An apparatus and method for constant temperature soldering using a laser galvanometer

Abstract

The application discloses a device and method for constant-temperature welding using a laser galvanometer, and relates to the field of electronic component welding manufacturing. The device comprises a cabinet, a clamping and rotating module, a three-axis motion module, a laser welding module, a two-dimensional motion platform, a temperature monitoring module, a visual acquisition module and a software processing module. The method is as follows: a receiver containing a cross-shaped solder pad is fixed, moved to a coating position through the two-dimensional platform, the solder pad is rotated, the three-axis module drives a coating unit to coat tin along a V-shaped track, then moved to a welding position, a square light spot is shaped and welded through galvanometer scanning, real-time temperature control and visual verification are performed, and full-area welding is completed in four times of rotation. The application solves the problem of uneven heating of the cross-shaped solder pad, improves welding precision and yield, and is suitable for high-precision electronic component welding.

Description

Technical Field

[0001] This invention relates to the field of electronic component welding and manufacturing technology, specifically to an apparatus and method for isothermal welding using a laser galvanometer. Background Technology

[0002] As electronic devices evolve towards higher density and miniaturization, the demands for soldering precision and quality are increasing. Traditional solder paste soldering technology relies primarily on preset temperature profiles and fixed paths, making it difficult to adapt in real-time to the effects of material properties, environmental changes, and subtle differences in the soldering area. This leads to fluctuations in soldering quality and affects product yield. The improved technology utilizes a high-energy-density laser beam as a heat source, precisely targeting pre-coated or dispensing-positioned solder paste areas. This allows the paste to complete the melting-wetting-solidification process within milliseconds, achieving a metallurgical bond between the solder pads and component leads. Its core value lies in two aspects: firstly, by adjusting the laser power curve (e.g., stepped heating, isothermal reflow) to match the thermal capacity characteristics of different solder joints, significantly reducing thermal shock to surrounding sensitive components (e.g., MLCCs, crystal oscillators, FPCs); secondly, by leveraging a vision positioning system and a multi-axis motion platform, it achieves selective soldering with micron-level spatial resolution, perfectly adapting to complex scenarios such as partial rework after BGA underfill, soldering of fixed ends of flexible circuit boards, and connections between dissimilar materials (e.g., copper-aluminum). Currently, this technology has been widely applied in the manufacturing of 5G communication modules, automotive camera modules, medical wearable devices, and aerospace electronic components. It continues to evolve towards higher levels of automation and stronger process monitoring capabilities (such as closed-loop feedback of molten pool temperature). New processes drive product upgrades and showcase and apply more technologies. However, in the field of soldering for connecting terminals and pads on multi-layer PCB boards in mobile communication receiver modules, cross-shaped solder pads have the following drawbacks: cross-shaped solder pads are composed of solder pads spliced ​​together with gaps in between; there are differences in the circuits on the two solder pads; multi-axis platform soldering machines have sequential heating, resulting in a heating sequence; solder tends to flow towards the solder pads that heat up faster; and focusing head-type strip spot soldering machines, due to the gaps between the solder pads, result in uneven heating of the solder on the two solder pads, which can easily lead to broken connections, solder balls, and cold solder joints. Summary of the Invention

[0003] In view of the problems of soldering, disconnection, cold solder joints and solder balls in the 90-degree solder pad connection between multilayer PCBs and vertical PCBs in the prior art, the purpose of this invention is to provide a device and method for isothermal soldering using a laser galvanometer.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides an apparatus for isothermal welding using a laser galvanometer, comprising: Server rack; The clamping and rotating module clamps a receiver containing a cross-shaped pad formed by splicing multiple sub-pads, and can drive the cross-shaped pad and the receiver to rotate around a preset axis. The three-axis motion module fixes the solder paste coating unit and can drive the solder paste coating unit to move along the three-axis direction to the area to be soldered on the cross-shaped pad to apply solder paste. A laser welding module, mounted on the cabinet, includes a laser, a spot shaping module, a galvanometer unit, and a lifting adjustment unit. The spot shaping module is used to adjust the shape of the laser output spot. The lifting adjustment unit is used to adjust the relative height between the galvanometer unit and the cross-shaped welding pad to adjust the size of the laser output spot. The galvanometer unit is used to drive the laser beam to scan along a preset trajectory. A two-dimensional motion platform is mounted on the cabinet and connected to the clamping and rotating module, which can move the clamping and rotating module and the cross-shaped solder pad to the solder paste coating position or the laser welding position. Temperature monitoring module, used to collect surface temperature data of the welding area in real time; The vision acquisition module is used to acquire data on the position of the cross-shaped solder pads and the solder paste application status. The software processing module is electrically connected to the laser welding module, temperature monitoring module, and vision acquisition module, respectively, and can adjust the laser power, welding path, and welding speed according to the data from the temperature monitoring module and vision acquisition module.

[0005] As a preferred embodiment of the present invention, the spot shaping module includes a multi-section cylinder, a first spot shaping mirror, and a second spot shaping mirror, the distance between the first spot shaping mirror and the second spot shaping mirror being adjustable; the cylinder is fixed on the lifting adjustment unit and can drive it to rise and fall; the laser is connected to one end of the cylinder through a transmission optical fiber and an optical fiber coupling collimator; the galvanometer unit is provided at the other end of the cylinder; and a field lens and a vision light source are provided below the galvanometer unit.

