Heterogeneous metal laser welding device

Abstract

The invention relates to the technical field of laser welding, in particular to a dissimilar metal laser welding device which comprises a base, and a welding area is arranged at the top of the base. According to the dissimilar metal laser welding device, through an intelligent airflow isolation system, a flexible baffle structure pressurized by a spring is adopted, and dynamic sealing is formed by automatically attaching to the surface of a workpiece in the welding process. A protective air curtain is built around a welding area, cooling airflow is allowed to pass through the peripheral area to achieve overall cooling, airflow disturbance directly blown to a welding seam can be effectively blocked, and a self-adaptive welding seam tracking mechanism is adopted; the whole protection frame is driven to deflect synchronously through contact friction force between the limiting pad and the workpiece. According to the mechanical tracking mechanism, the position of the baffle can be adjusted in real time without an additional sensor and a control system, so that a protection area accurately covers a welding seam path all the time. And the method is particularly suitable for the common irregular joint situation during dissimilar metal welding.

Description

Technical Field

[0001] The present invention relates to the technical field of laser welding, and particularly to a laser welding device for dissimilar metals. Background Technique

[0002] Laser welding of dissimilar metals is a key process to achieve complementary advantages of material properties and has important application value in fields such as aerospace and new energy vehicles. The core contradiction faced by this technology stems from the significant differences in melting point, thermal conductivity, coefficient of thermal expansion, etc. between dissimilar materials. These differences easily lead to problems such as metallurgical incompatibility and thermal stress concentration during the welding process, seriously affecting the joint quality and service performance.

[0003] Regarding the currently common technologies for laser welding of dissimilar metals, there are still the following deficiencies.

[0004] Insufficient dynamic protection: Traditional protection devices are difficult to adapt to complex weld trajectories, resulting in insufficient coverage of the shielding gas and the molten pool being easily contaminated by the atmosphere. Lag in real-time tracking: The response speed of existing tracking systems is insufficient, and it is difficult to ensure the precise alignment of the laser focus with the weld during high-speed welding. Imbalance in thermal management: The single-sided cooling method exacerbates the thermal gradient at the interface of dissimilar materials, inducing the formation of brittle phases and residual stress concentration.

[0005] In view of this, we propose a laser welding device for dissimilar metals. Summary of the Invention

[0006] The purpose of the present invention is to provide a laser welding device for dissimilar metals to solve the problems of insufficient dynamic protection, lag in real-time tracking, and imbalance in thermal management proposed in the above background technique. To achieve the above purpose, the present invention provides the following technical solution: A laser welding device for dissimilar metals, including a base, the top of the base is set as a welding area, and two first guide rails are fixedly arranged on the top of the base through columns. A second guide rail is arranged on the first guide rail, and the second guide rail moves horizontally along the first guide rail. A moving seat is arranged on the second guide rail, and the moving seat moves longitudinally along the second guide rail; A laser welding gun is slidably arranged on the moving seat in the vertical direction, and a rectangular frame is arranged on the laser welding gun. Two groups of blowers blowing downward are symmetrically arranged on the frame, and two baffles for blocking the air flow are symmetrically arranged at the bottom of the frame. A spring is arranged between the baffle and the frame, and the spring pushes the baffle to move downward onto the welded part.

[0007] Preferably, a ring base is rotatably connected to the tip of the laser welding torch. The frame is fixedly connected to the ring base, and the ring base is eccentrically connected to one end of the frame deviating from the middle position. A shrapnel is fixedly arranged at the bottom of the baffle, and the connection points of the shrapnel and the ring base are distributed oppositely. A limiting pad with frictional resistance is fixedly arranged at the contact end of the shrapnel and the welded part.

[0008] Preferably, a through hole is formed on the surface of the baffle, and a flap is rotatably connected in the through hole through a shaft rod. A through groove for the laser to pass through is formed on the surface of the flap. One end of the shaft rod is fixedly connected to a lower cam that drives the flap to deflect. A micro motor is fixedly arranged on the side of the baffle through a bracket, and an upper cam that intermittently pushes the lower cam is fixedly connected to the rotating shaft of the micro motor.

[0009] Preferably, a clamping groove is formed on the ring base, a clamping buckle is fixedly arranged on the frame, and the frame is fixed in the clamping groove through the cooperation of the clamping buckle and a screw. A notch for the clamping buckle to break away is also formed on the ring base.

