A fluid-driven cyclone annular liquid mist and negative pressure smoke removal synergistic pulse laser processing system and method

Abstract

The application discloses a kind of fluid drive cyclone annular liquid mist and negative pressure smoke removal synergic pulse laser processing system and method, belong to pulse laser processing technical field.System includes pulse laser processing module, coaxial cyclone nozzle, gas supply system, processing liquid supply and recovery system, open smoke hood, negative pressure suction system and mobile platform.Pressurized processing liquid enters nozzle liquid cavity by tangential liquid inlet structure, drives helical blade rotor supported by waterproof bearing to rotate, and is approximately sprayed along axial direction by continuous annular slit;Compressed air is coaxially output through central light gas channel, and hollow annular liquid mist for pulse laser to pass through is formed by rotating liquid flow.Workpiece and smoke hood move synchronously with mobile platform, and circumferential multi-point suction sends smoke dust, fine liquid mist and particles into gas-liquid separation and filtration device, and recycled processing liquid is returned to liquid storage tank by liquid return pump.The system can be used for cutting, punching, etching, grooving and surface material removal.

Description

Technical Field

[0001] This invention relates to the fields of pulsed laser processing, fluid atomization, and processing fume control. Specifically, it relates to a pulsed laser processing system and method that utilizes processing fluid to drive a rotatable helical blade assembly to form an annular swirling liquid mist, uses central compressed air to stabilize the hollow region of the liquid mist, and combines open circumferential multi-point negative pressure suction and processing fluid recovery. Background Technology

[0002] Pulsed lasers are characterized by short processing time, high peak power, and ease of precise positioning. They can be used for cutting, drilling, etching, grooving, and surface material removal in metals, ceramics, glass, semiconductors, polymers, printed circuit boards, and fiber-reinforced composites. During processing, pulsed lasers generate rapid heating, melting, vaporization, or ablation in localized areas, accompanied by fumes, fine particles, molten spatter, and thermally affected materials.

[0003] Gas-assisted cooling can remove some ablation products, but its cooling capacity is limited. Liquid jets or ordinary water mist can enhance heat exchange and scouring, but solid liquid jets or irregular droplets can easily enter the laser propagation path, causing scattering, absorption, or contamination of optical components. Existing coaxial nozzles typically use fixed flow guiding structures to form swirling flow, making it difficult to simultaneously ensure a central optical path, stable formation of swirling liquid mist, nozzle maintainability, and dust and liquid mist recovery.

[0004] Furthermore, unilateral suction can easily lead to uneven distribution of the captured airflow around the processing area; closed or semi-closed processing cavities can restrict workpiece clamping and platform movement. Directly discharging the captured liquid mist as waste liquid will also increase processing fluid consumption. Therefore, a processing system suitable for a fixed pulsed laser processing head and a moving workpiece platform is needed, which can stably distribute the liquid mist around the laser axis and perform circumferential suction and recovery of fumes, fine liquid mist, and particles under open conditions.

[0005] Existing technologies also suffer from problems such as difficulty in disassembling the internal structure of the nozzle, susceptibility of the swirling component to wobbling under liquid flow impact, and difficulty in adapting the outlet gap to different processing conditions. To improve the feasibility and ease of maintenance of the system, it is necessary to comprehensively design the rotor support, modular assembly and disassembly, gas-liquid channel isolation, and outlet adjustment structure. Summary of the Invention

[0006] The purpose of this invention is to provide a pulsed laser processing system and method that combines fluid-driven swirling annular liquid mist with negative pressure smoke removal, in order to solve the problems of easy entry of droplets into the central optical path during liquid-assisted processing, unstable swirling state of ordinary spray, difficulty in uniformly capturing processing dust and liquid mist, and inconvenience in nozzle maintenance and processing fluid recovery.

