3 mm, and is achieved by replacing the focusing lens with different focal lengths or adjusting the defocus amount. The spot size measurement can use the BeamGage professional software in cooperation with a CCD beam analyzer, and the Ophir SP928 type CCD sensor can be selected. The focusing lens can select the Thorlabs LA1951-A type plano-convex lens, with a focal length of 50 mm and the material being N-BK7 optical glass. The spot positioning accuracy is adjusted by a two-dimensional translation stage, and the Newport M-462-XY type micromotion stage can be selected, with a repeat positioning accuracy of ±0.5 μm. The distance between the laser focusing lens group and the workpiece surface is real-time feedback through a laser displacement sensor, and the Keyence LK-G5000V type sensor can be selected, with a measurement error of ±1 μm. The spot concentricity calibration adopts the cross target method, and the Edmund Optics 59-869 type stainless steel calibration plate can be selected as the target.

[0060] By precisely controlling the matching of the laser wavelength with the metal absorption characteristics and combining the optimized combination of pulse energy-time parameters, precise heat input for small-sized welds is achieved; the control of the 0.1 - 0.3 mm spot diameter can reduce the width of the heat affected zone and avoid the burn-through defect of thin-walled metal sheets.

[0061] In another technical solution, the defocus amount of the pulsed laser welding is set to +0.3~+0.4 mm, the front edge rise time of the laser pulse waveform is 1.5 - 2 ms, the trailing edge fall time ≤ 0.8 ms, and the laser power drops below 10% of the peak power during the adjacent pulse interval time.

[0062] In the above technical solution, focusing on the optimization of the key parameters of pulsed laser welding, through the precise setting of parameters such as defocus amount and pulse waveform, the welding quality and stability are improved from multiple aspects to meet the high-precision welding requirements.

[0063] Set the defocus amount of pulsed laser welding at +0.3 to +0.4 mm. This range can enable the reasonable distribution of laser energy on the surface and inside of the welding material. Compared with inappropriate defocus amount settings, a suitable defocus amount can avoid problems such as too deep or too shallow weld penetration and too large or too small weld width. When welding small-sized metal sheets and metal structural parts, it can ensure that the weld has a good ratio of weld penetration to weld width, fully fuse the weld with the base material, enhance the bonding strength of the welded joint, and guarantee the reliability of the welded parts during use.

[0064] Set the front edge rise time of the pulse waveform at 1.5 - 2 ms and the trailing edge fall time ≤ 0.8 ms. This parameter setting can effectively control the input and release speed of laser energy. The reasonable setting of the front edge rise time enables the metal material to gradually absorb laser energy and avoids spatter caused by excessive instantaneous energy. The strict control of the trailing edge fall time can enable the welding molten pool to solidify quickly, reducing the generation of defects such as pores and shrinkage porosity. At the same time, the laser power drops below 10% of the peak power within the adjacent pulse interval time, which helps to reduce the range of the heat affected zone and welding deformation, making the weld surface smoother and more even, and significantly improving the forming quality to meet the strict requirements for the welding appearance in precision fields such as micro sensors.

[0065] The precise setting of the defocus amount and pulse waveform parameters makes the output and action of laser energy more stable during the welding process. When batch-welding small-sized metal parts, it can ensure that the energy input and welding effect of each welding are basically the same, effectively avoiding the problem of unstable welding quality caused by parameter fluctuations. The stable welding process not only improves production efficiency but also reduces the defective rate, making the performance of the welded joint more reliable and providing a strong guarantee for the quality consistency of products such as micro sensors.

[0066] Specifically, the defocus amount can be set at +0.3 mm, +0.35 mm, or +0.4 mm, which is achieved by adjusting the distance between the laser focusing lens group and the workpiece surface. The defocus amount adjustment mechanism can select the UPM series electric displacement stage of Micos company, with a stroke range of ±2 mm and a resolution of 0.1 μm. The laser focusing lens group can select the LA1951-A type plano-convex lens of Thorlabs company, with a material of N-BK7 optical glass, a focal length of 50 mm, and an antireflection coating of 1064 nm on the surface. The defocus amount calibration uses the feedback of a laser displacement sensor, and the Keyence company's LK-G5000V type sensor can be selected, installed on the side of the laser welding head, with the measurement direction parallel to the optical axis. Determine the optimal value through a stepped defocus test before welding, using the weld penetration fluctuation ≤ 5% as the judgment criterion, and the test material can select 0.1 mm thick 304 stainless steel sheet.

[0067] The leading edge rise time can be set to 1.5 ms, 1.8 ms, or 2 ms, and the trailing edge fall time can be set to 0.5 ms, 0.6 ms, or 0.8 ms. The waveform control is achieved through the built-in Q-switch drive circuit of the laser. The Q-switch module of the IPG YLS laser can be selected, and the rise / fall time error is ≤ ±0.1 ms. For pulse waveform monitoring, an oscilloscope of the Tektronix MSO64B type can be selected, with a sampling rate of 25 GS / s and a bandwidth of 2.5 GHz. The waveform generator can be integrated into the laser control unit, and the drive current slope is adjusted through the PID algorithm. The leading edge time calibration method is: collect the RMS difference between the actual waveform and the set waveform, and trigger the automatic compensation program when the difference exceeds 5%. The trailing edge time control is achieved by applying a reverse bias voltage, and the reverse voltage value can be set from -5 V to -10 V.

[0068] During the adjacent pulse interval, the laser power can be reduced to 8%, 5%, or 3% of the peak power, which is achieved by controlling the bias voltage of the laser power modulator. For power monitoring, an energy meter of the Ophir PE50BF-DIF-C type can be selected to measure the residual power during the pulse interval in real time. The power control module can be integrated inside the laser power supply, and the PI E-509 piezoelectric controller is used to adjust the modulator bias voltage. The residual power threshold is set to 10% of the peak power. When the detected value exceeds the threshold, the system automatically interrupts the welding and alarms. The function test method is: use a high-speed photodiode to collect the pulse sequence, measure the light intensity during the interval through an oscilloscope, the test frequency covers the full range of 10 - 15 Hz, and the qualified rate is ≥99.9% after continuously running 1000 pulses.

[0069] By controlling the positive defocus amount, the actual acting spot area is enlarged, the power density is reduced, and the burn-through of thin plates is avoided; precisely controlling the time parameters of the pulse waveform can optimize the heat input distribution and reduce the fluctuation of the heat affected zone; the power suppression technology during the interval effectively prevents the material from overheating and ensures the dimensional stability of micro-structural parts.

[0070] In another technical solution, the grinding depth of the numerically controlled grinding device is set to 1 - 3 μm, the grinding speed is 200 - 300 r / min, the argon gas flow rate is controlled at 8 - 12 L / min, and the purging time is 20 - 30 seconds.

[0071] In the above technical solution, around the setting of the parameters of the numerically controlled grinding device and the argon gas protection parameters, from two aspects of seam trimming and welding area protection, the quality and performance of the welded parts are improved.

[0072] The grinding depth of the numerically controlled grinding device is set at 1 - 3 μm, and the grinding speed is controlled at 200 - 300 r / min. This parameter range can accurately remove the raised part at the welding seam. After welding a small-sized metal sheet and a metal structural component, there may be slight unevenness on the weld surface. If not processed, it will affect the assembly accuracy and service performance of the component. By setting appropriate grinding parameters, the height difference of the seam can be strictly controlled at a low level, meeting the stringent requirements for seam flatness in precision fields such as micro sensors, ensuring the dimensional accuracy of the welded components, enabling them to precisely fit with other precision components, and improving the overall performance of the product.

