A laser welding method and device for metal sandwich panels based on laser pulse swing

Abstract

The present invention relates to the technical field of welding, and provides a laser welding method and device for metal sandwich panels based on laser pulse oscillation. The welding device includes a laser head, a controller, and a laser. The laser is used to output laser light and transmit it to the laser head. The laser head is used to focus the output laser light to form a guiding laser beam, and the laser beam swings left and right on the weld of the metal sandwich panel. The controller collects the oscillation parameters of the received laser beam and controls the output power of the laser through the controller to change the energy of the laser beam at different oscillation positions, so that the laser power pulse frequency and the spatial oscillation frequency of the laser beam are of the same frequency and in the same phase. By using the coupling control of the two in time and space, the differential distribution of the laser beam energy increases the welding energy on both sides of the weld, the morphology of the lap weld is "U"-shaped, the effective melting area of the weld is increased, and the accurate control of the heat input of the weld is realized to obtain the expected weld profile size and meet different connection strength requirements.

Description

Technical Field

[0001] The invention relates to the technical field of welding, and in particular to a laser welding method and device for metal sandwich panels based on laser pulse swing. Background Art

[0002] Sandwich panels usually have a multi-layer structure. Due to the special nature of their structure, the traditional conventional welding process is relatively complicated and difficult to implement, and will cause large welding deformation. As an advanced welding manufacturing method, laser welding has the advantages of high welding efficiency, small welding deformation, high weld quality, and one-time deep penetration welding, making it an effective means to quickly and efficiently manufacture sandwich panel structures.

[0003] At present, conventional laser welding can achieve the welding of sandwich panel joints of 2mm and below. However, as the thickness of the sandwich panel substrate increases, the weld will present a "T" shape due to the concentrated energy density of the conventional laser, resulting in a smaller effective melting area of the weld and reduced welding strength. By increasing the swing of the laser beam, the spot energy density of the laser beam is reduced, but because the energy distribution of the conventional swing laser is uniform, the welding energy on both sides of the weld is insufficient, resulting in an insignificant increase in the effective melting area of the weld.

[0004] CN111037099A discloses a laser welding method and system for the end faces of copper and its alloy plates of unequal thickness, and proposes that the laser beam power, laser beam swing amplitude and swing frequency can be set according to the thickness of the first plate and the second plate to be welded, so as to stably weld copper and its alloy plates of unequal thickness, ensure that the end faces are fully covered, and the surface weld transition is smooth. However, the following problems still exist: 1. The laser beam swing is a sine wave, while the laser power is a linear wave, and the synergistic effect of the two is poor, and effective time-space coupling cannot be achieved, resulting in unsatisfactory welding effect; 2. The precise control of the laser power at each swing position is not achieved, and only a simple linear change at different deviations is used to control the laser power in each area, with poor accuracy; 3. The laser power control accuracy is poor, there is no gas protection device, and welding defects such as pores are prone to occur, and the applicability to the equal-thickness end face welding or sandwich panels of closed active metals is poor. Summary of the invention

[0005] In view of this, the present invention aims to propose a metal sandwich panel laser welding method and device based on laser pulse oscillation to solve the problem of small effective melting area and low connection strength of lap welds.

[0006] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0007] On the one hand, the present invention provides a laser welding method for metal sandwich panels based on laser pulse swing. A laser welding device is used, and the laser welding device includes a laser head, a controller, and a laser. The laser head and the laser are respectively connected to the controller. The laser is used to output laser light, which is transmitted to the laser head through an optical fiber. The laser head is used to focus the laser light output by the laser to form a guiding laser beam. The laser beam swings left and right on the weld of the metal sandwich panel for welding the metal sandwich panel. The controller collects the swing parameters of the laser beam and controls the output power and the output pulse waveform of the laser as a sine wave through the controller. By changing the output power, the energy of the laser beam at different swing positions is changed, so that the laser power pulse frequency and the laser beam spatial swing frequency are of the same frequency and in the same phase. The present invention utilizes the high-precision coupling control of the two in time and space. The differential distribution of the laser beam energy increases the welding energy on both sides of the weld. The morphology of the lap weld is in a "U" shape, increasing the effective melting area of the weld. The coupling of the laser power pulse frequency and the laser beam spatial swing frequency can better control the laser beam energy distribution on the laser beam swing trajectory, realize the accurate control of the heat input of the weld, obtain the expected weld profile size, meet different connection strength requirements, and can be used for welding substrates with increased thickness.

