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

Abstract

The application relates to a laser welding system, a laser welding control method, a device and a storage medium, and belongs to the technical field of welding. The system comprises a workbench, a backing plate placed on the workbench, the backing plate being used for placing at least two first plates and second plates which are mutually butted, and the first plates and the second plates being of different thicknesses; and a laser welding device with a scanning function, which performs laser scanning along a direction perpendicular to a welding direction in a welding process to weld butt joints of the first plates and the second plates; the laser welding device is different in laser output power corresponding to at least two different laser scanning positions; the problem that, when double-beam laser is used to perform laser welding on plates of different thicknesses, welding defects such as incomplete fusion and pores exist due to the fact that laser energy distribution is not flexible enough can be solved; and high-quality welding of butt joints of plates of different thicknesses can be realized by controlling laser output power of different laser scanning positions while scanning.

Description

Technical Field

[0001] This application relates to a laser welding system, laser welding control method, device and storage medium, belonging to the field of welding technology. Background Technology

[0002] Laser welding (or laser splicing) is a technology that uses a laser heat source to join different types, thicknesses, and sizes of plates into a single sheet. For example, it can be used to weld plates of unequal thickness.

[0003] Because the thicknesses of two plates of unequal thickness differ at the joint, the energy required for melting varies. Therefore, when laser welding two plates of unequal thickness using a constant laser output power, instability in the welding process can occur, resulting in problems such as incomplete fusion on the thicker side and burn-through on the thinner side.

[0004] To control the energy distribution on the thin and thick sides, a typical welding method employs parallel dual-beam laser welding to weld plates of unequal thickness. This increases the energy of the laser beam irradiating the thick plate and decreases the energy of the laser beam irradiating the thin plate, thereby controlling the amount of melting on both sides and improving weld formation.

[0005] However, dual-beam lasers can only distribute laser energy at two points, not throughout the entire welding area. Therefore, when welding plates of unequal thickness using dual-beam lasers, welding defects such as incomplete fusion and porosity still exist. Summary of the Invention

[0006] This application provides a laser welding system, laser welding control method, apparatus, and storage medium, which can solve the problems of welding defects such as incomplete fusion and porosity caused by the inflexible distribution of laser energy when using a dual-beam laser to laser weld plates of unequal thickness. This application provides the following technical solution:

[0007] In a first aspect, a laser welding system is provided, the system comprising:

[0008] Workbench;

[0009] A pad is placed on the workbench, the pad being used to place at least two mating first and second plates, wherein the first and second plates are of unequal thickness;

[0010] A laser welding device with scanning function performs laser scanning in a direction perpendicular to the welding direction during the welding process to weld the joint between the first plate and the second plate; the laser welding device has different laser output power at at least two different laser scanning positions.

[0011] Optionally, after welding according to the laser output power corresponding to the at least two different laser scanning positions, the weld joint between the first plate and the second plate meets a desired welding standard.

[0012] Optionally, the desired welding standard comprises:

[0013] the front face undercut or collapse of the weld joint is less than a preset threshold; and,

[0014] the back face butt joint interface is completely fused.

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

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

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

[0018] the laser output power corresponding to each first laser scanning position is a product of a 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 in a negative correlation relationship with the first weight;

[0019] the laser output power corresponding to each second laser scanning position is a product of a second weight corresponding to the second laser scanning position, a plate thickness ratio, and the maximum laser output power; the second scanning distance of the second laser scanning position is in a negative correlation relationship with the second weight; the plate thickness ratio is a 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 on the butt joint interface is a product of a third weight and the maximum laser output power, after the sum of the thickness of the first plate and the thickness of the second plate is divided by twice the thickness of the first plate.

[0021] Optionally, the scanning track is a periodic scanning track; the scanning track comprises at least two laser scanning positions, and the at least two laser scanning positions are arranged according to a period of the scanning track.

[0022] Optionally, an angle between a laser output axis of the laser welding device and a plane where the butt joint is located is positively correlated with a plate thickness difference; the plate thickness difference is an absolute value of a difference between a thickness of the first plate and a thickness of the second plate.

[0023] Optionally, the backing plate includes a first backing plate and a second backing plate, the first backing plate is used to place the first plate, and the second backing plate is used to place the second plate.

[0024] The first backing plate and the second backing plate have a gap therebetween, and the butt joint of the first plate and the second plate is located in the gap.

[0025] Optionally, the butt joint of the first plate and the second plate is located at a center of the gap.

[0026] Optionally, a thickness of the first backing plate is the same as a thickness of the second backing plate.

[0027] Optionally, the system further includes a first pressing plate and a second pressing plate.

[0028] The first pressing plate is placed on the first plate to press the first plate;

[0029] The second pressing plate is placed on the second plate to press the second plate.

[0030] In a second aspect, a laser welding control method is provided, which is used in the system of the first aspect, and the method includes:

[0031] Obtaining laser output power corresponding to each laser scanning position; wherein laser output powers corresponding to at least two different laser scanning positions are different;

[0032] During the welding process, laser scanning is performed along a direction perpendicular to a welding direction according to the laser output power corresponding to each laser scanning position, so as to weld the butt joint of the first plate and the second plate.

