A method of active agent assisted external field hybrid laser cleaning

Abstract

The application provides an active agent assisted external field composite laser cleaning method, according to diversified cleaning requirements of various cleaning materials, structures, environments and conditions, suitable active agent components are determined, the most effective external field type, the optimal process parameter, the best time and space coupling procedure and the most reasonable laser cleaning mode of the external field composite laser cleaning are determined, so that the diversified laser cleaning requirements of various cleaning objects are met, and the active agent assisted external field composite laser cleaning method with high efficiency, high quality, precision, economy, reliability and effectiveness is formed by organic integration of multiple factors.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of surface cleaning technology, in particular to a kind of active agent assisted external field composite laser cleaning method. BACKGROUND

[0002] In recent years, laser cleaning technology is widely applied in the field of surface and cleaning technology due to its green, non-contact, flexibility and high efficiency. Laser cleaning technology has many advantages, and is developing towards larger area, faster, more efficient, more precise and more complex.

[0003] At present, laser cleaning technology is developing rapidly and plays an important role in the national economy. However, in the face of difficult-to-clean metal materials such as titanium alloy and high-temperature alloy in the field of aerospace, the requirements of large-area cleaning efficiency and quality in the field of automobile, ship and oil and gas pipeline, laser cleaning technology has many problems and deficiencies: (1) the price of pulse laser and ultrafast laser equipment is high; (2) the energy loss of non-ferrous metal laser cleaning is large; (3) the laser cleaning efficiency is not high, and multiple cleaning is required; (4) the plasma laser shock wave cleaning process is strict and easy to damage the substrate; (5) particles generated during laser cleaning recontaminate the clean surface, causing secondary pollution; (6) there is a lack of effective cleaning method for difficult-to-clean materials and objects or in harsh environmental conditions.

[0004] Therefore, in addition to the development of advanced laser technology and the optimization of laser cleaning process parameters, how to use existing mature laser cleaning technology and equipment to achieve efficient, high-quality, precise and low-cost laser cleaning technology is the key scientific and technical problem to be solved.

[0005] A large number of studies have shown that laser and material or air interaction will produce plasma, and magnetic field, ultrasonic field has significant influence, constraint and control effect on the movement state of plasma, liquid formed by laser melting metal, solidification of molten fluid; At the same time, active agent contains elements with large atomic radius, strong electron affinity and surface activity. Studies have shown that active agent has the effect of restraining plasma, forcing plasma to contract, changing the plasma force, and can control the surface tension and flow state of liquid metal, thereby increasing the removal depth or melting depth. In addition, the replaced metal cations can also refine grains and improve surface microstructure, etc. Therefore, active agent has been widely used in welding, metallurgy, chemical industry and other fields. The above provides strong theoretical support and technical invention inspiration for the present application.

[0006] From the above, the advantages of active agents and external fields can be fully utilized. With the assistance of active agents, an external field composite laser cleaning technology based on ultrasonic fields and magnetic fields is designed. An active agent assisted external field composite laser cleaning method is formed to solve the key problems existing in the current laser cleaning field, which is beneficial to cleaning efficiency, no damage to the substrate, no secondary pollution, and reducing cleaning cost, and meets the cleaning needs of various materials and structures under harsh environmental conditions with high efficiency, high quality, and high precision.

[0007] A jet flow laser composite cleaning method and a cleaning system are disclosed in Chinese Patent Publication No. CN108526091B. Cavitation jet flow generates a water film on the surface of the workpiece, and the laser beam is focused in the water film to generate steam bubbles to impact the surface of the substrate, prolong the action of the cavitation jet flow, and remove solid particles with a diameter greater than 50nm on the surface of the workpiece, meeting the processing requirements of the wafer substrate surface. The patent uses pressurized form to realize cavitation jet flow, which is different from the innovative idea of using ultrasonic comprehensive effect in the present method, and the implementation effect also has differences.

[0008] Chinese Patent Publication No. CN114082717A discloses a device and a cleaning method for laser cleaning optical glass based on magnetic field and airflow assistance. Magnetic poles are installed on both sides of the surface to be processed to generate a magnetic field. The magnetic field and the auxiliary airflow work together to constrain and change the laser shock wave, and make it drift on the surface to be processed, expand the cleaning area, and improve the cleaning efficiency. However, the patent does not disclose many key details of the important magnetic field used, and the effect needs to be observed.

[0009] The literature (Liu Shiguang. Technical research on pulse laser cleaning of aluminum alloy surface paint coating. Shandong: Qingdao University of Technology, Master's Thesis, 2022) proposes an ultrasonic assisted laser two-step cleaning method, which further reduces the damage to the aluminum alloy surface substrate and obtains higher paint removal cleaning quality. However, the ultrasonic assisted laser cleaning technology results in a large loss of laser energy during ultrasonic assisted laser cleaning.

[0010] In the above invention, the laser cleaning technology needs to be improved and enhanced, and the characteristics of active agents, ultrasonic fields, and magnetic fields are not fully utilized. The cleaning objects and means used are limited, and corresponding and effective cleaning schemes cannot be designed according to the cleaning objects, conditions, environment, and special needs to form new cleaning technologies.

[0011] Through retrieval, it is found that there are few literatures on active agents + laser cleaning and active agents + external fields + laser cleaning. Therefore, the present invention proposes an active agent assisted external field composite laser cleaning method to solve the above problems. SUMMARY

[0012] To solve the above problems, the present application aims at making full use of the characteristics of active agents, ultrasound and magnetic field, and proposes an active agent assisted external field composite laser cleaning method, which interacts, influences and couples with each other and organically integrates the active agent, ultrasound field, magnetic field and cleaning laser beam to form various active agent assisted external field composite laser cleaning technologies suitable for diversified cleaning requirements of various cleaning materials, structures, environments and conditions, and to improve the effect of laser cleaning by designing corresponding, effective and cost-controllable cleaning schemes and technologies according to the cleaning materials, conditions, environments, structures and technical requirements.

[0013] The present application provides an active agent assisted external field composite laser cleaning method, which develops and determines suitable active agent components according to the diversified cleaning requirements of various cleaning materials, structures, environments and conditions, determines the most effective external field type, optimal process parameters, best time and space coupling procedure and most reasonable laser cleaning mode of the adaptive external field composite laser cleaning to meet the diversified laser cleaning requirements of various cleaning objects, and organically integrates multiple factors to form an active agent assisted external field composite laser cleaning method with high efficiency, high quality, precision, economy, reliability and effectiveness.

[0014] The present application is implemented as follows: an active agent assisted external field composite laser cleaning method, the external field is an ultrasound field, or a magnetic field, or a composite field of the ultrasound field and the magnetic field, the magnetic field is a longitudinal magnetic field or a transverse magnetic field, and the ultrasound wave is a longitudinal wave or a transverse wave; the external field includes three working states or modes of pre-treatment, cleaning and post-treatment.

[0015] The active agent is mainly composed of a plurality of compounds, and the main components include one or a mixture of two or more of chlorides, oxides, fluorides, metal elements, non-metal elements, organic solvents, distilled water and rare earths.

[0016] The laser cleaning is a dry laser cleaning method or a wet laser cleaning method.

[0017] The method comprises the following steps:

[0018] S1, determining the active agent component: the active agent uses a characteristic variable function Φi (i is an integer from 1 to m) to represent the distribution coefficient of m components (m≤30), and the active agent is composed of one or a mixture of two or more components, i.e. According to the material properties of the object to be cleaned and the comprehensive cleaning requirements thereof, a material calculation method, a machine learning method or a process experiment method is used to determine the reasonable active agent component, and the diameter of the active agent powder is 10-85 μm.