[0006] As a preferred embodiment of the present invention, the visual acquisition module is disposed on the top of the cylinder. The visual acquisition module includes a visual acquisition camera, a filter, an imaging cemented lens, and a visual beam combiner arranged sequentially from top to bottom. The visual beam combiner is obliquely arranged on the laser path inside the cylinder and is used to receive visible light reflected by the field lens and galvanometer unit and reflect it to the visual acquisition camera through the imaging cemented lens and filter.

[0007] As a preferred embodiment of the present invention, the temperature monitoring module is disposed on the side of the cylinder, and the temperature monitoring module includes a polarizer and an infrared temperature probe. The infrared temperature probe points to the welding area of ​​the cross-shaped solder pad, and the polarizer is installed at the front end of the infrared temperature probe.

[0008] As a preferred embodiment of the present invention, the clamping and rotating module includes a rotary motor and a clamp. The rotary motor is fixed to a movable plate via a vertical plate, and the movable plate is slidably mounted on the two-dimensional motion platform. A frame is connected to the rotating end of the rotary motor, and a mounting plate is fixed on the frame. Two clamping cylinders are fixed on the mounting plate and arranged opposite to each other. A clamping space for clamping the clamp is formed between the two clamping cylinders. The clamp is used to clamp the receiver and fully expose the cross-shaped solder pad area on the receiver.

[0009] As a preferred embodiment of the present invention, the three-axis motion module includes an X-axis motion component, a Y-axis motion component, and a Z-axis motion component. The X-axis motion component is disposed on the cabinet, the Y-axis motion component is movably disposed on the X-axis motion component, and the Z-axis motion component is movably disposed on the Y-axis motion component. The X-axis motion component, Y-axis motion component, and Z-axis motion component are all arranged perpendicularly to each other, and the solder paste coating unit is disposed on the Z-axis motion component.

[0010] Secondly, this invention provides a welding method using the aforementioned device for isothermal welding with a laser galvanometer, comprising the following steps: S1: Fix the receiver containing the cross-shaped pad formed by splicing multiple sub-pads onto the clamping and rotating module, and fully expose the area to be soldered of the cross-shaped pad, so that the front of the cross-shaped pad faces upward. S2: Use a two-dimensional motion platform to move the cross-shaped pad to the solder paste application position. Use a clamping rotation module to rotate the cross-shaped pad 45° clockwise. Use a three-axis motion module to align the solder paste application unit with the first area to be soldered on the cross-shaped pad. S3: Apply solder paste to the first area to be soldered using the solder paste application unit, and adjust the application parameters to ensure that solder paste is applied to all the soldering positions on the first area to be soldered. S4: Use a two-dimensional motion platform to move the cross-shaped welding pad to the laser welding position. Adjust the shape, size and focusing position of the laser spot through the spot shaping module and the lifting adjustment unit so that the laser spot covers the width of the first area to be welded. S5: Start the laser and drive the laser beam to scan along the preset trajectory through the galvanometer unit. At the same time, the temperature monitoring module collects the temperature of the welding area, the vision acquisition module collects the pad position and solder paste coating status data, and the software processing module adjusts the laser power, scanning speed and path in real time according to the collected data. S6: After completing the soldering of the first area to be soldered, move the cross-shaped pad to the solder paste application position, rotate the cross-shaped pad 90° counterclockwise, and align the second area to be soldered with the solder paste application unit. Repeat S2-S5. After completing the soldering of the second area to be soldered, move the cross-shaped pad to the solder paste application position, rotate the cross-shaped pad 90° counterclockwise, and align the third area to be soldered with the solder paste application unit. Repeat S2-S5. After completing the soldering of the third area to be soldered, move the cross-shaped pad to the solder paste application position, rotate the cross-shaped pad 90° counterclockwise, and align the fourth area to be soldered with the solder paste application unit. Repeat S2-S5. Complete the soldering of the entire area of ​​the cross-shaped pad in four steps.

[0011] As a preferred embodiment of the present invention, the first, second, third, and fourth areas to be welded are all V-shaped structures with an included angle of 90°; the laser spot after being shaped by the spot shaping module is a square spot adapted to the areas to be welded.

[0012] As a preferred technical solution of the present invention, in step S3, the movement trajectory of the solder paste coating unit is a V-shaped trajectory, with one end of the length direction of the first area to be soldered as the starting coordinate, the bottom of the V-shape as the middle coordinate, and the other end as the ending coordinate; in step S5, the preset trajectory is: with one end of the length direction of the first area to be soldered as the starting point and the other end as the ending point, the trajectory is repeated multiple times.

[0013] As a preferred technical solution of the present invention, in step S5, the software processing module can determine whether the solder paste application position on the cross pad is accurate based on the solder paste image shape acquired by the vision acquisition module. If it is not accurate, it can be determined not to solder.

