Multi-wavelength composite laser welding device

Abstract

The invention discloses a multi-wavelength composite laser welding device, which relates to the technical field of laser welding, and comprises a beam combining box I. The left side of the beam combining box I is fixedly connected with a beam combining box II, and a dichroscope I and a dichroscope II are respectively arranged in the beam combining box I and the beam combining box II; according to the invention, a blue light, near-infrared and mid-infrared three-wavelength independent laser module design is adopted, and a special electro-optical switch is configured for each wavelength light path. Flexible switching of single-wavelength independent light emitting, dual-wavelength collaborative light emitting or three-wavelength synchronous light emitting can be achieved through an external high-voltage driving circuit, the light emitting time sequence and the conduction time length of each wavelength can be regulated and controlled through an electro-optical switch, light path parameters can be dynamically adjusted according to the requirements of different stages of the whole welding process, refined control over the welding process is achieved, and the welding quality is improved. And the welding quality consistency under the complex working condition is improved.

Description

A multi-wavelength composite laser welding device Technical Field

[0001] This invention relates to the field of laser welding technology, specifically to a multi-wavelength composite laser welding device. Background Technology

[0002] Laser welding is a highly efficient and precise welding method that uses a high-energy-density laser beam as a heat source. It is an important application of laser materials processing technology. In the 1970s, it was mainly used for welding thin-walled materials and low-speed welding. The welding process is heat conduction type, meaning that laser radiation heats the surface of the workpiece, and the surface heat diffuses inward through heat conduction. By controlling parameters such as the width, energy, peak power, and repetition frequency of the laser pulse, the workpiece is melted to form a specific molten pool. Due to its unique advantages, it has been successfully applied to the precision welding of micro and small parts.

[0003] Existing devices mostly employ a dual-wavelength composite design, which can only achieve synchronous output with a fixed energy ratio. It is difficult to dynamically adjust the light output sequence according to the needs of the entire welding process. Furthermore, after beam combining, the spot shape is uniformly shaped, making it difficult to independently control the spot shape and focusing depth for each wavelength, resulting in reduced device adaptability. At the same time, some stray light is present during laser collimation. This stray light and stray light enter subsequent optical components, affecting the beam quality and welding accuracy. In addition, after multi-wavelength laser beam combining, due to the certain chromatic aberration of different laser beams, some lasers in the beam will be deflected during laser focusing, causing minor errors in the welding process and affecting welding precision. Therefore, a multi-wavelength composite laser welding device is proposed to solve the problems mentioned above. Summary of the Invention

[0004] To address the aforementioned technical problems, a multi-wavelength composite laser welding device is provided. This technical solution solves the problems mentioned in the background art, where existing devices mostly adopt a dual-wavelength composite design, which can only achieve synchronous output with a fixed energy ratio. It is difficult to dynamically adjust the light output sequence according to the needs of the entire welding process. Furthermore, after beam combining, the spot shape is uniformly shaped, making it difficult to independently control the spot shape and focusing depth for each wavelength, resulting in reduced device adaptability. At the same time, during laser collimation, some stray light will exist. This stray light and stray light will enter the subsequent optical components, affecting the beam quality and welding accuracy. In addition, after multi-wavelength laser beam combining, due to the certain chromatic aberration of different laser beams, some lasers in the beam will be deflected when the laser is focused, causing small errors in the welding process and affecting the welding accuracy.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a multi-wavelength composite laser welding device, comprising a beam combiner box 1, a beam combiner box 2 fixedly connected to the left side of the beam combiner box 1, and a dichroic mirror 1 and a dichroic mirror 2 respectively disposed inside the beam combiner box 1 and the beam combiner box 2 for spatial coaxial beam combining of blue light, near-infrared and mid-infrared lasers. Beam shaping boxes are fixedly connected to the upper and left ends of the beam combiner box 2 and the lower end of the beam combiner box 1. Blue light collimators, near-infrared collimators and mid-infrared collimators are fixedly connected to the other ends of the three beam shaping boxes respectively. Blue light laser modules, near-infrared laser modules and mid-infrared laser modules are sequentially fixedly connected to the other ends of the blue light collimators, near-infrared collimators and mid-infrared collimators. The blue light collimator is arranged from left to right as follows: The system includes a front aperture, a blue collimating lens group, a rear aperture, and a blue electro-optic switch, which are used for electronically controlling the suppression of incident stray light, collimation and shaping, edge stray light constraint, and optical path on / off switching of the blue laser beam, respectively. The near-infrared collimator has a front aperture, a near-infrared collimating lens group, a rear aperture, and a near-infrared electro-optic switch arranged from top to bottom, which are used for electronically controlling the filtering of incident stray light, collimation and shaping, edge diffraction stray light constraint, and optical path on / off switching of the near-infrared laser beam, respectively. The mid-infrared collimator has a front aperture, a zinc selenide meniscus collimating lens, a rear aperture, and a mid-infrared electro-optic switch arranged from bottom to top, which are used for electronically controlling the suppression of incident stray light, collimation and shaping, beam aperture constraint, and optical path on / off switching of the mid-infrared laser beam, respectively.

[0006] Preferably, the blue light collimating lens group includes a crown glass positive lens and a flint glass negative lens, which are arranged sequentially along the blue light laser emission direction. The crown glass positive lens and the flint glass negative lens are bonded together without gaps using optical epoxy adhesive to form an integrated bonding surface. The cross-section of the crown glass positive lens along the optical axis is biconvex, and both optical surfaces are spherical. The radius of curvature of the incident surface is greater than the radius of curvature of the bonding surface. The exit surface of the flint glass negative lens is a plane, and the incident surface is a concave spherical surface, which has the same absolute value as the radius of curvature of the bonding surface of the crown glass positive lens. The two spherical surfaces are tightly bonded together.