[0073] The argon gas flow rate is controlled at 8 - 12 L / min, and the purging time is set at 20 - 30 seconds. Such parameter settings can quickly form a stable inert gas protection layer in the welding area after welding. The welded metal is in a high-temperature state and is extremely prone to oxidation reaction with oxygen in the air, resulting in a decrease in the mechanical properties of the welded joint. Appropriate argon gas flow rate and purging time can effectively isolate the air, prevent the oxidation reaction from occurring, avoid defects such as oxide films and pores in the welding area, ensure the corrosion resistance and strength of the welded joint, extend the service life of the welded components, and at the same time provide good basic conditions for subsequent processes such as cooling and detection, ensuring the stability and reliability of the entire welding process flow.

[0074] Specifically, the grinding depth can be set at 1 μm, 1.5 μm, 2 μm, 2.5 μm, or 3 μm, and is achieved through the axial feed servo motor control of the grinding head. The grinding speed can be set at 200 r / min, 250 r / min, or 300 r / min, and the rotational speed fluctuation is controlled within the range of ±2%. The grinding head can select a diamond grinding wheel of type PN 712345 from Kern Micro Company, with a grinding wheel particle size of 2 - 5 μm and a binder of nickel-based electroplating. The axial feed mechanism can be equipped with a grating scale of type LS487C from Heidenhain Company, with a resolution of 0.1 μm, installed on the side of the Z-axis guide rail of the grinding device. The grinding depth calibration is measured online using a laser displacement sensor, and a sensor of type LK-H020 from Keyence Company can be selected, installed 10 mm to the side of the grinding head, with the measurement direction parallel to the feed direction. The parameter setting method is: according to the height difference data detected by the white light interferometer, automatically calculate the number of grinding times, and the single grinding amount does not exceed 120% of the set depth. The functional test uses a stepped height sample block, and the surface roughness Ra ≤ 0.05 μm after grinding. The test instrument can select a contour meter of the Form Talysurf i series from Taylor Hobson Company.

[0075] The argon gas flow rate can be set to 8 L / min, 9 L / min, 10 L / min, 11 L / min or 12 L / min, and the purging time can be set to 20 s, 25 s or 30 s. The gas nozzle can be a fan-shaped nozzle of the MHQ series from SMC, with an outlet width of 3 mm and a material of SUS304 stainless steel. The flow control valve can be a type 8711 proportional valve from Bürkert, with a response time < 50 ms and a repeatability accuracy of ±0.5% F.S. The nozzle installation positions are 4 evenly distributed circumferentially around the welding area, 10 - 15 mm away from the welding plane, and the adjustable range of the spraying angle is 30° - 45°. The argon gas source can be high-purity argon of grade 6.0 from Linde Group, with a purity ≥99.9999%, and the pipeline uses 316L stainless steel double-ferrule pipe from Swagelok, with an inner diameter of 6 mm. The flow rate calibration method is: online calibration is carried out using a mass flowmeter of the GF-120 series from Brooks Instrument, and zero drift compensation is carried out once every quarter. The purging effect verification uses an oxygen content analyzer, and a type EC913 sensor from Systech Illinois can be selected. The qualified standard is that the oxygen concentration in the welding area ≤ 50 ppm.

[0076] The nano-level trimming of the weld surface is achieved by controlling the grinding depth at the 1 - 3 μm level, avoiding the structural weakening caused by excessive cutting; the cooperation of the argon gas flow rate of 8 - 12 L / min and the directional purging angle effectively isolates the air and accelerates the solidification of the molten pool, reducing the weld oxidation defect rate to less than 0.3%.

[0077] In another technical solution, the first-stage cooling of the two-stage cooling station uses a thermoelectric cooler for contact cooling, and the temperature of the cooling surface is maintained at 10 - 15 °C for continuous cooling for 60 - 90 s; the second-stage cooling uses aerosol mixing cooling, the compressed air pressure is 0.3 - 0.5 MPa, the particle size of the atomized water droplets is 20 - 50 μm, and the cooling time is 30 - 45 s.

[0078] In the above technical solution, it focuses on the two-stage cooling process after welding. Through specific cooling methods and parameter settings, the quality of the welded components is guaranteed in many aspects, and the performance of the welded parts is improved.

[0079] The first stage uses a thermoelectric cooler for contact cooling, maintaining the temperature of the cooling surface at 10 - 15°C for 60 - 90 seconds of continuous cooling; the second stage uses aerosol mixing cooling, with the compressed air pressure at 0.3 - 0.5 MPa, the atomized water droplet size at 20 - 50 μm, and the cooling time at 30 - 45 seconds. These two-stage cooling methods cooperate with each other. The thermoelectric cooler can quickly remove the heat from the surface of the welding component to achieve preliminary temperature reduction; aerosol mixing cooling further reduces the component temperature through the evaporation heat absorption of the atomized water droplets and the forced convection of the compressed air, while expanding the cooling range, enabling the entire welding component to achieve uniform cooling in a short time and avoiding local thermal stress concentration caused by uneven cooling.

[0080] The precisely controlled cooling process can effectively control the cooling rate and shrinkage process of metal components. After welding, metal components are prone to generate large thermal stresses due to sudden temperature changes. In this solution, the parameter settings of the thermoelectric cooler and aerosol mixing cooling can enable the metal components to cool down slowly and evenly, reducing the generation of internal thermal stresses. This avoids defects such as component deformation and cracks caused by excessive thermal stress, ensuring the dimensional accuracy and structural integrity of the welded components, and making their performance more stable and reliable during subsequent use.

[0081] A stable and reasonable cooling process helps to improve the microstructural organization of welded components. It avoids problems such as coarse grains and uneven organization caused by rapid cooling, enhancing the mechanical properties of metal components, such as improving the strength, toughness, and corrosion resistance of the welded joints. At the same time, the good cooling effect also provides favorable conditions for subsequent processes such as machining and assembly of welded components, ensuring the smooth progress of the entire production process and meeting the strict requirements for high performance of welded components in precision fields such as micro sensors.

[0082] Specifically, the cooling temperature of the first stage can be set at 10°C, 12°C, or 15°C, and the cooling time can be selected as 60 seconds, 75 seconds, or 90 seconds. The thermoelectric cooler can be selected from the 9500 series of Ferrotec Corporation, with the cooling surface size of 40 mm × 40 mm and the maximum temperature difference ΔT = 65°C. The contact material of the cooling surface can be nickel-plated, with a thickness of 5 - 10 μm. The heat sink at the hot end can be a copper fin structure with a fin pitch of 2 mm. The cooler is installed on the aluminum alloy base of the cooling station and is attached to the workpiece carrier plate through thermal conductive silicone grease, with the attachment pressure controlled at 0.1 - 0.3 MPa. Temperature control uses the PID algorithm. The temperature sensor can be selected as the PT100 platinum resistance of Omega Corporation and is installed at the center of the cooling surface, with a temperature measurement accuracy of ±0.1°C. The function test method is: bury the thermocouple inside a standard aluminum block (size 20 mm × 20 mm × 5 mm), record the time curve from 100°C to 15°C, and the cooling rate should reach 0.5 - 0.8°C / s.

