Method and device for special laser welding of thick plate narrow gap structure based on coaxial mixing of silk powderTechnical Field
The invention relates to the field of aluminum alloy welding, in particular to a special laser welding method and device for a thick plate narrow gap structure based on coaxial mixing of wire and powder.
Background
In recent years, a narrow gap laser welding technology is considered as a key core technology for solving the problem of complex structure welding of a medium plate, combines the advantages of the narrow gap welding technology and the laser welding technology, and can effectively improve the welding deformation and the residual stress level of a welding joint, so that the narrow gap laser welding technology has great application potential in the field of medium plate welding. The narrow-gap laser filler wire welding can improve the adaptability of the laser welding to the assembly precision of the workpiece by introducing the welding wire, so that the disadvantage of single laser welding is overcome, and on the other hand, the welding wire can also supplement alloy elements for the welding seam by introducing the welding wire, so that the comprehensive performance of the joint is improved.
However, conventional narrow gap laser filler wire welding uses a paraxial wire feed approach to the welding, i.e., the laser and wire feed are two independent systems and have axial differences in space. Although the design cost is reduced to a certain extent, the mode also has the problems that firstly, the welding stability is poor due to the fact that light and wires are not coaxial, namely, the shape of a molten pool is directly influenced by tiny relative displacement fluctuation, so that the welding quality is influenced, secondly, a welding wire is only irradiated by one side of laser, so that the material is heated unevenly, high heat input can also cause continuous high temperature and slow cooling of the molten pool, finally, the fusion property of the side wall of a welding line is influenced by the size of a groove, and the defects of unfused side wall of the welding line, air holes, root cracks and the like are not easy to occur in the welding process.
In order to solve the above problems, this patent proposes a wire-powder coaxial laser welding method, and designs a special laser welding device for a narrow gap structure. The method realizes effective welding of the narrow gap structure through wire-powder hybrid welding. Meanwhile, the stability and the welding quality of the welding process are improved through coordination and adjustment of the intelligent control system. The special laser welding device has important application value and technical innovation significance in the field of laser welding of thick plate narrow-gap structures.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a special laser welding method and device for a thick plate narrow gap structure based on coaxial mixing of silk powder. The device comprises a moving mechanism, a powder feeder, a laser head special for wire-powder hybrid welding, a control system, a laser and other components. The special laser head for wire-powder hybrid welding comprises a welding wire collimator, a CCD camera, a powder feeding port, a shielding gas channel, a focusing lens, a reflecting mirror, a collimating lens, an optical fiber access module and the like, and can realize accurate coupling of wires, powder materials and laser beams. In addition, the control system is provided with a welding knowledge base, and welding parameters are adjusted according to monitoring results, so that automatic coordination adjustment of the powder feeding speed and the wire feeding speed is realized. The device has various working modes, has the functions of local repair and enhancement of weld defects, and can adapt to different base materials and powder materials, thereby realizing high-strength and high-quality welding with a narrow gap structure.
In order to achieve the above object, the present invention is realized by the following technical scheme.
A thick plate narrow gap structure special laser welding device based on coaxial wire powder mixing mainly comprises a motion mechanism, a powder feeder, a wire powder mixing welding special laser head, a control system and a laser;
Further, the control system is connected with the motion mechanism, the powder feeder and the laser head and the laser special for wire-powder hybrid welding, and is used for controlling the operation of each system and the selection of welding parameters, and simultaneously monitoring the welding quality of the narrow-gap structure in real time.
Further, the special laser head for wire-powder hybrid welding comprises a welding wire collimator, a CCD camera, a second reflecting mirror, a second collimating lens, a protective lens, a powder feeding port, a protective gas channel, a focusing lens, a first reflecting mirror, a first collimating lens and an optical fiber access module.
The laser beam is a laser beam output by the laser through the optical fiber access module, the first collimating lens is connected with the optical fiber access module, 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, the two focusing lenses opposite in direction change the laser beam into a hollow laser beam, namely an annular laser beam, the annular laser beam is converted into a laser beam perpendicular to the plate direction by the second reflecting mirror, and the annular laser beam is focused below the outlet position of the conical nozzle by the second collimating lens.
The welding wire collimator sequentially passes through the second reflecting mirror, the second collimating lens and the protective lens, the welding wire is conveyed to a part to be welded through the welding wire collimator, the powder conveying port is connected with the powder conveying device and can convey powder to the part to be welded, the CCD camera can monitor the surface state of a laser welding pool with a narrow gap structure in real time, so that precise coupling of an annular laser beam, the welding wire and the powder is realized, a protective gas channel is arranged on a special laser head for wire-powder hybrid welding, and coaxial protection of gas in a wire-powder hybrid laser welding process with a thick plate narrow gap structure is realized.