[0033] Optionally, the obtaining of the laser output power corresponding to each laser scanning position includes:

[0034] Obtaining a laser welding speed of the laser welding device, a thermal physical performance coefficient corresponding to the first plate, and a thickness of the first plate; wherein the thickness of the first plate is greater than a thickness of the second plate;

[0035] Calculating a maximum laser output power based on a product of the laser welding speed, the thermal physical performance coefficient, and the thickness of the first plate;

[0036] determine the laser output power corresponding to each laser scanning position based on the maximum laser output power.

[0037] Optionally, the determining the laser output power corresponding to each laser scanning position based on the maximum laser output power comprises:

[0038] uniformly changing the laser output power between two adjacent laser scanning positions.

[0039] Optionally, the scanning track of the laser welding device comprises a first region on the first plate and a second region on the second plate; and the determining the laser output power corresponding to each laser scanning position based on the maximum laser output power comprises:

[0040] setting the laser output power corresponding to each first laser scanning position as a product of a 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 being in a negative correlation with the first weight; and the first laser scanning position being located in the first region.

[0041] setting the laser output power corresponding to each second laser scanning position as a product of a second weight corresponding to the second laser scanning position, a plate thickness ratio and the maximum laser output power; the second scanning distance of the second laser scanning position being in a negative correlation with the second weight; the plate thickness ratio being a ratio of the thickness of the second plate to the thickness of the first plate; and the second laser scanning position being located in the second region.

[0042] setting the laser output power corresponding to each third laser scanning position on the butt joint interface as a product of a third weight and the maximum laser output power, after the sum of the thickness of the first plate and the thickness of the second plate is divided by twice the thickness of the first plate.

[0043] Optionally, the scanning track is a periodic scanning track; and the obtaining the laser output power corresponding to each laser scanning position comprises:

[0044] setting at least two laser scanning positions according to a period of the scanning track;

[0045] setting the laser output power corresponding to the at least two laser scanning positions.

[0046] Optionally, the laser scanning in a direction perpendicular to the welding direction comprises:

[0047] An included angle between a laser output axis of the laser welding device and the butt joint surface is obtained, the included angle being in positive correlation with the plate thickness difference; wherein the butt joint surface is a plane formed by the butt joint interface after the first plate and the second plate are butted; and the plate thickness difference is an absolute value of a difference between the thickness of the first plate and the thickness of the second plate.

[0048] The laser is scanned in a direction perpendicular to the welding direction according to the included angle.

[0049] In a third aspect, a laser welding control device is provided for use in the system of the first aspect, and the device comprises:

[0050] A power acquisition module is configured to acquire 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.

[0051] A laser welding module is configured 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 first plate and the second plate.

[0052] In a fourth aspect, a laser welding control device is provided, and the device comprises a processor and a memory; the memory stores a program, and the program is loaded and executed by the processor to implement the laser welding control method provided in the second aspect.

[0053] In a fifth aspect, a computer readable storage medium is provided, and the storage medium stores a program; when the program is executed by a processor, the program is used to implement the laser welding control method provided in the second aspect.

[0054] The present application has the following beneficial effects: by arranging the workbench, the backing plate placed on the workbench, the backing plate being used to place at least two first plates and second plates butted with each other, and the thickness of the first plates and the second plates being different; and the laser welding device with the scanning function, the laser welding device performing laser scanning in a direction perpendicular to the welding direction during the welding process, so as to weld the butt joint interface of the first plates and the second plates; the laser output power of the laser welding device corresponding to at least two different laser scanning positions being different; the problem of welding defects such as incomplete fusion and pores caused by the insufficient flexibility of the distribution of laser energy when the double-beam laser is used to weld the plates with different thicknesses can be solved; and the laser output power of different laser scanning positions can be controlled while scanning, so as to realize high-quality welding of the butt joint of the plates with different thicknesses.

[0055] 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, so that the laser output power can be adaptively changed according to the differences in the plate, the welding speed and the thickness, and the flexibility of distributing the laser output power is improved.

[0056] In addition, by determining the included angle between the laser output axis and the plane where the butt joint interface is located according to the plate thickness difference, the problem that the laser beam is irradiated to the upper surface of the first plate to increase the energy consumed during welding can be prevented, so that the energy consumed during welding can be reduced.

[0057] The above description is only a summary of the technical scheme of the present application. In order to more clearly understand the technical means of the present application, and to implement the content of the description, the following will be described in detail with the preferred embodiments of the present application and in conjunction with the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0058] Figure 1 is a structural schematic diagram of a laser welding system provided by an embodiment of the present application;

[0059] Figure 2 is a schematic diagram of a periodic scanning track and laser output power provided by an embodiment of the present application;

[0060] Figure 3 is a schematic diagram of a laser scanning position provided by an embodiment of the present application;

[0061] Figure 4 is a schematic diagram of the included angle between the laser output axis and the butt joint surface provided by an embodiment of the present application;

[0062] Figure 5 is a flowchart of a laser welding control method provided by an embodiment of the present application;

[0063] Figure 6 is a block diagram of a laser welding control device provided by an embodiment of the present application;

[0064] Figure 7 is a block diagram of a laser welding control device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0065] The specific embodiments of the present application will be further described in detail below in conjunction with the drawings and examples. The following examples are used to illustrate the present application, but are not used to limit the scope of the present application.

[0066] Firstly, several terms related to the present application are introduced.

