Supersonic laser spraying device and method

Abstract

The invention discloses a supersonic speed laser spraying device and method, relates to the technical field of laser spraying, and realizes laser transmission and supersonic speed powder flow collaboration through cooperation of optical elements such as an output optical fiber, a collimating lens group and a convergent lens and a Laval nozzle structure. The method comprises the steps that multi-parameter closed-loop regulation and control are conducted, parameters such as the molten pool temperature and the powder flow divergence angle are monitored synchronously, and a process health index is constructed to trigger laser power, airflow pressure and powder feeding amount dynamic compensation; self-adaptive focus scanning is carried out, the focus position is adjusted in real time through a laser displacement sensor, and working modes are switched in linkage with a process health index; and lens abnormity diagnosis is carried out, a health index is constructed by using dual-wavelength transmissivity and wavefront distortion, and grading early warning and linkage powder feeding amount adjustment are carried out. According to the scheme, coating defects can be reduced, and the spraying precision and the system stability are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of laser spraying, and in particular to a supersonic laser spraying device and method. Background Art

[0002] Laser spraying technology is widely used for surface strengthening and repair in aerospace, machinery manufacturing, and other fields due to its advantages such as high coating bonding strength and small heat-affected zone. However, the existing supersonic laser spraying process faces multiple technical bottlenecks in practical applications: On the one hand, the multi-parameter coupling problems such as melt pool temperature fluctuations, powder flow divergence angle deviation, and element burnout during the spraying process make the coating prone to defects such as pores and cracks; on the other hand, traditional devices lack a dynamic control mechanism and are difficult to adapt to changes in the substrate surface morphology in real time, causing the focus position to shift and affecting the uniformity of the coating; in addition, under long-term high-power laser operation, thermal deformation and contamination of the optical lens will lead to deterioration of beam quality. The existing technology lacks effective real-time diagnostic methods, which can easily lead to spraying failure.

[0003] Current mainstream supersonic laser spraying devices have three major technical shortcomings: First, parameter control relies on manual experience and presets, and it is impossible to build a process health assessment system through real-time sensor data, resulting in the molten pool temperature deviating from the ideal range (0.8-0.95 times the melting point), difficulty in maintaining the supersonic state of the powder flow (Ma=2.0-2.5), and the element burn-out rate often exceeding the process threshold of 3%; Second, there is a lack of a focus position compensation mechanism. When the substrate surface changes in height due to spray accumulation or processing errors, the laser focus point cannot be dynamically adjusted, resulting in a decrease in the accuracy of the powder flow and laser intersection, and the coating thickness fluctuates by more than ±5μm; Third, the maintenance of the optical system lags behind, and there is a lack of quantitative monitoring of lens transmittance attenuation and wavefront distortion. Lens abnormalities often lead to a sudden drop in power density (e.g., below 15kW / cm²), resulting in insufficient powder pre-activation and accumulation of unmelted particles. Summary of the Invention

[0004] The purpose of the present invention is to solve the existing problems and to provide a supersonic laser spraying device and method.

[0005] The purpose of the present invention can be achieved through the following technical solutions: A supersonic laser spraying device, comprising: Output optical fiber, collimating lens barrel, collimating lens group, converging lens, lens barrel, collimating shaping lens group, conversion connector, air inlet nozzle, light-powder coupling channel, spray gun, end, powder inlet nozzle, powder buffer chamber, annular powder inlet channel; One end of the laser output head is provided with a collimating lens barrel, one end of the collimating lens barrel is provided with a lens barrel, one end of the lens barrel is provided with a conversion connector, one end of the conversion connector is provided with a Laval cavity, one end of the Laval cavity is provided with an end head, and a light-powder coupling channel is opened in the end head; A collimating lens group is symmetrically arranged in one end of the collimating lens barrel, a converging lens matched with the collimating lens group is arranged in one end of the lens barrel, and a collimating shaping lens group is arranged in the other end of the lens barrel; The conversion connector is also provided with an air inlet nozzle; A powder buffer chamber is provided in the end head, a powder inlet nozzle communicating with the outside is provided on the powder buffer chamber, and an annular powder inlet channel communicating with the light-powder coupling channel is also provided in the powder buffer chamber;

[0006] The laser output head, the collimating lens barrel, the lens barrel, the conversion connector, the Laval cavity, the end head and the light-powder coupling channel are interconnected.

