High-power rotating mirror laser cleaning process for rust removal

Abstract

The invention discloses a high-power rotating mirror laser cleaning process for derusting in the technical field of laser cleaning, which comprises the following steps: configuring a laser cleaning system which comprises a laser output unit with the output power not lower than 6kW and a rotating mirror scanning unit; the laser cleaning system is aligned with the rusted area on the surface of the carbon steel workpiece; identifying the corrosion grade of the corrosion area, and determining a corresponding target laser power density threshold value according to the identified corrosion grade; based on the target laser power density threshold value, setting laser power according to the diameter of a focusing light spot; according to the method, the advantages of high stability and large breadth of the high-power rotating mirror unit are combined with quantized process parameters, the problems that a traditional laser cleaning process depends on experience and is low in efficiency are solved, efficient, high-quality and repeatable cleaning of rust of the carbon steel component is achieved, and therefore the application range of the market is expanded.

Description

Technical Field

[0001] This invention relates to the technical field of laser cleaning, and in particular to a high-power rotating mirror laser cleaning process for rust removal. Background Technology

[0002] Laser cleaning technology, as a green and efficient non-contact surface treatment technology, has shown great potential in the field of industrial rust removal. Its basic principle is to use a high-energy-density laser beam to interact with contaminants on the substrate surface, thereby removing the contaminants through mechanisms such as vaporization, fragmentation, and thermal stress ablation.

[0003] In existing technologies, the mainstream solution for laser scanning is the galvanometer system. However, when faced with high-power continuous laser output (tens of watts or more) and ultra-large-format cleaning requirements, the galvanometer system reveals its inherent technical bottlenecks: insufficient power handling capacity due to overheating failure at the lens bonding joints, limited mechanical lifespan and stability, and a narrow effective processing area. Especially in the maintenance of large carbon steel components such as ships, bridges, and storage tanks, the areas to be treated are enormous, with varying degrees of rust, placing extremely high demands on cleaning efficiency, power, and adaptability. Existing galvanometer solutions are insufficient. Furthermore, current laser cleaning processes are generally based on experience and qualitative methods. Operators often rely on trial and error to adjust parameters, lacking quantitative process standards for different rust levels and optical systems.

[0004] Therefore, there is an urgent need in this field for a high-power laser cleaning method that can not only overcome hardware bottlenecks but also provide scientific and quantitative process parameters to achieve controllable, efficient, and large-area cleaning of carbon steel corrosion. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of the invention, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] Therefore, the purpose of this invention is to provide a high-power rotating mirror laser cleaning process for rust removal, in order to solve the problems of existing galvanometer laser cleaning systems being unable to withstand high-power continuous lasers and having narrow scanning areas. This invention combines the high stability and large-area advantages of high-power rotating mirror units with quantified process parameters, solving the problems of traditional laser cleaning processes relying on experience and having low efficiency. It achieves efficient, high-quality, and repeatable cleaning of rust on carbon steel components, thereby expanding the application scope of the market.

[0007] To solve the above-mentioned technical problems, the present invention provides a high-power rotating mirror laser cleaning process for rust removal, which adopts the following technical solution: including the following steps: configuring a laser cleaning system, the laser cleaning system including a laser output unit with an output power of not less than 6kW and a rotating mirror scanning unit; aligning the laser cleaning system with the rusted area on the surface of the carbon steel workpiece; identifying the rust level of the rusted area, and determining the corresponding target laser power density threshold according to the identified rust level; and setting the laser power based on the target laser power density threshold and the focused spot diameter.

[0008] Optionally, the corrosion level of the corroded area is classified into Class B, Class C, and Class D. When the corrosion level is Class B or Class C, the target laser power density threshold is set to be no less than 1×10⁻⁶. 6 W / cm 2 .

[0009] Optionally, when the corrosion level is Class D, the target laser power density threshold is set to be no less than 8.0 × 10⁻⁶. 6 W / cm 2 .

[0010] Optionally, the rotating mirror scanning unit includes a polyhedral rotating mirror and a focusing mirror. The polyhedral rotating mirror is an octahedral prism, and its reflective surface is coated with a high-reflectivity metal film.

[0011] Optionally, the effective cleaning linewidth W generated by the rotating mirror scanning unit is not less than 500 mm.

[0012] Optionally, the laser output unit is a continuous fiber laser with an output laser wavelength of 1060nm to 1080nm.

[0013] Optionally, the system further includes a method for establishing the laser power density threshold, the method comprising the following steps:

[0014] Through multiple laser cleaning experiments with different optical configurations, the laser power and the rotating mirror scanning speed were systematically varied.

