Automatic laser sealing ring welding equipment for end of thin-walled tube

Abstract

The invention relates to the technical field of automatic welding equipment, and particularly discloses thin-walled tube end automatic laser sealing ring welding equipment which comprises a laser welding gun assembly, an end plug positioning assembly, a pushing assembly, a clamping rotating assembly, an in-place sensor and a welding cavity. The laser welding gun assembly is used for welding the end of the thin-walled tube in the welding cavity by introducing a laser beam, a clamping rotating assembly and an end plug positioning assembly are arranged at the input end and the output end of the welding cavity correspondingly, the end plug positioning assembly is used for positioning an end plug, and the clamping rotating assembly is used for clamping and rotating the thin-walled tube; the in-place sensor is arranged between the clamping and rotating assembly and the welding cavity and used for detecting in-place signals of the thin-walled pipe, the pushing assembly is connected to the side, away from the welding cavity, of the end plug positioning assembly, automatic welding under the protective atmosphere can be achieved, and the welding precision and efficiency are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automatic welding equipment, and particularly relates to a thin-walled pipe end automatic laser sealing ring welding equipment. BACKGROUND

[0002] At present, the welding of thin-walled pipes and end plugs is widely used in high-end manufacturing fields such as nuclear industry, aerospace, medical devices and precision instruments. In particular, in the manufacturing process of nuclear fuel assemblies, sensor pipelines and sealed cavities, the closed welding of thin-walled pipe ends has important quality and safety requirements. Due to the structural characteristics and high requirements for the use environment, the welding process must ensure that the joint has high airtightness, stable weld quality and is not easy to deform. However, the existing welding methods generally rely on manual operation or semi-automatic equipment, which not only has problems such as poor welding consistency, low process repeatability and low production efficiency, but also is difficult to accurately control the welding heat input, which easily leads to defects such as thin-walled pipe thermal deformation, weld protrusion or weld-through. Therefore, developing an automatic welding device with high precision, high consistency and suitable for batch production has become a technical problem to be solved.

[0003] The traditional thin-walled pipe end plug welding method mostly adopts manual TIG welding or manual ring welding with simple mechanical clamps. The operator needs to frequently intervene in the welding process, manually adjusts the welding position, welding gun angle and welding speed, and is easily disturbed by human factors. In addition, the traditional device does not have a standardized feeding and positioning mechanism, the thin-walled pipe installation repeatability is poor, and the concentricity and uniformity of each weld cannot be guaranteed, which affects the welding quality. More importantly, the traditional welding environment often cannot form a sealed space, and cannot implement vacuum pumping or inert gas protection on the welding area, which easily leads to defects such as oxidation and porosity of the weld, especially in the working condition requiring high airtightness, which cannot meet the product requirements.

[0004] In addition, the traditional method also has certain limitations in environmental protection and energy utilization. The gas protection efficiency is low during the welding process, which easily causes waste of argon or helium resources, and the unstable welding current control not only increases energy consumption, but also reduces the green level of manufacturing. A large amount of smoke and harmful gas is released during the welding process, and the traditional open operation is not conducive to pollution control and personnel safety in the welding area. Moreover, factories lacking efficient dust removal equipment are difficult to meet the environmental protection standards. SUMMARY

[0005] The present application relates to the technical field of automatic welding equipment, and particularly relates to a thin-walled pipe end automatic laser sealing ring welding equipment.

[0006] The purpose of the present application can be achieved by the following technical solutions: The application discloses a kind of thin-walled pipe end automatic laser sealing ring welding equipment, including laser welding gun assembly, end plug positioning assembly, push assembly, clamping rotating assembly, in-place sensor and welding chamber, the laser welding gun assembly is connected in the upper of welding chamber, the laser welding gun assembly is welded to the thin-walled pipe end in welding chamber by leading-in laser beam, the input and output of the welding chamber are respectively provided with clamping rotating assembly and end plug positioning assembly, the end plug positioning assembly is used to position end plug, the clamping rotating assembly is used to clamp and rotate thin-walled pipe, the in-place sensor is arranged between clamping rotating assembly and welding chamber, the in-place sensor is used to detect thin-walled pipe in-place signal, the push assembly is connected in end plug positioning assembly side away from welding chamber.

[0007] Further scheme, the welding chamber is provided with pipe mouth flange near clamping rotating assembly side, the welding chamber is provided with positioning assembly interface near push assembly side, the top of the welding chamber is provided with transmission glass, the cavity wall of the welding chamber on push assembly side is further provided with vacuum extraction interface and protective gas interface, welding chamber is communicated with vacuum extraction equipment through vacuum extraction interface, welding chamber is communicated with protective gas injection equipment through protective gas interface.

