Local vacuum laser welding device with dust-resistant heat-conducting sleeve

Abstract

The application provides a local vacuum laser welding device with a dustproof heat-conducting sleeve, and belongs to the technical field of vacuum laser welding device design, and comprises a vacuum cover, wherein the vacuum cover comprises a sealing cover body and a vacuum cylinder connected to the side of the sealing cover body away from a workpiece to be welded; a laser incidence port is formed on the sealing cover body; a laser protection lens coaxially arranged with the laser incidence port is arranged in the end of the vacuum cylinder away from the laser incidence port; a dustproof heat-conducting sleeve is arranged in the laser incidence port; the dustproof heat-conducting sleeve is coaxially arranged with the laser incidence port; a cooling flow channel is formed in the dustproof heat-conducting sleeve; and the cooling flow channel is controllably communicated with an external cooling source. The application can separate and deposit smoke dust particles in time by the collision and contact between the inner wall of the cylinder and the pollutant gas flow, and can actively deposit metal vapor in the pollutant gas flow in advance, so that the probability of diffusion of the pollutant gas flow to the laser protection lens arranged at the end of the vacuum cylinder and the deposition of pollution on the lens is effectively reduced.

Description

Technical Field

[0001] This invention belongs to the field of vacuum laser welding equipment design technology, specifically relating to a local vacuum laser welding device with a dust-blocking and heat-conducting sleeve. Background Technology

[0002] Laser welding, with its advantages of high energy density and small heat-affected zone, is widely used in aerospace, shipbuilding, and nuclear energy equipment. However, the plasma plume generated by laser welding in the atmosphere shields the laser energy, resulting in limited penetration depth and making it difficult to meet the requirements for one-time forming of thick plate components. Vacuum laser welding technology effectively suppresses plasma by creating a negative pressure environment, significantly improving penetration depth. However, for large components tens of meters long, constructing a full vacuum chamber is costly and has low engineering feasibility.

[0003] Although full-vacuum laser welding significantly reduces the vacuum level, enabling the welding of thick plate components, constructing a full-vacuum chamber is costly and difficult to manufacture for large components tens or even hundreds of meters in length. In reality, most components only require welding in localized areas. Therefore, localized vacuum laser welding has become the preferred method for large, thick-walled equipment, offering high efficiency, reliability, and cost-effectiveness. The key lies in creating a stable localized vacuum environment in the weld area, preventing the molten pool from contacting air during welding and causing defects such as oxidation, porosity, and slag inclusions. Thus, the reliability of the sealing structure directly affects the welding quality.

[0004] However, in a localized vacuum environment, the keyhole effect generated by laser deep penetration welding leads to violent metal evaporation, forming a large number of high-temperature, high-speed spatter particles. These spatter particles have complex movement paths and are easily ejected upwards to the laser aperture, contaminating or damaging the laser protective lens at the top of the vacuum chamber. The laser protective lens is a core optical component of the laser welding system; once its surface is contaminated by spatter, it will cause laser energy attenuation, focus drift, or even permanent damage to the lens (high-temperature cracking), severely reducing the welding quality. Summary of the Invention

[0005] Therefore, the present invention provides a local vacuum laser welding device with a dust-blocking and heat-conducting sleeve, which can overcome the pollution problems of laser protective lenses in related local vacuum laser welding devices, such as particle adhesion, metal vapor sublimation and deposition, high-temperature ablation and oxidation, which lead to a decrease in welding power, a reduction in weld quality, and a risk of lens high-temperature cracking during long-term welding.

[0006] To address the aforementioned problems, this invention provides a local vacuum laser welding device with a dust-blocking and heat-conducting sleeve, comprising a vacuum hood, the vacuum hood including a sealing hood body and a vacuum cylinder connected to the side of the sealing hood body away from the workpiece to be welded, a laser inlet formed on the sealing hood body, a laser protection lens coaxially disposed with the laser inlet body at the end of the vacuum cylinder away from the laser inlet body, a dust-blocking and heat-conducting sleeve disposed inside the laser inlet body, the dust-blocking and heat-conducting sleeve being coaxially disposed with the laser inlet body, a cooling channel formed inside the dust-blocking and heat-conducting sleeve, and the cooling channel being controllably connected to an external cooling source.

