Underwater multi-beam coaxial wire feeding machining head protection device and method

Abstract

The invention discloses an underwater multi-beam coaxial wire feeding machining head protection device and method, and belongs to the technical field of underwater laser machining. The device comprises a local dry area creating unit, an optical fiber sealing unit, a wire drawing unit and a wire feeding sealing unit. The local dry area creating unit forms a local dry area underwater through an air curtain ejected from the bottom of the drainage cover; the optical fiber sealing unit adopts a glue injection sealing structure to realize reliable cabin-penetrating sealing of multiple paths of optical fibers in a high-pressure water environment; the wire drawing unit is integrated with a heating coil and can conduct on-line preheating and dehumidification on welding wires. The wire feeding sealing unit achieves dynamic sealing of welding wires through a multi-stage pressing sealing structure. The sealing problem of the optical fiber and the wire feeding channel in underwater coaxial wire feeding machining is solved, real coaxial conveying of the welding wire and the laser beam is achieved, and the quality reliability and the environment adaptability in the machining processes of underwater laser cladding, welding and the like are effectively improved.

Description

TECHNICAL FIELD

[0001] The application relates to the underwater laser processing technical field, in particular to a protection device and method for an underwater multi-beam coaxial wire feeding processing head. BACKGROUND

[0002] In strategic fields such as marine engineering equipment, underwater pipeline construction and nuclear power, there is an urgent need for a technology capable of directly performing high-performance metal component additive manufacturing, welding and repair underwater. The coaxial wire feeding laser processing technology can realize the precise synchronization and intersection of the welding wire and the laser beam, forming a symmetrical and stable cladding area, which has obvious process advantages compared to lateral wire feeding. However, when this technology is applied to underwater environments, it faces severe sealing challenges brought about by the water medium: environmental water can easily enter the device through the wire feeding channel, laser transmission channel and other paths, causing a series of problems such as affecting the state of the welding wire, laser energy attenuation, circuit short circuit, etc. These sealing problems seriously restrict the application and development of coaxial wire feeding technology in underwater environments.

[0003] In view of the increasing demand for underwater application of coaxial wire feeding laser processing technology, there is an urgent need for corresponding sealing structures. The invention patent with the Chinese patent publication number CN115488499A proposes an underwater laser wire filling welding device, which adopts a scheme of separating the wire feeding mechanism from the underwater laser welding sealing body, which achieves miniaturization of the equipment to a certain extent, but does not design the specific sealing structure of the wire feeding channel and the fiber penetration cabin, which cannot guarantee the long-term sealing reliability in high water pressure environments. The invention patent with the Chinese patent publication number CN116352265A provides an L-shaped laser head underwater sealing device, which completely places the laser optical system inside the sealed cabin, which improves the sealing of the laser head, but the drain cover is set outside the sealed cabin, and the welding wire can only be introduced into the drain cover from the side, which makes the wire feeding channel unable to realize true coaxial configuration with the laser beam, limiting its application in underwater coaxial wire feeding processes. SUMMARY

[0004] The purpose of the present application is to provide a protection device and method for an underwater multi-beam coaxial wire feeding processing head to solve the sealing problem of the underwater multi-beam coaxial wire feeding processing head. The sealing problem of underwater wire feeding and optical fiber is solved, a stable local dry processing environment is created, and high reliability, high quality and long service life operation of underwater laser processing are realized.

[0005] Technical solution: In order to achieve the above purpose, the present application adopts the following technical solution:

[0006] The first aspect of this invention provides a protective device for an underwater multi-beam coaxial wire feeding processing head, comprising a local dry zone creation unit, an optical fiber sealing unit, a wire drawing unit, and a wire feeding sealing unit. The local dry zone creation unit includes a laser processing head positioned underwater and a drainage hood surrounding the laser processing head. The drainage hood has a gas inlet and is capable of spraying a gas curtain to the bottom of the drainage hood to form a local dry zone. The optical fiber sealing unit is located at the top cover of the drainage hood and is used to seal the optical fiber passing through the top cover and connected to the laser processing head. The wire feeding sealing unit is installed at the top cover of the drainage hood and is used to dynamically seal the welding wire passing through the wire feeding sealing unit and guide the welding wire into the local dry zone. The wire drawing unit is located inside the top cover of the drainage hood and cooperates with the welding wire to drive the welding wire downwards in a coaxial direction. The wire drawing unit and / or the wire feeding sealing unit are equipped with heating coils for online preheating and dehumidification of the welding wire.