[0019] S2, determining the external field type: a characteristic variable function Γ j(j is 1, 2, 3) represents three types of external fields, ultrasonic emission devices are arranged around the top or surface or back of the metal to be cleaned to form an ultrasonic field Γ1, or excitation devices are arranged to form a magnetic field Γ2, or ultrasonic emission devices and excitation devices are used together to form a composite field of acoustic field and magnetic field Γ3, and the appropriate type of external field is determined according to the object to be cleaned and the comprehensive requirements of cleaning;

[0020] S3, determining the laser cleaning method: using the characteristic variable function δ k (k is 1, 2) represents two types of laser cleaning methods, a layer of suitable active agent is coated or sprayed on the surface of the metal object to be cleaned to form a dry laser cleaning method δ1, or a suitable active agent is added to the liquid to form a liquid film on the surface of the metal object to be cleaned to form a wet laser cleaning method δ2, and the appropriate laser cleaning method is determined according to the object to be cleaned and the comprehensive requirements of cleaning;

[0021] S4, determining the external field composite laser cleaning process: adjusting and optimizing the external field process parameters and the laser cleaning process parameters, and organically coupling to form the best external field composite laser cleaning process parameters, which are the reasonable process point values, or linear intervals or area ranges of the mutual matching of the external field and the laser;

[0022] The external field process parameters include ultrasonic field process parameters, or magnetic field process parameters, or composite field process parameters of ultrasonic field and magnetic field acting simultaneously;

[0023] The magnetic field process parameters include intermittent alternating magnetic field process parameters, or pulsed alternating magnetic field process parameters, or continuous alternating magnetic field process parameters, or rotating magnetic field process parameters, or constant magnetic field process parameters;

[0024] The laser cleaning process parameters include continuous laser cleaning process parameters, or pulsed laser cleaning process parameters, or ultrafast laser cleaning process parameters, or plasma laser shock wave cleaning process parameters;

[0025] S5, determining the external field and laser beam space-time coupling procedure: using the characteristic variable function Ψ t (t is 1, 2, 3, 4, 5) represents five types of external field and laser beam time coupling procedures, the order of the external field and the laser beam on the time coordinate axis of the object to be cleaned is designed according to the object to be cleaned, and the relative time order relationship of the coupling of the external field and the laser beam is determined through comprehensive evaluation to form the coupling procedure, which is the coupling procedure Ψ1 of the external field applied in advance to the cleaning laser beam, or the coupling procedure Ψ2 of the external field and the laser beam applied simultaneously, or the coupling procedure Ψ3 of the external field and the laser beam applied subsequently, or the coupling procedure Ψ4 of the external field and the laser beam delayed and continued to act, or the combined coupling procedure Ψ5 between the above two procedures, so as to ensure the cleaning efficiency and the cleaning quality.

[0026] According to the specific real-time position and cleaning direction of the object to be cleaned, a physical reference coordinate system is established for the front and rear space, and a characteristic variable function β s (s is 1, 2, 3) represents three types of external field and laser beam spatial position coupling process, and the coupling process is an external field pre-coupling process β1, or a coaxial coupling process β2, or a post-coupling process β3;

[0027] S6, determining the cleaning threshold and damage threshold, optimizing the active agent assisted external field composite laser cleaning process: using surface topography and microstructure detection technology, determining the cleaning standard of completely cleaning without damaging the substrate, and determining the minimum threshold and damage threshold of the active agent assisted external field composite laser cleaning based on this, optimizing and perfecting the active agent assisted external field composite laser cleaning process and its parameters, using a characteristic function f(x) to represent the characteristics of the active agent assisted external field composite laser cleaning process, wherein x includes characteristic variables Фi, Γ j , δ k , Ψ t , β s All five characteristic variables have That is, f(x) is a combination of the five characteristic variables;

[0028] S7, using the active agent assisted external field composite laser cleaning method to clean the object: using the most effective active agent component Фi, the most reasonable external field type Γ j , the most appropriate laser cleaning mode δ k , the best coupling process Ψ t and β s , the optimal process parameters f(x) to effectively clean the object to be cleaned, and the organic integration of multiple factors constitutes an efficient, high-quality, precise and economical active agent assisted external field composite laser cleaning method.

[0029] For the determination of active agent components, external field types, coupling processes, and laser cleaning methods:

[0030] 1) When the cleaning difficulty is great, the precision is high, the performance is high, the area is very large, there are environmental protection requirements, there is no cost requirement, and the material itself is difficult to clean, the active agent assisted external field composite laser cleaning method of rare earth reinforced active agent Фi+ composite field of sound field and magnetic field Γ3 mode+ combination type coupling process Ψ5+ post-coupling process β3+ wet pulse laser cleaning mode δ2 is adopted;

[0031] 2) When the precision, performance requirements are general, cleaning area is medium, there is low cost requirements, the material itself is not difficult to clean, using chloride or oxide component of active agent Фi + ultrasonic field Γ1 mode + while applying coupling process Ψ2 + coaxial coupling process β2 + dry pulse laser cleaning way δ1 active agent assisted external field composite laser cleaning method;

[0032] 3) When the precision, performance requirements are low, efficiency requirements are high, cleaning area is medium, the material itself is generally difficult to clean, the cost requirements are general, using oxide or fluoride component of active agent Фi + alternating magnetic field Γ2 mode + coupling process Ψ1 + coaxial coupling process β 2+ dry continuous laser cleaning way δ1 active agent assisted external field composite laser cleaning method;

[0033] 4) When high performance, high efficiency, high quality, high precision are required, the cleaning area is large, the cost requirements are moderate, and the material cleaning difficulty is medium, the rare earth enhanced active agent Фi + the composite field Γ3 mode of sound field and magnetic field + the coupling process Ψ4 of delayed continuous action + the active agent assisted external field composite laser cleaning method of post-coupling process β 3+ wet pulse laser cleaning way δ2 active agent assisted external field composite laser cleaning method;

[0034] 5) When the cleaning object is particulate matter or organic paint, there are strict requirements for no substrate burning, high efficiency, high quality and high precision, the active agent is added to the liquid, the double mode of pre-treatment and post-treatment of ultrasonic field and magnetic field is used, the cavitation and activation of active agent water jet to the surface to be cleaned, the composite field mode Γ3 of ultrasonic field and intermittent alternating magnetic field coupling is used, and the active agent assisted external field composite laser cleaning method of wet plasma shock wave laser cleaning way;

[0035] 6) When there are strict requirements on the stability of the cleaning process, the surface topography after cleaning, the residual stress state, the corrosion resistance, the substrate burning, the defects, the efficiency and the weldability, the active agent of multiple components combined with rare earth or graphene enhancement is used, the ultrasonic field and pulse alternating magnetic field, or the ultrasonic field and intermittent alternating magnetic field are simultaneously added to the whole cleaning process, the ultrasonic and magnetic field adopts the double working mode of pre-treatment and post-treatment, and the external field uses changeable and appropriate process parameters in pre-treatment, cleaning and post-treatment;

[0036] 7) When the metal material is particularly difficult to clean or the fine structure is particularly complex, the active agent is added to the liquid to form a water jet to the surface to be cleaned, the ultrasonic field and the magnetic field are used simultaneously, applied in advance and delayed, so that the ultrasonic field also cavitates and activates the active agent during cleaning, the parameters of the ultrasonic field applied in advance and the magnetic field can be changed to adapt to the pre-treatment requirements, the cleaning parameters of the external field are different from the pre-treatment parameters of the external field, and the pulse or ultrafast laser process is used for cleaning;

[0037] 8) When cleaning organic or inorganic objects in a low-temperature underwater environment, the active agent is sprayed on the surface of the object to be cleaned, the local area to be cleaned is heated in advance using a high-power ultrasonic field, the temperature of the local area to be cleaned is raised to a suitable cleaning condition, and the active agent is uniformly distributed in the local area to be cleaned, then the ultrasonic field process parameters are adjusted to be suitable for the underwater cleaning mode of the ultrasonic-magnetic field coupled laser beam, and a high-power continuous laser process is used for the whole cleaning process, forming an active agent assisted variable external field process composite laser cleaning method;

[0038] Further, the active agent assisted external field composite laser cleaning method uses machine learning method, which is a method of machine learning assisted determination of reasonable active agent composition, including establishing a prediction model of active agent composition-cleaning depth-surface roughness-cleaning threshold of laser cleaning based on machine learning model, determining the prediction model of the most suitable active agent composition effect by comparing the performance and behavior of multiple machine learning models such as multilayer perception model, or random forest model, or K-nearest neighbor model, or support vector machine model, analyzing the influence law of active agent composition and external field composite laser cleaning process on the surface appearance, surface quality, surface performance and surface organization of the object to be cleaned, and providing the most suitable design scheme and the most scientific external field composite laser cleaning process matching parameters for the selection of effective active agent composition for efficient, high-quality, precise and low-cost laser cleaning;