[0083] The compressed air pressure can be set to 0.3 MPa, 0.4 MPa or 0.5 MPa. The atomized water droplet size can be selected as 20 μm, 30 μm or 50 μm. The cooling time can be set to 30 s, 37.5 s or 45 s. The atomizing nozzle can be selected from the 1 / 4J series of Spraying Systems Company, with the internal mixing cavity made of 316L stainless steel and the aperture of 0.5 mm. The compressed air source can be selected from the GA series air compressors of Atlas Copco Company, equipped with an AF30M-06 type filter of SMC Company, and the filtration accuracy is 0.3 μm. The aerosol nozzle is installed 200 mm above the cooling station, and the adjustable range of the spraying angle is 45° - 60°, and it is fixed to the linear slide rail through a bracket. The control of the water droplet size adopts on-line monitoring by laser diffraction method, and a Mastersizer 3000 type particle size analyzer of Malvern Company can be selected, with a sampling frequency of 10 Hz. The aerosol mixing ratio is adjusted by a mass flow meter, and the volume ratio of air to water can be set to 1:15, 1:18 or 1:20. The water supply system can be equipped with a Cole-Parmer EW-07553-65 type micro metering pump, and the flow accuracy is ±1%F.S.

[0084] Rapid temperature drop is achieved through contact cooling by the first-stage semiconductor refrigeration sheet to inhibit the grain coarsening in the welding area; the second-stage aerosol mixing cooling can evenly distribute the thermal stress while ensuring the cooling efficiency, so that the overall deformation of the workpiece is controlled within 0.05 mm / m, and the fluctuation range of the microhardness is ≤5 HV0.2.

[0085] In another technical solution, the cooling rate of the semiconductor refrigeration sheet in the first-stage cooling is controlled at 0.5 - 0.8 °C / s; in the aerosol mixing medium of the second-stage cooling, the volume ratio of water droplets to air is 1:15 - 1:20, and the aerosol spraying direction forms an angle of 45 - 60° with the welding plane.

[0086] In the above technical solution, the key parameters of the two-stage cooling process are further refined. By accurately regulating the cooling rate of the semiconductor refrigeration sheet and the medium ratio and spraying angle of the aerosol mixing cooling, the cooling effect is significantly improved and the performance of the welded components is enhanced.

[0087] Control the cooling rate of the thermoelectric cooler in the first-stage cooling within 0.5 - 0.8 °C / s to avoid excessive thermal stress inside the metal components caused by too fast cooling rate, or affecting the production efficiency due to too slow cooling rate. This rate can make the temperature of the metal components drop steadily. Combined with the cooling surface temperature of 10 - 15 °C, preliminary uniform cooling is achieved. In the second-stage cooling, the volume ratio of water droplets to air in the aerosol mixture medium is set to 1:15 - 1:20. Combined with the aerosol spraying direction of 45 - 60°, the atomized water droplets can more evenly cover the surface of the welding assembly. A large amount of heat is carried away during the evaporation of the water droplets, and the air flow accelerates the heat diffusion, ensuring that similar cooling effects can be obtained at different parts of the assembly, further improving the cooling uniformity, and effectively avoiding deformation caused by large local temperature differences.

[0088] The precise cooling rate and uniform cooling process can more effectively control the shrinkage deformation of metal components during the cooling stage. The stable cooling rate of the thermoelectric cooler enables the slow reorganization of the metal lattice and reduces the accumulation of internal stress; the aerosol mixed cooling continuously and evenly removes heat through the optimized medium ratio and spraying angle, avoiding heat stress concentration caused by uneven cooling. Thus, the risk of cracks in the welded components due to excessive thermal stress is significantly reduced, ensuring the dimensional accuracy of the components, making their performance more stable and reliable during subsequent use, and meeting the strict requirements for component quality in precision fields such as micro sensors.

[0089] The coordinated optimization of the parameters of the thermoelectric cooler and the aerosol mixed cooling realizes the transition from rapid preliminary cooling to fine and uniform cooling. The reasonable cooling rate and medium ratio improve the cooling quality while ensuring the cooling efficiency. The stable cooling process helps to improve the microstructure of the welded components, refine the grains, and enhance the mechanical properties of the metal, such as increasing the strength, toughness, and corrosion resistance of the welded joints. At the same time, the good cooling effect also provides favorable conditions for subsequent processes such as machining and assembly of the welded components, ensuring the smooth progress of the entire production process, and improving the product yield and production efficiency.

[0090] Specifically, the first-stage cooling rate can be set to 0.5℃ / s, 0.6℃ / s, 0.7℃ / s or 0.8℃ / s, which is achieved by adjusting the input current of the thermoelectric cooler. The thermoelectric cooler can be selected from the 9500 series of Ferrotec Corporation, with a maximum refrigeration power of 120W and a working voltage of 12VDC. The temperature sensor can be an Omega PT100 platinum resistance, installed at the center of the cooling surface, with the contact surface with the workpiece carrier plated with nickel and a thickness of 5 - 10μm. The thermoelectric cooler is installed at the bottom of the aluminum alloy carrier and is bonded to the carrier through thermal conductive grease (Dow Corning TC-5026 type can be selected), and the contact pressure is controlled at 0.2 - 0.4MPa. The cooling rate control adopts the PID algorithm, and the controller can be an Omron E5CN-H type temperature controller with a sampling period of 0.1 second. The functional test method is as follows: Heat a 304 stainless steel sheet with a thickness of 0.5mm to 150℃ and then start cooling. Use a K-type thermocouple to record the temperature curve and calculate the average cooling rate. The test is repeated 10 times, and the allowable fluctuation range is ±0.05℃ / s.

[0091] The volume ratio of water to air in the aerosol mixing medium can be set to 1:15, 1:18 or 1:20. The water supply system can be equipped with a Cole-Parmer EW-07553-65 type micro metering pump, with a flow range of 0.1 - 50mL / min and an accuracy of ±1%F.S. The compressed air source can be an Atlas Copco GA11 type air compressor, with an adjustable output pressure of 0 - 1MPa. The mixing ratio control is achieved through a mass flow meter. The air flow meter can be selected from the GF-120 series of Brooks Instrument, and the water flow meter can be a Key Instruments R-2500 type rotameter. The mixing chamber can be a Swagelok SS-4F-W body, made of 316L stainless steel, with spiral guide vanes inside to enhance the mixing uniformity. The method for verifying the mixing uniformity is as follows: Use a high-speed camera (Photron FASTCAM Mini AX200 type can be selected) to photograph the aerosol flow field and count the uniformity of the water droplet distribution. It is required that the difference in water droplet density within a 50mm diameter area is ≤15%.

[0092] The aerosol spray angle can be set to 45°, 50°, 55°, or 60°, which is achieved through an adjustable-angle bracket. The bracket can be selected as the HBLFSN type aluminum profile bracket from Misumi, with an angle scale resolution of 1°. The nozzle can be selected as the 1 / 8JAU type fan-shaped nozzle from Spraying Systems, made of polytetrafluoroethylene, with a temperature resistance of 250°C. The nozzle is installed at a height of 200 - 300 mm above the cooling station, and the horizontal position adjustment is achieved through a linear slide rail (the SR15 type from THK can be selected). The calibration of the spray coverage range uses the thermal paper test method. Place the Thermo Label G type thermal paper from Fujifilm on the welding plane, and detect the color difference uniformity after spraying. The angle adjustment mechanism is equipped with a digital display inclinometer (the TA-10 type from Sauter can be selected), with a measurement accuracy of ±0.1°. The requirements for spray coverage verification are that the aerosol coverage area in the weld area is ≥95%, and the temperature gradient in the edge area is ≤3°C / mm.