[0008] Further scheme, the end plug positioning assembly includes end plug positioning block, disc spring, thrust bearing, ball bearing, sleeve and vacuum connector, the inside of the end plug positioning block is hollow, one end of the end plug positioning block is provided with shaft shoulder, the other end is inserted into sleeve and extends out of sleeve, and the ball bearing is arranged between the sleeve, the other end of the end plug positioning block is rolling connected with the sleeve through the ball bearing, the disc spring and the thrust bearing are connected between one end of the sleeve and the shaft shoulder of the end plug positioning block, the shaft shoulder of the end plug positioning block is elastically and slidingly connected with the sleeve through the disc spring and the thrust bearing, the other end of the end plug positioning block extends into one end of the vacuum connector, and is connected with the inner wall of one end of the vacuum connector through dynamic sealing, the end face of one end of the vacuum connector is connected with the other end of the sleeve through another disc spring and thrust bearing in turn, the inside of the end plug positioning block is communicated with the vacuum connector, the inside of the end plug positioning block is vacuumized through the vacuum connector, and the shaft shoulder end of the end plug positioning block is inserted into the positioning assembly interface.

[0009] Further scheme, the push assembly includes air cylinder and connecting barrel, one end of the connecting barrel is connected with the other end of the vacuum connector, the other end of the connecting barrel is connected with the air cylinder, and the connecting barrel moves the vacuum connector by the air cylinder.

[0010] Further scheme, the vacuum connector is connected with pipeline away from sleeve end, the pipeline is slidingly and sealingly connected with the vacuum connector, and the connecting barrel is provided with avoiding hole for the pipeline.

[0011] In a further aspect, the welding chamber is provided with an observation assembly on the side away from the shielding gas interface.

[0012] In a further aspect, the observation assembly comprises a visual lens, a light channel, a coaxial LED light source, a CCD camera, a semi-transparent semi-reflective light splitting sheet and a protective glass, the welding chamber is provided with an opening on the side away from the shielding gas interface, the protective glass is slidably connected to the opening, a dynamic seal is arranged between the protective glass and the outer wall of the welding chamber, the light channel is connected to the side of the protective glass away from the welding chamber, the CCD camera is connected to the side of the light channel away from the protective glass, two semi-reflective light splitting sheets are connected in the light channel, and the coaxial LED light source and the visual lens are coaxially connected to the CCD camera through the two semi-reflective light splitting sheets.

[0013] In a further aspect, the lower end of the CCD camera is connected to an adjusting sliding platform, and the adjusting sliding platform is used for light adjustment of the CCD camera.

[0014] In a further aspect, the clamping and rotating assembly is a pneumatic rotating cylinder clamp or a hollow pneumatic rotating chuck.

[0015] In a further aspect, the thin-walled pipe end automatic laser sealing ring welding equipment further comprises a water cooler, an electrical integrated cabinet, a welding machine controller and a laser, the laser is connected with the laser welding gun assembly, the laser is used for sending a laser beam to the laser welding gun assembly, the water cooler is connected with the laser, the water cooler is used for cooling the laser, the welding machine controller is electrically connected with the laser, the water cooler, the laser welding gun assembly, the end plug positioning assembly, the pushing assembly, the clamping and rotating assembly and the in-place sensor, respectively, for controlling the laser to emit laser, the water cooler to cool, the end plug positioning assembly to position, the laser welding gun assembly to weld, the pushing assembly to push, the clamping and rotating assembly to clamp and rotate, and the in-place sensor to transmit an in-place signal, and the electrical integrated cabinet is used for integrating the water cooler, the welding machine controller, the laser, the laser welding gun assembly, the end plug positioning assembly, the pushing assembly, the clamping and rotating assembly, the in-place sensor and the electrical pipelines connected on the welding chamber.

[0016] The beneficial effects of the present application are as follows: When the thin-walled pipe end and the end plug are transported together to the welding chamber for welding, during the transportation process, the end plug positioning assembly positions the end plug after receiving the in-place signal by the in-place sensor, the clamping and rotating assembly clamps the thin-walled pipe to drive the thin-walled pipe end and the end plug to rotate together, and the laser welding gun assembly provided is used for fixing and welding the end plug embedded in the thin-walled pipe end, so that the operation process is simple, the thin-walled pipe is automatically centered and positioned, and precise clamping and welding are realized without manual intervention, the welding position can be automatically identified by the sensor, and the automatic planning of the feeding distance, the positioning time, the clamping time and the welding time can be controlled, the operation efficiency and the welding consistency are significantly improved, the quality fluctuation caused by human factors is reduced, the demand of large-batch continuous operation is met, and the automatic production process can be used.

[0017] The welding chamber can be designed as a fully sealed type, the travel is protected by an argon protection atmosphere through a vacuum argon filling device and a vacuum pumping device, the welding area is ensured to be in an oxygen-free state during the welding process, and the welding seam is effectively prevented from being oxidized. The laser welding gun assembly can adopt a high-precision laser ranging and height adjustment module to accurately control the distance between the laser welding head and the welding seam, so that the welding seam is flat, free of pores and splashes, has excellent air tightness after welding, and fully meets the use requirements in high-demand working conditions such as vacuum and pressure vessels.