[0015] Observe and record the removal effects of different parameter combinations on type B, C, and D rust on carbon steel surfaces;

[0016] Based on the removal effect, determine and calculate the laser power density corresponding to the critical states of "initial effective rust removal" and "complete rust removal";

[0017] Statistical analysis is performed on the critical power density to ultimately determine the power density threshold.

[0018] Optionally, the laser cleaning system includes a control unit, a laser output unit, and a rotating mirror scanning unit.

[0019] A laser output unit, connected to the control unit, is used to generate and output a continuous laser beam with a power of not less than 6 KW;

[0020] The rotating mirror scanning unit, connected to the control unit, includes a collimating mirror, a focusing mirror, a reflecting mirror, a rotating mirror, and a protective mirror, used to reflect and focus the continuous laser beam into a linear beam and project it onto the surface of the carbon steel workpiece.

[0021] The control unit is used to carry the laser output unit and the rotating mirror scanning unit, or to carry the carbon steel workpiece to be cleaned.

[0022] Optionally, the laser scanning speed can also be set by adjusting the rotation speed of the rotating mirror based on the target laser power density threshold.

[0023] Optionally, the configuration of the laser cleaning system includes parameters for configuring the laser cleaning system, including laser power P, fiber core diameter d, collimating focal length F1, focusing focal length F2, rotating mirror rotation speed N, and number of rotating mirror surfaces n;

[0024] The formula for calculating the diameter D of the focused spot is: D = d × F2 / F1; The formula for calculating the effective cleaning line width W is: W ≈ 2×F2×tan(2π / n); The formula for calculating the laser scanning speed V1 is: V1 = W × N × D; The formula for calculating the laser power density I is: I = P / [π × (D / 2)] 2 ].

[0025] In summary, the present invention has at least one of the following beneficial effects: This invention employs a rotating mirror scanning unit, fundamentally overcoming the bottleneck of traditional galvanometers where lenses and motors are prone to thermal failure under high-power, high-speed continuous lasers, achieving stable support for lasers with power of 6 kW and above. Through the cooperation of the rotating mirror and focusing lens, an ultra-large cleaning linewidth of over 500 mm is created, with a single cleaning area far exceeding that of traditional galvanometers, improving the overall cleaning efficiency of large workpieces. Through systematic experiments, a key power density threshold is provided for the rotating mirror cleaning process for the first time, transforming parameter setting from experience-based to scientifically quantified, ensuring the consistency and reliability of cleaning results. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the laser cleaning system of the present invention;

[0028] Figure 2 This is a schematic diagram of the rotating mirror scanning unit structure of the present invention;

[0029] Figure 3 This is a flowchart of the high-power rotating mirror laser cleaning process for rust removal according to the present invention;

[0030] Figure 4 This is a schematic diagram comparing the scanning linewidth of the rotating mirror of the present invention with that of the traditional galvanometer scanning mirror.

[0031] Explanation of reference numerals in the attached diagram: 1. Control unit; 2. Laser output unit; 3. Rotating mirror scanning unit; 301. Collimating mirror; 302. Focusing mirror; 303. Reflecting mirror; 304. Rotating mirror; 305. Protective mirror. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0033] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0034] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0035] Example 1

[0036] Reference Figures 1-3 This invention discloses a high-power rotating mirror laser cleaning process for rust removal, comprising the following steps:

[0037] A laser cleaning system is configured, which includes a laser output unit 2 with an output power of not less than 6kW and a rotating mirror scanning unit 3;

[0038] For the emerging high-power rotating mirror scanning unit 3, there is currently no publicly available, systematic research or process guidance on how much laser energy is needed to effectively and efficiently remove rust while ensuring the safety of the substrate. In particular, for the rotating mirror scanning unit 3, there is a lack of quantitative research and clear design guidelines on how the selection of its core parameters (such as the number of 304 facets of the rotating mirror) affects the scanning linewidth, energy utilization, and final cleaning effect.

[0039] The present invention configures a laser cleaning system including parameters for configuring the laser cleaning system. The parameters include the parameters of the laser output unit 2: laser power P, fiber core diameter d; and the parameters of the rotating mirror scanning unit 3: collimating focal length F1, focusing focal length F2, rotating mirror 304 rotation speed N, and rotating mirror 304 surface number n.

