Partial vacuum laser welding device configured with a spatter barrier structure

Abstract

The application provides a local vacuum laser welding device configured with a splash blocking structure, and belongs to the technical field of vacuum laser welding device design, which comprises a vacuum cover, the vacuum cover comprises a sealed cover body, a laser incidence port is formed on the sealed cover body, the end face of the sealed cover body near the side of a workpiece to be welded is a first end face, a sealing ring surrounding the laser incidence port is arranged on the peripheral area of the first end face, a splash blocking structure is further arranged in the area surrounded by the sealing ring, the splash blocking structure is arranged in at least two groups, each group of the splash blocking structure is arranged on the two sides of the laser incidence port along the length direction of the weld of the workpiece to be welded, and each group of the splash blocking structure is connected with the first end face. The application can avoid the sealing damage of the sealing ring caused by splashes, thereby ensuring the reliable stability of the vacuum environment of the local vacuum laser welding device and effectively ensuring the welding quality.

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 equipped with a spatter blocking structure. 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, the sealing material (i.e., the sealing ring) faces a serious risk of failure during the welding process:

[0005] Firstly, the direct impact of high-temperature metal spatter. During laser deep penetration welding, the keyhole effect causes the metal to evaporate violently, forming a large number of high-speed spatter particles (temperature can reach over 2000℃, speed 15~20 m / s). These high-temperature particles sputter onto the flexible sealing material, causing: (1) physical damage - the high-temperature particles melt or burn the sealing surface, forming uneven defects; (2) slag failure - after the spatter cools, it adheres to the sealing surface, causing the sealing material to be unable to fit tightly against the workpiece; (3) microscopic leakage channels - slag is embedded in the sealing material, destroying the integrity of the seal.

[0006] Secondly, there is indirect damage from welding heat radiation. Even if spatter particles do not directly impact the weld, the high temperature of several thousand degrees Celsius in the weld area will continue to heat the sealing material through heat radiation. Long-term heat accumulation causes polymer sealing materials to soften, decompose, or even ablate, while metallic sealing materials may create gaps with the workpiece due to thermal expansion. Once the seal fails, outside air enters the local vacuum cavity, causing a sharp drop in vacuum level. This not only leads to weld oxidation but also interferes with laser energy transmission due to the re-expansion of the plasma plume, potentially forcing the welding process to be interrupted.

[0007] To address this issue, existing technologies often involve optimizing the sealing ring itself, such as developing high-temperature resistant coatings or composite sealing structures. However, due to the characteristics of its flexible material, the optimized sealing ring has limited ability to resist direct splash impacts, and the slag formed by splashes will damage the sealing surface, leading to unreliable local vacuum environment (reduced sealing effect) and lower vacuum welding quality. Summary of the Invention

[0008] Therefore, the present invention provides a local vacuum laser welding device equipped with a spatter blocking structure, which can overcome the shortcomings of related local vacuum laser welding devices where the sealing ring is impacted by welding spatter during the welding process, resulting in damage to the sealing surface, which in turn leads to an unreliable local vacuum environment and reduced vacuum welding quality.

[0009] To address the aforementioned problems, the present invention provides a local vacuum laser welding apparatus equipped with a spatter blocking structure, comprising a vacuum hood, the vacuum hood including a sealing hood body, a laser inlet formed on the sealing hood body, the end face of the sealing hood body near the workpiece to be welded being a first end face, a sealing ring surrounding the laser inlet being provided on the outer periphery of the first end face, and a spatter blocking structure being provided in the area surrounded by the sealing ring, the spatter blocking structure being provided in at least two sets, each set of the spatter blocking structure being spaced apart on both sides of the laser inlet along the weld length direction of the workpiece to be welded, and each set of the spatter blocking structure being connected to the first end face.

[0010] In some embodiments, each group of spatter blocking structures includes a first blocking plate arranged perpendicular to the length direction of the weld, the end of the first blocking plate near the workpiece to be welded being the bottom end, and the bottom end of the first blocking plate having a weld elastic fitting portion in at least the area corresponding to the weld position.

[0011] In some embodiments, the end of the first blocking plate away from the workpiece to be welded is the top end, and the top end of the first blocking plate is thermally connected to the first end face.

