In-situ pulse current assisted laser welding device and method

Abstract

The present invention relates to the field of laser welding technology, and in particular to an in-situ pulse current assisted laser welding device and method, the device comprising: a frame, a screw module, a module support plate, a laser head, a positive and negative roller electrode auxiliary device, a substrate, a power cord and a pulse power supply; when working, the laser head is used to emit a laser to a workpiece to be operated for welding, and the positive and negative roller electrode auxiliary device is used to contact the workpiece to be operated and apply rolling pressure and pulse current. The present invention uses pulse current to assist laser welding to solve weld defects such as pores, cracks and larger dendrites, thereby refining the weld structure, improving joint performance, strictly controlling the size and shape of the weld structure in precision welding situations, and controlling the number of welding defects.

Description

Technical Field

[0001] The invention relates to the technical field of laser welding, and in particular to an in-situ pulse current assisted laser welding device and method. Background Art

[0002] Laser welding is a high-precision and high-efficiency material joining technology. Laser welding technology was developed in the 1960s and was mainly used for precision welding in the aerospace and defense fields. With the continuous advancement of laser technology and the expansion of its application fields, laser welding has gradually become a widely used welding method in the manufacturing industry. Its uniqueness lies in the use of the high energy density of the laser beam, which can achieve rapid heating and cooling, thereby achieving high-speed and high-quality welding. In recent years, with the continuous improvement of lasers, control systems and auxiliary equipment, laser welding technology has been widely used in automobile manufacturing, shipbuilding, electronic equipment manufacturing and other fields.

[0003] However, when traditional laser welding is applied to materials with high reflectivity and high thermal conductivity, such as aluminum alloys and copper alloys, it is more likely to produce pores and large dendrites or cracks. Therefore, when laser welding is applied to the precision welding of such materials, its weld morphology and welding quality need to be improved. Summary of the invention

[0004] In order to solve one of the above-mentioned problems, the present invention provides an in-situ pulse current assisted laser welding device and method, which aims to solve the problem that pores and large dendrites or crack defects are easily generated when traditional laser welding is applied to high reflectivity and high thermal conductivity materials, resulting in reduced weld quality, thereby reducing weld joint defects and improving the mechanical properties of the weld joint such as tensile strength and elongation.

[0005] To realize the above invention, the present invention provides an in-situ pulse current assisted laser welding device, comprising: a frame 1, a screw module 2, a module support plate 3, a laser head 4, a positive and negative roller electrode auxiliary device 5, a substrate 6, a power cord 7 and a pulse power supply 8; the frame 1 is arranged in a cubic shape and has a storage space; the module support plate 3 spans the top of the frame 1 and is fixed to the top crossbeam of the frame 1 through the top threaded holes on both sides, for supporting the screw module 2; the screw module 2 is installed on the module support plate 3, and is slidably connected to and drives the laser head 4 and the positive and negative roller electrode auxiliary device 5 respectively. movement; the laser head 4 and the positive and negative roller electrode auxiliary device 5 are arranged inside the accommodating space; the substrate 6 is placed at the bottom of the frame 1, and a moving workbench 61 is arranged on the substrate 6, wherein the moving workbench 61 is used to place the workpiece 9 to be operated and drive the workpiece 9 to be operated to move; one end of the power cord 7 is connected to the positive and negative roller electrode auxiliary device 5, and the other end is connected to the pulse power supply 8; when working, the laser head 4 is used to emit laser to the workpiece 9 to be operated for welding, and the positive and negative roller electrode auxiliary device 5 is used to contact the workpiece 9 to be operated and apply rolling pressure and pulse current.

[0006] On the other hand, the present invention provides an in-situ pulse current assisted laser welding method, comprising: starting the aforementioned in-situ pulse current assisted laser welding device; obtaining an adjustment instruction, and adjusting the laser head 4 and the positive and negative roller electrode auxiliary device 5 to a preset matching position through the screw module 2 according to the adjustment instruction; controlling the moving workbench 61 to obtain the workpiece 9 to be operated, and making the workpiece 9 to be operated contact the positive and negative roller electrode auxiliary device 5; controlling the laser head 4 to emit light and focus on the workpiece 9 to be operated for welding, and controlling the moving workbench 61 to move; controlling the pulse power supply 8 to release the pulse current, and passing the pulse current to the workpiece 9 to be operated through the positive and negative roller electrode auxiliary device 5.

