A special laser welding method and device for thick plate narrow gap structures based on coaxial mixing of wire powder

Abstract

This patent relates to a special laser welding method and device for thick plate narrow-gap structures based on coaxial mixing of wire and powder. The device includes components such as a motion mechanism, a powder feeder, a special laser head for wire-powder mixing welding, a control system, and a laser. The special laser head for wire-powder mixing welding includes a wire collimator, a CCD camera, a powder feeding port, a shielding gas channel, a focusing lens, a reflector, a collimating lens, and a fiber optic access module, etc., which can achieve precise coupling of wire materials, powder materials, and laser beams. In addition, the control system has a welding knowledge base, adjusts welding parameters according to the monitoring results, and realizes automatic coordinated adjustment of powder feeding speed and wire feeding speed. The device has multiple working modes, and has the functions of local repair and enhancement of weld defects. At the same time, it can adapt to different base materials and powder materials to achieve high-strength and high-quality narrow-gap structure welding.

Description

Technical Field

[0001] The present invention relates to the field of aluminum alloy welding, and particularly to a special laser welding method and device for thick plate narrow-gap structures based on coaxial mixing of wire and powder. Background Art

[0002] In recent years, the narrow-gap laser welding technology is considered as the key core technology for solving the welding of complex structures of medium and thick plates. It combines the advantages of narrow-gap welding and laser welding technologies, and can effectively improve the welding deformation and residual stress level of welded joints. Therefore, it shows great application potential in the field of medium and thick plate welding. Narrow-gap laser wire filling welding, by introducing a welding wire, on the one hand, can improve the adaptability of laser welding to the assembly accuracy of workpieces, thus making up for the disadvantages of single laser welding; on the other hand, the introduction of the welding wire can also supplement alloying elements to the weld seam and improve the comprehensive performance of the joint.

[0003] However, traditional narrow-gap laser wire filling welding uses a side-axis wire feeding method for welding, that is, the laser and wire feeding are two independent systems, and there is an axial difference in space. Although this mode reduces the design cost to a certain extent, it also introduces some problems: First, the non-coaxiality of the light and wire leads to poor welding stability, that is, tiny relative displacement fluctuations will directly affect the shape of the molten pool, thus affecting the welding quality; Second, the welding wire is only irradiated unidirectionally by the laser, resulting in uneven heating of the material, and high heat input will also cause the molten pool to remain at a high temperature and cool slowly; Finally, the fusion of the weld sidewall is affected by the groove size, and defects such as incomplete fusion of the weld sidewall, pores and root cracks are likely to occur if the welding process is not properly controlled.

[0004] To solve the above problems, this patent proposes a wire-powder coaxial laser welding method and designs a special laser welding device for narrow-gap structures. This method realizes the effective welding of narrow-gap structures through wire-powder mixed welding. At the same time, through the coordinated adjustment of the intelligent control system, the stability of the welding process and the weld quality are improved. This special laser welding device has important application value and technological innovation significance in the field of laser welding of thick plate narrow-gap structures. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the present invention provides a special laser welding method and device for thick plate narrow gap structures based on coaxial mixing of wire and powder. The device includes components such as a motion mechanism, a powder feeder, a special laser head for wire-powder mixing welding, a control system, and a laser. The special laser head for wire-powder mixing welding includes a wire collimator, a CCD camera, a powder feeding port, a shielding gas channel, a focusing lens, a reflecting mirror, a collimating lens, and a fiber optic access module, etc., which can achieve precise coupling of wire materials, powder materials, and laser beams. In addition, the control system has a welding knowledge base, adjusts welding parameters according to the monitoring results, and realizes automatic coordinated adjustment of powder feeding speed and wire feeding speed. The device has multiple working modes, and has the functions of local repair and enhancement of weld defects. At the same time, it can adapt to different base materials and powder materials to achieve high-strength and high-quality narrow gap structure welding.

[0006] To achieve the above object, the present invention is realized through the following technical solutions.

[0007] A special laser welding device for thick plate narrow gap structures based on coaxial mixing of wire and powder mainly includes a motion mechanism, a powder feeder, a special laser head for wire-powder mixing welding, a control system, and a laser;

[0008] Further, the control system is connected to the motion mechanism, the powder feeder, the special laser head for wire-powder mixing welding, and the laser, and is used to control the operation of each system and the selection of welding parameters, and at the same time, it can monitor the welding quality of the narrow gap structure in real time.