[0007] Preferably, the inner side of the first front aperture is machined with an anti-glare thread, the inner side of the first rear aperture is nested with an anti-glare bushing, the blue photoelectric switch is a KDP electro-optic crystal, and the two light-transmitting sides of the blue photoelectric switch are provided with oxygen-free copper gold-plated electrode sheets, which are connected to an external high-voltage driving circuit to provide a uniform electric field for the crystal.

[0008] Preferably, the near-infrared collimating lens assembly includes a cylindrical lens mount, a fused silica meniscus lens, and a fused silica plano-convex lens. The cylindrical lens mount is fixedly connected inside the near-infrared collimator. The fused silica meniscus lens and the fused silica plano-convex lens are both installed inside the cylindrical lens mount and arranged sequentially along the near-infrared laser emission direction. The incident surface of the fused silica meniscus lens is concave, and the exit surface is convex. The incident surface of the fused silica plano-convex lens is convex, and the exit surface is planar. An air gap is formed between the fused silica meniscus lens and the fused silica plano-convex lens.

[0009] Preferably, the inner side of the second front aperture is nested with a light trap structure, the inner side of the second rear aperture is nested with an extinction bushing, the near-infrared electro-optic switch is a lithium niobate electro-optic crystal, and the two light-transmitting sides of the near-infrared electro-optic switch are provided with oxygen-free copper gold-plated electrode sheets, which are connected to an external high-voltage driving circuit to provide a uniform electric field for the crystal.

[0010] Preferably, the inner side of the front aperture three is nested with an extinction inner sleeve, the inner side of the rear aperture three is nested with an extinction bushing three, the mid-infrared electro-optic switch is a cadmium telluride electro-optic crystal, and oxygen-free copper gold-plated electrode sheets are provided on the two light-transmitting sides of the mid-infrared electro-optic switch. The oxygen-free copper gold-plated electrode sheets are connected to an external high-voltage driving circuit to provide a uniform electric field for the crystal.

[0011] Preferably, the blue laser module, near-infrared laser module, and mid-infrared laser module are respectively provided with laser fiber core one, laser fiber core two, and laser fiber core three, which are used to provide incident laser light sources in the blue, near-infrared, and mid-infrared bands, respectively. The three beam shaping boxes are respectively located at one end near the blue laser module, near-infrared laser module, and mid-infrared laser module as light inlets and at the other end as light outlets. Concave lenses and convex lenses are installed inside the beam shaping boxes. The concave lenses are located near the light inlets, and the convex lenses are located near the light outlets. The incident surface of the concave lens is a plane, and the exit surface is a concave surface. The incident surface of the convex lens is a convex surface, and the exit surface is a plane. The beam shaping boxes have two symmetrically distributed sliding grooves inside. A miniature electric push rod is fixedly installed inside the sliding groove. The output end of the miniature electric push rod is fixedly connected to a slider. The convex lens is fixedly connected between the two sliders.

[0012] Preferably, the dichroic mirror has two pairs of high blue light transmittance and high near-infrared reflectance, and one pair of dichroic mirrors has high blue light and near-infrared transmittance and high mid-infrared reflectance.

[0013] Preferably, the right end of the beam combiner box is connected to a two-dimensional scanner, the lower end of the two-dimensional scanner is equipped with a flat-field focusing lens, the left end of the two-dimensional scanner has a through-hole laser inlet, the lower end of the two-dimensional scanner has a through-hole laser outlet, a color difference correction cemented doublet lens is fixedly connected inside the two-dimensional scanner, the color difference correction cemented doublet lens is coaxially arranged with the laser inlet, a fixing frame one and a fixing frame two are fixedly connected inside the two-dimensional scanner, and a rotatable and adjustable reflector one and a reflector two are respectively arranged inside the fixing frame one and the fixing frame two, respectively. A stepper motor is provided on one side of the fixing frame one and the fixing frame two to drive the reflector one and the reflector two to rotate.

[0014] Preferably, the left end of the two-dimensional scanner is fixedly connected to two symmetrically distributed connecting frames. The left end of the connecting frame is provided with an adjustment groove, and the adjusting frame is slidably connected inside the adjustment groove. The lower end of the adjusting frame is fixedly connected to an air knife. The left ends of both the connecting frame and the adjusting frame are provided with connecting holes for installing bolts to lock the position of the adjusting frame. The rear end of the two-dimensional scanner is provided with a mounting flange for docking with an external drive device.

[0015] Specifically, the front aperture 401 is an annular aperture, and the inner extinction thread 4011 adopts a fine thread structure, which can absorb stray light and stray light in the incident laser, and prevent stray light from entering subsequent optical components and affecting beam quality. The surface of the extinction thread 4011 is blackened to further improve the stray light absorption efficiency and ensure the purity of the incident blue light.

[0016] Furthermore, the blue light collimating lens group 402 includes a crown glass positive lens 4021 and a flint glass negative lens 4022. The crown glass positive lens 4021 and the flint glass negative lens 4022 are arranged sequentially along the blue light laser emission direction. The crown glass positive lens 4021 and the flint glass negative lens 4022 are bonded together without gaps by optical epoxy adhesive to form an integrated bonding surface. The cross-section of the crown glass positive lens 4021 along the optical axis is biconvex, and both optical surfaces are spherical. The radius of curvature of the incident surface is greater than the radius of curvature of the bonding surface. The exit surface of the flint glass negative lens 4022 is a plane, and the incident surface is a concave spherical surface, which has the same absolute value as the radius of curvature of the bonding surface of the crown glass positive lens 4021. The two spherical surfaces are tightly bonded together.

