A multi-axis linkage local vacuum laser welding device and method for longitudinal and annular seams of a cylinder

Abstract

The present invention relates to the technical field of titanium alloy welding. The present invention provides a multi-axis linkage local vacuum laser welding device and method for longitudinal and circumferential seams of a cylinder, wherein the welding device comprises: a rotating support assembly, on which the cylinder to be welded can rotate or remain stationary; a sliding sealing assembly, used to maintain the sealing performance of the local sealing welding area; a vacuum assembly, used to suck gas to form a vacuum welding environment; a multi-axis mechanical arm, used to drive the sliding sealing assembly to approach or move away from the cylinder to be welded; a secondary current acquisition and control system, used to collect secondary current and control the vacuum speed of the vacuum assembly according to the secondary current. The present invention can realize the circumferential seam welding and longitudinal seam welding of the cylinder with one device through the setting of the welding device, thereby reducing the number of devices; through the detection of the secondary current, the vacuum environment state within a certain range above the molten pool can be accurately grasped, thereby timely adjusting the vacuum rate to ensure that the molten pool area is in a better working state.

Description

Technical Field

[0001] The invention relates to the technical field of titanium alloy welding, and in particular to a device and method for welding longitudinal and annular seams of a cylinder using multi-axis linkage and local vacuum laser welding. Background Art

[0002] For titanium alloy thick plate welding, electron beam welding can achieve good joint quality, but electron beam welding needs to be carried out in a vacuum chamber, and large titanium alloy structural parts cannot be laser welded due to size limitations. Narrow gap welding methods are widely used in titanium alloy thick plate welding, but due to the large plate thickness, narrow gap welding requires multi-layer and multi-pass welding, and the welding efficiency is low. At the same time, the deformation control of thick plate welding is difficult, which cannot meet the requirements of efficient welding of large structures.

[0003] In the 1980s, researchers proposed that laser welding under vacuum conditions could improve the utilization rate of laser energy, improve the penetration ability of the incident laser, and significantly increase the weld penetration depth. However, due to the limitation of laser power, the depth-to-width ratio of the weld is much lower than that of electron beam welding. Therefore, electron beam welding is more commonly used for titanium alloy thick plates. In recent years, with the emergence of high-power and high-quality lasers, researchers have found that high-power lasers can also obtain large depth-to-width ratio welds similar to electron beam welding under vacuum, and vacuum laser welding does not require the extremely high vacuum required for electron beam welding. At the same time, laser welding does not have the problem of scattering of electrons by atmospheric molecules, and does not require radiation protection.

[0004] Chinese patent CN201921232451.2 discloses a new type of local vacuum seal and welding device for laser welding, which is suitable for welding large-sized flat workpieces with large thickness; this patent requires the installation of a laser-transmitting glass with the same length as the weld along the weld, which cannot be applied to large structures and is not suitable for welding cylinders.

[0005] Chinese patent CN201611009964.8 discloses a local vacuum laser welding device for the annular seam of a pipeline and a welding method based on the welding device. By installing a fixed vacuum shell at the weld position of the pipeline, local vacuum laser welding of the annular weld is realized. Although the patent can realize local vacuum laser welding, it has the following two disadvantages: First, the patent is only applicable to annular seam welding, and in the production process of the cylinder, it is usually necessary to weld the annular seam and the longitudinal seam. The patent cannot be used for longitudinal seam welding, resulting in the need for multiple production equipment to be used in coordination, and the diameter cylinder needs to be transported between different equipment, the operation steps are complicated, and the production efficiency is low; secondly, when the diameter cylinder is welded, the ovality and straightness of the cylinder are low, and it is difficult for the inner and outer layers of the sealing rubber ring to achieve effective sealing with the cylinder, resulting in its vacuum degree being unable to guarantee the use requirements, affecting the penetration depth of the weld, resulting in poor performance of the welded joint.

[0006] In addition, the researchers found that during vacuum laser welding, even if the vacuum level in the vacuum chamber is maintained to meet the requirements, the weld penetration depth often fluctuates. This situation can easily lead to local incomplete penetration, seriously affecting the mechanical properties of the weld joint and affecting the production yield. Summary of the invention

[0007] The technical problem solved by the present invention is that in the prior art, different welding equipment is required for the cylinder, the annular seam and the longitudinal seam, the number of equipment is large, the welding steps are complicated, and the production efficiency is low. In addition, in the vacuum laser welding process, the vacuum degree often meets the requirements, but the penetration depth does not meet the requirements, which seriously affects the quality of the welded joint.

[0008] The present invention discloses a multi-axis linkage local vacuum laser welding device for longitudinal and annular seams of a cylinder, which is used for welding the annular seams and longitudinal seams of a cylinder to be welded. The welding device comprises:

[0009] A rotating bracket assembly, on which the cylinder to be welded is arranged, and on which the cylinder to be welded can be rotated or fixed;

[0010] A laser welding gun, which is arranged on one side of the cylinder to be welded and is used for welding the cylinder to be welded;

[0011] A sliding sealing assembly, the sliding sealing assembly is used to form a local sealing welding area with the cylinder to be welded, the sliding sealing assembly can slide relative to the cylinder to be welded, and maintain the sealing performance of the local sealing welding area during relative sliding;

[0012] A pressure plate, the pressure plate is fixedly connected to the sliding seal assembly, the pressure plate is arranged on a side of the sliding seal assembly away from the cylinder to be welded, and is used to apply pressure to the sliding seal assembly in a direction toward the cylinder to be welded;

[0013] A smoke and dust protection component, wherein the smoke and dust protection component is arranged between the sliding sealing component and the laser welding gun, and a lens is arranged on the smoke and dust protection component, and the laser generated by the laser welding gun passes through the lens to weld the cylinder to be welded;

[0014] A gas extraction component, which is in communication with the interior of the local sealed welding area and is used to extract gas therein to form a local vacuum welding environment;

[0015] A multi-axis mechanical arm, the multi-axis mechanical arm is fixedly connected to the pressure plate, and is used to drive the sliding seal assembly to approach or move away from the cylinder to be welded through the pressure plate, and can apply pressure to the sliding seal assembly in the direction of the cylinder to be welded through the pressure plate, and can also drive the sliding seal assembly to move along the axial direction of the cylinder to be welded or keep the sliding seal assembly fixed;

[0016] A secondary current collection and control system comprises at least a secondary current collecting electrode, which is arranged above the welding pool in the local sealed welding area and is used to collect the potential difference between the secondary current collecting electrode and the cylinder to be welded. The secondary current collection and control system obtains the secondary current according to the potential difference, and controls the exhaust speed of the exhaust component according to the comparison result between the secondary current and a preset threshold value.