[0007] The beneficial effects of the present invention are reflected in that the in-situ pulse current assisted laser welding device and method of the present invention can assist laser welding by pulse current, solve the problems of weld defects such as pores, cracks and large dendrites, thereby refining the weld structure, improving the joint performance, and strictly controlling the size and morphology of the weld structure in the case of precision welding, as well as controlling the number of welding defects. In addition, the in-situ pulse current assisted laser welding device and method of the present invention can apply pulse current in situ during the laser welding process by designing a special roller electrode auxiliary device, thereby stabilizing the welding process, improving the weld quality, and enhancing the forming effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1A three-dimensional diagram of the in-situ pulse current assisted laser welding device provided in Example 1 of the present invention;

[0009] Figure 2 Another stereoscopic view of the in-situ pulse current assisted laser welding device provided in Example 1 of the present invention;

[0010] Figure 3 A cross-sectional view of the in-situ pulse current assisted laser welding device provided in Example 1 of the present invention;

[0011] Figure 4 A front view of the positive roller electrode auxiliary device provided in Example 1 of the present invention;

[0012] Figure 5 A front cross-sectional view of the positive roller electrode auxiliary device provided in Example 1 of the present invention;

[0013] Figure 6 A side cross-sectional view of the positive roller electrode auxiliary device provided in Example 1 of the present invention;

[0014] Figure 7 The process parameters of the pulse current provided in Example 1 of the present invention;

[0015] Figure 8 This is a flow chart of the in-situ pulse current assisted laser welding method provided in Example 1 of the present invention.

[0016] Figure markings: 1-frame; 2-screw module; 21-X-axis positive electrode module; 22-X-axis negative electrode module; 23-Z-axis positive electrode module; 24-Z-axis negative electrode module; 25-X-axis laser head module; 26-Z-axis laser head module; 27-slider; 3-module support plate; 31-front module support plate; 32-rear module support plate; 4-laser head; 5-positive and negative roller electrode auxiliary device; 511-center axis; 512-electrode clip; 513-ceramic insulating sleeve; 514-conductive bearing; 515-bracket; 516-screw; 517-sleeve; 518-spring; 519-pressure sensor; 5110-clamp; 6-substrate; 61-moving workbench; 7-power cord; 8-pulse power supply; 9-workpiece to be operated. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Example 1

[0019] This embodiment provides an in-situ pulse current assisted laser welding device, referring to Figures 1 to 3 shown. Figure 1 and Figure 2 They are three-dimensional diagrams of the in-situ pulse current assisted laser welding device of this embodiment, Figure 3 FIG. 4 is a cross-sectional view of the in-situ pulse current assisted laser welding device of this embodiment. Figure 1 As shown, the in-situ pulse current assisted laser welding device of this embodiment includes: a frame 1, a screw module 2, a module support plate 3, a laser head 4, a positive and negative roller electrode auxiliary device 5, a substrate 6, a power cord 7 and a pulse power supply 8.

[0020] The frame 1 is arranged in a cubic shape and has a storage space; specifically, the frame 1 can be arranged in a regular cubic shape, fixed by multiple beams to form a cubic storage space, the screw module 2, the module support plate 3, the laser head 4, the positive and negative roller electrode auxiliary device 5, the substrate 6 and other components can be arranged inside the storage space, and the power cord 7 and the pulse power supply 8 can be arranged inside the storage space or outside the storage space. A triangular sheet metal can be arranged inside the frame 1 to fix and support the frame.

[0021] The module support plate 3 spans across the top of the frame 1 and is fixed to the top crossbeam of the frame 1 through the top threaded holes on both sides to support the screw module 2; specifically, the module support plate 3 is mainly used to fix and support the screw module 2, and the screw module 2 is fixed to the frame 1 through the module support plate 3.

[0022] The screw module 2 is mounted on the module support plate 3, and is slidably connected to and drives the laser head 4 and the positive and negative roller electrode auxiliary device 5 to move; specifically, the screw module 2 is used to support and connect the laser head 4 and the positive and negative roller electrode auxiliary device 5. The screw module 2 is fixedly mounted on the module support plate 3, and a slidable device (such as Figure 3 The laser head 4 and the positive and negative roller electrode auxiliary device 5 are connected by the slider 27 in the welding machine. The sliders 27 act in pairs to drive the laser head 4 and the positive and negative roller electrode auxiliary device 5 respectively. The screw module 2 can be adjusted manually or by mechanical arm braking. The movement of the laser head 4 and the positive and negative roller electrode auxiliary device 5 is controlled by the cooperation of the screw module 2 and the slider 27. The positions of the laser head 4 and the positive and negative roller electrode auxiliary device 5 can be adjusted before welding.