[0067] Laser Scanner Welding (LSW): through the laser beam incident on the X, Y axis two mirrors of the scanning galvanometer, the computer controls the angle of the mirror, realizes the arbitrary deflection of the laser beam, makes the laser with certain power density focus on different positions of the workpiece surface, realizes the welding function.

[0068] Negative defocus: the focal plane is below the workpiece, which is negative defocus.

[0069] The laser welding system provided by the present application is described below. Optionally, the application scenario of the laser welding system provided by the present embodiment includes welding of first and second plate materials with different thicknesses. In the present application, the first and second plate materials with different thicknesses refer to that when the first and second plate materials are butted, the thickness of the butted end is different.

[0070] In one scenario, the thickness of the first and second plate materials is greater than 1 millimeter and less than 5 millimeters, the thickness δ1 of the second plate material is less than the thickness δ2 of the first plate material, and δ2 / δ1 is less than a first threshold value, and δ2-δ1 is less than a second threshold value; the materials of the first and second plate materials are the same, and the materials include but are not limited to one of stainless steel, carbon steel, high-strength steel, and aluminum alloy.

[0071] The first threshold value can be 2 or other values, and the second threshold value can be 1.5 millimeters or other values, and the present embodiment does not limit the values of the first and second threshold values.

[0072] In other application scenarios, the laser welding system provided by the present application can also be used to weld first and second plate materials with the same thickness, and the thickness of the first and / or second plate materials can be less than or equal to 1 millimeter or greater than or equal to 5 millimeters, and the materials of the first and second plate materials can also be different, and the present embodiment does not limit the application scenario of the laser welding system.

[0073] Figure 1 is a structural schematic diagram of the laser welding system provided by one embodiment of the present application. According to the present embodiment, the laser welding system includes at least a workbench 11, a backing plate 12, and a laser welding device 13. 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.

[0074] The workbench 11 is used to provide a working area when the laser welding system is working. The workbench 11 is movably or fixedly arranged, and the present embodiment does not limit the implementation manner of the workbench 11.

[0075] To prevent damage to the workbench 11, the backing plate 12 is placed on the workbench 11 when the plate material (or welding sample) to be welded is installed. That is, the backing plate 12 is placed on the workbench 11, and is used to place at least two first and second plate materials that are butted with each other, and the thickness of the first plate material 14 and the second plate material 15 is different.

[0076] Optionally, the gasket 12 is made of copper alloy or other material, and the thickness of the gasket 12 is within a preset thickness range, which can be 5-10 mm, and in other embodiments, the thickness range can be other numerical ranges, and the embodiments are not limited to the material and thickness of the gasket.

[0077] In one example, the gasket 12 includes a first gasket for placing the first plate 14 and a second gasket for placing the second plate 15. The first gasket and the second gasket have a gap therebetween, and the butt joint of the first plate 14 and the second plate 15 is located in the gap. In one implementation, the butt joint of the first plate 14 and the second plate 15 is located at the center of the gap.

[0078] Optionally, the first gasket and the second gasket are of equal thickness, so that the distance between the back of the first plate and the workbench is equal to the distance between the back of the second plate and the workbench. The back of the first plate is the side of the first plate in contact with the first gasket, and the back of the second plate is the side of the second plate in contact with the second gasket.

[0079] In other embodiments, the first gasket and the second gasket can also be set to be of unequal thickness according to requirements, and the embodiments are not limited to the implementation of the thickness of the first gasket and the thickness of the second gasket.

[0080] Optionally, after the butt joint of the first plate 14 and the second plate 15, the butt joint gap and the misalignment amount are less than a desired threshold, which can be 0.1 mm or other numerical values, and the embodiments are not limited to the value of the desired threshold.

[0081] For example, a gap of 20-50 mm is reserved between the first gasket and the second gasket, i.e., the first plate is placed on the first gasket, and the second plate is placed on the second gasket, so that the butt joint of the first plate and the second plate is located at the center of the gap between the two gaskets, and the butt joint gap and the misalignment amount are less than 0.1 mm.

[0082] Optionally, the first plate 14 and the second plate 15 are pretreated before being placed on the gasket 12, and the pretreated plates can consume less energy during laser welding, saving the energy consumed during welding.

[0083] The pre-treatment includes but is not limited to at least one of the following: using a file or sandpaper to polish the butt joint surface and the welding area of the plate, and then cleaning with alcohol or acetone; or, after the foregoing treatment, for the plate of aluminum alloy material, continuing to clean with a solution of nitric acid, hydrochloric acid or acetic acid with a mass concentration of 5% or more in a preset temperature environment to remove the surface oxide film; of course, the pre-treatment mode can also include other modes, which will not be enumerated one by one in this embodiment. The preset temperature environment can be a temperature environment of 30-50℃, and of course, the temperature range of the temperature environment can also be adjusted according to actual needs, and the setting mode of the temperature environment is not limited in this embodiment.

[0084] Optionally, in order to ensure the stability of the first plate and the second plate during welding, after placing the first plate and the second plate on the backing plate, the first pressing plate 16 can be placed on the first plate to press the first plate, and the second pressing plate 17 can be placed on the second plate to press the second plate. At this time, the laser welding system further comprises a first pressing plate 16 and a second pressing plate 17.

[0085] The laser welding device 13 has a scanning function and can adjust the laser output power of the laser in real time during laser scanning.

[0086] The laser welding device 13 comprises a laser welding head and a laser.