[0017] On the one hand, it is possible to achieve local vacuum sealing welding of the circumferential seams and longitudinal seams on the cylinder to be welded, which can be achieved with only one device, reducing the number of equipment, reducing space occupancy, and saving the steps of transferring and installing the cylinder to be welded between different devices, significantly improving production efficiency and reducing production costs; on the other hand, the sliding sealing component fits tightly with the outer wall of the cylinder to be welded under pressure, and the tightness of the fit can be ensured even when the ovality and straightness of the cylinder are not good, thereby ensuring the sealing effect and vacuum stability of the local sealing welding area; in addition, the vacuum speed of the vacuum assembly is adjusted through the detection of the secondary current, so that the vacuum environment above the molten pool in the local sealing welding area can be more accurately controlled, thereby ensuring the smooth progress of the welding process and the welding penetration.

[0018] Furthermore, the rotating bracket assembly includes a supporting part, a rotating part and a clamping part. The rotating part is arranged on the supporting part, and the rotating part can be rotated or locked relative to the supporting part. The clamping part is arranged on the rotating part. There are multiple clamping parts, and the multiple clamping parts are used to cooperate in clamping the cylinder to be welded.

[0019] By arranging that the rotating part can rotate or lock relative to the supporting part, the cylinder to be welded can be rotated or fixed on the rotating bracket assembly, thereby cooperating with the multi-axis robot arm to weld the circumferential seam and longitudinal seam of the cylinder to be welded.

[0020] Furthermore, the clamping portion can move synchronously along the radial direction of the cylinder to be welded.

[0021] Through the above arrangement, the clamping part can synchronously move inwards toward the center of the rotating part or synchronously expand outwards away from the center, so that the diameter of the clampable part can be adjusted, so that it can be used for welding cylinders with different diameters to be welded.

[0022] Furthermore, a first connecting portion and a second through hole are provided on the pressure plate, the multi-axis robot arm is fixedly connected to the first connecting portion, and the smoke and dust protection component is fixedly provided in the second through hole.

[0023] Through the above arrangement, the multi-axis robot arm can drive the pressure plate, the smoke protection component, and the sliding sealing component to move synchronously when moving, thereby realizing mobile welding of the longitudinal seam.

[0024] Furthermore, the sliding sealing assembly includes a sealing plate, a first through hole is arranged at the center of the sealing plate, the first through hole is sealed and assembled with the smoke protection assembly, the laser emitted by the laser welding gun can pass through the first through hole to weld the cylinder to be welded, and an elastic sealing assembly is arranged on the side of the sealing plate away from the laser welding gun, the elastic sealing assembly protrudes from the sealing plate and extends toward the direction of the cylinder to be welded, and the sealing plate and the elastic sealing assembly are both arc-shaped surfaces on one side close to the cylinder to be welded.

[0025] Through the above-mentioned arrangement, when welding the cylinder to be welded, whether it is circumferential seam welding or longitudinal seam welding, the sliding sealing assembly can maintain the sealing effect of the local sealed welding area when it slides relative to the cylinder to be welded, so as to maintain the vacuum environment in the local sealed welding area, thereby ensuring the smooth progress of the laser welding process.

[0026] Furthermore, a first accommodating groove and a second accommodating groove are provided on the side of the sealing plate away from the laser welding gun, the first accommodating groove and the second accommodating groove are both provided in a closed ring shape, and the center of the first accommodating groove and the center of the second accommodating groove coincide with the center of the sealing plate, the elastic sealing assembly includes a first sealing ring and a second sealing ring, the first sealing ring is provided in the first accommodating groove, and the first sealing ring is interference fit with the first accommodating groove, the second sealing ring is provided in the second accommodating groove, and the second sealing ring is interference fit with the second accommodating groove.

[0027] The setting of two layers of sealing rings can significantly improve the sealing effect of the local sealing welding area. The interference fit setting ensures the setting stability of the first sealing ring and the second sealing ring, avoids falling off during relative sliding with the cylinder to be welded, ensures the sealing effect of the local sealing welding area, and enables local vacuum laser welding to be carried out stably.

[0028] Furthermore, the vacuum assembly includes a vacuum pipe and a vacuum pump, one end of the vacuum pipe is connected to the inner cavity of the local sealed welding area, and the other end is connected to the vacuum pump.

[0029] Before and during welding, the vacuum pump draws gas from the inner cavity of the local sealed welding area in real time through the vacuum pipe to ensure the stability of its vacuum degree, so that the local vacuum laser welding can proceed smoothly.

[0030] Furthermore, the secondary current acquisition and control system also includes a load resistor, an electrical signal amplification module, an electrical signal analysis module, and a comparison control module. The load resistor is connected to the secondary current collecting electrode to form a load loop for real-time collection of secondary current signals. The electrical signal amplification module is respectively communicated with the load loop and the electrical signal analysis module for transmission and amplification of secondary current signals. The electrical signal analysis module is used to receive the secondary current signal transmitted by the electrical signal amplification module and analyze to obtain the secondary current value. The comparison control module is used to compare the secondary current value obtained by the electrical signal analysis module with a preset threshold value and adjust the exhaust speed of the exhaust assembly according to the comparison result.

[0031] By adjusting the exhaust speed of the exhaust assembly through the detection of the secondary current, the vacuum environment above the molten pool in the local sealed welding area can be controlled more accurately, thereby ensuring the smooth progress of the welding process.

[0032] The present invention also discloses a method for multi-axis linkage local vacuum laser welding of longitudinal and annular seams of a cylinder, using the welding device as described above, and the welding method comprises:

[0033] Step S1: Preparation before welding: Process the groove of the cylinder to be welded as required, and process its surface to meet the welding requirements, and then assemble it on the welding device;

[0034] Step S2: evacuate the welding area to make the vacuum degree meet the welding requirements;

[0035] Step S3: After the vacuum degree meets the requirement, the laser welding gun is started to perform welding, and the movement of corresponding components is controlled to perform laser welding according to the shape of the weld;

[0036] Step S4: synchronously detecting the secondary current at a certain position above the molten pool during the welding process, and controlling the exhaust speed of the exhaust component according to the relationship between the secondary current and a preset threshold value;

[0037] Step S5: After welding is completed, the laser welding gun is turned off, and after a first preset time, the exhaust assembly is turned off.