[0007] Furthermore, the laser output head is a QBH, LOE, LOC or Qplus structure; The collimating lens barrel is used to install the collimating lens group and the converging lens; The collimating lens group is composed of 2-4 lenses and is used to collimate the divergent laser output by the laser output head; The converging lens is used to convert the collimated laser into a converging beam; The lens barrel is a lens barrel of a collimating and shaping lens group; The collimating and shaping lens group is used to convert the converged laser into a collimated beam with a diameter of 2mm-10mm, and collimate the laser into a flat-top beam; The conversion connector is used to connect the lens barrel of the lens assembly and the Laval nozzle body behind it; The gas inlet nozzle is used to inject high-pressure argon gas; The light-to-powder coupling channel is formed after the end head is connected to the Laval nozzle through threads and the end head is connected to the Laval cavity, forming a powder buffer chamber and an annular powder feed channel. The width of the annular powder feed channel is 0.5mm-1.5mm. The annular powder feed channel is the light-to-powder coupling channel for spraying powder in the Laval nozzle; The Laval chamber is the main body of the Laval nozzle of the spray gun, the inner cavity is a Laval structure, and the diameter of the thin diameter part is 2mm-10mm; high-pressure argon gas forms a supersonic airflow after passing through the thin diameter; The end head is connected to the Laval nozzle via threads; The powder feed nozzle injects the spraying powder using a powder feeder; The powder buffer chamber is formed after the end head and the Laval nozzle are connected by threads and the end head and the Laval chamber are connected in place;

[0008] The annular powder feeding channel is formed after the end head and the Laval nozzle are connected by threads and the end head and the Laval cavity are connected in place.

[0009] A method for a supersonic laser spraying device comprises the following steps: S1. Multi-parameter closed-loop dynamic control: Simultaneously monitor the three-dimensional temperature distribution of the molten pool, the powder flow divergence angle and convergence point offset, and the element burnout rate parameters to build a process health index. Based on the control trigger conditions, digital twin-driven parameter optimization is used to achieve dynamic adjustment of laser power, coordinated control of airflow pressure, and intelligent compensation of powder feed rate to reduce coating defects. S2, Adaptive Laser Focus Scanning: Real-time monitoring of the distance change between the spray gun and the substrate surface, calculation of focus compensation displacement, adjustment of the lens group axial position via the piezoelectric ceramic driver to correct the focus position, and linkage with the process health index system to switch to different working modes according to coating thickness fluctuations; S3. Real-time diagnosis of lens abnormalities: Through dual-wavelength transmittance monitoring and thermal deformation wavefront diagnosis, a lens health index is constructed and a graded response is performed. When a lens abnormality occurs, corresponding measures such as early warning, power reduction, and emergency shutdown are taken. At the same time, the powder feeding amount will also be adjusted in conjunction with the lens health index.

[0010] Furthermore, the specific operation steps of S1 are as follows: 101. Simultaneously monitor the temperature distribution of the molten pool, the offset between the powder flow divergence angle and the convergence point, and the element burnout rate; 102. Calculate the process health index (PHI) using the following expression: PHI = 0.4 × |temperature fluctuation rate| + 0.3 × divergence angle deviation rate + 0.3 × burnout rate deviation rate; control is triggered when PHI > 0.25 or element burnout rate > 2.5%; 103. Predicting porosity and bonding strength using long short-term memory neural network model; 104. Adaptive particle swarm optimization algorithm is used to solve the optimal laser power, air flow pressure and powder feeding rate; 15. Dynamic compensation execution: Adjust the laser power according to the difference between the average temperature of the molten pool and the target temperature and the temperature curvature; Adjust the airflow pressure according to the powder flow divergence angle and the offset of the convergence point; Adjust the powder feeding amount according to the element burnout rate and porosity change rate.