[0087] The laser is installed on the laser welding head and is used to emit a laser beam. The laser can be an Apache 6000W fiber laser. In other embodiments, the laser can also be other types of lasers, and the type of the laser is not limited in this embodiment.

[0088] The laser welding head has a swing tracking device to realize the scanning function. The laser welding head can be a Pretec YW52 laser welding head equipped with a swing tracking device, and the maximum scanning frequency of the laser welding head can reach 500Hz. In other embodiments, the laser welding head can also be other types of laser welding heads, and the type of the laser welding head is not limited in this embodiment.

[0089] The laser welding head can control the laser output power of the laser at different laser scanning positions in real time. At this time, the laser welding device 13 performs laser scanning in a direction perpendicular to the welding direction during welding to weld the butt joint interface of the first plate and the second plate. The laser output power corresponding to at least two different laser scanning positions of the laser welding device is different.

[0090] In one example, the laser welding head is embedded with a control software, by which the laser power of the laser at different laser scanning positions is controlled. The control software can be for a WeldMaster welding auxiliary system used in an automobile welding process, and in other application scenarios, the control software can be for other software, and the implementation of the control software is not limited in the embodiment.

[0091] Specifically, the laser welding device 13 is configured to obtain 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; and laser scanning is performed along 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 butt joint of the first plate and the second plate.

[0092] In the embodiment, after welding according to the laser output power corresponding to the at least two different laser scanning positions, the weld between the first plate and the second plate meets the expected welding standard.

[0093] In one example, the expected welding standard includes that the weld front undercut or collapse is less than a preset threshold value; and the weld back butt joint is completely fused.

[0094] Wherein, the preset threshold value can be 0.1 millimeter, or other numerical values set according to the expected welding standard, and the value of the preset threshold value is not limited in the embodiment.

[0095] In the embodiment, the laser output power corresponding to each scanning position on the scanning track 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; wherein the thickness of the first plate is greater than the thickness of the second plate.

[0096] 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; and determining the laser output power corresponding to each laser scanning position based on the maximum laser output power.

[0097] In one example, the calculation formula of the maximum laser output power is represented by the following formula:

[0098] P=k·δ·v.

[0099] In the formula, P is the maximum laser output power, and the unit is W; k is the thermal physical property coefficient corresponding to the material of the first plate; δ is the thickness of the first plate, and the unit is mm; and v is the laser welding speed, and the unit is m / min.

[0100] The specific k value of different materials is determined through previous laser welding process test without swinging, for example, for stainless steel, high-strength steel and carbon steel, the value of k is generally 300-450, and for aluminum alloy, the value of k is generally 350-500, in actual implementation, the value of k can also be in other ranges, and the embodiment does not limit the value of k.

[0101] The thickness of the first plate and the material of the first plate can be input by a user or sent by other equipment, and the embodiment does not limit the way in which the laser welding device obtains the thickness of the first plate and the material of the first plate.

[0102] The scanning track of the laser welding device includes a first area on the first plate and a second area on the second plate; the first area is located on the butt joint surface of the first plate, or on the butt joint surface and the upper surface of the first plate; and the second area is located on the butt joint surface of the second plate and the upper surface of the second plate.

[0103] 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; and the first scanning distance of the first laser scanning position is in a negative correlation with the first weight.

[0104] The first scanning distance is the distance from the first laser scanning position to the butt joint interface.

[0105] For example, the value range of the first weight of the first laser scanning position with the maximum first scanning distance is [0.1, 0.3]. Correspondingly, the laser output power P1 of the first laser scanning position is the product of any value in [0.1, 0.3] and the maximum laser output power.

[0106] For example, the value range of the first weight of the first laser scanning position with the maximum first scanning distance is [0.1, 0.3]. Correspondingly, the laser output power P1 of the first laser scanning position is the product of any value in [0.1, 0.3] and the maximum laser output power.

[0107] The laser output power corresponding to the third laser scanning position on the butt joint interface is the product of the third weight and the maximum laser output power after the sum of the thickness of the first plate and the thickness of the second plate is divided by 2 times the thickness of the first plate.

[0108] For example, the third weight is in the range of [0.8, 1.0]. Correspondingly, the laser output power P3 of the third laser scanning position is wherein (0.8-1) represents any value in the range of [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.

[0109] 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 in a negative correlation with the second weight; and the ratio of the plate thickness is the ratio of the thickness of the second plate to the thickness of the first plate.

[0110] wherein the second scanning distance is the distance from the second laser scanning position to the butt joint interface.

[0111] For example, the second weight of the second laser scanning position with a second scanning distance of half of the maximum value is in the range of [0.9, 1.0]. Correspondingly, the laser output power P4 of the second laser scanning position is wherein (0.9-1.0) represents any value in the range of [0.9, 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.

[0112] For example, the second weight of the second laser scanning position with the maximum second scanning distance is in the range of [0.1, 0.3]. Correspondingly, the laser output power P5 of the second laser scanning position is wherein (0.1-0.3) represents any value in the range of [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.

[0113] Optionally, the laser output power between adjacent two laser scanning positions changes uniformly.

[0114] Optionally, the scanning track is a periodic scanning track; the scanning track includes at least two laser scanning positions, and the at least two laser scanning positions are arranged according to the period of the scanning track.