[0012] In some embodiments, each set of spatter blocking structures further includes a second blocking sheet arranged parallel to and spaced apart from the first blocking sheet. The area at the bottom end of the second blocking sheet corresponding to the weld position also has the weld elastic fitting portion. The top end of the second blocking sheet is thermally connected to the first end face, and the second blocking sheet is located on the side of the first blocking sheet away from the laser entrance.

[0013] In some embodiments, the top ends of both the first and second blocking plates are slidably connected to the first end face to adjust the distance between them, and the positions of the first and second blocking plates relative to the sealing cover can be locked.

[0014] In some embodiments, the first end face of the sealing cover has a limiting slide rail extending toward the side of the workpiece to be welded. On the same side of the laser entrance, there are two limiting slide rails, which are arranged parallel to and spaced apart from each other in the length direction of the weld. The top ends of the first blocking plate and the second blocking plate are respectively formed with grooves that encircle the limiting slide rails.

[0015] In some embodiments, the sealing cover has a second end face that is parallel to and opposite to the first end face. An external heat dissipation structure is provided on the second end face, and the position of the external heat dissipation structure corresponds to the position of each group of splash blocking structures and is thermally connected to the sealing cover.

[0016] In some embodiments, the external heat dissipation structure includes heat dissipation fins that are thermally connected to the sealing cover.

[0017] In some embodiments, the heat dissipation fins are provided with a heat pipe structure.

[0018] In some embodiments, at least the first blocking plate has a plurality of reflective strips on the side closest to the laser entrance.

[0019] The local vacuum laser welding device with a spatter blocking structure provided by the present invention has the following beneficial effects:

[0020] Within the sealed space formed by the vacuum enclosure, two sets of spatter blocking structures are spaced apart along the length of the weld. This allows for the physical interception of spatter generated at the weld location during vacuum welding, preventing these high-temperature, high-speed spatter from directly impacting the sealing ring in the same direction. This avoids damage to the sealing ring caused by the spatter, thereby ensuring the reliable and stable vacuum environment of the local vacuum laser welding device and effectively guaranteeing welding quality. Attached Figure Description

[0021] 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.

[0022] Figure 1 This is a structural disassembly diagram of a local vacuum laser welding device with a spatter blocking structure in one embodiment of the present invention;

[0023] Figure 2 yes Figure 1 Bottom view of the local vacuum laser welding device in use.

[0024] Figure 3 yes Figure 1 A three-dimensional structural schematic diagram of the first or second blocking sheet in one embodiment;

[0025] Figure 4 These are comparative photographs showing the spatter adhesion on the workpiece surface after local vacuum welding using the improved local vacuum laser welding device (Figure (a), Example 1) and the unimproved local vacuum laser welding device (Figure (b), Comparative Example 1).

[0026] The attached figures are labeled as follows:

[0027] 1. Vacuum shroud; 11. Sealed shroud; 110. Laser entrance port; 111. First end face; 112. Second end face; 113. Limiting slide rail; 12. Sealing ring; 13. Vacuum cylinder; 131. Laser protection lens; 132. Vacuum extraction interface; 2. Spatter blocking structure; 21. First blocking plate; 211. Elastic fitting part of weld; 2111. Slag receiving bend; 212. Slide groove; 22. Second blocking plate; 31. Heat dissipation fins. Detailed Implementation

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] The inventors discovered that spatter generation during laser deep penetration welding is closely related to keyhole behavior, with the high-speed ejection of metal vapor within the keyhole being the core driving force behind the spatter. Based on fluid dynamics and high-speed camera observations, the front wall of the keyhole is subjected to vapor back pressure, generating "forward spatter" pointing towards the front of the molten pool (e.g., Figure 2 (Left side as shown in the orientation) Due to the collapse of the rear wall of the orifice caused by gravity and the escape of steam, a "backward splash" (e.g.) is formed. Figure 2 (As shown on the right side of the orientation below), the directions of these two spatters are parallel to the welding travel direction, that is, the length extension direction of the weld. In other words, the spatter particles mainly fly out in the length direction of the weld (that is, in front and behind the welding travel direction), rather than spreading laterally to both sides of the weld. Since the spatter flight direction at the front and rear ends is parallel to the sealing strip, the risk of impact is lower. Based on the above findings, in order to reduce the damage of spatter slag to the sealing ring, this invention is proposed.