[0009] Further, the special laser head for wire-powder mixing welding includes a wire collimator, a CCD camera, a second reflecting mirror, a second collimating lens, a protective lens, a powder feeding port, a shielding gas channel, a focusing lens, a first reflecting mirror, a first collimating lens, and a fiber optic access module.

[0010] Further, the laser beam is the beam output by the laser through the fiber optic access module; the first collimating lens is connected to the fiber optic access module, and the diameter of the laser beam is enlarged after passing through the first collimating lens; the first reflecting mirror deflects the angle of the laser beam to the focusing lens; two focusing lenses with opposite directions change the laser beam into a hollow laser beam, that is, an annular laser beam; the second reflecting mirror converts the annular laser beam into a laser beam perpendicular to the direction of the plate, and the annular laser beam is focused on the position below the outlet of the conical nozzle through the second collimating lens.

[0011] Further, the wire collimator sequentially passes through the second reflecting mirror, the second collimating lens, and the protective lens, and the wire is conveyed to the welding position through the wire collimator; the powder feeding port is connected to the powder feeder and can convey the powder to the welding position; the CCD camera can monitor the surface state of the molten pool during the narrow gap structure laser welding in real time, so as to achieve precise coupling of the annular laser beam, the wire, and the powder; the special laser head for wire-powder mixing welding is provided with a shielding gas channel to realize coaxial shielding of the gas during the wire-powder mixing laser welding process of the thick plate narrow gap structure.

[0012] Furthermore, the control system includes an intelligent welding knowledge base, which can determine the optimal welding parameters based on the weld quality monitored by the CCD camera and the groove dimensions of the narrow-gap structure; meanwhile, the control system adjusts the powder feeding speed and wire feeding speed in real time to achieve the coordinated control and automatic start-stop of the two, ensuring the stability of the welding process and the quality of the weld.

[0013] Furthermore, the special laser head for powder-wire hybrid welding has multiple working modes, including coaxial welding of light-wire-powder, single laser welding, light-wire welding, and light-powder welding, and can independently select the welding mode based on the welding requirements; the special laser head for powder-wire hybrid welding also has the functions of local repair and enhancement of weld defects, can realize local repair of the defects occurring in the welding process, and can also achieve the reinforcement of the weld by adjusting the powder composition, improving the welding quality.

[0014] Furthermore, the CCD camera can monitor the phenomenon of lack of fusion on the side wall during the welding process in real time, and can adjust the spot diameter, defocus amount, laser power, powder feeding amount, and wire feeding speed in real time for this phenomenon; if it is detected that there is a lack of fusion on the side wall or the weld quality is poor in the previous weld when welding the next weld, powder can be pre-sprayed at the defect, and local laser repair can be carried out during the subsequent welding process to ensure the quality of the previous weld.

[0015] Furthermore, the CCD camera can monitor the change of the groove dimensions of the narrow-gap structure in real time, and independently select the welding parameters and welding method for the next weld based on the intelligent welding knowledge base system.

[0016] Furthermore, the intelligent welding knowledge base can automatically select the powder material and the composition and content of the welding wire suitable for the base material. The powder can be corrosion-resistant powder, high-temperature-resistant powder, etc., to achieve high-strength and high-quality welding of the narrow-gap structure.

[0017] Furthermore, the laser can be a continuous laser or a pulsed laser, and a suitable laser can be selected according to the actual application scenario to meet different welding requirements.

[0018] A narrow-gap structure powder-wire coaxial laser welding method realized by a powder-wire coaxial hybrid laser welding device can be achieved through the following steps:

[0019] Step 1, use the visual inspection method to inspect the welding part to be welded, and adjust the position of the special laser head for powder-wire hybrid welding with the help of a robot. Independently select the powder material and the welding wire composition through the intelligent welding knowledge base, and load the selected powder material and welding wire into the powder feeder and wire feeder.

[0020] Step 2: The control system controls the powder feeder, wire feeder, and laser to start. According to the optimal welding process and parameters obtained from the intelligent welding knowledge base, the welding of the narrow-gap structure begins.

[0021] Step 3: Based on the weld quality and orifice dimensions of the narrow-gap structure, welding parameters are selected based on the intelligent welding knowledge base system, and the welding parameters, powder feeding speed, and wire feeding speed are adjusted in real time to ensure the quality and stability of the weld.

