A laser roll welding device suitable for complex curved plastic

Abstract

The application discloses a laser roll welding device suitable for complex curved plastic, which comprises a tool clamp installed on a workbench, a laser roll welding assembly acting on the tool clamp, and a mechanical hand assembly for driving the laser roll welding assembly to press the plastic workpiece on the tool clamp. The laser roll welding assembly is installed at the end of the mechanical hand assembly. The tool clamp comprises a positioning seat installed on the workbench, a plurality of clamping elements arranged around the positioning seat, and a pressing block installed on the top of each clamping element. A profiling surface is arranged on the positioning seat and is in close contact with the curved surface of the plastic workpiece. The pressing block is driven by the corresponding clamping element to rotate upward or downward, so as to alternately press the plastic workpiece on the tool clamp during welding. The application has the advantages of high welding precision, high welding strength, good uniformity, stable and adjustable pressing force, etc.

Description

Technical Field

[0001] This invention relates to the field of laser welding, and more particularly to a laser roll welding apparatus adapted to complex curved plastic surfaces. Background Technology

[0002] With the progress of the times and social development, the demand for product diversification and personalization is increasing, leading to a greater use of complex curved plastic products, especially in the automotive, home appliance, and medical industries. Traditional plastic products are mostly manufactured using injection molding. However, for complex curved plastic products, due to issues such as mold design and demolding, it is difficult to achieve the ideal complex surface in a single injection molding process. Therefore, the demand for secondary welding of complex curved surfaces is growing. Secondary welding methods for plastic products include ultrasonic welding, hot melt welding, friction welding, and laser welding. Due to its advantages such as high welding efficiency, high weld strength, aesthetically pleasing welds, no welding stress, and support for complex trajectory welding, laser welding has gradually become the mainstream welding method for plastics. However, because plastic products experience shrinkage and deformation during injection molding, it is difficult for two plastic parts to fit together well, resulting in a certain gap. In laser welding, once a gap appears, problems such as incomplete welds or low weld strength are prone to occur, reducing weld quality, especially in the welding of complex curved plastic surfaces, which urgently needs to be addressed.

[0003] To address the challenge of poor welding quality caused by gaps in the fit, many scholars and engineers have conducted extensive research. For example, Chinese patent CN106271083B discloses a method and apparatus for welding tabs on a soft-pack battery. This method involves pressing the tabs firmly onto the busbar using a rolling press, achieving immediate welding, and then using a laser to weld the tabs to the busbar. This patent employs a double-roller design, with a certain distance between the rollers and the laser head along the rolling direction. The rollers and laser head move synchronously, improving the efficiency of battery tab welding.

[0004] Chinese patent CN103737180B discloses a laser lap filler wire welding equipment for car roofs. It uses an adaptive roller unit to press the car roof. The adaptive roller unit is located on the side of the welding head and maintains a certain distance from the welding head. It moves synchronously with the welding head, which improves the weld strength and welding accuracy.

[0005] Chinese patent CN113751903B discloses a laser roll forming and welding device that uses three rollers to press the workpiece together. These three rollers are arranged on the same plane and are designated as a pre-tightening roller, a front clamping roller, and a rear clamping roller. This device achieves pressing during welding, reducing the overall process time and thus solving the problem of low production efficiency in laser welding fixtures.

[0006] However, if the rolling welding method disclosed in the above patent is applied to the welding of complex curved plastic surfaces, the following problems will exist: (1) The contact between the roller and the workpiece is a line contact, and its movement is unidirectional or reciprocating, which cannot adapt to the welding of complex curved surfaces; (2) During the welding closed trajectory process, the roller position remains the same, resulting in the weld seam on the product having both inner and outer seams, and the weld seam uniformity is poor; (3) If only the roller is used to press the workpiece during the welding process, the plastic in the unpressed part will warp and deform, resulting in high welding stress or the inability to weld.