[0038] The advantages of the welding method and the welding device described above over the prior art are the same and will not be described in detail here.

[0039] Further, in step S4, controlling the air extraction speed of the air extraction component according to the relationship between the secondary current and the preset threshold value includes:

[0040] The detected secondary current is compared with a preset threshold value. When it is detected that the secondary current is greater than or equal to the preset threshold value, the suction speed of the suction component is increased. When it is detected that the secondary current is less than the preset threshold value, the suction speed of the suction component is maintained.

[0041] When it is detected that the secondary current is greater than or equal to the preset threshold, it means that under the influence of the plasma cloud and smoke above the molten pool, the vacuum degree near the molten pool is difficult to meet the requirements. In this case, the welding penetration depth is difficult to meet the requirements. At this time, increasing the exhaust speed of the exhaust assembly can increase the speed of extracting the plasma cloud and smoke, thereby reducing their impact on the laser beam, ensuring the welding penetration depth, and thus obtaining the required welding quality.

[0042] Compared with the prior art, the multi-axis linkage local vacuum laser welding device and method for longitudinal and annular seams of a cylinder described in the present invention have the following advantages:

[0043] 1. The present invention can realize the circumferential seam welding and longitudinal seam welding of the cylinder body by setting the welding device, thereby reducing the number of equipment, reducing space occupation, improving production efficiency and reducing production costs;

[0044] 2. Through the setting of local sealing components, local laser welding on the cylinder is realized, which provides a strong guarantee for vacuum laser welding of large cylinders;

[0045] 3. Through the detection of secondary current, the vacuum environment state within a certain range above the molten pool can be accurately grasped, so as to adjust the exhaust rate in time to ensure that the molten pool area is in a better working state, ensure the stability of the weld penetration, and improve the quality of the weld joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a structural schematic diagram of a multi-axis linkage local vacuum laser welding device for longitudinal and annular seams of a cylinder according to an embodiment of the present invention;

[0047] Figure 2 It is a structural schematic diagram of the rotating bracket assembly according to an embodiment of the present invention;

[0048] Figure 3 It is a schematic structural diagram of a laser welding gun, a sliding sealing assembly, a smoke protection assembly and a pressure plate according to an embodiment of the present invention;

[0049] Figure 4 This is a schematic structural diagram of a sliding seal assembly according to an embodiment of the present invention;

[0050] Figure 5 It is a structural schematic diagram of the sliding seal assembly according to an embodiment of the present invention from another angle;

[0051] Figure 6 This is a schematic diagram of the structure of the sliding sealing assembly according to an embodiment of the present invention after the elastic sealing assembly is removed;

[0052] Figure 7 This is a schematic structural diagram of a sealing assembly according to an embodiment of the present invention;

[0053] Figure 8 It is a structural schematic diagram of a load circuit for secondary current detection according to an embodiment of the present invention.

[0054] Description of reference numerals:

[0055] 100, laser welding gun; 200, smoke protection assembly; 210, pressure cover; 220, lens; 300, pressure plate; 310, first connecting part; 400, sliding sealing assembly; 410, first through hole; 420, mounting part; 430, exhaust pipe; 440, elastic sealing assembly; 441, first sealing ring; 442, second sealing ring; 450, first accommodating groove; 460, second accommodating groove; 500, cylinder to be welded; 600, rotating bracket assembly; 610, supporting part; 620, rotating part; 630, clamping part; 700, multi-axis robotic arm. DETAILED DESCRIPTION

[0056] To make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0057] The following describes in detail a device and method for multi-axis linkage local vacuum laser welding of longitudinal and annular seams of a cylinder according to an embodiment of the present invention in conjunction with the accompanying drawings.

[0058] Example 1

[0059] This embodiment provides a multi-axis linkage local vacuum laser welding device for longitudinal and annular seams of a cylinder. Figure 1-Figure 8 As shown, the welding device is used for welding the annular seam and the longitudinal seam of the cylinder 500 to be welded, and the welding device includes:

[0060] A rotating bracket assembly 600, on which the cylinder 500 to be welded is arranged, and on which the cylinder 500 to be welded can be rotated or fixed;

[0061] A laser welding gun 100, which is disposed on one side of the cylinder 500 to be welded and is used for welding the cylinder 500 to be welded;

[0062] A sliding seal assembly 400, wherein the sliding seal assembly 400 is used to form a local sealing welding area with the cylinder 500 to be welded, and the sliding seal assembly 400 can slide relative to the cylinder 500 to be welded, and maintain the sealing performance of the local sealing welding area during the relative sliding;

[0063] A pressure plate 300, the pressure plate 300 is fixedly connected to the sliding seal assembly 400, the pressure plate 300 is arranged on a side of the sliding seal assembly 400 away from the cylinder 500 to be welded, and is used to apply pressure to the sliding seal assembly 400 in a direction toward the cylinder 500 to be welded;

[0064] A smoke protection component 200, wherein the smoke protection component 200 is disposed between the sliding sealing component 400 and the laser welding gun 100, and a lens 220 is disposed on the smoke protection component 200, and the laser generated by the laser welding gun 100 passes through the lens 220 to weld the cylinder 500 to be welded;

[0065] A gas extraction component, which is in communication with the interior of the local sealed welding area and is used to extract gas therein to form a local vacuum welding environment;

[0066] A multi-axis mechanical arm 700, the multi-axis mechanical arm 700 is fixedly connected to the pressure plate 300, and is used to drive the sliding seal assembly 400 to approach or move away from the cylinder 500 to be welded through the pressure plate 300, and can apply pressure to the sliding seal assembly 400 in the direction of the cylinder 500 to be welded through the pressure plate 300, and can also drive the sliding seal assembly 400 to move along the axial direction of the cylinder 500 to be welded or keep the sliding seal assembly 400 fixed;

[0067] A secondary current collection and control system (not shown in the drawings) comprises at least a secondary current collecting electrode, which is arranged above the welding pool in the local sealed welding area and is used to collect the potential difference between the secondary current collecting electrode and the cylinder 500 to be welded. The secondary current collection and control system obtains the secondary current according to the potential difference and controls the exhaust speed of the exhaust assembly according to the detected secondary current.