[0007] To achieve the above objectives, the present invention provides a pulsed laser processing system, comprising a fixedly mounted pulsed laser processing module, a coaxial vortex nozzle mounted below the pulsed laser processing head, a compressed air supply system, a processing fluid supply and recovery system, an open fume hood, a gas-liquid separation and filtration device, a negative pressure pump, and a moving platform. The workpiece and the open fume hood are mounted together on the moving platform, and the moving platform drives both to move synchronously relative to the fixed pulsed laser processing head and the coaxial vortex nozzle along a preset processing trajectory.

[0008] The coaxial vortex nozzle includes a nozzle cavity, a hollow cylindrical support, a rotor assembly, and a nozzle cover. The hollow cylindrical support, as an independent metal component, is coaxially and detachably mounted to the nozzle cavity via a flange bolt structure with a sealing ring. A central phosgene channel is formed inside the hollow cylindrical support, along which the focused pulsed laser beam and compressed air propagate towards the workpiece; an annular liquid cavity is formed between the nozzle cavity and the hollow cylindrical support.

[0009] The rotor assembly includes an annular hub and multiple helical blades integrally machined with the annular hub. The annular hub and a waterproof bearing are connected by an interference fit for radial positioning of the rotor assembly. The waterproof bearing is located at the center of the axial length of the helical blades, ensuring a consistent axial distance from the waterproof bearing to both ends of the helical blades. After the processing fluid enters the annular liquid chamber, it acts on the helical blades, causing the rotor assembly to rotate freely around the nozzle axis. The rotor assembly can be completely removed from the nozzle body for cleaning, inspection, or replacement with rotor assemblies having different numbers of blades and helical angles.

[0010] The nozzle cavity has an annular liquid distribution chamber or liquid distribution manifold as an independent component on its outer periphery. The liquid distribution assembly is detachably installed in the nozzle cavity via a flange bolt structure with a sealing ring, and is supplied with liquid by the main liquid supply pipe. The liquid distribution assembly is connected to at least two circumferentially spaced inlets with the same tangential direction, so that the processing fluid gains an initial circumferential velocity when entering the annular liquid cavity, and further drives the rotor assembly to rotate.

[0011] The nozzle cap is detachably installed at the lower end of the nozzle cavity via threads, and a sealing ring and anti-loosening structure are provided at the threaded connection. A continuous annular slit outlet is formed between the inner wall of the nozzle cap's outlet and the outer wall of the hollow cylindrical support. Various nozzle caps with different outlet inner diameters can be configured, and the width of the annular slit can be adjusted in stages by changing the nozzle cap; the fitting profile and installation position of each nozzle cap remain consistent except for the outlet inner diameter. The processing fluid is ejected downwards from the continuous annular slit outlet, approximately along the nozzle axis.

[0012] The coaxial swirl nozzle has an independent air inlet on its sidewall, located above the annular liquid chamber, and directly connected to the central phosgene channel via a radial air passage that does not pass through the annular liquid chamber. Ordinary compressed air is output downward along the central phosgene channel, forming aerodynamic support and isolation for the inner boundary of the rotating machining fluid; the central compressed air is the necessary airflow to stably form the hollow region, and its pressure and flow rate are adjustable, but not limited to specific values.

[0013] The open-type fume hood has an open top that surrounds the entire perimeter of the workpiece, and multiple suction ports are arranged around its circumference. Each suction port is connected via a short branch pipe to a manifold fixed to the outer perimeter wall of the hood. The manifold is connected to a fixedly installed gas-liquid separation and filtration device via a flexible negative pressure hose or cable chain. The negative pressure pump is located downstream of the gas-liquid separation and filtration device, ensuring that smoke, fine liquid mist, and particles are separated and filtered before the gas phase enters the negative pressure pump.