[0007] In some embodiments, the inner wall diameter of the dust-blocking and heat-conducting sleeve at the end near the workpiece to be welded is larger than the inner wall diameter at the end near the laser protection lens, so as to form a dust diffusion space at the end of the dust-blocking and heat-conducting sleeve near the workpiece to be welded.

[0008] In some embodiments, the cooling channels have multiple channels evenly spaced around the central axis of the dust-blocking and heat-conducting sleeve, with the inlet end of each cooling channel located on the side of the outlet end closer to the workpiece to be welded, and the cooling channels extending in a straight line.

[0009] In some embodiments, the dust-blocking and heat-conducting sleeve has a flow-dividing annular groove at one end near the workpiece to be welded, and the inlet end of each cooling channel is connected to the flow-dividing annular groove.

[0010] In some embodiments, the cooling medium in the cooling channels is an inert pressurized gas, and each cooling channel is provided with an airflow nozzle at its outlet end. Each airflow nozzle is arranged around the outer periphery of the dust-blocking and heat-conducting sleeve away from the workpiece to be welded, so as to form a radial planar air curtain.

[0011] In some embodiments, each of the airflow nozzles is arranged in two layers along a direction away from the workpiece to be welded to form a double-layered radial planar air curtain.

[0012] In some embodiments, the end of the dust-blocking and heat-conducting sleeve away from the workpiece to be welded protrudes from the side of the sealing cover away from the workpiece to extend into the vacuum cylinder.

[0013] In some embodiments, the vacuum cylinder has a vacuum port located in the area between each of the airflow nozzles and the laser protective lens.

[0014] In some embodiments, the inner wall of the dust-blocking and heat-conducting sleeve is provided with a plurality of coaxially arranged annular grooves, and each of the annular grooves is spaced apart along the axial direction of the dust-blocking and heat-conducting sleeve.

[0015] In some embodiments, the opening of each of the annular grooves is higher than the bottom of the groove.

[0016] The local vacuum laser welding device with a dust-blocking and heat-conducting sleeve provided by the present invention has the following beneficial effects:

[0017] A dust-blocking and heat-conducting sleeve is coaxially installed inside the laser inlet. On the one hand, the collision and contact between its inner wall and the contaminant gas flow (such as the fumes and metal vapors generated during the welding process) can facilitate the timely separation and deposition of dust particles. On the other hand, the cooling medium in its internal cooling channel can cool the dust-blocking and heat-conducting sleeve in a timely manner, causing the metal vapors in the aforementioned contaminant gas flow to actively sublimate and deposit in advance. This effectively reduces the probability of the contaminant gas flow further diffusing towards the laser protection lens at the end of the vacuum cylinder and depositing contaminants on the lens. In addition, the dust-blocking and heat-conducting sleeve in this invention can also physically intercept the spatter generated during welding and achieve physical isolation of high temperature. This can reduce the risk of high-temperature spatter particles and high temperature burning to the sealing ring around the vacuum chamber, and significantly improve the service life of the laser protection lens and sealing ring. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. The drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0019] Figure 1 This is a structural disassembly diagram of a local vacuum laser welding device with a dust-blocking and heat-conducting sleeve in one embodiment of the present invention.

[0020] Figure 2 yes Figure 1 A bottom view of the local vacuum laser welding device in use (including the sealing ring).

[0021] Figure 3 yes Figure 1 A schematic diagram of the structure of the dust-blocking and heat-conducting sleeve in the middle;

[0022] Figure 4 yes Figure 3 A schematic diagram of the cross-section of the dust-blocking and heat-conducting sleeve in the middle;

[0023] Figure 5 These are comparative photographs showing the spatter adhesion on the inner surface of the laser protective lens after local vacuum welding using the improved local vacuum laser welding device and the original local vacuum laser welding device. Figure 5(a) A photograph showing the spatter adhesion on the inner surface of the laser protective lens after local vacuum welding using the improved local vacuum laser welding device (corresponding to Example 1). Figure 5 (b) is a photograph of the spatter adhesion on the inner surface of the laser protective lens after local vacuum welding using the original local vacuum laser welding device (corresponding to Scale 1).

