Laser welding system, laser welding control method, device and storage medium

Abstract

The present application relates to a laser welding system, a laser welding control method, a device and a storage medium, and belongs to the field of welding technology. The system includes: a workbench; a pad placed on the workbench; during welding, a first plate is placed on the workbench, and the thickness of the pad is the same as that of the first plate; a second plate is also placed on the first plate and the pad; a laser welding device with a scanning function performs laser scanning in a direction perpendicular to the welding direction during the welding process to weld the lap joint of the first plate and the second plate; the laser output power corresponding to at least two different laser scanning positions is different; it can solve the problems of complex system structure, large laser output power and serious deformation of welds when welding lap joints by laser filling wire; by controlling the energy distribution at different positions during laser scanning welding, the metal fusion ratio on both sides of the lap joint fillet weld can be controlled, thereby improving welding quality and reducing system complexity.

Description

Technical Field

[0001] The present application relates to a laser welding system, a laser welding control method, a device and a storage medium, and belongs to the field of welding technology. Background Art

[0002] Laser welding (also known as tailored welding) is a technique that uses a laser heat source to weld together sheets of different types, thicknesses, and sizes into a single piece. For example, laser welding can create fillet welds by joining overlapping sheets together.

[0003] In a typical lap joint welding method, defocused laser welding with filler wire is mainly used.

[0004] However, this welding method requires the installation of a wire feeding mechanism on the laser welding head, which makes the system more complicated. In addition, due to the need for laser defocused welding, the laser output power is high, resulting in a large heat-affected zone in the weld joint and severe deformation of the weldment. Summary of the Invention

[0005] This application provides a laser welding system, laser welding control method, device, and storage medium that can solve the problems of complex laser welding system structure, high laser output power, and severe weld deformation when welding lap joints using laser filler wire. This application provides the following technical solutions:

[0006] In a first aspect, a laser welding system is provided, the system comprising:

[0007] Workbench;

[0008] A backing plate is placed on the workbench; during the welding process, a first plate is placed on the workbench, and the thickness of the backing plate is the same as that of the first plate; a second plate is also placed on the first plate and the backing plate;

[0009] A laser welding device with a scanning function performs laser scanning in a direction perpendicular to the welding direction during the welding process to weld the lap joint of the first plate and the second plate; the laser output power of the laser welding device corresponding to at least two different laser scanning positions is different.

[0010] Optionally, after welding according to the laser output powers corresponding to the at least two different laser scanning positions, the fillet weld between the first plate and the second plate meets a desired welding standard.

[0011] Optionally, the desired welding standards include:

[0012] The undercut or collapse of the fillet weld front side is less than a preset threshold;

[0013] The back side of the first plate is not fully melted; and

[0014] The second sheet material melts evenly.

[0015] Optionally, the laser output power corresponding to each scanning position on the scanning trajectory of the laser scanning is determined based on the maximum laser output power; the maximum laser output power is related to the laser welding speed, the thermal physical performance coefficient corresponding to the first plate, and the thickness of the first plate.

[0016] Optionally, the laser output power between two adjacent laser scanning positions varies uniformly.

[0017] Optionally, the scanning track of the laser welding device includes a first area located on the first plate and a second area located on the second plate;

[0018] The laser output power corresponding to each first laser scanning position is: the product of the first weight corresponding to the first laser scanning position and the maximum laser output power; the first scanning distance of the first laser scanning position is negatively correlated with the first weight;

[0019] The laser output power corresponding to each second laser scanning position is: the product of the second weight corresponding to the second laser scanning position, the plate thickness ratio, and the maximum laser output power; the second scanning distance of the second laser scanning position is negatively correlated with the second weight; the plate thickness ratio is the ratio of the thickness of the second plate to the thickness of the first plate;

[0020] The laser output power corresponding to the third laser scanning position at the lap joint is: the sum of the thickness of the first plate and the thickness of the second plate divided by the thickness of the first plate, multiplied by the third weight and the maximum laser output power.

[0021] Optionally, the scanning trajectory is a periodic scanning trajectory; the scanning trajectory includes at least two laser scanning positions, and the at least two laser scanning positions are set according to the period of the scanning trajectory.

[0022] Optionally, the angle between the laser output axis of the laser welding device and the normal line of the first plate is positively correlated with the thickness of the second plate.

[0023] Optionally, the system further comprises a first pressing plate and a second pressing plate;

[0024] The first pressing plate is placed on the first plate to press the first plate;

[0025] The second pressing plate is placed on the second plate to press the second plate.

[0026] In a second aspect, a laser welding control method is provided, which is used in the system described in the first aspect, and the method includes:

[0027] Obtaining the laser output power corresponding to each laser scanning position; wherein the laser output powers corresponding to at least two different laser scanning positions are different;

[0028] During the welding process, laser scanning is performed in a direction perpendicular to the welding direction according to the laser output power corresponding to each laser scanning position to weld the overlap joint of the first plate and the second plate.

[0029] Optionally, obtaining the laser output power corresponding to each laser scanning position includes:

[0030] Obtaining a laser welding speed of the laser welding device, a thermophysical performance coefficient corresponding to the first plate, and a thickness of the first plate;

[0031] calculating a maximum laser output power based on a product of the laser welding speed, the thermophysical performance coefficient, and the thickness of the first plate;

[0032] The laser output power corresponding to each laser scanning position is determined based on the maximum laser output power.

[0033] Optionally, determining the laser output power corresponding to each laser scanning position based on the maximum laser output power includes:

[0034] Set the laser output power between two adjacent laser scanning positions to change uniformly.