[0007] Therefore, it is necessary to invent a new laser roll welding device adapted to complex curved plastic surfaces. Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of existing technologies by providing a laser roll welding device that features low welding stress, good weld uniformity, better bonding efficiency, and is more suitable for welding complex curved surfaces.

[0009] The laser roll welding apparatus for complex curved plastic surfaces provided by this invention includes a fixture mounted on a worktable, a laser roll welding assembly acting on the fixture, and a robotic arm assembly for driving the laser roll welding assembly to clamp the plastic workpiece on the fixture. The laser roll welding assembly is mounted at the end of the robotic arm assembly. The fixture includes a positioning seat mounted on the worktable, multiple clamping elements placed around the positioning seat, and pressure blocks mounted on top of each clamping element. The positioning seat has a contoured surface that conforms to the curved surface of the plastic workpiece. The pressure blocks are driven by the corresponding clamping elements to rotate upwards or downwards for clamping during welding. The plastic workpieces on the tooling fixture are alternately pressed; the robotic arm assembly includes a multi-joint robotic arm mounted on the worktable and a connecting plate rotatably mounted at the end of the multi-joint robotic arm; the laser roll welding assembly includes a housing, a laser mechanism and a roller mechanism. The housing is fixed to the bottom of the connecting plate. The laser mechanism includes a laser output head, a collimating lens and a focusing lens installed inside the housing and arranged sequentially along the optical path. The roller mechanism includes an inner cylinder fitted between the laser mechanism and the housing and rotatably engaged with the housing, rollers connected to the bottom of the inner cylinder and extending out of the housing, and a rotary motor mounted on the housing and connected to the inner cylinder. The inner cylinder and rollers are driven by the rotary motor to rotate around the axis of the housing.

[0010] To better complete the entire trajectory of welding complex curved surface contours, the number of joints in the multi-joint robotic arm is no less than 4.

[0011] The multi-joint robotic arm includes a base fixed to a workbench and an arm chain rotatably mounted on the base. The arm chain is formed by multiple robotic arms being hinged together in sequence. A connecting plate is rotatably mounted at the end of the arm chain. A vertical motor is provided between the base and the arm chain to drive the arm chain to rotate and adjust the arm chain's orientation angle. A horizontal motor is provided between each adjacent robotic arm of the arm chain to drive the corresponding robotic arm to rotate and adjust the arm chain's pitch angle. A drive motor is provided at the end of the arm chain to drive the connecting plate to rotate and adjust the connecting plate's orientation angle.

[0012] The arm chain is composed of a support arm, a large arm, and a small arm, which are hinged together in sequence. The support arm is rotatably mounted on the base and is connected to the output end of a vertical motor and driven by it to rotate around the vertical axis of the base to adjust the orientation angle of the support arm. The large arm and the small arm are respectively connected to the output end of a horizontal motor and are driven by it to rotate around the axis to adjust the included angle between adjacent arms. The connecting plate is rotatably mounted on the end of the small arm and connected to the output end of the drive motor.

[0013] A fixed plate is fixed to the bottom of the inner cylinder. Multiple positioning rods are evenly fixed to the bottom of the fixed plate. A compression spring is fitted on each positioning rod. A movable plate is movably fitted on the positioning rod below the compression spring. A limit nut is screwed onto the positioning rod below the movable plate. A roller connecting rod is fixed to the bottom of the movable plate by screws. The roller is rotatably mounted on the bottom of the roller connecting rod. The compression spring is compressed and drives the roller to contact the surface of the plastic workpiece.

[0014] The rotary motor is vertically mounted on one side of the housing. A bevel gear is mounted on the output shaft of the rotary motor. A bevel tooth part that meshes with the bevel gear is provided on the top of the inner cylinder. The horizontal rotation of the rotary motor is converted into the vertical rotation of the roller mechanism through the cooperation between the bevel gear and the bevel tooth part.