[0023] In an optional embodiment, the screw module 2 may include: an X-axis positive electrode module 21, an X-axis negative electrode module 22, a Z-axis positive electrode module 23, a Z-axis negative electrode module 24, an X-axis laser head module 25, and a Z-axis laser head module 26, wherein the relevant modules are combined in pairs through sliders, a total of 3 groups, respectively driving the movement of the laser head 4 and the positive and negative roller electrode auxiliary device 5. The X-axis positive electrode module 21 is slidably connected to the Z-axis positive electrode module 23, the X-axis negative electrode module 22 is slidably connected to the Z-axis negative electrode module 24; the X-axis laser head module 25 is slidably connected to the Z-axis laser head module 26. The positive and negative ends of the positive and negative roller electrode auxiliary device 5 can be connected to the Z-axis positive electrode module 23 and the Z-axis negative electrode module 24, respectively, and the laser head 4 is slidably mounted on the Z-axis laser head module 26. Before conducting the laser welding experiment, the relative positions of the laser head 4 and the positive and negative roller electrode auxiliary device 5 can be adjusted more accurately through the cooperation of multiple sets of screw modules to ensure accurate control of the welding process.

[0024] The laser head 4 and the positive and negative roller electrode auxiliary device 5 are arranged inside the accommodation space; specifically, the laser head 4 is used to emit laser light for welding during operation, and the positive and negative roller electrode auxiliary device 5 (also referred to as "roller electrode") is used to apply pulse current to the workpiece 9 to be operated during operation to assist welding. Applying pulse current during laser welding can adjust the depth, width and shape of the molten pool. When pulse current is introduced into laser welding, due to the uneven distribution of pulse current in the melt, there are different contraction forces and contraction effects at different positions, so that a contraction force gradient is formed in the melt, and the flow rate between each flow group is different, thereby causing shear stress; when the shear stress is large enough, the dendrites are broken and free in the liquid, becoming new grain growth centers, making the grains refined and spheroidized. Therefore, applying pulse current during laser welding can utilize the shear force effect to break the dendrites and refine the grain size. In addition, the pulse current can also utilize the thermodynamic effect to reduce the thermodynamic barrier of nucleation during welding. Because the pulse current input energy vibrates the molten pool, the magnetostriction effect prompts the crystal nuclei to be liberated from the mold wall and the melt to quickly lose superheat, increase the supercooling, thereby reducing the critical nucleation size. At the same time, the electric pulse inoculation effect is used to jointly improve the nucleation rate, increase the nucleation rate, produce more nucleation centroids, increase the uniformity of the solidification structure, significantly refine the grains, and transform the dendrites into equiaxed crystals, thereby effectively improving the solidification structure of the weld.

[0025] In addition, the positive and negative roller electrode auxiliary device 5 can apply pulse current in situ through the roller, and the roller can provide rolling effect on the weld, refine the microstructure (grain), improve the metal solidification structure, and further improve the performance of the weld joint.

[0026] In an optional embodiment, the positive and negative roller electrode auxiliary device 5 includes a positive roller electrode auxiliary device 51 and a negative roller electrode auxiliary device 52, and the positive roller electrode auxiliary device 51 and the negative roller electrode auxiliary device 52 are respectively located on both sides of the laser head 4. The positive roller electrode auxiliary device 51 is slidably mounted on the Z-axis positive electrode module 23, and the negative roller electrode auxiliary device 52 is slidably mounted on the Z-axis negative electrode module 24. The positive and negative electrodes of the roller electrode auxiliary device are arranged on both sides of the laser head 4 to ensure that the pulse current can be more effectively applied to the workpiece 9 to be operated. The light-emitting point of the laser head 4 and the conductive track of the positive and negative roller electrode auxiliary device 5 can be on the same line, so that the welding point is located at the expected position to achieve precise control of the welding process.

[0027] In an optional embodiment, a first conductive bearing is provided on the positive roller electrode auxiliary device 51, and a second conductive bearing is provided on the negative roller electrode auxiliary device 52; when working, the light emitting point of the laser head 4 is in a straight line with the trajectory of the first conductive bearing and the second conductive bearing. The two roller electrode auxiliary devices are located on both sides of the laser head, and the distance between the axes of the two roller electrode auxiliary devices can be set to a reasonable distance, for example, it can be set to 50mm. The two conductive bearings are used to rotatably contact the surface of the workpiece 9 to be operated, and their shape can be a circular roller shape. The material can be brass, and the diameter can be set to 42mm. By providing conductive bearings, the pulse current is transmitted to the conductive bearings during welding, so that the roller electrode auxiliary device can transmit the pulse current to the workpiece 9 to be operated.