[0008] Further, the pulse waveform of the laser is a sine wave. When the laser beam swings to the two side positions, namely the leftmost position and the rightmost position of the laser beam, the corresponding powers are P1 and P3 respectively. At this time, the laser power is at the peak value P 峰 , when swinging to the middle position, the corresponding power is P2. At this time, the laser power is at the base value P 基 .

[0009] Further, the laser power output by the laser is determined by the following formula:

[0010]

[0011] where P is the instantaneous power of the laser output by the laser, with the unit of W;

[0012] P 峰 is the peak power, with the unit of W;

[0013] P 基 is the base value power, with the unit of W;

[0014] t is the time, with the unit of s;

[0015] T1 is the thickness of the upper layer plate of the metal sandwich panel, with the unit of mm;

[0016] S is the depth of the weld, with the unit of mm;

[0017] k is the phase coordination repair coefficient, with the unit of s;

[0018] D is the position distance of the laser beam swing, with the unit of mm.

[0019] Furthermore, the laser welding method is used for welding a metal sandwich panel, which successively includes an upper substrate, a sandwich panel, and a lower substrate. The laser welding method specifically includes the following steps:

[0020] Step 1: Pickle the upper substrate, the sandwich panel, and the lower substrate. There is a first weld seam on the upper substrate, and then clean the area within the range of 20 - 40 mm from the first weld seam area;

[0021] Step 2: Assemble and spot - weld the upper substrate, the sandwich panel, and the lower substrate. The assembly gap should be less than 0.5 mm;

[0022] Step 3: Fix the workpiece to be welded with a fixture, adjust the trajectory of the laser beam so that the spot formed by the laser beam is exactly in the middle of the area to be welded, and the offset error of the spot is less than 0.3 mm;

[0023] Step 4: Set the spatial swing amplitude, swing frequency, and welding speed of the laser beam according to the process requirements;

[0024] Step 5: Set the laser pulse power output as a sine wave. Through the controller, set the laser power pulse frequency to be the same as and in the same phase as the laser beam spatial swing frequency, and set the peak power P1 and P3, and the base power P2, so that when the laser beam swings to the positions on both sides of the first weld seam, the power is at P1 or P3, and when the laser beam swings to the middle position of the first weld seam, the power is at P2;

[0025] Step 6: Pass in argon gas to ensure that from the start to the end of welding, the first weld seam area and the heat - affected area are in an argon gas atmosphere;

[0026] Step 7: Start welding. The laser beam generates a lateral swing, and the laser beam moves at the set welding speed, presenting a wavy swing trajectory on the first weld seam;

[0027] Step 8: After reaching the welding end point, stop the laser output to complete the welding of the upper substrate and the sandwich panel;

[0028] Step 9: Flip the metal sandwich panel so that the lower substrate is on the uppermost side. There is a second weld seam on the lower substrate;

[0029] Step 10: Repeat the operations of Step 3 to Step 7. After reaching the welding end point, stop the laser output. Through the second weld seam, complete the welding of the lower substrate and the sandwich panel to obtain the welded - together metal sandwich panel.

[0030] Furthermore, when welding the upper substrate and the sandwich panel, T1 is the thickness of the upper substrate, and when welding the lower substrate and the sandwich panel, T1 is the thickness of the lower substrate.

[0031] On the other hand, the present invention also provides a laser welding device, which adopts the above-mentioned laser welding method for metal sandwich panels based on laser pulse oscillation. The laser welding device includes two protection toolings, which are arranged on the upper layer plate of the metal sandwich panel, and the two protection toolings are arranged parallel to both sides of the weld seam. A cavity is formed between the two protection toolings to form a welding area to be welded. By providing the relatively arranged protection toolings, argon gas can diffuse in the cavity between the protection toolings, effectively protecting the weld seam.