[0017] Specifically, the blue light collimating lens group 402 adopts a crown glass and flint glass cemented structure to eliminate chromatic aberration and spherical aberration of blue light and achieve precise collimation. Crown glass is a low-dispersion material, and the positive lens made of it is responsible for focusing the laser. Flint glass is a high-dispersion material, and the negative lens made of it is responsible for correcting chromatic aberration. The two are bonded together seamlessly with optical epoxy adhesive. The integrated design can reduce reflection loss between lenses and improve light transmittance. The radius of curvature of the convex surface on the incident side of the crown glass positive lens 4021 is greater than the radius of curvature of the cemented surface, which can achieve initial gentle focusing of the laser and avoid excessive beam focusing that leads to local energy concentration.

[0018] Furthermore, the rear aperture 403 is internally nested with an matting bushing 4031.

[0019] Specifically, the rear aperture 403 is used to constrain the aperture of the blue light beam, and the nested extinction bushing 4031 can absorb the diffraction stray light at the edge of the beam, further improving the uniformity of the beam and preventing edge stray light from affecting the welding accuracy.

[0020] Furthermore, the blue photoelectric switch 404 is a KDP electro-optic crystal. The two light-transmitting sides of the blue photoelectric switch 404 are provided with oxygen-free copper gold-plated electrode sheets, which are connected to an external high-voltage driving circuit to provide a uniform electric field for the crystal.

[0021] Specifically, the 404 blue light optical switch is an electrically controlled on / off component of the blue light path. The oxygen-free copper gold-plated electrode has excellent conductivity and oxidation resistance, and can provide a uniform electric field to the crystal. The electric field strength is controlled by an external high-voltage drive circuit to achieve rapid switching between light transmission and extinction of the crystal, thereby controlling the on / off of the blue light path. It is suitable for the collaborative welding requirements of multi-wavelength lasers. It can be used for blue light welding alone or in conjunction with other wavelength lasers.

[0022] Referring to Figure 4, the near-infrared collimator 6 is provided with a front aperture 601, a near-infrared collimating lens group 602, a rear aperture 603, and a near-infrared electro-optic switch 604 from top to bottom. These are used to filter out incident stray light, collimate and shape the near-infrared laser beam, constrain edge diffraction stray light, and electrically control the on / off state of the optical path.

[0023] Furthermore, a light trap structure 6011 is nested inside the front aperture 601.

[0024] Specifically, the light trap structure 6011 inside the front aperture 601 is a conical structure, which can introduce incident stray light and stray light into the trap and filter out stray light in the near-infrared laser through multiple reflections and absorptions, so as to avoid stray light interfering with subsequent collimation and beam combining and ensure laser energy concentration.

[0025] Furthermore, the near-infrared collimating lens group 602 includes a cylindrical lens mount, a fused silica meniscus lens 6021, and a fused silica plano-convex lens 6022. The cylindrical lens mount is fixedly connected to the inside of the near-infrared collimator 6. The fused silica meniscus lens 6021 and the fused silica plano-convex lens 6022 are both installed inside the cylindrical lens mount and arranged sequentially along the near-infrared laser emission direction. The incident surface of the fused silica meniscus lens 6021 is concave and the exit surface is convex. The incident surface of the fused silica plano-convex lens 6022 is convex and the exit surface is planar. An air gap 6023 is formed between the fused silica meniscus lens 6021 and the fused silica plano-convex lens 6022.

[0026] Specifically, the cylindrical mount is used to fix the two lenses, ensuring lens coaxiality and preventing beam deviation. The fused silica meniscus lens 6021 is responsible for initial laser focusing, and the fused silica plano-convex lens 6022 is responsible for further collimation. The air gap 6023 between the two can reduce reflection loss between the lenses, while correcting spherical aberration and chromatic aberration, ensuring the parallelism of the near-infrared laser after collimation, and meeting the beam requirements of deep penetration welding.

[0027] Furthermore, an matting bushing 6031 is nested inside the rear aperture 603.

[0028] Specifically, the function of the rear aperture 603 and the extinction bushing 6031 is the same as that of the rear aperture of the blue light collimator 4, which is used to constrain the beam aperture, absorb edge diffraction stray light, and ensure the uniformity of the near-infrared beam.

[0029] Furthermore, the near-infrared electro-optic switch 604 is a lithium niobate electro-optic crystal. Oxygen-free copper gold-plated electrode sheets are provided on the two light-transmitting sides of the near-infrared electro-optic switch 604. The oxygen-free copper gold-plated electrode sheets are connected to an external high-voltage driving circuit to provide a uniform electric field for the crystal.

[0030] Specifically, the near-infrared electro-optic switch 604 uses a lithium niobate electro-optic crystal, which is compatible with the near-infrared band. It realizes the switching of the near-infrared optical path through electronic control. It can be used to turn on near-infrared welding alone, or it can be used in conjunction with blue light and mid-infrared lasers to flexibly adapt to different welding scenarios.

[0031] Referring to Figure 5, the interior of the mid-infrared collimator 8 is provided with, from bottom to top, a front aperture 801, a zinc selenide meniscus collimating lens 802, a rear aperture 803, and a mid-infrared electro-optic switch 804, which are used to perform electrical control and regulation of the mid-infrared laser beam in sequence for incident stray light suppression, collimation and shaping, beam aperture constraint, and optical path on / off.