[0028] In an optional embodiment, a pressure sensor may be provided in the positive and negative roller electrode auxiliary device 5, and the pressure sensor is used to monitor the rolling pressure applied by the positive and negative roller electrode auxiliary device 5 on the workpiece 9 to be operated. Specifically, by providing a pressure sensor in the roller electrode auxiliary device (a spring may also be provided if necessary), when the conductive bearing contacts the workpiece material, the pressure can be monitored by the reaction force brought to the conductive bearing by the workpiece, and the roller electrode can be adjusted according to the pressure, so that the rolling effect of the roller electrode on the weld can be more finely regulated.

[0029] In this embodiment, the positive roller electrode auxiliary device 51 and the negative roller electrode auxiliary device 52 can be provided with the same structure. Therefore, in an optional embodiment, taking the positive roller electrode auxiliary device 51 as an example, the positive roller electrode auxiliary device 51 can include the following internal structure: Figures 4 to 6 Schematic diagram of each orientation of the positive roller electrode auxiliary device 51, Figure 4 is a front view of the positive roller electrode auxiliary device 51, Figure 5 is a front cross-sectional view of the positive roller electrode auxiliary device 51, Figure 6is a side cross-sectional view of the positive roller electrode auxiliary device 51. The structure of the negative roller electrode auxiliary device 52 is the same as that of the positive roller electrode auxiliary device 51, and will not be described in detail here.

[0030] like Figures 4 to 6 As shown, the positive roller electrode auxiliary device 51 includes a central shaft 511, an electrode clip 512, a ceramic insulating sleeve 513, a conductive bearing 514, a bracket 515, a screw 516, a sleeve 517, a spring 518, a pressure sensor 519 and a clamp 5110.

[0031] The conductive bearing 514 can be installed on the central shaft 511, and the ceramic insulating sleeve 513 is sleeved on the central shaft 511 and the front end thereof abuts against the conductive bearing 514. The ceramic insulating sleeves 513 on both sides are symmetrically distributed around the conductive bearing 514 to fix the position of the conductive bearing 514 and prevent it from slipping.

[0032] The electrode clip 512 can be installed on the central shaft 511, with the front end abutting against the rear end of the ceramic insulating sleeve 513, and the rear end abutting against the outer edge of the shaft. The electrode clip 512 is installed between the ceramic insulating sleeve 513 and the outer edge of the central shaft 511, and is in direct contact with the central shaft 511. By arranging the electrode clip 512 in the positive roller electrode auxiliary device 51, the pulse current is transmitted to the central shaft 511 through the electrode clip 512 during welding, and then transmitted from the central shaft 511 to the conductive bearing 514, so that the positive roller electrode auxiliary device 51 successfully introduces the pulse current.

[0033] The bracket 515 can be installed on the ceramic insulating sleeve 513, and the bracket 515 itself is not energized. The outer edge of the bracket 515 abuts against the inner end of the ceramic insulating sleeve 513, and is connected to the fixture 5110 through the cooperation of the screw 516 and the sleeve 517. The ceramic insulating sleeve 513 set in the positive roller electrode auxiliary device 51 prevents the bracket 515 from directly contacting and energizing the central axis 511, so that the pulse current directly flows into the molten pool, the welding molten pool is more stable, which helps to reduce welding defects, improve welding quality, and better maintain the uniformity and consistency of the weld.

[0034] A sleeve 517, a spring 518 and a pressure sensor 519 may be provided inside the fixture 5110, and the spring 518 is provided with a gasket. The screw 516 and the sleeve 517 provided in the positive roller electrode auxiliary device 51 allow the bracket 515 to be successfully connected and matched with the fixture 5110, and the threaded hole of the inner diameter of the sleeve 517 cooperates with the thread of the screw 516, so that during pulse current assisted laser welding, the stability of the welding molten pool is improved, the interference of external factors on the welding process is reduced, and the stability of the welding process is improved. The spring 518 and the pressure sensor 519 provided in the positive roller electrode auxiliary device 51 allow the conductive bearing 514 to contact the workpiece material, and the reaction force of the conductive bearing 514 contacting the workpiece 9 to be operated can be transmitted to the pressure sensor 519 through the bracket 515 driving the screw 516, the screw 516 driving the sleeve 517, and the sleeve 517 driving the spring 518. One end of the spring 518 contacts the sleeve 517, and the other end contacts the pressure sensor 519, and transmits the specific value to the pressure sensor 519, so that the rolling effect of the roller electrode on the weld can be more finely controlled. In this way, the workpiece can be ensured to be simultaneously subjected to the effects of pulse current and rolling during welding, thereby achieving a better welding effect.