[0018] To solve the problem of axial deformation caused by uneven heat input of the thin-walled pipe during welding, a disc spring structure is adopted to provide a buffer stroke during welding, so that stress concentration caused by welding thermal expansion can be automatically absorbed, welding seam deformation and concave can be effectively controlled, and the size accuracy and mechanical properties of the welding seam can be improved. While the welding quality is maintained, the post-welding finishing requirement is reduced, and the stability of the overall welding process is improved.

[0019] The welding thin-walled pipe end in-place signal and the welding condition are fed back by the CCD camera and the in-place sensor, the preset speed clamping, rotating, positioning and welding process are executed according to the received data feedback, the operation is simple, the whole process only needs to insert the thin-walled pipe into the machine head, and the remaining welding process can be completed automatically and with high quality, so that the process flow is greatly simplified and the operation threshold is reduced.

[0020] The sealing ring welding equipment can be seamlessly integrated with the existing production line, can be operated as an independent working unit or an embedded device, has good adaptability and universality, and is especially suitable for automatic welding manufacturing requirements of nuclear fuel assemblies, precision electronic tubes, aerospace thin-walled containers and other types of products.

[0021] The present application combines the real-time image monitoring of CCD camera, i.e. digital camera with charge-coupled device image sensor, and the bar code identification technology, and can realize the collection, recording and analysis of the whole welding state, and can realize the binding of production information and the archiving of quality data of each thin-walled pipe, and is convenient for subsequent tracing and process analysis. The function has important significance for high-quality manufacturing process. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, a brief introduction will be given below to the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0023] Figure 1 is a schematic diagram of a thin-walled pipe end automatic laser sealing ring welding equipment in an embodiment of the present application; Figure 2 is a schematic diagram of a welding chamber connection in an embodiment of the present application; Figure 3 is a schematic diagram of a cross-sectional connection of an end plug positioning assembly in an embodiment of the present application; Figure 4 is a schematic diagram of a cylinder connection in an embodiment of the present application; Figure 5 is a schematic diagram of a cross-sectional connection of an observation assembly in an embodiment of the present application; Figure 6 is a schematic diagram of a cross-sectional connection of a welding chamber in an embodiment of the present application; Figure 7 is a schematic diagram of a cross-sectional connection of a thin-walled pipe end and an end plug after welding in an embodiment of the present application.

[0024] In the figure: 1, laser welding gun assembly; 2, end plug positioning assembly; 21, end plug positioning block; 22, disc spring; 23, thrust bearing; 24, ball bearing; 25, sleeve; 26, vacuum connector; 3, pushing assembly; 31, cylinder; 32, connecting barrel; 4, clamping and rotating assembly; 5, in-place sensor; 6, welding chamber; 61, pipe flange; 62, positioning assembly interface; 63, transmission glass; 64, vacuum extraction interface; 65, protective gas interface; 7, observation assembly; 71, visual lens; 72, light channel; 73, coaxial LED light source; 74, CCD camera; 75, protective glass; 76, adjusting slide; 8, water cooling machine; 9, electrical integrated cabinet; 10, welding machine controller; 11, laser; 12, machine head base. DETAILED DESCRIPTION

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] like Figure 1 As shown, an automatic laser sealing ring welding device for thin-walled tube ends includes a laser welding gun assembly 1, an end plug positioning assembly 2, a pushing assembly 3, a clamping and rotating assembly 4, a positioning sensor 5, and a welding chamber 6. The laser welding gun assembly 1 is connected to the welding chamber 6. The laser welding gun assembly 1 welds the thin-walled tube end in the welding chamber 6 by introducing a laser beam. The input and output ends of the welding chamber 6 are respectively provided with the clamping and rotating assembly 4 and the end plug positioning assembly 2. The end plug positioning assembly 2 is used to position the end plug, and the clamping and rotating assembly 4 is used to clamp and rotate the thin-walled tube. The positioning sensor 5 is located between the clamping and rotating assembly 4 and the welding chamber 6. The positioning sensor 5 is used to detect the positioning signal of the thin-walled tube. The pushing assembly 3 is connected to the side of the end plug positioning assembly 2 away from the welding chamber 6.

[0027] Its working principle is as follows: the laser beam emitted from the laser welding gun assembly 1 (i.e., the laser welding head) enters the welding chamber 6 through the open working window at the top of the welding chamber 6. The end plug positioning assembly 2 is used for positioning the thin-walled tube during insertion. To achieve automatic welding, a ring-shaped positioning sensor 5 is equipped at the front end of the chamber. When the thin-walled tube begins to enter the positioning sensor 5, the positioning sensor 5 sends a signal to the device used to push the thin-walled tube into the welding chamber 6. The device used to push the thin-walled tube into the welding chamber 6 controls the feeding distance of the thin-walled tube. Generally, this device can be an electric cylinder, which works in conjunction with the positioning position of the end plug positioning assembly 2 to automatically position the thin-walled tube and complete the feeding. The pushing assembly 3 presses the end plug positioning assembly 2 before welding and then disengages. The laser welding gun assembly 1 does not use filler wire during the welding process. By melting the end plug material, the weld seam achieves the required smoothness.

