Laser-water jet composite cutting device and method for galvanized air pipe

Abstract

The invention discloses a laser-water jet composite cutting device and method for a galvanized air pipe. The laser-water jet composite cutting device comprises a workbench, and a composite cutting head, a multi-axis movement mechanism, a self-adaptive clamping mechanism and a high-pressure circulating water conveying mechanism which are arranged on the workbench; the composite cutting head comprises a laser emitting assembly, a water jet assembly and a light path coupling assembly, and the light path coupling assembly is arranged below the laser emitting assembly and used for coaxially coupling a laser beam emitted by the laser emitting assembly and a high-pressure water column jetted by the water jet assembly. Through the composite action of the laser and the water column, the laser instantly melts the material, the water column immediately scours the slag and strongly cools the slag, a heat affected zone is almost eliminated, a notch is smooth and burr-free, a zinc coating is completely protected, and the notch is in a metal primary color; and the unique tangential water inlet rotational flow coupling cavity design is adopted, so that the core problems of bubble interference and flow field instability in water-guided laser are effectively solved, and the stability and reliability of laser energy transmission during long-time continuous processing are ensured.

Description

Technical Field

[0001] This invention relates to the field of laser processing and waterjet cutting technology, and in particular to a laser-waterjet composite cutting device and method for galvanized air ducts. Background Technology

[0002] Galvanized ducts are widely used in ventilation duct systems due to their excellent corrosion resistance and cost advantages. Traditional cutting methods mainly include mechanical shearing, plasma cutting, and pure laser cutting. However, mechanical shearing produces burrs and deformation, requiring secondary processing, and is difficult and inefficient for cutting complex curves; plasma cutting results in a large heat-affected zone, poor cut quality, severe ablation of the galvanized layer, blackening of the edges, loss of corrosion resistance, and significant smoke and dust pollution; while pure laser cutting offers high precision, the high temperature still causes oxidation and evaporation of the zinc layer at the cut edges of galvanized steel sheets, forming a black oxide layer that affects appearance and corrosion resistance, and poses a risk of thermal deformation.

[0003] In recent years, water-guided laser cutting technology has shown advantages in the field of precision machining due to its combination of the high energy density of lasers and the cooling and scouring effects of water jets. However, although existing general-purpose water-guided laser equipment (such as the patent with publication number CN117415891A) has high power and pressure, its optical coupling structure is simple. When processing galvanized pipes for a long time, it is prone to reduced laser coupling efficiency and unstable cutting due to water quality fluctuations and bubble interference, which affects the overall processing efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a laser-waterjet composite cutting device and method for galvanized air ducts, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A laser-waterjet composite cutting device for galvanized air ducts, comprising: Workbench; A composite cutting head, mounted on the workbench, is used to cut galvanized air ducts; A multi-axis motion mechanism is fixedly installed above the worktable via a fixed base. It is used to drive the composite cutting head and generate relative motion with the galvanized air duct to be cut. A high-pressure circulating water supply mechanism is located on one side of the workbench, and its output end is connected to the composite cutting head through a high-pressure pipeline to provide high-pressure pure water to the composite cutting head. An adaptive clamping mechanism is set on the worktable for clamping and fixing galvanized air ducts of different sizes; The control system is electrically connected to the composite cutting head, the multi-axis motion mechanism, the high-pressure circulating conveying mechanism, and the adaptive clamping mechanism, respectively, and is used to coordinate and control the composite cutting head, the multi-axis motion mechanism, the high-pressure circulating conveying mechanism, and the adaptive clamping mechanism. The composite cutting head includes a laser emitting component, a water jet spraying component, and an optical path coupling component. The optical path coupling component is located below the laser emitting component and is used to coaxially couple the laser beam emitted by the laser emitting component with the high-pressure water jet sprayed by the water jet spraying component.

[0006] Based on the above technical solution, the present invention can be further improved as follows.

[0007] Furthermore, the optical path coupling component includes: A sealed outer shell with a cylindrical coupling cavity inside; A light-transmitting and sealed window is fixedly installed on the top of the sealed housing. The light-transmitting and sealed window is located directly below the optical path of the laser emitting assembly. It is used to seal the upper end of the coupling cavity and allow the laser beam of the laser emitting assembly to pass through without damage. The water inlet is located on the side wall of the sealed housing and is connected to the water outlet of the high-pressure circulation conveying mechanism through a high-pressure pipeline. The axis of the water inlet is tangent to the inner wall of the coupling cavity, so that the high-pressure pure water forms a forced vortex around the central axis in the coupling cavity. Centrifugal force is used to purify the flow field and stabilize the central optical path area, thereby improving the stability of the high-pressure pure water flow in the coupling cavity. The nozzle seat is fixedly installed at the bottom of the sealing shell. Its inner cavity has a conical flow channel that extends to the coupling cavity. The cone angle of the conical flow channel is 12° to 35° and its inner surface is polished to guide the high-pressure pure water to accelerate smoothly and converge downwards.

[0008] Furthermore, the water jet assembly includes: A precision nozzle is detachably mounted on the bottom of the nozzle holder, with its upper inlet smoothly connected to the tapered flow channel inside the nozzle holder, and its lower outlet being a micro-hole with a diameter of 0.1 to 0.5 mm. The laser beam output by the laser emitting assembly passes vertically through the light-transmitting sealed window and is focused on the inlet center plane of the precision nozzle.

[0009] Furthermore, the optical path coupling component also includes: A focusing lens assembly, positioned above the light-transmitting sealed window, is used to converge the laser beam output from the laser emitting assembly. A focusing ring, located above and connected to the focusing lens group, is used to adjust the focusing position of the laser beam along the optical axis to match the cutting requirements of different heights. A collimation protection lens is placed in the optical path between the light-transmitting sealing window and the focusing lens group to isolate water mist penetration within the coupling cavity.