[0035] In an optional embodiment, the module support plate 3 includes a front module support plate 31 and a rear module support plate 32, and the front module support plate 31 and the rear module support plate 32 are parallel and cross the top of the frame 1 with a gap; the X-axis positive electrode module 21 and the X-axis negative electrode module 22 are fixed on the front module support plate 31, and the X-axis laser head module 25 is fixed on the rear module support plate 32. Specifically, a certain gap can be left between the front and rear support plates to ensure that after the laser head 4 and the positive and negative roller electrode auxiliary device 5 are installed, the light emitting point of the laser head 4 and the trajectory of the conductive bearing 514 of the positive and negative roller electrode auxiliary device 5 are on the same line; the front module support plate 31 and the rear module support plate 32 are respectively fixed on the crossbeam of the frame 1 so that the laser head 4 and the positive and negative roller electrode auxiliary device 5 can only move in the X-axis and Z-axis directions, wherein the Y-axis direction is fixed and does not move. The movement of the device in the Y-axis direction is limited by fixing the screw module 2 and the module support plate 3, and the front and rear module support plates are installed at a certain distance, so that the light output point of the laser head 4 is in a line with the trajectory of the conductive bearing 514, so that the welding point is located at the expected position to achieve precise control of the welding process, reduce the occurrence of welding deformation, avoid unstable or uneven welding quality due to welding position offset, and ensure the stability and reliability of welding.

[0036] In an optional embodiment, during operation, the laser head 4 and the positive and negative roller electrode auxiliary device 5 are kept in a fixed position. Specifically, the relative positions of the laser head 4 and the positive and negative roller electrode auxiliary device 5 can be adjusted before welding, and once in the working state, they will no longer move, so that the fixing device reduces the complexity of movement and can avoid the problem of unstable welding quality caused by position changes.

[0037] The substrate 6 is placed at the bottom of the frame 1, and a moving workbench 61 is arranged on the substrate 6, wherein the moving workbench 61 is used to place the workpiece 9 to be operated and drive the workpiece 9 to be operated to move; specifically, the substrate 6 includes the moving workbench 61, and the moving workbench 61 can obtain or receive the workpiece 9 to be operated, and the workpiece 9 to be operated moves with the moving workbench 61, and the surface of the workpiece 9 to be operated contacts the conductive bearing 514 in the positive and negative roller electrode auxiliary device 5, so that the pulse current passes through the workpiece 9 to be operated. During the entire welding process, all devices except the moving workbench 61 remain fixed, and only the moving workbench 61 moves with the workpiece 9 to be operated, which makes the welding process smoother, increases the stability of the molten pool, and reduces the occurrence of welding deformation.

[0038] One end of the power cord 7 is connected to the positive and negative roller electrode auxiliary device 5, and the other end is connected to the pulse power supply 8; in an optional embodiment, the power cord 7 includes a positive line and a negative line; the positive line connects the positive roller electrode auxiliary device 51 and the positive electrode of the pulse power supply 8, and the negative line connects the negative roller electrode auxiliary device 52 and the negative electrode of the pulse power supply 8. Specifically, the workpiece 9 to be operated is placed on the moving workbench 61 and contacts the conductive bearing 514 in the positive and negative roller electrode auxiliary device 5; the power cord 7 is connected to the positive and negative electrode clips in the positive and negative roller electrode auxiliary device 5 respectively; the positive and negative electrodes of the pulse power supply 8 are connected to the positive and negative power cords.

[0039] When working, the laser head 4 is used to emit laser to the workpiece 9 to be operated for welding, and the positive and negative roller electrode auxiliary device 5 is used to contact the workpiece 9 to be operated and apply rolling pressure and pulse current. In specific operation, the laser is turned on to make the laser head 4 emit light and focus on the surface of the workpiece 9 to be operated, and then the moving table 61 is started, and the moving table 61 moves with the workpiece to perform welding; at the same time, the pulse power supply 8 is turned on to release the pulse current, coupling and assisting the laser welding process.

[0040] In a specific embodiment, the working principle of the present invention can be described as follows: when performing a pulse current assisted laser welding experiment, the screw module 2 is used in advance for precise positioning, so that the distance between the laser head 4 and the positive and negative roller electrode auxiliary device 5 is 25 mm, the workpiece 9 to be operated is placed on the moving workbench 61, so that its upper surface is in contact with the conductive bearing 514, and then the pulse power supply 8 is turned on, and the pulse current acts on the electrode clip 512 through the power line 7, so that the conductive bearing 514 is energized, and the conductive bearing 514 is in contact with the upper surface of the workpiece 9 to be operated, and the positive and negative electrode clips 512 form a loop with the workpiece 9 to be operated, so that the workpiece 9 to be operated can flow into the pulse current, and then the laser is turned on so that the laser head 4 starts to emit light, focusing on the surface of the workpiece 9 to be operated to perform welding. Among them, for the roller electrode auxiliary device 5, when the pulse current is passed, the current passes through the electrode clip 512 to energize the central axis 511, so that the pulse current is passed through the conductive bearing 514. The content not described in detail in this specification belongs to the prior art known to professional and technical personnel in this field.