[0068] The researchers of this application found that the vacuum detection in the existing vacuum laser welding process is to measure the entire vacuum chamber using a vacuum gauge or a vacuum gauge, which detects the vacuum degree of the entire vacuum chamber. During the vacuum laser welding process, a large amount of metal vapor and smoke will be generated at the part where the base material contacts the laser. The metal vapor absorbs the laser beam and is ionized into a plasma cloud, so that the vacuum degree of the part above the molten pool in the vacuum chamber is much worse than the vacuum degree of other positions. That is to say, when the vacuum detection device detects that the vacuum degree is qualified, it reflects that the overall vacuum degree in the vacuum chamber is qualified, but the plasma cloud above the molten pool will cause the vacuum degree of the local area near the molten pool to be unqualified. The plasma cloud will consume the energy of the laser beam to a certain extent, causing the penetration depth during laser welding to fluctuate. In severe cases, local incomplete penetration will occur, resulting in unqualified joint quality. This problem has been plaguing the field of vacuum laser welding in recent years, but the current vacuum detection equipment cannot accurately measure the vacuum degree near the weld molten pool, and the stability of the molten pool during the welding process is more directly affected by the vacuum degree above and around it. At present, there is no method and device that can directly detect the vacuum degree near the molten pool, resulting in the inability to solve the above technical problems.In the present embodiment, through the above arrangement, on the one hand, local vacuum sealing welding of the circumferential seam and the longitudinal seam on the cylinder 500 to be welded can be achieved. When the circumferential seam welding is performed, after the laser welding gun 100 and the sliding sealing assembly 400 are focused and adjusted with the area to be welded, they remain fixed during welding, and the cylinder 500 to be welded rotates relative to the sliding sealing assembly 400 to achieve local vacuum sealing welding of the circumferential seam; when the longitudinal seam welding is performed, after the laser welding gun 100 and the sliding sealing assembly 400 are focused and adjusted with the area to be welded, the cylinder 500 to be welded remains fixed, and the multi-axis robot arm 700 drives the sliding sealing assembly 400 and the laser welding gun 100 to move along the axial direction of the cylinder 500 to be welded to achieve local vacuum sealing welding of the longitudinal seam. Only one device is required to achieve the circumferential seam welding and the longitudinal seam welding of the cylinder 500 to be welded, which reduces the number of equipment, reduces the space occupancy, and also saves energy. The steps of transferring and installing the cylinder 500 to be welded between different equipment are saved, which significantly improves production efficiency and reduces production costs; on the other hand, due to the setting of the pressure plate 300 and the sliding sealing assembly 400, the sliding sealing assembly 400 is tightly fitted with the outer wall of the cylinder 500 to be welded under pressure, and the tightness of the fit can be guaranteed even when the cylinder ovality and straightness are not good, thereby ensuring the sealing effect and vacuum stability of the local sealing welding area; in addition, according to the plasma fluctuation characteristics, the electron movement speed is relatively fast during laser welding, which can form a potential difference relative to the direction of the laser incident axis. After collecting the potential difference, the environmental state of the local sealing welding area can be accurately analyzed. Therefore, the exhaust speed of the exhaust assembly can be adjusted by detecting the secondary current, so as to more accurately control the vacuum environment above the molten pool in the local sealing welding area, thereby ensuring the smooth progress of the welding process. It should be noted that in the present application, the laser welding gun 100 is relatively fixedly arranged with the sliding sealing assembly 400, the pressure plate 300, and the smoke protection assembly 200. In some optional embodiments, the laser welding gun 100 is fixedly disposed on the multi-axis robot arm 700 .

[0069] As one of the optional embodiments, Figure 2As shown, the rotating support assembly 600 includes a support portion 610, a rotating portion 620 and a clamping portion 630. The rotating portion 620 is arranged on the supporting portion 610, and the rotating portion 620 can rotate or lock relative to the supporting portion 610. The clamping portion 630 is arranged on the rotating portion 620. There are multiple clamping portions 630, and the multiple clamping portions 630 are used to cooperate and clamp the cylinder 500 to be welded. Through the setting that the rotating portion 620 can rotate or lock relative to the supporting portion 610, the rotation or fixation of the cylinder 500 to be welded on the rotating support assembly 600 can be achieved, so as to cooperate with the multi-axis robot arm 700 to weld the circumferential seam and longitudinal seam of the cylinder 500 to be welded. The clamping portion 630 can fix and clamp the cylinder 500 to be welded on the rotating portion 620, so that the cylinder 500 to be welded can rotate or lock with the rotating portion 620. It should be understood that the rotating or locking connection structure between the rotating part 620 and the supporting part 610 can refer to the prior art and will not be limited here. It should be noted that before the cylinder 500 to be welded is fixedly clamped on the rotating part 620, it is necessary to spot weld the cylinder 500 to be welded so as to set it on the rotating part 620. A roller frame (not shown in the drawings) is also provided on the lower side of the cylinder 500 to be welded. The roller frame is used to support the cylinder 500 to be welded to avoid deformation. As another optional embodiment, the rotating bracket assembly 600 includes two sets of supporting parts 610, rotating parts 620 and clamping parts 630. The two sets of supporting parts 610, rotating parts 620 and clamping parts 630 are relatively arranged at the two ends of the axial direction of the two cylinders 500 to be welded. Each set of supporting parts 610, rotating parts 620 and clamping parts 630 is used to support and set one cylinder 500 to be welded. Preferably, the two support portions 610 can be relatively close to or far away from each other along the axial direction of the to-be-welded cylinder 500. This arrangement makes the distance between the two support portions 610 adjustable, which, on the one hand, facilitates the installation support of the to-be-welded cylinder 500, and on the other hand, enables the welding device to be used for welding cylinders 500 of different lengths.