[0115] wherein the periodic scanning track includes but is not limited to a periodic waveform in a sine shape, an ellipse shape, or a sawtooth shape, and the corresponding relationship between each periodic scanning track and the laser output power is shown in Figure 2 .

[0116] Figure 2 For example, the scanning track of each period includes eight laser scanning positions, and the corresponding relationship between the scanning track and the laser output power is shown in Figure 2It can be seen that the eight laser scanning positions are equally divided according to the period of the scanning trajectory, i.e., at the initial position of the period, the 1 / 8 period position, the 2 / 8 period position, the 3 / 8 period position, the 4 / 8 period position, the 5 / 8 period position, the 6 / 8 period position, and the 7 / 8 period position. The laser output power of each laser scanning position can be individually adjusted within the range of 0-100% of the maximum laser welding power, and uniformly changes between adjacent two laser scanning positions.

[0117] In actual implementation, the scanning trajectory can also include more or fewer laser scanning positions, such as 12 or 16 laser scanning positions, and the number of laser scanning positions is not limited in the embodiment.

[0118] For the periodic scanning trajectory, the scanning frequency (or scanning period) and the trajectory amplitude of the scanning trajectory are pre-set in the laser welding device, such as the scanning frequency range of 100-500 Hz and the scanning amplitude range of 1-2 mm. In actual implementation, the scanning frequency and the scanning amplitude range can also be other values, and the values of the scanning frequency and the scanning range are not limited in the embodiment.

[0119] Reference Figure 3 Taking the periodic scanning trajectory as a sawtooth shape and each period of the scanning trajectory including eight laser scanning positions as an example, according to Figure 3 It can be seen that the laser scanning positions of each period are distributed in the first region 21 of the first plate and the second region 22 of the second plate. When the first plate side scans the edge of the first region (T2 point in Figure 3 ), the laser output power is set to (0.1-0.3)·Pmax; when the first plate side scans to the center region of the first region (T1, T3 points in Figure 3 ), the laser output power is set to (0.9-1.0)·Pmax; when scanning to the butt joint of the first plate and the second plate (T0, T4 points in Figure 3 ), the laser output power is set to (0.8-1)·(δ1+δ2) / 2δ2·Pmax; when the second plate side scans to the center region of the second region (T5, T7 points in Figure 3 ), the laser power of the laser power point is set to (0.9-1.0)·δ1 / δ2·Pmax; and when the second plate side scans to the edge of the second region (T6 point in Figure 4 ), the laser output power is set to (0.1-0.3)·δ1 / δ2·Pmax.

[0120] In order to increase the amount of metal melting on the thick plate (i.e., the first plate) side, such as Figure 4As shown, the angle a between the laser output axis and the butt joint surface (i.e., the plane where the butt joint interface is located) needs to be set within a preset angle range, which can be 0-15°, and of course, can also be other values, and the present embodiment does not limit the value of the preset angle range.

[0121] The angle between the laser output axis and the butt joint surface is biased toward the side of the thin plate (i.e., the second plate), and the specific angle is positively correlated with the thickness difference of the plates. The thickness difference of the plates is the absolute value of the difference between the thickness of the first plate and the thickness of the second plate. In other words, the angle is determined according to the difference Δδ between the thickness of the first plate and the thickness of the second plate.

[0122] In one example, the angle a determination formula is a = 10Δδ, where the angle a is in degrees and the thickness difference Δδ is in mm. The specific angle can be adjusted within a range of 20% of the calculated value, and of course, the angle deviation range can also be adjusted according to other values, such as 10%, 15%, etc., and the present embodiment does not limit the angle deviation adjustment method.

[0123] Optionally, a negative focus method is used during welding, and the laser focal point position is located at a certain distance range below the upper surface of the second plate, which can be 3-8 mm, and of course, the value of the certain distance range can also be changed according to the welding requirements, and the present embodiment does not limit the value of the first distance range.

[0124] In order to more clearly understand the laser welding system provided by the present application, two examples of the working process of the laser welding system are described below.

[0125] 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 1.5 mm and the thickness of the second plate is 1 mm.

[0126] Before welding, first polish the butt joint surface and the welding area of the plates with sandpaper, and then clean the polished area with alcohol.

[0127] Install the first plate and the second plate according to Figure 1 As shown, control the butt joint gap and the misalignment amount of the two plates to be less than 0.1 mm.

[0128] According to the angle a determination formula a = 10Δδ, the angle between the laser output axis and the butt joint surface of the plates is calculated to be 5°.

[0129] During welding, a negative focus method is used, and the focal point is located 3 mm below the upper surface of the second plate.

[0130] The laser welding speed is 2.4 m / min, and the k value of stainless steel obtained by the laser welding process test without swinging is 370, so the maximum laser output power P required for welding is calculated to be 1332 W according to the calculation formula P=k·δ·v.

[0131] During welding, the laser beam is scanned in a sawtooth waveform perpendicular to the welding direction, the scanning frequency ranges from 150 Hz, and the scanning amplitude ranges from 1.2 mm; 8 laser power points are set according to time in each scanning period.