[0011] Furthermore, the specific operation steps of S2 are as follows: In the powder pre-activation step of focusing in the flat-top laser beam, a dynamic focus compensation mechanism is added, including: 201. Real-time surface topology monitoring: A laser displacement sensor is integrated at the end to measure the distance change ΔH between the spray gun and the substrate surface in real time; 202. Focus offset calculation: Based on the distance change ΔH and the preset distance d of the powder convergence point, calculate the focus compensation displacement: ΔF = k1 × ΔH × (d / d0), where k1 = 0.8 is the thermal expansion coefficient, d is the preset distance of the powder convergence point, and the value is set between 2mm and 10mm, d0 = 5mm reference distance, and ΔH is the distance change from the spray gun to the substrate surface; 203. Dynamic focus adjustment: The axial position of the collimating and shaping lens group is adjusted by the piezoelectric ceramic driver; the focus position correction formula is: F new =F0+ΔF, where F0 is the initial focus position, F new is the new focus position after state adjustment, ΔF is the calculated focus compensation displacement; 204. Linked with the PHI system: When the process health index PHI>0.2, the focus scanning system is activated. When the coating thickness fluctuation is less than ±5μm, it switches to energy-saving mode, that is, the sampling frequency is reduced to 1kHz.

[0012] Furthermore, the specific operation steps of S3 are as follows: 301. Calculate laser transmittance in real time through input power sensor and output power sensor; 302. Detecting the wavefront distortion of the laser beam in real time through a wavefront sensor; 303. Calculate the lens health index LHI based on the transmittance and wavefront distortion, and perform a graded response: When the LHI is in the range of 0.1 to 0.3, the optical system warning is triggered; When LHI is in the range of 0.3 to 0.5, reduce the laser power and start compressed air dust removal; When LHI is greater than 0.5, perform emergency shutdown and locate the faulty lens; 304. When LHI is greater than 0.3, the powder feeding amount will be automatically reduced; after the fault is eliminated, the powder feeding amount will gradually return to the initial value.

[0013] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention fundamentally improves the quality of spray coatings through real-time fusion and dynamic adjustment of multi-dimensional sensor data. By using infrared thermal imagers, high-speed CCDs and other equipment to synchronously monitor the melt pool temperature, powder flow morphology and element burnout, the constructed process health index can accurately capture process anomalies. When temperature fluctuations or burnout rates exceed the standard, parameters such as laser power and airflow pressure are automatically optimized. (2) The laser displacement sensor and piezoelectric ceramic drive system integrated in the present invention can respond to the subtle fluctuations on the substrate surface in real time, control the focus position adjustment accuracy to ±0.5μm, and ensure that the laser energy acts evenly on the powder flow. Lens health monitoring can provide early warning of optical component abnormalities through dual-wavelength transmittance detection and wavefront distortion analysis: when the lens performance deteriorates, the system will automatically reduce the powder feed rate and start dust removal to avoid spray failure due to deterioration of beam quality; (3) The present invention integrates the Laval nozzle and the annular narrow slit to form a supersonic airflow of high-pressure argon gas. The powder is evenly dispersed in the powder buffer chamber and then accelerated through the narrow slit, thereby improving the utilization rate. The collimating shaping lens group converts the laser into a flat-top beam, and the adaptive focus adjustment improves the powder heating efficiency. This device realizes fully automated operation from parameter monitoring to fault response. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings; Figure 1 This is a structural diagram of a supersonic laser spraying device in the present invention; Figure 2 The figure is a flow chart of a supersonic laser spraying method in the present invention.

[0015] Explanation of the reference numbers: 2-collimating lens barrel, 3-collimating lens group, 4-converging lens, 5-lens barrel, 6-collimating shaping lens group, 7-conversion connector, 8-air inlet nozzle, 9-light-powder coupling channel, 10-spray gun, 11-end, 12-powder inlet nozzle, 13-powder buffer chamber, 14-annular powder inlet channel. DETAILED DESCRIPTION

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0017] It should be understood that the terms “include” and “comprising” used in the specification and claims of the present disclosure indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections thereof.