[0010] Preferably, a replaceable high-temperature resistant backing plate is provided in the welding area. The surface of the backing plate is provided with positioning grooves matching the contour of the dissimilar metal welded part. The positioning grooves on the surface of the backing plate match the contour of the welded part, ensuring that the dissimilar metal welded part is closely attached, reducing welding misalignment. The backing plate can be quickly replaced to adapt to welded parts of different shapes / sizes, improving the versatility of the equipment. The high-temperature resistant backing plate isolates the high temperature of the molten pool, prevents the base from thermal deformation, extends the service life of the equipment, and replacing the backing plate can quickly clean the welding slag, reducing the downtime.

[0011] Preferably, the moving seat is integrated with a laser positioning module, which includes a CCD camera and a cross laser indicator. The CCD camera captures the position of the weld seam in real time, and the cross laser indicator provides visual assistance to ensure that the laser focus is accurately aligned with the junction of dissimilar metals. The welding path is corrected in real time through image feedback, reducing the scrap rate.

[0012] Preferably, the air outlet of the blower is in a tapered Venturi structure. A temperature sensor is embedded in the baffle. The tapered Venturi structure accelerates the air flow and enhances the local cooling effect. The embedded temperature sensor monitors the temperature of the welding area in real time to avoid weld cracks caused by uneven heat input (especially for dissimilar metals with large differences in thermal sensitivity).

[0013] Preferably, a quick-release protective gas nozzle is provided on the side of the frame. The angle of the nozzle can be adjusted through a universal joint. The universal joint adjusts the angle of the nozzle to ensure that the protective gas accurately covers the molten pool, adapting to different welding directions. The quick-release design facilitates cleaning the nozzle blockage or replacing the gas type (such as switching to inert gas for aluminum / steel dissimilar welding).

[0014] Preferably, an electromagnetic shielding layer is provided inside the base. The shielding layer is made of permalloy material, and the permalloy shielding layer blocks the high-frequency electromagnetic interference of the laser and ensures the signal stability of the control system (such as temperature sensors and positioning modules).

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: In the present invention, through the intelligent air flow isolation system: a flexible baffle structure with spring pressure is adopted to automatically fit the surface of the workpiece during the welding process to form a dynamic seal. Through the ingenious air flow guiding design, a protective air curtain is established around the welding area, which not only allows the cooling air flow to pass through the surrounding area to achieve overall cooling, but also effectively blocks the air flow disturbance directly blowing towards the weld seam.

[0016] In the present invention, through the adaptive weld seam tracking mechanism: an intelligent follow-up system based on the principle of friction drive. When the welding torch performs complex trajectory movements, the entire protection frame is synchronously deflected by the contact friction force between the limit pad and the workpiece. This mechanical tracking mechanism can adjust the position of the baffle in real time without additional sensors and control systems, so that the protection area always accurately covers the weld path. It is especially suitable for irregular joint situations commonly encountered in dissimilar metal welding.

[0017] In the present invention, through the dynamic alternating heat dissipation system: the innovative flap-type heat dissipation structure realizes periodic opening and closing actions through a cam mechanism, and creatively divides a single cooling area into two alternately working heat dissipation channels. This design not only ensures the continuous heat dissipation capacity, but also avoids the temperature gradient problem caused by traditional single-sided cooling. The system can automatically adjust the flap action frequency according to the welding heat input to achieve intelligent matching of the heat dissipation intensity and the welding process. Description of the Drawings

[0018] Figure 1 is a three-dimensional structure schematic diagram of the present invention; Figure 2 is of the present invention Figure 1 the enlarged view of part A in; Figure 3 is the structural schematic diagram of the ring seat, frame and baffle of the present invention Figure 1 ; Figure 4 is the structural schematic diagram of the ring seat, frame and baffle of the present invention Figure 2 ; Figure 5 is of the present invention Figure 4 the enlarged view of part B in; Figure 6 is the exploded view of the frame, baffle and flap of the present invention; Figure 7 is of the present invention Figure 6 the enlarged view of part C in; Figure 8This is a schematic structural diagram of the flap deflection state of the present invention.