[0010] Furthermore, the light-transmitting and sealing window is a flat quartz glass window, and the periphery of the light-transmitting and sealing window is sealed to the sealing shell by a first high-pressure sealing ring.

[0011] Furthermore, the precision nozzle is a diamond nozzle or a ruby ​​nozzle, and a second high-pressure sealing ring is provided between the precision nozzle and the nozzle seat.

[0012] Furthermore, the axial length H of the coupling cavity between the light-transmitting sealing window and the nozzle seat satisfies the relationship D of the inlet diameter D of the precision nozzle: 3D ≤ H ≤ 5D. This ensures that the laser beam output from the laser emitting component has a suitable distance in the high-pressure pure water within the coupling cavity for mode shaping before entering the precision nozzle.

[0013] Furthermore, the high-pressure circulating water conveyance mechanism includes a water tank, a multi-stage filter, a booster pump, an energy storage device, and a pressure stabilizing valve connected in sequence. The water tank is equipped with a cooling device and a water quality monitoring module, which is used to detect the conductivity and particulate matter content of the water in real time.

[0014] Furthermore, the adaptive clamping mechanism includes: A rotating clamp is fixedly installed above the workbench via a support base. The clamping end of the rotating clamp is equipped with multiple sets of pneumatic jaws for clamping and fixing galvanized air ducts. A drive motor is fixedly installed on the side of the workbench. The output end of the drive motor is provided with a drive pulley, and the outer wall of the housing of the rotary fixture is provided with a driven pulley. The drive pulley is connected to the driven pulley through a transmission belt and is used to drive the rotary fixture to rotate the galvanized air duct around its own axis. The V-shaped positioning block is located on the side of the worktable away from the rotating fixture. The support surface of the V-shaped positioning block is equipped with a press-type spring ball for stable support of the galvanized air duct.

[0015] Furthermore, the multi-axis motion mechanism includes an X-axis linear module and a Y-axis linear module. The two ends of the X-axis linear module are fixedly connected to the worktable via a fixing bracket. The Y-axis linear module is vertically mounted on the slide of the X-axis linear module. The composite cutting head is fixedly mounted on the slide of the Y-axis linear module.

[0016] Furthermore, the control system includes: A visual positioning module is used to identify the outline of the air duct; The process parameter database stores combinations of laser power, water pressure, and cutting speed parameters corresponding to galvanized sheets of different thicknesses. The real-time monitoring module is used to monitor water pressure fluctuations, laser power stability, and cut surface quality during the cutting process.

[0017] Furthermore, the workbench is equipped with a drying device, which includes a nitrogen purging pipe and a hot air dryer, used to purge and dry the surface of the galvanized air duct after cutting.

[0018] Furthermore, the workbench has a waste liquid collection port on its surface and a waste liquid recovery tank below it. The waste liquid recovery tank is connected to a multi-stage filter of a high-pressure circulating water conveyance mechanism through a pipeline to realize the recovery and recycling of cutting wastewater.

[0019] A laser-waterjet composite cutting method for galvanized air ducts specifically includes the following steps: S10, Clamping and Positioning: Place the galvanized duct in the adaptive clamping mechanism, identify the outline of the galvanized duct and the starting point of the cutting path through the vision positioning module, and adjust the clamp to tighten. S20. Process parameter setting: Based on the duct material and thickness, retrieve the corresponding laser power, water pressure, and cutting speed parameters from the process parameter database; S30. Water column establishment and stabilization: Start the high-pressure circulating water supply mechanism to inject high-pressure pure water into the coupling cavity, and wait for the water column sprayed from the precision nozzle to reach a stable laminar flow state. S40, Laser Coupling Calibration: Start the laser emission assembly in low power mode, adjust the focusing ring to precisely focus the laser beam onto the inlet center plane of the precision nozzle; S50, Composite Cutting Process: Based on the material and thickness of the galvanized duct, the process parameters are called to increase the power of the laser emitting component to the working value; the control system drives the multi-axis motion mechanism and the rotating fixture to work, so that the laser-water column composite beam can cut the rotating galvanized duct along the preset path; S60. Post-processing: After cutting, the laser emitting component and the high-pressure circulating water supply mechanism are turned off one after the other. Then, the drying device is started to purge the cut of the galvanized air duct with nitrogen and dry it with hot air.

[0020] Furthermore, in step S40, to ensure the concentricity of the laser beam and the precision nozzle, photosensitive paper is placed below the precision nozzle. By observing the position of the light spot on the photosensitive paper placed below the water column, the offset of the focusing ring is adjusted for compensation, so as to calibrate the concentricity of the laser beam and the precision nozzle.

[0021] Furthermore, in step S50, the power of the laser emitting component is 200-1000W, the water pressure of the high-pressure pure water in the coupling cavity is 1-10MPa, and the rotational cutting speed of the galvanized air duct is 30-200mm / s.

[0022] Furthermore, in step S60, during drying, the cut surface of the galvanized air duct is first purged with nitrogen gas at 0.3-0.5 MPa for 1-5 seconds to remove surface water, and then hot air at 40-60°C is circulated and dried for 2-5 seconds.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Superior cutting quality: The combined effect of laser and water jet melts the material instantly, while the water jet immediately washes away the molten slag and provides powerful cooling, virtually eliminating the heat-affected zone. This results in a smooth, burr-free cut that fully protects the galvanized layer and leaves the cut in its original metallic color.

[0024] 2. High processing stability: The unique tangential water inlet vortex coupling cavity design effectively solves the core problems of bubble interference and flow field instability in water-guided lasers, ensuring the stability and reliability of laser energy transmission during long-term continuous processing.