[0024] The attached figures are labeled as follows:

[0025] 1. Vacuum shroud; 11. Sealed shroud; 110. Laser entrance port; 111. Connecting pipe; 12. Vacuum cylinder; 121. Vacuum extraction interface; 13. Sealing ring; 2. Laser protection lens; 3. Dust-proof and heat-conducting sleeve; 31. Cooling channel; 32. Airflow nozzle; 33. Flow divider groove; 331. Inlet pipe; 34. Annular groove; 35. Connecting lug. Detailed Implementation

[0026] 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. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. 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.

[0027] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0028] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90° or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0029] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0030] See also Figures 1 to 5 As shown in the figure, according to an embodiment of the present invention, a local vacuum laser welding device with a dust-blocking and heat-conducting sleeve is provided, including a vacuum hood 1. The vacuum hood 1 includes a sealing hood body 11 and a vacuum cylinder 12 connected to the side of the sealing hood body 11 away from the workpiece to be welded (not shown in the figure). A sealing ring 13 is provided on the end face of the sealing hood body 11 that mates with the workpiece to be welded. Generally, the sealing ring 13 should have a certain elastic deformation capacity and high temperature resistance and wear resistance to ensure the sealing isolation effect between the sealing hood body 11 and the surface of the workpiece to be welded during the welding process. A laser inlet 110 is formed on the sealing hood body 11, and the vacuum cylinder 12 is located at the end away from the laser inlet 110. A laser protection lens 2 is provided, which is coaxially arranged with the laser entrance 110. A dust-blocking and heat-conducting sleeve 3 is provided inside the laser entrance 110. The dust-blocking and heat-conducting sleeve 3 is coaxially arranged with the laser entrance 110. A cooling channel 31 is formed inside the dust-blocking and heat-conducting sleeve 3. The cooling channel 31 is controllably connected to an external cooling source. It is understood that the diameter of the inner wall of the aforementioned dust-blocking and heat-conducting sleeve 3 should be larger than the diameter of the laser beam to ensure that the laser beam can be directed to the welding area of ​​the workpiece below without obstruction. It should be noted that the diameter of the inner wall of the aforementioned dust-blocking and heat-conducting sleeve 3 should not be too small in principle, and should at least form a surrounding enclosure of the molten pool formed during welding on the workpiece.

[0031] In this technical solution, a dust-blocking and heat-conducting sleeve 3 is coaxially arranged inside the laser inlet 110. On the one hand, the collision and contact between its inner wall and the contaminant airflow (such as the fumes and metal vapors generated during the welding process) can form timely separation and deposition of dust particles. On the other hand, the cooling medium in its internal cooling channel 31 can cool and reduce the temperature of the dust-blocking and heat-conducting sleeve 3 in time, so that the metal vapors in the aforementioned contaminant airflow will be actively condensed and deposited in advance. This effectively reduces the probability that the contaminant airflow will further diffuse toward the laser protection lens 2 set at the end of the vacuum cylinder 12 and deposit contaminants on the lens. In addition, the dust-blocking and heat-conducting sleeve 3 in this invention can also physically block the spatter generated during welding and achieve physical isolation of high temperature. This can reduce the risk of burns to the sealing ring 13 around the sealing cover 11 caused by high temperature spatter particles and high temperature, and significantly improve the service life of the laser protection lens 2 and the sealing ring 13.

[0032] It is understandable that during the vacuum welding process, a large amount of plasma, metal vapor, fumes and other pollutants will be generated at the weld pool. These pollutants will enter the vacuum cylinder 12 upwards from the laser inlet 110 in the form of airflow diffusion. Due to the aforementioned dust-blocking and heat-conducting sleeve 3 of the present invention, the pollutant fluid will expand, be intercepted and slowed down by the inner wall of the dust-blocking and heat-conducting sleeve 3. Most of the particulate matter (including metal vapor) in the pollutants will be intercepted and deposited when it flows through the dust-blocking and heat-conducting sleeve 3, thereby reducing the deposition and frost formation of the pollutant fluid on the aforementioned laser protection lens 2. It is worth emphasizing that the metal vapor in the pollutant fluid will be pre-deposited on the dust-blocking and heat-conducting sleeve 3, thereby achieving substitute protection for the laser protection lens 2.