[0007] Furthermore, the local dry zone creation unit includes an optical fiber, a drainage cover top cover, a first connecting bolt, a laser processing head, a one-way valve, a second connecting bolt, a first drainage cover assembly, a second drainage cover assembly, a drainage cover shell, and connecting screws. The optical fiber passes through the optical fiber hole of the drainage cover top cover and is connected to the laser processing head, forming a seal through the optical fiber sealing unit. The drainage cover top cover is fixed to the drainage cover shell by the first connecting bolt. The one-way valve is assembled on the reserved hole on the first drainage cover assembly. The second drainage cover assembly is fixed to the drainage cover shell by the connecting screws. The first drainage cover assembly and the second drainage cover assembly are fixed together by the second connecting bolt, forming a gas circuit between the first drainage cover assembly and the second drainage cover assembly. High-pressure gas enters the drainage cover through the one-way valve and is ejected from the bottom, forming an air curtain at the bottom of the drainage cover, creating a local dry zone for underwater laser printing.

[0008] Furthermore, the optical fiber sealing unit includes an upper sealing plate, a first sealing plug, an upper plate of the adhesive cavity, an adhesive cavity wall, an injection tube, a check valve, and a second sealing plug; the optical fiber passes through the optical fiber hole reserved in the top cover of the drainage cover; the first sealing plug is sleeved on the outer wall of the optical fiber and pressed against the adhesive cavity wall; the adhesive cavity wall is connected to the top cover of the drainage cover by threaded fasteners; the upper plate of the adhesive cavity and the adhesive cavity wall are connected by threaded fasteners; the second sealing plug is sleeved on the optical fiber, and the upper sealing plate is connected to the adhesive cavity wall by threaded fasteners and simultaneously presses the second sealing plug; the injection tube passes through the injection port of the adhesive cavity wall and is connected to the check valve at the rear end.

[0009] Furthermore, the wire drawing unit includes a heating coil, wire feeding wheels, a shaft, a coupling, a motor, and a humidity sensor. The heating coil is fixed to the lower wire feeding sealing connector of the wire feeding sealing unit. The welding wire passes through the center of the coil. When feeding the wire, the coil is energized to dehumidify and preheat the welding wire, ensuring the state of the molten pool during processing and improving processing quality. The wire feeding wheel is fixed to the shaft via a key connection. The shaft is fitted with a bearing and fixed to a protruding support on the top cover of the drainage cover. The coupling connects the shaft and the motor. The motor is fixed to the top cover of the drainage cover. The motor drives the shaft to rotate to transmit torque to the wire feeding wheels. When the two wire feeding wheels rotate, they squeeze and drive the welding wire downward to achieve the wire feeding function. The humidity sensor monitors the surface condition of the welding wire in real time. When the humidity exceeds the calibrated value, wire feeding stops, and the chamber is continuously heated until the humidity meets the processing requirements.

[0010] Furthermore, the wire feeding and sealing unit includes a welding wire, a wire feeding tube, an upper sealing connector, a middle sealing connector, a lower sealing connector, a first rubber sealing ring, a second rubber sealing ring, a first connecting bolt, a second connecting bolt, a first connecting screw, and a second connecting screw. The welding wire passes through the wire feeding tube and is coaxially engaged with the first and second rubber sealing rings respectively by the upper sealing connector. The inner diameter of the two rubber sealing rings is slightly smaller than the diameter of the welding wire to achieve a seal on the welding wire. The wire feeding tube and the upper sealing connector are connected by the first connecting bolt. The first elastic sealing ring is fixed by the pressing action of the upper and middle sealing connectors. The upper and middle sealing connectors are fixed by the first connecting screw. The second rubber sealing ring is fixed by the pressing action of the middle and lower sealing connectors. The middle and lower sealing connectors are fixed by the second connecting bolt. The lower sealing connector is fixed to the top cover of the drainage cover by the second connecting screw.