[0040] Based on the fiber core diameter d, collimating focal length F1, and focusing focal length F2, the focused spot diameter D is calculated. The formula for calculating the focused spot diameter D is as follows: D = d × F2 / F1; The formula for calculating the effective cleaning line width W is: W ≈ 2×F2×tan(2π / n); The effective cleaning linewidth W generated by the rotating mirror scanning unit 3 is not less than 500mm.

[0041] Based on the rotational speed N and focused spot diameter D of the rotating mirror 304, and the effective cleaning linewidth W formed by the rotating mirror scanning unit 3 on the workpiece surface, the laser scanning speed V1 is calculated. The formula for calculating the laser scanning speed V1 is: V1 = W × N × D; Based on the laser power P and the focused spot diameter D, the laser power density I acting on the workpiece surface is calculated; the formula for calculating the laser power density I is: I = P / [π × (D / 2)] 2 ].

[0042] The rust levels of the rusted areas are classified into categories B, C, and D. The laser cleaning system is then aimed at the rusted areas on the surface of the carbon steel workpiece. When the rust level is category B or C, the target laser power density threshold is set to be no less than 1 × 10⁻⁶. 6 W / cm 2 When the corrosion level is Class D, the target laser power density threshold is set to be no less than 8.0 × 10⁻⁶. 6 W / cm 2 Based on the corrosion level, the laser power P and the laser scanning speed V1 are adjusted to control the laser power density I to be no lower than a preset power density threshold, while clarifying the relationship between the laser scanning speed and the rotation speed of the rotating mirror 304.

[0043] Based on the target laser power density threshold, the laser power is set according to the focused spot diameter. It also includes setting the rotational speed of the rotating mirror 304 based on the target laser power density threshold to set the laser scanning speed.

[0044] In detail, in this embodiment, the rotating mirror scanning unit 3 includes a polyhedral rotating mirror 304 and a focusing mirror 302. The number of faces of the polyhedral rotating mirror 304 in the rotating mirror scanning unit 3 is selected based on a systematic balance of scanning efficiency (linewidth), energy utilization rate, and cleaning capability (power density). The scanning linewidth is related to the number of faces of the rotating mirror 304 and the focal length of the focusing mirror 302, while the effective energy utilization rate of the system depends on the coverage of the laser beam on the reflective surface of the rotating mirror 304. In the pre-focusing structure of the present invention, the laser is projected onto the surface of the rotating mirror 304 after collimation and focusing. If the beam size exceeds the effective receiving range of a single reflective surface, some laser energy will be lost. Through systematic optical simulation and experimental verification, the eight-faceted rotating mirror 304, under a typical focal length configuration, can achieve a scanning linewidth of not less than 500 mm while ensuring that the laser beam is completely received by the reflective surface, with an energy utilization rate of over 60%, thereby ensuring that the laser power density acting on the workpiece surface is not lower than the rust removal threshold established by the present invention.

[0045] like Figure 2 As shown, after the laser beam is focused, it is reflected by the high-speed rotating mirror 304, forming a continuous linear spot on the working surface. The scanning linewidth is determined by the number of faces of the rotating mirror 304, the focal length of the focusing mirror 302, and the laser incident angle.

[0046] Determining the number of faces of the rotating mirror 304: The number of faces (n) of the rotating mirror 304 is a key parameter determining the scanning linewidth (W) and the system rotation speed requirements. The scanning linewidth can be approximately calculated using the formula W ≈ 2 × F² × tan(2π / n). To achieve the goal of an effective cleaning linewidth of not less than 500 mm set by this invention, the performance of rotating mirrors 304 with different numbers of faces at typical focal lengths was analyzed. The results show that: while a four-face rotating mirror 304 can achieve a very large linewidth, it requires extremely high rotation speeds to achieve an effective scanning overlap rate, posing a severe challenge to mechanical stability; rotating mirrors 304 with twelve or more faces require the use of long focal length focusing lenses 302 to maintain the linewidth, which will lead to an increase in the spot diameter, resulting in a significant decrease in power density and making it difficult to meet the cleaning threshold for Class D corrosion. An eight-face rotating mirror 304 can achieve a scanning linewidth of over 500 mm within a focal length range of 500-600 mm, and the required rotation speed (e.g., 800-1000 r / min) is within a mechanically reliable and efficient range.