[0033] In a like Figure 1 In the illustrated embodiment, the aforementioned dust-blocking and heat-conducting sleeve 3 is an overall cylindrical sleeve structure. In this case, based on the diffusion requirements of plasma and other fumes at the weld location, the inner diameter of the dust-blocking and heat-conducting sleeve 3 needs to be designed to be relatively large in order to reduce the concentration of welding fumes and thus reduce the reduction of laser power caused by fumes. However, this structure with the same diameter at the top and bottom results in an excessively large diameter at the end away from the weld, and the movement limit of the contaminant fluid toward the aforementioned laser protection lens 2 is relatively low. In some embodiments, the inner diameter of the dust-blocking and heat-conducting sleeve 3 at the end near the workpiece to be welded is larger than the inner diameter of the end near the laser protection lens 2, so as to form a fume diffusion space at the end of the dust-blocking and heat-conducting sleeve 3 near the workpiece to be welded (not indicated in the figure).

[0034] In this technical solution, the inner wall diameter of the dust-blocking and heat-conducting sleeve 3 is designed to be larger at the end closer to the workpiece to be welded, i.e. the weld seam, and smaller at the end farther away from the weld seam. This ensures that the fumes generated during welding in the weld seam area have a sufficiently large diffusion space, prevents excessive concentration from causing power attenuation of the laser beam, and also suppresses the upward movement of fumes, reducing the upward speed and throughput of the fumes passing through the end of the dust-blocking and heat-conducting sleeve 3 away from the weld seam. This is beneficial to further reduce the deposition of fumes and other pollutants on the laser protective lens 2.

[0035] It is understandable that the smaller diameter of the inner wall of the aforementioned dust-blocking and heat-conducting sleeve 3 (i.e., the top) should be larger than the maximum diameter of the laser beam corresponding to that position, so as to prevent the dust-blocking and heat-conducting sleeve 3 from blocking or hindering the propagation of the laser beam.

[0036] In some embodiments, the cooling channel 31 has multiple channels evenly spaced around the central axis of the dust-blocking and heat-conducting sleeve 3, with the inlet end of each cooling channel 31 located on the side of the outlet end closer to the workpiece to be welded, and the cooling channel 31 extending in a straight line.

[0037] In this technical solution, multiple straight cooling channels 31 are arranged at intervals around the central axis inside the dustproof and heat-conducting sleeve 3. This can achieve a relatively uniform cooling effect on the entire circumference of the dustproof and heat-conducting sleeve 3, ensure the circumferential uniformity of the thermal deformation of the dustproof and heat-conducting sleeve 3, and prevent the uncontrollable deformation of the inner diameter of the dustproof and heat-conducting sleeve 3 from interfering with the propagation of the laser beam. On the other hand, the straight cooling channels 31 have less resistance to the cooling medium.

[0038] In some embodiments, the dust-blocking and heat-conducting sleeve 3 is frustum-shaped, which facilitates the construction of straight cooling channels 31 within it, in which case each cooling channel 31 extends along the generatrix of the frustum.

[0039] In some embodiments, the dust-blocking and heat-conducting sleeve 3 has a flow-dividing annular groove 33 at one end near the workpiece to be welded, and the inlet end of each cooling channel 31 is connected to the flow-dividing annular groove 33.

[0040] In this technical solution, an annular flow-dividing groove 33 is set inside the bottom end of the dust-blocking and heat-conducting sleeve 3 to simultaneously connect the inlet ends of each cooling channel 31, so that the external cooling medium can enter each cooling channel 31 evenly, making the structure more reasonable and simpler. It can be understood that the aforementioned flow-dividing groove 33 has an inlet pipe 331 connected to it, and a corresponding connecting pipe 111 is provided on the sealing cover 11. The inlet pipe 331 is inserted into the connecting pipe 111 and is sealed and connected to the flow-dividing groove 33. The other end of the inlet pipe 331 is controllably connected to an external cooling medium source.

[0041] In one feasible embodiment, the aforementioned cooling medium can be a coolant. In this case, a corresponding outlet pipe structure needs to be set on the dust-blocking and heat-conducting sleeve 3 to form a circulating drive for the coolant. Using coolant as the cooling medium has a high cooling effect, but it has high requirements for structural matching. As a better implementation method, the cooling medium in the cooling channel 31 is an inert pressure gas (e.g., argon or nitrogen). Each cooling channel 31 has an airflow nozzle 32 at its outlet end. Each airflow nozzle 32 is arranged around the outer periphery of the opening of the dust-blocking and heat-conducting sleeve 3 away from the workpiece to be welded. Each airflow nozzle 32 sprays out from the outside to the inside along the diameter direction of the dust-blocking and heat-conducting sleeve 3 to form a radial planar air curtain.