[0015] For ease of processing, the positioning seat is formed by fixing the upper and lower parts together, and the contour surface is located on the upper top surface.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. By adopting a combination of follow-up clamping and alternating clamping, the rollers are effectively in contact with the plastic workpiece during the welding process, and the entire workpiece is under clamping. This can significantly reduce the welding stress of the entire weld line and effectively solve the problems of incomplete welding, high welding stress, and long welding time caused by the gap in the fit of complex curved plastic workpieces.

[0018] 2. Only one roller is used, and the contact between the roller and the workpiece is point contact. The roller mechanism can rotate around the housing axis during the welding process. As the robot arm component moves, the roller can always be on the same side (inner or outer) of the weld, thus satisfying the welding of complex curved surfaces and ensuring the uniformity of the weld.

[0019] This invention has the advantages of high welding precision, high welding strength, good uniformity, and stable and adjustable clamping force. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention.

[0021] Figure 2 This is a schematic diagram of the isometric structure of the tooling fixture in this invention.

[0022] Figure 3 This is a schematic diagram of the axonal structure of the robotic arm assembly in this invention.

[0023] Figure 4 This is a partial cross-sectional view of the laser roll welding assembly in this invention.

[0024] The markings shown in the diagram and their corresponding component names are as follows:

[0025] 1. Workbench;

[0026] 2. Tooling fixtures; 21. Positioning seat; 22. Clamping elements; 23. Pressure block; 211. Contour surface;

[0027] 3. Robotic arm components; 31. Multi-joint robotic arm; 32. Connecting plate; 311. Base; 312. Support arm; 313. Upper arm; 314. Lower arm; 315. Vertical motor; 316. Horizontal motor; 317. Drive motor;

[0028] 4. Laser roll welding assembly; 41. Housing; 42. Laser output head; 43. Collimating lens; 44. Focusing lens; 45. Inner cylinder; 46. Fixing plate; 47. Positioning rod; 48. Compression spring; 49. Movable plate; 410. Limit nut; 411. Roller connecting rod; 412. Roller; 413. Rotary motor; 414. Bevel gear. Detailed Implementation

[0029] from Figure 1 As can be seen, the laser roll welding device adapted to complex curved plastic surfaces of the present invention includes a worktable 1, a tooling fixture 2, a robot arm assembly 3, and a laser roll welding assembly 4. The tooling fixture 2 is installed in front of the worktable 1 for clamping the plastic workpiece; the robot arm assembly 3 is installed in the middle and rear of the worktable 1 for driving the laser roll welding assembly 4 to press the plastic workpiece on the tooling fixture; the laser roll welding assembly 4 is installed at the end of the robot arm assembly 3 for performing laser roll welding on the plastic workpiece on the tooling fixture.

[0030] In this invention, the workbench 1 is used to support the tooling fixture 2, the robot arm assembly 3, and the laser roll welding assembly 4, and should have good rigidity, strength, and stability.

[0031] In this invention, the robot arm assembly 3 will experience changes in center of gravity and swaying during the welding process. The stress distribution of the worktable 1 should be checked according to the weight of the robot arm assembly 3 and the changes in center of gravity during its movement, so that the safety factor is not less than 1.5.

[0032] In this invention, in order to ensure that the shape error of the welded workpiece is within a certain range, the flatness of the workbench 1 surface is no more than 0.2mm; considering the difficulty of handling and moving large devices, casters or feet are installed at the bottom of the workbench 1 to ensure that the workbench 1 surface is level and movable.

[0033] from Figure 2 As can be seen, the tooling fixture 2 in this invention includes a positioning seat 21, multiple clamping elements 22, and multiple pressure blocks 23. The positioning seat 21 is detachably mounted at the front position of the worktable 1 by screws. A contoured surface 211 that conforms to the curved surface of the plastic workpiece is provided on the surface of the positioning seat 21. The clamping elements 22 are detachably fixed to the worktable 1 at the periphery of the positioning seat 21 by screws. The pressure blocks 23 are mounted one-to-one on the top of each clamping element 22. The pressure blocks 23 are driven by the corresponding clamping elements 22 to rotate upward or downward. During welding, the pressure blocks 23 rotate downward to clamp the plastic workpiece on the positioning seat 21, and rotate upward to release the plastic workpiece on the positioning seat 21, thus completing the alternating clamping of the plastic workpiece on the tooling fixture 2.