[0032] Furthermore, an extinction inner sleeve 8011 is nested inside the front aperture 3 801, and an extinction bushing 3 8031 ​​is nested inside the rear aperture 3 803. The mid-infrared electro-optic switch 804 is a cadmium telluride electro-optic crystal. Oxygen-free copper gold-plated electrode sheets are provided on the two light-transmitting sides of the mid-infrared electro-optic switch 804. The oxygen-free copper gold-plated electrode sheets are connected to the external high-voltage driving circuit to provide a uniform electric field for the crystal.

[0033] Specifically, the matting inner sleeve 8011 of the front aperture 3 (801) and the matting bushing 3 (8031) of the rear aperture 3 (803) are both made of high-temperature resistant and high-absorption materials, which can effectively suppress incident stray light and edge stray light of mid-infrared laser, avoid the excessive heat effect of stray light, and protect the heat-sensitive materials. The aperture diameter is adapted to the characteristics of mid-infrared beams to ensure uniform beam energy distribution. The zinc selenide material has excellent mid-infrared transmittance and good thermal stability, which can avoid lens deformation caused by the thermal effect of mid-infrared laser. The meniscus structure design... It can simultaneously achieve beam collimation and chromatic aberration correction, ensuring the parallelism of the mid-infrared laser after collimation, while reducing beam distortion, making the laser energy evenly distributed, and avoiding local overheating that could damage the material. The mid-infrared electro-optic switch 804 uses a cadmium telluride electro-optic crystal adapted to the mid-infrared band. It realizes the on / off of the mid-infrared optical path through electronic control switching, adapting to the precise control of welding heat-sensitive materials. It can be used to start mid-infrared welding alone, or it can be used in conjunction with two other laser bands to achieve multi-wavelength composite welding, balancing welding efficiency and material protection.

[0034] Referring to Figure 6, the three beam shaping boxes 3 have light inlets 301 at one end near the blue laser module 5, near-infrared laser module 7, and mid-infrared laser module 9, and light outlets 302 at the other end. Concave lenses 303 and convex lenses 307 are installed inside the beam shaping boxes 3. The concave lens 303 is positioned near the light inlet 301, and the convex lens 307 is positioned near the light outlet 302. The incident surface of the concave lens 303 is flat, and the exit surface is concave. The incident surface of the convex lens 307 is convex, and the exit surface is flat. Two symmetrically distributed sliding grooves 304 are opened inside the beam shaping boxes 3. A miniature electric push rod 305 is fixedly installed inside the sliding groove 304. A slider 306 is fixedly connected to the output end of the miniature electric push rod 305. The convex lens 307 is fixedly connected between the two sliders 306.

[0035] Specifically, the beam shaping box 3 is used to perform secondary shaping on the collimated laser beam, adjusting the beam divergence angle and spot size. The concave lens 303 is responsible for diverging the laser beam, and the convex lens 307 is responsible for converging the laser beam. The two work together to adjust the divergence angle and spot size of the laser beam. The miniature electric push rod 305 can drive the slider 306 to slide along the slide groove 304, thereby adjusting the position of the convex lens 307 and realizing the adjustment of beam shaping parameters to adapt to the requirements of different welding scenarios for spot size and divergence angle.

[0036] Referring to Figure 7, dichroic mirror 201 has high transmittance for blue light and high reflectivity for near-infrared light, while dichroic mirror 101 has high transmittance for both blue light and near-infrared light and high reflectivity for mid-infrared light.

[0037] Specifically, the blue laser is collimated by the blue collimator 4 and shaped by the corresponding beam shaping box 3, then enters from the left end of the beam combiner 2. The dichroic mirror 201 has high transmittance for blue light, allowing it to pass directly through and propagate towards the beam combiner 1. The near-infrared laser is collimated by the near-infrared collimator 6 and shaped by the corresponding beam shaping box 3, then enters from the top end of the beam combiner 2. The dichroic mirror 201 has high reflectivity for near-infrared light, allowing it to pass through and propagate towards the beam combiner 1. The mid-infrared laser is coaxial with the blue laser and transmitted together in the direction of the beam combiner box 1. After being collimated by the mid-infrared collimator 8 and shaped by the corresponding beam shaping box 3, the mid-infrared laser enters from the lower end of the beam combiner box 1. The dichroic mirror 101 has high transmittance for blue and near-infrared light and high reflectivity for mid-infrared light. After being reflected by the dichroic mirror 101, the mid-infrared laser is coaxial with the blue and near-infrared lasers, and finally forms a multi-wavelength composite laser beam, which is output from the right end of the beam combiner box 1 and enters the two-dimensional scanner 10.

[0038] It should be noted that both dichroic mirror 101 and dichroic mirror 201 adopt high-precision optical coating technology, with accurate transmission and reflection characteristics, which can ensure efficient beam combining of lasers of different wavelengths and reduce energy loss. Both beam combining boxes 1 and 2 are sealed structures with internal extinction treatment to prevent stray light from being generated by laser reflection inside the box, and to ensure the purity and coaxiality of the laser beam after beam combining.

[0039] Referring to Figures 1 and 8, a 2D scanner 10 is connected to the right end of the beam combiner 1. A flat-field focusing lens 11 is installed at the lower end of the 2D scanner 10. A laser inlet 1001 is provided through the left end of the 2D scanner 10. A laser outlet 1002 is provided through the lower end of the 2D scanner 10. A color difference correction cemented doublet lens 1003 is fixedly connected inside the 2D scanner 10. The color difference correction cemented doublet lens 1003 is coaxially arranged with the laser inlet 1001. A first fixing frame 1004 and a second fixing frame 1006 are fixedly connected inside the 2D scanner 10. Rotatable and adjustable reflectors 1005 and 1007 are respectively installed inside the first fixing frame 1004 and the second fixing frame 1006. A stepper motor is provided on one side of both the first fixing frame 1004 and the second fixing frame 1006 to drive the first reflecting mirror 1005 and the second reflecting mirror 1007 to rotate.