[0039] The data set is established by various processing purposes of active agent composition and material properties of laser cleaning object. The active agent includes single-element active agent, halide active agent, oxide active agent or composite active agent, and the main components include CaF2, MgF2, NaF, ALF3, MnCl2, CaCl2, MnCl2, CdCl2, ZnCl2, MgCl2, NiCl2, CaO, V2O5, SiO2, TiO2, MnO2, Al2O3, MgO, Cr2O3, B203, CuO, NiO, Nd2O3, Y2O3, La2O3, CeO, Ni, Al, Zn, Si, Te, Cr, Cd, Nb, V, graphene, C, one of rare earth, or a mixture of two or more;

[0040] The cleaning quality involves surface roughness, cleaning depth and cleaning threshold, the model input layer variable is 10, and the output layer variable is three: surface roughness, cleaning depth and cleaning threshold;

[0041] The cleaning surface quality parameters are obtained by detection means, the data set is expanded by experiments and existing literature data, the missing data records are 0, and the active agent database is established after data normalization, not less than 300 groups;

[0042] The Pearson coefficient is calculated and analyzed, and one of the machine learning models of multilayer perception, random forest, K-nearest neighbor, support vector machine, back propagation neural network and Bayesian ridge regression is established respectively; the normalized data set is divided into training set and test set; in order to prevent over fitting, early stopping method is adopted;

[0043] The root mean square error RMSE, mean absolute percentage error MAPE and decisive coefficient R of each model are calculated 2 After training, the model is tested using the test set;

[0044] The prediction results are normalized to convert them into regular data format; by drawing a scatter plot, the experimental value and the predicted value of the test set are compared to evaluate the prediction ability of each model, and based on these indicators, the composition ratio parameter of the active agent composition that best predicts the performance of the external field composite laser cleaning quality is determined.

[0045] Further, the active agent assisted external field composite laser cleaning method, the cleaning object is the rust layer of ship steel plate AH36, the area is very large, and it has the requirements of low cost, high efficiency, environmental protection, weldability and general precision, the process of active agent assisted external field composite laser cleaning is: the external field uses a composite field of ultrasonic and magnetic field acting at the same time, the ultrasonic is a pre-applied coupling process, and the magnetic field is a simultaneously applied coupling process, the ultrasonic is located in the front space position of the laser beam, the magnetic field and the laser beam are coaxial in space position, and the active agent assisted external field composite laser cleaning method using continuous laser cleaning mode;

[0046] The active agent composition is composed of 31% SiO2, 28.5% TiO2, 26% MnO2 and 14.5% graphene with a particle diameter of 30-45 μm, and the corresponding auxiliary reagent is added and mixed with distilled water, the active agent liquid is guided to the surface of the rust through the catheter equipped with an ultrasonic wave generating device to form a liquid film, and the active agent liquid is simultaneously cavitated and activated by ultrasonic wave, as shown in Figure 2 ;

[0047] The external pulse alternating longitudinal magnetic field strength is 0.12T, the magnetic field frequency is 0.8KHz, the continuous laser cleaning power is 650W, the continuous laser cleaning frequency is 256Hz, the ultrasonic power is 650W, and the ultrasonic frequency is 20Khz; the cleaning efficiency is improved by more than 28%, the surface quality is improved by more than 24%, the cost is reduced by more than 10%, and the laser cleaning threshold is reduced by more than 20%.

[0048] Further, the active agent assisted external field composite laser cleaning method, the cleaning object is the surface of the nuclear stainless steel 00Cr19Ni10, the medium area to be cleaned has the requirements of high efficiency, environmental protection, weldability, high precision, high quality, no cost requirements, the process of the active agent assisted external field composite laser cleaning is: the external field uses the composite field of ultrasonic and magnetic field acting at the same time, the ultrasonic and magnetic field are coupled procedures applied at the same time, the ultrasonic is located in the front space position of the laser beam, the magnetic field is coaxial with the laser beam, the active agent assisted external field composite laser cleaning method using pulsed laser cleaning mode;

[0049] The active agent component is obtained by grinding and mixing 22% Cr2O3, 15% SiO2, 21% TiO2, 13% Al2O3, 12% NaF, 7% Nd2O3 and 10% graphene with a particle diameter of 30-45 μm, adding appropriate auxiliary reagents, and coating the active agent on the surface of the nuclear stainless steel 00Cr19Ni10.

[0050] 99.99% argon protection, argon flow rate 16-22 L / min, additional pulsed alternating longitudinal magnetic field strength 0.15 T, magnetic field frequency 1.2 KHz, pulsed laser cleaning power 100 W, pulsed laser repetition frequency 80 KHz, ultrasonic power 820 W, ultrasonic frequency 24 KHz; the cleaning efficiency is increased by more than 18%, the surface performance is increased by more than 12%, and the laser cleaning threshold is reduced by more than 15%.

[0051] Optionally, in the active agent assisted external field composite laser cleaning, the magnetic field is generated by a coil, the energized coil uses a hollow coil, the hollow coil is a spiral winding coil, the coil has an embedded iron core and a cooling structure, the cooling structure ensures that the coil can work normally in high temperature environment, and the hollow coil is installed around the workpiece to be cleaned.

[0052] Optionally, the ultrasonic field is generated by an ultrasonic wave generating device, which includes an ultrasonic wave generator, an ultrasonic vibration head and a clamping device, the ultrasonic vibration head is integrated near the laser head and has a certain distance from the cleaning position to prevent the laser beam from damaging the ultrasonic vibration head; the excitation coil and the ultrasonic vibration head form an integrated structure device of external field-workpiece-cleaner, thereby constructing the active agent assisted external magnetic field composite laser cleaning method.

[0053] Optionally, in the active agent assisted external field composite laser cleaning, the waveform, direction, frequency and amplitude of the excitation current can be adjusted or set, and the power, frequency, direction, waveform and distance of the ultrasonic can be adjusted or set; the magnetic field parameters and the ultrasonic field parameters can be adjusted or set to use adaptive variable parameters and variable types for cleaning work in the pre-treatment, cleaning and post-treatment working states or modes.

[0054] Optionally, the active agent assisted external field complex laser cleaning method, the active agent is to reduce the surface tension of the metal interface, change the interface properties and state of the metal laser cleaning, through the influence of the active agent on the surface performance of the micro-melt pool during laser cleaning, reduce the cleaning threshold, increase the cleaning depth, improve the cleaning surface quality, and improve the cleaning efficiency; at the same time, the interaction of ultrasonic field, magnetic field and plasma during laser cleaning can effectively increase the absorption rate of laser energy on the metal surface, also can improve the laser cleaning depth, improve the cleaning efficiency; the additional ultrasonic and magnetic field has magnetic comprehensive effect, magnetic field metallurgical treatment effect, magnetic field stirring effect, ultrasonic restraint comprehensive effect, ultrasonic cavitation effect, ultrasonic temperature rise effect when the metal is melted during laser cleaning, reduces the loss of laser energy of the metal, significantly reduces the cleaning threshold, so that the laser cleaning power and difficulty can be reduced, and good cleaning effect can be obtained; therefore, the interaction of active agent, ultrasonic field, magnetic field and laser beam can effectively improve the cleaning efficiency and quality of the metal surface; it can be used for cleaning of low carbon steel, alloy steel, stainless steel, armor steel, bearing steel, die steel, aluminum alloy, titanium alloy, magnesium alloy, copper alloy, high temperature alloy, refractory metal and surface attachments or oxides thereof.

[0055] Beneficial effects:

[0056] 1. The external magnetic field can effectively control the laser beam to produce plasma plume on the surface of the workpiece, increase the intensity of the laser plasma shock wave, improve the laser cleaning depth, and increase the laser cleaning effect and cleaning efficiency.

[0057] 2. The external magnetic field can control the aggregation and diffusion of laser plasma, reduce the shielding effect of plasma on laser, control the eruption period and intensity of plasma, change the distribution of plasma, make the distribution of laser energy more uniform, and effectively improve the stability of cleaning laser.

[0058] 3. The external magnetic field has the effects of magnetic melting and metallurgy. For metal materials, the magnetic field not only changes the state of plasma, but also changes the organization of metal materials, enhances the surface mechanical properties and weldability, reduces the minimum cleaning threshold of the cleaning object, improves the cleaning effect and efficiency, and saves the energy required for laser cleaning.