[0018] It should also be understood that the terminology used in this disclosure is for the purpose of describing specific embodiments only and is not intended to limit the disclosure. As used in this disclosure and the claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It should be further understood that the term "and / or" as used in this disclosure and the claims refers to any and all possible combinations of one or more of the associated listed items, including and including these combinations.

[0019] like Figure 1 As shown, a supersonic laser spraying device includes: Output optical fiber, its core diameter is 20um-1000um; The laser output head 1 is a QBH structure (it can also be LOE, LOC or Qplus, etc.); The collimating lens barrel 2 is used for mounting the collimating lens group 3 and the converging lens 4; The collimating lens group 3 is composed of 2-4 lenses, and its function is to collimate the divergent laser output by the laser output head 1; The converging lens 4 converts the collimated laser into a converging beam 8; The lens barrel 5 is the lens barrel of the collimating and shaping lens group 6; The collimating and shaping lens group 6 is used to convert the converged laser into a relatively thin collimated beam with a diameter of 2mm-10mm, and collimate the laser into a flat-top beam; A conversion connector 7 is used to connect the lens barrel 5 of the lens assembly and the Laval nozzle body behind it; Gas inlet nozzle 8, used for injecting high-pressure argon gas; The light-powder coupling channel 9, after the end head 11 is connected to the Laval nozzle through threads, the end head 11 and the Laval chamber 10 are connected in place to form a powder buffer chamber 13 and an annular powder feed channel 14. The width of the annular powder feed channel is 0.5mm-1.5mm. The narrow gap is the light-powder coupling channel for the spray powder of the Laval nozzle; The Laval chamber 10 is the main body of the Laval nozzle of the spray gun. Its inner cavity is a Laval structure, and its thin diameter part can be 2mm-10mm in diameter. After the high-pressure argon gas passes through the thin diameter, it forms a supersonic airflow. The end 11 is connected to the Laval nozzle through a thread; Powder inlet nozzle 12, through which the powder dispenser can inject the spray powder; The powder buffer chamber 13 is formed by threaded connection of the end head 11 and the Laval nozzle and by connecting the end head 11 and the Laval chamber 10 in place; The annular powder inlet channel 14 is also formed by threaded connection between the end head 11 and the Laval nozzle and the end head 11 and the Laval chamber 10. The connection relationship includes: a collimating lens barrel 2 is provided at one end of the laser output head 1, a lens barrel 5 is provided at one end of the collimating lens barrel 2, a conversion connector 7 is provided at one end of the lens barrel 5, a Laval cavity 10 is provided at one end of the Laval cavity 10, an end head 11 is provided at one end of the Laval cavity 10, and a light-powder coupling channel 9 is provided in the end head 11; a collimating lens group 3 is symmetrically provided in one end of the collimating lens barrel 2, a converging lens 4 that cooperates with the collimating lens group 3 is provided at one end of the lens barrel 5, and a collimating shaping lens group 6 is provided in the other end of the lens barrel 5; an air inlet nozzle 8 is also provided on the conversion connector 7; a powder buffer chamber 13 is provided in the end head 11, a powder inlet nozzle 12 connected to the outside is provided on the powder buffer chamber 13, and an annular powder inlet channel 14 connected to the light-powder coupling channel 9 is also provided in the powder buffer chamber 13; the laser output head 1, the collimating lens barrel 2, the lens barrel 5, the conversion connector 7, the Laval cavity 10, the end head 11 and the light-powder coupling channel 9 are interconnected; Laser optical path, including: output optical fiber → laser output head 1 → collimating lens barrel 2 → collimating lens group 3 → converging lens 4 → lens barrel 5 → collimating shaping lens group 6 → flat top beam; The gas-powder coordination module includes: a gas flow path: a gas inlet nozzle 8 → a conversion connector 7 → a Laval cavity 10 → an annular powder inlet channel 14, i.e., a light-powder coupling channel 9; Powder flow path: powder inlet nozzle 12 → powder buffer chamber 13 → annular powder inlet channel 14 → throat of Laval chamber 10; The process of pre-activating powder focused within a flat-top laser beam is as follows: the divergent laser light output from the laser output head 1 is collimated into a parallel beam by a collimating lens assembly 3 and a converging lens 4. The parallel beam is converted into a quasi-flat-top beam with a diameter of 2–10 mm by a collimating shaping lens assembly 6. A powder convergence point is set inside the nozzle outlet (2–10 mm from the end face) so that the supersonic powder flow intersects with the flat-top beam in a closed cavity. The flat-top beam uniformly heats the powder flow at a power density of 15–30 kW / cm², ensuring that the particle surface temperature reaches 0.8–0.95 times the melting point (temperature difference < 50 K). The powder buffer chamber uniform flow-narrow slit accelerated collaborative powder feeding process includes: high-pressure argon gas (pressure 1.5-2.5MPa) is injected into the powder buffer chamber 13 through the air inlet nozzle 8 to form a cyclonic flow field (flow rate 50-80m / s); the spray powder is injected into the powder buffer chamber 13 through the powder inlet nozzle 12 and uniformly dispersed in the cyclonic flow field (agglomeration rate <3%); the powder is accelerated into the nozzle through the annular powder inlet channel 14 (width 0.5-1.5mm) and reaches supersonic speed (Ma=2.0-2.5) at the throat; the powder flow converges into a dense flow beam with a diameter of ≤1mm (divergence angle <5°) inside the nozzle outlet, thereby improving the powder utilization rate.