[0040] Specifically, the laser inlet 1001 of the 2D scanner 10 is connected to the beam combiner box 1 to receive the coaxially combined laser beam. The chromatic aberration correction double-cemented lens 1003 is used to correct the chromatic aberration of multi-wavelength lasers, ensuring that different wavelength lasers are focused on the same point, avoiding focus shift due to chromatic aberration, and improving welding accuracy. The lens adopts a double-cemented structure, which can effectively eliminate chromatic aberration and spherical aberration of multi-wavelength lasers, ensuring the clarity and uniformity of the focused spot. The first reflector 1005 and the second reflector 1007 are high-precision reflectors, which are installed in the first fixture 1004 and the second fixture 1006 respectively, and are driven to rotate by a stepper motor. The two reflectors cooperate with each other to realize the scanning adjustment of the laser beam in the X and Y two-dimensional directions, thereby realizing the flexible switching of the welding position, adapting to the needs of complex welds and large-area welding, without moving the welding workpiece, improving welding efficiency and accuracy. The flat field focusing lens 11 is installed at the laser outlet 1002 of the 2D scanner 10 to accurately focus the multi-wavelength laser after 2D scanning onto the surface of the welding workpiece.

[0041] It should be noted that the stepper motor is equipped with an encoder to achieve precise angle adjustment. The chromatic aberration correcting double-bonded lens 1003 is made of a low-dispersion crown glass lens and a high-dispersion flint glass lens, which are tightly bonded together with optical epoxy to form an integrated bonding surface. The absolute values ​​of the curvature radii of the bonding surfaces of the two lenses are equal. The crown glass lens has a biconvex structure and is responsible for initially focusing multi-wavelength composite lasers, while the flint glass lens has a biconcave structure and is responsible for specifically correcting the dispersion deviation of lasers of different wavelengths. The two work together to effectively cancel the chromatic aberration of three different wavelength lasers: blue light, near-infrared, and mid-infrared. At the same time, they help correct spherical aberration, ensuring that the three laser beams are focused on the same point after passing through the lens, avoiding focusing shift caused by wavelength differences, and providing a guarantee for subsequent precise welding.

[0042] Referring to Figure 2, two symmetrically distributed connecting frames 12 are fixedly connected to the left end of the 2D scanner 10. An adjustment groove 13 is provided at the left end of the connecting frame 12. An adjustment frame 14 is slidably connected inside the adjustment groove 13. An air knife 16 is fixedly connected to the lower end of the adjustment frame 14. A connecting hole 15 is provided through the left end of both the connecting frame 12 and the adjustment frame 14 for installing bolts to lock the position of the adjustment frame 14. A mounting flange 17 is provided at the rear end of the 2D scanner 10 for docking with an external drive device.

[0043] Specifically, the air knife 16 is used for air cooling during welding. The adjusting frame 14 can slide along the adjusting groove 13 of the connecting frame 12 to adjust the position of the air knife 16. After adjustment, the adjusting frame 14 is locked by bolts passing through the connecting hole 15 to ensure the stability of the air knife 16 position. The mounting flange 17 is the docking part between the device and external driving equipment, such as a robotic arm or mobile platform. Through the mounting flange 17, the device can be fixed to the external driving equipment to realize three-dimensional adjustment of the welding position and improve the versatility and flexibility of the device.

[0044] Working Principle: When this multi-wavelength composite laser welding device is working, the blue laser module 5, near-infrared laser module 7, and mid-infrared laser module 9 first generate three laser beams: 450-480nm blue light, 1064-1080nm near-infrared light, and 1550-1600nm mid-infrared light, respectively, through the internal laser fiber cores 501, 701, and 901. The three laser beams enter the corresponding blue collimator 4, near-infrared collimator 6, and mid-infrared collimator 8, respectively. The blue laser beam passes through the front aperture 401 with an extinction thread 4011, the cemented blue collimating lens group 402, the rear aperture 403 with an extinction bushing 4031, and the blue laser beam. Switch 404 performs stray light suppression, collimation and shaping, and optical path on / off control. Near-infrared laser light passes through a pre-aperture 601 with a conical light trap structure 6011, a near-infrared collimating lens group 602 with an air gap 6023, a rear-aperture 603 with an extinction bushing 6031, and a near-infrared electro-optic switch 604 to achieve stray light filtering, collimation correction, and optical path adjustment. Mid-infrared laser light passes through a pre-aperture 801 with an extinction inner bushing 8011, a zinc selenide meniscus collimating lens 802, a rear-aperture 803 with an extinction bushing 8031, and a mid-infrared electro-optic switch 804 to achieve stray light suppression, collimation and shaping, and optical path on / off control. The three collimated laser beams then enter the beam shaping box 3, and... The beam divergence angle and spot size are adjusted by the internal concave lens 303 and the convergence of the convex lens 307. A miniature electric push rod 305 drives a slider 306 to slide along a groove 304, thus achieving secondary shaping and control of the beam divergence angle and spot size. The shaped blue laser enters from the left end of beam combiner box 2 and passes through dichroic mirror 201. Near-infrared laser enters from the upper end of beam combiner box 2 and is reflected by dichroic mirror 201, becoming coaxial with the blue laser. Mid-infrared laser enters from the lower end of beam combiner box 1 and is reflected by dichroic mirror 101, becoming coaxial with the former two. Finally, a multi-wavelength composite laser is formed and output from the right end of beam combiner box 1. After entering the 2D scanner 10, the composite laser first passes through a color difference corrected double cemented lens 100. 3. Eliminate multi-wavelength chromatic aberration and spherical aberration, and then drive the reflector 1005 and reflector 2007 with an encoder to achieve X and Y two-dimensional scanning adjustment. Finally, the flat field focusing lens 11 is used to accurately focus on the surface of the workpiece to complete the welding operation. During the welding process, the air knife 16 is simultaneously cooled by air. Its position can be adjusted by sliding the adjustment frame 14 in the adjustment groove 13 of the connecting frame 12 and locked by bolts passing through the connecting hole 15. The device can also be connected to external robotic arms or mobile platforms and other driving equipment through the mounting flange 17 to achieve three-dimensional adjustment of the welding position, so as to flexibly adapt to the precision welding needs of different scenarios such as thin metals, medium and thick metals, heat-sensitive materials and dissimilar materials.