[0047] Energy utilization efficiency analysis and determination of the number of surfaces of rotating mirror 304: In the front focusing optical structure of this invention, the laser output from the QBH connector, after passing through collimating lens 301 and focusing lens 302, forms a light spot of a certain size when it reaches the reflecting surface of rotating mirror 304. The diameter of this light spot must match the size of the reflecting surface of rotating mirror 304 to ensure efficient energy utilization. The formula for calculating energy utilization efficiency (η) is: η = L−(d / sin(α)) / L×100%

[0048] Where L is the width of the reflecting surface of the rotating mirror 304, d is the spot diameter reaching the rotating mirror 304, and α is the laser incident angle. Through calculations on various configurations, under the optimal configuration (F60 collimation, F600 focusing, 75 μm core diameter), the spot diameter d reaching the rotating mirror 304 is calculated to be approximately 6.9 mm. Assuming the width of the rotating mirror 304 L = 25 mm and the incident angle α = 45°, the energy utilization rate η ≈ 61%. This configuration, while ensuring high energy utilization, achieves an effective scanning linewidth of approximately 500 mm and a laser intensity of 1.36 × 10⁻⁶ mm. 6 With a power density of W / cm², it fully meets the cleaning requirements for Class B / C corrosion. Therefore, the polyhedral rotating mirror 304 is an octahedral prism, and a high-reflectivity metal film is coated on its reflective surface.

[0049] A comparative analysis of various optical configurations was conducted, with core evaluation indicators including: theoretical spot diameter, system energy efficiency, maximum achievable power density, and effective cleaning linewidth. The key selection analysis results are summarized in the table below:

[0050] Based on the above analysis, the preferred configuration is determined to be: an octagonal rotating mirror 304, an F60 collimating mirror 301, and an F600 front focusing mirror 302, coupled with a 6 kW continuous fiber laser with a 75 μm core diameter. This configuration ensures a power density of 1.36 × 10⁻⁶ kWh. 6 While significantly exceeding the cleaning threshold (I3) for B / C type rust (W / cm2), it maintains a reasonable working distance of approximately 400 mm and a good energy utilization rate of 61%, and can achieve an effective cleaning linewidth of over 500 mm.

[0051] The laser output unit 2 is a continuous fiber laser with an output laser wavelength of 1060nm to 1080nm.

[0052] Example 2

[0053] Based on the same concept as in Embodiment 1 above, this high-power rotating mirror laser cleaning process for rust removal further includes a method for establishing the laser power density threshold, the method for establishing the laser power density threshold comprising the following steps:

[0054] S1. Experimental Design and Preparation: To obtain universally applicable conclusions, this experiment employed multiple different optical configurations to cover a wide range of operating conditions. The main experimental equipment and configurations are shown in the table below:

[0055] The test samples were carbon steel plates with naturally formed B, C, and D type rust. In each configuration, the laser power P was systematically adjusted, and a suitable rotating mirror rotation speed of 304 was selected according to the laser scanning speed V1 calculation formula, thus changing the laser scanning speed V1.

[0056] S2. Experimental Procedure and Critical State Determination: For each optical configuration and scanning speed combination, starting from the highest power, the laser power was gradually reduced in 200 W increments. The removal effect on type B, C, and D rust on carbon steel surfaces under different parameter combinations was observed and recorded in real time. We clearly defined two critical states:

[0057] "Initial effective rust removal" state (corresponding to threshold I1): After laser spot scanning, the surface rust (B / C type) is barely removed, or the C type rust is completely removed and the D type rust begins to be removed.

[0058] "Completely Remove Rust" status (corresponding to thresholds I2 / I3): For B / C type rust, the surface is cleaned until it reveals the original metallic color (bright white state); for D type rust, the rust layer is completely removed (although the underlying oxide scale may still be present).

[0059] S3 Data Analysis and Threshold Determination: Record the laser power P and the measured spot diameter D' when the above critical state is reached, and use the formula I = P / [π×(D′ / 2)] to determine the threshold. 2 Calculate the critical power density.

[0060] A comprehensive analysis of the data from all test sequences revealed a key pattern: despite significant differences in optical configuration (spot size) and scanning speed (dwell time), the critical power density required to achieve a specific cleaning effect converged within a relatively stable range. For example, with a spot diameter of 0.71 mm, the power density for "initial effective rust removal" was approximately 0.30-0.40 × 10⁻⁶. 6 W / cm 2 Between; and with a spot diameter of 0.16 mm, the power density required to "completely remove Class D corrosion" is approximately 9.95-11.96 × 10⁻⁶. 6 W / cm 2 between.

[0061] Through statistical analysis of a large amount of critical data, we finally established the following power density thresholds to guide the process:

[0062] The power density threshold I1 for initial effective rust removal is ≥ 0.4 × 10⁻⁶. 6 W / cm 2 .