[0014] Compared with the prior art, the technical effects of the present invention are as follows: 1. This invention relies on the coordinated design of a temperature monitoring module (polarizer + infrared temperature probe) and a software processing module to achieve real-time and precise control of the soldering temperature. The infrared temperature probe is directly pointed at the soldering area of ​​the cross-shaped pad, and the front-end polarizer filters out stray light interference, ensuring minimal error in the collected surface temperature data. The software processing module receives temperature data in real time and dynamically adjusts the laser power and scanning speed based on the output characteristics of the laser (continuous-wave semiconductor laser). This ultimately avoids solder resist explosion and vaporization, voids in the solder joint, and solder ball splattering due to excessive temperature, or cold solder joints due to insufficient temperature, ensuring that the solder joint melts and solidifies within the optimal range of approximately 217℃ (the melting point of HX-WL680 solder paste), guaranteeing soldering consistency. This achieves high-precision constant-temperature closed-loop control, eliminating temperature-related soldering defects.

[0015] 2. The present invention realizes uniform heating of the bonding pads through the cooperative design of the light spot shaping module (multi-section cylinder body + first / second light spot shaping mirrors), the lifting adjustment unit and the galvanometer unit. Wherein, the spacing between the two light spot shaping mirrors is adjustable, which can shape the circular light spot output by the laser into a uniform energy square light spot with an aspect ratio of 2:1, adapting to the V-shaped to-be-welded area of the cross bonding pad (with an included angle of 90°); the lifting adjustment unit can drive the cylinder body to lift and lower, precisely adjust the relative height between the galvanometer unit and the bonding pad, and ensure that the light spot covers the width direction of the to-be-welded area; the galvanometer unit drives the laser to scan along a preset trajectory, replacing the traditional "sequential heating" mode of the multi-axis platform or the "gap heat leakage of strip light spot" mode of the focusing head, and thoroughly solves the problems of disconnection and cold welding caused by uneven heating of the cross bonding pad (with a sub-pad spacing of 1 mm). The present invention solves the problem of uneven heating of cross bonding pads through square light spot + galvanometer scanning.

[0016] 3. The present invention realizes comprehensive and precise welding of cross bonding pads by combining the structural design of the clamping rotation module, the three-axis movement module and the two-dimensional movement platform. Wherein, the clamping rotation module realizes 360° adjustable rotation through a rotating motor, and rotates the cross bonding pad to the to-be-welded angle 4 times in total (for example, rotate 45° clockwise for the first time to align with the first V-shaped area, and then rotate 90° counterclockwise each time afterwards), and cooperates with the two-dimensional movement platform to switch between "solder paste coating position - laser welding position", ensuring that no 4 V-shaped areas are omitted. The three-axis movement module (vertical linkage of X / Y / Z axes) drives the solder paste coating unit to coat along the V-shaped trajectory, ensuring that each sub-pad is precisely covered with solder paste, and the solder paste between adjacent sub-pads does not adhere. The present invention achieves precise coating and full-area coverage through multi-module linkage, leaving no welding dead angles.

[0017] 4. The present invention realizes double quality inspection before and during welding based on the image analysis capabilities of the visual acquisition module and the software processing module. Wherein, the visual acquisition module adopts a structure of "visual acquisition camera + filter plate + imaging cemented lens + obliquely arranged visual beam combiner", and accurately collects the bonding pad position and the solder paste coating state (shape, position) through the field lens and the visible light reflected by the galvanometer unit. The software processing module can automatically identify the coating deviation of solder paste (such as misalignment with the V-shaped area), directly determine "do not start welding", and avoid wrong welding and missing welding from the source; meanwhile, it can dynamically correct the welding trajectory according to image data, avoid solder joint deviation caused by workpiece assembly errors, and significantly reduce the defective rate of products. The present invention greatly reduces the defective rate through visual-guided intelligent quality control.

[0018] 5. The collaborative automated design of each module in this invention shortens the production cycle and adapts to large-scale mass production. The entire process, from "workpiece fixing (clamping and rotating module) → solder paste application (three-axis motion module) → welding (laser welding module) → switching to the next area (two-dimensional motion platform + rotary motor)," requires no manual intervention and can complete the welding of the entire cross-shaped pad in just four steps. The software processing module integrates parameter settings (laser power, scanning speed, coating air pressure, etc.), data acquisition (temperature, images), and abnormal alarm functions (such as temperature exceeding limits, coating abnormalities). Operators only need to monitor through the cabinet's display screen. Single-station production efficiency is increased by more than 30% compared to traditional equipment. High automation and linkage improve production efficiency and reduce manual intervention. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the device of the present invention.

[0020] Figure 2 This is a partial structural schematic diagram of the device of the present invention.

[0021] Figure 3 for Figure 2 A top-view structural diagram.

[0022] Figure 4 This is a schematic diagram of the optical path structure of the laser structure of the present invention.

[0023] Figure 5 This is a schematic diagram of the receiver of the present invention.

[0024] Figure 6 This is a schematic diagram of the cross-shaped solder pad of the present invention.

[0025] Figure 7 This is a schematic diagram of the structure for fixing the receiver and the clamp in this invention.

[0026] Figure 8 This is a schematic diagram of the receiver and clamping rotation module of the present invention.