[0132] When the laser beam irradiates the edge of the first area on the first plate side (T2 point in the middle), Figure 3 the laser output power is set to 0.2·P≈266 W, when the first area is scanned to the center on the first plate side (T1, T3 points in the middle), Figure 3 the laser output power is set to 0.95·P≈1265 W, when the butt joint is scanned (T0, T4 points in the middle), Figure 3 the laser output power is set to 0.9·(1+1.5) / (2·1.5)·P≈999 W, when the edge of the second area is scanned on the second plate side (T5, T7 points in the middle), Figure 3 the laser output power is set to 0.95·1 / 1.5·P≈844 W, when the edge of the second area is scanned on the second plate side (T6 point in the middle), Figure 4 the laser output power is set to 0.2·1 / 1.5·P≈178 W.

[0133] After welding, the weld forming is detected, the front forming is measured by a three-dimensional scanner with an accuracy of 0.01 mm, it is found that the undercut and collapse are less than 0.1 mm, in addition, the butt joint at the back of the weld is completely fused, which meets the expected welding standard, so the weld is qualified and does not need to be adjusted again.

[0134] In the second example, it is assumed that the first plate and the second plate are both aluminum alloy materials, and the thickness of the first plate is 2.5 mm and the thickness of the second plate is 1.5 mm.

[0135] Before welding, first, sandpaper is used to polish the butt joint surface and the welding area of the plate, then alcohol is used to clean the polished area, and then a 10% hydrochloric acid solution is used to acid wash the aluminum alloy surface oxide film at 35℃.

[0136] The first plate and the second plate are installed according to Figure 1 The butt joint gap and the misalignment amount of the two plates are controlled to be less than 0.1 mm.

[0137] According to the included angle α determination formula α=10Δδ, the angle between the laser output axis and the butt joint surface of the unequal thickness plate is calculated to be 10°.

[0138] The negative focal length mode is used during welding, so that the focal point is located at the lower part 5 mm below the upper surface of the sheet.

[0139] The laser welding speed is selected as 2.4 m / min, and the k value of the aluminum alloy is 420 according to the laser welding process test without swinging, so that the maximum laser output power P required for welding is calculated as 2520 W according to the calculation formula P=k·δ·v.

[0140] During welding, the laser beam is scanned in a sawtooth waveform along the direction perpendicular to the welding direction, the scanning frequency ranges from 200 Hz, and the scanning amplitude ranges from 1.5 mm; 8 laser power points are set according to time in each scanning period.

[0141] When the laser beam irradiates the edge of the first area on the first plate side (T2 point in the middle), Figure 3 the laser output power is set as 0.2·P=504 W, when the first area is scanned to the center on the first plate side (T1, T3 points in the middle), Figure 3 the laser output power is set as 0.95·P=2394 W, when the butt joint of the first plate and the second plate is scanned (T0, T4 points in the middle), Figure 3 the laser output power is set as 0.9·(1.5+2.5) / (2·2.5)·P≈1814 W, when the second area is scanned to the center on the second plate side (T5, T7 points in the middle), Figure 3 the laser output power is set as 0.95·1.5 / 2.5·P≈1436 W, when the second area is scanned to the edge on the second plate side (T6 point in the middle), Figure 3 the laser output power is set as 0.2·1.5 / 2.5·P≈302 W.

[0142] After the welding is completed, the weld forming is detected, the front forming is measured by a three-dimensional scanner with an accuracy of 0.01 mm, it is found that the undercut and collapse are less than 0.1 mm, in addition, the back interface of the weld is completely fused, which meets the expected welding standard, so the weld is qualified and does not need to be adjusted again.

[0143] In summary, the laser welding system provided in the embodiment can solve the problem of welding defects such as incomplete fusion and pores in the welding process of the unequal-thickness plates by using a double-beam laser, because the distribution of laser energy is not flexible enough. The laser output power of the laser welding device at different laser scanning positions can be controlled to achieve high-quality welding of the unequal-thickness plate butt joint.

[0144] In addition, the laser output power of each laser scanning position is determined based on the maximum laser output power, which 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 differences in the plate, the welding speed, and the thickness, thereby improving the flexibility of the distribution of the laser output power.

[0145] In addition, by determining the included angle between the laser output axis and the plane where the butt joint interface is located according to the thickness difference of the plate, the problem of increasing the energy consumed during welding caused by the laser beam irradiating the upper surface of the first plate can be prevented. Therefore, the energy consumed during welding can be reduced.

[0146] Based on the laser welding system described in the above embodiment, the laser welding control method provided in the present application is introduced as follows.

[0147] Figure 5 is a flowchart of the laser welding control method provided in an embodiment of the present application. The embodiment takes the laser welding device 13 in the laser welding system 1 as an example to illustrate the method, which includes at least the following steps: Figure 1

[0148] Step 501: 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.

[0149] Optionally, obtaining the laser output power corresponding to each laser scanning position includes: 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; wherein the thickness of the first plate is greater than the thickness of the second 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; and determining the laser output power corresponding to each laser scanning position based on the maximum laser output power. ​

[0150] The scanning trajectory of the laser welding device comprises a first region on the first plate and a second region on the second plate; the laser output power corresponding to each laser scanning position is determined based on the maximum laser output power, which comprises: setting the laser output power corresponding to each first laser scanning position as 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 in a negative correlation with the first weight; the first laser scanning position is located in the first region; setting the laser output power corresponding to each second laser scanning position as the product of the second weight corresponding to the second laser scanning position, the ratio of the thickness of the plate, and the maximum laser output power; the second scanning distance of the second laser scanning position is in a negative correlation with the second weight; the ratio of the thickness of the plate 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 region; setting the laser output power corresponding to each third laser scanning position on the butt joint interface as the product of the third weight and the maximum laser output power after the sum of the thickness of the first plate and the thickness of the second plate is divided by twice the thickness of the first plate.