[0042] In this technical solution, airflow nozzles 32 are set on each cooling channel 31 to spray the cooling medium after heat exchange with the dustproof and heat-conducting sleeve 3 along its radial direction to form a radial planar air curtain, which further forms an air curtain to cut off the top opening of the dustproof and heat-conducting sleeve 3, thereby further blocking the upward flow of pollutants to the laser protection lens 2 for deposition.

[0043] It should be noted that the inlet of the cooling channel 31 in this invention is at the bottom and the outlet is at the top, so that the pressurized fluid sprayed by each airflow nozzle 32 is far away from the weld pool, which can minimize the disturbance of the pressurized fluid to the weld pool and ensure the forming quality of the weld.

[0044] In some embodiments, each of the airflow nozzles 32 is arranged in two layers along the direction away from the workpiece to be welded to form a double-layer radial plane air curtain. Preferably, the airflow nozzles 32 corresponding to the upper radial plane air curtain and the airflow nozzles 32 corresponding to the lower radial plane air curtain are arranged alternately along the circumferential direction of the dust-blocking and heat-conducting sleeve 3, so that the two layers of radial plane air curtains formed by the upper and lower airflow nozzles 32 are completely and evenly distributed in the entire radial plane of the dust-blocking and heat-conducting sleeve 3, that is, forming a 360° air curtain to block dust at the top end of the dust-blocking and heat-conducting sleeve 3, further reducing the amount of smoke and dust escaping into the vacuum cylinder 12.

[0045] In some embodiments, the supply pressure of the aforementioned inert gas (i.e., the supply pressure of the aforementioned external cooling source) is 0.05-10 MPa, which can be reasonably selected according to actual needs. The number of airflow nozzles 32 and the nozzle orifice diameter can be selected according to the diameter of the top opening of the actual dust-blocking and heat-conducting sleeve 3. In some embodiments, the number of airflow nozzles 32 per layer can be 6 to 24, and the orifice diameter of each airflow nozzle 32 is 0.3 to 1.2 mm.

[0046] In some embodiments, the end of the dust-blocking and heat-conducting sleeve 3 away from the workpiece to be welded protrudes from the end face of the sealing cover 11 away from the workpiece to extend into the vacuum cylinder 12, see details below. Figure 1 As shown, the top end of the dust-blocking and heat-conducting sleeve 3 extends into the vacuum cylinder 12, thereby increasing the axial length of the dust-blocking and heat-conducting sleeve 3.

[0047] In this technical solution, since the dust-blocking and heat-conducting sleeve 3 has a portion that protrudes from the top surface of the sealing cover 11 and extends into the vacuum cylinder 12, it has a larger inner wall area, and the diffusion space of the dust is also relatively larger. This can increase the contact time between the dust flow and the inner wall of the dust-blocking and heat-conducting sleeve 3, increase the probability and duration of the action due to collision, contact and condensation, and improve the separation and deposition effect of particles and metal vapor in the dust flow.

[0048] It is understood that, in order to ensure the vacuum level inside the vacuum chamber 1, the vacuum chamber 1 is provided with a vacuum port 121, which is controllably connected to a vacuum pump, so that the vacuum chamber 1 can be evacuated in real time during the welding process to ensure that the vacuum level is within the target value range. This can also compensate for the small-scale disruption of the vacuum level inside the chamber caused by the aforementioned inert pressure gas (positive pressure). As a preferred embodiment, the vacuum port 121 is set on the vacuum cylinder 12 and the vacuum port 121 is located in the area between each of the airflow nozzles 32 and the laser protection lens 2. In this way, the suction effect can be used to simultaneously remove a small amount of smoke and dust that has passed through the aforementioned double-layer radial air curtain from the vacuum cylinder 12 and discharge it during the vacuuming process. At the same time, it can also reduce the adverse disturbance of the gas curtain to the molten pool below.

[0049] In practical applications, a corresponding vacuum detection sensor is installed on the sealing cover 11 to detect the vacuum level inside the sealing cover 11 in real time and feed it back to the corresponding control components so as to adjust the start and stop of the aforementioned vacuum pump in real time and ensure that the vacuum level is within the preset range.