[0041] In an optional embodiment, the process parameters that can be selected for the pulse power supply 8 are a current frequency of 33 Hz, a duty cycle of 50%, and a current amplitude of 6 kA (eg Figure 7 As shown). During the pulse current assisted laser welding process, the pulse current is continuously supplied. By adjusting the appropriate pulse current parameters, the temperature distribution in the welding area can be changed, the liquid metal sputtering on the surface of the molten pool can be reduced, the defects in the welding process can be reduced, the occurrence of welding cracks can be reduced, and it is helpful to optimize the weld morphology and joint quality.

[0042] The in-situ pulse current assisted laser welding device provided in this embodiment can solve the problems of weld defects such as pores, cracks and large dendrites by assisting laser welding with pulse current, thereby refining the weld structure, improving the joint performance, and strictly controlling the size and shape of the weld structure in the case of precision welding, as well as controlling the number of welding defects. In addition, the in-situ pulse current assisted laser welding device of this embodiment can apply pulse current in situ during the laser welding process by designing a special roller electrode auxiliary device, thereby stabilizing the welding process, improving the weld quality, and enhancing the forming effect.

[0043] This embodiment also provides an in-situ pulse current assisted laser welding method, which uses the aforementioned in-situ pulse current assisted laser welding device to complete the welding operation on the workpiece 9 to be operated. The specific structure of the in-situ pulse current assisted laser welding device has been explained in detail above and will not be repeated here. Figure 8 As shown, the in-situ pulse current assisted laser welding method includes:

[0044] Step S801, start the in-situ pulse current assisted laser welding device; specifically, the in-situ pulse current assisted laser welding device can be assembled in advance, and the pulse power supply 8 is connected and powered on.

[0045] Step S802, obtain adjustment instructions, and adjust the laser head 4 and the positive and negative roller electrode auxiliary device 5 to the preset matching position through the screw module 2 according to the adjustment instructions; specifically, the positions of the laser head 4 and the positive and negative roller electrode auxiliary device 5 can be adjusted manually or by mechanical arm braking adjustment according to the adjustment instructions. By adjusting the laser head 4 and the positive and negative roller electrode auxiliary device 5 to the preset matching position, the light emitting point of the laser head 4 and the conductive track of the positive and negative roller electrode auxiliary device 5 can be on the same line, so that the welding point is located at the expected position to achieve precise control of the welding process.

[0046] Step S803, control the moving workbench 61 to obtain the workpiece 9 to be operated, and make the workpiece 9 to be operated contact the positive and negative roller electrode auxiliary device 5; specifically, the workpiece 9 to be operated can be transferred to the moving workbench 61 through the conveying device, and the moving workbench drives the workpiece 9 to be operated to move to a suitable position until it contacts the positive and negative roller electrode auxiliary device 5.

[0047] Step S804, control the laser head 4 to emit light and focus on the workpiece 9 to be operated for welding, and control the moving workbench 61 to move; specifically, control the laser head 4 of the laser to emit laser to start welding, and during the welding process, the moving workbench 61 drives the workpiece to move, and other accessories are kept fixed.

[0048] Step S805, control the pulse power supply 8 to release the pulse current, and pass the pulse current to the workpiece 9 to be operated through the positive and negative roller electrode auxiliary device 5. Specifically, after the welding operation starts, the pulse current is passed through the conductive bearings of the positive and negative roller electrode auxiliary device 5 to assist welding.

[0049] The in-situ pulse current assisted laser welding method provided in this embodiment aims to assist laser welding by pulse current, which can solve the problems of weld defects such as pores, cracks and large dendrites, thereby refining the weld structure, improving the joint performance, and strictly controlling the size and morphology of the weld structure in the case of precision welding, as well as controlling the number of welding defects. In addition, the in-situ pulse current assisted laser welding method of this embodiment uses a roller electrode auxiliary device to apply pulse current in situ during the laser welding process, thereby stabilizing the welding process, improving the weld quality, and enhancing the forming effect.

[0050] Example 2

[0051] This embodiment uses 2219T6 aluminum alloy with a size of 200mm×100mm×3.5mm as the workpiece material to be operated for laser welding. The specific steps are as follows:

[0052] (1) The 2219T6 aluminum alloy plate is subjected to pre-welding treatment to remove the refractory oxide film on its surface, and then is polished and smoothed, and is transferred through a transfer device and fixed on a moving workbench 61.