[0027] Reference numerals: 1. Cabinet; 101. Monitor; 102. Electrical control cabinet; 103. Three-color lighthouse; 104. Keyboard and keypad area; 2. Clamping rotation module; 201. Rotary motor; 202. Clamp; 203. Vertical plate; 204. Moving plate; 205. Frame; 206. Mounting plate; 207. Clamping cylinder; 3. Three-axis motion module; 301. X-axis motion assembly; 302. Y-axis motion assembly; 303. Z-axis motion assembly; 4. Laser welding module; 401. Laser; 402. Spot shaping module; 403. Galvanometer unit; 404. Lifting and adjusting unit; 405. Cylinder; 406. First spot shaping mirror; 407. Second spot shaping mirror; 408. Transmission fiber; 409. Fiber optic coupler collimator; 410. Field lens; 411. Visual light source; 412. X-axis deflecting lens; 413. Y-axis deflecting lens; 5. Two-dimensional motion platform; 6. Temperature monitoring module; 601. Polarizer; 602. Infrared temperature probe; 7. Visual acquisition module; 701. Visual acquisition camera; 702. Filter; 703. Imaging cemented lens; 704. Visual beam combiner; 8. Cross-shaped solder pad; 9. Receiver; 10. Solder paste coating unit; 11. Glue spray valve controller; 12. Industrial computer. Detailed Implementation

[0028] To make the technical solution, objectives, and advantages of the present invention clearer, the following description is provided in conjunction with the appendix. Figure 4-8 The present invention provides a more detailed description of the apparatus and method for isothermal welding using a laser galvanometer, including specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and do not constitute a limitation thereof; the accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of protection of this patent. Some components may be omitted, enlarged, or reduced in the drawings, and their proportions do not represent the actual product dimensions; for those skilled in the art, the omission of some well-known structures and descriptions in the drawings is understandable, and the positional relationships described in the drawings are for illustrative purposes only and do not constitute a limitation thereof.

[0029] like Figures 1-8 As shown, this embodiment of the invention provides a device for isothermal welding using a laser galvanometer, comprising: a cabinet 1, a clamping and rotating module 2, a three-axis motion module 3, a laser welding module 4, a two-dimensional motion platform 5, a temperature monitoring module 6, a vision acquisition module 7, and a software processing module. A display 101 is mounted on the side of the cabinet 1, an electrical control cabinet 102 is mounted in the lower half of the cabinet 1, a three-color lighthouse 103 is mounted on the top of the cabinet 1, and a keyboard and keypad 104 are mounted in the middle of the cabinet 1.

[0030] In some examples, the clamping rotation module 2 clamps the receiver 9 containing a cross-shaped pad 8 formed by splicing multiple sub-pads, and can drive the cross-shaped pad 8 and the receiver 9 to rotate around a preset axis.

[0031] Specifically, such as Figure 8 As shown, the clamping and rotating module 2 includes a rotary motor 201 and a clamp 202. The rotary motor 201 is fixed to a movable plate 204 via a vertical plate 203. The movable plate 204 is slidably mounted on a two-dimensional motion platform 5. A frame 205 is connected to the rotating end of the rotary motor 201. A mounting plate 206 is fixed to the frame 205. Two clamping cylinders 207 are fixed on the mounting plate 206 and arranged opposite to each other. A clamping space for clamping the clamp 202 is formed between the two clamping cylinders 207. The clamp 202 is used to clamp the receiver 9 and fully expose the cross-shaped solder pad 8 area on the receiver 9. The rotary motor 201 can drive the product on the clamp 202 to rotate 360° at any angle, and can rotate to any desired angle.

[0032] Optionally, such as Figure 7 As shown, the fixture 202, through its inner edge contour design, holds the receiver 9 on both sides, exposing the area to be soldered on the cross-shaped solder pad 8. Both outer edges of the fixture 202 have protrusions, and the two clamping cylinders 207, through U-shaped positioning blocks, clamp the protrusions on both sides of the fixture 202, thereby fixing the fixture 202 in place.

[0033] In some examples, the three-axis motion module 3 fixes the solder paste application unit 10 and can drive the solder paste application unit 10 to move along the three-axis direction to the area to be soldered on the cross-shaped pad 8 to apply solder paste.

[0034] Specifically, such as Figure 2 and Figure 3 As shown, the three-axis motion module 3 includes an X-axis motion component 301, a Y-axis motion component 302, and a Z-axis motion component 303. The X-axis motion component is mounted on the cabinet 1, the Y-axis motion component is movably mounted on the X-axis motion component, and the Z-axis motion component is movably mounted on the Y-axis motion component. The X-axis, Y-axis, and Z-axis motion components are all arranged perpendicularly to each other. The solder paste application unit 10 is mounted on the Z-axis motion component. The X, Y, and Z-axis motion components all move in three directions with the cooperation of motors and slide rails. Their specific structure and working principle are existing technologies and will not be described in detail in this invention.