[0050] In some implementation methods, see details. Figure 4 As shown, the inner wall of the dust-blocking and heat-conducting sleeve 3 is provided with a plurality of coaxially arranged annular grooves 34, and each of the annular grooves 34 is spaced apart along the axial direction of the dust-blocking and heat-conducting sleeve 3.

[0051] In this technical solution, by further setting multiple annular grooves 34 spaced vertically on the inner wall of the dust-blocking and heat-conducting sleeve 3, the outer surface area of ​​the inner wall of the sleeve can be further increased, which can further improve the contact probability between the pollutant airflow (smoke and dust airflow, etc.) and the dust-blocking and heat-conducting sleeve 3. This means that the airflow can have more sufficient contact and collision with the inner wall of the sleeve, thereby improving the separation of particulate matter such as smoke and dust and the condensation effect of metal vapor. On the other hand, each annular groove 34 can also guide the pollutant airflow within it to form turbulent flow, further ensuring sufficient contact between the airflow and the inner wall of the sleeve.

[0052] In some embodiments not shown, the opening of each annular groove 34 is higher than the bottom of the groove, and each annular groove 34 is a constricted groove. Thus, from the cross-section of each annular groove 34 (the axial section of the dust-blocking and heat-conducting sleeve 3), each annular groove 34 objectively forms a receiving cavity. This receiving cavity is similar to a pocket structure with a constricted opening, which can contain the separated dust particles, condensed metal particles, etc., and prevent these particles from falling back into the weld pool below and reducing the weld quality.

[0053] The aforementioned dust-blocking and heat-conducting sleeve 3 can be made of heat-conducting materials such as stainless steel, titanium alloy, or high-temperature alloy. The surface roughness Ra of the inner wall of the sleeve is ≤5μm. In some embodiments, the inner wall of the dust-blocking and heat-conducting sleeve 3 has a high-temperature resistant anti-sticking layer. Specifically, the aforementioned high-temperature resistant anti-sticking layer can be a nano-ceramic coating, a diamond-like carbon coating, or a nickel-based high-temperature alloy coating. The coating thickness is 10-200μm, and the bonding strength between the coating and the metal substrate (i.e., the inner wall of the sleeve) is not less than 30 MPa, ensuring that it does not peel off under repeated thermal cycling. In some embodiments, the temperature resistance of the aforementioned high-temperature resistant anti-sticking layer is generally not less than 800℃.

[0054] In this technical solution, by setting a high-temperature resistant anti-sticking layer on the inner wall of the dust-blocking and heat-conducting sleeve 3, the degree of adhesion between particles, especially condensed (sublimated) metal particles, and the inner wall of the sleeve can be reduced, which is conducive to the subsequent cleaning, maintenance and reuse of the dust-blocking and heat-conducting sleeve 3.

[0055] In some embodiments, the wall thickness of the aforementioned dust-blocking and heat-conducting sleeve 3 can be 0.5 to 15 mm, and can be reasonably selected according to actual needs.

[0056] The dust-blocking and heat-conducting sleeve 3 is detachably connected to the sealing cover 11. For example, the dust-blocking and heat-conducting sleeve 3 can be directly threaded to the laser inlet 110. In a simpler implementation, a corresponding connecting lug 35 is provided on the outer wall of the dust-blocking and heat-conducting sleeve 3. The dust-blocking and heat-conducting sleeve 3 can be bolted to the sealing cover 11 by the connecting lug 35. The processing is simpler. When the dust-blocking effect decreases due to long-term use, it can be removed for cleaning or a new dust-blocking and heat-conducting sleeve 3 can be directly replaced.

[0057] The specific application should be carried out according to the following steps:

[0058] Step 1: Install the dust-blocking and heat-conducting sleeve 3 inside the vacuum chamber at the laser light port (i.e., the aforementioned laser entrance port 110), and connect the gas supply line (i.e., provide inert gas).

[0059] Step 2: Place the vacuum hood on the surface of the workpiece (i.e., the workpiece to be welded) and press down to make the bottom flexible sealing material (i.e., the aforementioned sealing ring 13) adhere to the workpiece;

[0060] Step 3: Activate the double-layer annular air curtain (i.e., the aforementioned radial planar air curtain).