[0033] See also Figures 1 to 4As shown in the embodiment of the present invention, a local vacuum laser welding device with a spatter blocking structure is provided, including a vacuum hood 1. The vacuum hood 1 includes a sealing hood 11, on which a laser inlet 110 is formed. The end face of the sealing hood 11 near the workpiece to be welded is a first end face 111, and the end face parallel to and opposite to the first end face is a second end face 112. A vacuum cylinder 13 coaxially arranged with the laser inlet 110 is connected to the second end face 112. A laser protection lens 131 is provided at the end of the vacuum cylinder 13 away from the laser inlet 110. A surrounding lens is provided on the peripheral area of ​​the first end face 111. The sealing ring 12 of the laser entrance 110 may have at least two layers arranged radially inside and outside the laser entrance 110. It is understood that the sealing ring 12 should be made of a high-temperature resistant and wear-resistant sealing material. The top of the sealing ring 12 is detachably connected to the first end face 111 of the sealing cover 11 to facilitate maintenance and replacement of the sealing ring 12. A spatter blocking structure 2 is also provided in the area surrounded by the sealing ring 12. At least two sets of the spatter blocking structure 2 are provided, with each set spaced along the weld length direction of the workpiece to be welded on both sides of the laser entrance 110. Figure 2 The left and right sides of the indicated orientation, and each set of splash blocking structures 2 is connected to the first end face 111.

[0034] In this technical solution, two sets of spatter blocking structures 2 are arranged at intervals along the length of the weld within the sealed space formed by the vacuum hood 1. This allows for the physical interception of spatter generated at the weld position during the vacuum welding process, preventing the high-temperature, high-speed spatter from directly impacting the sealing ring 12 in the same direction. This avoids damage to the sealing ring 12 due to the spatter, thereby ensuring the reliable and stable vacuum environment of the local vacuum laser welding device and effectively guaranteeing the welding quality.

[0035] In principle, the aforementioned spatter blocking structure 2 can adopt any structure capable of blocking spatter. In some embodiments, each set of spatter blocking structures 2 includes a first blocking plate 21 arranged perpendicular to the length direction of the weld. The end of the first blocking plate 21 closest to the workpiece to be welded is the bottom end. The bottom end of the first blocking plate 21 has a weld elastic fitting portion 211 at least in the area corresponding to the weld position. The aforementioned weld elastic fitting portion 211 can be a part of the first blocking plate 21 or a component independent of the first blocking plate 21, which can be assembled with the first blocking plate 21 as a whole. In a preferred embodiment, in order to minimize the gap between the bottom end of the first blocking plate 21 and the workpiece to be welded, the entire width of the bottom end of the first blocking plate 21 has the aforementioned weld elastic fitting portion 211.

[0036] In this technical solution, by designing the area corresponding to the bottom end of the first blocking plate 21 and the weld position as the weld elastic fitting part 211, the elastic deformation ability of the weld elastic fitting part 211 can be used to maintain a relatively tight fit with the weld, thereby minimizing the leakage of spatter from the gap between the first blocking plate 21 and the weld position and improving its blocking effect on spatter.

[0037] To ensure the splashing ( Figure 2 To intercept as comprehensively as possible in the left and right directions shown, the width of the aforementioned first blocking plate 21 should not be less than twice the weld width (the dimension in the direction perpendicular to its length), and of course, it should not be greater than the inner spacing width of the sealing ring 12 in that direction.

[0038] The weld elastic bonding part 211 is a brush formed by multiple metal strips or wires. It can form a relatively dense barrier wall structure by utilizing the staggered arrangement of the metal strips or wires in the brush, while also having greater elastic deformation flexibility, thereby improving its conformal bonding performance with the weld reinforcement.

[0039] In some embodiments, the end of the first blocking plate 21 away from the workpiece to be welded is the top end, and the top end of the first blocking plate 21 is heat-transfer connected to the first end face 111. It is understood that the first blocking plate 21 and the sealing cover 11 are both made of high-temperature resistant metal materials, such as high-temperature resistant stainless steel or high-temperature alloys.

[0040] In this technical solution, heat is transferred between the top end and the first end face 111. The heat on the first blocking plate 21 can be conducted to the sealing cover 11, and then the large heat dissipation area of ​​the sealing cover 11 itself can be used to quickly dissipate heat to the surrounding environment, reduce the temperature rise of the first blocking plate 21, prevent high temperature splashes from burning the first blocking plate 21, and improve the service life of the first blocking plate 21.