[0025] 3. Wide process adaptability: The control system can automatically match the laser power, water pressure and cutting speed according to the material thickness and the curvature of the cutting path, so as to achieve high-quality cutting from thin tubes to medium and thick tubes, and from straight lines to complex curves.

[0026] 4. Complete production closed loop: It integrates automatic clamping, precision cutting and rust prevention drying functions, forming a complete solution for galvanized air duct processing, improving the level of automation and production cycle.

[0027] 5. Environmental protection and economy: By setting up a drying device to purge the cuts of the galvanized air duct with nitrogen and dry with hot air, the workpiece is prevented from rusting, which reduces the subsequent processing costs and environmental burden. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the adaptive clamping mechanism of the present invention; Figure 3 This is a schematic diagram of the structure of the composite cutting head of the present invention; Figure 4 This is a schematic diagram of the drying device of the present invention; Figure 5 This is a schematic diagram of the connection between the laser emitting component and the optical path coupling component of the present invention; Figure 6 This is a schematic diagram of the optical path coupling component of the present invention; Figure 7 This is an exploded view of the optical path coupling component of the present invention; Figure 8 yes Figure 6 The structural cross-sectional view of AA is shown below; Figure 9This is a block diagram illustrating the working principle of the present invention.

[0029] The components include: 1. Workbench; 2. Composite cutting head; 201. Laser emitting assembly; 202. Water jet assembly; 2021. Nozzle holder; 2022. Precision nozzle; 2023. Conical flow channel; 203. Optical path coupling assembly; 2031. Sealed housing; 2032. Coupling cavity; 2033. Transparent sealed window; 2034. Water inlet; 2035. Focusing lens assembly; 2036. Focusing ring; 2037. Collimation protection lens; 3. Galvanized air duct; 4. Multi-axis motion mechanism; 401. X-axis linear module; 402. Y-axis linear module; 403. Fixing frame; 5. Fixing base; 6. High-pressure circulating water conveyance mechanism. 601. Water tank; 602. Multi-stage filter; 603. Booster pump; 604. Energy storage device; 605. Pressure regulating valve; 7. High-pressure pipeline; 8. Adaptive clamping mechanism; 801. Rotary clamp; 802. Support base; 803. Pneumatic gripper; 804. Drive motor; 805. Drive pulley; 806. Driven pulley; 807. Transmission belt; 808. V-shaped positioning block; 809. Press-type spring ball; 9. Control system; 10. First high-pressure sealing ring; 11. Second high-pressure sealing ring; 12. Drying device; 1201. Nitrogen purging pipe; 1202. Hot air dryer; 13. Waste liquid collection port. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings.

[0031] Please see Figures 1 to 8 This embodiment provides a laser-waterjet composite cutting device for galvanized air ducts 3, applied to the precision cutting of galvanized air ducts 3 in ventilation duct systems. The device includes a worktable 1, which is a standard machining platform in the prior art, typically made of cast iron or welded steel plate, possessing sufficient rigidity and stability. The surface of the worktable 1 is precision machined to provide a reference surface for the subsequent installation of various functional components.

[0032] The composite cutting head 2 is mounted on the workbench 1 and is used to cut the galvanized air duct 3. This composite cutting head 2 is the core component of this invention, enabling the synergistic effect of laser and water jet. The composite cutting head 2 includes a laser emitting assembly 201, a water jet spraying assembly 202, and an optical path coupling assembly 203. The laser emitting assembly 201 uses a fiber laser or a semiconductor laser, capable of outputting a high-power-density laser beam. The water jet spraying assembly 202 is responsible for spraying high-pressure pure water to form a high-speed water jet. The optical path coupling assembly 203 is located below the laser emitting assembly 201 and is used to coaxially couple the laser beam emitted by the laser emitting assembly 201 with the high-pressure water jet sprayed by the water jet spraying assembly 202, achieving stable transmission of laser energy within the water jet and forming a high-pressure water jet with laser energy. This composite beam combines the high energy density of a laser with the cooling and scouring characteristics of a water jet.

[0033] In a preferred embodiment, the present invention may be further configured as follows: Figure 3 As shown, the multi-axis motion mechanism 4 is fixedly mounted above the worktable 1 via a fixed base 5. It drives the composite cutting head 2 to move relative to the galvanized duct 3 to be cut. Specifically, the multi-axis motion mechanism 4 includes an X-axis linear module 401 and a Y-axis linear module 402. The X-axis linear module 401 is fixedly connected to the worktable 1 at both ends via a fixed bracket 403, providing horizontal freedom of movement. The Y-axis linear module 402 is vertically mounted on the slide of the X-axis linear module 401, providing vertical freedom of movement. The composite cutting head 2 is fixedly mounted on the slide of the Y-axis linear module 402. Through the coordinated movement of the two axes, the composite cutting head 2 can move along any path in the two-dimensional plane, meeting the needs of different cutting trajectories. The linear modules are driven by ball screws or linear motors, featuring high positioning accuracy and smooth operation.