[0032] Further, the protection tooling includes an air inlet pipe and air holes. The air holes are opened at one end face of the protection tooling facing the weld seam, and the air holes are arranged at the lower part of this end face. One end of the air inlet pipe is communicated with an argon gas source, and the other end is communicated with the protection tooling. Argon gas is introduced into the protection tooling through the air inlet pipe, overflows into the cavity through the air holes, and evenly sinks to the welding area to be welded. Since the density of argon gas is relatively large, it can discharge the air in the upper area of the cavity upward until the argon gas diffuses throughout the cavity area, realizing effective gas protection and ensuring the strength of the welded joint.

[0033] Compared with the prior art, the laser welding method and device for metal sandwich panels based on laser pulse oscillation of the present invention have the following advantages:

[0034] 1. The laser power pulse frequency and the laser beam spatial oscillation frequency are of the same frequency and in the same phase, coupling them in time and space, which is beneficial to increasing the output power on both sides of the weld seam, making the appearance of the lap weld seam in a "U" shape with adjustable width, increasing the effective melting area and strength of the weld seam; a low power is adopted at the middle position of the weld seam to reduce the overall heat input and further reduce the welding deformation;

[0035] 2. By controlling the laser energy distribution on the laser beam oscillation trajectory, accurate control of the heat input of the weld seam is achieved, and the expected weld seam profile size can be obtained to meet the requirements of different connection strengths;

[0036] 3. Pulse and oscillation spatio-temporal coupled laser welding can reduce the requirements for assembly gaps in traditional laser welding;

[0037] 4. The protection toolings arranged parallel to both sides of the weld seam realize effective argon gas protection and ensure the strength of the welded joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0039] Figure 1Schematic structural diagram of a laser welding device for metal sandwich panels based on laser pulse swing according to the present invention;

[0040] Figure 2 Corresponding diagram of the laser power curve of the present invention, the swing trajectory of the laser beam on the weld, the metal sandwich panel, and the cross-sectional view of the weld;

[0041] Figure 3 Schematic structural diagram of the protection tooling according to the present invention;

[0042] Figure 4 Schematic diagram of the flow path of the argon shielding gas according to the present invention;

[0043] Figure 5 Metallographic cross-sectional view of the laser-welded sandwich panel in Example 1 of the present invention;

[0044] Figure 6 Metallographic cross-sectional view of the laser-welded sandwich panel in Comparative Example 1 of the present invention.

[0045] Explanation of reference numerals:

[0046] 1. Laser head; 2. Intermediate position; 3. Leftmost position; 4. Rightmost position; 5. Area to be welded; 6. Swing trajectory; 7. Weld; 8. Upper substrate; 9. Interlayer board; 10. Lower substrate; 11. Controller; 12. Laser; 13. Optical fiber; 14. Protection tooling; 15. Laser power curve; 16. Inlet pipe; 17. Air hole. Detailed implementation manners

[0047] The present invention will be further described below in conjunction with specific implementation manners. First, it should be noted that the data in the following experimental examples were obtained by the inventor through a large number of experiments. Due to space limitations, only a part of them are shown in the specification, and those of ordinary skill in the art can understand and implement the present invention based on this data. These examples are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these changes or modifications also fall within the scope protected by this application.

[0048] It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0049] The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments.

[0050] A laser welding method for metal sandwich panels based on laser pulse swing according to the present invention uses a laser welding device, such as Figure 1As shown in the figure, the laser welding device includes a laser head 1, a controller 11, and a laser 12. The laser head 1 and the laser 12 are respectively connected to the controller 11. The laser head 1 and the laser 12 are connected by an optical fiber 13. The laser 12 is used to output laser and transmit it to the laser head 1 through the optical fiber 13. The laser head 1 is used to focus the laser output by the laser 12 to form a guiding laser beam. The laser beam swings left and right on the weld 7 of the metal sandwich panel for welding the metal sandwich panel. The controller 11 collects the swing parameters of the received laser beam and controls the output power and the output pulse waveform of the laser 12 to be a sine wave through the controller 11. By changing the output power, the energy of the laser beam at different swing positions is changed, so that the laser power pulse frequency and the spatial swing frequency of the laser beam are of the same frequency and in the same phase.