[0035] Optionally, the scanning trajectory of the laser welding device includes a first area located on the first plate and a second area located on the second plate; and determining the laser output power corresponding to each laser scanning position based on the maximum laser output power includes:

[0036] The laser output power corresponding to each first laser scanning position is set to be: the product of the first weight corresponding to the first laser scanning position and the maximum laser output power; the first scanning distance of the first laser scanning position is negatively correlated with the first weight; the first laser scanning position is located in the first area;

[0037] The laser output power corresponding to each second laser scanning position is set to be: the product of the second weight corresponding to the second laser scanning position, the plate thickness ratio, and the maximum laser output power; the second scanning distance of the second laser scanning position is negatively correlated with the second weight; the plate thickness ratio is the ratio of the thickness of the second plate to the thickness of the first plate; the second laser scanning position is located in the second area;

[0038] The laser output power corresponding to each third laser scanning position on the lap joint is set to: the sum of the thickness of the first plate and the thickness of the second plate divided by the thickness of the first plate, multiplied by the third weight and the maximum laser output power.

[0039] Optionally, the scanning trajectory is a periodic scanning trajectory; and obtaining the laser output power corresponding to each laser scanning position includes:

[0040] Setting at least two laser scanning positions according to the period of the scanning trajectory;

[0041] The laser output powers corresponding to the at least two laser scanning positions are set.

[0042] Optionally, the laser scanning along a direction perpendicular to the welding direction includes:

[0043] Obtaining an angle between a laser output axis of the laser welding device and a normal line of the first plate, wherein the angle is positively correlated with a thickness of the second plate;

[0044] Laser scanning is performed along a direction perpendicular to the welding direction according to the angle.

[0045] In a third aspect, a laser welding control device is provided, which is used in the system described in the first aspect, and the device includes:

[0046] A power acquisition module is used to acquire the laser output power corresponding to each laser scanning position; wherein the laser output power corresponding to at least two different laser scanning positions is different;

[0047] The laser welding module is used to perform laser scanning in a direction perpendicular to the welding direction according to the laser output power corresponding to each laser scanning position during the welding process, so as to weld the lap joint of the first plate and the second plate.

[0048] In a fourth aspect, a laser welding control device is provided, comprising a processor and a memory; a program is stored in the memory, and the program is loaded and executed by the processor to implement the laser welding control method provided in the second aspect.

[0049] In a fifth aspect, a computer-readable storage medium is provided, wherein a program is stored in the storage medium, and when the program is executed by a processor, it is used to implement the laser welding control method provided in the second aspect.

[0050] The beneficial effects of the present application are as follows: by setting a workbench; placing a pad on the workbench; during the welding process, a first plate is placed on the workbench, and the thickness of the pad is the same as that of the first plate; a second plate is also placed on the first plate and the pad; a laser welding device with a scanning function performs laser scanning in a direction perpendicular to the welding direction during the welding process to weld the lap joint of the first plate and the second plate; the laser welding device has different laser output powers corresponding to at least two different laser scanning positions; it can solve the problem that when welding lap joints by laser filling wire, the laser welding system has a complex structure, a large laser output power, and severe deformation of the weldment; by controlling the energy distribution of the laser at different positions while laser scanning welding, the metal fusion ratio on both sides of the fillet weld of the lap joint of the metal plates can be controlled, the weld formation can be improved, and the welding quality can be improved. At the same time, there is no need to set up a wire feeding mechanism to achieve high-quality fillet welds, which can reduce the complexity of the laser welding system.

[0051] In addition, by determining the laser output power of each laser scanning position based on the maximum laser output power, the maximum laser power is related to the laser welding speed, the thermal physical performance coefficient corresponding to the first plate, and the thickness of the first plate. Therefore, the laser output power can be adaptively changed according to the plate, welding speed and thickness, thereby improving the flexibility of allocating laser output power.

[0052] In addition, by determining the angle between the laser output axis and the normal vector of the upper surface of the first plate according to the thickness of the second plate, the laser beam can be prevented from irradiating the upper surface of the second plate, thereby increasing the energy required for welding; thereby reducing the energy required for welding.

[0053] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application and to implement it in accordance with the contents of the specification, the following is a detailed description of the preferred embodiments of the present application in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is a schematic structural diagram of a laser welding system provided by one embodiment of the present application;

[0055] Figure 2 is a schematic diagram of a periodic scanning trajectory and laser output power provided by an embodiment of the present application;

[0056] Figure 3is a schematic diagram of a laser scanning position provided by an embodiment of the present application;

[0057] Figure 4 Schematic diagram of the angle between the laser output axis and the normal line of the first plate provided in one embodiment of the present application;

[0058] Figure 5 This is a flow chart of a laser welding control method provided by one embodiment of the present application;

[0059] Figure 6 This is a block diagram of a laser welding control device provided by one embodiment of the present application;

[0060] Figure 7 This is a block diagram of a laser welding control device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0061] The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0062] First, several terms involved in this application are introduced.

[0063] Laser Scanner Welding (LSW): The laser beam is incident on the X and Y axis reflectors of the scanning galvanometer. The computer controls the angle of the reflectors to achieve arbitrary deflection of the laser beam, so that the laser with a certain power density is focused on different positions on the surface of the workpiece to achieve the welding function.

[0064] The laser welding system provided in this application is described below. Optionally, the application scenario of the laser welding system provided in this embodiment includes welding a first plate and a second plate, where the second plate is overlapped on the first plate, i.e., the second plate is on top and the first plate is on the bottom, and a fillet weld is formed on the upper surface of the first plate and the side surface of the second plate.

