A laser scratching process applied to a metal surface

Abstract

The application relates to the technical field of metal surface treatment, in particular to a laser scraping process applied to a metal surface, the scraping process is that a laser head of a laser system emits a laser beam to act on a metal surface to be treated, and is used for simultaneously performing cleaning and roughening operations on the metal surface; a laser device for realizing the process is simple in structure, can be designed to be small-sized, and is better in applicability, in particular in complex application scenes such as bridge steel structures, the advantages of the laser scraping process are more obvious; before metal welding, the laser scraping process can realize welding after cleaning, and greatly improves construction efficiency, in particular in bridge welding operations requiring rapid response and high precision; before metal painting, the laser scraping process can not only completely remove a surface anticorrosive paint and a rust layer, but also can form uniform roughness on the surface, and provides an ideal base material strip for painting.

Description

Technical Field

[0001] This application belongs to the field of metal surface treatment technology, and in particular relates to a laser scraping process applied to metal surfaces. Background Technology

[0002] Metal surfaces typically require pre-treatment before painting or welding to ensure the quality of the painting or welding. For example, steel components in infrastructure may have rust. Traditional rust removal methods mostly use physical or chemical methods. After cleaning, roughening treatment is required to enhance the adhesion of the paint, such as the commonly used sandblasting roughening process. Traditional processes are not only inefficient, but also easily damage the metal surface and pollute the environment.

[0003] Chinese patent 201910277672.X discloses a laser cleaning-texturing composite processing method. This method splits the laser emitted by a laser into two beams: one for laser cleaning and the other for laser texturing, thus achieving a composite laser cleaning-texturing process on the material. Alternatively, two lasers can be used to generate two laser beams, which are applied to the workpiece surface one after the other, with the cleaning laser preceding the texturing laser, thereby achieving a composite laser cleaning-texturing process on the material. While this invention patent (201910277672.X) offers improved efficiency compared to traditional processes, it essentially still involves combining two processes (laser cleaning and texturing) separately to achieve the cleaning and texturing effect. The device used to implement this process has a complex structure, large size, and is easily limited by space and environment, resulting in high manufacturing and operating costs. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a laser scraping process for metal surfaces to overcome the shortcomings of the prior art. The process involves using a laser beam to act on the metal surface to be treated, thereby simultaneously cleaning and texturing the metal surface, aiming to solve at least one of the above-mentioned technical problems.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A laser scraping process for metal surfaces, wherein the scraping process uses a laser beam emitted from the laser head of a laser system to act on the metal surface to be treated, for simultaneous cleaning and texturing of the metal surface;

[0007] The laser system includes an optical path system for guiding and shaping the laser beam and causing the modulated laser beam to act on the surface of the metal material.

[0008] The power density of the laser beam modulated by the optical path system is 50-200 MW / cm². 2 The laser beam has a spot size of 50-200 μm;

[0009] The laser system also includes a feedback system, which is used to collect workpiece surface temperature information, laser beam angle and position information, and feed the collected information back to the laser system's processing unit to adjust the laser head's emission power, angle and position.

[0010] Preferably, in a laser scratching process for metal surfaces according to the present invention, the optical path system includes a collimating mirror, a first galvanometer, a second galvanometer, and a lens group.

[0011] Preferably, in a laser scratching process for metal surfaces according to the present invention, the feedback system includes a temperature management unit, which includes a temperature sensor for detecting the surface temperature information of the metal workpiece.

[0012] Preferably, in a laser scratching process for metal surfaces according to the present invention, the feedback system further includes a gyroscope mounted on the laser head for detecting the laser beam angle and position information.

[0013] Preferably, the present invention provides a laser scraping process for metal surfaces, wherein the laser scraping process further treats waste materials through a protective system. The protective system includes a protective cover, an air blowing device, and a dust suction device. The protective cover is used to enclose the working space, the air blowing device is used to blow away the stripped material from the workpiece surface, and the dust suction device is used to absorb the stripped material and waste gas inside the protective cover.