[0034] In a preferred embodiment, the present invention may be further configured as follows: Figure 1As shown, the high-pressure circulating water supply mechanism 6 is located on one side of the workbench 1, and its output end is connected to the composite cutting head 2 through a high-pressure pipeline 7 to provide high-pressure pure water to the composite cutting head 2. The high-pressure circulating water supply mechanism 6 includes a water tank 601, a multi-stage filter 602, a booster pump 603, an energy storage device 604, and a pressure regulating valve 605 connected in sequence. The water tank 601 is used to store process water. The water tank 601 is equipped with a cooling device and a water quality monitoring module (not shown in the figure). The cooling device maintains a stable water temperature through a refrigeration cycle to avoid affecting the physical properties of the water due to temperature rise. The water quality monitoring module is used to detect the conductivity and particulate matter content of the water in real time to ensure that the water quality meets the requirements of laser coupling. When the conductivity or particulate matter content exceeds the standard, the system automatically alarms and starts a deep filtration or water replacement program. The multi-stage filter 602 adopts a precision filter element series structure to remove solid particles, impurities, and microorganisms from the water step by step to ensure that the water entering the coupling chamber 2032 meets the high purity requirements. The booster pump 603 pressurizes the pure water in the water tank 601 to the working pressure, the energy storage device 604 is used to absorb pressure fluctuations, and the pressure regulating valve 605 precisely controls the output pressure. The three work together to ensure a stable high-pressure pure water flow to the composite cutting head 2.

[0035] In a preferred embodiment, the present invention may be further configured as follows: Figure 2As shown, the adaptive clamping mechanism 8 is mounted on the worktable 1 and is used to clamp and fix galvanized air ducts 3 of different sizes. The adaptive clamping mechanism 8 includes a rotary clamp 801, a drive motor 804, and a V-shaped positioning block 808. The rotary clamp 801 is fixedly mounted on the worktable 1 via a support base 802. The clamping end of the rotary clamp 801 is equipped with multiple sets of pneumatic grippers 803 for clamping and fixing the galvanized air ducts 3. The number of pneumatic grippers 803 is usually three or four sets, evenly distributed circumferentially, and they are opened and closed synchronously through pneumatic control, which can adapt to air ducts of different diameters. The clamping surface of the pneumatic grippers 803 is equipped with an anti-slip pad to increase friction and prevent the air duct from slipping or being damaged during clamping. The drive motor 804 is fixedly installed on the side of the workbench 1. The output end of the drive motor 804 is equipped with a drive pulley 805, and the outer wall of the housing of the rotary fixture 801 is equipped with a driven pulley 806. The drive pulley 805 is connected to the driven pulley 806 through a transmission belt 807, which is used to drive the rotary fixture 801 to rotate the galvanized air duct 3 around its own axis. The drive motor 804 is a servo motor or a stepper motor with adjustable speed. It achieves speed reduction and torque increase through belt transmission, so that the air duct rotates at a set speed. Combined with the linear motion of the composite cutting head 2, it can realize spiral cutting or circumferential cutting of the air duct surface. The V-shaped positioning block 808 is set on the side of the workbench 1 away from the rotary fixture 801. The support surface of the V-shaped positioning block 808 is equipped with a press-type spring ball 809 for stable support of the galvanized air duct 3. The V-shaped positioning block 808 is a passive support structure. Its V-shaped groove forms two-point contact with the outer cylindrical surface of the duct, providing radial support. The press-type spring ball 809 generates elastic deformation under the weight of the duct, providing flexible support force, compensating for manufacturing errors and installation deviations of the duct, and ensuring that the duct maintains axial stability during rotation.

[0036] In a preferred embodiment, the present invention may be further configured as follows: Figure 1As shown, the control system 9 is located on one side of the workbench 1 and is electrically connected to the composite cutting head 2, the multi-axis motion mechanism 4, the high-pressure circulating conveying mechanism, and the adaptive clamping mechanism 8. It coordinates and controls these components to achieve automated operation of the entire cutting device. The control system 9 includes a main controller, a vision positioning module, a process parameter database, and a real-time monitoring module. The main controller uses a PLC or industrial computer to receive signals from various sensors, execute control logic, and output control commands. The vision positioning module uses an industrial camera and image processing algorithms to identify the duct outline, locate the cutting starting point, and achieve automatic alignment. The process parameter database stores combinations of laser power, water pressure, and cutting speed parameters corresponding to different thicknesses of galvanized steel sheets, automatically calling the matching process parameters based on the workpiece information. The real-time monitoring module monitors water pressure fluctuations, laser power stability, and cut surface quality during the cutting process. It automatically adjusts or alarms when parameters deviate from the set range to ensure consistent processing quality.

[0037] In a preferred embodiment, the present invention may be further configured as follows: Figure 6 , Figure 7 and Figure 8 As shown, the core technological innovation of this invention, the optical path coupling component 203 includes a sealed outer shell 2031, a light-transmitting sealed window 2033, a water inlet 2034, a nozzle seat 2021, and a precision nozzle 2022. A cylindrical coupling cavity 2032 is formed inside the sealed outer shell 2031. This coupling cavity 2032 is a high-pressure sealed cavity, capable of withstanding the working pressure of high-pressure pure water. The sealed outer shell 2031 is made of stainless steel or aluminum alloy, with a wall thickness sufficient to withstand the working pressure. The inner wall surface is precision machined and polished to reduce water flow resistance.

[0038] A light-transmitting sealing window 2033 is fixedly installed on the top of the sealing housing 2031. Located directly below the optical path of the laser emitting assembly 201, the light-transmitting sealing window 2033 seals the upper end of the coupling cavity 2032 and allows the laser beam from the laser emitting assembly 201 to pass through without damage. The light-transmitting sealing window 2033 is a flat quartz glass window. Quartz glass has high transmittance and low absorption for commonly used laser wavelengths, and can withstand high-power lasers without thermal damage. The periphery of the light-transmitting sealing window 2033 is sealed to the sealing housing 2031 by a first high-pressure sealing ring 10. The first high-pressure sealing ring 10 is made of high-pressure resistant rubber material, and a reliable seal is achieved through a compression structure to prevent high-pressure water leakage from the joint surface.