[0020] refer to Figure 2, a supersonic laser spraying method, comprising the following steps: Step 1: Multi-parameter closed-loop dynamic control, synchronously monitoring the three-dimensional temperature distribution of the molten pool, the powder flow divergence angle and convergence point offset, and the element burnout rate parameters, to build a process health index. Based on the control trigger conditions, parameter optimization driven by digital twins is implemented to achieve dynamic adjustment of laser power, coordinated control of airflow pressure, and intelligent compensation of powder feed rate to reduce coating defects; Multi-source sensor signal acquisition and feature fusion: Simultaneous monitoring of three core parameters: Infrared thermal imager captures 3D temperature distribution of the melt pool (spatial resolution 0.1mm, sampling rate 10kHz); high-speed CCD measurement of powder flow divergence angle and convergence point offset (accuracy ±0.05mm); plasma spectrometer detects element burnout rate Calculated by the intensity of the 358.1nm spectral line of iron): η = k × (integral of observed spectrum intensity - integral of reference spectrum intensity) / integral of reference spectrum intensity, (coefficient k = 0.15, integral wavelength range 358 ± 5nm); Constructing the Process Health Index (PHI): Where, is the molten pool temperature (collected by infrared thermal imager), is the reference temperature (standard value), reference value: (standard divergence angle), is the element burnout rate (detected by plasma spectrometer); (maximum allowable burnout rate); control trigger conditions: or ; Digital twin-driven parameter optimization and real-time prediction of coating defects: Input parameters: laser power P, airflow pressure p, powder feed rate Vf; Output prediction value through pre-trained long short-term memory neural network: porosity prediction value ; Predicted value of binding strength ; LSTM is a prediction function based on long short-term memory neural network; Adaptive Particle Swarm Optimization (APSO) solves the optimal parameters: Objective function: Minimize ; Where J is the objective function, used to optimize parameters; Constraints: ; ; ; Output the global optimal parameter group: ; Multi-channel decoupling compensation execution: Laser power dynamic adjustment (suppression of thermal cracks): ; Coefficient: K1=100W / ℃, K3=0.05×P max ;parameter: is the average temperature of the molten pool, T avg is the average temperature of the molten pool, Lap T is the temperature curvature (unit: K / mm²); Airflow pressure coordinated control (stable powder flow): Δp=K2×θ+K4×(Δd / d0)×p max ; where θ is the powder flow divergence angle, Δp is the airflow pressure adjustment amount, Δd and d0 are the convergence point offset and standard convergence distance respectively; p max is the maximum airflow pressure; coefficients: K2=0.3MPa / °, K4=0.2; reference value: d0=5mm (reference distance); intelligent compensation of powder feeding amount (to prevent element burnout): ΔVf=-K5×η×Vf+K6×dφ / dt; where ΔVf is the powder feeding amount compensation; coefficients: K5=1.8, K6=0.08g / (s·% / s); parameter: dφ / dt is the porosity change rate (% / s).