[0041] In some embodiments, each set of spatter blocking structures 2 further includes a second blocking plate 22 arranged parallel to and spaced apart from the first blocking plate 21. The bottom end of the second blocking plate 22, corresponding to the weld position, also has the weld elastic fitting portion 211. The top end of the second blocking plate 22 is thermally connected to the first end face 111, and the second blocking plate 22 is located on the side of the first blocking plate 21 away from the laser entrance port 110. The aforementioned second blocking plate 22 and the first blocking plate 21 may have the same structural configuration. Of course, they may also be different depending on actual needs. In a specific embodiment, the second blocking plate 22 and the first blocking plate 21 have the same structural configuration. In a preferred embodiment, the first blocking plate 21 and the second blocking plate 22 within the same spatter blocking structure 2 are arranged alternately so that the second blocking plate 22 can be used to perform secondary interception of spatter passing through the first blocking plate 21, thereby improving the spatter blocking effect.

[0042] In this technical solution, a first blocking plate 21 and a second blocking plate 22 are simultaneously arranged on the same side of the laser inlet 110. The second blocking plate 22 can be used to intercept the splashes that pass through the first blocking plate 21, thereby improving the blocking effect of the splashes.

[0043] In some embodiments, the thickness of the first blocking plate 21 and the second blocking plate 22 is 0.1 mm to 20 mm, and the appropriate thickness can be selected according to actual needs.

[0044] It is understandable that when the weld elastic fitting portion 211 of the first blocking plate 21 and the second blocking plate 22 respectively comes into contact with the weld reinforcement, gaps will inevitably be generated. Spatter can easily leak out through the gaps. Therefore, by further providing the second blocking plate 22 of the present invention downstream in the spatter direction, this part of the leaked spatter can be intercepted again.

[0045] In some embodiments, the top ends of the first blocking plate 21 and the second blocking plate 22 are slidably connected to the first end face 111 to adjust the distance between them, and the positions of the first blocking plate 21 and the second blocking plate 22 relative to the sealing cover 11 can be locked. For example, positioning blocks are respectively provided on the side of the first blocking plate 21 and the second blocking plate 22 away from the laser inlet 110. A set screw is threaded onto the positioning block. When the set screw is screwed in the direction toward the sealing cover 11, its top end will abut against the sealing cover 11, thereby achieving positioning between the blocking plate and the sealing cover 11. Conversely, when the set screw is screwed in the direction away from the sealing cover 11, its top end will disengage from the sealing cover 11, thereby releasing the positioning between them. The distance between the two blocking plates can be adjusted. Setting the locking structure on the side of the blocking plate away from the laser inlet 110 can reduce the probability of the screw and the positioning block being sintered by high temperature.

[0046] In this technical solution, the distance between the first blocking plate 21 and the second blocking plate 22 can be adjusted, allowing the distance between them to be placed in a more suitable position according to the actual situation, thereby ensuring the interception effect of the spatter blocking structure 2. Generally speaking, the higher the welding power, the larger the distance between the two can be arranged, so as to reduce the impact force of the spatter contacting the blocking plate by a greater distance.

[0047] Specifically, in some embodiments, the first end face 111 of the sealing cover 11 has a limiting slide rail 113 extending toward the side of the workpiece to be welded. The limiting slide rail 113 is located in the radially inner region of the sealing ring 12 and on the same side of the laser entrance 110. There are two limiting slide rails 113, which are parallel to and spaced apart from each other in the length direction of the weld. The top ends of the first blocking plate 21 and the second blocking plate 22 are respectively formed with grooves 212 that surround the limiting slide rail 113. It is understood that, except for the position of the grooves 212, the top end faces of the first blocking plate 21 and the second blocking plate 22 should be in close contact with the first end face 111 to ensure effective heat transfer.

[0048] In this technical solution, a protruding limiting slide rail 113 is provided on the first end face 111 to form a sliding fit with the slide groove 212 on the top of the blocking plate, while also forming a ring-shaped anti-detachment connection. This facilitates the adjustment of the distance between the two blocking plates and also increases the heat transfer area by increasing the mating surface between the two, thereby improving the efficiency of heat transfer from the blocking plate to the sealing cover 11.

[0049] In some embodiments, the distance between the first blocking plate 21 and the second blocking plate 22 within the same spatter blocking structure 2 can be 0.5 mm to 50 mm, and can be adjusted before welding begins according to the characteristics of welding spatter.