[0053] (2) Start the in-situ pulse current assisted laser welding device to perform laser welding on 2219T6 aluminum alloy. The laser welding process parameters are: laser power 2900W, welding speed 0.6m / min, spot diameter 0.2mm, shielding gas argon, flow rate 25L / min.

[0054] The tensile strength of the welded joint prepared in this embodiment can reach 261.2 MPa, which is 60.2% of the parent material strength of 434 MPa.

[0055] Example 3

[0056] This embodiment uses 2219T6 aluminum alloy with a size of 200mm×100mm×3.5mm as the workpiece material to be operated for laser welding, and applies pulse current during the laser welding experiment. The steps are:

[0057] (1) The 2219T6 aluminum alloy plate is subjected to pre-welding treatment to remove the refractory oxide film on its surface, and then is polished and smoothed, and is transferred through a transfer device and fixed on a moving workbench 61.

[0058] (2) By adjusting the screw module 2, the laser head 4 and the positive and negative roller electrode auxiliary device 5 are positioned and fixed, the distance between the two roller electrodes is 50 mm, and the conductive bearing 514 is in direct contact with the upper surface of the workpiece. Then, the laser is turned on to make the laser head 4 emit light and focus on the workpiece surface. Then, the moving table 61 is moved, and the moving table 61 moves with the workpiece to perform welding. The laser welding process parameters are: laser power 2900W, welding speed 0.6m / min, spot diameter 0.2mm, shielding gas is argon, and the flow rate is 25L / min.

[0059] (3) During laser welding, the conductive bearing 514 is connected to the pulse power supply 8 through the power line 7 clamped on the positive and negative electrode clips 512. The pulse power supply 8 works and releases pulse current to couple and assist the laser welding process. The process parameters of the pulse power supply 8 are a current frequency of 33 Hz, a duty cycle of 50%, and a current amplitude of 4 kA.

[0060] The tensile strength of the welded joint prepared in this embodiment can reach 278.2 MPa, which is 64.1% of the parent material strength of 434 MPa.

[0061] Example 4

[0062] This embodiment uses 2219T6 aluminum alloy with a size of 200mm×100mm×3.5mm as the workpiece material to be operated for laser welding, and applies pulse current during the laser welding experiment. The steps are:

[0063] (1) The 2219T6 aluminum alloy plate is subjected to pre-welding treatment to remove the refractory oxide film on its surface, and then is polished and smoothed, and is transferred through a transfer device and fixed on a moving workbench 61.

[0064] (2) By adjusting the screw module 2, the laser head 4 and the positive and negative roller electrode auxiliary device 5 are positioned and fixed, the distance between the two roller electrodes is 50 mm, and the conductive bearing 514 is in direct contact with the upper surface of the workpiece. Then, the laser is turned on to make the laser head 4 emit light and focus on the workpiece surface. Then, the moving table 61 is moved, and the moving table 61 moves with the workpiece to perform welding. The laser welding process parameters are: laser power 2900W, welding speed 0.6m / min, spot diameter 0.2mm, shielding gas is argon, and the flow rate is 25L / min.

[0065] (3) During laser welding, the conductive bearing 514 is connected to the pulse power supply 8 through the power line 7 clamped on the positive and negative electrode clips 512. The pulse power supply 8 works and releases pulse current to couple and assist the laser welding process. The process parameters of the pulse power supply 8 are a current frequency of 33 Hz, a duty cycle of 50%, and a current amplitude of 6 kA.

[0066] The tensile strength of the welded joint prepared in this embodiment can reach 297.9 MPa, which is 68.6% of the parent material strength of 434 MPa.

[0067] In the description of the embodiments of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "center", "top", "bottom", "top", "bottom", "inside", "outside", "inner side", "outer side" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Among them, "inside" refers to an internal or enclosed area or space. "Periphery" refers to the area surrounding a specific component or a specific area.

[0068] In the description of the embodiments of the present invention, the terms "first", "second", "third", and "fourth" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", "third", and "fourth" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0069] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", and "assemble" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0070] In the description of the embodiments of the present invention, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0071] In the description of the embodiments of the present invention, it should be understood that "-" and "~" represent a range between two values, and the range includes the endpoints. For example: "AB" represents a range greater than or equal to A and less than or equal to B. "A~B" represents a range greater than or equal to A and less than or equal to B.

[0072] In the description of the embodiments of the present invention, the term "and / or" herein is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " herein generally indicates that the associated objects before and after are in an "or" relationship.