[0014] The gas-liquid separation and filtration device features an integrated liquid collection chamber at its bottom. The fine liquid mist captured by the open fume hood is separated and filtered before being collected in this integrated chamber. A separate return pump then pumps the mist back to the storage tank via a return pipeline, forming a processing fluid recovery cycle for the captured liquid mist. The system operates on the premise that the processing fluid primarily forms a fine mist that can be carried by the negative pressure airflow, with minimal liquid accumulation inside the hood; it does not claim to achieve complete recovery of all ejected processing fluid.

[0015] This invention also provides a pulsed laser processing method using the above-described system, comprising workpiece and fume hood positioning, negative pressure suction, central gas supply, processing fluid supply, annular swirling liquid mist formation, pulsed laser processing, moving platform trajectory movement, fume and liquid mist collection, gas-liquid separation and filtration, and processing fluid recovery. Each module is primarily controlled independently and manually, with pulsed laser parameters and moving platform trajectory set separately by corresponding control devices. Beneficial effects

[0016] Compared to conventional solid spraying or single-gas assistance, this invention utilizes a tangential liquid inlet structure and a rotatable helical blade assembly driven by the processing fluid to impart circumferential velocity to the processing fluid, and uses central compressed air to stabilize the hollow region, enabling the liquid mist to be distributed around the laser propagation axis, which helps to reduce the interference of the processing fluid on the central optical path.

[0017] The continuous annular slit outlet allows for continuous circumferential output of the processing fluid; by replacing nozzle caps with different outlet inner diameters, the outlet gap can be adjusted in stages without altering the main nozzle structure. A single waterproof bearing provides stable support for the rotor assembly through an interference fit. Simultaneously, the symmetrical arrangement of the bearings relative to both ends of the helical blades ensures coaxiality during rotor rotation, reducing rotational runout, improving stability during swirling liquid mist formation, and simplifying the internal structure of the nozzle for easier manufacturing and maintenance.

[0018] The open-type fume hood moves synchronously with the workpiece, and its circumferential multi-point suction can capture fumes, fine liquid mist, and particles from different directions within the processing area. A gas-liquid separation and filtration device is located upstream of the negative pressure pump, helping to reduce the amount of liquid and particles entering the pump. The captured liquid mist is returned to the storage tank via a return pump, reducing the direct discharge of processing fluid.

[0019] This invention does not rely on unified automatic linkage control; each module can start and stop independently, which facilitates modular modification of existing pulsed laser equipment and is applicable to cutting, drilling, etching, grooving, and surface material removal using nanosecond, picosecond, or femtosecond pulsed lasers. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the pulsed laser processing system of the present invention.

[0021] Figure 2 This is a schematic cross-sectional view of the coaxial swirling nozzle of the present invention.

[0022] Figure 3 This is a schematic diagram of the flow field of the pulsed laser beam and the hollow annular swirling liquid mist acting on the workpiece according to the present invention.

[0023] Figure 4 This is a schematic diagram of the exploded structure of the coaxial swirling nozzle of the present invention.

[0024] Reference numerals: 1.1—Pulsed laser; 1.2—Focusing lens; 1.3—Reflector; 1.4—Concave lens; 1.5—Convex lens; 2—Coaxial vortex nozzle module; 2.1—Gas chamber; 2.2—Gas inlet; 2.3—Helical blade; 2.4—Waterproof bearing; 2.5—Liquid inlet; 2.6—Liquid chamber; 3.1—Reservoir; 3.2—Hydraulic pump; 3.3—Pressure regulator; 3.4—Pressure sensor; 4.1—Pressure... 4.1 Force sensor; 5.2 Pressure regulating valve; 4.3 Air compressor; 5.1 Gas-liquid separation and filtration device; 5.2 Negative pressure pump; 5.3 Integrated liquid collection chamber; 6.1 Nozzle body (base); 6.2 O-ring seal; 6.3 Rotor assembly; 6.4 O-ring seal; 6.5 Nozzle cover; 7 Open fume hood; 8 Workpiece; 9 Moving platform; 10.1 Laser beam; 10.2 Annular swirling liquid mist. Detailed Implementation

[0025] The structure and working process of the present invention will be described below with reference to the accompanying drawings of the original specification. The drawings retain their original content; the structures in the drawings are used to illustrate the main components and their interrelationships and are not drawn to scale. Branch pipes, return pumps, axial spacers, and connecting fasteners not shown in the drawings can be configured according to the following description. The described embodiments are used to illustrate the technical solution of the present invention and are not intended to limit the scope of protection.

