Modular based co-linear laser welding station and method of controlling the same

Abstract

The present application relates to the technical field of laser welding, and particularly relates to a collinear laser welding workstation based on modularization and a control method thereof, which comprises a base, a position moving unit used for carrying and moving aluminum plate to be welded, a laser welding unit used for emitting laser to a welding interface of the aluminum plate to form a molten pool, a monitoring unit used for monitoring the area of the welding interface, the burr quantity of the molten pool and the vibration intensity of the aluminum plate, and a control unit used for controlling the position moving unit and the laser welding unit to perform a welding test, and adjusting the laser welding temperature of the laser welding unit according to the area variation of the welding interface in the welding test, or correcting the target area of the welding interface according to the burr quantity of the molten pool, and adjusting the laser emission power according to the vibration intensity of the aluminum plate. The present application realizes the improvement of welding stability.

Description

Technical Field

[0001] This invention relates to the field of laser welding technology, and in particular to a modular collinear laser welding workstation and its control method. Background Technology

[0002] In existing technologies, modular collinear laser welding workstations adapt to the needs of large-scale and multi-variety production in the manufacturing industry. They break down functions such as welding, loading and unloading, and inspection into independent modules, and achieve flexible configuration through module combination. The collinear mode requires the workstation to be synchronized with the production line to achieve continuous operation and improve efficiency. The module collaboration is achieved by using distributed control or PLC combined with industrial bus, while the welding quality is guaranteed by real-time monitoring through sensors and vision systems.

[0003] Chinese Patent Publication No. CN119525718A discloses a laser welding workstation, comprising: at least two clamping platforms; a multi-axis robotic arm assembly, including a multi-axis robotic arm and a clamping mechanism, the clamping mechanism including a clamping base plate and at least two clamping units, each clamping base plate having clamping units at both ends, and each clamping unit having an anti-drop unit; a laser welding assembly including a displacement mechanism and a laser welding mechanism, the laser welding mechanism being mounted on a laser support, the displacement mechanism including a first flipping drive, a first flipping frame, a second flipping drive, and a flipping mounting frame, the power output end of the first flipping drive being connected to the first flipping frame to control the first flipping frame to rotate in a first direction; the second flipping drive being mounted on the first flipping frame; the flipping mounting frame being mounted inside the first flipping frame and being driven by the second flipping drive to flip in a second direction; the laser welding assembly and the clamping platforms being located on opposite sides of the multi-axis robotic arm assembly; and a Y-axis moving assembly, the Y-axis moving assembly being used to move the displacement mechanism to below the laser welding mechanism. It can be seen that the laser welding workstation has the problem that when the rapid thermal expansion and contraction of the laser welding molten pool generates thermal stress that is transferred to the aluminum plate, the weld joint is stretched or squeezed to expand its area. As a result, the molten pool has more space to flow to both sides, causing irregular edges and burrs. Consequently, the actual laser energy density acting on the material in the space where the burrs are generated changes, leading to deviations in heating temperature. Summary of the Invention

[0004] To address this issue, the present invention provides a modular collinear laser welding workstation and its control method to overcome the problem in the prior art where the rapid thermal expansion and contraction of the laser welding molten pool generates thermal stress that is transferred to the aluminum plate, causing the weld joint to be stretched or squeezed to expand its area. This results in more space for the molten pool to flow to both sides, causing irregular edges and burrs on the molten pool. Consequently, the actual laser energy density acting on the material in the space where the burrs are generated changes, leading to heating temperature deviations.

[0005] To achieve the above objectives, the present invention provides a modular collinear laser welding workstation, comprising:

[0006] Base;

[0007] A position moving unit, which is connected to the base, is used to carry and move the aluminum sheet to be welded;

[0008] A laser welding unit is disposed above the position moving unit and is used to emit a laser to the weld joint of the aluminum sheet to form a molten pool.

[0009] A monitoring unit, connected to the base, is used to monitor the area of ​​the weld joint, the number of burrs in the molten pool, and the vibration intensity of the aluminum plate.