[0093] Precisely control the grain refinement rate in the initial cooling stage at 0.5 - 0.8°C / s to homogenize the microstructure in the weld area; a 1:15 - 1:20 aerosol ratio balances the evaporation heat absorption and gas convection effects, reducing cooling deformation; a 45 - 60° spray angle optimizes the aerosol coverage uniformity, controlling the overall cooling temperature difference of the workpiece within ±5°C, and the flatness deviation ≤0.02 mm.

[0094] In another technical solution, the vibration waveform of the piezoelectric ceramic trimmer is a rectangular wave with a duty cycle of 30 - 50%, and the vibration phase is synchronized with the rising edge of the pulsed laser, with a synchronization time deviation of less than 1 ms.

[0095] In the above technical solution, by precisely setting the synchronization between the vibration waveform of the piezoelectric ceramic trimmer and the rising edge of the pulsed laser, the energy and material interaction during the welding process are optimized, thereby improving the welding quality and stability.

[0096] Set the vibration waveform of the piezoelectric ceramic trimmer as a rectangular wave with a duty cycle of 30 - 50%, and synchronize the vibration phase with the rising edge of the pulsed laser, with a synchronization time deviation of less than 1 ms. At the moment when the laser acts on the metal component, the vibration can prompt the metal in the molten pool to flow violently, breaking the non-uniform distribution of temperature and composition in the molten pool. This flow helps the gas to escape, reducing the formation of pores; at the same time, it enables the impurities to float up and be discharged fully, reducing the generation probability of inclusion defects. By improving the metallurgical reaction conditions in the molten pool, refining the weld grains, and making the weld microstructure more dense and uniform, the mechanical properties such as the strength and toughness of the welded joint are significantly improved.

[0097] Precise vibration and laser synchronization control make the energy input and material response in the welding process more regular. During each laser pulse action cycle, the vibration can participate in the welding process with a fixed phase, avoiding the energy distribution disorder and welding instability caused by the out-of-sync of vibration and laser. Whether it is batch welding or complex structure welding, it can ensure the consistency of each welding process, reduce the welding quality difference caused by process fluctuations, improve the stability and reliability of welding production, and reduce the defective rate.

[0098] The optimized synergistic effect of vibration and laser forms a stronger bonding interface between the weld and the base metal. Vibration promotes the element diffusion and metallurgical bonding between the molten pool and the base metal, reducing the stress concentration phenomenon at the welding joint. At the same time, the good microstructure and stable welding process effectively reduce the failure risks such as fatigue cracks and brittle fractures that occur in the welding joint during use, improve the reliability of the welding joint under long-term use and complex working conditions, and meet the strict requirements for high reliability of welded components in precision fields such as micro sensors.

[0099] Specifically, the duty cycle of the vibration waveform can be set to 30%, 35%, 40%, 45% or 50%, and the vibration frequency can be set to 50Hz, 60Hz, 80Hz or 100Hz. The piezoelectric ceramic actuator can be selected as the P-611.2S type of PI company, with a maximum displacement stroke of 15μm and a thrust of 200N. The waveform generator can be integrated into the driver controller and adopt a rectangular wave output mode, with a rise / fall time ≤ 1μs. The drive signal is transmitted through a BNC interface, and the cable can be selected as the Belden 8259 type double-shielded coaxial cable with a length not exceeding 1.5 meters. The vibration waveform monitoring can be selected as the MSO64B type oscilloscope of Tektronix company, with a sampling rate of 25GS / s and a bandwidth of 2.5GHz. The duty cycle calibration method is: collect 100 consecutive waveform cycles, and the deviation between the calculated average value and the set value should be ≤ ±1%. The function test uses a laser displacement sensor (the Keyence LK-G5000V type can be selected) to measure the amplitude in real time, and the amplitude fluctuation range at a frequency of 50Hz should be controlled within ±0.2μm, and the test is repeated 10 times and the average value is taken.

[0100] The synchronous time deviation between the vibration phase and the rising edge of the laser pulse can be set to 0.05 ms, 0.08 ms or 0.1 ms. The synchronous controller can select the PXIe-6341 data acquisition card of National Instruments, with a time resolution of 1 ns. The trigger signal is transmitted through an optical fiber. The optical fiber module can select the HFBR-1521 type of Hirose, and the transmission delay < 5 ns. The phase synchronization calibration method is: input the laser pulse signal and the vibration waveform signal into the oscilloscope at the same time, and measure the time difference with the cursor. When the deviation exceeds 0.1 ms, automatically adjust the trigger delay parameter of the piezoelectric ceramic driver, and the adjustment step is 0.01 ms. The laser pulse signal acquisition can select the DET10A photodiode of Thorlabs, with a response time of 1 ns. The synchronous stability test method is: continuously run for 1 hour, record the time deviation every 10 seconds, and the standard deviation is required to be ≤ 0.02 ms. The test data is statistically analyzed through LabVIEW software, and the R² value of the fitting curve ≥ 0.99.

[0101] Optimize the molten pool disturbance frequency through a rectangular wave vibration with a duty cycle of 30 - 50%, so that the uniformity of the weld grain size is increased by 20%; the 0.1 ms-level phase synchronization control realizes the precise matching of the vibration energy and the laser heat input, reduces the fluctuation range of the width of the weld heat affected zone to ±5 μm, and reduces the standard deviation of the tensile strength to ≤ 15 MPa.

[0102] In another technical solution, the vacuum adsorption hole array is divided into three circles from the inside to the outside. The inner circle has a hole diameter of 0.3 - 0.5 mm, the middle circle has a hole diameter of 0.2 - 0.3 mm, and the outer circle has a hole diameter of 0.1 - 0.2 mm; the adjacent hole circle spacings are 2 mm, 1.5 mm and 1 mm respectively, and the included angle between the center connection lines of the adjacent layer holes is 22.5°.

[0103] In the above technical solution, through the special design of the vacuum adsorption hole array, optimize from aspects such as the adsorption force distribution and stability, provide a reliable guarantee for the fixation of small-sized metal sheets, and thereby improve the overall quality of welding.

[0104] The vacuum adsorption hole array adopts a design with the inner, middle, and outer three circles of pore diameters decreasing in sequence. The inner circle pore diameter is 0.3 - 0.5 mm, the middle circle pore diameter is 0.2 - 0.3 mm, and the outer circle pore diameter is 0.1 - 0.2 mm. This pore size distribution enables the vacuum adsorption table to form an adsorption force gradient that gradually decreases from the center to the edge on the surface of the metal sheet during operation. At the same time, the adjacent hole circle spacings are 2 mm, 1.5 mm, and 1 mm respectively, and the layout with the included angle between the center connection lines of adjacent layer holes being 22.5° ensures the uniform distribution of the adsorption force on the surface of the metal sheet. Compared with the conventional single pore size or disordered distribution of adsorption hole designs, this array can make the metal sheet receive a more balanced adsorption force during the welding process, avoiding the warping or displacement of the metal sheet caused by insufficient local adsorption force, ensuring that the metal sheet always maintains a stable position during welding, and laying a foundation for high-precision welding.