[0065] In one scenario, the thickness of the first plate and the second plate is greater than 1 mm and less than 5 mm, the thickness of the second plate is δ1, the thickness of the first plate is δ2, and δ2 / δ1 is less than a first threshold and greater than a second threshold; the material of the first plate and the second plate is the same, and the material includes but is not limited to: one of stainless steel, carbon steel, high-strength steel and aluminum alloy.

[0066] The first threshold may be 2 or other values, and the second threshold may be 1 or other values. This embodiment does not limit the values ​​of the first threshold and the second threshold.

[0067] In other application scenarios, the thickness of the first plate and / or the second plate may also be less than or equal to 1 mm, or greater than or equal to 5 mm, and the materials of the first plate and the second plate may also be different. This embodiment does not limit the application scenarios of the laser welding system.

[0068] Figure 1 This is a schematic diagram of the structure of a laser welding system provided by an embodiment of the present application. Figure 1 It can be seen that the system at least includes: a workbench 11 , a backing plate 12 and a laser welding device 13 .

[0069] The workbench 11 is used to provide a working area for the laser welding system. The workbench 11 can be movable or fixed, and this embodiment does not limit the implementation of the workbench 11.

[0070] The pad 12 is placed on the workbench 11 ; during the welding process, a first plate 14 is placed on the workbench 11 , and the thickness of the pad 12 is the same as that of the first plate 14 ; a second plate 15 is also placed on the first plate 14 and the pad 12 .

[0071] During system installation, the first plate 14 is placed on the welding table 11, and a backing plate 12 of the same thickness as the first plate 14 is placed outside the first plate 14. One end of the second plate 15 is overlapped on the first plate 14, and the other end is placed on the backing plate 12 to ensure that the second plate 15 is placed stably.

[0072] In one example, the backing plate 12 is made of copper alloy. In other embodiments, the backing plate 12 may also be made of other materials, which are not listed here one by one.

[0073] Optionally, the first plate 14 and the second plate 15 are pre-treated before being placed on the backing plate 12. The pre-treated plates can consume lower energy during laser welding, thus saving the energy required for welding.

[0074] The pretreatment includes but is not limited to at least one of the following: grinding the butt joints and welding areas of the plates with a file or sandpaper, followed by cleaning with alcohol or acetone; or, after the aforementioned treatment, cleaning the aluminum alloy plates with a nitric acid, hydrochloric acid, or acetic acid solution with a mass concentration of 5% or more under a preset temperature environment to remove the oxide film on the surface; of course, the pretreatment method may also include other methods, which are not listed here in this embodiment. The preset temperature environment may be a temperature environment of 30-50°C. Of course, the temperature range of the temperature environment may also be adjusted according to actual needs. This embodiment does not limit the setting method of the temperature environment.

[0075] Optionally, to ensure the stability of the first and second plates during welding, after the first and second plates are placed on the backing plate, a first pressing plate 16 may be placed on the first plate to compress the first plate, and a second pressing plate 17 may be placed on the second plate to compress the second plate. In this case, the laser welding system also includes the first pressing plate 16 and the second pressing plate 17.

[0076] The laser welding device 13 has a scanning function and can adjust the laser output power of the laser in real time during the laser scanning process.

[0077] The laser welding device 13 includes a laser welding head and a laser.

[0078] The laser is mounted on the laser welding head and is used to emit a laser beam. The laser may be an Apache 6000W fiber laser. In other implementations, the laser may also be other types of lasers. This embodiment does not limit the type of laser.

[0079] The laser welding head has an oscillating tracking device to achieve a scanning function. The laser welding head can be a Precision YW52 laser welding head equipped with an oscillating tracking device. The maximum scanning frequency of this laser welding head can reach 500 Hz. In other embodiments, the laser welding head can also be other types of laser welding heads. This embodiment does not limit the type of laser welding head.

[0080] The laser welding head can control the laser output power of the laser at different laser scanning positions in real time. In this case, the laser welding device 13 performs laser scanning in a direction perpendicular to the welding direction during the welding process to weld the overlap joint of the first and second sheets. The laser output power of the laser welding device corresponding to at least two different laser scanning positions is different.

[0081] In one example, control software is embedded within the laser welding head to control the laser power at different laser scanning positions. The control software may be the WeldMaster welding assistance system used in automotive welding processes. In other application scenarios, the control software may also be other software. This embodiment does not limit the implementation of the control software.

[0082] Specifically, the laser welding device 13 is used to obtain the laser output power corresponding to each laser scanning position; wherein, the laser output power corresponding to at least two different laser scanning positions is different; during the welding process, according to the laser output power corresponding to each laser scanning position, the laser scanning is performed in a direction perpendicular to the welding direction to weld the lap joint of the first plate 14 and the second plate 15.

[0083] In this embodiment, after welding according to the laser output powers corresponding to at least two different laser scanning positions, the weld between the first plate and the second plate meets the expected welding standard.

[0084] In one example, the desired welding standards include: undercut or collapse of the fillet weld front side is less than a preset threshold; the back side of the first plate 14 is not fully melted; and the second plate 15 is uniformly melted.

[0085] The preset threshold value may be 0.1 mm, or other values ​​set according to the desired welding standard. This embodiment does not limit the value of the preset threshold value.

[0086] In this embodiment, in order to achieve the desired welding standard, a surface focusing method is adopted during welding, that is, the laser focus position is located at the angle between the first plate 14 and the second plate 15 .