[0011] A second aspect of the present invention provides a method for protecting an underwater multi-beam coaxial wire feeding head, the method comprising the following steps based on the aforementioned underwater multi-beam coaxial wire feeding head protection device:

[0012] S1: First, connect and fix the first drainage cover assembly and the second drainage cover assembly. Then, install the one-way valve on the reserved mounting hole on the first drainage cover assembly. Next, fit the laser processing head with the drainage cover and fix the whole assembly inside the drainage cover shell.

[0013] S2: Connect one end of the optical fiber to the laser processing head, and pass the other end through the optical fiber passage hole of the top cover of the drainage cover. Then, use bolts to press the top cover of the drainage cover onto the outer shell of the drainage cover. Then, pass the second sealing plug and the optical fiber sealing wall of the optical fiber sealing unit through the optical fiber in sequence. Then, use threaded fasteners to press the cavity wall and the second sealing plug onto the top cover of the drainage cover. Then, fix the upper plate of the cavity to the cavity wall with threaded fasteners. Install the first sealing plug at the wedge-shaped notch of the upper plate of the cavity and press it with the upper sealing pressure plate. After installation, inject glue into the cavity through the glue injection tube. When the pressure in the cavity reaches a certain level, close the check valve to prevent leakage.

[0014] S3: After properly aligning the wire feeding wheel with the shaft, assemble it onto the support of the top cover of the drainage hood. Then, connect the motor to the shaft using a coupling to provide torque for the wire feeding wheel during operation.

[0015] S4: Assemble the upper sealing connector, first rubber sealing ring, middle sealing connector, second rubber sealing ring and lower sealing connector of the wire feeding sealing unit from top to bottom. Then use threaded fasteners to press and fix the upper sealing connector and the middle sealing connector, and the middle sealing connector and the lower sealing connector. Then fix the heating coil in the coil hole of the lower sealing connector with a waterproof plug. Finally, use screws to press the lower sealing connector onto the top cover of the drainage cover.

[0016] S5: The upper sealing connector of the wire feeding tube and the wire feeding sealing unit is fixed by threaded fasteners, and the upper part of the wire feeding tube extends to the water work platform.

[0017] S6: Position the device underwater to be processed, open the one-way valve to introduce gas into the drainage hood to create a local dry area; pass a high-energy laser through the optical fiber, simultaneously energize the heating coil to heat and dehumidify the welding wire, and start the wire drawing mechanism motor to feed the wire downwards to begin the printing process.

[0018] Furthermore, in step S6, the humidity sensor detects the humidity of the welding wire in real time. When the humidity is higher than the set value, the wire feeding is stopped and heating continues until the humidity meets the processing requirements before the wire feeding is resumed.

[0019] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0020] (1) When performing underwater complex trajectory processing, the device of the present invention is not limited by changes in spatial attitude and can achieve high-precision and high-efficiency material transportation.

[0021] (2) The present invention integrates a welding wire preheating system in the wire drawing mechanism. The welding wire is precisely preheated directly by coil heating, which can directly increase the temperature of the welding wire, better form a metallurgical molten pool, avoid the influence of the underwater humid environment, and monitor the status of the welding wire in real time through sensors.