[0034] In this invention, the tooling fixture 2 serves to fix and install the plastic workpiece. The positioning seat 21 is made according to the curved plastic workpiece and has a suitable positioning reference, so that the curved plastic workpiece is accurately installed on the positioning seat 21. The contoured surface 211 on the positioning seat 21 effectively fits the curved surface of the plastic workpiece, ensuring that the curved surface of the plastic workpiece does not deform during the roll welding process. There are four clamping elements 22, which are located on the four sides of the positioning seat 21. Each clamping element 22 can effectively clamp the plastic workpiece through the pressure block 23, ensuring that the position of the plastic workpiece does not move during the roll welding process.

[0035] In this invention, in order to quickly clamp the laser roll welding assembly when it leaves and quickly release it when it approaches, the clamping element is a rotary cylinder, and the control method is pneumatic control and electromagnetic control.

[0036] In this invention, the positioning seat 21 is formed by fixing the upper and lower parts together, and the contour surface 211 is provided on the upper top surface.

[0037] from Figure 3As can be seen, the robotic arm assembly 3 in this invention includes a multi-joint robotic arm 31 with no less than 4 joints and a connecting plate 32 rotatably mounted at the end of the multi-joint robotic arm 31. The multi-joint robotic arm 31 is detachably mounted at the rear of the worktable 1 via a threaded connector.

[0038] from Figure 3 As can be seen, in this invention, the multi-joint robotic arm 31 includes a base 311, a support arm 312, a large arm 313, a small arm 314, a vertical motor 315, a horizontal motor 316, and a drive motor 317. The base 311 is detachably mounted at the rear of the workbench 1 via a threaded connector. The vertical motor 315 is detachably mounted vertically on the base 311 via a threaded connector. The support arm 312, the large arm 313, and the small arm 314 are sequentially hinged to form an arm chain. The support arm 312 at the front end of the arm chain is connected to the output shaft of the vertical motor 315. The output shaft of the vertical motor 315 drives the drive arm chain to rotate around the vertical axis of the base 31 to adjust the orientation angle of the arm chain. There are two horizontal motors 316, which are respectively fixed on the support arm 312 at the connection with the large arm 313 and on the large arm 313 at the connection with the small arm 314, located on the support arm. The output end of the horizontal motor 316 at position 312 is connected to the front end of the upper arm 313. The output end of the horizontal motor 316 at the upper arm 313 is connected to the front end of the forearm 314. The upper arm 313 is driven by the corresponding horizontal motor 316 to rotate around its output axis to adjust the angle between the support arm 312 and the upper arm 313. The forearm 314 is driven by the corresponding horizontal motor 316 to rotate around its output axis to adjust the angle between the upper arm 313 and the forearm 314. The arm chain is controlled by two horizontal motors 316 to adjust the pitch angle. The drive motor 317 is detachably and vertically mounted at the end of the forearm 314 through a threaded connector. The connecting plate 32 is fixed on the output shaft of the drive motor 317. The rotation of the output shaft of the drive motor 317 drives the connecting plate 32 to rotate around its axis at the end of the arm chain to adjust the orientation angle of the connecting plate 32.

[0039] In this invention, the specific number of joints of the multi-joint robotic arm 31 is determined according to the complexity of the welding surface of the plastic workpiece.

[0040] from Figure 4 As can be seen, the laser roll welding assembly 4 in this invention includes a housing 41, a laser mechanism, and a roller mechanism. The housing 41 is detachably fixed to the bottom of the connecting plate 32 by a threaded connector. The laser mechanism includes a laser, a laser output head 42, a collimating lens 43, and a focusing lens 44. The laser output head 42, the collimating lens 43, and the focusing lens 44 are arranged sequentially in the housing 41 along the optical path. The input end of the laser output head 42 is electrically connected to the laser through an optical fiber.