[0010] The control unit is connected to the position moving unit, the laser welding unit, and the monitoring unit respectively. It is used to control the position moving unit and the laser welding unit to perform welding tests, adjust the laser welding temperature of the laser welding unit according to the change in the area of ​​the weld joint in the welding test, or correct the target area of ​​the weld joint according to the number of burrs in the molten pool, and adjust the laser emission power according to the vibration intensity of the aluminum plate.

[0011] Furthermore, it also includes:

[0012] A preheating unit, which is connected to the position moving unit, is used to preheat the area of ​​the aluminum sheet to be welded.

[0013] A cooling unit, connected to the laser welding unit, is used to cool the welded areas of the aluminum sheet.

[0014] Furthermore, the monitoring unit includes:

[0015] A vision sensor, positioned above the base, acquires images of the weld joint to obtain the area of ​​the weld joint and the number of burrs in the molten pool.

[0016] A vibration sensor, positioned below the vision sensor, is used to detect the vibration intensity of the aluminum sheet.

[0017] Furthermore, the control unit is connected to the vision sensor to acquire the weld joint image, and to segment the weld joint outline and molten pool edge of the aluminum plate respectively, and to calculate the area of ​​the weld joint based on the segmented weld joint outline, and to identify burrs based on the segmented molten pool edge.

[0018] Furthermore, the control unit is connected to the vision sensor and the laser welding unit respectively to obtain the area of ​​the weld joint and calculate the change in the area of ​​the weld joint. If the change in area is greater than or equal to a preset second change, the laser welding temperature is reduced.

[0019] Furthermore, the area change is the absolute value of the difference between the area of ​​the weld joint in the weld joint image collected at the end of the unit monitoring time and the area of ​​the weld joint at the beginning of the unit monitoring time.

[0020] Furthermore, the control unit is connected to the vision sensor to obtain the number of burrs in the molten pool under the condition that the area change is greater than or equal to a preset first change and less than the preset second change. If the number of burrs is greater than or equal to a preset number, the area of ​​the weld joint is increased as a correction area.

[0021] Furthermore, the control unit is connected to the vibration sensor and the laser welding unit respectively to obtain the vibration intensity of the aluminum plate. If the vibration intensity is greater than or equal to the preset vibration intensity, the laser emission power is increased.

[0022] Furthermore, the laser welding unit includes:

[0023] A laser emitter, connected to the base, is used to emit a laser at the weld joint of the aluminum sheet;

[0024] A robotic arm, connected to the laser emitter, is used to adjust the position of the laser emitter.

[0025] This invention also provides a control method for a modular collinear laser welding workstation, comprising:

[0026] Move the aluminum sheet to be welded to the welding position;

[0027] Preheat the aluminum sheet to be welded;

[0028] Welding tests were conducted on aluminum sheets using laser emission to form a molten pool on the sheets.

[0029] The area of ​​the weld joint and the burrs in the molten pool of the aluminum sheet were inspected separately.

[0030] The vibration intensity of the aluminum plate is determined based on the change in the area of ​​the weld joint, and the laser welding temperature is adjusted accordingly, or the target area of ​​the weld joint is corrected based on the number of burrs.

[0031] The laser emission power is adjusted according to the vibration intensity of the aluminum plate;

[0032] According to the laser welding temperature or the target area of ​​the weld joint, the aluminum sheet is actually welded according to the laser emission power to obtain the welded aluminum sheet.

[0033] The welded aluminum sheet is cooled to obtain the finished welded aluminum sheet.