[0026] like Figure 1 As shown, the pulsed laser processing module includes a pulsed laser 1.1, a focusing lens 1.2, a reflecting mirror 1.3, a concave lens 1.4, and a convex lens 1.5. The focusing optical element is located inside the laser processing head above the coaxial vortex nozzle module 2. The focused laser beam passes through the central channel of the coaxial vortex nozzle module 2 and then acts on the workpiece 8. The pulsed laser 1.1 can be a nanosecond, picosecond, or femtosecond pulsed laser.

[0027] The pulsed laser processing head and the coaxial vortex nozzle module 2 are fixedly mounted; the workpiece 8 and the open fume hood 7 are mounted together on the moving platform 9 and move synchronously with the moving platform 9 along the preset processing trajectory. The laser focus can be set on the surface of the workpiece 8 or inside the workpiece 8, and the lower end of the coaxial vortex nozzle module 2 maintains an adjustable non-contact working distance from the workpiece 8.

[0028] like Figure 2 and Figure 4 As shown, the coaxial swirl nozzle module 2 includes a nozzle body 6.1, O-rings 6.2 and 6.4, a rotor assembly 6.3, and a nozzle cover 6.5. A hollow cylindrical support is coaxially mounted inside the nozzle body 6.1. The hollow cylindrical support is detachably connected to the cavity with the nozzle through a flange bolt structure with a sealing ring, forming a central phosgene channel inside. The nozzle body 6.1 and the hollow cylindrical support are, in principle, made of corrosion-resistant metal materials.

[0029] Preferably, two waterproof bearings 2.4 are spaced axially around the outer periphery of the hollow cylindrical support body, while a single waterproof bearing 2.4 is also placed around the outer periphery of the hollow cylindrical support body. The waterproof bearings 2.4 are connected to the annular hub in the rotor assembly 6.3 using an interference fit, ensuring a stable radial positioning relationship between the waterproof bearings and the rotor assembly. The waterproof bearings 2.4 are installed in the central region of the axial length of the helical blade 2.3, ensuring that the distances from both sides of the bearing to the ends of the helical blade are essentially the same. This reduces sway caused by uneven force during rotor rotation and improves the coaxiality and stability of the helical blade during rotation. The rotor assembly 6.3 is rotatably mounted on the outer periphery of the hollow cylindrical support body via the waterproof bearings 2.4. The processing fluid acts on the helical blade 2.3, driving the rotor assembly to rotate around the nozzle axis.

[0030] The rotor assembly 6.3 includes an annular hub and multiple helical blades 2.3 integrally machined with the annular hub. These blades can be made of corrosion-resistant metal or water-resistant, wear-resistant polymer materials. The number and helix angle of the helical blades 2.3 can be selected according to the liquid supply conditions and are not limited to the number shown in the diagram. After unscrewing the nozzle cap 6.5, the rotor assembly 6.3, the waterproof bearing 2.4, and the axial spacer sleeve can be removed as a whole or sequentially for cleaning, inspection, or replacement.

[0031] The main liquid supply pipe is connected to an annular liquid distribution chamber or liquid distribution manifold that is detachably set on the outer periphery of the nozzle body 6.1. The liquid distribution assembly is installed on the nozzle body 6.1 through a flange bolt structure with a sealing ring, and supplies liquid to two or more tangential liquid inlets 2.5 that are spaced apart along the circumference. Figure 2 Only one liquid inlet 2.5 is shown; the remaining tangential liquid inlets can be evenly arranged circumferentially. When the processing fluid enters the liquid cavity 2.6 through the tangential liquid inlet 2.5, it gains an initial circumferential velocity, which acts on the spiral blades 2.3, driving the rotor assembly 6.3 to rotate around the nozzle axis.