[0051] The output power of the laser 12 is the power of the laser beam focused by the laser head 1. In the present invention, by regulating the laser 12, the energy of each phase of the swing trajectory 6 formed by the laser beam is differentially set, realizing the differential distribution of the energy of the laser beam at different swing positions, achieving the high-precision coupling control of the laser power pulse frequency output by the laser 12 and the spatial swing frequency of the laser beam focused by the laser head 1 in terms of time and space. The differential distribution of the laser beam energy increases the welding energy on both sides of the weld 7. The morphology of the overlapping weld 7 is in a "U" shape, increasing the effective melting area of the weld 7. It avoids the insufficient welding energy in the areas on both sides of the weld 7 caused by the uniform energy distribution after the laser beam swings. The coupling of the laser power pulse frequency and the spatial swing frequency of the laser beam can better control the energy distribution of the laser beam on the swing trajectory 6 of the laser beam, realizing the accurate control of the heat input of the weld, so as to obtain the expected cross-sectional size of the weld 7, meet different connection strength requirements, and can be used for welding substrates with increased thickness.

[0052] Under the action of the controller 11, the laser 12 of the present invention can control the laser power pulse frequency. Under the action of the controller 11, the laser head 1 can control the spatial swing frequency of the laser beam. The specific control method can refer to the prior art and will not be elaborated here.

[0053] A rotating lens is provided in the laser head 1. By adjusting the rotation posture of the lens, the laser beam can be made to swing spatially perpendicular to the welding direction. The main swing parameters include the swing frequency and the swing amplitude. The swing amplitude is determined according to the width of the weld 7 and the empirical value of the operator. Within a swing interval, the laser beam swings left and right at a specific swing amplitude. The high-frequency swing makes the laser beam form a linear heat source. The laser beam at the leftmost position 3 and the laser beam at the rightmost position 4 can increase the heating area and the heat input on both sides of the weld 7, thereby increasing the heated width of the weld 7.

[0054] Further, the pulse waveform of the laser is a sine wave. When the laser beam swings to both side positions, i.e., the leftmost position 3 and the rightmost position 4 of the laser beam, the corresponding powers are P1 and P3 respectively. At this time, the laser power is at the peak value P. 峰 When it swings to the middle position 2, the corresponding power is P2. At this time, the laser power is at the base value P. 基 The laser power output by the laser 12 is determined by the following formula:

[0055]

[0056] where P is the instantaneous power of the laser output by the laser 12, with the unit of W;

[0057] P 峰 is the peak power, with the unit of W;

[0058] P 基 is the base value power, with the unit of W;

[0059] t is the time, with the unit of s;

[0060] T1 is the thickness of the upper layer plate of the metal sandwich panel, with the unit of mm;

[0061] S is the depth of the weld 7, with the unit of mm;

[0062] k is the phase collaborative repair coefficient, with the unit of s;

[0063] D is the position distance of the laser beam swing, with the unit of mm.

[0064] During welding, the laser beam swings perpendicular to the welding direction. As Figure 2 shown, from top to bottom, it represents the laser power curve 15, the swing trajectory 6 of the laser beam on the weld 7, the cross-sectional view of the metal sandwich panel and the weld 7 in sequence. The laser pulse power output is a sine wave, and the swing trajectory 6 of the laser beam on the weld 7 is wavy. The determination of the laser power output by the laser 12 is related to the swing position of the laser beam. When the laser beam swings to the left and right side positions, the power is at the peak values of P1 or P3. The high-power laser on both sides of the weld 7 can increase the heating width, and the morphology of the lap weld 7 changes from a "T" shape or a "V" shape to a "U" shape with adjustable width. The effective melting area of the weld 7 increases significantly, and the strength of the lap weld 7 is significantly improved. When the laser beam swings to the middle position 2, the power is at the base value of P2, which can reduce the energy in the central area of the weld 7, reduce the overall heat input, and control the welding deformation. Through the formula of the laser power P output by the laser 12 of the present invention, the laser power at each swing position can be accurately controlled, and the control accuracy of the pulsed laser is high, realizing the precise control and improvement of the effective melting area of the weld.