[0034] Compared with existing technologies, the beneficial effects of this invention are that the workstation described in this invention, by setting up a position movement unit, a laser welding unit, a monitoring unit, and a control unit, achieves precise clamping, stable movement, and high-precision laser welding of aluminum plates, forming a welding system integrating motion control, thermal process regulation, and dynamic compensation. Because the molten pool generates significant thermal stress during the rapid heating and cooling cycle in the laser welding process, this stress is transmitted along the weld direction to the base material, causing micro-scale deformation in the weld area. This manifests as the weld being expanded by thermal expansion or squeezed together by cold contraction, thereby increasing the actual molten area. Under the influence of surface tension and flow inertia, the molten pool metal expands asymmetrically to both sides, causing irregularities at the edge of the molten pool and forming defects such as burrs. The presence of burrs alters the local beam absorptivity and energy distribution space, reducing and unevenly distributing the effective laser energy density acting on the material, leading to deviations in the heating temperature field, and ultimately affecting the weld formation quality and joint mechanical properties. By introducing a collaborative detection mechanism of visual and vibration sensors, combined with a dynamic adjustment strategy of welding parameters by the control unit, the instability of the molten pool caused by weld deformation is effectively suppressed, thereby improving the consistency of weld formation.

[0035] Furthermore, the workstation described in this invention is equipped with a preheating unit and a cooling unit. The preheating unit uniformly heats the area to be welded before laser welding, reducing the thermal shock gradient during welding, alleviating the problem of thermal stress concentration caused by localized severe temperature rise, and reducing the tendency of geometric deformation in the weld area caused by thermal expansion and contraction. The cooling unit implements controlled cooling of the welded area after welding, avoiding the continuous diffusion of residual heat after welding that could cause secondary microstructure evolution or deformation, thereby improving the uniformity of the weld joint structure and the dimensional stability.

[0036] Furthermore, the workstation described in this invention acquires weld joint images by setting up a visual sensor, and the control unit segments and extracts features from the weld joint outline and the edge of the molten pool in the image, accurately calculates the weld joint area and its change, and when the change in weld joint area within a unit monitoring time is greater than or equal to a preset second change, it is determined that the weld joint is in a state of significant expansion, and the control unit automatically lowers the laser welding temperature to reduce the input heat energy, suppress excessive melting and lateral flow of metal, and prevent the molten pool from spreading and forming irregular boundaries.

[0037] Furthermore, the workstation described in this invention acquires information about the edge of the molten pool, identifies and counts the number of burrs. If the number of burrs exceeds a preset number, it is determined that the current edge disturbance of the molten pool is serious, and there is a risk of local energy focusing or flow turbulence. By increasing the target area of ​​the weld joint as a correction value, a reasonable melting space is reserved to accommodate the possible overflow of metal fluid, thereby reducing the probability of burr generation and improving the stability of the molten pool.

[0038] Furthermore, the workstation described in this invention monitors the structural vibration intensity of the aluminum sheet in real time during the welding process by setting up vibration sensors. Due to the high thermal conductivity and large coefficient of thermal expansion of aluminum, the sheet is prone to overall or local vibration due to transient thermal stress during laser scanning, which affects the relative positioning accuracy between the laser beam and the weld, and may even cause problems such as molten pool oscillation and porosity inclusions. By increasing the laser emission power, the single-point action time is shortened, the melting and solidification speed is accelerated, and the window period of vibration on molten pool formation is reduced. At the same time, the high-power short pulse mode helps to improve energy density, enhance penetration ability, and counteract the energy dispersion effect caused by vibration, thereby improving the stability of welding. Attached Figure Description

[0039] Figure 1 This is a block diagram of the overall structure of a modular collinear laser welding workstation according to an embodiment of the present invention.

[0040] Figure 2 This is a schematic diagram of the overall structure of a modular collinear laser welding workstation according to an embodiment of the present invention;

[0041] Figure 3 This is a block diagram illustrating the connection structure between the monitoring unit and the control unit of a modular collinear laser welding workstation according to an embodiment of the present invention.