[0022] (3) Based on the sealing requirements of underwater multi-beam laser optical fiber, the present invention ensures the long-term sealing reliability of multi-beam optical fiber in high-pressure water environment through glue injection sealing structure, and also protects the fragile optical fiber from mechanical damage at the introduction point, thus ensuring the stable transmission of laser. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0024] Figure 2 This is a schematic diagram of the local dry area creation unit of the present invention;

[0025] Figure 3 This is a schematic diagram of the optical fiber sealing unit structure of the present invention;

[0026] Figure 4 This is a schematic diagram of the wire drawing unit structure of the present invention;

[0027] Figure 5 This is a schematic diagram of the wire feeding and sealing unit structure of the present invention;

[0028] Reference numerals: 1. Local dry zone creation unit; 101. Optical fiber; 102. Drainage hood top cover; 103. First connecting bolt; 104. Laser processing head; 105. One-way valve; 106. Second connecting bolt; 107. First drainage hood assembly; 108. Second drainage hood assembly; 109. Drainage hood outer shell; 110. Connecting screw; 2. Fiber optic sealing unit; 201, upper sealing pressure plate; 202, first sealing plug; 203, upper plate of glue cavity; 204, glue cavity wall; 205, glue injection tube; 206, check valve; 207, second sealing plug; 3. Wire drawing unit; 301, heating coil; 302, wire feeding wheel; 303, shaft; 304, coupling; 305, motor; 306, humidity sensor; 4. Wire feeding sealing unit; 401, welding wire; 402, wire feeding tube; 403, first connecting bolt; 404, upper sealing connector; 405, first rubber sealing ring; 406, first connecting screw; 407, middle sealing connector; 408, second rubber sealing ring; 409, second connecting bolt; 410, lower sealing connector; 411, second connecting screw. Detailed Implementation

[0029] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. These embodiments are implemented under the premise of the technical solution of the present invention. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0030] like Figure 1As shown, an underwater multi-beam coaxial wire feeding processing head protection device of this embodiment includes a local dry zone creation unit 1, an optical fiber sealing unit 2, a wire drawing unit 3, and a wire feeding sealing unit 4; the local dry zone creation unit 1 is suspended in the underwater processing position; the optical fiber sealing unit 2 is fixed on the drainage cover 102 in the local dry zone creation unit 1; the wire drawing unit 3 is located in the box of the drainage cover 1; the wire feeding sealing unit 4 is connected and fixed to the drainage cover 102 by threaded fasteners, wherein the welding wire 401 is fed downward by the wire drawing unit 3.

[0031] In some embodiments, such as Figure 2 As shown, the local dry area creation unit 1 consists of an optical fiber 101, a drainage cover top cover 102, a first connecting bolt 103, a laser processing head 104, a one-way valve 105, a second connecting bolt 106, a first drainage cover assembly 107, a second drainage cover assembly 108, a drainage cover housing 109, and connecting screws 110. The drainage cover, composed of the first drainage cover assembly 108 and the second drainage cover assembly 109, allows gas to enter through the one-way valve 105 and spray an air curtain from the bottom of the drainage cover to isolate surrounding water and create a dry processing environment. The laser processing head 104 is mounted inside the drainage cover and performs printing within the local dry area. The drainage cover is connected to the drainage cover housing 109 via threaded fasteners. The top of the drainage cover housing 109 is sealed to the drainage cover top cover 102 to prevent internal water leakage.

[0032] like Figure 3 As shown, the fiber optic sealing unit 2 consists of an upper sealing plate 201, a first sealing plug 202, an upper plate of the adhesive cavity 203, an adhesive cavity wall 204, an adhesive injection tube 205, a check valve 206, and a second sealing plug 207. The second sealing plug 207 is installed at the reserved opening of the drain cover top cover 102 after the fiber optic cable 101 passes through its central hole, and is pressed by the adhesive cavity wall 204. The adhesive cavity wall 204 is connected to the drain cover top cover 102 at the bottom and to the upper plate of the adhesive cavity 203 at the top by threaded fasteners. The first sealing plug 201 is also fixed by the upper sealing plate 201 after the fiber optic cable 101 passes through its central hole. The upper sealing plate 201 is fixed to the upper plate of the adhesive cavity 203 by threaded fasteners, and the two are fixed together to form a sealed adhesive cavity inside. One end of the glue injection tube 205 is equipped with a check valve 206, and the other end is connected to the glue cavity. Glue is injected into the glue cavity through the glue injection tube to achieve sealing and protection of the optical fiber. When the pressure in the glue cavity reaches a certain level, the check valve is closed to prevent leakage.