[0059] 4. The external ultrasonic field can produce cavitation, temperature rise, vibration and restraint effect. The ultrasonic field can restrain the laser beam plasma, so that the plasma produces agglomeration, strengthens the impact force and action range of the plasma, increases the temperature rise of the local area to be cleaned, and activates the liquid film, homogenizes the active agent, vibrates, separates and carries away the particulate matter, which is beneficial to the rapid peeling of the surface layer to be cleaned and prevents secondary particle deposition pollution.

[0060] 5. Surfactants have beneficial effects during cleaning. They contain a large number of surface-active elements with large atomic radii and strong electron affinity. Surfactants have the effect of confining plasma, forcing plasma to contract, changing plasma forces, and controlling the surface tension and flow state of liquid metal, thereby increasing the removal depth or melting depth. Moreover, the metal cations that are replaced can also refine grains and improve surface microstructure. At the same time, for organic coatings, appropriate surfactants can emulsify, soften, weaken, degrade, and adsorb organic coatings, reduce the binding force of organic coatings, and promote the peeling and cleaning of organic coatings.

[0061] 6. This invention fully utilizes the characteristics of surfactants, magnetic fields, and ultrasonic fields, and is applicable to various cleaning targets such as rust, coatings, oxide layers, particles, and organic matter. It provides corresponding and effective cleaning solutions based on the cleaning materials, structures, conditions, environment, and cost requirements, thereby improving the laser cleaning effect.

[0062] 7. The present invention adopts an active agent-assisted external field composite plasma shock wave laser cleaning method to achieve an effective cleaning method with a distance of more than 3mm between the laser beam and the surface of paint coatings, oil films, etc., forming a non-contact, non-direct cleaning mode, which is less likely to damage the substrate, reduces the process difficulty of plasma shock wave laser cleaning, and expands the technical application scope of plasma shock wave laser cleaning of organic coatings.

[0063] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Attached Figure Description

[0064] Figure 1 This is a flowchart of the surfactant-assisted external field composite laser cleaning method of the present invention.

[0065] Figure 2 This is a schematic diagram of the surfactant-assisted external field composite laser cleaning method of the present invention.

[0066] Figure 3 This is a schematic diagram of the surfactant-assisted external field composite plasma shock wave laser cleaning method of the present invention.

[0067] Figure 4 This is a comparison diagram of carbon steel samples using the two cleaning methods of the present invention.

[0068] Figure 5 This is a comparison diagram of alloy steel samples using the two cleaning methods of this invention.

[0069] Figure 6 These are comparative images of the surface morphology of alloy steel samples cleaned using the two cleaning methods of this invention.

[0070] Fig. 1: 1 laser beam; 2 surface of object to be cleaned; 3 substrate; 4 cleaning product; 5 plasma or plasma shock wave; 6 magnetic field; 7 ultrasonic vibration head; 8 liquid active agent conduit; 9 active agent; 10 plasma controlled rotational motion; 11 ordinary laser cleaning sample; 12 active agent assisted external field combined laser cleaning sample. DETAILED DESCRIPTION

[0071] The embodiments of the present application will be further described in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application but cannot be used to limit the scope of the present application. Figures 1-6

[0072] In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more; the term "+" means the organic integration of two or more factors, or conditions, or elements, or methods, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply the simple addition, or stacking, or mechanical combination of the factors, or conditions, or elements, or methods referred to, and cannot be understood as a limitation of the present application. The "or" in the specification and claims means at least one of the connected objects. The specific meaning of the above terms in the present application can be understood according to the specific circumstances for those skilled in the art.

[0073] Example:

[0074] An active agent assisted external field combined laser cleaning method, as shown in Fig. 1, comprises the following steps: Figure 1

[0075] S1, determining the active agent composition: the active agent uses a characteristic variable function Φi (i is an integer from 1 to m) to represent the distribution coefficient of m components (m≤30), and the active agent is composed of one, or two, or more than two components, i.e. According to the material properties of the object to be cleaned and the comprehensive requirements of its cleaning, a material calculation method, or a machine learning method, or a process experimental method is used to determine the reasonable active agent composition, and the diameter of the active agent powder is 10-85 μm;

[0076] S2, determining the type of external field: a characteristic variable function Γ j (j is 1, 2, 3) represents three types of external fields, ultrasonic emission devices are arranged on the upper part, or the surface, or the back of the metal to be cleaned to form an ultrasonic field Γ1, or excitation devices are arranged to form a magnetic field Γ2, or ultrasonic emission devices and excitation devices are used together to form a combined field of acoustic field and magnetic field Γ3, and according to the object to be cleaned and the comprehensive requirements of its cleaning, the appropriate type of external field is determined;

[0077] S3, determining the laser cleaning method: a characteristic variable function δ k ​​(k is 1, 2) represents two laser cleaning methods, a layer of suitable active agent is coated or sprayed on the surface of the metal object to be cleaned to form a dry laser cleaning method δ1, or a suitable active agent is added to the liquid to form a liquid film on the surface of the metal object to be cleaned to form a wet laser cleaning method δ2, and the suitable laser cleaning method is determined according to the object to be cleaned and the comprehensive requirements of cleaning;

[0078] S4, determining the external field combined laser cleaning process: adjusting and optimizing the external field process parameters and the laser cleaning process parameters, and organically coupling to form the best external field combined laser cleaning process parameters, which are reasonable process point values, or linear intervals or area ranges of mutual matching of the external field and the laser;

[0079] The external field process parameters include ultrasonic field process parameters, or magnetic field process parameters, or combined field process parameters of ultrasonic field and magnetic field;

[0080] The magnetic field process parameters include intermittent alternating magnetic field process parameters, or pulsed alternating magnetic field process parameters, or continuous alternating magnetic field process parameters, or rotating magnetic field process parameters, or constant magnetic field process parameters;

[0081] The laser cleaning process parameters include continuous laser cleaning process parameters, or pulsed laser cleaning process parameters, or ultrafast laser cleaning process parameters, or plasma laser shock wave cleaning process parameters;

[0082] S5, determining the external field and laser beam space-time coupling procedure: adopting a characteristic variable function Ψ t (t is 1, 2, 3, 4, 5) represents five types of external field and laser beam time coupling procedures, the order of the external field and the laser beam on the time coordinate axis of the object to be cleaned is designed according to the object to be cleaned, the relative time order relationship of the coupling of the external field and the laser beam is determined through comprehensive evaluation results to constitute the coupling procedure, the coupling procedure is the coupling procedure Ψ1 of the external field applied in advance to the cleaning laser beam, or the coupling procedure Ψ2 of the simultaneous application, or the coupling procedure Ψ3 of the subsequent application, or the coupling procedure Ψ4 of the delayed continuous action, or the combined coupling procedure Ψ5 between the above two procedures, so as to ensure the cleaning efficiency and the cleaning quality;

[0083] According to the specific real-time position and the cleaning direction of the object to be cleaned, a front and rear space physical reference coordinate system is adopted, and a characteristic variable function β s (s is 1, 2, 3) represents three types of external field and laser beam space position coupling procedures, and the coupling procedure is the front coupling procedure β1 of the external field to the cleaning laser beam, or the coaxial coupling procedure β2, or the rear coupling procedure β3;

[0084] S6, determining cleaning threshold and damage threshold, optimizing active agent assisted external field composite laser cleaning process: adopting surface topography and microstructure detection technology, determining cleaning standard of completely cleaned and not damaging substrate, on this basis, determining minimum threshold and damage threshold of active agent assisted external field composite laser cleaning, optimizing and perfecting active agent assisted external field composite laser cleaning process and parameters between minimum threshold and damage threshold, adopting characteristic function f(x) to represent active agent assisted external field composite laser cleaning process characteristic, wherein x includes characteristic variables Фi, Γ j , δ k , Ψ t , β s All 5 characteristic variables have That is, f(x) is a plurality of combinations of the 5 characteristic variables;

[0085] S7, cleaning object by adopting active agent assisted external field composite laser cleaning method: adopting most effective active agent component Фi, most reasonable external field type Γ j , most appropriate laser cleaning mode δ k , best coupling procedure Ψ t and β s , optimal process parameters f(x) of active agent assisted external field composite laser cleaning, effectively cleaning the object to be cleaned, and multi-factor organic integration constitutes an efficient, high-quality, precise and economical active agent assisted external field composite laser cleaning method.