[0019] In the figure: 1, base; 2, first guide rail; 3, second guide rail; 4, moving seat; 5, laser welding gun; 6, ring seat; 7, frame; 8, fan; 9, baffle; 10, spring; 11, flap; 12, through groove; 13, limit pad; 14, card slot; 15, notch; 16, buckle; 17, micro motor; 18, upper cam; 19, lower cam. Specific embodiments

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0021] Please refer to Figures 1 to 8 , the present invention provides a technical solution: a heterogeneous metal laser welding device, including a base 1, the top of the base 1 is set as a welding area, and two first guide rails 2 are fixedly arranged on the top of the base 1 through columns. A second guide rail 3 is arranged on the first guide rail 2, and the second guide rail 3 moves horizontally along the first guide rail 2. A moving seat 4 is arranged on the second guide rail 3, and the moving seat 4 moves longitudinally along the second guide rail 3.

[0022] A laser welding gun 5 is slidably arranged on the moving seat 4 in the vertical direction, and a rectangular frame 7 is arranged on the laser welding gun 5. Two groups of fans 8 that blow downward are symmetrically arranged on the frame 7, and two baffles 9 that block the air flow are symmetrically arranged at the bottom of the frame 7. A spring 10 is arranged between the baffle 9 and the frame 7, and the spring 10 pushes the baffle 9 downward to the weldment.

[0023] A ring seat 6 is rotatably connected to the tip of the laser welding gun 5. A card slot 14 is opened on the ring seat 6. A buckle 16 is fixedly arranged on the frame 7, and the frame 7 is fixed in the card slot 14 through the cooperation of the buckle 16 and a screw. A notch 15 for the buckle 16 to disengage is also opened on the ring seat 6.

[0024] The frame 7 is fixedly connected to the ring seat 6, and the ring seat 6 is eccentrically connected along one end of the frame 7 deviating from the middle position. A spring piece is fixedly arranged at the bottom of the baffle 9, and the connection points of the spring piece and the ring seat 6 are distributed oppositely. A limit pad 13 with frictional resistance is fixedly arranged at the contact end of the spring piece and the weldment.

[0025] The surface of the baffle 9 is provided with a through opening, and a flap 11 is rotatably connected in the through opening by a shaft rod. A through groove 12 for the laser to pass through is provided on the surface of the flap 11. One end of the shaft rod is fixedly connected with a lower cam 19 that drives the flap 11 to deflect. A micro motor 17 is fixedly arranged on the side edge of the baffle 9 through a bracket, and an upper cam 18 that intermittently pushes the lower cam 19 is fixedly connected to the rotating shaft of the micro motor 17.

[0026] ‌Example 1: Structure of the welding device‌ The laser welding device includes a cast iron base 1, and an array of T-shaped grooves with a spacing of 50 mm is provided on its surface.

[0027] The adjustable column is vertically fixed to the base 1 through a locking bolt, with an adjustment stroke of 200 mm and the precision controlled within the range of ±0.5 mm.

[0028] The motion system uses a cross roller guide to achieve X-direction movement with a stroke of 300 mm. The Y-direction slide is slidably connected to the X-direction guide through a linear slider, and mounting holes with a diameter of 8 mm are provided on the surface of the slide.

[0029] The servo motor drives a ball screw with a lead of 5 mm, and the repeat positioning accuracy reaches ±0.003 mm.

[0030] The laser welding torch 5 is connected to the slide through a quick-change flange, and the flange positioning pin is manufactured according to the g6 tolerance.

[0031] The floating buffer mechanism includes two linear bearings with an inner diameter of 12 mm, a preloaded spring with a spring constant of 8 N / mm ± 5%, and a displacement sensor with a range of ±10 mm and a resolution of 0.01 mm.

[0032] ‌Example 2: Dynamic air flow control system‌ The baffle 9 is made of a 3-mm-thick stainless steel plate, and the working surface is polished to a surface roughness Ra of no more than 0.8 μm.

[0033] A silicone rubber limit pad 13 with a Shore hardness of 60 HA is vulcanized and bonded to the bottom surface of the baffle 9, with a thickness of 2 mm.

[0034] The flap 11 mechanism performs timing control: when starting to act, it rotates the baffle 9 to a 20-degree angle in 0.8 ± 0.1 seconds, keeps it for 1.2 ± 0.2 seconds, and then completes the closing action in 2.0 ± 0.1 seconds.

[0035] The centrifugal fan 8 has a power of 550 W, and its air outlet is connected to a venturi tube with a throat diameter of 25 mm. The rotation speed of the fan 8 has a linear relationship with the air flow speed.

[0036] ‌Example 3: Welding process method‌ During operation, first place the dissimilar metal workpiece in the V-groove of the high-temperature resistant backing plate and apply a vacuum adsorption force of -0.08 MPa for fixation. Call the preset parameters according to the material combination: Copper-aluminum combination: Laser power 2.8 ± 0.2 kW, scanning speed 35 ± 5 mm / s, defocus amount +1.5 mm.