[0050] In one specific embodiment, the cross-sections of the slide groove 212 and the limiting slide rail 113 are T-shaped and adapted to each other.

[0051] In some embodiments, the second end face 112 is provided with an external heat dissipation structure (indicated in the figure), and the location of the external heat dissipation structure corresponds to the location of each set of splash blocking structures 2 and is thermally connected to the sealing cover 11. In this way, the heat conducted to the sealing cover 11 can be further dissipated efficiently by the external heat dissipation structure, reducing the heat of the sealing cover 11 and ensuring the structural stability and sealing reliability of the sealing cover 11.

[0052] In some embodiments, the external heat dissipation structure includes heat dissipation fins 31, which are thermally connected to the sealing cover 11. Specifically, the heat dissipation fins 31 may be made of aluminum, with their bottom end face in contact with the sealing cover 11.

[0053] In some embodiments, the heat dissipation fins 31 are provided with a heat pipe structure (not shown in the figure). Specifically, the heat pipe structure includes multiple capillaries (not shown in the figure), each filled with an appropriate amount of phase change heat transfer medium (such as refrigerant, acetone, methanol, etc.). The capillaries are divided into an evaporation section, an adiabatic section, and a condensation section along the direction away from the second end face 112. A capillary core structure is formed on the inner wall of each capillary. In this way, the phase change heat transfer medium can efficiently transfer heat from the sealing cover 11 to the fin end position of the heat dissipation fins 31 and dissipate it, thereby achieving efficient heat transfer and dissipation. This structure does not require external circulation control, is extremely simple in structure, requires no control components, has an extremely low failure rate, and has a low overall support cost. Since it is completely outside the sealing cover 11, there is only an external heat transfer connection between it and the sealing cover 11, without damaging the structure of the sealing cover 11, and therefore it has no adverse effects on the vacuum environment.

[0054] In some embodiments, the aforementioned capillaries are arranged parallel to each other along the length of the heat dissipation fins 31, and each capillary extends in a straight line away from the sealing cover 11.

[0055] In some embodiments, a heat-insulating and anti-sticking layer is formed on the side of the first blocking plate 21 near the laser entrance port 110. Specifically, the heat-insulating and anti-sticking layer can be a high-temperature resistant coating such as a nickel-based high-temperature alloy, with a coating thickness of 10μm to 200μm and a bonding strength between the coating and the first blocking plate 21 of not less than 30 MPa. In addition, the aforementioned heat-insulating and anti-sticking layer can also be provided on the side of the second blocking plate 22 near the laser entrance port 110. Of course, depending on the actual situation, since the second blocking plate 22 does not directly bear the direct impact of a large amount of splashing material, it may not be provided with the aforementioned heat-insulating and anti-sticking layer.

[0056] In this technical solution, by setting a heat-insulating and anti-sticking layer on the side of the first blocking plate 21 near the laser inlet 110, the ablation resistance of the first blocking plate 21 to high-temperature splashes can be significantly improved. This can reduce the difficulty of material selection for the first blocking plate 21 and reduce the material cost. It should be noted that the anti-sticking property of the aforementioned heat-insulating and anti-sticking layer can be achieved by polishing the side of the first blocking plate 21 near the laser inlet 110 to improve its smoothness.

[0057] In some embodiments, at least the first blocking plate 21 has multiple reflective strips (not labeled in the figure) on its side closest to the laser entrance port 110. Multiple reflective strips are also provided on the side wall of the first blocking plate 21 facing the laser entrance port 110. Each reflective strip extends vertically along the height direction. In the illustrated embodiment, the cross-section of each reflective strip is an isosceles triangle. This allows for multi-directional reflection of the splashes, increasing the probability of particle separation and vapor condensation in the splashes, reducing the concentration of splashes at the laser entrance port 110, and reducing power attenuation of the laser beam. In some embodiments, the aforementioned second blocking plate 22 may also be provided with the aforementioned reflective strips, which will not be elaborated further.

[0058] In some embodiments, the bottom end of the weld elastic fitting portion 211 forms a slag-receiving bend 2111, see details below. Figure 3 As shown, the bottom end of the weld elastic fitting part 211 is bent upward toward the side near the laser entrance port 110 to form the aforementioned slag receiving bend 2111, so as to receive the particles (including slag) formed by the spatter that splashes onto the heat insulation and anti-sticking layer within the bend structure, thereby reducing the amount of slag falling back to the weld position and further improving the welding quality.