[0063] The power density threshold I3 required for thorough cleaning of Class B / C rust is ≥ 1.0 × 10⁻⁶. 6 W / cm 2 .

[0064] The power density threshold I² for completely removing Class D corrosion is ≥ 8.0 × 10⁻⁶. 6 W / cm 2 .

[0065] Example 3

[0066] Based on the same concept as in Embodiment 1 above, the laser cleaning system for a high-power rotating mirror laser cleaning process for rust removal includes a control unit 1, a laser output unit 2, and a rotating mirror scanning unit 3.

[0067] Laser output unit 2, connected to the control unit 1, is used to generate and output a continuous laser beam with a power of not less than 6 KW;

[0068] The rotating mirror scanning unit 3, connected to the control unit 1, includes a collimating mirror 301, a focusing mirror 302, a reflecting mirror 303, a rotating mirror 304, and a protective mirror 305, used to reflect and focus the continuous laser beam into a linear beam and project it onto the surface of the carbon steel workpiece.

[0069] Control unit 1 is used to carry the laser output unit 2 and the rotating mirror scanning unit 3, or to carry the carbon steel workpiece to be cleaned.

[0070] The rotating mirror scanning unit 3 is the core of this invention. It includes a collimating mirror 301 to convert the initially diverging laser light into parallel light; a focusing mirror 302 to focus the laser light, concentrating the energy; a reflecting mirror 303 to change the path of the light; an octagonal rotating mirror 304 to convert the laser light from a point to a line; and a protective mirror 305 to prevent external dust and dirt from contaminating the internal mirrors. This structure forms a complete optical path system that ensures effective surface cleaning with the laser in a long linewidth configuration, and also allows for a larger effective range of the laser light on the rotating mirror 304 surface through pre-focusing, thereby improving energy utilization.

[0071] Example 4: Implementation of cleaning process based on quantization threshold and optimal configuration:

[0072] Reference Figures 1-4 This embodiment demonstrates how to apply the results of the foregoing embodiments to perform efficient and high-quality cleaning of B / C type rust on a large carbon steel component.

[0073] S1. System Configuration:

[0074] The preferred configuration determined in Embodiment 1 is adopted. The control unit 1 is preset with the power density threshold established in Embodiment 1.

[0075] S2. Process parameter settings:

[0076] like Figure 3 As shown in the process flow diagram, after the operator identifies the workpiece surface rust level as B / C, they adjust the parameters to the threshold I3 ≥ 1.0×10 6 W / cm 2 .

[0077] Given that the theoretical spot diameter D = 0.75 mm, and based on the working distance and the scanning angle of the rotating mirror 304, the scanning line width W > 500 mm.

[0078] To balance cleaning effectiveness and efficiency, the rotation speed of the rotating mirror 304 was set to N = 800 r / min, at which point the scanning speed was 53.33 m / s. At this speed, the cleaning travel speed was set to v = 15 mm / s.

[0079] The system calculates and sets the laser power to P = 6000 W (full power). At this point, the actual power density I = 1.36 × 10⁻⁶ W. 6 W / cm 2 > I3, ensuring sufficient cleaning capability.

[0080] S3. Perform cleaning and observe the results:

[0081] The system was started, and the cleaning head moved at a speed of 15 mm / s. The rotating mirror 304 generated an ultra-wide scanning line spot at a speed of 800 r / min, performing a one-time comprehensive cleaning of the component surface. As a result, B / C type rust was removed in one go, uniformly and thoroughly, revealing the metal substrate without damage.

[0082] Comparative Example: Compared with Traditional Galvanometer Cleaning Solutions

[0083] like Figure 4 As shown in the comparative diagram, to highlight the technological advancements of this invention, a mainstream high-power galvanometer cleaning device was used for comparison. This galvanometer system was configured with: a 3 KW laser, a 50 μm core diameter, F50 collimation, F400 focusing, and a measured spot diameter of approximately 0.34 mm.

[0084] To achieve a similar level of cleanliness in cleaning B / C type rust, the galvanometer system power should be set to 1250 W and the scanning speed to 53.33 m / s. At this setting, the power density is approximately 1.38 × 10⁻⁶. 6 W / cm 2 However, limited by the deflection angle of the galvanometer and the window size of the field lens, its maximum effective cleaning linewidth is only about 120 mm. Figure 4 As shown on the left.