[0028] like Figure 6As shown, a pipe flange 61 is provided on the side of the welding chamber 6 near the clamping and rotating assembly 4, and a positioning assembly interface 62 is provided on the side of the welding chamber 6 near the pushing assembly 3. A transmissive glass 63 is provided on the top of the welding chamber 6. A vacuum interface 64 and a protective gas interface 65 are also provided on the wall of the welding chamber 6 on the side of the pushing assembly 3. The welding chamber 6 is connected to a vacuum pump through the vacuum interface 64 and to a protective gas injection device through the protective gas interface 65. The welding chamber 6 and its internal components are made of stainless steel, ensuring that the protective gas flow has no dead corners within the chamber, and that there is no oxidation of the weld, thin-walled pipe wall, and end plug. It can withstand a high pressure of 5MPa. The top of the welding chamber 6 is an open working window, sealed with a top transmissive glass 63 for chamber sealing and laser transmission. Multiple flange holes are provided on the chamber wall to install different functional components, including the positioning assembly interface 62, the pipe flange 61, the vacuum interface 64, and the protective gas interface 65. The end plug positioning assembly 2 is connected to the welding chamber 6 through the positioning assembly interface 62. The thin-walled tube enters the welding chamber 6 through the pipe flange 61. The welding chamber 6 is connected to the vacuum and argon purging lines in the electrical integrated cabinet 9 via the vacuum port 64 and the protective gas port 65, respectively, to ensure the atmosphere within the chamber during welding. The welding chamber 6 is sealed to all components; the positioning component port 62 and the pipe flange 61 use dynamic seals, while the top translucent glass 63, the vacuum port 64, and the protective gas port 65 use static seals. Therefore, the welding chamber 6 is a fully sealed structure, suitable for welding in high-pressure environments. All connected components of the welding chamber 6 are detachable, allowing for cleaning of the interior and ensuring its cleanliness.

[0029] like Figure 3 As shown, the end plug positioning assembly 2 includes an end plug positioning block 21, a disc spring 22, a thrust bearing 23, a ball bearing 24, a sleeve 25, and a vacuum connector 26. The end plug positioning block 21 is hollow inside. One end of the end plug positioning block 21 is provided with a shoulder, and the other end is inserted into the sleeve 25 and extends out of the sleeve 25. A ball bearing 24 is provided between the end plug positioning block 21 and the sleeve 25. The other end of the end plug positioning block 21 is tumblingly connected to the sleeve 25 through the ball bearing 24. A disc spring 22 and a thrust bearing 23 are connected between one end of the sleeve 25 and the shoulder of the end plug positioning block 21. The shoulder of the end plug is elastically and slidably connected to the sleeve 25 via a disc spring 22 and a thrust bearing 23. The other end of the end plug positioning block 21 extends into one end of the vacuum connector 26 and is connected to the inner wall of one end of the vacuum connector 26 via a dynamic seal. One end face of the vacuum connector 26 is connected to the other end of the sleeve 25 via another disc spring 22 and a thrust bearing 23. The vacuum connector 26 communicates with the hollow interior of the end plug positioning block 21. The hollow interior of the end plug positioning block 21 is evacuated through the vacuum connector 26. One end of the shoulder of the end plug positioning block 21 is inserted into the positioning component interface 62.

[0030] The welding end-plug positioning block 21 is used to position the thin-walled tube. During welding, it directly contacts the end plug and rotates with the thin-walled tube. A ball bearing 24 ensures the end-plug positioning block 21 rotates normally within the sleeve 25. A thrust bearing 23 and a disc spring 22 work in conjunction with the pushing assembly 3 to compensate for thermal expansion during welding, ensuring weld quality. Before welding, the fit between the end plug and the end-plug positioning block 21 is checked. The end-plug positioning block 21 rotates freely with the thin-walled tube during welding and provides timely heat conduction. It is made of martensitic 350 stainless steel. A freely rotating vacuum connector 26 is installed at the tail of the end-plug positioning block 21, connected to a vacuum generator. Vacuuming further removes gas from inside the end-plug positioning block 21, preventing oxidation during welding and ensuring proper fit between the end plug, the end-plug positioning block 21, and the thin-walled tube, guaranteeing the end plug is installed correctly.

[0031] like Figure 4 As shown, the pushing component 3 includes a cylinder 31 and a connecting cylinder 32. One end of the connecting cylinder 32 is connected to the other end of the vacuum connector 26, and the other end of the connecting cylinder 32 is connected to the cylinder 31. The connecting cylinder 32 pushes the vacuum connector 26 to move through the cylinder 31.