[0045] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

[0046] Compared with the prior art, the beneficial effects of this invention are as follows: This solution proposes a multi-wavelength composite laser welding device, which adopts a design of three independent laser modules with blue light, near-infrared and mid-infrared wavelengths, and is equipped with a dedicated electro-optic switch for each wavelength optical path. It can achieve flexible switching of single-wavelength independent light output, dual-wavelength coordinated light output or three-wavelength synchronous light output through an external high-voltage drive circuit. Furthermore, the light output sequence and conduction time of each wavelength can be adjusted through the electro-optic switch. The optical path parameters can be dynamically adjusted according to the needs of different stages of the welding process, so as to achieve fine control of the welding process and improve the consistency of welding quality under complex working conditions.

[0047] This solution configures independent beam shaping boxes for the blue, near-infrared, and mid-infrared lasers. Each beam shaping box has a convex lens that slides along a groove via a miniature electric push rod, allowing for individual adjustment of the spot size and divergence angle parameters of the corresponding wavelength laser. This enables independent control of the focusing depth for each wavelength, allowing for customized control of the spot shape and focusing depth for different application scenarios. For example, blue light is suitable for precision welding of thin materials requiring a small spot size, near-infrared light is suitable for deep-penetration welding of thick materials requiring a long focusing depth, and mid-infrared light is suitable for welding of thermosensitive materials requiring a uniform spot size. This solution can simultaneously meet the differentiated welding needs of thin metals, medium-thick metals, thermosensitive materials, and dissimilar materials, improving the adaptability of the device to different welding processes.

[0048] In this invention, the blue collimator uses a front aperture with an extinction thread, the near-infrared collimator uses a front aperture with a light trap, and the mid-infrared collimator uses a front aperture with a high-temperature resistant extinction inner sleeve. All three collimators are equipped with a rear aperture with an extinction bushing, which can absorb incident stray light from the source and filter out edge diffraction stray light, preventing stray light from entering subsequent optical components and causing interference, and effectively reducing the impact of stray light on beam quality during collimation.

[0049] This invention uses dual chromatic aberration correction—single-wavelength collimation correction and multi-wavelength beam combining correction—to offset the dispersion deviations of blue light, near-infrared, and mid-infrared, thereby reducing the focusing offset and effectively eliminating minor errors in the welding process. Attached Figure Description

[0050] Figure 1 is a three-dimensional structural schematic diagram of the present invention; Figure 2 is a three-dimensional structural schematic diagram of the present invention from another perspective; Figure 3 is a structural schematic diagram of the interior of the blue laser collimator in the present invention; Figure 4 is a structural schematic diagram of the interior of the near-infrared laser collimator in the present invention; Figure 5 is a structural schematic diagram of the interior of the mid-infrared laser collimator in the present invention; Figure 6 is a structural schematic diagram of the interior of the beam shaping box in the present invention; Figure 7 is a connection schematic diagram of beam combining box one and beam combining box two in the present invention; Figure 8 is a structural schematic diagram of the two-dimensional scanner in the present invention.

[0051] The diagram is labeled as follows: 1. Beam combiner box one; 101. Dichroic mirror one; 2. Beam combiner box two; 201. Dichroic mirror two; 3. Beam shaping box; 301. Light inlet; 302. Light outlet; 303. Concave lens; 304. Slide rail; 305. Miniature electric actuator; 306. Slider; 307. Convex lens; 4. Blue light collimator; 401. Front aperture one; 4011. Extinction thread; 402. Blue light collimating lens group; 40 21. Crown glass positive lens; 4022. Flint glass negative lens; 403. Rear aperture 1; 4031. Extinction bushing 1; 404. Blue light photoelectric switch; 5. Blue laser module; 501. Laser fiber core 1; 6. Near-infrared collimator; 601. Front aperture 2; 6011. Light trap structure; 602. Near-infrared collimating lens group; 6021. Fused silica meniscus positive lens; 6022. Fused silica plano-convex positive lens; 6023, Air gap; 603, Rear aperture II; 6031, Extinction bushing II; 604, Near-infrared electro-optic switch; 7, Near-infrared laser module; 701, Laser fiber core II; 8, Mid-infrared collimator; 801, Front aperture III; 8011, Extinction inner sleeve; 802, Zinc selenide meniscus collimating lens; 803, Rear aperture III; 8031, Extinction bushing III; 804, Mid-infrared electro-optic switch; 9, Mid-infrared laser module Block; 901, Laser fiber core three; 10, 2D scanner; 1001, Laser inlet; 1002, Laser outlet; 1003, Chromatic aberration corrected cemented doublet lens; 1004, Mounting bracket one; 1005, Reflector one; 1006, Mounting bracket two; 1007, Reflector two; 11, Planar focusing lens; 12, Connecting bracket; 13, Adjustment slot; 14, Adjustment bracket; 15, Connecting hole; 16, Air knife; 17, Mounting flange. Detailed Implementation