[0065] During Figure 2In the cross-sectional view of the metal sandwich panel and the weld seam 7, C is the width of the weld seam 7, S is the depth of the weld seam 7, Y is the width of the effective melting area, T1 is the thickness of the upper substrate 8, and T2 is the thickness of the sandwich panel 9.

[0066] A laser welding method for metal sandwich panels based on laser pulse oscillation, which is used to weld metal sandwich panels. The metal sandwich panel sequentially includes an upper substrate 8, a sandwich panel 9, and a lower substrate 10. The welding method specifically includes the following steps:

[0067] Step 1: Pickle the upper substrate 8, the sandwich panel 9, and the lower substrate 10. There is a first weld seam on the upper substrate 8, and then clean the area within a range of 20 - 40 mm from the first weld seam area.

[0068] Specifically, when cleaning the area near the first weld seam, either a hard grinding head or laser cleaning can be used.

[0069] Step 2: Assemble and spot - weld the upper substrate 8, the sandwich panel 9, and the lower substrate 10. The assembly gap should be less than 0.5 mm.

[0070] Step 3: Fix the workpiece to be welded with a fixture, adjust the trajectory of the laser beam so that the spot formed by the laser beam is exactly in the middle of the area to be welded 5, and the deviation error of the spot is less than 0.3 mm.

[0071] Step 4: Set the spatial oscillation amplitude, oscillation frequency, and welding speed of the laser beam according to the process requirements.

[0072] Specifically, the oscillation amplitude is the distance between the left - most position 3 and the right - most position 4. The distance of the left - most position 3 of the laser beam is D1, the distance of the right - most position 4 is D3, and the distance of the middle position 2 is D2. The welding speed is 0.1 - 0.3 mm / s.

[0073] Step 5: Set the laser pulse power output as a sine wave. Through the controller 11, set the laser power pulse frequency to be the same as and in the same phase as the laser beam spatial oscillation frequency, and set the peak power P1 and P3, and the base power P2, so that when the laser beam swings to the left and right sides of the first weld seam, the power is at P1 or P3, and when the laser beam swings to the middle position of the first weld seam, the power is at P2.

[0074] Step 6: Introduce argon gas to ensure that from the start to the end of welding, the first weld seam area and the heat - affected area are in an argon gas atmosphere.

[0075] Step 7: Start welding. The laser beam generates a lateral oscillation, and the laser beam moves at the set welding speed, presenting a wavy oscillation trajectory 6 on the first weld seam.

[0076] The laser energy at each phase on the swing trajectory 6 is controlled by the controller 11. Therefore, the laser energy at each position on the wave trajectory can be precisely controlled, and the heat input in the first weld area is rationally distributed, which is conducive to controlling the size of the first weld and reducing welding deformation.

[0077] Step eight: After reaching the welding end point, the laser output stops, and the welding of the upper substrate 8 and the sandwich panel 9 is completed.

[0078] Step nine: Flip the metal sandwich panel so that the lower substrate 10 is located on the uppermost side, and the lower substrate 10 has a second weld.

[0079] Step ten: Repeat the operations in steps three to seven. After reaching the welding end point, the laser output stops, and the welding of the lower substrate 10 and the sandwich panel 9 is completed through the second weld, obtaining a welded metal sandwich panel.

[0080] Regarding the determination of the instantaneous power P of the laser output by the laser 12, when welding the upper substrate 8 and the sandwich panel 9, T1 is the thickness of the upper substrate 8, and when welding the lower substrate 10 and the sandwich panel 9, T1 is the thickness of the lower substrate 10.