[0087] In this embodiment, the laser output power corresponding to each scanning position on the scanning trajectory is determined based on the maximum laser output power; the maximum laser output power is related to the laser welding speed, the thermophysical performance coefficient corresponding to the first plate, and the thickness of the first plate. This ensures that the angle of the first plate 14 is fully welded.

[0088] At this time, the laser welding device 13 obtains the laser output power corresponding to each laser scanning position, including: obtaining the laser welding speed of the laser welding device, the thermal physical performance coefficient corresponding to the first plate and the thickness of the first plate; calculating the maximum laser output power based on the product of the laser welding speed, the thermal physical performance coefficient and the thickness of the first plate; determining the laser output power corresponding to each laser scanning position based on the maximum laser output power.

[0089] In one example, the maximum laser output power is calculated as follows:

[0090] P=k·δ2·v.

[0091] Where P is the maximum laser output power, in W; k is the thermophysical performance coefficient corresponding to the material of the first plate; δ2 is the thickness of the first plate, in mm; v is the laser welding speed, in m / min.

[0092] The specific k value of different materials is determined by preliminary laser welding process tests without swinging. For example, for stainless steel, high-strength steel, and carbon steel, the k value is generally 300-450. For aluminum alloy, the k value is generally 350-500. In actual implementation, the k value can also be in other value ranges. This embodiment does not limit the value of k.

[0093] The thickness of the first plate and the material of the first plate may be input by a user or sent by other devices. This embodiment does not limit the manner in which the laser welding device obtains the thickness of the first plate and the material of the first plate.

[0094] The scanning track of the laser welding device includes a first area located on the first plate and a second area located on the second plate; wherein the first area is located on the upper surface of the first plate; and the second area is located on the side of the second plate.

[0095] The laser output power corresponding to each first laser scanning position is: the product of the first weight corresponding to the first laser scanning position and the maximum laser output power; the first scanning distance of the first laser scanning position is negatively correlated with the first weight.

[0096] The first scanning distance is the distance from the first laser scanning position to the lap joint.

[0097] For example, the first weight of the first laser scanning position with the maximum first scanning distance ranges from [0.1, 0.3]. Accordingly, the laser output power P1 at the first laser scanning position is the product of any value in [0.1, 0.3] and the maximum laser output power.

[0098] For another example, the range of the first weight for the first laser scanning position where the first scanning distance is half of the maximum value is [0.6, 0.8]. Accordingly, the laser output power P2 at the first laser scanning position is the product of any value in [0.6, 0.8] and the maximum laser output power.

[0099] The laser output power corresponding to the third laser scanning position at the lap joint is: the sum of the thickness of the first plate and the thickness of the second plate divided by the thickness of the first plate, multiplied by the third weight and the maximum laser output power.

[0100] For example, the value range of the third weight is [0.4, 0.6]. Correspondingly, the laser output power P3 at the third laser scanning position is Here, (0.4-0.6) represents any value in [0.4, 0.6], δ1 is the thickness of the second plate, δ2 is the thickness of the first plate, and Pmax is the maximum laser output power.

[0101] The laser output power corresponding to each second laser scanning position is: the product of the second weight corresponding to the second laser scanning position, the ratio of the plate thickness and the maximum laser output power; the second scanning distance of the second laser scanning position is negatively correlated with the second weight; the ratio of the plate thickness is the ratio of the thickness of the second plate to the thickness of the first plate.

[0102] The second scanning distance is the distance from the second laser scanning position to the lap joint.

[0103] For example, the range of the second weight for the second laser scanning position where the second scanning distance is half of the maximum value is [0.8, 1.0]. Correspondingly, the laser output power P4 at the second laser scanning position is Wherein, (0.8-1.0) represents any value in [0.8, 1.0], δ1 is the thickness of the second plate, δ2 is the thickness of the first plate, and Pmax is the maximum laser output power.

[0104] For another example, the range of the second weight for the second laser scanning position with the largest second scanning distance is [0.1, 0.3]. Correspondingly, the laser output power P5 at the second laser scanning position is Wherein, (0.1-0.3) represents any value in [0.1, 0.3], δ1 is the thickness of the second plate, δ2 is the thickness of the first plate, and Pmax is the maximum laser output power.

[0105] Optionally, the laser output power between two adjacent laser scanning positions varies uniformly.

[0106] Optionally, the scanning trajectory is a periodic scanning trajectory; the scanning trajectory includes at least two laser scanning positions, and the at least two laser scanning positions are set according to the period of the scanning trajectory.

[0107] The periodic scanning trajectory includes but is not limited to: sinusoidal, elliptical or sawtooth periodic waveforms, refer to Figure 2 The corresponding relationship between each periodic scanning trajectory and the laser output power is shown.

[0108] Figure 2 In this paper, the scanning trajectory of each cycle includes 8 laser scanning positions as an example. Figure 2 It can be seen that the 8 laser scanning positions are divided into equal intervals according to the period of the scanning trajectory, namely, the initial position of the cycle, 1 / 8 cycle position, 2 / 8 cycle position, 3 / 8 cycle position, 4 / 8 cycle position, 5 / 8 cycle position, 6 / 8 cycle position and 7 / 8 cycle position; the laser output power of each laser scanning position can be individually adjusted within the range of 0 to 100% of the maximum laser welding power, and changes evenly between two adjacent laser scanning positions.

[0109] In actual implementation, the scanning trajectory may also include more or fewer laser scanning positions, such as 12 or 16 laser scanning positions. This embodiment does not limit the number of laser scanning positions.