[0052] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0053] Referring to Figures 1 and 3-7, a multi-wavelength composite laser welding device includes a beam combiner box 1. A beam combiner box 2 is fixedly connected to the left side of beam combiner box 1. Dichroic mirrors 101 and 201 are respectively installed inside beam combiner box 1 and beam combiner box 2 for spatial coaxial beam combining of blue light, near-infrared, and mid-infrared lasers. Beam shaping boxes 3 are fixedly connected to the upper and left ends of beam combiner box 2 and the lower end of beam combiner box 1. The other ends of the three beam shaping boxes 3 are respectively fixedly connected to... Blue light collimator 4, near-infrared collimator 6, and mid-infrared collimator 8 are provided. The other ends of blue light collimator 4, near-infrared collimator 6, and mid-infrared collimator 8 are sequentially fixedly connected to blue light laser module 5, near-infrared laser module 7, and mid-infrared laser module 9. Inside blue light laser module 5, near-infrared laser module 7, and mid-infrared laser module 9, laser fiber core 1 501, laser fiber core 2 701, and laser fiber core 3 901 are respectively provided to provide incident laser sources in the blue light, near-infrared, and mid-infrared bands.

[0054] Specifically, the blue laser has a wavelength of 450-480nm, moderate penetration, and high focusing accuracy, making it suitable for precision welding of thin metal and non-metal materials and reducing the heat-affected zone. The near-infrared laser has a wavelength of 1064-1080nm, strong penetration, and concentrated energy, making it suitable for deep penetration welding of medium-thick metal materials. The mid-infrared laser has a wavelength of 1550-1600nm, with a mild thermal effect, making it suitable for welding heat-sensitive materials and dissimilar materials. The three laser modules with different wavelengths can provide laser sources that can be adapted to different welding scenarios. The beam shaping box 3 is used to perform secondary shaping on the collimated laser to ensure that the beam cross-section is uniform and the divergence angle is controllable.

[0055] Referring to Figure 3, the blue light collimator 4 is provided with a front aperture 401, a blue light collimating lens group 402, a rear aperture 403, and a blue light photoelectric switch 404 from left to right. These are used for electronically controlling the suppression of incident stray light, collimation and shaping, edge stray light constraint, and optical path switching of the blue laser beam.

[0056] Furthermore, the inner side of the front aperture 401 is machined with a matte thread 4011.

Claims

1. A multi-wavelength composite laser welding device, characterized in that, The system includes a beam combiner box 1 (1), to which a beam combiner box 2 (2) is fixedly connected. Dichroic mirrors 1 (101) and 2 (201) are respectively installed inside beam combiner box 1 (1) and beam combiner box 2 (2) for spatial coaxial beam combining of blue light, near-infrared, and mid-infrared lasers. Beam shaping boxes (3) are fixedly connected to the upper and left ends of beam combiner box 2 (2) and the lower end of beam combiner box 1 (1). The three beam shaping boxes... The other end of the shape box (3) is fixedly connected to a blue collimator (4), a near-infrared collimator (6), and a mid-infrared collimator (8). The other ends of the blue collimator (4), the near-infrared collimator (6), and the mid-infrared collimator (8) are fixedly connected to a blue laser module (5), a near-infrared laser module (7), and a mid-infrared laser module (9). The interior of the blue collimator (4) is arranged from left to right with a front aperture 1 (401), a blue collimating lens group (402), a rear aperture 1 (403), and a blue electro-optic switch (404), which are used for the electronic control switching of incident stray light suppression, collimation shaping, edge stray light constraint, and optical path on / off of the blue laser beam, respectively. The interior of the near-infrared collimator (6) is arranged from top to bottom with a front aperture 2 (601), a near-infrared collimating lens group (602), a rear aperture 2 (603), and a near-infrared electro-optic switch (604), which are used for the near-infrared laser beam to suppress incident stray light, collimate and shape, constrain edge stray light, and switch the optical path on / off, respectively. The beam is subjected to incident stray light filtering, collimation and shaping, edge diffraction stray light constraint, and electronic control of optical path opening and closing. The interior of the mid-infrared collimator (8) is provided with a front aperture three (801), a zinc selenide meniscus collimating lens (802), a rear aperture three (803) and a mid-infrared electro-optic switch (804) from bottom to top, which are used to perform incident stray light suppression, collimation and shaping, beam aperture constraint and optical path opening and closing electronic control of the mid-infrared laser beam in sequence.

2. The multi-wavelength composite laser welding device according to claim 1, characterized in that: The blue light collimating lens group (402) includes a crown glass positive lens (4021) and a flint glass negative lens (4022). The crown glass positive lens (4021) and the flint glass negative lens (4022) are arranged sequentially along the blue light laser emission direction. The crown glass positive lens (4021) and the flint glass negative lens (4022) are bonded together without gaps by optical epoxy adhesive to form an integrated bonding surface. The cross section of the crown glass positive lens (4021) along the optical axis is biconvex, and both optical surfaces are spherical. The radius of curvature of the incident surface is greater than the radius of curvature of the bonding surface. The exit surface of the flint glass negative lens (4022) is a plane, and the incident surface is a concave spherical surface. The absolute value of the radius of curvature of the bonding surface of the crown glass positive lens (4021) is equal to that of the bonding surface of the crown glass positive lens (4021). The two spherical surfaces are tightly bonded together.