[0086] For determination of active agent component, external field type, coupling procedure and laser cleaning mode:

[0087] 1) when the cleaning difficulty is great, the precision and performance are high, the area is very large, there is environmental protection requirement, there is no cost requirement, and the material itself is difficult to clean, the active agent assisted external field composite laser cleaning method of non-halide component rare earth reinforced active agent Фi+ composite field of sound field and magnetic field Γ3 mode+ combination type coupling procedure of advance application and delayed continuous action Ψ5+ post coupling procedure β3+ wet pulse laser cleaning mode δ2 is adopted;

[0088] 2) when the precision and performance requirements are general, the cleaning area is medium, there is low cost requirement, and the material itself is not difficult to clean, the active agent assisted external field composite laser cleaning method of chloride or oxide component active agent Фi+ ultrasonic field Γ1 mode+ simultaneous coupling procedure Ψ2+ coaxial coupling procedure β2+ dry pulse laser cleaning mode δ1 is adopted;

[0089] 3) when the precision and performance requirements are low, the efficiency requirement is high, the cleaning area is medium, the material itself is generally difficult to clean, and the cost requirement is general, the active agent assisted external field composite laser cleaning method of oxide or fluoride component active agent Фi+ alternating magnetic field Γ2 mode+ advance application coupling procedure Ψ1+ coaxial coupling procedure β 2+Active agent assisted external field combined laser cleaning method of dry continuous laser cleaning mode δ1;

[0090] 4) When high performance, high efficiency, high quality, high precision, large cleaning area, moderate cost, and medium difficulty of material cleaning are required, the active agent Фi+sound field and magnetic field combined field Γ3 mode+delayed continued action coupling process Ψ4+post-coupling process β are used. 3+ Active agent assisted external field combined laser cleaning method of wet pulse laser cleaning mode δ2;

[0091] 5) When the cleaning object is particulate matter or organic paint, and there are strict requirements for no substrate burning, high efficiency, high quality, and high precision, the active agent is added to the liquid, and the double mode of pre-treatment and post-treatment of ultrasonic field and magnetic field is used, so that the cavitation and activated active agent water jet reaches the surface to be cleaned, and the active agent assisted external field combined laser cleaning method of ultrasonic field and intermittent alternating magnetic field coupling combined field mode Γ3, wet plasma shock wave laser cleaning mode is used; as shown in Figure 3 .

[0092] 6) When there are strict requirements on the stability of the cleaning process, the surface topography after cleaning, the residual stress state, the corrosion resistance, the substrate burning, the defects, the efficiency, and the weldability, a rare earth or graphene enhanced multi-component combined active agent is used, and the ultrasonic field and pulse alternating magnetic field, or the ultrasonic field and intermittent alternating magnetic field are simultaneously added to the whole cleaning process. The ultrasonic and magnetic fields use a double working mode of pre-treatment and post-treatment, and the external field uses changeable and appropriate process parameters in pre-treatment, cleaning, and post-treatment;

[0093] 7) When it is particularly difficult to clean metal materials or particularly complex fine structures, the active agent is added to the liquid to form a water jet to the surface to be cleaned, the ultrasonic field and the magnetic field are used simultaneously, applied in advance, and delayed to continue to act, so that the ultrasonic field also cavitates and activates the active agent during cleaning. The ultrasonic field parameters and the magnetic field parameters can be changed in advance to meet the needs of pre-treatment, the external field cleaning parameters are different from the external field pre-treatment parameters, and the pulse or ultrafast laser process is used for cleaning;

[0094] 8) When cleaning organic or inorganic objects in underwater low-temperature environment, the active agent is sprayed on the surface of the object to be cleaned, a high-power ultrasonic field is used to preheat the local area to be cleaned, the temperature of the local area to be cleaned is raised to a suitable condition for cleaning, and the active agent is uniformly distributed in the local area to be cleaned. Then adjust the ultrasonic field process parameters to adapt to the underwater cleaning mode of ultrasonic-magnetic field coupled laser beam, and use a high-power continuous laser process to clean the whole process, forming an active agent assisted variable external field process combined laser cleaning method;

[0095] Further, the active agent assisted external field composite laser cleaning method adopts a machine learning method. The machine learning method is a method for assisting in determining reasonable active agent components. The method includes establishing a prediction model of active agent components-cleaning depth-surface roughness-cleaning threshold of laser cleaning based on a machine learning model. The performance and behavior of multiple machine learning models, such as a multi-layer perception model, or a random forest model, or a K-nearest neighbor model, or a support vector machine model, are calculated and compared to determine the prediction model of the most suitable active agent component effect. The influence law of the active agent component and the external field composite laser cleaning process on the surface appearance, surface quality, surface performance, and surface organization of the object to be cleaned is analyzed. An optimal design scheme for selecting effective active agent components and the most scientific external field composite laser cleaning process matching parameters are provided for efficient, high-quality, precise, and low-cost laser cleaning.

[0096] The data set is established by various processing active agent components and material properties of laser cleaning objects. The active agent includes a single-element active agent, or a halide active agent, or an oxide active agent, or a composite active agent. The main components include CaF2, MgF2, NaF, ALF3, MnCl2, CaCl2, MnCl2, CdCl2, ZnCl2, MgCl2, NiCl2, CaO, V2O5, SiO2, TiO2, MnO2, Al2O3, MgO, Cr2O3, B203, CuO, NiO, Nd2O3, Y2O3, La2O3, CeO, Ni, Al, Zn, Si, Te, Cr, Cd, Nb, V, graphene, C, one of rare earth, or a mixture of two or more.

[0097] The cleaning quality involves surface roughness, cleaning depth, and cleaning threshold. The model input layer variable is 10, and the output layer variable is three: surface roughness, cleaning depth, and cleaning threshold.

[0098] The cleaning surface quality parameters are obtained by detection means. Through experiments and the collection of existing literature, the data set is expanded, and the missing data records are 0. After data normalization, an active agent database with no less than 300 groups is established.

[0099] The Pearson coefficient is calculated and analyzed, and one of the machine learning models of multi-layer perception, random forest, K-nearest neighbor, support vector machine, back propagation neural network, and Bayesian ridge regression is established. The data set after normalization is divided into a training set and a test set. To prevent overfitting, an early stopping method is used.

[0100] The root mean square error RMSE, the mean absolute percentage error MAPE, and the decision coefficient R of each model are calculated 2 After training is completed, the test set is used to test the model.

[0101] The prediction results are normalized to convert them into a conventional data format. By drawing a scatter plot, the experimental values and the predicted values of the test set are compared to evaluate the prediction ability of each model, and based on these indicators, the composition ratio parameters of the active agent component that best predicts the performance of the field composite laser cleaning quality are determined.

[0102] Further, the active agent assisted field composite laser cleaning method, the cleaning object is the rust layer of ship steel plate AH36, the area is very large, and there are requirements of low cost, high efficiency, environmental protection, weldability, general precision, the process of active agent assisted field composite laser cleaning is: the field uses a composite field of ultrasonic and magnetic field acting simultaneously, the ultrasonic is a pre-applied coupling process, and the magnetic field is a simultaneously applied coupling process, the ultrasonic is located in the front space position of the laser beam, the magnetic field is coaxial with the laser beam, and the active agent assisted field composite laser cleaning method using continuous laser cleaning mode is used.

[0103] The active agent component is obtained by grinding and mixing 31% SiO2, 28.5% TiO2, 26% MnO2 and 14.5% graphene with a particle diameter of 30-45 μm, adding corresponding auxiliary reagents and mixing with distilled water, guiding the active agent liquid to form a liquid film on the surface of the rust through the catheter installed with the ultrasonic wave generating device, and simultaneously ultrasonic cavitation and activation of the active agent liquid, as shown in Figure 2 ;

[0104] The applied pulse alternating longitudinal magnetic field strength is 0.12 T, the magnetic field frequency is 0.8 KHz, the continuous laser cleaning power is 650 W, the continuous laser cleaning frequency is 256 Hz, the ultrasonic power is 650 W, and the ultrasonic frequency is 20 KHz; the cleaning efficiency is increased by more than 28%, the surface quality is increased by more than 24%, the cost is reduced by more than 10%, and the laser cleaning threshold is reduced by more than 20%.