[0014] Preferably, in a laser scraping process for metal surfaces according to the present invention, before the laser scraping operation, the substrate to be retained and the dirt and coating to be removed are determined according to the material characteristics, shape and size, surface quality and painting requirements of the steel structure workpiece to be scraped, and the process parameters are determined according to the equipment and the properties of the laser beam.

[0015] Preferably, the laser scratching process of the present invention applied to metal surfaces includes the following steps in selecting the parameters of the laser scratching process:

[0016] a) Determine the energy density threshold range by scratching the material properties;

[0017] b) By conducting a scratching experiment, the energy density parameter was adjusted, and the damage threshold was determined.

[0018] c) Identify the relationship between the damage threshold and surface morphology characteristics and properties;

[0019] When the energy density exceeds the damage threshold corresponding to the desired morphological characteristics, the energy density boundary of laser scraping is determined;

[0020] d) Based on the results of the scratching experiment, select and optimize the process parameters of laser wavelength, power density, laser duty cycle, scratching efficiency, and spot diameter. The formula for calculating laser power density is: Pd=P / S.

[0021] Where: Pd—laser power density, unit MW / cm² 2 ;

[0022] P—Average laser power, in MW;

[0023] S—Spot area, in cm² 2 .

[0024] Preferably, in the laser scraping process for metal surfaces according to the present invention, the process parameters during the scraping operation further include: a laser wavelength of 1.0-1.1 μm and a processing speed of 3-14 m / s. 2 / h.

[0025] Preferably, in the laser scratching process of the present invention applied to metal surfaces, the workpiece needs to be protected during and after the scratching operation. After the scratching operation, the workpiece also needs to be inspected, and the inspection items include workpiece appearance, surface roughness, coating adhesion and surface hardness.

[0026] Preferably, the present invention provides a laser scraping process for metal surfaces, wherein the metal to be treated includes steel and its alloys, aluminum and its alloys, and titanium and its alloys.

[0027] The beneficial effects of this invention are:

[0028] (1) The laser scraping process of the present invention uses a laser beam to act on the metal surface to be treated, so as to simultaneously clean and roughen the metal surface. The laser device that realizes this process has a simple structure and can be miniaturized, making it more applicable. Especially in complex application scenarios such as bridge steel structures, the advantages of the laser scraping process of the present invention are more obvious.

[0029] (2) Before metal welding, this laser scraping process can be used to achieve cleaning and welding at the same time, which greatly improves the construction efficiency, especially in bridge welding operations that require rapid response and high precision.

[0030] (3) Before painting the metal, using this laser scraping process can not only completely remove the anti-corrosion paint and rust layer on the surface, but also form a uniform roughness on the surface, providing ideal substrate conditions for coating. Compared with traditional grinding or chemical cleaning methods, this laser scraping has the advantages of high efficiency and no pollution, and is more in line with modern environmental protection requirements.

[0031] (4) This laser scraping process technology is pollution-free and can be precisely controlled, meeting the development requirements of the cleaning operation field for more refined and green development. Attached Figure Description

[0032] The technical solution of this application will be further described below with reference to the accompanying drawings and embodiments.

[0033] Figure 1 This is a schematic diagram of the process flow of an embodiment of this application;

[0034] Figure 2 This is a schematic diagram of the laser system structure according to an embodiment of this application;

[0035] Figure 3 This is a schematic diagram of the structure of the laser head according to an embodiment of this application;

[0036] Figure 4 These are comparative images of the appearance of ordinary steel after multiple laser scratching experiments according to embodiments of this application;

[0037] Figure 5 These are enlarged views of the surface and cross-section of ordinary steel before and after laser scratching, according to embodiments of this application.

[0038] The attached figures are labeled as follows:

[0039] Collimating lens 11, first galvanometer 12, second galvanometer 13 and lens group 14, laser head 21, protective cover 22, air blower 23, dust suction tube 24, laser beam 25. Detailed Implementation

[0040] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0041] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and 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, and therefore should not be construed as limiting the scope of protection of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0042] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0043] The technical solution of this application will now be described in detail with reference to the accompanying drawings and embodiments.