[0021] Step 2: Adaptive laser focus scanning monitors the distance change from the spray gun to the substrate surface in real time, calculates the focus compensation displacement, adjusts the axial position of the lens group through the piezoelectric ceramic driver to correct the focus position, and links with the process health index system to switch different working modes according to the coating thickness fluctuation; In the step of focusing powder pre-activation in a flat-top laser beam, a dynamic focus compensation mechanism is added: 201. Real-time surface topology monitoring: A laser displacement sensor (resolution 1 μm) is integrated at the end 11 to measure the distance change ΔH between the spray gun and the substrate surface in real time (sampling frequency 5 kHz); 203. Focus offset calculation: Based on the distance change ΔH and the preset distance d (2-10mm) of the powder convergence point, calculate the focus compensation displacement: ΔF = k1 × ΔH × (d / d0), where k1 = 0.8 is the thermal expansion coefficient, d0 = 5mm reference distance, and ΔH is the distance change from the spray gun to the substrate surface (measured in real time by the laser displacement sensor to reflect surface topology changes); 203. Dynamic focus adjustment: The axial position of the collimating and shaping lens group 6 is adjusted by a piezoelectric ceramic driver, with a displacement accuracy of ±0.5μm and a response time of <1ms. The focus position correction formula is: F new =F0+ΔF, where F0 is the initial focus position, F new is the new focus position after state adjustment, ΔF is the calculated focus compensation displacement; 204. Linked with the PHI system: When the process health index PHI>0.2, the focus scanning system is activated. When the coating thickness fluctuation is less than ±5μm, it switches to energy-saving mode (sampling frequency is reduced to 1kHz).

[0022] Step 3: Real-time diagnosis of lens abnormalities. Through dual-wavelength transmittance monitoring and thermal deformation wavefront diagnosis, a lens health index is constructed and a graded response is performed. When a lens abnormality occurs, corresponding measures such as early warning, power reduction, and emergency shutdown are taken. At the same time, the powder feeding rate is also adjusted in conjunction with the lens health index.

[0023] 301. Dual-wavelength transmittance monitoring: Add a reference light sensor (wavelength 635nm) at the entrance of the laser output head 1; add a monitoring light sensor (wavelength 1064nm) at the flat-top beam exit; calculate the transmittance T in real time ratio :T ratio =(P out / P in )×(λ ref / λ main ), where P out and P in are the output power measured by the monitoring light sensor (wavelength 1064nm), which is the power of the laser after passing through the system, and the input power measured by the reference light sensor (wavelength 635nm), which is the initial power of the laser before entering the system. ref =635nm is the reference light wavelength, λ main =1064nm as main laser wavelength); 302. Thermal deformation wavefront diagnosis: A Shack-Hartmann wavefront sensor is integrated in the conversion connector 7; Analyze the amount of beam wavefront distortion: in are the observed subaperture phase and the reference subaperture phase, respectively, N = 128, and the unit nm is the number of subapertures; 303. Abnormal index fusion and three-level warning: Constructing the lens health index (LHI): LHI=0.6×(1-T ratio )+0.4×(WFE / 50); The graded responses are shown in the graded response table:

[0024] 304. Powder feeding linkage: When LHI>0.3, the powder feeding amount is automatically reduced by 30% (to prevent the generation of unmelted particles); after the fault is eliminated, it is gradually restored according to Vf recovery = Vf0×[1-0.5×(LHIhistory)], where Vf0 is the initial reference powder feeding speed, and LHIhistory is the last recorded (or relevant historical period) lens health index (LHI) value before the fault is eliminated.