[0105] Further, the active agent assisted field composite laser cleaning method, the cleaning object is the surface of nuclear stainless steel 00Cr19Ni10, the area to be cleaned is medium, and there are requirements of high efficiency, environmental protection, weldability, high precision, high quality, and no cost requirements, the process of active agent assisted field composite laser cleaning is: the field uses a composite field of ultrasonic and magnetic field acting simultaneously, the ultrasonic and the magnetic field are simultaneously applied coupling processes, the ultrasonic is located in the front space position of the laser beam, the magnetic field is coaxial with the laser beam, and the active agent assisted field composite laser cleaning method using pulse laser cleaning mode is used.

[0106] The active agent component is obtained by grinding and mixing 22% Cr2O3, 15% SiO2, 21% TiO2, 13% Al2O3, 12% NaF, 7% Nd2O3 and 10% graphene with a particle diameter of 30-45 μm, adding corresponding auxiliary reagents, and coating the active agent on the surface of the nuclear stainless steel 00Cr19Ni10.

[0107] 99.99% argon protection, argon flow rate 16-22 L / min, plus pulsed alternating longitudinal magnetic field strength 0.15 T, magnetic field frequency 1.2 KHz, pulsed laser cleaning power 100 W, pulsed laser repetition frequency 80 KHz, ultrasonic power 820 W, ultrasonic frequency 24 KHz; cleaning efficiency increased by more than 18%, surface performance increased by more than 12%, laser cleaning threshold reduced by more than 15%.

[0108] Optionally, the active agent assisted external field composite laser cleaning, the magnetic field is generated by a coil, the energized coil uses a hollow coil, the hollow coil is a spiral winding coil, the coil has an embedded iron core and a cooling structure, the cooling structure ensures that the coil can work normally in high temperature environment, and the hollow coil is installed around the workpiece to be cleaned;

[0109] Optionally, the ultrasonic field is generated by an ultrasonic wave generating device, which includes an ultrasonic wave generator, an ultrasonic vibration head, and a clamping device, the ultrasonic vibration head is integrated near the laser head and has a certain distance from the cleaning position to prevent the laser beam from damaging the ultrasonic vibration head; the excitation coil and the ultrasonic vibration head form an external field-workpiece-cleaner integrated overall structural device, thereby constructing an active agent assisted external magnetic field composite laser cleaning mode;

[0110] Optionally, the active agent assisted external field composite laser cleaning, the waveform, direction, frequency and amplitude of the excitation current can be adjusted or set, and the power, frequency, direction, waveform and distance of the ultrasonic wave can be adjusted or set; the magnetic field parameters and the ultrasonic field parameters can be adjusted or set to use adaptive variable parameters and variable types for cleaning work in the pre-treatment, cleaning and post-treatment working states or modes.

[0111] Optionally, the active agent assisted external field combined laser cleaning method, the active agent is to reduce the surface tension of the metal interface, change the interface properties and state of the metal laser cleaning, through the influence of the active agent on the surface properties of the micro-melt pool during laser cleaning, reduce the cleaning threshold, increase the cleaning depth, improve the cleaning surface quality, and improve the cleaning efficiency; at the same time, the interaction of ultrasonic field, magnetic field and plasma during laser cleaning can effectively increase the absorption rate of laser energy on the metal surface, and also can improve the laser cleaning depth and improve the cleaning efficiency; the additional ultrasonic and magnetic field has magnetic comprehensive effect, magnetic field metallurgical treatment effect, magnetic field stirring effect, ultrasonic restraint comprehensive effect, ultrasonic cavitation effect and ultrasonic temperature rise effect when the metal is melted during laser cleaning, which reduces the loss of laser energy of the metal, significantly reduces the cleaning threshold, so as to reduce the laser cleaning power and difficulty, and obtain good cleaning effect; therefore, the interaction of active agent, ultrasonic field, magnetic field and laser beam can effectively improve the cleaning efficiency and quality of the metal surface; it can be used for cleaning of low carbon steel, alloy steel, stainless steel, armor steel, bearing steel, die steel, aluminum alloy, titanium alloy, magnesium alloy, copper alloy, high temperature alloy, refractory metal and its surface attachments or oxides.

[0112] Example one

[0113] The cleaning object is the rust layer of ship steel plate AH36, which has the requirements of low cost, high efficiency, environmental protection, weldability and general precision. The active agent assisted external field combined laser cleaning process is as follows: the external field is a combined field of ultrasonic and magnetic field, the ultrasonic is a pre-applied coupling process, and the magnetic field is a simultaneously applied coupling process. The ultrasonic is located in the front space position of the laser beam, and the magnetic field is coaxial with the space position of the laser beam. The active agent assisted external field combined laser cleaning method uses continuous laser cleaning mode. The active agent composition is prepared by mixing 31% SiO2, 28.5% TiO2, 26% MnO2 and 14.5% graphene with a particle diameter of 30-45 μm, adding appropriate auxiliary reagents and mixing with distilled water. The active agent liquid is guided to the surface of the rust layer to form a liquid film through the catheter equipped with an ultrasonic wave generating device, and the active agent liquid is simultaneously ultrasonic cavitated and activated. The additional pulse alternating longitudinal magnetic field strength is 0.12 T, the magnetic field frequency is 0.8 KHz, the continuous laser cleaning power is 650 W, the continuous laser cleaning frequency is 256 Hz, the ultrasonic power is 650 W, and the ultrasonic frequency is 20 KHz. The cleaning efficiency is increased by more than 28%, the surface quality is increased by more than 24%, the cost is reduced by more than 10%, and the laser cleaning threshold is reduced by more than 20%. As shown in Figure 2 .

[0114] Example two

[0115] The cleaning object is the surface of nuclear stainless steel 00Cr19Ni10, and the cleaning area is medium, and the cleaning process has the requirements of high efficiency, environmental protection, weldability, high precision, high quality and no cost, and the active agent assisted external field composite laser cleaning process is that: the external field is a composite field of ultrasonic and magnetic field, the ultrasonic and magnetic field are coupled simultaneously, the ultrasonic is located in the front space position of the laser beam, the magnetic field is coaxial with the laser beam, and the active agent assisted external field composite laser cleaning method using pulsed laser cleaning mode; the active agent composition is prepared by mixing 22% Cr2O3, 15% SiO2, 21% TiO2, 13% Al2O3, 12% NaF, 7% Nd2O3 and 10% graphene with a particle diameter of 30-45 mu m, adding the corresponding auxiliary reagent, and coating the active agent on the surface of the nuclear stainless steel 00Cr19Ni10; 99.99% argon protection, argon flow is 16-22 L / min, external pulsed alternating longitudinal magnetic field strength is 0.15T, magnetic field frequency is 1.2KHz, pulsed laser cleaning power is 100W, pulsed laser repetition frequency is 80KHz, ultrasonic power is 820W, and ultrasonic frequency is 24Khz; the cleaning efficiency is increased by more than 18%, the surface performance is increased by more than 12%, and the laser cleaning threshold is reduced by more than 15%.

[0116] The active agent assisted external field composite laser cleaning sample of the application is compared with the ordinary laser cleaning sample as shown in the figure. Figures 4-6 The ultrasonic and magnetic field constitute the external field, the active agent, the external field and the cleaning laser beam plasma and material interact, can change the optical properties of the laser-induced plasma of solid and liquid materials, the active agent and the external field can change the condensation efficiency of the plasma after the laser-induced plasma expands, resulting in an increase in the aggregation density of the plasma, the active agent and the external field can change, affect and control the flow state of the charged fluid, the plasma shape, the metal ablation, the melting flow behavior and the element distribution, the external field and the thermal fluid, the electric fluid interact to produce various electromagnetic forces, have field-induced various effects, promote and improve the surface organization, the microstructure, the surface topography, the surface performance and the weldability of the cleaned metal, and the active agent and the external field can significantly increase the cleaning depth, reduce the cleaning threshold, improve the surface finish, reduce the reverse sinking of the ablation debris, and avoid the secondary pollution of the particles after cleaning and separation.