[0110] For a periodic scanning trajectory, the scanning frequency (or scanning period) and trajectory amplitude of the scanning trajectory are pre-set in the laser welding device. For example, the scanning frequency range is 100 to 500 Hz, and the scanning amplitude range is 1 to 2 mm. In actual implementation, the scanning frequency and scanning amplitude range can also be other values. This embodiment does not limit the values ​​of the scanning frequency and scanning range.

[0111] refer to Figure 3 , taking the periodic scanning trajectory as a zigzag shape and each periodic scanning trajectory including 8 laser scanning positions as an example, according to Figure 3 It can be seen that the laser scanning position of each cycle is distributed in the first area 21 of the first plate and the second area 22 of the second plate, and the edge of the first area is scanned on the first plate side ( Figure 3 When the laser output power is set to (0.1-0.3)·Pmax; when the first plate side is scanned to the center area of ​​the first area ( Figure 3 (T1 and T3 points in the middle), set the laser output power to (0.9~1.0)·Pmax; when scanning the lap joint of the first plate and the second plate ( Figure 3 At points T0 and T4 in the middle), set the laser output power to (0.8~1)·(δ1+δ2) / 2δ2·Pmax; when scanning the center area of ​​the second area on the second plate side ( Figure 3 At points T5 and T7 in the middle), set the laser power at the laser power point to (0.9-1.0)·δ1 / δ2·Pmax. When the edge of the second area is scanned to the second plate side ( Figure 3 The laser output power is set to (0.1-0.3)·δ1 / δ2·Pmax.

[0112] Since the second plate 15 needs to be fully welded to achieve the lap joint welding when the laser is projected onto the upper surface of the second plate 15, this will cause the problem of consuming more welding energy. Based on this, in order to avoid the laser being projected onto the upper surface of the second plate 15, such as Figure 4 As shown, the angle α between the laser output axis and the normal of the first plate needs to be set to a preset angle range. The preset angle range can be 0 to 15°. Of course, it can also be other values. This embodiment does not limit the value of the preset angle range.

[0113] The normal line of the first plate is specifically the normal line of the upper surface at the butt joint.

[0114] The angle between the laser output axis and the butt joint surface is biased toward the thin plate (ie, the second plate) side, and the specific angle is positively correlated with the thickness of the second plate.

[0115] In one example, the angle α is determined by the formula α = 10δ1, where the angle α is in degrees and the thickness δ1 of the second plate is in mm. The specific angle can be adjusted within a range of 20% of the calculated value. Of course, the angle deviation range can also be adjusted to other values, such as 10% or 15%. This embodiment limits the angle deviation adjustment method.

[0116] In order to more clearly understand the laser welding system provided by the present application, the working process of the laser welding system is described below with two examples.

[0117] In the first example, it is assumed that the first plate and the second plate are both made of stainless steel, and the thickness of the first plate is 3 mm, and the thickness of the second plate is 1 mm.

[0118] Before welding, first use sandpaper to grind the joint surface and welding area of ​​the plate, and then use alcohol to clean the grinded area.

[0119] According to the angle α determination formula α=10δ1, it is calculated that the angle between the laser output axis and the normal of the first plate is 10°.

[0120] During welding, a surface focusing method is adopted, and the laser focus position is located at the angle between the lap joint of the first plate 14 and the second plate 15 .

[0121] The laser welding speed is selected as 2.4m / min, and the k value of stainless steel is 370 according to the laser welding process test without swinging. Therefore, the maximum laser output power P required for welding is calculated to be 2664W according to the calculation formula P=k·δ2·v.

[0122] During welding, the laser beam is scanned in a sawtooth waveform perpendicular to the welding direction, with a scanning frequency range of 200 Hz and a scanning amplitude range of 2.5 mm. Eight laser power points are set according to time in each scanning cycle.

[0123] When the laser beam is irradiated on the edge of the first plate side scanning the first area ( Figure 3 The laser output power is set to 0.2·P≈533W, and when the first plate side is scanned to the center of the first area ( Figure 3 Set the laser output power to 0.7·P≈1665W and scan to the overlap joint ( Figure 3 At points T0 and T4 in the middle), the laser output power is set to 0.5·(1+3) / 3·P=1776W. When scanning the edge of the second area on the second plate side ( Figure 3 At points T5 and T7 in the middle), set the laser output power to 0.9·1 / 3·P≈799W, and when the edge of the second area is scanned to the second plate side ( Figure 3The laser output power is set to 0.2·1 / 3·P≈178W.

[0124] After welding was completed, the weld formation was inspected and it was found that the undercut and collapse were both less than 0.1mm. In addition, the back of the first plate was not fully welded, and the fillet weld was evenly fused, meeting the expected welding standards. Therefore, the weld was qualified and no process adjustment was required.

[0125] In the second example, it is assumed that the first plate and the second plate are both made of aluminum alloy, and the thickness of the first plate is 3 mm, and the thickness of the second plate is 3 mm.

[0126] Before welding, the plate joint surface and welding area were first polished with sandpaper, and then the polished area was cleaned with alcohol. After that, the oxide film on the surface of the aluminum alloy was pickled with a 10% mass fraction hydrochloric acid solution at 35°C.

[0127] According to the angle α determination formula α=10δ2, the angle between the laser output axis and the butt joint surface of the unequal thickness plate is calculated to be 30°.

[0128] During welding, a surface focusing method is adopted, and the laser focus position is located at the angle between the lap joint of the first plate 14 and the second plate 15 .