[0032] See Figure 3 As shown, cylinder 31 pushes connecting cylinder 32 to press end plug positioning block 21. The main purpose of this step is to prevent deviation in the welding position when the thin-walled tube is inserted due to the presence of pushing component 3. The thin-walled tube is inserted through pipe flange 61. After the end plug and end plug positioning block 21 are tightly fitted, clamping and rotating component 4 clamps the thin-walled tube. Vacuum argon filling operation is performed in welding chamber 6. Vacuum generator starts working to evacuate the positioning tube. Clamping and rotating component 4 starts to rotate. Cylinder 31 drives thermal compensator to retract. Since the chamber is in an argon environment and the end plug positioning block 21 is in a vacuum, the pressure difference ensures that the end plug and end plug positioning block 21 are tightly fitted. The thermal expansion during welding is compensated for by the elastic deformation of two pairs of disc springs 22 on end plug positioning block 21, avoiding weld bulging and reducing deformation.

[0033] In some embodiments, the end of the vacuum connector 26 away from the sleeve 25 is connected to a pipe, the pipe is slidably sealed to the vacuum connector 26, and the connecting sleeve 32 has a clearance hole for the pipe.

[0034] In some embodiments, an observation component 7 is provided on the side of the welding chamber 6 away from the protective gas interface 65.

[0035] In some embodiments, such as Figure 5As shown, the observation assembly 7 includes a viewing lens 71, a light channel 72, a coaxial LED light source 73, a CCD camera 74, a semi-reflective beam splitter, and a protective glass 75. An opening is provided on the side of the welding chamber 6 away from the shielding gas inlet 65, and the protective glass 75 is slidably connected to the opening. A dynamic seal is provided between the protective glass 75 and the outer wall of the welding chamber 6. The light channel 72 is connected to the side of the protective glass 75 away from the welding chamber 6, and the CCD camera 74 is connected to the side of the light channel 72 away from the protective glass 75. Two semi-reflective beam splitters are connected within the light channel 72. The coaxial LED light source 73 and the viewing lens 71 are coaxially connected to the CCD camera 74 through the two semi-reflective beam splitters, respectively. The observation assembly 7 is installed on the side of the welding chamber 6. The CCD camera 74 observes the interior of the welding chamber 6 through the observation port (the aforementioned opening) and the protective glass 75 at the opening, transmitting information such as the weld seam, laser spot position, and welding process to the industrial control system of the welding machine controller 10 for auxiliary adjustment. The visual lens 71 allows for direct observation, and the CCD camera 74 is equipped with a coaxial LED light source 73, providing parallel light rays that are completely aligned with its lens axis to enhance the brightness of the observation area and assist in observation. A protective glass 75 is installed between the observation assembly 7 and the welding chamber 6. This protective glass 75 can be controlled by rotating a handle to block the reflective path within the chamber, protecting against damage from scattered laser light, high temperatures, and high pressures, and preventing damage to the lens and other components from welding slag spatter.

[0036] In some embodiments, an adjustment slide 76 is connected to the lower end of the CCD camera 74, and the adjustment slide 76 is used for adjusting the light of the CCD camera 74. The CCD camera 74 is fixed on the sliding end of the adjustment slide 76 to adjust the observation position.

[0037] In some embodiments, the clamping and rotating assembly 4 is a pneumatic rotary collet or a pneumatic rotary chuck. The pneumatic rotary collet uses multi-lobed jaws customized to the workpiece diameter to clamp the workpiece, and the clamping force is adjustable. The pneumatic rotary collet can use an AC servo motor and a precision RV reducer to drive the thin-walled tube to rotate via a toothed belt. The parts of the end plug positioning assembly 2 and the clamping and rotating assembly 4 that contact the workpiece are made of stainless steel or PBT engineering plastic to ensure no elemental contamination of the workpiece, and are treated with chamfering and rounding to ensure that the surface of the thin-walled tube is not scratched during welding and conveying.

[0038] The automatic laser sealing ring welding equipment for thin-walled tube ends serves as the core execution unit for precise welding. The laser welding torch assembly 1 consists of a laser welding head and a welding torch height adjustment mechanism. This mechanism employs a high-precision single-axis module with a built-in ball screw and linear guide pair, driven by a servo motor. It automatically adjusts and fixes the position of the laser welding head relative to the weld seam, achieving precise adjustment of the laser welding head's height from the workpiece. It can be paired with a laser ranging system for high-precision displacement measurement. The laser ranging system uses a red semiconductor laser as the light source with a wavelength of 655nm, within the visible light range. This allows operators to visually see the laser spot position during measurement, facilitating installation, debugging, and alignment with the object being measured, thus improving the convenience and accuracy of the measurement. Green, orange, and red / green LED indicators are provided to indicate laser emission warnings, simulated range, and reference distance, respectively. Operators can quickly understand the sensor's operating status through these indicators, facilitating timely detection and troubleshooting.