[0025] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A supersonic laser spraying device and method, characterized in that: include: Output optical fiber, collimating lens barrel (2), collimating lens group (3), converging lens (4), lens barrel (5), collimating shaping lens group (6), conversion connector (7), air inlet nozzle (8), light-powder coupling channel (9), Laval cavity (10), end (11), powder inlet nozzle (12), powder buffer cavity (13), annular powder inlet channel (14); The laser output head (1) is provided with a collimating lens barrel (2) at one end, a lens barrel (5) is provided at one end of the collimating lens barrel (2), a conversion connector (7) is provided at one end of the conversion connector (7), a Laval cavity (10) is provided at one end of the Laval cavity (10), an end head (11) is provided at one end of the Laval cavity (10), and a light-powder coupling channel (9) is provided in the end head (11); A collimating lens group (3) is symmetrically provided in one end of the collimating lens barrel (2), a converging lens (4) matched with the collimating lens group (3) is provided in one end of the lens barrel (5), and a collimating shaping lens group (6) is provided in the other end of the lens barrel (5); The conversion connector (7) is also provided with an air inlet nozzle (8); A powder buffer chamber (13) is provided in the end head (11), a powder inlet nozzle (12) communicating with the outside is provided on the powder buffer chamber (13), and an annular powder inlet channel (14) communicating with the light-powder coupling channel (9) is also provided in the powder buffer chamber (13); The laser output head (1), the collimating lens barrel (2), the lens barrel (5), the conversion connector (7), the Laval cavity (10), the end head (11) and the optical powder coupling channel (9) are interconnected.

2. The supersonic laser spraying device according to claim 1, characterized in that: The laser output head (1) is a QBH, LOE, LOC or Qplus structure; The collimating lens barrel (2) is used to install the collimating lens group (3) and the converging lens (4); The collimating lens group (3) is composed of 2-4 lenses and is used to collimate the divergent laser output by the laser output head (1); The converging lens (4) is used to convert the collimated laser into a converging beam; The lens barrel (5) is the lens barrel of the collimating shaping lens group (6); The collimating and shaping lens group (6) is used to convert the converged laser into a collimated beam with a diameter of 2 mm to 10 mm, and collimate the laser into a flat-top beam; The conversion connector (7) is used to connect the lens barrel (5) of the lens assembly and the Laval nozzle body at the rear; The gas inlet nozzle (8) is used to inject high-pressure argon gas; The light-powder coupling channel (9) is formed by connecting the end head (11) to the Laval nozzle through threads and the end head (11) to the Laval chamber (10) to form a powder buffer chamber (13) and an annular powder feed channel (14). The width of the annular powder feed channel is 0.5 mm to 1.5 mm. The annular powder feed channel is the light-powder coupling channel for spraying powder of the Laval nozzle. The Laval cavity (10) is the main body of the Laval nozzle of the spray gun, the inner cavity is a Laval structure, and the diameter of the thin diameter part is 2mm-10mm; high-pressure argon gas forms a supersonic airflow after passing through the thin diameter; The end head (11) is connected to the Laval nozzle via a thread; The powder feed nozzle (12) injects the spray powder using a powder feeder; The powder buffer chamber (13) is formed by connecting the end head (11) to the Laval nozzle through threads and the end head (11) and the Laval chamber (10) are connected in place; The annular powder feed channel (14) is formed after the end head (11) is connected to the Laval nozzle through threads and the end head (11) and the Laval chamber (10) are connected in place.