[0070] As one of the preferred embodiments, the clamping part 630 can synchronously move along the radial direction of the cylinder 500 to be welded. Through the above arrangement, the clamping part 630 can synchronously move inward toward the center of the rotating part 620 or synchronously expand outward in a direction away from the center, so that the diameter of the clampable part can be adjusted, so that it can be used for welding cylinders 500 to be welded with different diameters. The driving structure of the clamping part 630 synchronously moving along the radial direction of the cylinder 500 to be welded can refer to the prior art and will not be limited here.

[0071] As an embodiment of the present invention, Figure 3As shown, a first connection portion 310 and a second through hole (not shown in the drawings) are provided on the pressure plate 300, the multi-axis robot arm 700 is fixedly connected to the first connection portion 310, and the smoke protection assembly 200 is fixedly provided in the second through hole. Through the above arrangement, the multi-axis robot arm 700 can drive the pressure plate 300, the smoke protection assembly 200, and the sliding sealing assembly 400 to move synchronously when moving, thereby realizing the mobile welding of the longitudinal seam. Among them, the smoke protection assembly 200 includes a lens 220, a pressure cover 210, a smoke protection chamber and an air block (not shown in the drawings). The specific structure and positional relationship of each component can refer to the prior art and will not be repeated here. During the laser welding process, especially the welding process of titanium alloy, a large amount of smoke will be generated. If this smoke enters the smoke protection chamber, it will seriously contaminate the lens 220, reduce its light transmittance, and cause poor laser welding effect and efficiency. The setting of the gas resistance greatly reduces the amount of smoke entering the smoke protection chamber, avoids the contamination of the lens 220, and effectively ensures the efficiency and quality of laser welding.

[0072] As an embodiment of the present invention, Figure 4 , Figure 5 As shown, the sliding seal assembly 400 includes a sealing plate, a first through hole 410 is provided at the center of the sealing plate, the first through hole 410 is sealed and assembled with the smoke protection assembly 200, the laser emitted by the laser welding gun 100 can pass through the first through hole 410 to weld the cylinder 500 to be welded, and an elastic sealing assembly 440 is provided on the side of the sealing plate away from the laser welding gun 100, the elastic sealing assembly 440 protrudes from the sealing plate and extends toward the cylinder 500 to be welded, and the sealing plate and the elastic sealing assembly 440 are both arc-shaped surfaces close to the cylinder 500 to be welded. Preferably, the sealing plate and the elastic sealing assembly 440 are both arc-shaped surfaces close to the cylinder 500 to be welded, which match the outer diameter of the cylinder 500 to be welded. It should be noted that the elastic sealing assembly 440 is a low-hardness and high-temperature resistant sealing material, which can contact with the weld during welding without being burned, and is easily deformed under pressure to maintain the sealing effect of the local sealing welding area. Through the above-mentioned arrangement, when welding the cylinder 500 to be welded, whether it is circumferential seam welding or longitudinal seam welding, the sliding sealing assembly 400 can maintain the sealing effect of the local sealed welding area when sliding relative to the cylinder 500 to be welded, so as to maintain the vacuum environment in the local sealed welding area, thereby ensuring the smooth progress of the laser welding process.

[0073] As one of the preferred embodiments, Figure 6 , Figure 7As shown, a first accommodating groove 450 and a second accommodating groove 460 are provided on the side of the sealing plate away from the laser welding gun 100, the first accommodating groove 450 and the second accommodating groove 460 are both provided in a closed ring shape, and the center of the first accommodating groove 450 and the center of the second accommodating groove 460 coincide with the center of the sealing plate, the elastic sealing assembly 440 includes a first sealing ring 441 and a second sealing ring 442, the first sealing ring 441 is provided in the first accommodating groove 450, and the first sealing ring 441 and the first accommodating groove 450 are interference fit, the second sealing ring 442 is provided in the second accommodating groove 460, and the second sealing ring 442 and the second accommodating groove 460 are interference fit.

[0074] The setting of two layers of sealing rings can significantly improve the sealing effect of the local sealing welding area. The interference fit setting ensures the setting stability of the first sealing ring 441 and the second sealing ring 442, avoids falling off during relative sliding with the cylinder 500 to be welded, ensures the sealing effect of the local sealing welding area, and enables local vacuum laser welding to be carried out stably.

[0075] The exhaust assembly includes an exhaust pipe 430 and an exhaust pump (not shown in the drawings). One end of the exhaust pipe 430 is connected to the inner cavity of the local sealed welding area, and the other end is connected to the exhaust pump. Before and during welding, the exhaust pump extracts the gas in the inner cavity of the local sealed welding area through the exhaust pipe 430 in real time to ensure the stability of its vacuum degree, so that the local vacuum laser welding can be carried out smoothly.

[0076] Optionally, the multi-axis robot 700 is a six-axis robot, which can drive the sliding sealing assembly 400, the pressure plate 300, and the smoke protection assembly 200 to change their positions in multiple directions and angles, so as to keep the above-mentioned components stationary during circumferential seam welding, and can also drive the above-mentioned components to perform large-stroke displacement during longitudinal seam welding, thereby ensuring the flexibility of switching between the circumferential seam and longitudinal seam welding modes of the cylinder 500 to be welded.

[0077] In some optional embodiments, the sliding seal assembly 400 further includes a mounting portion 420, and the mounting portion 420 is used to mount a vacuum gauge (not shown in the drawings), and the vacuum gauge is used to detect the vacuum degree of the cavity in the local sealing welding area. The vacuum gauge is only used to detect the overall average vacuum degree of the cavity in the local sealing welding area, and cannot accurately obtain the vacuum condition within a certain distance above the molten pool.

[0078] As an embodiment of the present invention, Figure 8As shown, the secondary current acquisition control system also includes a load resistor and an oscilloscope device. The load resistor is connected to the secondary current collector to form a load loop. The potential difference can form a voltage drop on the load resistor. The oscilloscope device is used to detect the voltage drop, thereby obtaining the secondary current, and amplifying the secondary current to display it as a current waveform. It should be understood that the secondary current can be obtained according to I=U / R, where I is the secondary current, U is the two ends of the load resistor, and R is the resistance value of the load resistor. The corresponding secondary current value can be obtained through the above calculation. It should be noted that due to the extremely small potential difference, the detected secondary current value is also extremely small, which can be amplified and displayed by the oscilloscope device. Through the above settings, the vacuum condition within a certain range above the molten pool can be detected in a timely and accurate manner. On this basis, it is helpful to adjust the corresponding exhaust scheme according to the vacuum condition so that the vacuum laser welding can obtain a satisfactory melting depth. The oscilloscope device is an oscilloscope or other device that can detect voltage or current signals and display them as waveforms, which is no longer limited here.