[0022] Step 4: If, when performing the next weld, defects are detected in the weld in real time through the CCD camera, powder feeding repair operations can be carried out. By spraying powder at the defect location, the repair of the previous weld is achieved.

[0023] The advantages and positive effects of the present invention are as follows:

[0024] A special laser welding method and device for thick plate narrow-gap structures based on coaxial wire and powder mixing of the present invention have advantages such as improved narrow-gap welding quality, enhanced device adaptability, and increased welding efficiency. The device improves the welding quality of the narrow-gap structure through wire and powder mixing welding, reducing the deformation and residual stress of the welded joint. At the same time, the device has multiple working modes and supports local repair of weld defects, meeting different welding requirements and improving welding adaptability. The intelligent control system can adjust welding parameters according to the monitoring results, coordinately controlling the powder feeding speed and wire feeding speed to improve welding efficiency and stability. In summary, the special laser welding device for thick plate narrow-gap structures based on coaxial wire and powder mixing can solve defect problems such as lack of fusion on the side wall of the weld, porosity, and root cracks, and has broad application prospects. Description of the Drawings

[0025] Figure 1 It is a diagram of a special laser welding device for thick plate narrow-gap structures based on coaxial wire and powder mixing.

[0026] Figure 2 It is a process flow of a special laser welding method for thick plate narrow-gap structures based on coaxial wire and powder mixing.

[0027] Figure 3 It is a schematic diagram of laser powder feeding repair welding for lack of fusion defects.

[0028] 1 - Motion mechanism

[0029] 2 - Powder feeder

[0030] Laser head specialized for 3-wire and powder hybrid welding: 31 - welding wire; 32 - wire collimator; 33 - CCD camera; 34 - second reflector; 35 - second collimating lens; 36 - protective lens; 37 - powder feeding port; 38 - narrow gap structure; 39 - shielding gas channel; 40 - focusing lens; 41 - first reflector; 42 - first collimating lens; 43 - laser beam; 44 - fiber optic access module

[0031] 5 - Control system

[0032] 6 - Laser Specific implementation manners

[0033] For the convenience of those skilled in the art to understand, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the convenience of description, only the parts related to the present invention rather than all the structures are shown in the accompanying drawings.

[0034] The present invention will be further described below through a specific embodiment.

[0035] Embodiment

[0036] This example is based on the requirements of lightweight alloy thick - wall structural parts and their high - efficiency connection processes, and conducts narrow - gap wire - powder coaxial hybrid laser welding of 8 - mm - thick TC4 titanium alloy.

[0037] As Figure 1 shown, the present invention discloses a special laser welding device for thick - plate narrow - gap structures based on wire - powder coaxial hybrid, mainly including a motion mechanism 1, a powder feeder 2, a laser head 3 specialized for wire - powder hybrid welding, a control system 5, and a laser 6.

[0038] The laser head 3 specialized for wire - powder hybrid welding includes a wire collimator 32, a CCD camera 33, a second reflector 34, a second collimating lens 35, a protective lens 36, a powder feeding port 37, a shielding gas channel 39, a focusing lens 40, a first reflector 41, a first collimating lens 42, and a fiber optic access module 44; the laser beam 43 is the beam output by the laser through the fiber optic access module 44; the first collimating lens 42 is connected to the fiber optic access module 44, and the diameter of the laser beam 43 expands after passing through the first collimating lens 42; the first reflector 41 deflects the angle of the laser beam to the focusing lens; the two focusing lenses 37 with opposite directions change the laser beam into a hollow laser beam, that is, an annular laser beam; the second reflector 34 converts the annular laser beam into a laser beam perpendicular to the direction of the plate, and the annular laser beam is focused at a position below the outlet of the conical nozzle after passing through the second collimating lens 35.

[0039] The wire collimator sequentially passes through the second reflector 34, the second collimating lens 35, and the protective lens 36, and the welding wire 31 is conveyed to the welding part to be welded through the wire collimator 32; the powder feeding port 37 is connected to the powder feeder 2, and powder can be conveyed to the welding part to be welded; the CCD camera 33 can monitor the surface state of the molten pool in the narrow-gap structure laser welding in real time, so as to realize the precise coupling of the annular laser beam, the welding wire and the powder; the special laser head 3 for wire-powder hybrid welding is provided with a shielding gas channel 39 to realize the coaxial shielding of the gas in the wire-powder hybrid laser welding process of the thick plate narrow-gap structure; the control system 5 includes an intelligent welding knowledge base, which can determine the optimal welding parameters based on the weld quality monitored by the CCD camera 33 and the groove size of the narrow-gap structure; at the same time, the control system 5 adjusts the powder feeding speed and the wire feeding speed in real time to realize the coordinated control and automatic start and stop of the two, and ensure the stability of the welding process and the quality of the weld.