[0033] like Figure 4As shown, the wire drawing unit 3 consists of a heating coil 301, a wire feeding wheel 302, a shaft 303, a coupling 304, a motor 305, and a humidity sensor 306. The heating coil 301 is fixed to the lower sealing connector 410 of the wire feeding sealing unit via a waterproof joint. During wire feeding, it is energized to heat the welding wire, ensuring the surface of the welding wire remains dry. The wire feeding wheel 302 is connected to the shaft 303 via a key and transmits torque. The motor 305 is connected to the shaft 303 via the coupling 304, providing torque for the wire feeding wheel 302 to feed the welding wire downwards. The humidity sensor 306 enables real-time monitoring of the welding wire's condition, providing visualized data for real-time adjustment of operating parameters.

[0034] like Figure 5 As shown, the wire feeding and sealing unit 4 consists of a welding wire 401, a wire feeding tube 402, an upper sealing connector 404, a middle sealing connector 407, a lower sealing connector 410, a first rubber sealing ring 405, a second rubber sealing ring 408, a first connecting bolt 403, a second connecting bolt 409, a first connecting screw 406, and a second connecting screw 411. The upper part of the wire feeding tube 402 extends to the water surface, protecting the welding wire from the water surface working platform to the underwater printing device. The bottom of the wire feeding tube 402 is connected and fixed to the upper sealing connector 404 by a flange structure through the first connecting bolt 403 and the upper sealing connector 404, thereby pressing the first rubber sealing ring 405; the upper sealing connector 404 and the middle sealing connector 407 are fixed by the first connecting screw 403, thereby pressing the first rubber sealing ring 405; the middle sealing connector 407 and the lower sealing connector 410 are fixed by the second connecting bolt 403, thereby pressing the second rubber sealing ring 408; the lower sealing connector 410 is fixed and sealed on the top cover 102 of the drainage cover by the second connecting screw.

[0035] A method for protecting an underwater multi-beam coaxial wire feeding machining head based on the above embodiments includes the following steps:

[0036] Step 1: First, connect and fix the first and second drainage cover assemblies. Then, install the one-way valve into the pre-drilled mounting hole on the first drainage cover assembly. Next, mate the laser processing head with the drainage cover and fix the entire assembly inside the drainage cover housing.

[0037] Step 2: Connect one end of the optical fiber to the laser processing head, and pass the other end through the optical fiber passage hole in the top cover of the drainage cover. Then, use bolts to press the top cover of the drainage cover onto the outer shell of the drainage cover. Next, pass the second sealing plug and the optical fiber sealing wall of the optical fiber sealing unit through the optical fiber in sequence. Then, use threaded fasteners to press the cavity wall and the second sealing plug onto the top cover of the drainage cover. Then, fix the upper plate of the cavity to the cavity wall with threaded fasteners. Install the first sealing plug at the wedge-shaped notch of the upper plate of the cavity and press it with the upper sealing pressure plate. After installation, inject glue into the cavity through the glue injection tube. When the pressure in the cavity reaches a certain level, close the check valve to prevent leakage.

[0038] Step 3: After properly aligning the wire feeding wheel with the shaft, assemble it onto the support of the top cover of the drainage hood. Then, connect the motor to the shaft using a coupling to provide torque for the wire feeding wheel during operation.