[0039] See Figure 1 As shown, the sealing ring welding equipment can be installed on the machine head base 12. The machine head base 12 can be assembled by welding, and the welding stress is eliminated by two heat treatments. It has an aesthetically pleasing appearance and a strong and stable structure. Four casters are installed at the bottom, and the height can be adjusted within 100mm. The welding chamber 6, the clamping and rotating assembly 4, the pushing assembly 3, etc. are all machined with positioning grooves and equipped with high-precision positioning keys. They are installed on the precision-machined machine head base 12, allowing for fine-tuning back and forth, and are well-secured. All components are durable and do not deform.

[0040] In addition, a tail vacuum device is installed at the non-welded end of the thin-walled tube to evacuate the non-welded end during welding, preventing oxidation inside the tube during welding. The process is as follows: before welding, the vacuum device seals the non-welded end and evacuates the tube. When the set vacuum level is reached, the end plug at the welding end begins welding with the thin-walled tube. During production, the negative pressure inside the thin-walled tube is above 27 inHg (92 kPa). After welding is completed, the thin-walled tube is removed.

[0041] An automatic laser sealing ring welding device for thin-walled tube ends further includes a water chiller 8, an electrical integrated cabinet 9, a welding machine controller 10, and a laser 11. The laser 11 is connected to a laser welding gun assembly 1 and is used to send a laser beam to the laser welding gun assembly 1. The water chiller 8 is connected to the laser 11 and is used to cool the laser 11. The welding machine controller 10 is electrically connected to the laser 11, the water chiller 8, the laser welding gun assembly 1, the end plug positioning assembly 2, the pushing assembly 3, the clamping rotation assembly 4, and the position sensor 5, respectively, and is used to control the laser 11 to emit laser light, the water chiller 8 to cool the end plug, the end plug positioning assembly 2 to position, the laser welding gun assembly 1 to weld, the pushing assembly 3 to push, the clamping rotation assembly 4 to clamp and rotate, and the position sensor 5 to transmit position signals. The electrical integrated cabinet 9 is used to integrate the electrical wiring connected to the water chiller 8, the welding machine controller 10, the laser 11, the laser welding gun assembly 1, the end plug positioning assembly 2, the pushing assembly 3, the clamping rotation assembly 4, the position sensor 5, and the welding chamber 6.

[0042] The welding machine controller 10, with a CNC system at its core, integrates laser 11 control, motion control, and CCD camera monitoring to form an integrated operation control system for observing and controlling welding parameters and motion mechanisms. The welding machine controller 10 can not only control various electrical components and mechanical parts to work according to preset times and parameters, and perform welding tests and calibrations, but also complete data acquisition during the welding process. With a unique barcode on each thin-walled tube end and a barcode scanning device, the actual working parameters of each thin-walled tube are recorded, saved, and archived for technical traceability. The control system program of the welding machine controller 10 includes parameters such as fluctuation limits. When parameters such as laser power and welding speed fluctuate beyond the normal range, the equipment will issue an alarm and prompt. The welding machine controller 10 can also calibrate laser power and welding machine chuck speed.

[0043] The electrical integrated cabinet 9 contains the pneumatic system and the electrical control system of the circumferential welding equipment. These two systems are integrated into one cabinet, installed at the rear of the machine head base 12, to ensure power supply and atmosphere establishment in the welding chamber 6 during the welding process. Connected by profile fittings, the structure is compact and occupies little space. The electrical system has a fault diagnosis function, displaying the diagnostic results on the screen when a fault occurs. The system also features a pre-alarm function, monitoring the action and status of individual electrical components and mechanical parts, and providing error alarms. All motor components are equipped with grounding protection. Since an argon atmosphere is required for welding, this is achieved by first creating a certain degree of vacuum in the welding chamber 6 and then filling it with argon. The gas path system is a vacuum argon-filling system, consisting of a vacuum pump set, control valves, pipelines, and detection elements. The pipelines are divided into vacuum extraction pipelines, argon filling pipelines, exhaust pipelines, and water / oxygen detection pipelines. After argon filling, the water / oxygen content in the welding chamber 6 is measured to ensure welding quality.

[0044] Laser 11 is used to generate a high-energy-density laser beam as the energy source for laser ring welding. After being guided and shaped by an optical system, the laser beam forms a laser spot that acts on the surface of the workpiece to be welded. Water chiller 8 is connected to laser 11 to form a cooling circuit. Water chiller 8 is used to circulate cooling medium, absorb and remove the heat generated by laser 11 during operation, maintain the temperature of the core components of laser 11 within a preset operating range, and ensure the stability of laser output parameters and the reliability of equipment operation.