Furthermore, the control system comprises an intelligent welding knowledge base, can determine optimal welding parameters based on the weld quality monitored by the CCD camera and the groove size of the narrow-gap structure, and simultaneously, the control system adjusts the powder feeding speed and the wire feeding speed in real time, realizes cooperative regulation and control and automatic start and stop of the powder feeding speed and the wire feeding speed, and ensures the stability of the welding process and the quality of the weld.
Furthermore, 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 automatically select a welding mode based on welding requirements, and 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 in the welding process, can realize reinforcement of the weld by powder component allocation, and improves welding quality.
Further, the CCD camera can monitor the sidewall unfused phenomenon in the welding process in real time, and can regulate and control the spot diameter, defocusing amount, laser power, powder feeding amount and wire feeding speed in real time according to the sidewall unfused phenomenon, and if the phenomenon that the sidewall unfused or the quality of the welding seam is poor in the last welding seam is monitored in the process of welding the next welding seam, powder can be sprayed in advance at the defect part, and local laser repair is carried out in the subsequent welding process, so that the quality of the last welding seam is ensured.
Further, the CCD camera can monitor the change condition of the groove size of the narrow gap structure in real time, and automatically select the welding parameter and the welding mode of the next welding seam based on the intelligent welding knowledge base system.
Further, the intelligent welding knowledge base can automatically select the components and the content of the powder material of the adaptive parent metal and the welding wire, and the powder can be corrosion-resistant powder, high-temperature-resistant powder and the like so as to realize high-strength and high-quality welding of a narrow-gap structure.
Further, the laser can be a continuous laser or a pulse laser, and a proper laser is selected according to practical application scenes so as to meet different welding requirements.
A method for realizing coaxial laser welding of silk powder with a narrow gap structure by a coaxial mixed laser welding device of silk powder can be realized by the following steps:
Step one, detecting a required welding position by adopting a visual detection method, adjusting the position of a special laser head for wire-powder hybrid welding by means of a robot, automatically selecting powder materials and welding wire components through an intelligent welding knowledge base, and loading the selected powder materials and welding wires into a powder feeder and a wire feeder;
step two, the control system controls the powder feeder, the wire feeder and the laser to be started, and welding of the narrow-gap structure is started according to the optimal welding process and parameters acquired by the intelligent welding knowledge base;
thirdly, based on the weld quality and the skin opening size of the narrow gap structure, selecting welding parameters based on an intelligent welding knowledge base system, and adjusting the welding parameters, the powder feeding speed and the wire feeding speed in real time to ensure the quality and the stability of the weld;
And step four, if the next welding line is detected to have defects through a CCD camera in real time, powder feeding and repairing operations can be performed, and the repairing of the previous welding line is realized through powder spraying at the defects.
The invention has the advantages and positive effects that:
The special laser welding method and device for the thick plate narrow gap structure based on coaxial mixing of the wire and the powder have the advantages of improving the narrow gap welding quality, improving the adaptability of the device, improving the welding efficiency and the like. The device improves the welding quality of the narrow gap structure and reduces the deformation and residual stress of the welding joint by a wire-powder mixed welding mode. Meanwhile, the device has multiple working modes, supports the local repair of weld defects, meets different welding requirements and improves the welding adaptability. The intelligent control system can adjust welding parameters according to monitoring results, and cooperatively regulate and control powder feeding speed and wire feeding speed, so that welding efficiency and stability are improved. In conclusion, the special laser welding device for the thick plate narrow gap structure based on coaxial wire and powder mixing can solve the defects of unfused welding seam side walls, air holes, root cracks and the like, and has wide application prospects.
Drawings
Fig. 1 is a diagram of a special laser welding device for a thick plate narrow gap structure based on coaxial mixing of filament and powder.
Fig. 2 is a flow of a method for special laser welding of a thick plate narrow gap structure based on coaxial mixing of filament and powder.
FIG. 3 is a schematic diagram of laser powder delivery repair of weld unfused defects.
1-Movement mechanism
2-Powder feeder
The special laser head for 3-wire powder mixing welding comprises 31-welding wire, 32-welding wire collimator, 42-CCD camera, 34-second reflector, 35-second collimating lens, 36-protective lens, 37-powder feeding port, 38-narrow gap structure, 39-protective gas channel, 40-focusing lens, 41-first reflector, 42-first collimating lens, 43-laser beam and 44-optical fiber access module
5-Control system
6-Laser
Detailed Description
The present invention will be described in further detail below with reference to the drawings and examples for the purpose of facilitating understanding to those skilled in the art. It is to be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to be limiting. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.
The invention is further illustrated by a specific example.
Examples
In the example, the coaxial mixed laser welding of TC4 titanium alloy narrow-gap wire powder with the thickness of 8mm is carried out by taking the requirements of a light alloy large-thickness structural member and a high-efficiency connecting process thereof as the background.