[0079] In a specific implementation, through the previous vacuum laser welding test, the secondary current and the weld penetration parameter are correlated and analyzed according to the support vector machine to obtain the characterization relationship between the secondary current and the penetration. According to the above characterization relationship, the secondary current corresponding to the required penetration of the thickness of the cylinder 500 to be welded can be selected as the preset threshold. During the welding process, when it is detected that the secondary current is greater than or equal to the preset threshold, the exhaust speed of the exhaust component is increased. When it is detected that the secondary current is less than the preset threshold, the exhaust speed of the exhaust component is maintained. It should be noted that the characterization relationship can be a correlation relationship diagram or a correlation comparison table.

[0080] Furthermore, in the vacuum laser welding test, the semiconductor laser backlight source, narrowband filtering, and image processing technology can be combined to filter and amplify the collected electrical signal through an op amp, compare the cluttered signal through a comparator, and perform signal shaping processing through a shaper. The main frequency of the signal and the main frequency area energy ratio are selected as characteristic parameters to characterize the signal, remove the welding interference signal, and extract the specific current signal output value according to the characteristic parameters, so as to obtain a more accurate secondary current value. Among them, the narrowband filtering, image processing technology, etc. are all existing technologies and are not limited here.

[0081] As one of the preferred embodiments, the welding device also includes a back protection assembly, which is arranged opposite to the sliding sealing assembly 400 on the inner wall of the cylinder 500 to be welded, and the back protection assembly is tightly fitted to the inner wall of the cylinder 500 to be welded. The cavity of the back protection assembly is filled with inert gas or maintained in a vacuum state to protect the back of the laser welding part. The back protection assembly can be fixed during circumferential seam welding, and can also move synchronously with the sliding sealing assembly 400 along the axial direction of the cylinder 500 to be welded during longitudinal seam welding. Optionally, the back protection component is a frame structure, and the contact part with the cylinder 500 to be welded is also made of low-hardness and high-temperature resistant sealing material to ensure its sealing performance. A guide member (not shown in the drawings) extending along the axial direction of the cylinder 500 to be welded is provided on the rotating part 620, and the back protection component is arranged on the guide member, and the guide member can keep the back protection component stationary or drive it to move along the axial direction of the cylinder 500 to be welded, and in this process, the guide member can also apply pressure to the back protection component toward the inner wall of the cylinder 500 to be welded. Through the above arrangement, the internal weld of the cylinder 500 to be welded can be protected during the welding of the circumferential seam and the longitudinal seam, and oxidation can be avoided during the welding process, thereby ensuring the welding quality.

[0082] It should be noted that the welding device provided in this embodiment can be used for welding metal structures such as titanium alloy, steel, and aluminum alloy.

[0083] Example 2

[0084] This embodiment provides a method for multi-axis linkage local vacuum laser welding of longitudinal and annular seams of a cylinder, using the welding device described in Embodiment 1. The welding method includes:

[0085] Step S1: Preparation before welding: Process the groove of the cylinder to be welded as required, and process its surface to meet the welding requirements, and then assemble it on the welding device;

[0086] Step S2: evacuate the welding area to make the vacuum degree meet the welding requirements;

[0087] Step S3: After the vacuum degree meets the requirement, the laser welding gun is started to perform welding, and the movement of corresponding components is controlled to perform laser welding according to the shape of the weld;

[0088] Step S4: synchronously detecting the secondary current at a certain position above the molten pool during the welding process, and controlling the exhaust speed of the exhaust component according to the relationship between the secondary current and a preset threshold value;

[0089] Step S5: After welding is completed, the laser welding gun is turned off, and after a first preset time, the exhaust assembly is turned off.

[0090] Through the above-mentioned arrangement, on the one hand, local vacuum sealing welding of the circumferential seam and the longitudinal seam on the cylinder 500 to be welded can be achieved with only one device, which reduces the number of equipment, reduces space occupancy, and saves the steps of transferring and installing the cylinder 500 to be welded between different devices, significantly improving production efficiency and reducing production costs; on the other hand, due to the arrangement of the pressure plate 300 and the sliding sealing assembly 400, the sliding sealing assembly 400 fits tightly with the outer wall of the cylinder 500 to be welded under pressure, and the tightness of the fit can be ensured even when the ovality and straightness of the cylinder are not good, thereby ensuring the sealing effect of the local sealing welding area and the stability of the vacuum degree; in addition, by adjusting the exhaust speed of the exhaust assembly through the detection of the secondary current, the vacuum environment above the molten pool in the local sealing welding area can be more accurately controlled, thereby ensuring the smooth progress of the welding process and the welding penetration.

[0091] Wherein, step S1 comprises:

[0092] Step S11: processing an I-shaped groove on the cylinder to be welded;

[0093] Step S12: Mechanically grinding the groove surface and the parent material within a certain range of the edge;

[0094] Step S13: using acetone and alcohol solvent to clean and remove oil stains;

[0095] Step S14: Assemble the cylinder to be welded onto the rotating bracket assembly.

[0096] Through the above arrangement, the cleanliness of the area to be welded is ensured, which is helpful to obtain a qualified weld joint in subsequent welding. The certain range in step S12 refers to the range of 30 mm from the groove edge.

[0097] As one embodiment, step S2 includes:

[0098] Step S21: fitting and sealing the sliding sealing assembly to the area to be welded;

[0099] Step S22: Start the vacuum assembly to evacuate the local sealed welding area until the welding requirements are met.

[0100] After assembly and during welding, the sliding seal assembly 400 always maintains a certain pressure between it and the cylinder 500 to be welded, so that the elastic seal assembly has a certain amount of downward deformation, thereby achieving a good fit and seal between the sliding seal assembly 400 and the cylinder 500 to be welded.

[0101] Optionally, step S2 further includes:

[0102] Step S23: fitting and sealing the back protection component to the inner wall of the area to be welded;

[0103] Step S24: evacuate the space inside the back protection component, or fill the internal space with inert gas.