3. A method for applying a supersonic laser spraying device according to any one of claims 1 to 2, characterized in that: The following steps are involved: S1. Multi-parameter closed-loop dynamic control: Simultaneously monitor the three-dimensional temperature distribution of the molten pool, the powder flow divergence angle and convergence point offset, and the element burnout rate parameters to build a process health index. Based on the control trigger conditions, digital twin-driven parameter optimization is used to achieve dynamic adjustment of laser power, coordinated control of airflow pressure, and intelligent compensation of powder feed rate to reduce coating defects. S2, Adaptive Laser Focus Scanning: Real-time monitoring of the distance change between the spray gun and the substrate surface, calculation of focus compensation displacement, adjustment of the lens group axial position via the piezoelectric ceramic driver to correct the focus position, and linkage with the process health index system to switch to different working modes according to coating thickness fluctuations; S3. Real-time diagnosis of lens abnormalities: Through dual-wavelength transmittance monitoring and thermal deformation wavefront diagnosis, a lens health index is constructed and a graded response is performed. When a lens abnormality occurs, corresponding measures such as early warning, power reduction, and emergency shutdown are taken. At the same time, the powder feeding amount will also be adjusted in conjunction with the lens health index.

4. A supersonic laser spraying method according to claim 3, characterized in that: The specific operation steps of S1 are as follows:

101. Simultaneously monitor the temperature distribution of the molten pool, the offset between the powder flow divergence angle and the convergence point, and the element burnout rate; 102. Calculate the process health index (PHI) using the following expression: PHI = 0.4 × |temperature fluctuation rate| + 0.3 × divergence angle deviation rate + 0.3 × burnout rate deviation rate; control is triggered when PHI > 0.25 or element burnout rate > 2.5%; 103. Predicting porosity and bonding strength using long short-term memory neural network model; 104. Adaptive particle swarm optimization algorithm is used to solve the optimal laser power, air flow pressure and powder feeding rate; 105. Dynamic compensation execution: Adjust the laser power according to the difference between the average temperature of the molten pool and the target temperature and the temperature curvature; Adjust the airflow pressure according to the powder flow divergence angle and the offset of the convergence point; Adjust the powder feeding amount according to the element burnout rate and porosity change rate.

5. The supersonic laser spraying method according to claim 3, characterized in that: The specific operation steps of S2 are as follows: In the powder pre-activation step of focusing in the flat-top laser beam, a dynamic focus compensation mechanism is added, including:

201. Real-time surface topology monitoring: A laser displacement sensor is integrated at the end (11) to measure the distance change ΔH from the spray gun to the substrate surface in real time; Focus offset calculation: Based on the distance change ΔH and the preset distance d of the powder convergence point, calculate the focus compensation displacement: ΔF=k1×ΔH×(d / d0), where k1=0.8 is the thermal expansion coefficient, d is the preset distance of the powder convergence point, and the value is set between 2mm-10mm, d0=5mm reference distance, and ΔH is the distance change from the spray gun to the substrate surface; 203. Dynamic focus adjustment: The axial position of the collimating shaping lens group (6) is adjusted by the piezoelectric ceramic driver; the focus position correction formula is: F new =F0+ΔF, where F0 is the initial focus position, F new is the new focus position after state adjustment, ΔF is the calculated focus compensation displacement; 204. Linked with the PHI system: When the process health index PHI>0.2, the focus scanning system is activated. When the coating thickness fluctuation is less than ±5μm, it switches to energy-saving mode, that is, the sampling frequency is reduced to 1kHz.

6. The supersonic laser spraying method according to claim 3, characterized in that: The specific operation steps of S3 are as follows:

301. Calculate laser transmittance in real time through input power sensor and output power sensor; 302. Detecting the wavefront distortion of the laser beam in real time through a wavefront sensor; 303. Calculate the lens health index LHI based on the transmittance and wavefront distortion, and perform a graded response: When the LHI is in the range of 0.1 to 0.3, the optical system warning is triggered; When LHI is in the range of 0.3 to 0.5, reduce the laser power and start compressed air dust removal; When LHI is greater than 0.5, perform emergency shutdown and locate the faulty lens; 304. When LHI is greater than 0.3, the powder feeding amount will be automatically reduced; after the fault is eliminated, the powder feeding amount will gradually return to the initial value.

Images