[0042] Figure 4 This is a flowchart of the control method for a modular collinear laser welding workstation according to an embodiment of the present invention;

[0043] The following are the symbols and their meanings: 1-robotic arm, 2-vision sensor, 3-linear module, 4-base, 5-laser emitter, 6-linear guide rail. Detailed Implementation

[0044] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0045] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0046] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0047] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0048] Please see Figure 1 , Figure 2 , Figure 3 as well as Figure 4 The figures shown are, respectively, an overall structural block diagram, an overall structural schematic diagram, a connection structure block diagram of the monitoring unit and the control unit, and a control method flowchart of a modular collinear laser welding workstation according to an embodiment of the present invention. The present invention provides a modular collinear laser welding workstation, comprising:

[0049] Base 4;

[0050] A position moving unit, which is connected to the base 4, is used to support and move the aluminum plate to be welded;

[0051] A laser welding unit is disposed above the position moving unit and is used to emit a laser to the weld joint of the aluminum sheet to form a molten pool.

[0052] A monitoring unit, which is connected to the position moving unit, is used to monitor the area of ​​the weld joint, the number of burrs in the molten pool, and the vibration intensity of the aluminum plate.

[0053] The control unit is connected to the position moving unit, the laser welding unit, and the monitoring unit respectively. It is used to control the position moving unit and the laser welding unit to perform welding tests, adjust the laser welding temperature of the laser welding unit according to the change in the area of ​​the weld joint in the welding test, or correct the target area of ​​the weld joint according to the number of burrs in the molten pool, and adjust the laser emission power according to the vibration intensity of the aluminum plate.

[0054] In this embodiment, collinear laser welding is achieved by having the incident direction of the laser beam, the orientation of the weld joint of the plates to be welded, and the observation direction of the vision sensor 2 in the monitoring unit all in the same vertical plane, thus enabling coaxial monitoring of laser energy and the welding process.

[0055] Specifically, the welding test involves the laser welding unit performing a short-distance weld of 20mm at a power of 2kW and a welding speed of 3m / min 10mm in front of the starting end of the formal weld on the plate to be welded before the actual welding begins.

[0056] Specifically, during the welding process, the number of protrusions that exceed the normal weld contour formed by molten metal solidifying at the edge of the weld pool due to splashing, unstable flow, or gas escape is recorded as the number of burrs.

[0057] Specifically, the target area of ​​the weld joint is the theoretical fusion zone area. For example, for a 3mm thick 6061 aluminum alloy sheet, when using butt welding, the initial theoretical fusion zone area is set to 8.5mm. 2 .

[0058] Specifically, the base 4 adopts a heavy-duty welded frame structure, and the upper surface is covered with linear guide rails 6.

[0059] The position movement unit includes two servo motor driven linear modules 3, which are arranged in a cross shape on the linear guide rails 6 of the base 4; pneumatic clamps or vacuum clamps for fixing aluminum plates of different sizes to be welded are installed above the linear modules 3.

[0060] In practice, the workstation described in this invention, by setting up a position movement unit, a laser welding unit, a monitoring unit, and a control unit, achieves precise clamping, stable movement, and high-precision laser welding of aluminum plates, forming a welding system integrating motion control, thermal process regulation, and dynamic compensation. During laser welding, the molten pool generates significant thermal stress under rapid heating and cooling cycles. This stress is transmitted along the weld direction to the base material, causing microscale deformation in the weld area. This manifests as the weld being expanded by thermal expansion or squeezed by cold contraction, thereby increasing the actual molten area. This causes the molten pool metal to expand asymmetrically to both sides under the action of surface tension and flow inertia, resulting in irregular edges and burrs, among other forming defects. The presence of burrs alters the local beam absorption rate and energy distribution space, reducing and unevenly distributing the effective laser energy density acting on the material, leading to deviations in the heating temperature field, ultimately affecting the weld formation quality and joint mechanical properties. By introducing a collaborative detection mechanism between a visual sensor 2 and a vibration sensor, combined with the control unit's dynamic adjustment strategy for welding parameters, the instability of the molten pool caused by weld deformation is effectively suppressed, improving the consistency of weld formation.

[0061] Specifically, it also includes:

[0062] A preheating unit, which is connected to the position moving unit, is used to preheat the area of ​​the aluminum sheet to be welded.