As shown in fig. 1, the invention discloses a thick plate narrow gap structure special laser welding device based on coaxial mixing of silk powder, which mainly comprises a moving mechanism 1, a powder feeder 2, a laser head 3 special for silk powder mixing welding, a control system 5 and a laser 6.
The special laser head 3 for wire-powder hybrid welding comprises a welding wire collimator 32, a CCD camera 33, a second reflecting mirror 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 reflecting mirror 41, a first collimating lens 42 and an optical fiber access module 44, wherein the laser beam 43 is a laser beam output by the optical fiber access module 44, the first collimating lens 42 is connected with the optical fiber access module 44, the diameter of the laser beam 43 is enlarged after passing through the first collimating lens 42, the first reflecting mirror 41 deflects the angle of the laser beam to the focusing lens, the two focusing lenses 37 with opposite directions convert the laser beam into a hollow laser beam, namely an annular laser beam, the second reflecting mirror 34 converts the annular laser beam into a laser beam vertical to the direction of a plate, and focuses the annular laser beam below the outlet position of a conical nozzle through the second collimating lens 35;
The welding wire collimator sequentially passes through the second reflecting mirror 34, the second collimating lens 35 and the protective lens 36, the welding wire 31 is conveyed to a part to be welded through the welding wire collimator 32, the powder conveying port 37 is connected with the powder conveying device 2 and can convey powder to the part to be welded, the CCD camera 33 can monitor the surface state of a laser welding pool with a narrow gap structure in real time so as to realize precise coupling of annular laser beams, welding wires and powder, the special laser head 3 for wire-powder hybrid welding is provided with the protective gas channel 39 to realize coaxial protection of thick plate narrow gap structure wire-powder hybrid laser welding process gas, the control system 5 comprises an intelligent welding knowledge base and can determine optimal welding parameters based on the welding seam quality and the narrow gap structure groove size monitored by the CCD camera 33, meanwhile, the control system 5 adjusts the powder conveying speed and the wire conveying speed in real time, realizes cooperative regulation and automatic start-stop of the two, and ensures the stability of the welding process and the welding seam quality.
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 automatically select a welding mode based on welding requirements, and 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 in the welding process, can realize reinforcement of the weld by powder component allocation, and improves welding quality.
The CCD camera can monitor the sidewall unfused phenomenon in the welding process in real time, can regulate and control the spot diameter, the defocus amount, the laser power, the powder feeding amount and the wire feeding speed in real time aiming at the phenomenon, and can pre-spray powder at the defect position and perform local laser repair in the subsequent welding process if the phenomenon that the sidewall unfused or the weld quality is poor in the last weld is monitored when the next weld is welded, so that the quality of the last weld is ensured.
The CCD camera can monitor the change condition of the groove size of the narrow gap structure 38 in real time, and autonomously select the welding parameter and the welding mode of the next welding seam based on the intelligent welding knowledge base system.
The intelligent welding knowledge base can automatically select the components and the content of the powder material of the adaptive parent metal and the welding wire, and the powder components can be corrosion-resistant powder, high-temperature-resistant powder and the like so as to realize high-strength and high-quality welding of a narrow-gap structure.
The laser can be a continuous laser or a pulse laser, and a proper laser is selected according to practical application scenes so as to meet different welding requirements.
The method for realizing the coaxial laser welding of the narrow-gap structure wire powder of the thick plate narrow-gap structure by using the special laser welding device based on coaxial mixing of the wire powder comprises the following steps:
Step one, detecting a required welding position by adopting a visual detection method, adjusting the position of a special laser head 3 for wire-powder hybrid welding by means of a moving mechanism 1, automatically selecting powder materials and welding wire components through an intelligent welding knowledge base, and loading the selected powder materials and welding wires into a powder feeder 2 and a wire feeder;
Step two, the control system controls the powder feeder 2, the wire feeder and the laser 6 to be started, and welding of the narrow gap structure is started according to the optimal welding process and parameters acquired by the intelligent welding knowledge base;
thirdly, based on the weld quality and the skin opening size of the narrow gap structure, selecting welding parameters based on an intelligent welding knowledge base system, and adjusting the welding parameters, the powder feeding speed and the wire feeding speed in real time to ensure the quality and the stability of the weld;
And step four, if the next welding line is detected to have defects in real time through the CCD camera 33, the operation of powder feeding and repairing can be performed, and the repairing of the previous welding line is realized through powder spraying at the defects.
It is to be understood that the foregoing examples of the invention are provided for the purpose of illustration only and are not intended to limit the scope of the invention, which is defined by the claims, since modifications in both the detailed description and the application scope of the invention will become apparent to those skilled in the art upon consideration of the teachings of the invention. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the invention are desired to be protected by the following claims.