[0129] The laser welding speed was selected as 2.0 m / min, and the k value of the aluminum alloy was 420 according to the laser welding process test without swinging. Therefore, the maximum laser output power P required for welding was calculated to be 2520 W according to the calculation formula P=k·δ2·v.

[0130] During welding, the laser beam is scanned in a sawtooth waveform perpendicular to the welding direction, with a scanning frequency range of 250 Hz and a scanning amplitude range of 3 mm; 8 laser power points are set according to time in each scanning cycle.

[0131] When the laser beam is irradiated on the edge of the first plate side scanning the first area ( Figure 3 The laser output power is set to 0.2·P=504W, and when the first plate side is scanned to the center of the first area ( Figure 3 The laser output power is set to 0.7·P≈1764W, and when the laser reaches the lap joint of the first plate and the second plate ( Figure 3 The laser output power is set to 0.5·(3+3) / 3·P=2520W, and when the second plate side is scanned to the center of the second area ( Figure 3 At points T5 and T7 in the middle), set the laser output power to 0.9·3 / 3·P=2268W. When the edge of the second area is scanned to the second plate side ( Figure 3The laser output power was set to 0.2·3 / 3·P=504W.

[0132] After welding was completed, the weld formation was inspected and it was found that the undercut and collapse were both less than 0.1mm. In addition, the back of the first plate was not fully welded, and the fillet weld was evenly fused, meeting the expected welding standards. Therefore, the weld was qualified and no process adjustment was required.

[0133] In summary, the laser welding system provided in this embodiment is provided by setting a workbench; a pad placed on the workbench; during the welding process, a first plate is placed on the workbench, and the thickness of the pad is the same as that of the first plate; a second plate is also placed on the first plate and the pad; a laser welding device with a scanning function performs laser scanning in a direction perpendicular to the welding direction during the welding process to weld the lap joint of the first plate and the second plate; the laser welding device has different laser output powers corresponding to at least two different laser scanning positions; it can solve the problem that when welding lap joints by laser filling wire, the laser welding system has a complex structure, a large laser output power, and severe deformation of the weldment; by controlling the energy distribution of the laser at different positions while laser scanning welding, the metal fusion ratio on both sides of the fillet weld of the lap joint of the metal plates can be controlled, the weld formation can be improved, and the welding quality can be improved. At the same time, there is no need to set up a wire feeding mechanism to achieve high-quality fillet welds, which can reduce the complexity of the laser welding system.

[0134] In addition, by determining the laser output power of each laser scanning position based on the maximum laser output power, the maximum laser power is related to the laser welding speed, the thermal physical performance coefficient corresponding to the first plate, and the thickness of the first plate. Therefore, the laser output power can be adaptively changed according to the plate, welding speed and thickness, thereby improving the flexibility of allocating laser output power.

[0135] In addition, by determining the angle between the laser output axis and the normal vector of the upper surface of the first plate according to the thickness of the second plate, the laser beam can be prevented from irradiating the upper surface of the second plate, thereby increasing the energy required for welding; thereby reducing the energy required for welding.

[0136] Based on the laser welding system of the above embodiment, the laser welding control method provided by the present application is introduced below.

[0137] Figure 5 This is a flow chart of a laser welding control method provided by an embodiment of the present application. Figure 1 Taking the laser welding device 13 in the embodiment as an example, the method includes at least the following steps:

[0138] Step 501 : Obtain the laser output power corresponding to each laser scanning position; wherein the laser output powers corresponding to at least two different laser scanning positions are different.

[0139] Optionally, obtaining the laser output power corresponding to each laser scanning position includes: obtaining the laser welding speed of the laser welding device, the thermophysical performance coefficient corresponding to the first plate and the thickness of the first plate; calculating the maximum laser output power based on the product of the laser welding speed, the thermophysical performance coefficient and the thickness of the first plate; and determining the laser output power corresponding to each laser scanning position based on the maximum laser output power.

[0140] In which, the scanning trajectory of the laser welding device includes a first area located on the first plate and a second area located on the second plate; the laser output power corresponding to each laser scanning position is determined based on the maximum laser output power, including: setting the laser output power corresponding to each first laser scanning position to: the product of the first weight corresponding to the first laser scanning position and the maximum laser output power; the first scanning distance of the first laser scanning position is negatively correlated with the first weight; the first laser scanning position is located in the first area; setting the laser output power corresponding to each second laser scanning position to: the product of the second weight corresponding to the second laser scanning position, the ratio of the plate thickness and the maximum laser output power; the second scanning distance of the second laser scanning position is negatively correlated with the second weight; the ratio of the plate thickness is the ratio of the thickness of the second plate to the thickness of the first plate; the second laser scanning position is located in the second area; setting the laser output power corresponding to each third laser scanning position on the lap joint to: the sum of the thickness of the first plate and the thickness of the second plate divided by the thickness of the first plate, multiplied by the third weight and the maximum laser output power.

[0141] In one example, the scanning trajectory is a periodic scanning trajectory; obtaining the laser output power corresponding to each laser scanning position includes: setting at least two laser scanning positions according to the period of the scanning trajectory; and setting the laser output power corresponding to the at least two laser scanning positions.

[0142] Optionally, determining the laser output power corresponding to each laser scanning position based on the maximum laser output power further includes: setting the laser output power between two adjacent laser scanning positions to vary uniformly.

[0143] Step 502 : During the welding process, laser scanning is performed in a direction perpendicular to the welding direction according to the laser output power corresponding to each laser scanning position to weld the lap joint of the first plate and the second plate.