[0039] The water inlet 2034 is located on the side wall of the sealed housing 2031 and is connected to the outlet of the high-pressure circulation conveying mechanism via the high-pressure pipeline 7. The axis of the water inlet 2034 is tangential to the inner wall of the coupling cavity 2032, so that the high-pressure pure water forms a forced vortex around the central axis in the coupling cavity 2032. Centrifugal force is used to purify the flow field and stabilize the central optical path area, thereby improving the stability of the high-pressure pure water flow in the coupling cavity 2032. This is the key technical feature of the present invention. Unlike the direct forward water inlet method in the prior art, the tangential water inlet causes the high-pressure pure water to form a spiral upward or downward vortex motion along the inner wall after entering the coupling cavity 2032. Under the action of centrifugal force, the residual microbubbles and particles in the water are thrown to the outer wall, while a relatively pure and stable water body is formed in the central area. This provides a uniform medium environment for the transmission of the laser beam, effectively solves the problem of laser scattering and energy loss caused by bubble interference, and significantly improves the stability of long-term continuous processing.

[0040] In a preferred embodiment, the present invention may be further configured as follows: Figure 6 , Figure 7 and Figure 8 As shown, the water jet assembly 202 includes a nozzle seat 2021 and a precision nozzle 2022. The nozzle seat 2021 is fixedly installed at the bottom of the sealed housing 2031, and its inner cavity has a conical flow channel 2023 that extends to the coupling cavity 2032. The cone angle of the conical flow channel 2023 is 12° to 35°, and its inner surface is mirror-polished to guide the high-pressure pure water to accelerate smoothly and converge downwards. The conical flow channel 2023 acts as a gradual transition, allowing the high-pressure water in the swirling state within the coupling cavity 2032 to gradually converge towards the center and accelerate. The cone angle range is optimized; too small a cone angle leads to an excessively long flow channel and increased resistance, while too large a cone angle causes abrupt changes in flow pattern and generates eddies. A moderate cone angle ensures a smooth transition of the flow field. The inner surface polishing treatment reduces surface roughness, decreases frictional resistance and turbulence, and improves the laminar flow characteristics of the water.

[0041] The precision nozzle 2022 is detachably mounted on the bottom of the nozzle holder 2021. The upper inlet of the precision nozzle 2022 smoothly connects to the conical flow channel inside the nozzle holder 2021, while the lower outlet of the precision nozzle 2022 is a micro-orifice with a diameter of 0.1–0.5 mm. The precision nozzle 2022 is made of diamond or ruby, both materials possessing extremely high hardness and excellent wear resistance, capable of withstanding high-pressure water flow for extended periods while maintaining orifice accuracy. A second high-pressure sealing ring 11 is provided between the precision nozzle 2022 and the nozzle holder 2021, and a detachable connection is achieved via threads or a quick-change interface, allowing for rapid disassembly and replacement when the precision nozzle 2022 wears or requires a different orifice diameter. The micro-orifice outlet at the lower end of the precision nozzle 2022 accelerates the high-pressure water to extremely high speeds, forming a continuous water column with powerful kinetic energy. This water column serves simultaneously as both the laser transmission medium and the cutting medium.

[0042] The laser beam output from the laser emitting assembly 201 passes vertically through the light-transmitting sealed window 2033 and is focused on the inlet center plane of the precision nozzle 2022. Precise control of this focusing position is key to achieving efficient coupling. After entering the water medium, the laser beam's convergence angle changes due to the refractive index variation. By setting the focal point on the inlet center plane of the precision nozzle 2022, the laser beam enters the water column in optimal condition, maximizing the coupling efficiency of the laser energy.

[0043] In a preferred embodiment, the present invention may be further configured as follows: Figure 6 , Figure 7 and Figure 8 As shown, the optical path coupling assembly 203 also includes a focusing lens group 2035, a focusing ring 2036, and a collimation protection mirror 2037. The focusing lens group 2035 is positioned above the light-transmitting sealed window 2033 and is used to converge the laser beam output from the laser emitting assembly 201. The focusing lens group 2035 typically consists of one or more lenses. Appropriate coated lenses are selected based on the laser wavelength and power to achieve the focusing effect on the laser beam, controlling the focal point position and spot size. The focusing ring 2036 is positioned above and connected to the focusing lens group 2035, and is used to adjust the focusing position of the laser beam along the optical axis to match the cutting requirements of different heights. The focusing ring 2036 employs a threaded adjustment or rack and pinion adjustment mechanism. By rotating or moving the focusing ring 2036, the focusing lens group 2035 is finely adjusted along the optical axis, changing the focusing position of the laser beam to adapt to workpieces of different thicknesses or different coupling cavity 2032 sizes. A collimation protection mirror 2037 is positioned in the optical path between the light-transmitting sealing window 2033 and the focusing lens group 2035 to isolate water mist penetration within the coupling cavity 2032. The collimation protection mirror 2037 provides protection against minor leaks of water mist or splashing water droplets from the coupling cavity 2032, preventing contamination of the focusing lens group 2035. Simultaneously, it collimates or slightly focuses the laser beam, ensuring optical path quality.

[0044] In a preferred embodiment, the present invention may be further configured as follows: Figure 6 , Figure 7 and Figure 8As shown, the axial length H of the coupling cavity 2032 between the light-transmitting sealing window 2033 and the nozzle seat 2021 satisfies the relationship D of the inlet diameter D of the precision nozzle 2022: 3D≤H≤5D. This ensures that the laser beam output from the laser emitting component 201 has a suitable distance within the high-pressure pure water of the coupling cavity 2032 for mode shaping before entering the precision nozzle 2022. This dimensional relationship is the optimal range obtained through theoretical analysis and experimental verification. When H is too small, the laser beam enters the precision nozzle 2022 before sufficient shaping and stabilization, resulting in low coupling efficiency. When H is too large, the volume of the coupling cavity 2032 increases, the water swirling effect weakens, and the laser travels too far in the water, leading to increased energy attenuation. Within the range of 3D to 5D, sufficient shaping distance for the laser beam is ensured while maintaining a compact structure and efficient swirling purification effect.