[0041] The roller mechanism includes an inner cylinder 45, a fixed plate 46, positioning rods 47, compression springs 48, a movable plate 49, a limit nut 410, roller connecting rods 411, rollers 412, and a rotary motor 413. The inner cylinder 45 is fitted between the laser mechanism and the housing 41. The inner cylinder 45 is rotatably secured within the housing 41 via bearings. The fixed plate 46 is fixed to the bottom of the inner cylinder 44. Multiple positioning rods 47 are evenly fixed to the bottom of the fixed plate 46. The movable plate 49 is movably fitted onto the positioning rods 47. Compression springs 48 are fitted one-to-one onto the positioning rods 47 between the fixed plate 46 and the movable plate 49. The limit nuts 410 are threaded one-to-one onto the movable plate. On the positioning rod 47 below 49, the roller connecting rod 411 is detachably fixed to the bottom of the movable plate 49 by screws and extends out of the housing 41. The roller 412 is rotatably mounted on the bottom of the roller connecting rod 411. The axis of the roller 412 is arranged perpendicular to the laser beam path. The rotary motor 413 is mounted on the housing 41 and its output shaft is connected to the inner cylinder 45. The compression spring is compressed to apply stable pressure to the roller 412, driving it to contact the surface of the plastic workpiece. The inner cylinder 45 and the roller 412 are driven by the rotary motor 413 to rotate around the axis of the housing 41, so that the roller 412 is always on the same side (inner or outer) of the weld during the welding process.

[0042] from Figure 4 It can also be seen that in this invention, the rotary motor 413 is vertically mounted on one side of the housing 41, a bevel gear 414 is mounted on the output shaft of the rotary motor 413, and a bevel tooth portion that meshes with the bevel gear 414 is provided on the top of the inner cylinder 45. The horizontal rotation of the rotary motor 413 is converted into the vertical rotation of the roller mechanism through the cooperation of the bevel gear 414 and the bevel tooth portion.

[0043] In this invention, the rotary motor 413 is a small stepper motor or servo motor with a rotation accuracy of not less than 0.5°; the bevel gear 414 and the bevel tooth part have good strength, rigidity and structural compactness.

[0044] In this invention, a laser with appropriate wavelength, power and output mode is selected according to the material type, composition, transmittance and thickness parameters of the plastic workpiece; the optical fiber should have good flexibility and be able to reliably connect the laser and the laser output head 42.

[0045] In this invention, collimating lens 43 and focusing lens 44 are selected according to the laser wavelength and divergence angle. The divergent light output by the laser output head 42 is converted into parallel light by collimating lens 43, and then converted into a focused state by focusing lens 44. The laser beam that shines on the plastic workpiece is a laser beam with good direction and concentrated energy.

[0046] In this invention, the roller is made of polyurethane or other plastics to avoid scratching the surface of the plastic workpiece during rolling. Its diameter is preferably between 5-10 mm, and it can withstand a pressure of no less than 100 N. The roller connecting rod connects the roller to the housing. It should be installed away from the laser beam and should have high strength and rigidity, preferably made of high-strength steel to ensure that the deformation during roll forming and welding does not exceed 1 mm. The springs mainly serve to adjust the roller pressure; the number of springs should not be less than three to ensure consistent roller pressure.

[0047] The working principle of this invention for accompanying and alternating clamping is as follows:

[0048] 1. The following clamping is completed by the robotic arm assembly 3 and the laser roll welding assembly 4. During the roll welding process, the roller 412 contacts the plastic workpiece. When the laser beam welds the plastic workpiece, the roller 412 applies a clamping force to the surface of the plastic workpiece, making the welding position on the curved surface of the plastic workpiece more accurate. When the laser beam moves to weld, the roller 412 also moves along with it, and the distance between the laser beam and the roller 412 remains unchanged.