[0039] Step 4: Assemble the upper sealing connector, first rubber sealing ring, middle sealing connector, second rubber sealing ring, and lower sealing connector of the wire feeding sealing unit from top to bottom. Then, use threaded fasteners to press and fix the upper sealing connector to the middle sealing connector and the middle sealing connector to the lower sealing connector. Next, fix the heating coil in the coil hole of the lower sealing connector with a waterproof plug. Finally, use screws to press the lower sealing connector onto the top cover of the drainage cover.

[0040] Step 5: The upper sealing connector of the wire feeding tube and the wire feeding sealing unit is connected and fixed by threaded fasteners, and the upper part of the wire feeding tube extends to the water work platform.

[0041] Step Six: Position the device underwater at the processing location, open the one-way valve to introduce gas into the drainage hood to create a localized dry area; transmit a high-energy laser through the optical fiber, simultaneously energize the heating coil to heat and dehumidify the welding wire, and start the wire drawing mechanism motor to feed the wire downwards, commencing the printing process. Alternatively, a humidity sensor can be used to monitor the welding wire humidity in real time during this step. When the humidity exceeds the set value, wire feeding is stopped, and heating continues until the humidity meets the processing requirements before resuming wire feeding.

Claims

1. A protective device for an underwater multi-beam coaxial wire feeding machining head, characterized in that, The system includes a localized dry zone creation unit (1), an optical fiber sealing unit (2), a wire drawing unit (3), and a wire feeding sealing unit (4). The localized dry zone creation unit (1) includes a laser processing head (104) located at the underwater processing position and a drainage cover surrounding the laser processing head (104). The drainage cover has a gas inlet and can spray a gas curtain to the bottom of the drainage cover to form a localized dry zone. The optical fiber sealing unit (2) is located at the top cover (102) of the drainage cover and is used to seal the laser processing head (104) that passes through the top cover (102) of the drainage cover. The fiber optic cable (101) is sealed through the chamber; the wire feeding sealing unit (4) is installed at the top cover (102) of the drainage cover, and is used to dynamically seal the welding wire passing through the wire feeding sealing unit (4) and guide the welding wire (401) into the local dry area; the wire drawing unit (3) is set inside the top cover (102) of the drainage cover and cooperates with the welding wire (401), and is used to drive the welding wire (401) to feed downward along the coaxial direction; the wire drawing unit (3) and / or the wire feeding sealing unit (4) are provided with heating coils (301) for online preheating and dehumidification of the welding wire.

2. The underwater multi-beam coaxial wire feeding head protection device according to claim 1, characterized in that, The drainage cover includes a one-way valve (105), a first drainage cover assembly (107), and a second drainage cover assembly (108). The first drainage cover assembly (107) and the second drainage cover assembly (108) are connected to form a gas circuit. Gas enters the gas circuit through the one-way valve (105) and is ejected from the bottom of the drainage cover, forming an air curtain at the bottom of the drainage cover to isolate the surrounding water.

3. The underwater multi-beam coaxial wire feeding head protection device according to claim 1, characterized in that, The fiber optic sealing unit (2) includes an upper sealing plate (201), a first sealing plug (202), an upper plate of the glue cavity (203), a glue cavity wall (204), a glue injection tube (205), a check valve (206), and a second sealing plug (207). The second sealing plug (207) is formed by an optical fiber (101) passing through its central hole and being pressed by the glue cavity wall (204). The glue cavity wall (204) is connected to the top cover of the drainage cover (102) at the bottom and to the upper plate of the glue cavity (203) at the top by threaded fasteners. The first sealing plug (201) is also formed by an optical fiber (101) passing through its central hole and being fixed by the upper sealing plate (201). The upper sealing plate (201) is connected and fixed to the upper plate of the glue cavity (203) by threaded fasteners.