[0081] The present invention also proposes a laser welding device, which includes two protection tools 14, as Figures 3 - 4 shown. The protection tools 14 are arranged on the upper layer plate of the metal sandwich panel, and the two protection tools 14 are arranged parallel to both sides of the weld 7, and a cavity is formed between the two protection tools 14 to form a welding area 5 to be welded. The weld 7 is located in the cavity. When welding the lap joint of the metal sandwich panel by using the laser welding method of the metal sandwich panel based on laser pulse swing, due to the large heat-affected area, the protection difficulty is also large, and oxidation at the joint is likely to cause a reduction in welding strength. Using a traditional moving drag shield for protection is inconvenient to operate. By setting the relatively arranged protection tools 14, argon gas can diffuse in the cavity between the protection tools 14, effectively protecting the weld 7. Figure 4 The arrow in

[0082] As a preferred embodiment of the present invention, the protection tool 14 includes an air inlet pipe 16 and air holes 17. The air holes 17 are opened on the end face of the protection tool 14 facing the weld 7, and the air holes 17 are arranged at the lower part of this end face. One end of the air inlet pipe 16 is communicated with the argon gas source, and the other end is communicated with the protection tool 14. Argon gas is introduced into the protection tool 14 through the air inlet pipe 16, overflows into the cavity through the air holes 17, and uniformly sinks to the welding area 5 to be welded. Since the density of argon gas is relatively large, it can discharge the air in the upper area of the cavity upward until the argon gas diffuses throughout the cavity area, realizing effective gas protection, reducing porosity defects, preventing weld oxidation, improving the weld forming quality, and ensuring the strength of the welded joint.

[0083] Adopting a laser welding method and device for metal sandwich panels based on laser pulse swing of the present invention has the following advantages:

[0084] 1. The laser power pulse frequency and the laser beam spatial swing frequency are of the same frequency and in the same phase, coupling them in time and space, which is beneficial to increasing the output power on both sides of the weld 7, making the appearance of the lap weld 7 in a "U" shape with adjustable width, increasing the effective melting area and strength of the weld 7; a low power is adopted at the middle position of the weld 7 to reduce the overall heat input and further reduce the welding deformation;

[0085] 2. By controlling the laser energy distribution on the laser beam swing trajectory 6, accurate control of the heat input of the weld 7 can be achieved, and the expected cross-sectional dimensions of the weld 7 can be obtained to meet the requirements of different connection strengths;

[0086] 3. Using pulsed and swing spatio-temporal coupled laser welding can reduce the requirements for assembly gaps in traditional laser welding;

[0087] 4. The protective tooling 14 arranged parallel to both sides of the weld 7 realizes effective argon gas protection and ensures the strength of the welded joint;

[0088] 5. High-efficiency welding of active metal sandwich panels such as titanium alloy or zirconium alloy can be achieved. Example 1

[0089] The metal sandwich panel described in the present invention can be a titanium alloy sandwich panel. The titanium alloy sandwich panel structure, as a lightweight, high specific stiffness, and high specific strength structure, has outstanding advantages in terms of fire resistance, shock absorption, fatigue resistance, and impact resistance.

[0090] Taking titanium alloy as an example in this embodiment. The base materials are the upper substrate 8 and the lower substrate 10 with a thickness of 3 mm, and the sandwich panel 9 with a thickness of 3 mm. The upper substrate 8, the sandwich panel 9, and the lower substrate 10 are welded using the laser welding method and welding device for metal sandwich panels based on laser pulse swing of the present invention. During the welding process, the laser 12 and the laser head 1 are controlled by the controller 11 to make the laser power pulse frequency and the laser beam spatial swing frequency of the same frequency and in the same phase. The laser power output by the laser 12 is determined by the following formula:

[0091] .

[0092] As Figure 5 shown, the morphology of the weld 7 obtained in Example 1 is in a "U" shape, and the width Y of the effective melting area of the weld 7 is 2.6 mm.

[0093] Comparative Example 1

[0094] Select titanium alloy as the workpiece to be welded. The selection of the base material is the same as that in Example 1, and the traditional laser welding method is adopted. As Figure 6 shown, the morphology of the weld seam 7 obtained in Comparative Example 1 is in a "T" shape, and the width Y of the effective melting area of the weld seam 7 is 1.2 mm.

[0095] Compared with Comparative Example 1, in Example 1 of the present invention, the width Y of the effective melting area of the weld seam 7 increases, and the strength of the overlapping weld seam 7 is increased by more than one time, which is suitable for high-quality welding of thick metal sandwich panels.