[0045] Using the aforementioned automated laser sealing ring welding equipment for thin-walled tube ends, welding experiments were conducted on a zirconium alloy thin-walled tube with an outer diameter of 9.50 mm, an inner diameter of 8.35 mm, and a length of 4583.2 mm, and a dimensionally compatible end plug. The end plug was 20.5 mm long, with the portion pressed into the thin-walled tube having an outer diameter of 8.422 mm and a pressing length of 3.3 mm. The end plug and the thin-walled tube end were interference-fitted. Before welding, the surfaces of the metal to be welded were cleaned with anhydrous ethanol to remove moisture, oil, and other impurities. Residual liquid was wiped off with a lint-free cloth, and assembly was completed.

[0046] The welding process is as follows: First, the thin-walled tube assembled with the end plug is sent into the welding chamber 6, and its positioning signal is identified by the positioning sensor 5. The welding machine controller 10 controls the vacuum argon filling system to protect the welding area with an atmosphere. After the thin-walled tube is initially positioned, the end plug positioning block 21 begins to evacuate. Subsequently, the clamping and rotating assembly 4 is activated, the chuck clamps the thin-walled tube and begins to rotate at a predetermined speed. At the same time, a vacuum is evacuated at the open end of the thin-walled tube through a vacuum sealing device to ensure the internal atmosphere of the thin-walled tube and prevent internal oxidation. Then, the thermal compensation mechanism retracts to leave a compensation gap for welding thermal expansion.

[0047] The welding speed was set to 0.4 mm / min, the defocusing amount to +2 mm, the shielding gas flow rate to 20 L / min, and the laser power to 500 W and 600 W respectively. Two welding sessions were performed, each lasting 4.9 seconds. After welding, a delayed gas supply operation was performed to ensure the weld remained in a shielding atmosphere during cooling, effectively preventing oxidation. After welding, the tail vacuum device stopped evacuating and reset, the chuck stopped rotating and released the thin-walled tube. The thin-walled tube was then removed from welding chamber 6. Finally, the welding system was reset, ready for the next welding cycle.

[0048] Microstructure of the welded joint as follows Figure 7 As shown in the figure, the dimensions of the welded melting zone are marked with red dimension lines. Actual observation shows that the welded joint cross-section is free of defects such as porosity, cracks, unfused zones, solid inclusions, irregular contours, undercut edges, stains, or discoloration.Figure 7 Two sets of parameters were used: parameter 1, obtained from welding with a laser power of 500W, and parameter 2, obtained from welding with a laser power of 600W. The weld widths of parameters 1 and 2 were 1.2mm and 1.46mm, respectively, and the weld depth of both was 0.12mm. The reference dimension for both was 0.5mm. Through the above-described automatic welding process, the thin-walled tube end and end plug achieved a high-quality, oxidation-free, and porosity-free sealed weld. The weld formation was good, exhibiting excellent airtightness and mechanical stability, verifying the feasibility and advancement of the device and method of this invention in high-consistency, high-sealing welding applications.

[0049] This device has significant advantages in terms of structural stability and maintainability. The whole machine adopts a high-strength welded frame structure and a multi-axis precision alignment installation method to ensure long-term stable operation; all functional components are designed to be detachable, which facilitates cleaning and maintenance; the electrical control system of the welding machine controller 10 can adopt a compact layout and is equipped with multi-level safety protection functions to ensure the reliability, safety and ease of operation of the equipment during long-term operation.

[0050] In summary, this invention has achieved significant improvements in welding quality, automation level, versatility, process monitoring capabilities, and equipment reliability. It has overcome the bottlenecks of traditional manual welding and semi-automatic equipment, such as low precision, low efficiency, complex operation, and poor weld consistency. It has good industrialization prospects and application value.

[0051] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0052] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. An automatic laser sealing ring welding device for thin-walled tube ends, characterized in that, The assembly includes a laser welding gun assembly (1), an end plug positioning assembly (2), a pushing assembly (3), a clamping and rotating assembly (4), a positioning sensor (5), and a welding chamber (6). The laser welding gun assembly (1) is connected to the welding chamber (6). The laser welding gun assembly (1) welds the thin-walled tube end in the welding chamber (6) by introducing a laser beam. The input and output ends of the welding chamber (6) are respectively provided with a clamping and rotating assembly (4) and an end plug positioning assembly (2). The end plug positioning assembly (2) is used to position the end plug. The clamping and rotating assembly (4) is used to clamp and rotate the thin-walled tube. The positioning sensor (5) is located between the clamping and rotating assembly (4) and the welding chamber (6). The positioning sensor (5) is used to detect the positioning signal of the thin-walled tube. The pushing assembly (3) is connected to the side of the end plug positioning assembly (2) away from the welding chamber (6).

2. The automatic laser sealing ring welding equipment for thin-walled tube ends according to claim 1, characterized in that, The welding chamber (6) is provided with a pipe flange (61) on the side near the clamping and rotating assembly (4), and a positioning assembly interface (62) is provided on the side near the pushing assembly (3). A transmission glass (63) is provided on the top of the welding chamber (6). A vacuum port (64) and a protective gas port (65) are also provided on the wall of the welding chamber (6) on the side of the pushing assembly (3). The welding chamber (6) is connected to a vacuum pumping device through the vacuum port (64) and to a protective gas injection device through the protective gas port (65).