[0049] 2. Alternating clamping is achieved through the clamping elements 22 of the tooling fixture 2. Because the structure of plastic workpieces is usually quite compact, the distance between the weld seam and the workpiece edge is small. When clamping the workpiece, the clamping elements 22 often obstruct the weld seam, preventing welding. Therefore, by controlling the welding position, when the roller 412 and laser beam approach a clamping element 22, that clamping element 22 is closed, causing the corresponding pressure block 23 to rotate upwards into a non-working state, releasing the plastic workpiece and no longer obstructing the weld seam. When the roller 412 and laser beam complete the welding at that point, the clamping element 22 is activated, causing the corresponding pressure block 23 to rotate downwards into a working state, clamping the plastic workpiece again, thus achieving alternating clamping. During the entire roll welding process, each clamping element 22 will be opened and closed once.

[0050] The process of using this invention is as follows:

[0051] 1. When welding, place the plastic workpiece on the positioning seat 21, turn on the power, and the clamping element 22 connected to the tooling fixture drives the pressure block 23 to press the workpiece, ensuring that the position of the plastic workpiece does not move during the roll welding process.

[0052] 2. Start the vertical motor 315, and the robotic arm assembly 3 connected to the vertical motor 315 will rotate on the worktable 1. Start the horizontal motor 316, and drive the joints of the multi-joint robotic arm 31 to rotate through the rotation of the horizontal motor 316, so as to ensure that the roller 412 is in constant contact with the plastic workpiece during the roll welding process.

[0053] 3. Start the laser, the laser roll welding assembly 4 emits a laser, and the light output by the laser output head 42 is calibrated by the collimating lens 31 and focused by the focusing lens 32, and then directed to the front of the roller 412 for heating.

[0054] 4. When the laser beam welds the plastic workpiece, the compression spring 48 applies stable pressure to the roller 412. The roller 412 then applies a clamping force to the surface of the plastic workpiece. The housing 41 moves with the curved shape of the plastic workpiece, and the rotary motor 412 is started. The horizontal rotation of the rotary motor 412 is converted into the vertical rotation of the roller mechanism, so that the roller is always on the same side of the weld. The laser beam moves to weld, and the roller 412 moves with it. The distance between the laser beam and the roller 412 remains unchanged.

[0055] 5. When the roller 412 and the laser beam approach a clamping element 22, the clamping element 22 is released and no longer obstructs the weld position; when the roller 412 and the laser beam complete the welding of the weld at that location, the clamping element 22 clamps again.

[0056] Throughout the welding process, the curved surface is welded by the roller 412 moving with the laser beam and the clamping element 22 alternately pressing.