[0061] Step 4: Start the vacuum pump to evacuate air, and use the dynamic vacuum control system to adjust and stabilize the vacuum level inside the vacuum chamber to the preset value;

[0062] Step 5: With the dynamic vacuum control system on, laser welding begins; during the welding process, the dynamic vacuum control system automatically adjusts the pumping rate based on real-time feedback from the vacuum sensor to compensate for the amount of gas introduced by the continuous gas supply from the double-layer annular air curtain, thereby controlling the vacuum fluctuation within a preset range.

[0063] Step 6: During the welding process, the inner wall of the dust-blocking and heat-conducting sleeve 3 and the double-layer air curtain work together to block spatter.

[0064] Step 7: After welding is completed, turn off the laser and vacuum pump, and remove the vacuum hood after cooling.

[0065] The technical solution of the present invention is further illustrated below with reference to several embodiments and comparative examples:

[0066] Example 1

[0067] A 40 mm thick high-strength steel plate was selected and subjected to a local vacuum laser welding test using the local vacuum laser welding device with dust-blocking and heat-conducting sleeve of the present invention.

[0068] The guide tube (also known as the aforementioned dust-blocking and heat-conducting sleeve 3) is made of stainless steel, with a length of 10 mm, an inner diameter of 35 mm, and a wall thickness of 3 mm. The vacuum hood (also known as the aforementioned vacuum hood 1) is placed on the surface of the workpiece, and the sealing ring (also known as the aforementioned sealing ring 13) is pressed down to fit against the surface of the workpiece. The double-layer annular air curtain is activated, and the vacuum pump is started. Welding begins after the vacuum level reaches 8 Pa. Welding parameters: laser power 10 kW, welding speed 0.5 m / min.

[0069] Technical Results and Analysis: The welding process was stable throughout. Post-weld inspection revealed that the surface of the focusing lens (i.e., the aforementioned laser protective lens 2) was smooth and free of any spatter. Figure 5 As shown in (a), a small number of fine spherical splash particles are attached to the inner wall of the guide tube. They have all solidified and can be easily wiped off by hand. There is no obvious melting and bonding phenomenon. The temperature in the area of ​​the light-transmitting port at the top of the vacuum hood (i.e., the aforementioned laser entrance port 110) does not rise significantly. The weld formation is good and the penetration depth reaches the expected level.

[0070] Comparative Example 1

[0071] Select 40 mm thick high-strength steel plates of the same specifications and use vacuum hoods of the same specifications, but without any guide tubes or protective devices inside. The focusing lens is directly exposed in the local vacuum chamber. Start the vacuum pump and start welding after the vacuum degree reaches 8 Pa. Welding parameters: laser power 10 kW, welding speed 0.5 m / min.

[0072] Technical effects and analysis: Approximately 15 seconds after welding began, spatter particles started to contaminate the lens. Slight fluctuations in the laser power display were observed. At 40 seconds of welding, the lens contamination intensified. Figure 5 As shown in (b), the power display value dropped significantly. After welding, the lens was removed for inspection. The lens surface was covered with a dense layer of metal spatter particles and vapor condensation film, and some areas showed signs of burns from high-temperature particles. The lens was no longer usable and needed to be replaced.

[0073] Comparative Example 2

[0074] Select 40 mm thick high-strength steel plates of the same specifications. A flow guide tube (same structure as in Example 1) is installed inside the vacuum chamber, but the double-layer annular gas curtain is not activated. Start the vacuum pump, and begin welding after the vacuum level reaches 8 Pa. Welding parameters: laser power 10 kW, welding speed 0.5 m / min.

[0075] Technical Effects and Analysis: In the initial welding stage, spatter particles were intercepted by the guide tube, preventing direct contamination of the lens. As welding progressed, the guide tube continuously absorbed heat from the spatter and thermal radiation, causing its temperature to rise rapidly. After one minute of welding, the inner wall of the guide tube became excessively hot, and some spatter particles, after impact, molten and adhered to the tube wall, forming a slag layer. By the end of welding, a large amount of molten slag had accumulated on the inner wall of the guide tube, partially obstructing the optical path. Simultaneously, heat was conducted to the top of the vacuum chamber, significantly increasing the temperature of the light-transmitting area, making it feel hot to the touch. Although the lens was not directly impacted by spatter, the increased temperature due to thermal radiation may affect its long-term stability.