[0059] See Figure 1 As shown, the aforementioned vacuum cylinder 13 is also provided with a vacuum port 132 that communicates with its internal space. It is controllably connected to an external vacuum component (such as a vacuum pump), thereby ensuring the required vacuum level inside the vacuum chamber 1 during the welding process.

[0060] The specific application should be carried out according to the following steps:

[0061] Step 1: Select a suitable spatter blocking structure 2 based on the welding process parameters and weld reinforcement prediction;

[0062] Step 2: Install the selected splash blocking structure 2 inside the vacuum chamber 1 (that is, on the first end face 111 of the sealing chamber 11).

[0063] Step 3: Place the vacuum chamber 1 on the surface of the workpiece (i.e. the workpiece to be welded), press down to make the bottom flexible sealing material (i.e. the aforementioned sealing ring 12) adhere to the workpiece, and at the same time, the discontinuous structure of each blocking piece (i.e. the aforementioned weld elastic fitting part 211) contacts and adaptively covers the weld excess height.

[0064] Step 4: Start the vacuum pump to evacuate the air, and begin laser welding once the required vacuum level is reached;

[0065] Step 5: During the welding process, the spatter is intercepted by the spatter blocking structure 2 in sequence. The heat carried by the spatter is absorbed by the spatter blocking structure 2 and dissipated to the atmosphere through the sealing cover 11 and heat dissipation fins 31. The heat insulation coating (i.e. the aforementioned heat insulation and anti-sticking layer) further blocks the remaining heat radiation.

[0066] Step 6: Welding complete. Turn off the laser and vacuum pump, and remove the vacuum hood after cooling.

[0067] In one specific embodiment, the welding power is 0.01~200 kW, the welding speed is 0.01~5 m / min, and the resulting weld reinforcement is 0.1~30 mm.

[0068] The technical solution of the present invention will be further described below with reference to embodiments and comparative examples:

[0069] Example 1

[0070] A 50 mm thick high-strength steel plate was selected. Before welding, the oil and oxide film on the surface of the plate were removed with acetone, and the plate was fixed on the welding platform. Local vacuum welding was performed using the local vacuum laser welding device of the present invention, which is equipped with a spatter blocking structure. The bottom edge of the vacuum chamber was provided with a flexible sealing material (i.e., the aforementioned sealing ring 12). Inside the vacuum chamber, an inner layer blocking plate (i.e., the aforementioned first blocking plate 21) and an outer layer blocking plate (i.e., the aforementioned second blocking plate 22) were installed on both sides of the laser light port (i.e., the aforementioned laser entrance port 110). Both layers were made of 0.5 mm thick stainless steel. The bottom of both the inner and outer layers blocking plates were processed into a comb-shaped conformal part (i.e., the aforementioned weld elastic fitting part 211). The width of the comb teeth was 0.5 mm, the gap was 0.3 mm, and the length of the comb teeth was 15 mm. The inner and outer comb teeth are staggered (the gap between the inner comb teeth is directly opposite the solid outer comb teeth), with a 3 mm spacing between the inner and outer layers. The outer layer's blocking plate has a heat-insulating coating on the side facing the flexible sealing material. The vacuum hood is pressed down, causing the bottom sealing material to adhere to the workpiece surface. Simultaneously, the comb-shaped contoured part contacts and naturally bends along the weld reinforcement. The vacuum pump is started, and welding begins once the vacuum reaches 5 Pa. Welding parameters: welding power 15 kW, welding speed 0.8 m / min.

[0071] Technical Effects and Analysis: Through the aforementioned welding process, localized vacuum laser welding of thick stainless steel plates was achieved. The resulting weld surface morphology of the thick stainless steel plate is as follows: Figure 4 As shown in (a), the local vacuum laser welding method of this invention achieves high-quality steel welding with no welding defects on the weld surface, and the vacuum level is maintained at around 10 Pa throughout. After welding, the flexible sealing material has a smooth surface, free of spatter, burns, and signs of thermal aging. The surface temperature of the baffle plate is low, the weld is well-formed, and the surface has a metallic luster without oxidation. After three consecutive welding cycles, the sealing material retains its initial elasticity and does not require replacement.