[0035] Specifically, such as Figure 2As shown, the solder paste coating unit 10 includes a pneumatic spray valve and a solder paste cartridge. The software processing module can adjust the air pressure, coating time, movement trajectory, and paste dispensing amount of the spray valve to achieve precise solder paste coating on different areas of the cross-shaped pads 8. The weight of the solder paste is determined according to the size of the pads to ensure that the flux covers all the cross-shaped pads required for laser welding. The solder paste used is HX-WL680 laser solder paste, a lead-free, no-clean solder paste composed of tin-silver-copper (Sn96.5Ag3Cu0.5) lead-free high-silver alloy solder powder and a special active system. It is a high-temperature solder paste with a minimum laser welding time of less than 300 milliseconds and a melting point of 217 degrees Celsius.

[0036] In some examples, such as Figure 2 and Figure 3 As shown, the laser welding module 4 is mounted on the cabinet 1 and includes a laser 401, a spot shaping module 402, a galvanometer unit 403, and a lifting adjustment unit 404. The spot shaping module 402 is used to adjust the shape of the laser spot output by the laser 401. The lifting adjustment unit 404 is used to adjust the relative height between the galvanometer unit 403 and the cross-shaped welding pad 8 to adjust the size of the laser spot output by the laser 401. The galvanometer unit 403 is used to drive the laser beam to scan along a preset trajectory.

[0037] Specifically, the light energy of the continuous semiconductor laser 401 is used, and the laser parameters are: wavelength of 915 nanoseconds, average power between 100-200 watts, beam quality M2 factor less than or equal to 1.2. The laser 401 is a continuous semiconductor laser 401, and the frequency and pulse width cannot be set. The output spot size of the laser 401 is 3-5 mm. The ellipticity of the output spot is greater than 90%, the beam divergence angle is less than 0.5 milliradians, the laser has no peak power, the average power is very stable, the thermal conversion efficiency is high, and the energy distribution is uniform.

[0038] Specifically, such as Figure 4 As shown, the beam shaping module 402 includes a fixed cylinder 405, a rotatable cylinder 405, a first beam shaping mirror 406, and a second beam shaping mirror 407. The first beam shaping mirror 406 is disposed inside the rotatable cylinder 405, and the second beam shaping mirror 407 is disposed inside the fixed cylinder 405. The fixed cylinder 405 and the rotatable cylinder 405 are threadedly connected. The distance between the first beam shaping mirror 406 and the second beam shaping mirror 407 can be adjusted by rotating the rotatable cylinder 405, thereby adjusting the shape of the beam output by the laser 401. The beam shaping module 402 can shape the circular beam output by the laser 401 into a square beam with a uniform energy distribution and an aspect ratio of 2:1.

[0039] Specifically, the lifting and adjusting unit 404 is used to install and fix the cylinder 405 and can drive it to rise and fall. The laser 401 is connected to one end of the rotatable cylinder 405 through the transmission fiber 408 and the fiber optic coupler collimator 409. The other end of the fixed cylinder 405 is provided with a galvanometer unit 403. Below the galvanometer unit 403, a field lens 410 and a vision light source 411 are provided. The galvanometer unit 403 includes an X-axis deflecting lens 412 and a Y-axis deflecting lens 413. The galvanometer aperture is 20 mm, and the reflective film is an infrared reflective film with a wavelength of 400-1000 nanometers and 7-13.5 micrometers. The galvanometer movement speed is adjustable from 0-700 mm per second. The field lens 410 is a lens with a focal length selectable from 163-255 mm. The height of the laser welding module 4 is adjusted by the lifting and adjusting unit 404 to adjust the required square spot size.

[0040] In some examples, the two-dimensional motion platform 5 is mounted on the cabinet 1 and connected to the clamping and rotating module 2, which can move the clamping and rotating module 2 and the cross-shaped solder pad 8 to the solder paste application position or the laser welding position.

[0041] In some examples, temperature monitoring module 6 is used to collect surface temperature data of the welding area in real time.

[0042] Specifically, such as Figure 4 As shown, the temperature monitoring module 6 is located on the side of the fixed cylinder 405. The temperature monitoring module 6 includes a polarizer 601 and an infrared temperature probe 602. The infrared temperature probe 602 points towards the soldering area of ​​the cross-shaped solder pad 8, and the polarizer 601 is installed at the front end of the infrared temperature probe 602. The infrared temperature module can monitor the temperature of the solder paste in real time, reflect it to the software, and adjust the laser energy in real time to control the temperature of the solder paste, preventing the solder resist from exploding, vaporizing, forming voids, spatter, and solder balls due to excessive temperature.

[0043] In some examples, the vision acquisition module 7 is used to acquire data on the pad position and solder paste application status of the cross-shaped pad 8.

[0044] Specifically, such as Figure 4 As shown, the vision acquisition module 7 is located on the top of the fixed cylinder 405. The vision acquisition module 7 includes a vision acquisition camera 701 (Hikvision industrial camera), a filter 702, an imaging cemented lens 703, and a vision beam combiner 704 arranged sequentially from top to bottom. The vision beam combiner 704 is inclinedly arranged on the laser path inside the cylinder 405 to receive the visible light reflected by the field lens 410 and the galvanometer unit 403 and reflect it through the imaging cemented lens 703 and the filter 702 to the vision acquisition camera 701.