[0040] The special laser head for wire-powder hybrid welding has a variety of working modes, including coaxial welding of light-wire-powder, single laser welding, light-wire welding, and light-powder welding, and can independently select the welding mode based on the welding requirements; the special laser head for wire-powder hybrid welding also has the functions of local repair and enhancement of weld defects, can realize the local repair of defects occurring in the welding process, and can also realize the reinforcement of the weld by adjusting the powder composition to improve the welding quality.

[0041] The CCD camera can monitor the phenomenon of incomplete fusion of the side wall during the welding process in real time. For this phenomenon, the spot diameter, defocus amount, laser power, powder feeding amount, and wire feeding speed can be adjusted in real time; if it is monitored that there is incomplete fusion of the side wall or poor weld quality in the previous weld when welding the next weld, powder can be pre-sprayed at the defect, and local laser repair can be carried out during the subsequent welding process to ensure the quality of the previous weld.

[0042] The CCD camera can monitor the change of the groove size of the narrow-gap structure 38 in real time, and independently select the welding parameters and welding method for the next weld based on the intelligent welding knowledge base system.

[0043] The intelligent welding knowledge base can automatically select the powder material suitable for the base material and the composition and content of the welding wire. The powder composition can be corrosion-resistant powder, high-temperature-resistant powder, etc., to realize high-strength and high-quality welding of the narrow-gap structure.

[0044] The laser can be a continuous laser or a pulsed laser, and a suitable laser can be selected according to the actual application scenario to meet different welding requirements.

[0045] A narrow-gap structure wire-powder coaxial laser welding method realized by a special laser welding device for thick plate narrow-gap structure based on wire-powder coaxial mixing, the method includes the following steps:

[0046] Step 1: Detect the welding parts to be welded by visual inspection method, and adjust the position of the special laser head 3 for wire-powder hybrid welding with the help of the motion mechanism 1. Autonomously select the powder material and wire composition from the intelligent welding knowledge base, and load the selected powder material and wire into the powder feeder 2 and the wire feeder;

[0047] Step 2: The control system controls the powder feeder 2, the wire feeder and the laser 6 to start, and starts welding the narrow-gap structure according to the optimal welding process and parameters obtained from the intelligent welding knowledge base;

[0048] Step 3: Based on the weld quality and the skin opening size of the narrow-gap structure, select the welding parameters from the intelligent welding knowledge base system, and adjust the welding parameters, powder feeding speed and wire feeding speed in real time to ensure the quality and stability of the weld;

[0049] Step 4: If there are defects in the weld detected in real time by the CCD camera 33 when welding the next weld, the powder feeding repair operation can be carried out, and the previous weld can be repaired by spraying powder at the defect.