[0072] Comparative Example 1

[0073] A 50 mm thick high-strength steel plate was selected. Before welding, the surface oil and oxide film were removed with acetone, and the plate was fixed on the welding platform. A conventional vacuum hood was used, i.e., no internal baffles (an improved structure of this invention), with only a flexible sealing material of the same specifications at the bottom. The vacuum pump was started, and welding began after the vacuum level reached 5 Pa. Welding parameters: welding power 15 kW, welding speed 0.8 m / min.

[0074] Technical effects and analysis: Through the aforementioned welding process, the surface morphology of the weld seam in thick stainless steel plates is as follows: Figure 4As shown in (b), although the local vacuum laser welding technology achieved the welding of thick stainless steel plates, the molten pool fluctuated significantly during the process, resulting in severe metal spatter. The vacuum level increased from the initial 5 Pa to 1000 Pa, leading to severe oxidation of the weld surface. The decrease in vacuum level directly confirmed the sealing failure and gas leakage. The leakage allowed residual air to enter the welding zone, causing surface oxidation of the weld. Simultaneously, it disrupted the local vacuum environment's suppression of plasma plume, causing the plume to expand more rapidly. This not only contaminated the protective lens but also further weakened the weld penetration due to laser energy scattering and attenuation. The results indicate that without any obstruction, direct impact from spatter can cause the sealing material to fail in a very short time, making normal welding impossible.

[0075] Comparative Example 2

[0076] A 50 mm thick high-strength steel plate was selected. Before welding, the surface of the plate was cleaned with acetone to remove oil and oxide film, and then the plate was fixed on the welding platform. Inside the vacuum chamber, only a single layer of baffles (0.3 mm thick, stainless steel) was installed on both sides of the light-transmitting opening. The bottom of the baffles had a comb-like profile (same specifications as in Example 1), and the side of the baffles facing the flexible sealing material did not have a heat-insulating coating. Welding parameters: welding power 15 kW, welding speed 0.8 m / min.

[0077] Technical Results and Analysis: During the welding process, the initial vacuum level remained stable at around 10 Pa. As welding progressed, the baffle plate continuously absorbed heat from the spatter, and the temperature gradually increased. After 40 seconds of welding, the vacuum level began to decrease, rising from 10 Pa to 500 Pa. Inspection revealed that the flexible sealing material near the baffle plate showed obvious thermal aging discoloration, localized loss of elasticity, and fine cracks on the surface. Spatter residue adhered to the surface of the baffle plate, but the comb-like structure remained intact. The results indicate that although a single-layer baffle plate can intercept most of the spatter and prevent direct impact, the baffle plate itself becomes a heat source, heating the sealing material through thermal radiation, leading to thermal aging failure and the inability to maintain a stable vacuum level throughout the process.

[0078] Comparative Example 3

[0079] A 50 mm thick high-strength steel plate was selected. Before welding, the oil and oxide film on the surface of the plate were removed with acetone, and the plate was fixed on the welding platform. A double-layer baffle structure (inner layer + outer layer, same specifications as in Example 1) was adopted, with the bottom comb teeth arranged in a staggered manner. The side of the outer baffle facing the flexible sealing material was not provided with a heat insulation coating.

[0080] Technical Results and Analysis: Initially, the double-layer barrier performed better than Comparative Example 2, maintaining a stable vacuum of 10 Pa for approximately 40 seconds. As welding progressed, both the inner and outer barrier layers absorbed heat from the spatter, causing their temperatures to rise synchronously. At 70 seconds, the temperatures of both the inner and outer barrier layers increased. At this point, the vacuum level began to decrease, rising from 10 Pa to 100 Pa. Inspection revealed that although the flexible sealing material was not directly impacted by spatter, it was affected by the combined heat radiation from the inner and outer barrier layers, resulting in a wider thermal aging area compared to Comparative Example 2. The sealing material as a whole hardened and lost its elasticity. The results indicate that while the double-layer barrier improved spatter interception efficiency, it still could not solve the problem of thermal damage to the sealing material caused by heat radiation. Without an insulating coating, the double-layer barrier, due to the increased number of barrier layers and larger heat radiation area, had a more significant thermal impact on the sealing material.

[0081] Comparative Example 4

[0082] Select a 50mm thick high-strength steel plate. Before welding, remove oil and oxide film from the plate surface with acetone and fix the plate on the welding platform. A double-layer baffle structure is adopted. The outer baffle has a heat-insulating coating on the side facing the flexible sealing material (same as in Example 1), but the inner and outer comb teeth are aligned (the gap between the inner comb teeth is directly opposite the gap between the outer comb teeth), and are not misaligned.