[0045] In a preferred embodiment, the present invention can be further configured as shown in Figure 4; a drying device 12 is provided on the workbench 1, the drying device 12 including a nitrogen purging pipe 1201 and a hot air dryer 1202, used to purge and dry the surface of the galvanized air duct 3 after cutting. The nitrogen purging pipe 1201 is connected to a nitrogen source, and after cutting, it sprays a nitrogen gas stream with controllable pressure into the cut area to quickly blow away residual water droplets and water film on the cut surface. The hot air dryer 1202 generates a hot air stream with adjustable temperature to heat and dry the cut area, accelerating the evaporation of moisture. The two are used together, first using nitrogen to purge and remove surface water, and then using hot air to thoroughly dry, preventing oxidation and corrosion of the galvanized sheet cut due to residual moisture, thus protecting the integrity and anti-corrosion performance of the galvanized layer.

[0046] In a preferred embodiment, the present invention may be further configured as follows: Figure 1 As shown, a waste liquid collection port 13 is provided on the surface of the workbench 1, and a waste liquid recovery tank (not shown) is provided below the workbench 1. The waste liquid recovery tank is connected to the multi-stage filter 602 of the high-pressure circulating water conveyance mechanism 6 through a pipeline to realize the recovery and recycling of cutting wastewater. During the cutting process, the wastewater generated by the high-pressure water jet washing the workpiece carries a small amount of metal chips and cutting residues. It flows into the waste liquid recovery tank through the waste liquid collection port 13. After sedimentation and multi-stage filtration, the clean water re-enters the water tank 601, forming a closed-loop circulation system, reducing water consumption and waste liquid discharge, and meeting environmental protection requirements.

[0047] Please refer to the following: Figure 9 The present invention also provides a laser-waterjet composite cutting method for galvanized air duct 3, which uses the above-mentioned device and specifically includes the following steps: S10. Clamping and Positioning: The galvanized duct 3 is placed in the adaptive clamping mechanism 8. The visual positioning module identifies the contour of the galvanized duct 3 and the starting point of the cutting path, and the clamp is adjusted to tighten. The operator or the automatic feeding mechanism places the galvanized duct 3 to be processed between the rotating fixture 801 and the V-shaped positioning block 808. The industrial camera of the visual positioning module captures an image of the duct. The image processing system identifies the outer contour, end face position, and preset cutting path starting point mark of the duct, calculates the deviation between the actual position and the theoretical position of the duct, and the control system 9 drives the multi-axis motion mechanism 4 to perform position compensation based on the deviation value to achieve automatic alignment. Subsequently, the pneumatic gripper 803 moves to clamp and fix the duct, ensuring that the duct does not move or loosen during processing.

[0048] S20. Process Parameter Setting: Based on the duct material and thickness, the system retrieves the corresponding laser power, water pressure, and cutting speed parameters from the process parameter database. Operators input or scan workpiece information via a human-machine interface, including material type (e.g., galvanized steel sheet), sheet thickness, and galvanized layer thickness. The control system 9 then searches the process parameter database for matching parameter combinations, including the output power of the laser emitting component 201, the water pressure setting of the high-pressure circulating water supply mechanism 6, the cutting speed of the multi-axis motion mechanism 4, and the rotational speed of the rotary fixture 801. These parameters are automatically loaded into each actuator, eliminating the need for manual adjustments and improving efficiency and parameter consistency.

[0049] S30. Water Column Establishment and Stabilization: The high-pressure circulating water supply mechanism 6 is activated to inject high-pressure pure water into the coupling cavity 2032. The water column ejected from the precision nozzle 2022 reaches a stable laminar flow state. The control system 9 activates the booster pump 603. High-pressure pure water enters the coupling cavity 2032 tangentially through the high-pressure pipeline 7 from the inlet port 2034. A swirling flow is formed within the coupling cavity 2032, converging and accelerating through the conical flow channel of the nozzle seat 2021, finally being ejected at high speed from the micro-orifices of the precision nozzle 2022, forming a continuous and stable water column. Initially, the water column may exhibit pulsation or air bubbles. The system monitors the water flow state using pressure and flow sensors. Once the water column reaches a stable laminar flow state, a ready signal is issued. At this point, the water column surface is smooth and has good straightness, meeting the conditions for carrying the laser.

[0050] S40. Laser Coupling Calibration: Start the laser emitting assembly 201 in low-power mode and adjust the focusing ring 2036 to precisely focus the laser beam onto the inlet center plane of the precision nozzle 2022. The control system 9 first starts the laser emitting assembly 201 at low power (typically 10%–20% of rated power) to avoid equipment damage or safety risks caused by misalignment of the high-power laser. By adjusting the focusing ring 2036, the distance between the focusing lens group 2035 and the light-transmitting sealing window 2033 is changed, and the coupling effect between the laser beam and the water column is observed. To ensure the concentricity of the laser beam and the precision nozzle 2022, photosensitive paper is placed below the precision nozzle 2022. By observing the position of the light spot on the photosensitive paper below the water column, it is determined whether the laser beam accurately enters the center of the water column. If the light spot deviates from the center, the offset of the focusing ring 2036 is adjusted for compensation. This adjustment is repeated until the light spot is located in the center of the photosensitive paper and the shape of the light spot is symmetrical and uniform, indicating that the laser beam has been precisely focused onto the inlet center plane of the precision nozzle 2022, achieving efficient coupling.