[0045] In some examples, the software processing module is electrically connected to the laser welding module 4, the temperature monitoring module 6, and the vision acquisition module 7, respectively, and can adjust the laser power, welding path, and welding speed based on the data from the temperature monitoring module 6 and the vision acquisition module 7.

[0046] Specifically, the software processing module can also form a soldering position trajectory based on the image acquired by the vision acquisition module 7, ensuring that the soldering position is not offset due to the installation and assembly error of the fixture 202. At the same time, it can also determine whether the position of the pneumatic valve spraying solder paste is correct based on the image shape of the solder paste in the image that can be acquired by the vision module. If it is incorrect, it can be determined not to solder, thereby reducing the soldering defect rate.

[0047] Based on a general inventive concept, this invention also provides a method for isothermal welding using a laser galvanometer, for processing the cross-shaped solder pads of a multilayer PCB assembly board in a 5G network receiver (9 components). Figure 5 and Figure 6 As shown, the front of the composite board has four vertical pads (A2, B2, C2, D2) and four horizontal pads (A1, B1, C1, D1). Each pad is 0.5 mm wide and 2 mm long, with a 1 mm spacing between them. A1 and A2, B1 and B2, C1 and C2, and D1 and D2 need to be soldered together to form the left area of ​​the cross-shaped pads on the front. The other areas of the cross-shaped pads are rotated to the front using a rotary motor 201, and the same method is used to laser solder the solder paste in sequence.

[0048] First, install and debug the pneumatic spray valve. The pneumatic spray valve is installed on the XYZ three-axis linkage mechanism. The air pressure of the pneumatic spray valve and the opening and closing of the solder paste spraying are adjusted by the spray valve controller 11. The XYZ three-axis motion trajectory control completes the full coverage of the cross pads to form multiple V-shaped splicing pads. Install and debug the optical system of the soldering equipment, infrared temperature measurement module, vision acquisition module 7, spot shaping module 402, laser 401 and electrical control module. The light spot from the laser 401 is transmitted through optical fiber to the shaping module, galvanometer, field lens 410, and then focused into a square light spot that acts on the solder paste.

[0049] Specifically, the following steps are included: Step 1: Place the receiver 9 containing the cross-shaped pad 8 formed by splicing multiple sub-pads on the fixture 202, then place the fixture 202 on the mounting plate 206 and clamp it in place by the clamping cylinder 207. The cross-shaped pad 8 is fixed horizontally, and the area to be soldered on the cross-shaped pad 8 is fully exposed, so that the front of the cross-shaped pad 8 is facing up.

[0050] Specifically, the areas to be soldered on the cross-shaped solder pad 8 are divided into a first area to be soldered, a second area to be soldered, a third area to be soldered, and a fourth area to be soldered, and each area to be soldered is a V-shaped structure with an included angle of 90°.

[0051] Step 2: Use the two-dimensional motion platform 5 to move the cross-shaped pad 8 to the solder paste application position. Use the rotary motor 201 to drive the fixture 202 and the cross-shaped pad 8 to rotate 45° clockwise. Use the three-axis motion module 3 to align the solder paste application unit 10 with the first area to be soldered on the cross-shaped pad 8. The moving speed is 200 mm / s.

[0052] Specifically, the rotation speed of the rotary motor 201 is 1 second / revolution, ensuring that the area to be applied solder paste on the left half of the front side of the cross pad is within the movement trajectory of the pneumatic spray valve, and the 90° V-shaped pad spliced ​​by pads A1 and A2, B1 and B2, C1 and C2, and D1 and D2 is under the pneumatic spray valve.

[0053] S3: Solder paste is applied to the first area to be soldered by the solder paste application unit 10, and the application parameters are adjusted to ensure that solder paste is applied to all the positions to be soldered on the first area to be soldered.

[0054] Specifically, install the HX-WL680 laser solder paste on the pneumatic spray valve, adjust the air pressure of the pneumatic spray valve to 0.25 PA, and set the X / Y / Z axis speed to 4 mm / s while spraying solder paste. The idle speed of the X, Y, and Z axes should be 50 mm / s. Use the left point of pad A1 as the starting coordinate, edit the V-shaped trajectory, with the bottom of the V-shape as the middle coordinate and the right side of pad A2 as the endpoint. Spray solder paste from top to bottom and then from bottom to top along the V-shaped trajectory on the upper surfaces of A1 and A2. Pause for 0.2 seconds in the middle of the V-shape to ensure that the solder paste fills the V-groove. Continue to spray solder paste on B1 and B2, C1 and C2, and D1 and D2. Apply solder paste to all the positions to be soldered on the left half of the cross pads on the front side. Do not connect the solder paste between each spliced ​​pad.

[0055] S4: The two-dimensional motion platform 5 is used to move the cross-shaped welding pad 8 to the laser welding position. The laser spot shape, size and focusing position are adjusted by the spot shaping module 402 and the lifting adjustment unit 404 so that the laser spot covers the width direction of the first area to be welded.

[0056] Specifically, the two-dimensional motion platform 5 moves at a speed of 200 mm / s, the rotary motor 201 remains stationary, and the rotation axis is stationary. The size of the laser stripe spot and the height of the laser galvanometer are adjusted so that the laser spot covers the welded cross-shaped pads. The spot size is 5 mm in length and 2.5 mm in width, with the 5 mm long spot covering the width directions of A1, B1, C1, and D1.