[0117] When the active agent particles are placed in the specified position of the surface to be cleaned by coating method, the solvent (acetone, ethanol and methanol) is used to dissolve it into paste, and then it is uniformly coated on the cleaning area to avoid blowing away. The active agent has high adhesion by using a solvent with high viscosity and an auxiliary adhesive, so that the active agent is uniformly covered on the surface of the object to be cleaned, the active agent is quickly dried by using the easily volatile solvent, and the solvent can also play a role in removing oil stains, has high steam pressure, and is beneficial to the cleaning behavior. The active agent can be prepared by adding auxiliary materials such as auxiliary agents, adhesives and solvents.

[0118] Finally, it is to be explained that the above embodiments are only used to illustrate the technical solutions of the present application but not to limit the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the purpose and scope of the present application, and all of them should be covered in the scope of the claims of the present application.

Claims

1. A surfactant-assisted external field composite laser cleaning method, characterized in that: The external field is an ultrasonic field, a magnetic field, or a composite field of ultrasonic and magnetic fields. The magnetic field is a longitudinal magnetic field or a transverse magnetic field, and the ultrasonic waves are longitudinal waves or transverse waves. The external field includes three working states or modes: pretreatment, cleaning, and posttreatment. The activator is a single substance or a mixture, and its active ingredient is selected from one or more of chlorides, oxides, fluorides, metallic elements, non-metallic elements, organic solvents, and distilled water. The laser cleaning can be either a dry laser cleaning method or a wet laser cleaning method; Includes the following steps: S1, Determine the surfactant components: The surfactant uses a characteristic variable function Фi to characterize the distribution coefficients of m components, where i is an integer from 1 to m, and m ≤ 30. The surfactant is composed of one or more components mixed together. Based on the material properties of the object to be cleaned and its comprehensive cleaning requirements, a reasonable surfactant composition is determined using material calculation methods, machine learning methods, or process experimentation. The surfactant powder diameter is 10–85 μm. S2, Determine the type of external field: using the characteristic variable function Γ j Three types of external fields are characterized, j being 1, 2, and 3. An ultrasonic transmitting device is set on the metal surface to be cleaned to form an ultrasonic field Γ1, or an excitation device is set to form a magnetic field Γ2, or an ultrasonic transmitting device and an excitation device are used together to form a composite field of sound and magnetic fields Γ3. The appropriate type of external field is determined according to the object to be cleaned and its comprehensive cleaning requirements. S3, Determine the laser cleaning method: using the characteristic variable function δ k Two types of laser cleaning are characterized, with k being 1 and 2. A suitable surfactant is applied or sprayed onto the surface of the metal object to be cleaned to form a dry laser cleaning method δ1, or a suitable surfactant is added to a liquid and sprayed or guided onto the surface of the metal object to be cleaned to form a liquid film to form a wet laser cleaning method δ2. The appropriate laser cleaning method is determined based on the object to be cleaned and its comprehensive cleaning requirements. S4, Determine the external field composite laser cleaning process: Adjust and optimize the external field process parameters and the laser cleaning process parameters, and organically couple them to form the optimal external field composite laser cleaning process parameters. The external field composite laser cleaning process parameters are reasonable process point values, linear intervals or regional ranges that are matched with each other by multiple parameters of the organic fusion of external field and laser. The external field process parameters include ultrasonic field process parameters, magnetic field process parameters, or composite field process parameters where ultrasonic field and magnetic field act simultaneously. The magnetic field process parameters include intermittent alternating magnetic field process parameters, pulsed alternating magnetic field process parameters, continuous alternating magnetic field process parameters, rotating magnetic field process parameters, or constant magnetic field process parameters. The laser cleaning process parameters include continuous laser cleaning process parameters, pulsed laser cleaning process parameters, or plasma laser shock wave cleaning process parameters. S5, Determine the spatiotemporal coupling process between the external field and the laser beam: using the characteristic variable function Ψ t Five types of time coupling processes between the external field and the laser beam are characterized, with t being 1, 2, 3, 4, and 5. Based on the object to be cleaned, the order of the external field and the laser beam applied to the object on the time coordinate axis is designed. Through comprehensive evaluation results, the relative time order of the coupling between the external field and the laser beam is determined to constitute the coupling process. The coupling process is either a coupling process Ψ1 in which the external field is applied to the cleaning laser beam in advance, or a coupling process Ψ2 applied simultaneously, or a coupling process Ψ3 applied subsequently, or a coupling process Ψ4 with delayed action, or a combination of the above two processes Ψ5, to ensure cleaning efficiency and cleaning quality. Based on the specific real-time location of the object to be cleaned and the direction of cleaning, and using the spatial physical reference coordinate system, the characteristic variable function β is adopted. s The three types of external field and laser beam spatial position coupling processes are characterized by s being 1, 2, and 3. The coupling process is either a pre-coupling process β1, a coaxial coupling process β2, or a post-coupling process β3 between the external field and the cleaning laser beam in space. S6. Determine the cleaning threshold and damage threshold, and optimize the surfactant-assisted external field composite laser cleaning process: Using surface morphology and microstructure detection technology, determine the cleaning standard of complete cleaning without damaging the substrate. Based on this, determine the minimum threshold and damage threshold for surfactant-assisted external field composite laser cleaning. Within the minimum threshold and damage threshold, optimize and improve the surfactant-assisted external field composite laser cleaning process and its parameters. Use the characteristic function f(x) to characterize the surfactant-assisted external field composite laser cleaning process, where x... Including characteristic variables Фi, Γ j δ k Ψ t β s All 5 characteristic variables have That is, f(x) is a combination of these 5 characteristic variables; S7, The object to be cleaned using the surfactant-assisted external field composite laser cleaning method: the most effective surfactant component Фi and the most suitable external field type Γ for surfactant-assisted external field composite laser cleaning. j The most appropriate laser cleaning method δ k Optimal coupling process Ψ t and β s The optimal process parameters f(x) are used to effectively clean the object to be cleaned. The organic integration of multiple factors constitutes an efficient, high-quality, precise, and economical surfactant-assisted external field composite laser cleaning method. The methods for determining the above-mentioned surfactant components, external field type, coupling process, and laser cleaning method are as follows: 1) When cleaning is difficult, requires high precision and high performance, covers a large area, has environmental protection requirements, has no cost requirements, and the material itself is difficult to clean, use a non-halogenated rare earth surfactant Ф. i +Combined field of acoustic field and magnetic field Γ3 method +Combined coupling process of early application and delayed continuation Ψ5 +Post-coupling process β3 +Active agent-assisted external field composite laser cleaning method of wet pulsed laser cleaning method δ2; 2) When precision and performance requirements are moderate, the cleaning area is medium, low cost is a requirement, and the material itself is not difficult to clean, use an surfactant with chloride or oxide components. i A surfactant-assisted external field composite laser cleaning method using ultrasonic field Γ1, simultaneous application of coupling process Ψ2, coaxial coupling process β2, and dry pulsed laser cleaning method δ1. 3) When precision and performance requirements are low, efficiency requirements are high, cleaning area is moderate, the material itself is of moderate cleaning difficulty, and cost requirements are moderate, an oxidizing or fluorinated surfactant Ф is used. i + Alternating magnetic field Γ2 method + Pre-applied coupling process Ψ1 + Coaxial coupling process β2 + Dry continuous laser cleaning method δ1 Active agent-assisted external field composite laser cleaning method; 4) When high performance, high efficiency, high quality, high precision are required, the cleaning area is large, the cost requirement is moderate, and the material cleaning difficulty is moderate, the active agent-assisted external field composite laser cleaning method is adopted, which is a rare earth-enhanced active agent Фi + a composite field of acoustic field and magnetic field Γ3 + a coupling process of delayed continued action Ψ4 + a post-coupling process β3 + a wet pulsed laser cleaning method δ2. 5) When the object to be cleaned is particulate matter or organic coating, and there are strict requirements for no substrate burn-off, high efficiency, high quality and high precision, the surfactant is added to the liquid. The dual mode of pretreatment and posttreatment using ultrasonic field and magnetic field is adopted to make the cavitation and activated surfactant water jet onto the surface to be cleaned. The surfactant-assisted external field composite laser cleaning method is adopted, which uses a composite field mode of ultrasonic field and intermittent alternating magnetic field coupling Γ3, wet plasma shock wave laser cleaning method. 6) When there are strict requirements for the stability of the cleaning process, the surface morphology after cleaning, the residual stress state, the corrosion resistance, the substrate burn-off, defects, efficiency, and weldability, an activator with a combination of rare earth or graphene-enhanced components is used. Ultrasonic fields and pulsed alternating magnetic fields, or ultrasonic fields and intermittent alternating magnetic fields, are simultaneously added to the entire cleaning process. The ultrasonic and magnetic fields adopt a dual working mode of pretreatment and posttreatment. The external field uses changeable and appropriate process parameters in pretreatment, cleaning, and posttreatment. 7) When dealing with particularly difficult-to-clean metal materials or particularly complex fine structures, the surfactant is added to the liquid to form a water jet onto the surface to be cleaned. The ultrasonic field and magnetic field are used simultaneously, applied in advance, and their effects are delayed. This allows the ultrasonic field to cavitate and activate the surfactant during the cleaning process. The parameters of the ultrasonic field and magnetic field applied in advance can be changed to adapt to the pretreatment needs. The external cleaning parameters are different from the external pretreatment parameters. Pulsed laser technology is used for cleaning. 8) When cleaning organic or inorganic objects in a low-temperature underwater environment, the surfactant is sprayed onto the surface of the object to be cleaned. A high-power ultrasonic field is used to preheat the local area to be cleaned, raising the temperature of the local underwater area to a suitable level for cleaning and ensuring that the surfactant is evenly distributed in the local area. Then, the ultrasonic field process parameters are adjusted to suit the underwater cleaning mode of ultrasonic-magnetic field coupled laser beam. A high-power continuous laser process is used for the entire cleaning process, forming a surfactant-assisted variable external field composite laser cleaning method.