[0104] The provision of the back protection assembly can effectively protect the back area of ​​the welding position, prevent it from being oxidized during the welding process, and ensure the quality of the joint.

[0105] As an embodiment of the present invention, step S3 includes:

[0106] Step S31: Start the laser welding gun, perform step S32 for circumferential seam welding, and perform step S33 for longitudinal seam welding;

[0107] Step S32: The laser welding gun, the sliding sealing assembly, the pressure plate, and the smoke protection assembly remain stationary, and the welding cylinder is rotated for welding;

[0108] Step S33: the cylinder to be welded remains stationary, and the laser welding gun, the sliding sealing assembly, the pressure plate, and the smoke protection assembly are synchronously moved along the axial direction of the cylinder to be welded to perform welding;

[0109] Step S34: while steps S31, S32 and S33 are being performed, a multi-axis robot arm is used to apply pressure to the pressure plate in the direction of the cylinder to be welded.

[0110] Through the above arrangement, one device can be used to weld the longitudinal seam and the circumferential seam, saving the procedure of transporting the cylinder to be welded and the steps of pre-welding preparation, reducing equipment costs and improving production efficiency. It should be understood that during the welding process, the smoke protection component prevents metal vapor from contaminating the lens through the air curtain, thereby ensuring the light transmittance of the lens during the welding process.

[0111] In step S4, the certain position above the molten pool refers to a position 5 to 15 cm above the molten pool, preferably 10 cm.

[0112] The above arrangement can accurately detect the vacuum environment state in a certain area above the molten pool, thereby facilitating more accurate control of the environment state of the welding area.

[0113] In step S4, controlling the air extraction speed of the air extraction component according to the relationship between the secondary current and the preset threshold value includes:

[0114] The detected secondary current is compared with a preset threshold value. When it is detected that the secondary current is greater than or equal to the preset threshold value, the suction speed of the suction component is increased. When it is detected that the secondary current is less than the preset threshold value, the suction speed of the suction component is maintained.

[0115] When it is detected that the secondary current is greater than or equal to the preset threshold, it means that under the influence of the plasma cloud and smoke above the molten pool, the vacuum degree near the molten pool is difficult to meet the requirements. In this case, the welding penetration depth is difficult to meet the requirements. At this time, increasing the exhaust speed of the exhaust assembly can increase the speed of extracting the plasma cloud and smoke, thereby reducing their impact on the laser beam, ensuring the welding penetration depth, and thus obtaining the required welding quality.

[0116] In step S5, the first preset time is 30-60 seconds, preferably 45 seconds.

[0117] It should be noted that the preset threshold value will vary accordingly depending on the different materials and thicknesses of the cylinder to be welded, and it is necessary to determine the preset threshold value of the secondary current corresponding to the parent material under the corresponding parameters through vacuum laser welding tests.

[0118] Example 3

[0119] This embodiment adopts the welding device provided in Embodiment 1 and the welding method provided in Embodiment 2 to weld a ship Ti80 titanium alloy cylinder, the thickness of the base material is 40 mm, and the service environment of the base material has high requirements on impact toughness.

[0120] According to the previous vacuum laser welding test data, the preset threshold of the secondary current during vacuum laser welding of 40mm thick Ti80 titanium alloy was determined. During the welding process, the secondary current at 10cm above the molten pool was detected to adjust the exhaust speed of the exhaust assembly. When the secondary current was greater than or equal to the preset threshold, the exhaust rate was increased. When the secondary current was less than the preset threshold, the current exhaust rate was maintained. The penetration depth was stable, and no incomplete penetration was found in the post-weld inspection. There was no nail tip defect in the welded joint, and the X-ray flaw detection met the requirements of NB 47013-2015 Grade I. In addition, the Ti80 titanium alloy joint obtained by the above welding method has a penetration depth of about 3 times that of ordinary laser welding, and has good mechanical properties, with a tensile strength coefficient of more than 0.95 and a higher impact absorption energy than the parent material, as shown in Table 1.

[0121] Table 1 Comparison of performance of local vacuum laser welded Ti80 titanium alloy joint and parent material

[0122]

[0123] In addition to the welding thickness and performance being better than those of normal pressure laser welding joints, the local vacuum laser welding device and method provided in this application can achieve efficient laser welding of large cylindrical structures, and can significantly improve production efficiency, ensuring the stability of the melting depth during vacuum laser welding, and has important significance and application prospects in the field of ships and deep-sea equipment.

[0124] It should be noted that all the terms used in the present invention for directional and positional indications, such as: "up", "down", "left", "right", "front", "back", "vertical", "horizontal", "inside", "outside", "top", "low", "tail end", "head end", "center", etc., are only used to explain the relative position relationship, connection status, etc. between the components in a certain state, and are only for the convenience of describing the present invention, rather than requiring the present invention to be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the descriptions of "first", "second", etc. in the present invention are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which both A and B are satisfied.

[0125] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0126] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A multi-axis linkage local vacuum laser welding device for longitudinal and annular seams of a cylinder, used for welding annular seams and longitudinal seams of a cylinder (500) to be welded, characterized in that: The welding device comprises: A rotating support assembly (600), the cylinder body (500) to be welded being arranged on the rotating support assembly (600), and the cylinder body (500) to be welded being able to rotate or remain stationary on the rotating support assembly (600); A laser welding gun (100), the laser welding gun (100) being arranged on one side of the cylinder (500) to be welded and being used for welding the cylinder (500) to be welded; A sliding sealing assembly (400), the sliding sealing assembly (400) being used to form a local sealing welding area with a cylinder (500) to be welded, the sliding sealing assembly (400) being able to slide relative to the cylinder (500) to be welded, and maintaining the sealing performance of the local sealing welding area during the relative sliding; a pressure plate (300), the pressure plate (300) being fixedly connected to the sliding seal assembly (400), the pressure plate (300) being arranged on a side of the sliding seal assembly (400) away from the cylinder (500) to be welded, and being used to apply pressure to the sliding seal assembly (400) in a direction towards the cylinder (500) to be welded; A smoke protection component (200), the smoke protection component (200) being arranged between the sliding sealing component (400) and the laser welding gun (100), a lens (220) being arranged on the smoke protection component (200), and laser light generated by the laser welding gun (100) passing through the lens (220) to weld the cylinder (500) to be welded; A gas extraction component, which is in communication with the interior of the local sealed welding area and is used to extract gas therein to form a local vacuum welding environment; a multi-axis mechanical arm (700), the multi-axis mechanical arm (700) being fixedly connected to the pressure plate (300), and being used for driving the sliding seal assembly (400) to approach or move away from the cylinder (500) to be welded via the pressure plate (300), and being able to apply pressure in the direction of the cylinder (500) to the sliding seal assembly (400) via the pressure plate (300), and being able to drive the sliding seal assembly (400) to move along the axial direction of the cylinder (500) to be welded, or to keep the sliding seal assembly (400) fixed; A secondary current collection and control system comprises at least a secondary current collecting electrode, the secondary current collecting electrode being arranged above a welding molten pool in a local sealed welding area and being used to collect the potential difference between the secondary current collecting electrode and a cylinder (500) to be welded, the secondary current collection and control system acquiring a secondary current according to the potential difference, and controlling a suction speed of the suction component according to a comparison result between the secondary current and a preset threshold.