[0051] S50, Composite Cutting Process: Based on the material and thickness of the galvanized duct 3, the process parameters are called, and the power of the laser emitting component 201 is increased to the working value. The control system 9 drives the multi-axis motion mechanism 4 and the rotating fixture 801 to work, causing the laser-water jet composite beam to cut the rotating galvanized duct 3 along a preset path. After the laser coupling calibration is completed, the control system 9 gradually increases the power of the laser emitting component 201 to the working set value, and at the same time starts the drive motor 804 of the rotating fixture 801, so that the galvanized duct 3 begins to rotate. The multi-axis motion mechanism 4 drives the composite cutting head 2 to move according to the preset cutting path program. The composite beam (laser-water jet) is aligned with the cutting starting point on the surface of the galvanized duct 3. The laser energy is focused on the workpiece through the water jet, instantly melting the plate of the galvanized duct 3. The high-pressure water jet immediately washes away the molten metal, and at the same time, it forcibly cools the cut, inhibiting the expansion of the heat-affected zone and the oxidation of the galvanized layer. In step S50, the power of the laser emitting component 201 is 200-1000W, the water pressure of the high-pressure pure water in the coupling cavity 2032 is 110MPa, and the rotary cutting speed of the galvanized air duct 3 is 30-200mm / s, with the specific value selected within the above range according to the thickness of the plate. By combining rotary cutting with linear motion, various cutting methods such as circumferential cutting, spiral grooving, and irregular hole processing can be achieved, meeting the diverse processing needs of the galvanized air duct 3.

[0052] S60. Post-processing: After cutting, the laser emitting component 201 and the high-pressure circulating water supply mechanism 6 are turned off successively. Then, the drying device 12 is started to purge the cut of the galvanized air duct 3 with nitrogen and dry it with hot air. When the cutting path is completed, the control system 9 first turns off the laser emitting component 201 to terminate the laser output, and then turns off the booster pump 603 of the high-pressure circulating water supply mechanism 6, and the water column gradually stops. At this time, there is a water film remaining on the cut surface. If it is not treated in time, the water film will cause the galvanized layer to oxidize and rust. The nitrogen purging pipe 1201 of the drying device 12 is aimed at the cut area and sprays nitrogen to blow away the surface water. The nitrogen pressure is 0.3-0.5MPa and the purging time is 1-5 seconds. Then, the hot air dryer 1202 is started, and the output hot air at a temperature of 40-60℃ is circulated and blown on the cut area to accelerate the evaporation of residual moisture. The hot air drying time is 2-5 seconds. After blowing and drying, the cut surface is dry and clean, the galvanized layer is intact, and it retains its original metallic color without oxidation or discoloration, meeting the requirements for subsequent use. After drying is complete, the pneumatic gripper 803 releases, and the operator or automatic unloading mechanism removes the processed air duct, completing a full processing cycle.

[0053] In other embodiments, the multi-axis motion mechanism 4 can also be equipped with a Z-axis and a rotation axis to form a three-axis or multi-axis linkage system, realizing a more complex three-dimensional spatial cutting path; the water inlet 2034 of the optical path coupling component 203 can be set in multiple ways, evenly distributed along the circumference, forming multiple tangential water inlets to further enhance the swirling effect; the micro-orifice diameter of the precision nozzle 2022 can be selected in the range of 0.1 to 0.5 mm according to the cutting accuracy requirements. The smaller the orifice diameter, the finer the water column and the narrower the kerf, but the higher the requirements for water quality and pressure; the control system 9 can be equipped with an adaptive control function, which can dynamically adjust the laser power and cutting speed by real-time monitoring of cutting quality parameters (such as kerf width and roughness) to achieve closed-loop control; the drying device 12 can also be equipped with a vacuum water suction device, which can quickly suck up the residual moisture at the cut through negative pressure to further shorten the drying time.

[0054] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A laser-waterjet composite cutting device for galvanized air ducts, characterized in that, include: Workbench (1); A composite cutting head (2) is installed on the workbench (1) and is used to cut galvanized air ducts (3); The multi-axis motion mechanism (4) is fixedly installed above the workbench (1) by a fixed seat (5), and is used to drive the composite cutting head (2) and generate relative motion with the galvanized air duct (3) to be cut; A high-pressure circulating water supply mechanism (6) is set on one side of the workbench (1), and its output end is connected to the composite cutting head (2) through a high-pressure pipeline (7) to provide high-pressure pure water to the composite cutting head (2); An adaptive clamping mechanism (8) is provided on the workbench (1) for clamping and fixing galvanized air ducts (3) of different sizes; The control system (9) is electrically connected to the composite cutting head (2), the multi-axis motion mechanism (4), the high-pressure circulating conveying mechanism and the adaptive clamping mechanism (8) respectively, and is used to coordinate and control the composite cutting head (2), the multi-axis motion mechanism (4), the high-pressure circulating conveying mechanism and the adaptive clamping mechanism (8); The composite cutting head (2) includes a laser emitting component (201), a water jetting component (202), and an optical path coupling component (203). The optical path coupling component (203) is located below the laser emitting component (201) and is used to coaxially couple the laser beam emitted by the laser emitting component (201) with the high-pressure water jet sprayed by the water jetting component (202).

2. The laser-waterjet composite cutting device for galvanized air ducts according to claim 1, characterized in that, The optical path coupling component (203) includes: A sealed outer shell (2031) has a cylindrical coupling cavity (2032) inside; A light-transmitting sealing window (2033) is fixedly installed on the top of the sealing housing (2031). The light-transmitting sealing window (2033) is located directly below the optical path of the laser emitting assembly (201) and is used to seal the upper end of the coupling cavity (2032) and allow the laser beam of the laser emitting assembly (201) to pass through without damage. The water inlet (2034) is located on the side wall of the sealed housing (2031). It is connected to the water outlet of the high-pressure circulation conveying mechanism through the high-pressure pipeline (7). The axis of the water inlet (2034) is tangent to the inner wall of the coupling cavity (2032) so that the high-pressure pure water forms a forced vortex around the central axis in the coupling cavity (2032). The centrifugal force is used to purify the flow field and stabilize the central optical path area, thereby improving the stability of the high-pressure pure water flow in the coupling cavity (2032).