[0151] In one example, the scanning trajectory is a periodic scanning trajectory; the laser output power corresponding to each laser scanning position is obtained, which comprises: 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.

[0152] Optionally, the laser output power corresponding to each laser scanning position is determined based on the maximum laser output power, which further comprises: setting the laser output power between adjacent two laser scanning positions to change uniformly.

[0153] Step 502, in the welding process, laser scanning is performed along a direction perpendicular to the welding direction according to the laser output power corresponding to each laser scanning position, so as to weld the butt joint interface of the first plate and the second plate.

[0154] Optionally, the laser scanning along the direction perpendicular to the welding direction comprises: obtaining an included angle between the laser output axis of the laser welding device and the butt joint surface, the included angle being in a positive correlation with the plate thickness difference; wherein the butt joint surface is a plane formed by the butt joint interface after the first plate and the second plate are butted; the plate thickness difference is the absolute value of the difference between the thickness of the first plate and the thickness of the second plate; and the laser scanning is performed along the direction perpendicular to the welding direction according to the included angle.

[0155] The related description of the embodiment is described in the above system embodiment.

[0156] In summary, the laser welding control method provided in the embodiment can solve the problem of welding defects such as incomplete fusion and pores when using a double-beam laser to perform laser welding on unequal-thickness plates, because the distribution of laser energy is not flexible enough, and can control the laser output power of different laser scanning positions while scanning to achieve high-quality welding of unequal-thickness plate butt joints.

[0157] 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, so that the laser output power can be adaptively changed according to the differences in the plate, the welding speed and the thickness, and the flexibility of distributing the laser output power is improved.

[0158] In addition, by determining the included angle between the laser output axis and the plane where the butt joint is located according to the plate thickness difference, the problem of increasing the energy consumed during welding caused by the laser beam irradiating the upper surface of the first plate can be prevented, so that the energy consumed during welding can be reduced.

[0159] Figure 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.

[0160] The power acquisition module 610 is configured 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;

[0161] The laser welding module 620 is configured to perform laser scanning along 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 first plate and the second plate.

[0162] For related details, refer to the above method embodiments.

[0163] It should be noted that the laser welding control device provided in the above embodiments is only used for illustrating the division of the above functional modules when performing laser welding control, and in actual application, the above functions can be distributed to different functional modules according to needs, that is, the internal structure of the laser welding control device is divided into different functional modules to complete all or part of the functions described above. In addition, the laser welding control device and the laser welding control method provided in the above embodiments belong to the same concept, and the specific implementation process is detailed in the method embodiments, which will not be repeated here.

[0164] Figure 7 is a block diagram of the laser welding control device provided in an embodiment of the present application. The device at least includes a processor 701 and a memory 702.

[0165] The processor 701 can include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor 701 can be implemented in at least one of a hardware form of a DSP (Digital Signal Processing), an FPGA (Field-Programmable Gate Array), and a PLA (Programmable Logic Array). The processor 701 can also include a main processor and a coprocessor. The main processor is a processor for processing data in an awake state, also known as a CPU (Central Processing Unit). The coprocessor is a low-power processor for processing data in a standby state. In some embodiments, the processor 701 can be integrated with a GPU (Graphics Processing Unit) that is responsible for rendering and drawing the content to be displayed on the display screen.

[0166] The memory 702 can include one or more computer-readable storage media, which can be non-transitory. The memory 702 can also include a high-speed random access memory and a non-volatile memory such as one or more disk storage devices, flash storage devices. In some embodiments, the non-transitory computer-readable storage medium in the memory 702 is used to store at least one instruction for being executed by the processor 701 to implement the laser welding control method provided in the method embodiments of the present application.

[0167] In some embodiments, the laser welding control device can further optionally comprise a peripheral device interface and at least one peripheral device. The processor 701, the memory 702 and the peripheral device interface can be connected through a bus or a signal line. Each peripheral device can be connected to the peripheral device interface through a bus, a signal line or a circuit board. Illustratively, the peripheral device includes, but is not limited to, a radio frequency circuit, a touch display screen, an audio circuit, a power supply and the like.

[0168] Of course, the laser welding control device can further comprise less or more components, and the present embodiment is not limited thereto.

[0169] Optionally, the present application further provides a computer readable storage medium, wherein a program is stored in the computer readable storage medium, and the program is loaded and executed by a processor to implement the laser welding control method of the method embodiment.

[0170] Optionally, the present application further provides a computer product, which comprises a computer readable storage medium, wherein a program is stored in the computer readable storage medium, and the program is loaded and executed by a processor to implement the laser welding control method of the method embodiment.

[0171] Each technical feature of the above-described embodiments can be combined arbitrarily, and to make the description concise, each technical feature of the above-described embodiments is not described in all possible combinations, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0172] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

[0173] The above is only one specific implementation manner of the present application, and any improvement made on the basis of the concept of the present application is considered as the protection scope of the present application.