[0144] Optionally, laser scanning is performed in a direction perpendicular to the welding direction, including: performing laser scanning in a direction perpendicular to the welding direction, including: obtaining the angle between the laser output axis of the laser welding device and the normal of the first plate, the angle being positively correlated with the thickness of the second plate; and performing laser scanning in a direction perpendicular to the welding direction according to the angle.

[0145] For detailed description of this embodiment, please refer to the above system embodiment.

[0146] In summary, the laser welding control method provided in this embodiment obtains the laser output power corresponding to each laser scanning position; wherein, the laser output power corresponding to at least two different laser scanning positions is different; during the welding process, laser scanning is performed in a direction perpendicular to the welding direction according to the laser output power corresponding to each laser scanning position to weld the lap joint of the first plate and the second plate; this method can solve the problem that when welding lap joints by laser filler wire, the laser welding system has a complex structure, the laser output power is large, and the weldment is severely deformed; by controlling the energy distribution of the laser at different positions while laser scanning welding, the metal fusion ratio on both sides of the fillet weld of the lap joint of the metal plates can be controlled, thereby improving the weld formation and the welding quality. At the same time, high-quality fillet welds can be obtained by welding without setting up a wire feeding mechanism, which can reduce the complexity of the laser welding system.

[0147] In addition, by determining the laser output power of each laser scanning position based on the maximum laser output power, the maximum laser power is related to the laser welding speed, the thermal physical performance coefficient corresponding to the first plate, and the thickness of the first plate. Therefore, the laser output power can be adaptively changed according to the plate, welding speed and thickness, thereby improving the flexibility of allocating laser output power.

[0148] In addition, by determining the angle between the laser output axis and the plane where the lap joint is located according to the thickness difference of the plates, the laser beam can be prevented from irradiating the upper surface of the first plate, which would increase the energy required for welding; thereby reducing the energy required for welding.

[0149] Figure 6 FIG. 6 is a block diagram of a laser welding control device provided in an embodiment of the present application. The device includes at least the following modules: a power acquisition module 610 and a laser welding module 620 .

[0150] The power acquisition module 610 is used to acquire the laser output power corresponding to each laser scanning position; wherein the laser output power corresponding to at least two different laser scanning positions is different;

[0151] The laser welding module 620 is used to perform laser scanning in a direction perpendicular to the welding direction according to the laser output power corresponding to each laser scanning position during the welding process to weld the lap joint of the first plate and the second plate.

[0152] For relevant details, please refer to the above method embodiment.

[0153] It should be noted that the laser welding control device provided in the above embodiments is merely an example of the division of the aforementioned functional modules when performing laser welding control. In actual applications, the aforementioned functions can be assigned to different functional modules as needed, that is, the internal structure of the laser welding control device can be divided into different functional modules to perform all or part of the functions described above. Furthermore, the laser welding control device provided in the above embodiments and the laser welding control method embodiment are based on the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0154] Figure 7 FIG. 7 is a block diagram of a laser welding control device provided in one embodiment of the present application. The device includes at least a processor 701 and a memory 702 .

[0155] The processor 701 may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor 701 may be implemented in at least one hardware form of DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), or PLA (Programmable Logic Array). The processor 701 may also include a main processor and a coprocessor. The main processor is a processor for processing data in the awake state, also known as a CPU (Central Processing Unit); the coprocessor is a low-power processor for processing data in the standby state. In some embodiments, the processor 701 may be integrated with a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content to be displayed on the display screen.

[0156] The memory 702 may include one or more computer-readable storage media, which may be non-transitory. The memory 702 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices and flash memory storage devices. In some embodiments, the non-transitory computer-readable storage medium in the memory 702 is used to store at least one instruction, which is executed by the processor 701 to implement the laser welding control method provided in the method embodiment of the present application.

[0157] In some embodiments, the laser welding control device may optionally include a peripheral device interface and at least one peripheral device. The processor 701, memory 702, and peripheral device interface may be connected via a bus or signal lines. Each peripheral device may be connected to the peripheral device interface via a bus, signal lines, or circuit boards. Illustratively, peripheral devices include, but are not limited to, a radio frequency circuit, a touchscreen display, an audio circuit, and a power supply.

[0158] Of course, the laser welding control device may also include fewer or more components, which is not limited in this embodiment.

[0159] Optionally, the present application also provides a computer-readable storage medium, in which a program is stored. The program is loaded and executed by a processor to implement the laser welding control method of the above method embodiment.

[0160] Optionally, the present application also provides a computer product, which includes a computer-readable storage medium, wherein the computer-readable storage medium stores a program, and the program is loaded and executed by a processor to implement the laser welding control method of the above method embodiment.

[0161] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0162] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

[0163] The above is only a specific implementation of the present application. Any other improvements made based on the concept of the present application are considered to be within the scope of protection of the present application.