[0105] The reasonable design of pore size, spacing, and hole position angle makes the sealing effect between the vacuum adsorption table and the metal sheet better. Under the set vacuum adsorption pressure of 0.05 - 0.08 MPa, it can effectively prevent air leakage and ensure the stable output of the adsorption force. Even during the welding process, due to the change in the surface temperature of the metal sheet caused by the input of laser energy, resulting in minor thermal deformation, this adsorption hole array can still firmly fix the metal sheet on the adsorption table with its stable adsorption performance. This highly stable adsorption effect reduces problems such as welding deviation and false soldering caused by the movement of the metal sheet, significantly improving the consistency and reliability of the welding quality, and is particularly suitable for the welding scenarios of small-sized metal sheets and metal structural parts with extremely high precision requirements.

[0106] Since the metal sheet can be stably adsorbed during the welding process without additional auxiliary fixing measures, the preparation process before welding is simplified. At the same time, the stable position fixation enables the laser welding equipment to process the welding part more precisely, reducing the repeated welding or correction work caused by position deviation. This not only improves the precision of a single welded component but also speeds up the overall production rhythm and enhances production efficiency. In addition, the stable adsorption effect reduces the scrap rate and the waste of raw materials, enhancing the comprehensive benefits of the welding process from multiple aspects and meeting the requirements of high-efficiency and high-precision welding in precision manufacturing fields such as micro sensors.

[0107] Specifically, the inner ring aperture can be set to 0.3 mm, 0.4 mm or 0.5 mm, the middle ring aperture can be set to 0.2 mm, 0.25 mm or 0.3 mm, and the outer ring aperture can be set to 0.1 mm, 0.15 mm or 0.2 mm. The hole array of the vacuum adsorption table can be processed by a Sodick AP250L CNC electric discharge machining machine with an electrode wire diameter of 0.1 mm and a machining accuracy of ±0.005 mm. The matrix material of the adsorption table can be selected as 6061-T6 aluminum alloy, and the surface is subjected to hard anodic oxidation treatment with an oxidation layer thickness of 10 - 15 μm. The inner wall of the hole can be coated with a Teflon coating (Chemours Teflon® AF 2400 type can be selected) with a thickness of 2 - 5 μm and a friction coefficient ≤0.1. The hole array layout design is generated by CAD software. The number of holes in the inner ring can be set to 8, the middle ring to 16, and the outer ring to 32, evenly distributed on circumferences with diameters of 10 mm, 14 mm, and 18 mm respectively. After the hole positions are processed, a flow rate test is required, and the difference in vacuum adsorption force between each ring should be ≤5%.

[0108] The distance between adjacent hole rings can be set to 2 mm from the inner ring to the middle ring, 1.5 mm from the middle ring to the outer ring, and 1 mm from the outer ring to the edge. The distance control is detected by a Mitutoyo CMM coordinate measuring machine of Mitutoyo Corporation with a measuring accuracy of ±1 μm. The substrate processing of the adsorption table can be selected as a Mazak VTC-800C CNC milling machine equipped with an HSK-A63 tool holder and a YG8 carbide drill bit. The method for setting the distance parameters is: optimize the adsorption force distribution through finite element analysis, and use the surface deformation of a 0.1 mm thick stainless steel sheet adsorbed ≤0.01 mm as the judgment standard. After processing, a laser interferometer (Zygo GPI XP type can be selected) is used to detect the hole position deviation, and the allowable error is ±0.02 mm. The functional test method is: evenly place 10 pressure sensors (TE Model 31 type can be selected) on the surface of the adsorption table. When a vacuum pressure of 0.08 MPa is applied, the pressure fluctuation in each area should be ≤±0.005 MPa.

[0109] The angle between the center connection lines of adjacent layer hole positions can be set to 22.5°, which is achieved by indexing plate processing. The indexing device can be selected as a Tsudakoma KRP-08 CNC indexing plate with an angle resolution of 0.001°. The hole position angle calibration is carried out by an optical projector (Nikon V-12B type can be selected) with a magnification of 50X and a measurement error of ±0.1°. The hole position angle layout design follows the Archimedes spiral distribution law, and the angle error of the air flow channel between adjacent hole positions is controlled within ±0.5°. After processing, it is verified by the air flow rate test method: introduce 0.1 MPa compressed air into the adsorption holes, and use a hot wire anemometer (Kanomax ClimaMaster 6542 type can be selected) to measure the outlet air speed of each hole, and the deviation should be ≤±5%.

[0110] Optimize the vacuum adsorption force gradient distribution through the design of segmented and tapered apertures to avoid warping at the edges of thin workpieces; the decreasing hole circle spacing of 2 - 1 mm matches the law of airflow attenuation, ensuring that the workpiece fitting degree is ≥ 99.5% under an adsorption pressure of 0.05 - 0.08 MPa; the arrangement with a 22.5° angle eliminates the adsorption dead zone, and the workpiece positioning repeat accuracy reaches ±0.005 mm.

[0111] In another technical solution, the clamping surface of the fixture is covered with a polyimide insulating layer. The thickness of the polyimide insulating layer is 0.2 - 0.5 mm, and the surface is laser-etched to form a grid-like pattern with a pattern depth of 5 - 8 μm and a grid density of 20 - 30 lines / mm; at 25°C and a normal load of 5 N, the static friction coefficient between the insulating layer and the metal structural part is controlled within the range of 0.4 - 0.6, and the volume resistivity is ≥ 1×10 14 Ω·cm.

[0112] In the above technical solution, by defining the material properties, structural design, and performance parameters of the polyimide insulating layer on the clamping surface of the fixture, the reliability and applicability of the fixture during the welding process are effectively improved.

[0113] The thickness of the polyimide insulating layer is controlled within 0.2 - 0.5 mm, and the volume resistivity is ≥ 1×10 14 Ω·cm at 200°C. This high insulation performance can effectively isolate the current generated during the welding process, prevent the current from being conducted to the metal structural part through the fixture, and avoid welding abnormalities caused by short circuits, ensuring the safety of the welding equipment and operators. At the same time, the stable insulation performance will not fail due to temperature changes during the welding process, ensuring the safe and stable progress of the entire welding process.

[0114] The surface of the insulating layer is laser-etched to form a grid-like pattern with a pattern depth of 5 - 8 μm and a grid density of 20 - 30 lines / mm, and the static friction coefficient with the metal structural part is controlled within the range of 0.4 - 0.6. This special surface structure design increases the friction force between the fixture and the metal structural part, making the metal structural part not easy to slide or shift during the welding process. Even under complex working conditions such as vibration and high temperature in pulsed laser welding, it can maintain a stable clamping state, ensure the relative position accuracy between the metal structural part and the metal sheet, provide reliable guarantee for high-quality welding, reduce welding defects caused by component displacement, and improve the welding yield.