[0085] At the same cleaning travel speed of 15 mm / s, when processing workpieces of the same area, the rotating mirror 304 system of this invention ( Figure 4 The time required (on the right) is only about 1 / 4 of that of a traditional galvanometer system, with an efficiency improvement of over 300%. Furthermore, under prolonged high-speed, high-power operation, the internal cemented mirrors of a galvanometer system are at risk of failure due to thermal effects, and the motor also faces the risk of runaway. The rotating mirror 304 system of this invention, due to its robust mechanical structure and heat-resistant design, exhibits superior long-term operational stability.

[0086] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A high power rotating mirror laser cleaning process for rust removal, characterized by: Includes the following steps: Configure a laser cleaning system, the laser cleaning system including a laser output unit (2) with an output power of not less than 6kW and a rotating mirror scanning unit (3). The laser cleaning system is aimed at the rusted area on the surface of the carbon steel workpiece; Identify the corrosion level of the corroded area, and determine the corresponding target laser power density threshold based on the identified corrosion level; Based on the target laser power density threshold, the laser power is set according to the focused spot diameter.

2. A high power rotating mirror laser cleaning process for rust removal as claimed in claim 1 wherein: The corrosion levels of the corroded areas are classified into categories B, C, and D. When the corrosion level is category B or C, the target laser power density threshold is set to be no less than 1 × 10⁻⁶. 6 W / cm 2 .

3. A high power rotating mirror laser cleaning process for rust removal as claimed in claim 2 wherein: When the corrosion level is Class D, the target laser power density threshold is set to be no less than 8.0 × 10⁻⁶. 6 W / cm 2 .

4. A high power rotating mirror laser cleaning process for rust removal as claimed in claim 1 wherein: The rotating mirror scanning unit (3) includes a polyhedral rotating mirror (304) and a focusing mirror (302). The polyhedral rotating mirror (304) is an octagonal prism, and its reflective surface is coated with a high-reflectivity metal film.

5. A high power rotating mirror laser cleaning process for rust removal as claimed in claim 1 wherein: The effective cleaning linewidth W generated by the rotating mirror scanning unit (3) is not less than 500 mm.

6. A high power rotating mirror laser cleaning process for rust removal according to any one of claims 1-5, characterized in that: The laser output unit (2) is a continuous fiber laser with an output laser wavelength of 1060nm to 1080nm.

7. A high power rotating mirror laser cleaning process for rust removal as claimed in claim 3 wherein: It also includes a method for determining the laser power density threshold, the method comprising the following steps: Through multiple laser cleaning experiments with different optical configurations, the laser power and the scanning speed of the rotating mirror (304) were systematically changed; Observe and record the removal effects of different parameter combinations on type B, C, and D rust on carbon steel surfaces; Based on the removal effect, determine and calculate the laser power density corresponding to the critical states of "initial effective rust removal" and "complete rust removal"; Statistical analysis is performed on the critical power density to ultimately determine the power density threshold.

8. The high-power rotating mirror laser cleaning process for rust removal according to claim 5, characterized in that: The laser cleaning system includes a control unit (1), a laser output unit (2), and a rotating mirror scanning unit (3). The laser output unit (2) is connected to the control unit (1) and is used to generate and output a continuous laser beam with a power of not less than 6 KW. The rotating mirror scanning unit (3), connected to the control unit (1), includes a collimating mirror (301), a focusing mirror (302), a reflecting mirror (303), a rotating mirror (304), and a protective mirror (305), used to reflect and focus the continuous laser beam into a linear beam and project it onto the surface of the carbon steel workpiece; The control unit (1) is used to carry the laser output unit (2) and the rotating mirror scanning unit (3), or to carry the carbon steel workpiece to be cleaned.

9. A high power rotating mirror laser cleaning process for rust removal as claimed in claim 8 wherein: It also includes setting the rotation speed of the rotating mirror (304) based on the target laser power density threshold to set the laser scanning speed.

10. A high power rotating mirror laser cleaning process for rust removal as claimed in claim 9 wherein: The configuration of the laser cleaning system includes parameters for configuring the laser cleaning system, including laser power P, fiber core diameter d, collimation focal length F1, focusing focal length F2, rotational speed N of the rotating mirror (304), and number of surfaces n of the rotating mirror (304). The formula for calculating the diameter D of the focused spot is: D = d × F2 / F1; The formula for calculating the effective cleaning line width W is: W ≈ 2×F2×tan(2π / n); The formula for calculating the laser scanning speed V1 is: V1 = W × N × D; The formula for calculating the laser power density I is: I = P / [π x (D / 2) 2 ].

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