[0063] A cooling unit, connected to the laser welding unit, is used to cool the welded areas of the aluminum sheet.

[0064] In practice, the preheating unit uses an infrared heater to scan and preheat the preset weld path before welding; the cooling unit includes a compressed air nozzle and a circulating water cooling pipeline. After welding, the compressed air nozzle rapidly cools the weld area at a pressure of 0.6 MPa. The circulating water cooling pipeline, through a cooling channel integrated with the welding head, flows cooling water near the welding area.

[0065] In practice, the workstation described in this invention is equipped with a preheating unit and a cooling unit. The preheating unit uniformly heats the area to be welded before laser welding, reducing the thermal shock gradient during welding, alleviating the problem of thermal stress concentration caused by localized severe temperature rise, and reducing the tendency of geometric deformation in the weld area caused by thermal expansion and contraction. The cooling unit implements controlled cooling of the welded area after welding, avoiding the continuous diffusion of residual heat after welding that could cause secondary microstructure evolution or deformation, thereby improving the uniformity of the weld joint structure and the dimensional stability.

[0066] Specifically, the monitoring unit includes:

[0067] A vision sensor 2 is positioned above the base 4 to acquire images of the weld joint to obtain the area of ​​the weld joint and the number of burrs in the molten pool.

[0068] A vibration sensor, positioned below the vision sensor 2, is used to detect the vibration intensity of the aluminum sheet.

[0069] Specifically, vision sensor 2 uses a high-speed industrial camera, with the camera's optical axis collinear with the laser beam axis;

[0070] The vibration sensor uses a Doppler vibrator, with the probe of the Doppler vibrator pointing vertically to the surface of the non-welded area of ​​the aluminum sheet, and the sampling frequency is set to 10kHz.

[0071] Specifically, the welding process involves the control unit moving the aluminum plate to be welded to the welding position and fixing it with a pneumatic clamp. The preheating unit is activated to preheat the area of ​​the aluminum plate to be welded. After preheating, the laser welding unit emits a test laser to perform a welding test, forming a molten pool on the aluminum plate. The vision sensor 2 and vibration sensor in the monitoring unit collect the weld joint image and vibration signal, respectively. The laser welding unit performs actual welding on the aluminum plate according to the adjusted laser welding temperature, the target area of ​​the weld joint, and the laser emission power. After welding, the cooling unit cools the welded aluminum plate to obtain the finished welded aluminum plate.

[0072] Specifically, the control unit is connected to the vision sensor 2 to acquire the weld joint image, and to segment the weld joint outline and molten pool edge of the aluminum plate respectively, and to calculate the area of ​​the weld joint based on the segmented weld joint outline, and to identify burrs based on the segmented molten pool edge.

[0073] Specifically, threshold segmentation and edge detection algorithms are applied to the acquired images to separate the bright molten pool area from the base material background; the pixel area of ​​the segmented molten pool area in the image is calculated and converted to obtain the actual area of ​​the weld joint; the pixel area of ​​the molten pool area in the image at the beginning and end of the test segment is recorded; local protrusions of the molten pool edge contour are identified, and the curvature of the local protrusion is significantly greater than that of the smooth weld contour; if the local protrusion is greater than or equal to 0.1 mm equivalent pixel height, it is counted as a burr, and the total number of burrs appearing in the test segment image sequence is counted.

[0074] Specifically, the control unit is connected to the vision sensor 2 and the laser welding unit respectively to obtain the area of ​​the weld joint and calculate the change in the area of ​​the weld joint. If the change in area is greater than or equal to a preset second change, the laser welding temperature is reduced.

[0075] Specifically, given that the 6061 aluminum alloy plate has dimensions of 1500mm × 800mm × 2mm, and the vision sensor 2 is paired with a narrowband filter with a wavelength of 808±5nm, the general range of the preset first variation is [0.04mm]. 2 0.06mm 2 In a preferred embodiment, the preset first change amount is 0.05 mm. 2 The preset range for the second variation is generally [0.12mm]. 2 0.18mm 2 The preferred embodiment of the preset second variation amount is 0.15mm. 2 .