[0057] S5: Start the laser 401 and drive the laser beam to scan along the preset trajectory through the galvanometer unit 403. At the same time, the temperature monitoring module 6 collects the temperature of the welding area, and the vision acquisition module 7 collects the pad position and solder paste coating status data. The software processing module adjusts the laser power, scanning speed and path in real time according to the collected data.

[0058] Specifically, the soldering trajectory in the software is edited to start from the left pad of A1 and end at the right pad of A2, repeating the trajectory three times. The laser 401 is set to limit power to 70%, upper temperature limit to 230 degrees, and the galvanometer movement speed (X-axis and Y-axis soldering speed) is set to 15 mm / s.

[0059] S6: After completing the soldering of the first area to be soldered, the two-dimensional motion platform 5 moves the cross-shaped pad 8 to the solder paste application position and rotates the cross-shaped pad 8 90° counterclockwise so that the second area to be soldered (the right half of the V-shaped area on the front side) of the cross-shaped pad is aligned with the solder paste application unit 10. Repeat S2-S5. After completing the soldering of the second area to be soldered, the two-dimensional motion platform 5 moves the cross-shaped pad 8 to the solder paste application position and rotates the cross-shaped pad 8 90° counterclockwise so that the third area to be soldered (the left half of the V-shaped area on the back side) of the cross-shaped pad is aligned with the solder paste application unit 10. Repeat S2-S5. After completing the soldering of the third area to be soldered, the two-dimensional motion platform 5 moves the cross-shaped pad 8 to the solder paste application position and rotates the cross-shaped pad 8 90° counterclockwise so that the fourth area to be soldered (the right half of the V-shaped area on the back side) of the cross-shaped pad is aligned with the solder paste application unit 10. Repeat S2-S5. The soldering of the entire area of ​​the cross-shaped pad 8 is completed in four steps.

[0060] Based on the description and accompanying drawings of this invention, those skilled in the art can readily manufacture or use the apparatus and method for isothermal welding using a laser galvanometer according to this invention, and can achieve the positive effects described in this invention.

[0061] Unless otherwise specified, in this invention, terms such as "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe orientation or positional relationships in this invention are for illustrative purposes only and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood in conjunction with the accompanying drawings and according to the specific circumstances.

[0062] Unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" in this invention should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. An apparatus for isothermal welding using a laser galvanometer, characterized in that, include: Server rack (1); The clamping rotation module (2) clamps the receiver (9) containing a cross-shaped pad (8) formed by splicing multiple sub-pads, and can drive the cross-shaped pad (8) and the receiver (9) to rotate around a preset axis. The three-axis motion module (3) fixes the solder paste coating unit (10) and can drive the solder paste coating unit (10) to move along the three-axis direction to the area to be soldered on the cross-shaped pad (8) to apply solder paste. A laser welding module (4), mounted on the cabinet (1), includes a laser (401), a spot shaping module (402), a galvanometer unit (403), and a lifting adjustment unit (404). The spot shaping module (402) is used to adjust the shape of the laser spot output by the laser (401). The lifting adjustment unit (404) is used to adjust the relative height between the galvanometer unit (403) and the cross-shaped welding pad (8) to adjust the size of the laser spot output by the laser (401). The galvanometer unit (403) is used to drive the laser beam to scan along a preset trajectory. The spot shaping module (402) includes multiple cylindrical sections (40... 5) A first spot shaping mirror (406) and a second spot shaping mirror (407), the distance between the first spot shaping mirror (406) and the second spot shaping mirror (407) is adjustable; the cylinder (405) is fixed on the lifting adjustment unit (404) and can drive it to rise and fall; the laser (401) is connected to one end of the cylinder (405) through the transmission fiber (408) and the fiber coupling collimator (409); the other end of the cylinder (405) is provided with the galvanometer unit (403); the field lens (410) and the visual light source (411) are provided below the galvanometer unit (403). A two-dimensional motion platform (5) is set on the cabinet (1) and connected to the clamping rotation module (2). It can drive the clamping rotation module (2) and the cross-shaped solder pad (8) to move to the solder paste coating position or the laser welding position. Temperature monitoring module (6) is used to collect surface temperature data of the welding area in real time; A vision acquisition module (7) is used to acquire data on the pad position and solder paste coating status of the cross-shaped pad (8). The vision acquisition module (7) is located on the top of the cylinder (405). The vision acquisition module (7) includes a vision acquisition camera (701), a filter (702), an imaging cemented lens (703), and a vision beam combiner (704) arranged sequentially from top to bottom. The vision beam combiner (704) is inclinedly arranged on the laser path inside the cylinder (405) to receive visible light reflected by the field lens (410) and the galvanometer unit (403) and transmit it to the vision acquisition camera (701) through the imaging cemented lens (703) and the filter (702). The software processing module is electrically connected to the laser welding module (4), the temperature monitoring module (6) and the vision acquisition module (7) respectively. It can adjust the laser power, welding path and welding speed according to the data of the temperature monitoring module (6) and the vision acquisition module (7).