[0076] Comparative Example 3

[0077] High-strength steel plates of the same specifications, 40 mm thick, were selected. A flow guide tube (same structure as in Example 1) was installed inside the vacuum chamber. Only a single-layer annular gas curtain was installed inside the bottom wall of the flow guide tube. The vacuum pump was started, and welding began after the vacuum level reached 8 Pa. Welding parameters: laser power 10 kW, welding speed 0.5 m / min.

[0078] Technical effects and analysis: The protection is acceptable under normal parameters (0.5 m / min), with no contamination of the lens and no slag accumulation on the cylinder wall. However, when the welding speed is increased to 1.2 m / min and spatter intensifies, a blind spot appears in the circumferential gap area between the jet nozzles of the single-layer air curtain. Tiny spatter particles penetrate through the gap of the air curtain and adhere to the corresponding position on the upper part of the cylinder wall. Although the coating prevents it from being firmly fused, long-term continuous welding will lead to the accumulation of adhering substances, requiring periodic shutdown for cleaning.

[0079] It will be readily understood by those skilled in the art that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0080] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A local vacuum laser welding device with a dust-blocking and heat-conducting sleeve, characterized in that, The system includes a vacuum hood (1), which includes a sealing hood (11) and a vacuum cylinder (12) connected to the side of the sealing hood (11) away from the workpiece to be welded. A laser inlet (110) is formed on the sealing hood (11). A laser protection lens (2) is provided in the end of the vacuum cylinder (12) away from the laser inlet (110) and is coaxially arranged with the laser inlet (110). A dustproof and heat-conducting sleeve (3) is provided in the laser inlet (110) and is coaxially arranged with the laser inlet (110). A cooling channel (31) is formed in the dustproof and heat-conducting sleeve (3) and is controllably connected to an external cooling source.

2. The local vacuum laser welding apparatus according to claim 1, characterized in that, The inner wall diameter of the dust-blocking and heat-conducting sleeve (3) at the end near the workpiece to be welded is larger than the inner wall diameter at the end near the laser protection lens (2), so as to form a dust diffusion space at the end of the dust-blocking and heat-conducting sleeve (3) near the workpiece to be welded.

3. The local vacuum laser welding apparatus according to claim 2, characterized in that, The cooling channel (31) has multiple channels evenly spaced around the central axis of the dustproof and heat-conducting sleeve (3). The inlet end of each cooling channel (31) is located on the side of the outlet end close to the workpiece to be welded, and the cooling channel (31) extends in a straight line.

4. The local vacuum laser welding apparatus according to claim 3, characterized in that, The dust-blocking and heat-conducting sleeve (3) has a flow-dividing ring groove (33) at one end near the workpiece to be welded, and the inlet end of each cooling channel (31) is connected to the flow-dividing ring groove (33).

5. The local vacuum laser welding apparatus according to claim 3, characterized in that, The cooling medium in the cooling channel (31) is an inert pressure gas. Each cooling channel (31) is provided with an airflow nozzle (32) at its outlet end. Each airflow nozzle (32) is arranged around the outer periphery of the dustproof and heat-conducting sleeve (3) away from the workpiece to be welded, so as to form a radial planar air curtain.

6. The local vacuum laser welding apparatus according to claim 5, characterized in that, Each of the airflow nozzles (32) is arranged in two layers along the direction away from the workpiece to be welded to form a double-layer radial plane air curtain.

7. The local vacuum laser welding apparatus according to claim 5, characterized in that, The dust-blocking and heat-conducting sleeve (3) protrudes from the side of the sealing cover (11) away from the workpiece to be welded, so as to extend into the vacuum cylinder (12).

8. The local vacuum laser welding apparatus according to claim 7, characterized in that, The vacuum cylinder (12) has a vacuum port (121) located in the area between each of the airflow nozzles (32) and the laser protection lens (2).

9. The local vacuum laser welding apparatus according to claim 1, characterized in that, The inner wall of the dust-blocking and heat-conducting sleeve (3) is provided with a plurality of coaxially arranged annular grooves (34), and each of the annular grooves (34) is spaced apart along the axial direction of the dust-blocking and heat-conducting sleeve (3).

10. The local vacuum laser welding apparatus according to claim 9, characterized in that, The opening of each of the annular grooves (34) is higher than the bottom of the groove.

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