[0032] The nozzle cap 6.5 is threadedly installed at the lower end of the nozzle body 6.1, and an O-ring 6.4, a lock nut, a locking screw, or an anti-loosening washer are provided at the threaded connection. A continuous annular slit is formed between the inner wall of the nozzle cap 6.5 outlet and the outer wall of the hollow cylindrical support body. By replacing nozzle caps 6.5 with different outlet inner diameters, the width of the annular slit can be adjusted in stages; the processing fluid is generally output downward along the nozzle axis at the slit outlet, while retaining the circumferential velocity component imparted by the rotor assembly.

[0033] The air inlet 2.2 is located on the side wall of the coaxial swirling nozzle module 2 and above the liquid cavity 2.6. The air inlet 2.2 is directly connected to the central phosgene channel of the hollow cylindrical support through a radial air passage, which does not pass through the liquid cavity 2.6. Ordinary compressed air output from the air compressor 4.3 enters the central phosgene channel after being regulated by the pressure regulating valve 4.2 and the pressure sensor 4.1; the pressure and flow rate of the compressed air are adjustable, but this application does not fabricate specific values.

[0034] The processing fluid supply system includes a storage tank 3.1, a hydraulic pump 3.2, a pressure regulating valve 3.3, and a pressure sensor 3.4, and a filter can be installed on the supply line. The processing fluid can be deionized water, coolant, or other water-based processing fluid. The hydraulic pump 3.2 delivers the processing fluid from the storage tank 3.1 to the distribution assembly, and then feeds it into the liquid chamber 2.6 through multiple tangential liquid inlets 2.5.

[0035] The processing fluid drives the rotor assembly 6.3 to rotate and is ejected approximately downwards through a continuous annular slit; simultaneously, central compressed air is output downwards along the central phosgene channel, forming aerodynamic support and isolation for the inner side of the rotating fluid flow. After leaving the outlet, the processing fluid is broken up and formed under the combined action of the circumferential velocity component, the central airflow, and the surrounding airflow. Figure 3 The central hollow annular swirling liquid mist 10.2 is shown. The pulsed laser beam 10.1 is located inside the central airflow and acts on the workpiece 8 through the hollow region.

[0036] The open-type fumigation hood 7 has an open top and surrounds the entire periphery of the workpiece 8, with multiple suction ports arranged around the circumference of the hood. Each suction port is connected to a ring-shaped manifold or main gas collection pipe fixed to the outer periphery of the hood via a short branch pipe, and then connected to a fixed gas-liquid separation and filtration device 5.1 via a flexible negative pressure hose or cable chain. Figure 1 Only one suction pipe can be shown, while the remaining suction ports are arranged around the circumference of the hood to improve the uniformity of smoke and liquid mist collection.

[0037] The negative pressure pump 5.2 is located downstream of the gas-liquid separation and filtration device 5.1. The bottom of the gas-liquid separation and filtration device 5.1 is equipped with an integrated liquid collection chamber 5.3. The smoke, dust, fine liquid mist and particles carried by the suction gas flow are first separated and filtered. The filtered gas phase enters the negative pressure pump 5.2. The separated and filtered processing liquid flows into the integrated liquid collection chamber 5.3 and is then transported back to the storage tank 3.1 by a separately set return pump. Figure 1 This diagram only illustrates the main system connections. The return pump and return pipeline can be arranged between the gas-liquid separation and filtration device 5.1 and the storage tank 3.1.