[0115] Polyimide material has good high temperature resistance, wear resistance and chemical stability, and can withstand high temperature, mechanical friction and chemical effects of protective gases such as argon during welding. The grid-like texture on its surface increases friction while dispersing the clamping force, reducing damage to the surface of metal structural parts. In addition, the stable performance parameters enable the clamp to maintain good clamping effect and insulation performance during long-term use, without the need for frequent replacement, reducing production costs. It is also suitable for metal structural parts of various materials and shapes, broadening the application range of the clamp and improving the versatility and flexibility of the welding process.

[0116] Specifically, the thickness of the polyimide insulation layer can be set to 0.2mm, 0.3mm, 0.4mm or 0.5mm. The material can be DuPont's Kapton® HN film, with a long-term use temperature range of -269°C to 400°C. The insulation layer is bonded to the contact surface of the clamp jaws through an epoxy adhesive (3M DP460 can be used), with a bonding pressure of 0.1-0.3MPa and a curing temperature of 80°C for 2 hours. The base material of the jaws can be 7075-T6 aluminum alloy, and the surface is sandblasted (Ra=3.2μm) to enhance the bonding strength. After bonding, the edge of the insulation layer is trimmed by laser cutting. The cutting equipment can be Trumpf's TruMark 5000 laser processing machine with a power of 20W and a wavelength of 355nm. The functional test method is: clamp the insulation layer jaws with a diameter of 1mm, apply a clamping force of 8N and measure the contact resistance. The resistance value is required to be ≥1×10 10 Ω, the test instrument can be Keysight's B2987A high resistance meter.

[0117] The grid texture depth can be set to 5μm, 6μm, 7μm or 8μm, and the density can be set to 20 lines / mm, 25 lines / mm or 30 lines / mm. The laser etching equipment can be selected from TRUMPF's TruMark 5000, which uses a parameter combination of pulse width 10ns, frequency 50kHz, and single pulse energy 0.1mJ. The etching path generates a cross-grid pattern through CAD software, with a line width of 10-15μm and an etching speed of 200-300mm / s. The surface roughness detection after etching can use Taylor Hobson's Talysurf CCILite non-contact profiler, with a measurement area of 1mm×1mm and an Ra value controlled at 0.8-1.2μm. The method for verifying the uniformity of the texture is to measure the grid node spacing at 10 different locations, and the standard deviation must be ≤0.5 lines / mm. The orthogonal test method was used in the etching parameter optimization experiment. The 0.3mm thick Kapton film was used as the object to examine the effects of laser power, scanning speed, and repetition frequency on the engraving depth and edge quality. The power density threshold of 0.8-1.2J / cm² was finally determined.

[0118] The static friction coefficient can be controlled at 0.4, 0.5 or 0.6, which is achieved by adjusting the combination of the grid pattern depth and density. For the friction coefficient test, a UMT TriboLab friction testing machine from Bruker can be used. The counter-piece is a SUS304 stainless steel plane, with a load of 5N and a sliding speed of 1mm / s. The test is repeated 5 times and the average value is taken. For the volume resistivity test, it can be carried out with reference to ASTM D257 standard. In a 200°C constant temperature oven (such as the Heratherm type from ThermoScientific), the three-electrode method is used for measurement. A voltage of 500V is applied, and the stabilization time is 30 minutes. The test sample is a 20mm×20mm insulation layer slice, and the resistivity is required to be ≥1×10 14 Ω·cm. The verification method for the high-temperature stability of the insulation layer is as follows: after continuously working for 48 hours at 200°C, the change rate of the surface pattern morphology is detected to be ≤3%, and the attenuation of the volume resistivity is ≤1 order of magnitude.

[0119] The current isolation during the clamping process is achieved through a 0.2 - 0.5mm polyimide insulation layer to avoid the interference of stray current during welding; the grid pattern with a depth of 5 - 8μm keeps the clamping static friction coefficient stable within the range of 0.4 - 0.6, and the workpiece slip is ≤0.005mm; the volume resistivity remains ≥1×10 14 Ω·cm at high temperature, ensuring no risk of electric leakage during the welding process, and the yield rate is increased to over 99.8%.

[0120] Provide a welding device for small-sized metal sheets and metal structural parts in the field of micro sensors, including: A vacuum adsorption table, on the surface of which there is an array of vacuum adsorption holes. The vacuum adsorption table is connected to a vacuum pump, and the adsorption pressure is set to 0.05 - 0.08MPa by the vacuum pump pressure control module; A piezoelectric ceramic fine-tuning fixture, which includes jaws for clamping the metal structural part, a polyimide insulation layer covering the contact surface of the jaws, a piezoelectric ceramic driver, and a clamping force sensor. The clamping force sensor is electrically connected to the piezoelectric ceramic driver to control the clamping force to be 5 - 8N; An infrared temperature measurement module, which includes an infrared thermometer with a focused spot diameter of 0.5 - 0.8mm. The optical axis of the infrared thermometer is aligned with the center of the welding area, and the temperature measurement range is 50 - 150°C; A pulsed laser welding device, at the optical path outlet of which there is a laser focusing lens group with a wavelength of 1064nm. The focal length adjustment mechanism of the laser focusing lens group is coaxially arranged with the vibration direction of the piezoelectric ceramic fine-tuning fixture; A vibration control module, which includes a vibration generator and a frequency controller connected to the piezoelectric ceramic fine-tuning fixture. The vibration generator outputs an axial vibration with an amplitude of 2 - 5μm and a vibration frequency of 50 - 100Hz; An argon protection unit, which includes a gas nozzle surrounding the welding area, an argon flow control valve, and an argon gas source. The injection direction of the gas nozzle forms an angle of 30 - 45° with the welding plane; A two-stage cooling station, which includes a first-stage semiconductor refrigeration sheet contact cooling module and a second-stage aerosol mixing cooling module. The temperature controller of the refrigerating surface of the first-stage cooling module is set to 10 - 15°C. The second-stage cooling module includes a compressed air source, an atomizing nozzle, and a water droplet size controller. The compressed air pressure is set to 0.3 - 0.5 MPa, and the atomized water droplet size is controlled to be 20 - 50 μm; An inspection and trimming unit, which includes a white light interferometer and a numerically controlled grinding device. The optical probe of the white light interferometer is perpendicularly arranged to the welding seam plane, and the detection accuracy is 0.1 μm. The axial feed accuracy of the grinding head of the numerically controlled grinding device is 1 μm, and the radial rotation speed is controlled to be 200 - 300 r / min; A central control module, which is electrically connected to a vacuum pump pressure control module, a clamping force sensor, an infrared thermometer, a pulsed laser welding device, a vibration control module, an argon flow control valve, a two-stage cooling station, and an inspection and trimming unit respectively. The central control module triggers pulsed laser welding according to the signal of the infrared thermometer, and controls the start and stop of the numerically controlled grinding device according to the detection result of the white light interferometer.

[0121] In the above technical solution, through the innovative design and coordinated control of each module of the welding device, many problems in the welding of small-sized metal sheets and metal structural parts are effectively solved, and high-precision and high-quality welding operations are achieved.

[0122] The vacuum adsorption table is equipped with a vacuum adsorption hole array with specific parameters, and with an adsorption pressure of 0.05 - 0.08 MPa, it can stably and uniformly adsorb and fix small-sized metal sheets, avoiding deformation or displacement problems caused by traditional mechanical clamping methods. The piezoelectric ceramic fine-tuning fixture, relying on the linkage of the clamping force sensor and the piezoelectric ceramic driver, precisely controls the clamping force within 5 - 8 N. At the same time, the polyimide insulating layer and its special surface treatment provide appropriate friction while ensuring insulation, realizing stable clamping and fine positioning of metal structural parts, ensuring the precise position of welding parts, and laying a foundation for high-quality welding.