[0076] Those skilled in the art will understand that the selectable range of the preset first variation amount and the preset second variation amount provided in this embodiment, as well as the preferred embodiment, are the values ​​that best achieve the technical problem solved by the technical solution of the present invention under the conditions that the size of the 6061 aluminum alloy plate is 1500mm×800mm×2mm and the vision sensor 2 is equipped with a narrowband filter with a wavelength of 808±5nm. In actual applications or experiments, those skilled in the art can make adaptive adjustments to the preset first variation amount and the preset second variation amount according to the actual application environment and application scenario.

[0077] Specifically, the area change is the absolute value of the difference between the area of ​​the weld joint in the weld joint image collected at the end of the unit monitoring time and the area of ​​the weld joint at the beginning of the unit monitoring time.

[0078] Specifically, the laser welding temperature is adjusted by regulating the welding speed of the laser.

[0079] During implementation, if the difference between the area change and the preset second change exceeds 0.01 mm... 2 If this happens, the laser welding temperature will decrease by 0.5℃. For example, when the area change reaches 0.16mm... 2 At that time, compared to the preset second change amount of 0.15mm 2 Exceeded by 0.01mm 2 At this point, the laser welding temperature should be reduced by 0.5℃; if the area change reaches 0.17mm... 2 If it exceeds 0.02mm 2 The laser welding temperature will decrease by 1℃ accordingly.

[0080] In practice, the workstation of the present invention acquires images of the weld joint by setting a vision sensor 2, and the control unit segments and extracts features from the weld joint outline and the edge of the molten pool in the image, accurately calculates the area of ​​the weld joint and its change, and when the change in the area of ​​the weld joint within a unit monitoring time is greater than or equal to a preset second change, it is determined that the weld joint is in a state of significant expansion. The control unit automatically lowers the laser welding temperature to reduce the input heat energy, suppress excessive melting and lateral flow of metal, and prevent the molten pool from spreading and forming irregular boundaries.

[0081] Specifically, the control unit is connected to the vision sensor 2 to obtain the number of burrs in the molten pool under the condition that the area change is greater than or equal to a preset first change and less than a preset second change. If the number of burrs is greater than or equal to a preset number, the area of ​​the weld joint is increased as a correction area.

[0082] Specifically, under the condition that the laser welding unit performs a short-distance welding of 20mm at a power of 2kW and a welding speed of 3m / min at 10mm in front of the formal weld start end of the plate to be welded before the actual welding begins, the general range of the preset quantity is [5, 10], and the preferred embodiment of the preset quantity is 8.

[0083] Those skilled in the art will understand that the range of preset quantities and preferred embodiments provided in this embodiment are the values ​​that best address the technical problem of the present invention, selected under the condition that the laser welding unit performs a short-distance welding of 20mm at 10mm in front of the formal weld start end of the plate to be welded before the actual welding begins, with a power of 2kW and a welding speed of 3m / min. In actual applications or experiments, those skilled in the art can make adaptive adjustments to the preset quantities according to the actual application environment and application scenario.

[0084] In practice, if the difference between the number of burrs and the preset number exceeds one, the area of ​​the weld joint increases by 0.02 mm. 2 For example, if the number of burrs reaches 10, exceeding 2, the area of ​​the weld joint will increase by 0.04mm accordingly. 2 For example, the area of ​​the pre-set weld joint is 1.2 mm based on a 2mm plate thickness. 2 The corrected area is 1.2 mm. 2 +0.04mm 2 =1.24mm 2 .

[0085] In practice, the workstation described in this invention acquires information about the edge of the molten pool, identifies and counts the number of burrs. If the number of burrs exceeds a preset number, it is determined that the current edge disturbance of the molten pool is serious and there is a risk of local energy focusing or flow turbulence. By increasing the target area of ​​the weld joint as a correction value, a reasonable melting space is reserved to accommodate the possible overflow of metal fluid, thereby reducing the probability of burr generation and improving the stability of the molten pool.