[0173]

Claims

1. A laser welding system, characterized in that, The system includes: Workbench; A pad is placed on the workbench, the pad being used to place at least two mating first and second plates, wherein the first and second plates are of unequal thickness; A laser welding device with scanning function performs laser scanning in a direction perpendicular to the welding direction during the welding process to weld the joint between the first plate and the second plate; the laser welding device has different laser output power at at least two different laser scanning positions; The laser output power corresponding to each scanning position on the laser 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 property coefficient corresponding to the first plate, and the thickness of the first plate; wherein, the thickness of the first plate is greater than the thickness of the second plate; The scanning trajectory of the laser welding device includes a first region located on the first plate and a second region located on the second plate; 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 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; The laser output power corresponding to the third laser scanning position on the docking interface is: the sum of the thickness of the first plate and the thickness of the second plate divided by twice the thickness of the first plate, multiplied by the third weight and the maximum laser output power. The laser output power P1 corresponding to the first laser scanning position is calculated using formula 1: Formula 1: P1 = a1·Pmax; Where a1 represents the first weight and Pmax is the maximum laser output power; The laser output power P4 corresponding to the second laser scanning position is calculated using formula 2: Formula 2: P4 = a2·δ1 / δ2·Pmax; Where a2 represents the second weight, δ1 represents the thickness of the second plate, δ2 represents the thickness of the first plate, and Pmax is the maximum laser output power; the laser output power P3 corresponding to the third laser scanning position is calculated using formula 3: Formula 3: P3 = a3·(δ1+δ2) / 2δ2·Pmax; Where a3 represents the third weight, δ1 represents the thickness of the second plate, δ2 represents the thickness of the first plate, and Pmax is the maximum laser output power.

2. The system according to claim 1, characterized in that, After welding according to the laser output power corresponding to at least two different laser scanning positions, the 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 on the weld face is less than a preset threshold; and... The weld seam is completely fused at the back joint.

4. The system according to claim 1, characterized in that, The laser output power varies uniformly between two adjacent laser scanning positions.

5. The system according to claim 1, characterized in that, The scanning trajectory is a periodic scanning trajectory; the scanning trajectory includes at least two laser scanning positions, which are set according to the period of the scanning trajectory.

6. The system according to any one of claims 1 to 5, characterized in that, The angle between the laser output axis of the laser welding device and the plane where the docking interface is located is positively correlated with the thickness difference of the plates; the thickness difference of the plates is the absolute value of the difference between the thickness of the first plate and the thickness of the second plate.

7. The system according to any one of claims 1 to 5, characterized in that, The pad includes a first pad and a second pad, wherein the first pad is used to place the first material and the second pad is used to place the second material; There is a gap between the first pad and the second pad, and the mating interface between the first plate and the second plate is located within the gap.

8. The system according to claim 7, characterized in that, The mating interface between the first plate and the second plate is located at the center of the gap.

9. The system according to claim 7, characterized in that, The thickness of the first pad is the same as the thickness of the second pad.

10. The system according to any one of claims 1 to 5, characterized in that, The system also includes a first pressure plate and a second pressure plate; The first pressure plate is placed on the first plate to press the first plate firmly; The second pressure plate is placed on the second plate to press the second plate tightly.

11. A laser welding control method, characterized in that, In the system according to any one of claims 1 to 10, the method comprises: Obtain the laser output power corresponding to each laser scanning position; wherein, at least two different laser scanning positions correspond to different laser output powers. 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, so as to weld the joint between the first plate and the second plate.

12. The method according to claim 11, characterized in that, The step of obtaining the laser output power corresponding to each laser scanning position includes: The laser welding speed of the laser welding device, the thermophysical property coefficient of the first plate, and the thickness of the first plate are obtained; wherein the thickness of the first plate is greater than the thickness of the second plate. The maximum laser output power is calculated based on the product of the laser welding speed, the thermophysical property 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.

13. The method according to claim 12, characterized in that, Determining the laser output power corresponding to each laser scanning position based on the maximum laser output power includes: The laser output power is set to vary uniformly between two adjacent laser scanning positions.

14. The method according to claim 12, characterized in that, The scanning trajectory of the laser welding device includes a first region located on the first plate and a second region located on the second plate; 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 as: 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 region; The laser output power corresponding to each second laser scanning position is set as: 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 region; The laser output power corresponding to each third laser scanning position on the docking interface is set as: the sum of the thickness of the first plate and the thickness of the second plate divided by twice the thickness of the first plate, multiplied by the third weight and the maximum laser output power.

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

16. The method according to claim 12, characterized in that, The laser scanning along a direction perpendicular to the welding direction includes: The angle between the laser output axis of the laser welding device and the mating surface is obtained, and the angle is positively correlated with the thickness difference of the plates; wherein, the mating surface is the plane formed by the mating interface after the first plate and the second plate are mated; the thickness difference of the plates is the absolute value of the difference between the thickness of the first plate and the thickness of the second plate; Laser scanning is performed along the angle perpendicular to the welding direction.

17. A laser welding control device, characterized in that, For use in any one of claims 1 to 10, the device comprises: A power acquisition module is used to acquire the laser output power corresponding to each laser scanning position; wherein, at least two different laser scanning positions correspond to different laser output powers. 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 first plate and the second plate.

18. A laser welding control device, characterized in that, The device includes a processor and a memory; the memory stores a program that is loaded and executed by the processor to implement the laser welding control method as described in any one of claims 11 to 16.

19. A computer-readable storage medium, characterized in that, The storage medium stores a program that, when executed by a processor, is used to implement the laser welding control method as described in any one of claims 11 to 16.

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