[0096] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A laser welding method for metal sandwich panels based on laser pulse swing, characterized in that, The lap weld (7) of the metal sandwich panel is welded by a laser welding device. The laser welding device includes a laser head (1), a controller (11) and a laser (12). The laser head (1) and the laser (12) are respectively connected to the controller (11). The laser (12) is used to output laser and transmit it to the laser head (1) through an optical fiber (13). The laser head (1) is used to focus the laser output by the laser (12) to form a guiding laser beam. The laser beam swings left and right on the weld (7) of the metal sandwich panel for welding the metal sandwich panel. The controller (11) collects and receives the swing parameters of the laser beam, and controls the output power and the output pulse waveform of the laser (12) to be a sine wave through the controller (11). By changing the output power, the energy of the laser beam at different swing positions is changed. When the laser beam swings to the leftmost position (3) and the rightmost position (4), the corresponding powers are P1 and P3 respectively. At this time, the laser power is at the peak value P 峰 . When it swings to the middle position (2), the corresponding power is P2. At this time, the laser power is at the base value P 基 .

2. The laser welding method for metal sandwich panels based on laser pulse swing according to claim 1, characterized in that, The described laser welding method is used for welding a metal sandwich panel, which successively includes an upper substrate (8), a sandwich panel (9) and a lower substrate (10). The laser welding method specifically includes the following steps: Step 1: Pickle the upper substrate (8), the sandwich panel (9) and the lower substrate (10). There is a first weld seam on the upper substrate (8), and then clean the area within a range of 20 - 40 mm from the first weld seam area; Step 2: Carry out assembly spot welding on the upper substrate (8), the sandwich panel (9) and the lower substrate (10). The assembly gap should be less than 0.5 mm; Step 3: Fix the workpiece to be welded with a fixture, and adjust the trajectory of the laser beam so that the spot formed by the laser beam is exactly in the middle of the area to be welded (5). The offset error of the spot is less than 0.3 mm; Step 4: Set the spatial swing amplitude, swing frequency and welding speed of the laser beam according to the process requirements; Step 5: Set the laser pulse power output as a sine wave. Set the laser power pulse frequency through the controller (11), and set the peak powers P1 and P3 and the base power P2 so that when the laser beam swings to the leftmost position (3) and the rightmost position (4), the laser powers are respectively at P1 and P3, and when it swings to the middle position (2) of the first weld seam, the power is at P2; Step 6: Introduce argon gas to ensure that from the start to the end of welding, the first weld seam area and the heat - affected area are in an argon gas atmosphere; Step 7: Start welding. The laser beam generates a lateral swing, and the laser beam moves at the set welding speed, presenting a wavy swing trajectory (6) on the first weld seam; Step 8: After reaching the welding end point, stop the laser output to complete the welding of the upper substrate (8) and the sandwich panel (9); Step 9: Flip the metal sandwich panel so that the lower substrate (10) is on the uppermost side. There is a second weld seam on the lower substrate (10); Step 10: Repeat the operations of Step 3 to Step 7. After reaching the welding end point, stop the laser output, and complete the welding of the lower substrate (10) and the sandwich panel (9) through the second weld seam to obtain the welded - together metal sandwich panel.

3. A laser welding device, characterized in that, The described laser welding device is used to implement the laser welding method for metal sandwich panels based on laser pulse swing according to any one of claims 1 - 2. The laser welding device includes two protection fixtures (14). The protection fixtures (14) are arranged on the upper layer plate of the metal sandwich panel, and the two protection fixtures (14) are arranged parallel to both sides of the weld seam (7). A cavity is formed between the two protection fixtures (14) to form the area to be welded (5).

4. The laser welding device according to claim 3, characterized in that, The protection fixture (14) includes an air inlet pipe (16) and air holes (17). The air holes (17) are opened on one end face of the protection fixture (14) facing the weld seam (7), and the air holes (17) are arranged at the lower part of this end face. One end of the air inlet pipe (16) is connected to an argon gas source, and the other end is connected to the protection fixture (14).

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