[0086] Specifically, the control unit is connected to the vibration sensor and the laser welding unit respectively, and is used to obtain the vibration intensity of the aluminum plate under the condition that the area change is greater than or equal to a preset first change. If the vibration intensity is greater than or equal to the preset vibration intensity, the laser emission power is increased.

[0087] Specifically, given a 6061 aluminum alloy plate with dimensions of 1500mm × 800mm × 2mm and an output laser wavelength of 1070nm, the typical range for the preset vibration intensity is [0.4m / s²]. 2 0.8m / s 2The preferred embodiment for the preset vibration intensity is 0.5 m / s. 2 .

[0088] Those skilled in the art will understand that the range of preset vibration intensity provided in this embodiment and the preferred embodiment are the values ​​that best address the technical problem solved by the present invention under the conditions that the size of the 6061 aluminum alloy plate is 1500mm×800mm×2mm and the output laser wavelength is 1070nm. In actual applications or experiments, those skilled in the art can make adaptive adjustments to the preset vibration intensity according to the actual application environment and application scenario.

[0089] During implementation, if the difference between the vibration intensity and the preset vibration intensity exceeds 0.1 m / s², 2 Then the laser emission power increases by 50W, for example, when the vibration intensity reaches 0.6m / s². 2 At that time, the laser emission power should be increased by 50W.

[0090] Specifically, the laser welding unit includes:

[0091] Laser emitter 5, which is connected to the base 4, is used to emit laser light to the weld joint of the aluminum plate;

[0092] Robotic arm 1, which is connected to the laser emitter 5, is used to adjust the position of the laser emitter 5.

[0093] Specifically, the laser emitter 5 is a fiber laser with a rated power of 6 kilowatts and an output wavelength of 1070 mm. The laser beam is transmitted through a transmission fiber to the welding head at the end of the robotic arm 1, which is located above the position moving unit. The welding head is equipped with a focusing lens.

[0094] In practice, the workstation described in this invention monitors the structural vibration intensity of the aluminum sheet in real time during the welding process using vibration sensors. Due to the high thermal conductivity and large coefficient of thermal expansion of aluminum, transient thermal stress can easily induce overall or local vibration of the sheet during laser scanning, affecting the relative positioning accuracy between the laser beam and the weld, and even causing problems such as molten pool oscillation and porosity inclusions. By increasing the laser emission power, the single-point action time is shortened, the melting and solidification speed is accelerated, and the window period for the impact of base vibration on molten pool formation is reduced. At the same time, the high-power short pulse mode helps to improve energy density, enhance penetration ability, and counteract the energy dispersion effect caused by vibration, thereby improving the stability of welding.

[0095] This invention provides a control method for a modular collinear laser welding workstation, comprising:

[0096] Move the aluminum sheet to be welded to the welding position;

[0097] Preheat the aluminum sheet to be welded;

[0098] Welding tests were conducted on aluminum sheets using laser emission to form a molten pool on the sheets.

[0099] The area of ​​the weld joint and the burrs in the molten pool of the aluminum sheet were inspected separately.

[0100] The vibration intensity of the aluminum plate is determined based on the change in the area of ​​the weld joint, and the laser welding temperature is adjusted accordingly, or the target area of ​​the weld joint is corrected based on the number of burrs.

[0101] The laser emission power is adjusted according to the vibration intensity of the aluminum plate;

[0102] According to the laser welding temperature or the target area of ​​the weld joint, the aluminum sheet is actually welded according to the laser emission power to obtain the welded aluminum sheet.

[0103] The welded aluminum sheet is cooled to obtain the finished welded aluminum sheet.