3. The automatic laser sealing ring welding equipment for thin-walled tube ends according to claim 2, characterized in that, The end plug positioning assembly (2) includes an end plug positioning block (21), a disc spring (22), a thrust bearing (23), a ball bearing (24), a sleeve (25), and a vacuum connector (26). The end plug positioning block (21) is hollow inside. One end of the end plug positioning block (21) is provided with a shoulder, and the other end is inserted into the sleeve (25) and extends out of the sleeve (25). The ball bearing (24) is provided between the end plug positioning block (21) and the sleeve (25). The other end of the end plug positioning block (21) is tumblingly connected to the sleeve (25) through the ball bearing (24). The disc spring (22) and the thrust bearing (23) are connected between one end of the sleeve (25) and the shoulder of the end plug positioning block (21). The shoulder of (21) is elastically and slidably connected to the sleeve (25) through the disc spring (22) and the thrust bearing (23). The other end of the end plug positioning block (21) extends into one end of the vacuum connector (26) and is connected to the inner wall of one end of the vacuum connector (26) through a dynamic seal. One end face of the vacuum connector (26) is connected to the other end of the sleeve (25) through another disc spring (22) and the thrust bearing (23). The vacuum connector (26) is connected to the hollow interior of the end plug positioning block (21). The hollow interior of the end plug positioning block (21) is evacuated through the vacuum connector (26). One end of the shoulder of the end plug positioning block (21) is inserted into the positioning component interface (62).

4. The automatic laser sealing ring welding equipment for thin-walled tube ends according to claim 3, characterized in that, The pushing component (3) includes a cylinder (31) and a connecting tube (32). One end of the connecting tube (32) is connected to the other end of the vacuum connector (26), and the other end of the connecting tube (32) is connected to the cylinder (31). The connecting tube (32) pushes the vacuum connector (26) to move through the cylinder (31).

5. The automatic laser sealing ring welding equipment for thin-walled tube ends according to claim 4, characterized in that, The vacuum connector (26) is connected to a pipe at the end away from the sleeve (25). The pipe is slidably sealed to the vacuum connector (26). The connecting sleeve (32) has a clearance hole for the pipe.

6. The automatic laser sealing ring welding equipment for thin-walled tube ends according to claim 2, characterized in that, An observation component (7) is provided on the side of the welding chamber (6) away from the protective gas interface (65).

7. The automatic laser sealing ring welding equipment for thin-walled tube ends according to claim 6, characterized in that, The observation assembly (7) includes a viewing lens (71), a light channel (72), a coaxial LED light source (73), a CCD camera (74), a semi-reflective beam splitter, and a protective glass (75). The welding chamber (6) has an opening on the side away from the protective gas interface (65), and the protective glass (75) is slidably connected to the opening. A dynamic seal is provided between the protective glass (75) and the outer wall of the welding chamber (6). The light channel (72) is connected to the side of the protective glass (75) away from the welding chamber (6), and the CCD camera (74) is connected to the side of the light channel (72) away from the protective glass (75). Two semi-reflective beam splitters are connected in the light channel (72). The coaxial LED light source (73) and the viewing lens (71) are coaxially connected to the CCD camera (74) through the two semi-reflective beam splitters.

8. The automatic laser sealing ring welding equipment for thin-walled tube ends according to claim 7, characterized in that, The lower end of the CCD camera (74) is connected to an adjustment slide (76), which is used for adjusting the light of the CCD camera (74).

9. The automatic laser sealing ring welding equipment for thin-walled tube ends according to claim 1, characterized in that, The clamping and rotating assembly (4) is a pneumatic rotary collet or a pneumatic rotary chuck.

10. The automatic laser sealing ring welding equipment for thin-walled tube ends according to claim 1, characterized in that, It also includes a water chiller (8), an electrical integrated cabinet (9), a welding machine controller (10), and a laser (11). The laser (11) is connected to the laser welding gun assembly (1) and is used to send a laser beam to the laser welding gun assembly (1). The water chiller (8) is connected to the laser (11) and is used to cool the laser (11). The welding machine controller (10) is connected to the laser (11), the water chiller (8), the laser welding gun assembly (1), the end plug positioning assembly (2), the pushing assembly (3), the clamping and rotating assembly (4), and the positioning sensor (5). The electrical control connection is used to control the laser (11) to emit laser, the water chiller (8) to cool, the end plug positioning component (2) to position, the laser welding gun component (1) to weld, the push component (3) to push, the clamping rotation component (4) to clamp and rotate, and the position sensor (5) to transmit the position signal. The electrical integrated cabinet (9) is used to integrate the electrical pipelines connected to the water chiller (8), the welding machine controller (10), the laser (11), the laser welding gun component (1), the end plug positioning component (2), the push component (3), the clamping rotation component (4), the position sensor (5), and the welding chamber (6).

Images