[0038] Before processing, the workpiece 8 is fixed on the moving platform 9, and the open fume hood 7 moves with the workpiece 8 along with the platform. The pulsed laser parameters, focus position, and platform trajectory are set according to the task of cutting, drilling, etching, grooving, or surface material removal. Then, the negative pressure pump 5.2, air compressor 4.3, and hydraulic pump 3.2 are started sequentially to establish the circumferential suction airflow, central compressed air, and annular swirling liquid mist 10.2. Finally, the pulsed laser 1.1 and the moving platform 9 are started.

[0039] During pulsed laser processing, a focused laser beam 10.1 passes through the central hollow region and acts on the workpiece 8. An annular swirling liquid mist 10.2 is distributed around the processing area, cooling and rinsing the processing area and its surroundings. An open fume hood 7 captures smoke, dust, and fine liquid mist and particles that can be carried by the airflow through multiple circumferential suction ports. The captured liquid mist is returned to the storage tank 3.1 via gas-liquid separation, filtration, and a return pump.

[0040] At the end of processing, first stop the pulsed laser output and the processing movement of the moving platform 9, then stop the hydraulic pump 3.2. Maintain central compressed air to purge the central phosgene channel and nozzle outlet to reduce the possibility of residual processing fluid entering the optical path or depositing inside the nozzle; subsequently, stop the air compressor 4.3 and the negative pressure pump 5.2. Each module is primarily controlled independently and manually; automatic linkage by a unified control system is not required.

[0041] This invention can be applied to workpieces made of metals, ceramics, glass, semiconductors, polymers, printed circuit boards, and fiber-reinforced composite materials. For different materials and pulsed laser types, the annular swirling liquid mist 10.2 can be adapted to the corresponding processing range by replacing the rotor assembly 6.3, the nozzle cover 6.5, and adjusting the liquid and gas supply states. Equivalent substitutions made to the connection method, liquid distribution form, flexible piping, and anti-loosening structure without departing from the basic concept of this invention should all fall within the protection scope of this invention.

Claims

1. A pulsed laser processing system that combines fluid-driven swirling annular liquid mist with negative pressure fume removal, comprising a pulsed laser processing module, a gas supply system, a processing fluid supply and recovery system, a negative pressure suction system, and a moving platform for carrying the workpiece, characterized in that: The pulsed laser processing module includes a fixedly mounted pulsed laser processing head and a coaxial vortex nozzle detachably mounted below the pulsed laser processing head. The coaxial vortex nozzle includes a nozzle cavity, a hollow cylindrical support, a rotor assembly, and a nozzle cover. The hollow cylindrical support is coaxially mounted inside the nozzle cavity, forming a central phosgene channel for the focused pulsed laser beam and compressed air to pass through. An annular liquid cavity is formed between the nozzle cavity and the hollow cylindrical support. The rotor assembly includes an annular hub and multiple helical blades connected to the annular hub. The annular hub is rotatably mounted on the outer periphery of the hollow cylindrical support via a waterproof bearing. The nozzle cavity has at least two tangential inlets distributed circumferentially and communicating with the annular liquid cavity. The processing fluid enters the annular liquid cavity through the tangential inlets and drives the nozzle. The rotor assembly rotates around the nozzle axis; the nozzle cover is installed at the lower end of the nozzle cavity, and a continuous annular slit outlet is formed between the inner wall of the nozzle cover outlet and the outer wall of the hollow cylindrical support body; the coaxial vortex nozzle is provided with an independent air inlet, which is connected to the central phosgene channel through a radial air passage, so that compressed air is output along the central phosgene channel and forms a centrally hollow annular vortex liquid mist together with the rotating processing fluid ejected from the continuous annular slit outlet; the negative pressure suction system includes an open-top fumigation hood, a gas-liquid separation filter assembly, and a negative pressure pump located downstream of the gas-liquid separation filter assembly; the open-top fumigation hood surrounds the workpiece and has multiple suction ports arranged circumferentially; the workpiece and the open-top fumigation hood are installed together on a moving platform and move with the moving platform relative to the fixed laser processing head.