2. The surfactant-assisted external field composite laser cleaning method according to claim 1, characterized in that: The machine learning method described herein is a machine learning-assisted method for determining reasonable surfactant components. It includes establishing a predictive model based on machine learning models for surfactant components, cleaning depth, surface roughness, and cleaning threshold in laser cleaning. By calculating and comparing the performance of multiple machine learning models, such as multilayer perceptron, random forest, K-nearest neighbor, or support vector machine, the most suitable predictive model for the effect of surfactant components is determined. The influence of surfactant components and external field composite laser cleaning process on the surface morphology, surface quality, surface properties, and surface structure of the object to be cleaned is analyzed. This provides the most suitable design scheme for effective surfactant component selection and the most scientific matching parameters for external field composite laser cleaning process for efficient, high-quality, precise, and low-cost laser cleaning. The dataset was established by considering various surfactant components for different processing applications and the material properties of the objects to be laser cleaned. These surfactants include elemental surfactants, halide surfactants, oxide surfactants, or composite surfactants. The main components of these surfactants contain one or more of the following substances: CaF2, MgF2, NaF, ALF3, MnCl2, CaCl2, MnCl2, CdCl2, ZnCl2, MgCl2, NiCl2, CaO, V2O5, SiO2, TiO2, MnO2, Al2O3, MgO, Cr2O3, B2O3, CuO, NiO, Ni, Al, Zn, Si, Te, Cr, Cd, Nb, V, graphene, and rare earth elements. Cleaning quality involves surface roughness, cleaning depth, and cleaning threshold. The model has 10 input layer variables and three output layer variables: surface roughness, cleaning depth, and cleaning threshold. The surface quality parameters of the cleaned surface were obtained through detection methods. The dataset was expanded by conducting experiments and collecting existing literature. Missing data was recorded as 0. After data normalization, an agent database of no less than 300 groups was established. Pearson coefficients were calculated and analyzed, and machine learning models of one of the following were established: multilayer perceptron, random forest, K-nearest neighbor, support vector machine, backpropagation neural network, and Bayesian ridge regression. The normalized dataset was divided into training and test sets. Early stopping was used to prevent overfitting. Calculate the root mean square error (RMSE), mean absolute percentage error (MAPE), and coefficient of determination (R²) for each model. 2 After training, the model is tested using a test set. The prediction results are normalized to convert them into a regular data format; By plotting scatter plots, the experimental values ​​and predicted values ​​of the test set are compared to evaluate the predictive ability of each model. Based on these indicators, the composition ratio parameters of the surfactant component that best predicts the quality of external field composite laser cleaning are determined.

3. The surfactant-assisted external field composite laser cleaning method according to claim 1, characterized in that: The cleaning target is the rust layer of marine steel plate AH36, which covers a very large area. Requirements include low cost, high efficiency, environmental friendliness, weldability, and general precision. The active agent-assisted external field composite laser cleaning process is as follows: the external field uses a composite field of simultaneous ultrasonic and magnetic fields. Ultrasonic fields are applied as a pre-existing coupling process, while magnetic fields are applied simultaneously. The ultrasonic field is located in front of the laser beam, and the magnetic field and laser beam are coaxial. This active agent-assisted external field composite laser cleaning method uses continuous laser cleaning. The activator is composed of 31% SiO2, 28.5% TiO2, 26% MnO2 with a particle diameter of 30-45 μm, and 14.5% graphene, which are ground and mixed. Appropriate auxiliary reagents are added and mixed with distilled water. The activator liquid is guided to the rust surface through a conduit equipped with an ultrasonic generator to form a liquid film. The activator liquid is simultaneously ultrasonically cavitated and activated. The applied pulsed alternating longitudinal magnetic field strength is 0.12T, the magnetic field frequency is 0.8KHz, the continuous laser cleaning power is 650W, the continuous laser cleaning frequency is 256Hz, the ultrasonic power is 650W, and the ultrasonic frequency is 20KHz.

4. The surfactant-assisted external field composite laser cleaning method according to claim 1, characterized in that: The cleaning target is the surface of nuclear-grade stainless steel 00Cr19Ni10. The area to be cleaned is moderate. There are requirements for high efficiency, environmental protection, weldability, high precision, and high quality. There are no cost requirements. The active agent-assisted external field composite laser cleaning process is as follows: the external field adopts a composite field in which ultrasound and magnetic field act simultaneously. The ultrasound and magnetic field are applied simultaneously in a coupled process. The ultrasound is located in front of the laser beam in the space. The magnetic field is coaxial with the laser beam. The active agent-assisted external field composite laser cleaning method uses pulsed laser cleaning mode. The activator is composed of 22% Cr2O3, 15% SiO2, 21% TiO2, 13% Al2O3, 12% NaF, 7% Nd2O3 with a particle diameter of 30-45 μm, and 10% graphene, which are ground and mixed together. Appropriate auxiliary reagents are added, and the activator is coated on the surface of nuclear stainless steel 00Cr19Ni10. 99.99% argon protection, argon flow rate 16-22 L / min, external pulsed alternating longitudinal magnetic field strength 0.15T, magnetic field frequency 1.2KHz, pulsed laser cleaning power 100W, pulsed laser repetition frequency 80KHz, ultrasonic power 820W, ultrasonic frequency 24KHz.

5. The surfactant-assisted external field composite laser cleaning method according to claim 1, characterized in that: The magnetic field is generated by a coil. The energized coil is an air coil, which is a spiral wound coil. The coil has an internal iron core and a cooling structure. The cooling structure ensures that the coil can work normally under high temperature conditions. The air coil is installed around the area of ​​the workpiece to be cleaned. The ultrasonic field is generated by an ultrasonic generator, which includes an ultrasonic generator, an ultrasonic vibrating head, and a clamping device. The ultrasonic vibrating head is integrated near the laser head and is at a certain distance from the area to be cleaned to prevent the laser beam from damaging the ultrasonic vibrating head. The excitation coil and the ultrasonic vibrating head form an integrated structured device of external field-workpiece-cleaner, thereby constructing an active agent-assisted external magnetic field composite laser cleaning method.

6. The surfactant-assisted external field composite laser cleaning method according to claim 1, characterized in that: The waveform, direction, frequency, and amplitude of the excitation current are adjustable or settable. The power, frequency, direction, waveform, and distance of the ultrasound are adjustable or settable. The magnetic field parameters and ultrasonic field parameters can be adjusted or set in the pre-treatment, cleaning, and post-treatment working states or modes to use suitable variable parameters and variable types for cleaning work.

7. The surfactant-assisted external field composite laser cleaning method according to claim 1, characterized in that: It can be used to clean the surface deposits or oxides of low carbon steel, stainless steel, armor steel, bearing steel, mold steel, aluminum alloy, titanium alloy, magnesium alloy, copper alloy, high temperature alloy, and refractory metals.

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