2. The apparatus for isothermal welding using a laser galvanometer according to claim 1, characterized in that, The temperature monitoring module (6) is located on the side of the cylinder (405). The temperature monitoring module (6) includes a polarizer (601) and an infrared temperature probe (602). The infrared temperature probe (602) points to the welding area of ​​the cross-shaped pad (8). The polarizer (601) is installed at the front end of the infrared temperature probe (602).

3. The apparatus for isothermal welding using a laser galvanometer according to claim 1, characterized in that, The clamping rotation module (2) includes a rotary motor (201) and a clamp (202). The rotary motor (201) is fixed to a movable plate (204) via a vertical plate (203). The movable plate (204) is slidably mounted on the two-dimensional motion platform (5). The rotating end of the rotary motor (201) is connected to a frame (205). A mounting plate (206) is fixed on the frame (205). Two clamping cylinders (207) are fixed on the mounting plate (206) and arranged opposite to each other. A clamping space for clamping the clamp (202) is formed between the two clamping cylinders (207). The clamp (202) is used to clamp the receiver (9) and fully expose the cross-shaped solder pad (8) area on the receiver (9).

4. The apparatus for isothermal welding using a laser galvanometer according to claim 1, characterized in that, The three-axis motion module (3) includes an X-axis motion component (301), a Y-axis motion component (302), and a Z-axis motion component (303). The X-axis motion component (301) is mounted on the cabinet (1). The Y-axis motion component (302) is movably mounted on the X-axis motion component (301). The Z-axis motion component (303) is movably mounted on the Y-axis motion component (302). The X-axis motion component (301), Y-axis motion component (302), and Z-axis motion component (303) are all arranged perpendicularly to each other. The solder paste coating unit (10) is mounted on the Z-axis motion component (303).

5. A welding method using the apparatus for isothermal welding with a laser galvanometer as described in any one of claims 1-4, characterized in that, Includes the following steps: S1: Fix the receiver (9) containing a cross-shaped pad (8) formed by splicing multiple sub-pads onto the clamping and rotating module (2), and fully expose the area to be soldered of the cross-shaped pad (8), so that the front of the cross-shaped pad (8) faces upward. S2: Using the two-dimensional motion platform (5), the cross-shaped pad (8) is moved to the solder paste application position. The cross-shaped pad (8) is rotated 45° clockwise by the clamping rotation module (2). The solder paste application unit (10) is aligned with the first area to be soldered on the cross-shaped pad (8) by the three-axis motion module (3). S3: Apply solder paste to the first area to be soldered through the solder paste application unit (10), and adjust the application parameters to ensure that the soldering positions on the first area to be soldered are all covered with solder paste; S4: Using a two-dimensional motion platform (5), the cross-shaped welding pad (8) is moved to the laser welding position. The shape, size and focusing position of the laser spot are adjusted by the spot shaping module (402) and the lifting adjustment unit (404) so ​​that the laser spot covers the width direction of the first area to be welded. S5: Start the laser (401), drive the laser beam to scan along the preset trajectory through the galvanometer unit (403), and at the same time use the temperature monitoring module (6) to collect the temperature of the welding area, and the vision acquisition module (7) to collect the pad position and solder paste coating status data. The software processing module adjusts the laser power, scanning speed and path in real time according to the collected data. S6: After completing the first area to be soldered, move the cross-shaped pad (8) to the solder paste application position, rotate the cross-shaped pad (8) 90° counterclockwise, so that the second area to be soldered of the cross-shaped pad (8) is aligned with the solder paste application unit (10). Repeat S2-S5. After completing the second area to be soldered, move the cross-shaped pad (8) to the solder paste application position, rotate the cross-shaped pad (8) 90° counterclockwise, so that the third area to be soldered of the cross-shaped pad (8) is aligned with the solder paste application unit (10). Repeat S2-S5. After completing the third area to be soldered, move the cross-shaped pad (8) to the solder paste application position, rotate the cross-shaped pad (8) 90° counterclockwise, so that the fourth area to be soldered of the cross-shaped pad (8) is aligned with the solder paste application unit (10). Repeat S2-S5. Complete the soldering of the entire area of ​​the cross-shaped pad (8) in four steps.

6. The welding method according to claim 5, characterized in that, The first, second, third, and fourth areas to be welded are all V-shaped structures with an included angle of 90°; the laser spot after being shaped by the spot shaping module (402) is a square spot adapted to the area to be welded.

7. The welding method according to claim 5, characterized in that, In step S3, the movement trajectory of the solder paste coating unit (10) is a V-shaped trajectory, with one end of the length direction of the first area to be soldered as the starting coordinate, the bottom of the V-shape as the middle coordinate, and the other end as the ending coordinate; in step S5, the preset trajectory is: with one end of the length direction of the first area to be soldered as the starting point and the other end as the ending point, it cycles back and forth multiple times.

8. The welding method according to claim 5, characterized in that, In step S5, the software processing module can determine whether the solder paste coating position on the cross-shaped pad (8) is accurate based on the solder paste image shape acquired by the vision acquisition module (7). If it is not accurate, it can be determined not to solder.

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