2. The pulsed laser processing system according to claim 1, characterized in that: The processing fluid supply and recovery system includes a storage tank, a hydraulic pump, a main supply pipe, a liquid distribution assembly, a return pump, and a return pipeline. The liquid distribution assembly is connected to the main supply pipe and distributes the processing fluid evenly to multiple tangential inlets. The bottom of the gas-liquid separation and filtration assembly is provided with an integrated liquid collection chamber. The captured liquid mist enters the integrated liquid collection chamber after separation and filtration, and is returned to the storage tank by the return pump.

3. The pulsed laser processing system according to claim 2, characterized in that: The liquid distribution assembly is an annular liquid distribution chamber or a liquid distribution manifold, and is detachably installed on the outer periphery of the nozzle cavity via a flange bolt structure; a sealing structure is provided at the flange connection position to achieve a sealed connection of the liquid supply channel.

4. The pulsed laser processing system according to claim 1, characterized in that: The waterproof bearing is mounted on the outer periphery of the hollow cylindrical support body and is connected to the annular hub by an interference fit. The waterproof bearing is located in the middle region of the axial length of the spiral blade, so that the distance from both sides of the bearing to the end of the spiral blade is basically the same, thereby improving the coaxial stability of the rotor during rotation.

5. The pulsed laser processing system according to claim 1 or 4, characterized in that: The annular hub and the helical blades are integrally machined; the rotor assembly can be removed as a whole after the nozzle cover is removed, and the swirling state of the processing fluid can be adjusted by replacing rotor assemblies with different numbers of blades and / or different helical angles.

6. The pulsed laser processing system according to claim 1, characterized in that: The hollow cylindrical support is installed in the nozzle cavity via a flange bolt structure with a sealing ring; the coaxial swirling nozzle is installed in the pulsed laser processing head via a connecting flange, and the connecting flange is provided with a coaxial positioning stop and / or positioning pin to ensure that the nozzle is coaxial with the laser axis.

7. The pulsed laser processing system according to claim 1, characterized in that: The nozzle cover is installed at the lower end of the nozzle cavity via a threaded connection; a sealing ring and at least one of a locking nut, a locking screw, or an anti-loosening washer are provided at the threaded connection; the outlet size of the continuous annular slit is adjusted by replacing the nozzle cover with a different outlet size.

8. The pulsed laser processing system according to claim 1, characterized in that: The air supply system is a compressed air supply system with adjustable pressure and flow rate; the independent air inlet is located on the side wall of the coaxial swirl nozzle and is directly connected to the central phosgene channel through a radial air passage that does not pass through the annular liquid cavity.

9. The pulsed laser processing system according to claim 1, characterized in that: The open-type fumigation hood is provided with an annular manifold around its outer periphery, and each suction port is connected to the manifold through a short branch pipe; the manifold is connected to the gas-liquid separation filter assembly through a flexible negative pressure pipeline; the open-type fumigation hood moves synchronously with the workpiece and moves relative to the fixed laser processing head along a preset processing trajectory.

10. A pulsed laser processing method using the system described in any one of claims 1 to 9, characterized in that, include: Secure the workpiece and the open fume hood together to the moving platform; activate the negative pressure suction system to create a circumferential airflow; and input compressed air into the central phosgene channel. The processing fluid enters the annular liquid chamber through the tangential inlet and drives the rotor assembly to rotate, so that the processing fluid is output through the annular slit outlet; the central compressed air and the rotating liquid flow together form a central hollow annular swirling liquid mist; the pulsed laser beam passes through the central hollow area and acts on the workpiece processing area; the moving platform drives the workpiece and the fume hood to move synchronously to realize laser processing; the annular swirling liquid mist is used to cool the processing area and wash away ablation products, and the negative pressure suction system is used to capture smoke, liquid mist and particles; the processing fluid is recycled after gas-liquid separation and filtration.

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