2. The multi-axis linkage local vacuum laser welding device for longitudinal and annular seams of a cylinder as claimed in claim 1, characterized in that: The rotating bracket assembly (600) comprises a supporting portion (610), a rotating portion (620) and a clamping portion (630); the rotating portion (620) is arranged on the supporting portion (610); the rotating portion (620) can be rotated or locked relative to the supporting portion (610); the clamping portion (630) is arranged on the rotating portion (620); there are a plurality of clamping portions (630), and the plurality of clamping portions (630) are used to cooperate and clamp the cylinder (500) to be welded.

3. The multi-axis linkage local vacuum laser welding device for longitudinal and annular seams of a cylinder as claimed in claim 2, characterized in that: The clamping portion (630) is capable of synchronously moving along the radial direction of the cylinder (500) to be welded.

4. The multi-axis linkage local vacuum laser welding device for longitudinal and annular seams of a cylinder as claimed in claim 1, characterized in that: A first connection portion (310) and a second through hole are provided on the pressure plate (300); the multi-axis mechanical arm (700) is fixedly connected to the first connection portion (310); and the smoke protection component (200) is fixedly arranged in the second through hole.

5. The multi-axis linkage local vacuum laser welding device for longitudinal and annular seams of a cylinder as claimed in claim 1, characterized in that: The sliding sealing assembly (400) comprises a sealing plate, a first through hole (410) is arranged at the center of the sealing plate, the first through hole (410) is sealed and assembled with the smoke protection assembly (200), the laser emitted by the laser welding gun (100) can pass through the first through hole (410) to weld the cylinder (500) to be welded, an elastic sealing assembly (440) is arranged on a side of the sealing plate away from the laser welding gun (100), the elastic sealing assembly (440) protrudes from the sealing plate and extends in the direction of the cylinder (500) to be welded, and the sealing plate and the elastic sealing assembly (440) are both arc-shaped surfaces on one side close to the cylinder (500) to be welded.

6. The multi-axis linkage partial vacuum laser welding device for longitudinal and annular seams of a cylinder as claimed in claim 5, characterized in that: A first accommodating groove (450) and a second accommodating groove (460) are arranged on a side of the sealing plate away from the laser welding gun (100); the first accommodating groove (450) and the second accommodating groove (460) are both arranged in a closed ring shape, and the center of the first accommodating groove (450) and the center of the second accommodating groove (460) coincide with the center of the sealing plate; the elastic sealing assembly (440) comprises a first sealing ring (441) and a second sealing ring (442); the first sealing ring (441) is arranged in the first accommodating groove (450), and the first sealing ring (441) and the first accommodating groove (450) are interference-fitted; the second sealing ring (442) is arranged in the second accommodating groove (460), and the second sealing ring (442) and the second accommodating groove (460) are interference-fitted.

7. The multi-axis linkage local vacuum laser welding device for longitudinal and annular seams of a cylinder as claimed in claim 1, characterized in that: The air extraction component comprises an air extraction pipe (430) and an air extraction pump; one end of the air extraction pipe (430) is connected to the inner cavity of the local sealed welding area, and the other end is connected to the air extraction pump.

8. The multi-axis linkage local vacuum laser welding device for longitudinal and annular seams of a cylinder as claimed in claim 1, characterized in that: The secondary current acquisition and control system also includes a load resistor, an electrical signal amplification module, an electrical signal analysis module, and a comparison control module. The load resistor is connected to the secondary current collecting electrode to form a load loop for real-time collection of secondary current signals. The electrical signal amplification module is respectively communicated with the load loop and the electrical signal analysis module for transmission and amplification of secondary current signals. The electrical signal analysis module is used to receive the secondary current signal transmitted by the electrical signal amplification module and analyze to obtain the secondary current value. The comparison control module is used to compare the secondary current value obtained by the electrical signal analysis module with a preset threshold value and adjust the exhaust speed of the exhaust assembly according to the comparison result.

9. A method for multi-axis linkage local vacuum laser welding of longitudinal and annular seams of a cylinder, using the welding device as described in any one of claims 1 to 8, characterized in that: The welding method comprises: Step S1: Preparation before welding: Process the groove of the cylinder to be welded as required, and process its surface to meet the welding requirements, and then assemble it on the welding device; Step S2: evacuate the welding area to make the vacuum degree meet the welding requirements; Step S3: After the vacuum degree meets the requirement, the laser welding gun is started to perform welding, and the movement of corresponding components is controlled to perform laser welding according to the shape of the weld; Step S4: synchronously detecting the secondary current at a certain position above the molten pool during the welding process, and controlling the exhaust speed of the exhaust component according to the relationship between the secondary current and a preset threshold value; Step S5: After welding is completed, the laser welding gun is turned off, and after a first preset time, the exhaust assembly is turned off.

10. The method for multi-axis linkage partial vacuum laser welding of longitudinal and annular seams of a cylinder as claimed in claim 9, characterized in that: In step S4, controlling the air extraction speed of the air extraction component according to the relationship between the secondary current and the preset threshold value includes: The detected secondary current is compared with a preset threshold value. When it is detected that the secondary current is greater than or equal to the preset threshold value, the suction speed of the suction component is increased. When it is detected that the secondary current is less than the preset threshold value, the suction speed of the suction component is maintained.

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