[0050] Obviously, the above embodiments of the present invention are only examples for clearly explaining the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. The content of this specification should not be construed as a limitation to the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A special laser welding device for thick plate narrow-gap structures based on coaxial mixing of wire and powder, characterized in that: it mainly includes a motion mechanism (1), a powder feeder (2), a special laser head for wire and powder mixing welding (3), a control system (5) and a laser (6); the control system (5) is connected to the motion mechanism (1), the powder feeder (2), the special laser head for wire and powder mixing welding (3) and the laser (6), and is used to control the operation of each system and the selection of welding parameters, and at the same time, it monitors the welding quality of the narrow-gap structure (38) in real time; the special laser head for wire and powder mixing welding (3) includes a wire collimator (32), a CCD camera (33), a second reflector (34), a second collimating lens (35), a protective lens (36), a powder feeding port (37), a protective gas channel (39), a focusing lens (40), a first reflector (41), a first collimating lens (42), and an optical fiber access module (44); the laser beam (43) is the beam output by the laser through the optical fiber access module (44); the first collimating lens (42) is connected to the optical fiber access module (44), and the diameter of the laser beam (43) expands after passing through the first collimating lens (42); the first reflector (41) deflects the angle of the laser beam to the focusing lens; two focusing lenses (40) with opposite directions change the laser beam into a hollow laser beam, that is, an annular laser beam; the second reflector (34) converts the annular laser beam into a laser beam perpendicular to the direction of the plate, and after passing through the second collimating lens (35), the annular laser beam is focused below the outlet position of the conical nozzle; the wire collimator sequentially passes through the second reflector (34), the second collimating lens (35) and the protective lens (36), and the welding wire (31) is conveyed to the welding part through the wire collimator (32); the powder feeding port (37) is connected to the powder feeder (2) and can convey powder to the welding part; the CCD camera (33) can monitor the surface state of the molten pool during the narrow-gap structure laser welding in real time, so as to realize the precise coupling of the annular laser beam, the welding wire and the powder; the special laser head for wire and powder mixing welding (3) is provided with a protective gas channel (39) to realize the coaxial protection of the gas during the wire and powder mixing laser welding process of the thick plate narrow-gap structure; the control system (5) includes an intelligent welding knowledge base, which can determine the optimal welding parameters based on the weld quality monitored by the CCD camera (33) and the groove size of the narrow-gap structure; at the same time, the control system (5) adjusts the powder feeding speed and the wire feeding speed in real time to realize the coordinated control and automatic start and stop of the two, and ensure the stability of the welding process and the quality of the weld; the CCD camera can monitor the phenomenon of incomplete fusion on the side wall during the welding process in real time, and for this phenomenon, the spot diameter, defocus amount, laser power, powder feeding amount and wire feeding speed can be adjusted in real time; if it is monitored that there is a phenomenon of incomplete fusion on the side wall or poor weld quality in the previous weld when welding the next weld, powder can be pre-sprayed at the defect, and local laser repair can be carried out during the subsequent welding process to ensure the quality of the previous weld; The CCD camera can monitor the change of the groove size of the narrow-gap structure (38) in real time and autonomously select the welding parameters and welding method for the next weld based on the intelligent welding knowledge base system.

2. A special laser welding device for thick plate narrow-gap structure based on coaxial mixing of wire and powder according to claim 1, characterized in that: The special laser head for wire-powder hybrid welding has multiple working modes, including coaxial welding of light-wire-powder, single laser welding, light-wire welding and light-powder welding, and can autonomously select the welding mode based on welding requirements; the special laser head for wire-powder hybrid welding also has the functions of local repair and enhancement of weld defects, can realize local repair of defects occurring during the welding process, and can also achieve reinforcement of the weld by adjusting the powder composition, improving the welding quality.

3. A special laser welding device for thick plate narrow-gap structure based on coaxial mixing of wire and powder according to claim 1, characterized in that: The intelligent welding knowledge base can automatically select the powder material and the composition and content of the welding wire suitable for the base material. The powder composition can be corrosion-resistant powder, high-temperature-resistant powder, etc., to achieve high-strength and high-quality welding of the narrow-gap structure.

4. A special laser welding device for thick plate narrow-gap structure based on coaxial mixing of wire and powder according to claim 1, characterized in that: The laser can be a continuous laser or a pulsed laser, and a suitable laser is selected according to the actual application scenario to meet different welding requirements.

5. A narrow-gap structure wire-powder coaxial laser welding method implemented by a special laser welding device for thick plate narrow-gap structure based on coaxial mixing of wire and powder according to claim 1, characterized in that, the method includes the following steps: Step 1, use the visual inspection method to detect the required welding part, and adjust the position of the special laser head (3) for wire-powder hybrid welding by means of the motion mechanism (1). Autonomously select the powder material and the welding wire composition through the intelligent welding knowledge base, and load the selected powder material and welding wire into the powder feeder (2) and the wire feeder; Step 2, the control system controls the powder feeder (2), the wire feeder and the laser (6) to start, and starts welding the narrow-gap structure according to the best welding process and parameters obtained from the intelligent welding knowledge base; Step 3, based on the weld quality and the skin opening size of the narrow-gap structure, select the welding parameters based on the intelligent welding knowledge base system, and adjust the welding parameters, powder feeding speed and wire feeding speed in real time to ensure the quality and stability of the weld; Step 4, if defects are detected in the weld in real time by the CCD camera (33) when welding the next weld, perform the operation of powder feeding repair, and realize the repair of the previous weld by spraying powder at the defect.

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