4. The underwater multi-beam coaxial wire feeding head protection device according to claim 1, characterized in that, The wire feeding sealing unit (4) includes a welding wire (401), a wire feeding tube (402), an upper sealing connector (404), a middle sealing connector (407), a lower sealing connector (410), a first rubber sealing ring (405), a second rubber sealing ring (408), a third connecting bolt (403), a fourth connecting bolt (409), a first connecting screw (406), and a second connecting screw (411); the upper part of the wire feeding tube (402) extends to the water, and the bottom is connected to the upper sealing unit (404) by the third connecting bolt (403). The sealing connector (404) is connected and fixed; the upper sealing connector (404) and the middle sealing connector (407) are fixed by the first connecting screw (403) and the first rubber sealing ring (405) is pressed; the middle sealing connector (407) and the lower sealing connector (410) are fixed by the fourth connecting bolt (409) and the second rubber sealing ring (408) is pressed; the lower sealing connector (410) is fixed on the top cover (102) of the drainage cover by the second connecting screw.

5. The underwater multi-beam coaxial wire feeding head protection device according to claim 4, characterized in that, The wire drawing unit (3) includes a heating coil (301), a wire feeding wheel (302), a shaft (303), a coupling (304), a motor (305), and a humidity sensor (306). The heating coil (301) is fixed to the lower sealing connector (410) of the wire feeding sealing unit through a waterproof joint. The wire feeding wheel (302) is connected to the shaft (303) by a key. The motor (305) is connected to the shaft (303) through the coupling (304) to provide the working torque required for the wire feeding wheel (302). The humidity sensor (306) is used to monitor the status of the welding wire in real time.

6. A method for protecting an underwater multi-beam coaxial wire feeding machining head, implemented using the underwater multi-beam coaxial wire feeding machining head protection device as described in any one of claims 1-5, comprising the following steps: S1: First, connect and fix the first drainage cover assembly and the second drainage cover assembly. Then, install the one-way valve on the reserved mounting hole on the first drainage cover assembly. Next, fit the laser processing head with the drainage cover and fix the whole assembly inside the drainage cover shell. S2: Connect one end of the optical fiber to the laser processing head, and pass the other end through the optical fiber passage hole of the top cover of the drainage cover. Then use bolts to press the top cover of the drainage cover onto the outer shell of the drainage cover. Then pass the second sealing plug and the optical fiber sealing wall of the optical fiber sealing unit through the optical fiber in sequence. Then use threaded fasteners to press the cavity wall and the second sealing plug onto the top cover of the drainage cover. Then fix the cavity upper plate to the cavity wall with threaded fasteners. Install the first sealing plug at the wedge-shaped notch of the cavity upper plate and press it with the upper sealing pressure plate. After installation, inject glue into the cavity through the glue injection tube. When the pressure in the cavity reaches a certain level, close the check valve to prevent leakage. S3: After properly aligning the wire feeding wheel with the shaft, assemble it onto the support of the top cover of the drainage hood. Then, connect the motor to the shaft using a coupling to provide torque for the wire feeding wheel during operation. S4: Complete the assembly of the upper sealing connector, first rubber sealing ring, middle sealing connector, second rubber sealing ring and lower sealing connector of the wire feeding sealing unit from top to bottom. Then use threaded fasteners to press and fix the upper sealing connector and the middle sealing connector, and the middle sealing connector and the lower sealing connector. Then fix the heating coil in the coil hole of the lower sealing connector with a waterproof plug. Finally, use screws to press the lower sealing connector onto the top cover of the drain cover. S5: The upper sealing connector of the wire feeding tube and the wire feeding sealing unit is connected and fixed by threaded fasteners, and the upper part of the wire feeding tube extends to the water work platform. S6: Position the device underwater to be processed, open the one-way valve to introduce gas into the drainage hood to create a local dry area; pass a high-energy laser through the optical fiber, simultaneously energize the heating coil to heat and dehumidify the welding wire, and start the wire drawing mechanism motor to feed the wire downwards to begin the printing process.

7. The underwater multi-beam coaxial wire feeding head protection device according to claim 6, characterized in that, In step S6, the humidity sensor detects the humidity of the welding wire in real time. When the humidity is higher than the set value, the wire feeding is stopped and heating continues until the humidity meets the processing requirements before the wire feeding is resumed.

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