3. The multi-wavelength composite laser welding device according to claim 1, characterized in that: The inner side of the front aperture (401) is machined with a matting thread (4011), and the inner side of the rear aperture (403) is nested with a matting bushing (4031). The blue photoelectric switch (404) is a KDP electro-optic crystal. The two light-transmitting sides of the blue photoelectric switch (404) are provided with oxygen-free copper gold-plated electrode sheets. The oxygen-free copper gold-plated electrode sheets are connected to the external high-voltage driving circuit to provide a uniform electric field for the crystal.

4. The multi-wavelength composite laser welding device according to claim 1, characterized in that: The near-infrared collimating lens group (602) includes a cylindrical lens mount, a fused silica meniscus lens (6021), and a fused silica plano-convex lens (6022). The cylindrical lens mount is fixedly connected to the inside of the near-infrared collimator (6). The fused silica meniscus lens (6021) and the fused silica plano-convex lens (6022) are both installed inside the cylindrical lens mount and arranged sequentially along the near-infrared laser emission direction. The incident surface of the fused silica meniscus lens (6021) is concave and the exit surface is convex. The incident surface of the fused silica plano-convex lens (6022) is convex and the exit surface is planar. An air gap (6023) is formed between the fused silica meniscus lens (6021) and the fused silica plano-convex lens (6022).

5. The multi-wavelength composite laser welding device according to claim 1, characterized in that: The inner side of the second front aperture (601) is nested with a light trap structure (6011), and the inner side of the second rear aperture (603) is nested with an extinction bushing (6031). The near-infrared electro-optic switch (604) is a lithium niobate electro-optic crystal. The two light-transmitting sides of the near-infrared electro-optic switch (604) are provided with oxygen-free copper gold-plated electrode sheets. The oxygen-free copper gold-plated electrode sheets are connected to an external high-voltage driving circuit to provide a uniform electric field for the crystal.

6. The multi-wavelength composite laser welding device according to claim 1, characterized in that: The inner side of the front aperture three (801) is nested with an extinction inner sleeve (8011), and the inner side of the rear aperture three (803) is nested with an extinction bushing three (8031). The mid-infrared electro-optic switch (804) is a cadmium telluride electro-optic crystal. The two light-transmitting sides of the mid-infrared electro-optic switch (804) are provided with oxygen-free copper gold-plated electrode sheets. The oxygen-free copper gold-plated electrode sheets are connected to the external high-voltage driving circuit to provide a uniform electric field for the crystal.

7. The multi-wavelength composite laser welding device according to claim 1, characterized in that: The blue laser module (5), near-infrared laser module (7), and mid-infrared laser module (9) are respectively equipped with laser fiber core one (501), laser fiber core two (701), and laser fiber core three (901) to provide incident laser sources in the blue, near-infrared, and mid-infrared bands, respectively. The three beam shaping boxes (3) are respectively located near the blue laser module (5), near-infrared laser module (7), and mid-infrared laser module (9) with one end as the light inlet (301) and the other end as the light outlet (302). A concave lens (303) and a convex lens (302) are installed on the inner side of the beam shaping box (3). 7) A concave lens (303) is positioned near the light inlet (301), and a convex lens (307) is positioned near the light outlet (302). The incident surface of the concave lens (303) is a plane, and the exit surface is a concave surface. The incident surface of the convex lens (307) is a convex surface, and the exit surface is a plane. Two symmetrically distributed sliding grooves (304) are opened inside the beam shaping box (3). A miniature electric push rod (305) is fixedly installed inside the sliding groove (304). A slider (306) is fixedly connected to the output end of the miniature electric push rod (305). The convex lens (307) is fixedly connected between the two sliders (306).

8. The multi-wavelength composite laser welding device according to claim 1, characterized in that: The dichroic mirror 2 (201) is highly transparent to blue light and highly reflective to near-infrared light, while the dichroic mirror 1 (101) is highly transparent to both blue light and near-infrared light and highly reflective to mid-infrared light.

9. The multi-wavelength composite laser welding device according to claim 1, characterized in that: The right end of the beam combiner box (1) is connected to a two-dimensional scanner (10). A flat-field focusing lens (11) is installed at the lower end of the two-dimensional scanner (10). A laser inlet (1001) is opened through the left end of the two-dimensional scanner (10). A laser outlet (1002) is opened through the lower end of the two-dimensional scanner (10). A color difference correction cemented doublet lens (1003) is fixedly connected inside the two-dimensional scanner (10). The color difference correction cemented doublet lens (1003) and the laser inlet (1001) are connected through the two-dimensional scanner (1002). The two-dimensional scanner (10) is coaxially connected to a fixed frame 1 (1004) and a fixed frame 2 (1006). The fixed frame 1 (1004) and the fixed frame 2 (1006) are respectively equipped with a rotatable and adjustable reflector 1 (1005) and a reflector 2 (1007). A stepper motor is provided on one side of the fixed frame 1 (1004) and the fixed frame 2 (1006) to drive the reflector 1 (1005) and the reflector 2 (1007) to rotate.

10. A multi-wavelength composite laser welding device according to claim 9, characterized in that: The left end of the two-dimensional scanner (10) is fixedly connected to two symmetrically distributed connecting frames (12). The left end of the connecting frame (12) is provided with an adjustment groove (13). An adjustment frame (14) is slidably connected inside the adjustment groove (13). An air knife (16) is fixedly connected to the lower end of the adjustment frame (14). The left ends of both the connecting frame (12) and the adjustment frame (14) are provided with a connecting hole (15) for installing bolts to lock the position of the adjustment frame (14). The rear end of the two-dimensional scanner (10) is provided with a mounting flange (17) for docking with an external drive device.

Images