[0104] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A modular collinear laser welding workstation, characterized in that, include: Base; A position moving unit, which is connected to the base, is used to carry and move the aluminum sheet to be welded; A laser welding unit is disposed above the position moving unit and is used to emit a laser to the weld joint of the aluminum sheet to form a molten pool. A monitoring unit, which is connected to the position moving unit, is used to monitor the area of ​​the weld joint, the number of burrs in the molten pool, and the vibration intensity of the aluminum plate. The control unit is connected to the position moving unit, the laser welding unit and the monitoring unit respectively, and is used to control the position moving unit and the laser welding unit to perform welding tests, and adjust the laser welding temperature of the laser welding unit according to the change in the area of ​​the weld joint in the welding test, or correct the target area of ​​the weld joint according to the number of burrs in the molten pool, and adjust the laser emission power according to the vibration intensity of the aluminum plate. The control unit is connected to a vision sensor to acquire the weld joint image, and to segment the weld joint outline and molten pool edge of the aluminum plate respectively, and to calculate the area of ​​the weld joint based on the segmented weld joint outline, and to identify burrs based on the segmented molten pool edge. The control unit is connected to the vibration sensor and the laser welding unit respectively, and is used to obtain the vibration intensity of the aluminum plate under the condition that the area change is greater than or equal to a preset first change. If the vibration intensity is greater than or equal to the preset vibration intensity, the laser emission power is increased.

2. The modular collinear laser welding workstation according to claim 1, characterized in that, Also includes: A preheating unit, which is connected to the position moving unit, is used to preheat the area of ​​the aluminum sheet to be welded. A cooling unit, connected to the laser welding unit, is used to cool the welded areas of the aluminum sheet.

3. The modular collinear laser welding workstation according to claim 2, characterized in that, The monitoring unit includes: A vision sensor, positioned above the base, acquires images of the weld joint to obtain the area of ​​the weld joint and the number of burrs in the molten pool. A vibration sensor, positioned below the vision sensor, is used to detect the vibration intensity of the aluminum sheet.

4. The modular collinear laser welding workstation according to claim 3, characterized in that, The control unit is connected to the vision sensor and the laser welding unit respectively to obtain the area of ​​the weld joint and calculate the change in the area of ​​the weld joint. If the change in area is greater than or equal to a preset second change, the laser welding temperature is reduced.

5. The modular collinear laser welding workstation according to claim 4, characterized in that, The area change is the absolute value of the difference between the area of ​​the weld joint in the weld joint image collected at the end of the unit monitoring time and the area of ​​the weld joint at the beginning of the unit monitoring time.

6. The modular collinear laser welding workstation according to claim 5, characterized in that, The control unit is connected to the vision sensor to obtain the number of burrs in the molten pool under the condition that the area change is greater than or equal to a preset first change and less than a preset second change. If the number of burrs is greater than or equal to a preset number, the area of ​​the weld joint is increased as a correction area.

7. The modular collinear laser welding workstation according to claim 6, characterized in that, The laser welding unit includes: A laser emitter, connected to the base, is used to emit a laser at the weld joint of the aluminum sheet; A robotic arm, connected to the laser emitter, is used to adjust the position of the laser emitter.

8. A control method for a modular collinear laser welding workstation as described in any one of claims 1-7, characterized in that, include: Move the aluminum sheet to be welded to the welding position; Preheat the aluminum sheet to be welded; Welding tests were conducted on aluminum sheets using laser emission to form a molten pool on the sheets. The area of ​​the weld joint and the burrs in the molten pool of the aluminum sheet were inspected separately. The vibration intensity of the aluminum plate is determined based on the change in the area of ​​the weld joint, and the laser welding temperature is adjusted accordingly, or the target area of ​​the weld joint is corrected based on the number of burrs. The laser emission power is adjusted according to the vibration intensity of the aluminum plate; According to the laser welding temperature or the target area of ​​the weld joint, the aluminum sheet is actually welded according to the laser emission power to obtain the welded aluminum sheet. The welded aluminum sheet is cooled to obtain the finished welded aluminum sheet.

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