[0037] Titanium-steel combination: Laser power 3.6 ± 0.3 kW, scanning speed 25 ± 3 mm / s, defocus amount -0.8 mm.

[0038] In the dynamic control stage, when the temperature sensor detects that the temperature exceeds 350 °C, adjust the wind speed by increasing 0.05 m / s for each degree Celsius deviation, with a maximum increment not exceeding 2.5 m / s.

[0039] The usage method and advantages of the present invention: When the dissimilar metal laser welding device is working and in use, the working process is as follows: S1. Drive the laser welding gun 5 to move through the first guide rail 2 and the second guide rail 3, and process the dissimilar metal workpieces to be welded.

[0040] S2. During welding, the blower 8 blows air downward to cool the workpiece. During this process, the spring 10 pushes the baffle 9 to automatically press down and fit the surface of the workpiece, separating the welding point from the air-blowing area, so as to ensure that the air flow cools the workpiece while avoiding the air flow directly contacting the weld seam and affecting the welding effect.

[0041] S3. When switching the longitudinal and transverse movement of the laser welding gun 5, the frictional resistance between the limit pad 13 and the workpiece pulls the baffle 9 and the frame 7 to deflect along the gun head, so that the weld seam direction is always between the two baffles 9, thus avoiding the baffle 9 contacting the weld seam and affecting the welding effect.

[0042] S4. During welding, the micro motor 17 drives the upper cam 18 and intermittently pushes the lower cam 19 to make the flap 11 open and close periodically. The bottoms of the two baffles 9 fit to separate the upper area of the weld seam, and the weld seam is changed to communicate with the outside of the baffle 9. At this time, the air flow of the blower 8 cools the separated area along the inclined baffle 9, so as to control the weld seam to alternately communicate with the two heat dissipation areas by the deflection of the flap 11, avoid heat accumulation inside the baffle 9, and improve the heat dissipation efficiency of the weld seam area.

[0043] The above shows and describes the basic principle, main features and advantages of the present invention. Those skilled in the art of this industry should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A heterogeneous metal laser welding device, characterized in that, Including: A base (1) with a welding area provided at its top, and two first guide rails (2) are fixed by columns; A second guide rail (3) is slidably disposed on the first guide rail (2), and a moving seat (4) is slidably disposed on the second guide rail (3); A laser welding torch (5) is slidably disposed on the moving seat (4), and its gun head is rotatably connected to a ring seat (6); A frame (7) is eccentrically fixed to the ring seat (6), and two groups of downward-blowing blowers (8) and a bottom baffle (9) are symmetrically provided. The baffle (9) presses a welded part through a spring (10); A flap (11) controlled by a cam mechanism is provided on the surface of the baffle (9), and a through groove (12) for the laser beam to pass through is opened on its working surface.

2. The heterogeneous metal laser welding device according to claim 1, characterized in that: A limiting pad (13) with frictional resistance is provided at the bottom of the baffle (9); The ring seat (6) is provided with a clamping groove (14) and a notch (15), and the frame (7) is detachably fixed by a buckle (16); 3. The heterogeneous metal laser welding device according to claim 1, characterized in that: The deflection angle of the flap (11) is 0° - 20°; The cam mechanism includes an upper cam (18) driven by a micro motor (17) and a lower cam (19) connected to the shaft rod of the flap (11).

4. A heterogeneous metal laser welding device according to claim 1, characterized in that: The welding area is provided with a replaceable high-temperature resistant backing plate, and the surface of the backing plate is provided with a positioning groove matching the contour of the heterogeneous metal welded part.

5. A heterogeneous metal laser welding device according to claim 1, characterized in that: The moving seat (4) is integrated with a laser positioning module, including a CCD camera and a cross laser indicator.

6. The heterogeneous metal laser welding device according to claim 1, wherein: The air outlet of the blower (8) has a gradually shrinking Venturi structure, and a temperature sensor is embedded in the baffle (9).

7. A heterogeneous metal laser welding device according to claim 1, characterized in that: A quick-release protective gas nozzle is provided on the side of the frame (7), and the nozzle angle can be adjusted through a universal joint.

8. A heterogeneous metal laser welding device according to claim 1, characterized in that: An electromagnetic shielding layer is provided inside the base (1).

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