[0083] Technical Effects and Analysis: During the welding process, the vacuum level remained stable at 10 Pa throughout, and the temperature of the baffle plate was controlled below 50°C. After welding, the sealing material was found to be intact with no signs of thermal aging. However, upon removal of the baffle plate, it was observed that the outer baffle plate surface was adhered to a large number of fine spatter particles, some of which had penetrated the gaps between the inner comb teeth and directly impacted the outer comb teeth. Although they did not penetrate the outer layer, this indicates that with aligned arrangement, fine particles can pass through the gaps between the two layers along a straight path, resulting in a lower interception efficiency than with staggered arrangement. Microscopic observation showed that the amount of spatter adhering to the outer baffle plate of Comparative Example 4 per unit area was approximately 2.3 times that of Example 1, indicating that the staggered arrangement significantly improved the interception capability of fine particles.

[0084] 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.

[0085] 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 apparatus equipped with a spatter blocking structure, characterized in that, The system includes a vacuum hood (1), which includes a sealing hood body (11). A laser inlet (110) is formed on the sealing hood body (11). The end face of the sealing hood body (11) near the workpiece to be welded is a first end face (111). A sealing ring (12) is provided around the laser inlet (110) on the outer periphery of the first end face (111). A spatter blocking structure (2) is also provided in the area surrounded by the sealing ring (12). At least two sets of the spatter blocking structures (2) are provided. Each set of the spatter blocking structures (2) is spaced apart on both sides of the laser inlet (110) along the weld length direction of the workpiece to be welded, and each set of the spatter blocking structures (2) is connected to the first end face (111).

2. The local vacuum laser welding apparatus according to claim 1, characterized in that, Each of the spatter blocking structures (2) includes a first blocking plate (21) arranged perpendicular to the length direction of the weld. The end of the first blocking plate (21) near the workpiece to be welded is the bottom end. The bottom end of the first blocking plate (21) has a weld elastic fitting part (211) at least in the area corresponding to the weld position.

3. The local vacuum laser welding apparatus according to claim 2, characterized in that, The end of the first blocking plate (21) away from the workpiece to be welded is the top end, and the top end of the first blocking plate (21) is thermally connected to the first end face (111).

4. The local vacuum laser welding apparatus according to claim 2 or 3, characterized in that, Each of the spatter blocking structures (2) further includes a second blocking plate (22) arranged parallel to and spaced apart from the first blocking plate (21). The area at the bottom end of the second blocking plate (22) corresponding to the weld position also has the weld elastic fitting part (211). The top end of the second blocking plate (22) is thermally connected to the first end face (111), and the second blocking plate (22) is located on the side of the first blocking plate (21) away from the laser inlet (110).

5. The local vacuum laser welding apparatus according to claim 4, characterized in that, The top ends of the first blocking plate (21) and the second blocking plate (22) are slidably connected to the first end face (111) so that the distance between them can be adjusted, and the positions of the first blocking plate (21) and the second blocking plate (22) relative to the sealing cover (11) can be locked.

6. The local vacuum laser welding apparatus according to claim 5, characterized in that, The sealing cover (11) has a limiting slide rail (113) extending toward the side of the workpiece to be welded on the first end face (111). On the same side of the laser inlet (110), there are two limiting slide rails (113). The two limiting slide rails (113) are arranged parallel to the length direction of the weld and spaced apart. The top ends of the first blocking plate (21) and the second blocking plate (22) are respectively formed with a groove (212) that surrounds the limiting slide rail (113).

7. The local vacuum laser welding apparatus according to claim 6, characterized in that, The sealing cover (11) has a second end face (112) that is parallel to and opposite to the first end face (111). The second end face (112) is provided with an external heat dissipation structure, and the position of the external heat dissipation structure corresponds to the position of each set of splash blocking structures (2) and is heat-transfer connected to the sealing cover (11).

8. The local vacuum laser welding apparatus according to claim 7, characterized in that, The external heat dissipation structure includes heat dissipation fins (31), which are thermally connected to the sealing cover (11).

9. The local vacuum laser welding apparatus according to claim 8, characterized in that, The heat dissipation fins (31) are equipped with heat pipe structures.

10. The local vacuum laser welding apparatus according to claim 2, characterized in that, At least the first blocking plate (21) has a plurality of reflective strips on the side of the laser inlet (110).

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