[0123] The infrared temperature measurement module uses an infrared thermometer with a focused spot diameter of 0.5 - 0.8 mm to monitor the temperature of the welding area in real time and accurately. The temperature measurement range covers the temperature range required for welding, ensuring that the pulsed laser welding equipment is started at the optimal temperature. The pulsed laser welding equipment works in coordination with the vibration control module. The focal length adjustment mechanism of the laser focusing lens group is arranged coaxially with the vibration direction, enabling the laser energy and the axial vibration to act precisely on the welding part, optimizing the weld formation and reducing welding defects. At the same time, the argon protection unit sprays argon at a specific angle, effectively isolating the air, preventing oxidation of the welding area, and ensuring stable welding quality.

[0124] As Figure 2 shown, the semiconductor refrigeration sheet contact cooling module and the aerosol mixing cooling module of the two-stage cooling station work in coordination with precisely set parameters such as temperature and pressure to achieve rapid and uniform cooling of the welding assembly, significantly reducing the internal thermal stress of metal components and avoiding deformation and crack generation. The control system of the two-stage cooling station includes a human-machine interface, a PLC controller, a semiconductor temperature control module, an aerosol timing controller, a conveyor belt servo drive, a PT100 temperature feedback, and a pressure sensor feedback. In the detection and trimming unit, the white light interferometer detects the flatness of the welding seam with a high precision of 0.1 μm. The numerical control grinding device trims the unqualified parts precisely with an axial feed accuracy of 1 μm and a precisely controlled grinding speed, ensuring that the welding seam meets the strict requirements of precision fields such as micro sensors.

[0125] The central control module conducts unified coordination and intelligent control of each functional module, automatically triggering corresponding operations according to real-time monitoring data, such as starting welding based on the signal of the infrared thermometer and controlling trimming according to the detection result of the white light interferometer, realizing the full automation and intelligence of the welding process. This highly integrated design not only greatly improves the welding efficiency, reduces the errors caused by manual intervention, but also ensures the close cooperation and coordinated operation of each link, effectively improving the consistency and stability of welding quality, and meeting the urgent needs of modern precision manufacturing for high-efficiency and precise welding equipment.

[0126] Specifically, the adsorption pressure of the vacuum adsorption table can be set to 0.05 MPa, 0.06 MPa, 0.07 MPa or 0.08 MPa. The vacuum pump can be the R5 RA 0023 C type of Busch company. The inner diameter of the adsorption hole array is 0.3 - 0.5 mm, and the outer diameter is 0.1 - 0.2 mm. The substrate of the adsorption table can be made of 6061 aluminum alloy, with a surface hard anodizing treatment and an oxide layer thickness of 10 - 15 μm. The clamping force of the piezoelectric ceramic fixture can be set to 5 N, 6 N, 7 N or 8 N. The actuator can be the P-611.2S type of PI company. The clamping force sensor can be the LSB200 series of Futek company, with a measuring range of 0 - 10 N. The adsorption table is installed on the horizontal reference plane of the welding workbench and connected to the vacuum pump through a vacuum pipeline. The piezoelectric ceramic fixture is fixed on a three-axis precision moving platform (the EG series of HIWIN company can be selected). The jaws are covered with a 0.3 mm thick polyimide insulating layer, and the surface is laser-etched with grid patterns. The functional test method is as follows: when adsorbing a 0.1 mm thick stainless steel sheet, the edge warping amount ≤ 0.005 mm; the clamping force fluctuation is controlled within the range of ±0.2 N.

[0127] The infrared thermometer can be the A315 type of FLIR company, with a temperature measurement range of 50 - 150 °C, a focused spot diameter of 0.5 - 0.8 mm, and is installed 20 - 30 mm to the side of the laser welding head. The pulsed laser welding equipment can be the YLS series of fiber lasers of IPG company, with a wavelength of 1064 nm, a single pulse energy of 3 - 5 J, and a spot diameter of 0.1 - 0.3 mm. The amplitude of the vibration control module can be set to 2 μm, 3 μm, 4 μm or 5 μm, the frequency is 50 - 100 Hz, the vibration generator can be the E-509 type of PI company, and the synchronous deviation < 0.1 ms. The laser focusing lens group can be made of zinc selenide material lenses, with a focal length of 50 mm, and is installed coaxially with the vibration direction. The welding parameter setting method is as follows: dynamically adjust the pulse frequency according to the infrared temperature measurement signal, and reduce the frequency to 10 Hz when the temperature exceeds 100 °C. The vibration waveform uses a rectangular wave with a duty cycle of 30 - 50%, and the synchronous control with the laser pulse is achieved through the PXIe-6341 data acquisition card of NI company.

[0128] The gas flow rate of the argon protection unit can be set to 8 L / min, 10 L / min or 12 L / min. The nozzle can be selected from the MHQ series of SMC Corporation, with a spraying angle of 30 - 45°, and the argon purity ≥ 99.999%. In the two-stage cooling station, the first-stage thermoelectric cooler can be selected from the 9500 series of Ferrotec Corporation, with the refrigerating surface temperature of 10 - 15 °C. The compressed air pressure for the second-stage aerosol mixing cooling is 0.3 - 0.5 MPa, and the water droplet diameter is 20 - 50 μm. The white light interferometer of the detection and trimming unit can be selected from the NewView 9000 type of Zygo Corporation, with a detection accuracy of 0.1 nm. The numerical control grinding device can be selected from the grinding machine of Kern Micro Corporation, with a grinding depth of 1 - 3 μm. The argon nozzles are arranged around the welding area, 10 - 15 mm away from the workpiece surface. The first-stage cooling station is located at the head section of the conveyor belt, with a contact time of the cooler of 60 - 90 seconds; the second-stage cooling station is located at the tail section, with an aerosol spraying time of 30 - 45 seconds. The probe of the white light interferometer is installed perpendicular to the welding plane. When the detected height difference > 2 μm, the grinding program is triggered, and the feeding accuracy of the grinding head is 1 μm.

[0129] The central control module can be selected from the CX2040 type embedded controller of Beckhoff Corporation, integrating EtherCAT bus communication and realizing real-time data interaction with each subsystem. The control program uses the TwinCAT 3 software platform to compile a welding process recipe library, storing ≥ 100 groups of parameter combinations. The human-machine interface can be selected from the GP-4501TW type touch screen of Pro-face Corporation, with a resolution of 1024×768, and 20 process parameters such as temperature, pressure, vibration frequency, etc. are displayed in real time. The controller is installed in the equipment's electrical control cabinet and is connected to the laser and sensors through optical fibers, with a signal delay < 1 ms. The function verification method is: simulate the welding process 500 times, and statistically analyze the consistency of the response time of each subsystem, with a standard deviation ≤ 0.5 ms. The data storage uses the SQLite database to record the welding parameters and detection results of each workpiece, supporting the traceability of the production data of the last 1000 pieces.