Claims

1. A laser roll welding apparatus adapted to complex curved plastic surfaces, comprising a tooling fixture (2) mounted on a worktable (1) and a laser roll welding assembly (4) acting on the tooling fixture, characterized in that: It also includes a robotic arm assembly (3) for driving the laser roll welding assembly to perform follow-up clamping on the plastic workpiece on the tooling fixture, the laser roll welding assembly being installed at the end of the robotic arm assembly. The tooling fixture includes a positioning seat (21) mounted on the workbench, multiple clamping elements (22) placed around the positioning seat, and pressure blocks (23) mounted on the top of each clamping element. The positioning seat is provided with a contoured surface (211) that fits against the curved surface of the plastic workpiece. The pressure blocks are driven by the corresponding clamping elements to rotate upward or downward, and are used to alternately press the plastic workpiece on the tooling fixture during welding. The robotic arm assembly includes a multi-joint robotic arm (31) mounted on a workbench and a connecting plate (32) rotatably mounted at the end of the multi-joint robotic arm. The laser roll welding assembly includes a housing (41), a laser mechanism, and a roller mechanism. The housing is fixed to the bottom of the connecting plate. The laser mechanism includes a laser output head (42), a collimating lens (43), and a focusing lens (44) installed inside the housing and arranged sequentially along the optical path. The roller mechanism includes an inner cylinder (45) fitted between the laser mechanism and the housing and rotatedly engaged with the housing, a roller (412) connected to the bottom of the inner cylinder and extending out of the housing, and a rotary motor (413) installed on the housing and connected to the inner cylinder. The inner cylinder and the roller are driven by the rotary motor to rotate around the axis of the housing, so that the roller is always on the same side of the weld. A fixed plate (46) is fixedly attached to the bottom of the inner cylinder. Multiple positioning rods (47) are evenly fixedly attached to the bottom of the fixed plate. A compression spring (48) is fitted on each positioning rod. A movable plate (49) is movably fitted on the positioning rod below the compression spring. A limit nut (410) is screwed onto the positioning rod below the movable plate. A roller connecting rod (411) is fixed to the bottom of the movable plate by screws. The roller is rotatably installed at the bottom of the roller connecting rod. The compression spring is compressed and drives the roller to contact the surface of the plastic workpiece. When the laser beam performs walking welding, the roller moves along with it and applies a clamping force to the surface of the plastic workpiece to achieve accompanying clamping. When the roller and laser beam approach a clamping element, the clamping element is closed, causing the corresponding pressure block to rotate upward and enter a non-working state, releasing the plastic workpiece and no longer obstructing the weld position; when the roller and laser beam complete the welding of the weld at that point, the clamping element is activated, causing the corresponding pressure block to rotate downward and enter a working state, clamping the plastic workpiece again, thus achieving alternating clamping. Throughout the welding process, the curved surface is welded by a combination of the accompanying pressure of the rollers and the alternating pressure of the clamping elements.

2. The laser roll forming welding device adapted to complex curved plastic surfaces according to claim 1, characterized in that: The number of joints in the multi-joint robotic arm is no less than 4.

3. The laser roll forming welding device adapted to complex curved plastic surfaces according to claim 2, characterized in that: The multi-joint robotic arm includes a base (311) fixed to the workbench and an arm chain rotatably mounted on the base. The arm chain is formed by multiple robotic arms being hinged together in sequence. A connecting plate is rotatably mounted at the end of the arm chain. A vertical motor (315) is provided between the base and the arm chain to drive the arm chain to rotate and adjust the arm chain's orientation angle. A horizontal motor (316) is provided between each adjacent robotic arm of the arm chain to drive the corresponding robotic arm to rotate and adjust the arm chain's pitch angle. A drive motor (317) is provided at the end of the arm chain to drive the connecting plate to rotate and adjust the connecting plate's orientation angle.

4. The laser roll forming welding device adapted to complex curved plastic surfaces according to claim 3, characterized in that: The arm chain is formed by hinged support arm (312), upper arm (313) and lower arm (314) in sequence. The support arm is rotatably mounted on the base and is connected to the output end of a vertical motor and driven by it to rotate around the vertical axis of the base to adjust the orientation angle of the support arm. The upper arm and lower arm are respectively connected to the output end of a horizontal motor and are driven by it to rotate around the axis to adjust the included angle between adjacent arms. The connecting plate is rotatably mounted on the end of the lower arm and connected to the output end of the drive motor.

5. The laser roll forming welding device adapted to complex curved plastic surfaces according to claim 1, characterized in that: The rotary motor is vertically mounted on one side of the housing. A bevel gear (414) is mounted on the output shaft of the rotary motor. A bevel tooth part that meshes with the bevel gear is provided at the top of the inner cylinder. The horizontal rotation of the rotary motor is converted into the vertical rotation of the roller mechanism through the cooperation between the bevel gear and the bevel tooth part.

6. The laser roll forming welding device adapted to complex curved plastic surfaces according to claim 1, characterized in that: The positioning seat is formed by two parts, upper and lower, and the contoured surface is located on the top surface of the upper part.

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