3. The laser-waterjet composite cutting device for galvanized air ducts according to claim 1, characterized in that, The water jet assembly (202) includes: The nozzle seat (2021) is fixedly installed at the bottom of the sealing shell (2031). Its inner cavity has a conical flow channel that extends to the coupling cavity (2032). The cone angle of the conical flow channel is 12° to 35°. Its inner surface is polished to guide the high-pressure pure water to accelerate smoothly and converge downward. A precision nozzle (2022) is detachably installed at the bottom of the nozzle seat (2021). Its upper inlet is smoothly connected to the tapered flow channel (2023) inside the nozzle seat (2021). The lower outlet of the precision nozzle (2022) is a micro-hole with a diameter of 0.1 to 0.5 mm. The laser beam output by the laser emitting assembly (201) passes vertically through the light-transmitting sealed window (2033) and is focused on the inlet center plane of the precision nozzle (2022).

4. The laser-waterjet composite cutting device for galvanized air ducts according to claim 2, characterized in that, The optical path coupling component (203) also includes: A focusing lens assembly (2035) is disposed above the light-transmitting sealed window (2033) and is used to converge the laser beam output by the laser emitting assembly (201); A focusing ring (2036) is disposed above the focusing lens group (2035) and connected to the focusing lens group (2035) for adjusting the focusing position of the laser beam along the optical axis to match the cutting requirements of different heights. A collimation protection lens (2037) is disposed in the optical path between the light-transmitting sealing window (2033) and the focusing lens group (2035) to isolate water mist penetration in the coupling cavity (2032).

5. A laser-waterjet composite cutting device for galvanized air ducts according to claim 2, characterized in that, The light-transmitting and sealing window (2033) is a flat quartz glass window, and the periphery of the light-transmitting and sealing window (2033) is sealed to the sealing shell (2031) by a first high-pressure sealing ring (10).

6. A laser-waterjet composite cutting device for galvanized air ducts according to claim 2, characterized in that, The precision nozzle (2022) is a diamond nozzle or a ruby ​​nozzle, and a second high-pressure sealing ring (11) is provided between the precision nozzle (2022) and the nozzle seat (2021).

7. The laser-waterjet composite cutting device for galvanized air ducts according to claim 1, characterized in that, The high-pressure circulating water conveying mechanism (6) includes a water tank (601), a multi-stage filter (602), a booster pump (603), an energy storage device (604), and a pressure stabilizing valve (605) connected in sequence. The water tank (601) is equipped with a cooling device and a water quality monitoring module. The water quality monitoring module is used to detect the conductivity and particulate matter content of the water in real time.

8. A laser-waterjet composite cutting device for galvanized air ducts according to claim 1, characterized in that, The adaptive clamping mechanism (8) includes: A rotating clamp (801) is fixedly installed above the workbench (1) via a support base (802). The clamping end of the rotating clamp (801) is provided with multiple sets of pneumatic grippers (803) for clamping and fixing the galvanized air duct (3). A drive motor (804) is fixedly installed on the side of the workbench (1). The output end of the drive motor (804) is provided with a drive pulley (805). The outer wall of the housing of the rotary fixture (801) is provided with a driven pulley (806). The drive pulley (805) is connected to the driven pulley (806) through a transmission belt (807) and is used to drive the rotary fixture (801) to drive the galvanized air duct (3) to rotate around its own axis. V-shaped positioning block (808) is set on the side of the workbench (1) away from the rotating clamp (801). Press-type spring ball (809) is provided on the support surface of the V-shaped positioning block (808) for stable support of galvanized air duct (3).

9. A laser-waterjet composite cutting device for galvanized air ducts according to claim 1, characterized in that, The workbench (1) is equipped with a drying device (12), which includes a nitrogen purging pipe (1201) and a hot air dryer (1202) for purging and drying the surface of the galvanized air duct (3) after cutting.

10. A laser-waterjet composite cutting method for galvanized air ducts, using the apparatus described in any one of claims 1-9, specifically comprising the following steps: S10, clamping and positioning: place the galvanized air duct (3) in the adaptive clamping mechanism (8), identify the outline of the galvanized air duct (3) and the starting point of the cutting path through the visual positioning module, and adjust the clamp to tighten; S20. Process parameter setting: Based on the duct material and thickness, retrieve the corresponding laser power, water pressure, and cutting speed parameters from the process parameter database; S30, Water column establishment and stabilization: Start the high-pressure circulating water conveying mechanism (6) to inject high-pressure pure water into the coupling cavity (2032), and wait for the water column sprayed from the precision nozzle (2022) to reach a stable laminar flow state. S40, Laser Coupling Calibration: Start the laser emitting assembly (201) in low power mode, adjust the focusing ring (2036) to make the laser beam precisely focused on the inlet center plane of the precision nozzle (2022); S50, Composite Cutting Processing: Based on the material and thickness of the galvanized air duct (3), process parameters are called to increase the power of the laser emitting component (201) to the working value; the control system (9) drives the multi-axis motion mechanism (4) and the rotating fixture (801) to work, so that the laser-water column composite beam can cut the rotating galvanized air duct (3) along the preset path; S60. Post-processing: After the cutting is completed, the laser emitting component (201) and the high-pressure circulating water supply mechanism (6) are turned off one after the other. Then the drying device (12) is started to purge the cut of the galvanized air duct (3) with nitrogen and dry it with hot air.

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