[0130] The micron-level positioning accuracy is achieved through the cooperation of vacuum adsorption and piezoelectric fixtures, with the workpiece clamping repeatability ≤ ±0.005 mm; the closed-loop control of infrared temperature measurement and laser parameters reduces the thermal input fluctuation ≤ ±3%, and the weld penetration consistency is improved by 15%; the two-stage cooling and on-line trimming reduce the residual stress to below 120 MPa, and the surface roughness Ra ≤ 0.1 μm; the central control module realizes the coordination of multiple parameters, controls the production beat within 45 seconds per piece, and the good product rate ≥ 99.5%.

[0131] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention. For those skilled in the art, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the illustrated examples described herein.

Claims

1. A welding method for small-sized metal sheets and metal structural parts, characterized in that, It includes the following steps: Fix the metal sheet by a vacuum adsorption table, and set the vacuum adsorption pressure to 0.05 - 0.08 MPa; Clamp the metal structural part by a fixture with a piezoelectric ceramic fine adjuster, and control the clamping force within the range of 5 - 8 N; Use an infrared thermometer to monitor the temperature of the contact area between the metal sheet and the metal structural part in real time. When the temperature of the contact area reaches 80 - 100 °C, start the pulsed laser welding equipment; Apply axial vibration to the metal structural part through the piezoelectric ceramic fine adjuster, with an amplitude of 2 - 5 μm and a vibration frequency of 50 - 100 Hz; After welding is completed, purge the welding area with argon as the shielding gas; Transfer the welded assembly to a two-stage cooling station for cooling; Use a white light interferometer to detect the flatness of the welding seam. When the height difference of the seam exceeds 2 μm, trigger the numerical control grinding device to trim the protruding part.

2. The welding method according to claim 1, characterized in that, The parameters of the pulsed laser welding equipment are set as follows: the laser wavelength is 1064 nm, the single pulse energy is 3 - 5 J, the pulse width is 2 - 4 ms, the pulse frequency is 10 - 15 Hz, and the spot diameter is 0.1 - 0.3 mm.

3. The welding method according to claim 2, wherein The defocus amount of the pulsed laser welding is set to +0.3~+0.4 mm, the front edge rise time of the laser pulse waveform is 1.5 - 2 ms, the trailing edge fall time ≤ 0.8 ms, and the laser power drops below 10% of the peak power within the adjacent pulse interval time.

4. The welding method according to claim 1, characterized in that, The grinding depth of the numerical control grinding device is set to 1 - 3 μm, the grinding speed is 200 - 300 r / min, the argon flow rate is controlled at 8 - 12 L / min, and the purging time is 20 - 30 seconds.

5. The welding method according to claim 1, characterized in that For the first stage of cooling in the two-stage cooling station, semi-conductor refrigeration sheet contact cooling is adopted, and the temperature of the cooling surface is maintained at 10 - 15 °C for continuous cooling for 60 - 90 seconds; for the second stage of cooling, aerosol mixed cooling is adopted, the compressed air pressure is 0.3 - 0.5 MPa, the atomized water droplet diameter is 20 - 50 μm, and the cooling time is 30 - 45 seconds.

6. The welding method according to claim 5, characterized in that, In the first stage of cooling, the cooling rate of the semi-conductor refrigeration sheet is controlled at 0.5 - 0.8 °C / s; in the aerosol mixed medium of the second stage of cooling, the volume ratio of water droplets to air is 1:15 - 1:20, and the aerosol spraying direction forms an angle of 45 - 60° with the welding plane.

7. The welding method according to claim 1, characterized in that, The vibration waveform of the piezoelectric ceramic fine adjuster is a rectangular wave with a duty cycle of 30 - 50%, and the vibration phase is synchronized with the rising edge of the pulsed laser, and the synchronization time deviation is less than 1 ms.

8. The welding method according to claim 1, wherein, The vacuum adsorption hole array is divided into three circles from the inside to the outside. The inner circle hole diameter is 0.3 - 0.5 mm, the middle circle hole diameter is 0.2 - 0.3 mm, and the outer circle hole diameter is 0.1 - 0.2 mm; the adjacent hole circle spacings are 2 mm, 1.5 mm and 1 mm respectively, and the included angle between the center connection lines of the adjacent layer holes is 22.5°.

9. The welding method according to claim 1, wherein The clamping surface of the clamp is covered with a polyimide insulation layer, the thickness of the polyimide insulation layer is 0.2-0.5 mm, the surface is laser etched to form a grid pattern, the texture depth is 5-8 μm, and the grid density is 20-30 lines / mm; at 25°C and 5N normal load, the static friction coefficient between the insulation layer and the metal structure is controlled in the range of 0.4-0.6, and the volume resistivity at 200°C is ≥1×10 14 Ω·cm.

10. A welding device for a small-sized metal sheet and a metal structural member in the field of microsensors, characterized in that, It includes: A vacuum adsorption table, on the surface of which there is a vacuum adsorption hole array. The vacuum adsorption table is connected to a vacuum pump, and the vacuum pump pressure control module sets the adsorption pressure to 0.05 - 0.08 MPa; Piezoelectric ceramic fine-tuning fixture, which includes jaws for clamping metal structural parts, a polyimide insulating layer covering the contact surface of the jaws, a piezoelectric ceramic actuator, and a clamping force sensor. The clamping force sensor is electrically connected to the piezoelectric ceramic actuator to control the clamping force to be 5 - 8N; Infrared temperature measurement module, which includes an infrared thermometer with a focused spot diameter of 0.5 - 0.8mm. The optical axis of the infrared thermometer is aligned with the center of the welding area, and the temperature measurement range is 50 - 150°C; Pulsed laser welding equipment, with a laser focusing lens group with a wavelength of 1064nm at the optical path outlet. The focal length adjustment mechanism of the laser focusing lens group is coaxially arranged with the vibration direction of the piezoelectric ceramic fine-tuning fixture; Vibration control module, which includes a vibration generator and a frequency controller connected to the piezoelectric ceramic fine-tuning fixture. The amplitude of the axial vibration output by the vibration generator is 2 - 5μm, and the vibration frequency is 50 - 100Hz; Argon protection unit, which includes a gas nozzle surrounding the welding area, an argon flow control valve, and an argon gas source. The spraying direction of the gas nozzle forms an angle of 30 - 45° with the welding plane; Two-stage cooling station, which includes a first-stage semiconductor refrigeration sheet contact cooling module and a second-stage aerosol mixing cooling module. The temperature controller of the refrigerating surface of the first-stage cooling module is set to 10 - 15°C. The second-stage cooling module includes a compressed air source, an atomizing nozzle, and a water droplet size controller. The compressed air pressure is set to 0.3 - 0.5MPa, and the atomized water droplet size is controlled to be 20 - 50μm; Detection and trimming unit, which includes a white light interferometer and a numerically controlled grinding device. The optical probe of the white light interferometer is vertically arranged with respect to the welding seam plane, and the detection accuracy is 0.1μm. The axial feed accuracy of the grinding head of the numerically controlled grinding device is 1μm, and the radial rotation speed is controlled to be 200 - 300r / min; Central control module, which is electrically connected to the vacuum pump pressure control module, the clamping force sensor, the infrared thermometer, the pulsed laser welding equipment, the vibration control module, the argon flow control valve, the two-stage cooling station, and the detection and trimming unit respectively. The central control module triggers pulsed laser welding according to the signal of the infrared thermometer, and controls the start and stop of the numerically controlled grinding device according to the detection result of the white light interferometer.

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