Claims

1. A laser welding system, characterized in that: The system comprises: Workbench; A backing plate is placed on the workbench; during the welding process, a first plate is placed on the workbench, and the thickness of the backing plate is the same as that of the first plate; a second plate is also placed on the first plate and the backing plate; A laser welding device with a scanning function performs laser scanning in a direction perpendicular to the welding direction during the welding process to weld the overlap joint of the first plate and the second plate; the laser welding device has different laser output powers corresponding to at least two different laser scanning positions; The laser output power corresponding to each scanning position on the scanning trajectory of the laser scanning is determined based on the maximum laser output power; the maximum laser output power is related to the laser welding speed, the thermophysical performance coefficient corresponding to the first plate, and the thickness of the first plate; The scanning track of the laser welding device includes a first area located on the first plate and a second area located on the second plate; The scanning trajectory is a periodic scanning trajectory; the scanning trajectory includes at least two laser scanning positions, and the at least two laser scanning positions are set according to the period of the scanning trajectory; The first laser scanning position is located in the first area, and the second laser scanning position is located in the second area; The laser output power corresponding to each first laser scanning position is: the product of the first weight corresponding to the first laser scanning position and the maximum laser output power; the first scanning distance of the first laser scanning position is negatively correlated with the first weight; the first scanning distance is the distance from the first laser scanning position to the lap joint; The laser output power corresponding to each second laser scanning position is: the product of the second weight corresponding to the second laser scanning position, the plate thickness ratio, and the maximum laser output power; the second scanning distance of the second laser scanning position is negatively correlated with the second weight; the plate thickness ratio is the ratio of the thickness of the second plate to the thickness of the first plate; the second scanning distance is the distance from the second laser scanning position to the lap joint; The laser output power corresponding to the third laser scanning position at the lap joint is: the sum of the thickness of the first plate and the thickness of the second plate divided by the thickness of the first plate, multiplied by the third weight and the maximum laser output power.

2. The system according to claim 1, wherein: After welding according to the laser output powers corresponding to the at least two different laser scanning positions, the fillet weld between the first plate and the second plate meets the expected welding standard.

3. The system according to claim 2, characterized in that The desired welding standards include: The undercut or collapse of the fillet weld front side is less than a preset threshold; The back side of the first plate is not fully melted; and The second sheet material melts evenly.

4. The system according to claim 1, wherein: The laser output power between two adjacent laser scanning positions changes evenly.

5. The system according to any one of claims 1 to 4, characterized in that: The angle between the laser output axis of the laser welding device and the normal line of the first plate is positively correlated with the thickness of the second plate.

6. The system according to any one of claims 1 to 4, characterized in that: The system also includes a first platen and a second platen; The first pressing plate is placed on the first plate to press the first plate; The second pressing plate is placed on the second plate to press the second plate.

7. A laser welding control method, characterized in that: In the system according to any one of claims 1 to 6, the method comprises: Obtaining the laser output power corresponding to each laser scanning position; wherein the laser output powers corresponding to at least two different laser scanning positions are different; During the welding process, laser scanning is performed in a direction perpendicular to the welding direction according to the laser output power corresponding to each laser scanning position to weld the overlap joint of the first plate and the second plate.

8. The method according to claim 7, characterized in that The obtaining of the laser output power corresponding to each laser scanning position includes: Obtaining a laser welding speed of the laser welding device, a thermophysical performance coefficient corresponding to the first plate, and a thickness of the first plate; calculating a maximum laser output power based on a product of the laser welding speed, the thermophysical performance coefficient, and the thickness of the first plate; The laser output power corresponding to each laser scanning position is determined based on the maximum laser output power.

9. The method according to claim 8, characterized in that The determining the laser output power corresponding to each laser scanning position based on the maximum laser output power includes: Set the laser output power between two adjacent laser scanning positions to change uniformly.

10. The method according to claim 8, characterized in that The scanning trajectory of the laser welding device includes a first area located on the first plate and a second area located on the second plate; and determining the laser output power corresponding to each laser scanning position based on the maximum laser output power includes: The laser output power corresponding to each first laser scanning position is set to be: the product of the first weight corresponding to the first laser scanning position and the maximum laser output power; the first scanning distance of the first laser scanning position is negatively correlated with the first weight; the first laser scanning position is located in the first area; The laser output power corresponding to each second laser scanning position is set to be: the product of the second weight corresponding to the second laser scanning position, the plate thickness ratio, and the maximum laser output power; the second scanning distance of the second laser scanning position is negatively correlated with the second weight; the plate thickness ratio is the ratio of the thickness of the second plate to the thickness of the first plate; the second laser scanning position is located in the second area; The laser output power corresponding to each third laser scanning position on the lap joint is set to: the sum of the thickness of the first plate and the thickness of the second plate divided by the thickness of the first plate, multiplied by the third weight and the maximum laser output power.

11. The method according to claim 7, characterized in that The scanning trajectory is a periodic scanning trajectory; and obtaining the laser output power corresponding to each laser scanning position includes: Setting at least two laser scanning positions according to the period of the scanning trajectory; The laser output powers corresponding to the at least two laser scanning positions are set.

12. The method according to claim 7, characterized in that The laser scanning is performed in a direction perpendicular to the welding direction, comprising: Obtaining an angle between a laser output axis of the laser welding device and a normal line of the first plate, wherein the angle is positively correlated with a thickness of the second plate; Laser scanning is performed along a direction perpendicular to the welding direction according to the angle.

13. A laser welding control device, characterized in that: For use in the system according to any one of claims 1 to 6, the device comprises: A power acquisition module is used to acquire the laser output power corresponding to each laser scanning position; wherein the laser output power corresponding to at least two different laser scanning positions is different; The laser welding module is used to perform laser scanning in a direction perpendicular to the welding direction according to the laser output power corresponding to each laser scanning position during the welding process, so as to weld the lap joint of the first plate and the second plate.

14. A laser welding control device, characterized in that: The device includes a processor and a memory; a program is stored in the memory, and the program is loaded and executed by the processor to implement the laser welding control method according to any one of claims 7 to 12.

15. A computer-readable storage medium, characterized in that The storage medium stores a program, which, when executed by a processor, is used to implement the laser welding control method according to any one of claims 7 to 12.

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