[0073] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An in-situ pulse current assisted laser welding device, characterized in that: include: A frame (1), a screw module (2), a module support plate (3), a laser head (4), a positive and negative roller electrode auxiliary device (5), a substrate (6), a power cord (7) and a pulse power supply (8); The frame (1) is arranged in a cubic shape and has a receiving space; The module support plate (3) spans across the top of the frame (1) and is fixed to the top crossbeam of the frame (1) through threaded holes on the top of both sides, so as to support the screw module (2); The screw module (2) is mounted on the module support plate (3), and is slidably connected to and drives the laser head (4) and the positive and negative roller electrode auxiliary device (5) to move; The positive and negative roller electrode auxiliary devices (5) comprise a positive roller electrode auxiliary device (51) and a negative roller electrode auxiliary device (52); the positive roller electrode auxiliary device (51) and the negative roller electrode auxiliary device (52) are respectively located on two sides of the laser head (4); a first conductive bearing is provided on the positive roller electrode auxiliary device (51), and a second conductive bearing is provided on the negative roller electrode auxiliary device (52); The screw module (2) comprises: an X-axis positive electrode module (21), an X-axis negative electrode module (22), a Z-axis positive electrode module (23), a Z-axis negative electrode module (24), an X-axis laser head module (25) and a Z-axis laser head module (26); the X-axis positive electrode module (21) is slidably connected to the Z-axis positive electrode module (23), the X-axis negative electrode module (22) is slidably connected to the Z-axis negative electrode module (24), and the X-axis laser head module (25) is slidably connected to the Z-axis laser head module (26); the positive roller electrode auxiliary device (51) is slidably mounted on the Z-axis positive electrode module (23), the negative roller electrode auxiliary device (52) is slidably mounted on the Z-axis negative electrode module (24), and the laser head (4) is slidably mounted on the Z-axis laser head module (26); The laser head (4) and the positive and negative roller electrode auxiliary device (5) are arranged inside the accommodating space; The base plate (6) is placed at the bottom of the frame (1), and a moving workbench (61) is provided on the base plate (6), wherein the moving workbench (61) is used to place a workpiece (9) to be operated and to drive the workpiece (9) to be operated to move; One end of the power line (7) is connected to the positive and negative roller electrode auxiliary device (5), and the other end is connected to the pulse power supply (8); During operation, the laser head (4) and the positive and negative roller electrode auxiliary device (5) are maintained at fixed positions, the laser head (4) is used to emit laser light to the workpiece (9) to be operated for welding, the light emission point of the laser head (4) is in a straight line with the tracks of the first conductive bearing and the second conductive bearing, and the positive and negative roller electrode auxiliary device (5) is used to contact the workpiece (9) to be operated and apply rolling pressure and pulse current.

2. The in-situ pulse current assisted laser welding device according to claim 1, characterized in that: The module support plate (3) comprises a front module support plate (31) and a rear module support plate (32), wherein the front module support plate (31) and the rear module support plate (32) are parallel to and span the top of the frame (1) with a gap therebetween; The X-axis positive electrode module (21) and the X-axis negative electrode module (22) are fixed on the front module support plate (31), and the X-axis laser head module (25) is fixed on the rear module support plate (32).

3. The in-situ pulse current assisted laser welding device according to claim 1, characterized in that: The power line (7) comprises a positive line and a negative line; The positive line connects the positive roller electrode auxiliary device (51) and the positive electrode of the pulse power supply (8), and the negative line connects the negative roller electrode auxiliary device (52) and the negative electrode of the pulse power supply (8).

4. The in-situ pulse current assisted laser welding device according to claim 1, characterized in that: The positive and negative roller electrode auxiliary device (5) is provided with a pressure sensor, and the pressure sensor is used to monitor the rolling pressure applied by the positive and negative roller electrode auxiliary device (5) on the workpiece (9) to be operated.

5. An in-situ pulse current assisted laser welding method, characterized in that: include: Starting the in-situ pulse current assisted laser welding device according to claims 1 to 4; Acquiring an adjustment instruction, and adjusting the laser head (4) and the positive and negative roller electrode auxiliary device (5) to a preset matching position through the screw module (2) according to the adjustment instruction; Controlling the moving workbench (61) to obtain the workpiece to be operated (9), and making the workpiece to be operated (9) contact the positive and negative roller electrode auxiliary device (5); Controlling the laser head (4) to emit light and focus on the workpiece (9) to be operated for welding, and controlling the movement of the moving worktable (61); The pulse power supply (8) is controlled to release the pulse current, and the pulse current is passed to the workpiece (9) to be operated through the positive and negative roller electrode auxiliary device (5).

Images