[0044] Example: This example provides a laser scratching process applied to metal surfaces, referring to... Figure 2 and Figure 3 In this embodiment, the scraping process uses a laser beam 25 emitted from the laser head 21 of the laser system to act on the metal surface to be treated, simultaneously performing cleaning and roughening operations on the metal surface. The metal to be treated includes steel and its alloys, aluminum and its alloys, and titanium and its alloys. In this embodiment, the metal to be treated is ordinary steel plate (Q370qe steel plate).

[0045] Reference Figure 2 The laser system includes a laser for emitting laser light, an optical path system (scanning actuator), a control system, and a cooling device.

[0046] The optical path system is used to guide and shape the laser beam and ensure that the modulated laser beam acts on the surface of the metallic material. Specifically, refer to... Figure 3 The optical path system includes a collimating mirror 11, a first galvanometer 12, a second galvanometer 13, and a lens group 14, wherein the lens group 14 includes at least one convex lens. In this embodiment, the lens group 14 includes five lenses arranged in parallel.

[0047] The laser emitted by the laser passes through the collimating lens 11, is reflected by the first galvanometer 12 onto the second galvanometer 13, is reflected by the second galvanometer 13 onto the first convex lens, is initially focused by the first convex lens and then projected onto the second convex lens, where it is refocused and reduced in size before being applied to the surface of the metal material to be treated as a laser scraping beam.

[0048] Preferably, one laser scratching process applied to a metal surface in this embodiment refers to... Figure 1 Before laser scraping, based on the material characteristics, shape and size, surface quality and painting requirements of the steel structure workpiece to be scraped, it is necessary to determine the substrate to be retained and the dirt and coating to be removed, and to determine the process parameters according to the equipment and the properties of the laser beam.

[0049] Preferably, in this embodiment, a laser scratching process applied to a metal surface includes the following steps for selecting the parameters of the laser scratching process:

[0050] a) Determine the energy density threshold range by scratching the material properties;

[0051] b) By conducting a scratching experiment, the energy density parameter was adjusted, and the damage threshold was determined.

[0052] c) Identify the relationship between the damage threshold and surface morphology characteristics and properties;

[0053] When the energy density exceeds the damage threshold corresponding to the desired morphological characteristics, the energy density boundary of laser scraping is determined;

[0054] d) Based on the results of the scratching experiment, select and optimize the process parameters of laser wavelength, power density, laser duty cycle, scratching efficiency, and spot diameter. The formula for calculating laser power density is: Pd=P / S.

[0055] Where: Pd—laser power density, unit MW / cm² 2 ;

[0056] P—Average laser power, in MW;

[0057] S—Spot area, in cm² 2 .

[0058] In the embodiments, multiple sets of experimental tests were conducted to select the laser scratching process parameters for ordinary steel surfaces, referring to... Figure 4 The experimental process and results are as follows:

[0059] Experimental Group 1: The laser wavelength in the process parameters is 1.0-1.1μm, the duty cycle is 80-100%, and the processing speed is 10-14m / s. 2 The power density of the laser beam modulated by the optical path system is 0.6-25 MW / cm² / h. 2 The laser beam spot size is 50-200um. At this time, the rust removal effect on the steel surface is completed. After laser surface scraping, it can be observed with the naked eye or a magnifying glass that there is no residue of the substances to be removed (metal oxides, plating layers, coatings, contaminants, etc.) on the workpiece surface after laser scraping. However, the roughening effect is not obvious. The surface roughness is measured with a probe-type profile measuring instrument or a three-dimensional optical profile measuring instrument. The roughness after roughening is approximately equal to 0. The adhesion of the re-prepared coating after laser scraping is tested. The adhesion between the substrate surface after laser scraping and the re-prepared coating is equal to or approximately equal to the adhesion before the coating was removed. That is, the increased adhesion is approximately equal to 0MPa.

[0060] Experimental Group 2: Laser wavelength 1.0-1.1μm, duty cycle 50-80%, processing speed 5-10m / s. 2 / h, the power density of the laser beam modulated by the optical path system is 25-60MW / cm. 2 The laser beam spot size is 50-200um. At this time, according to the test method of Experiment Group 1, the rust cleaning effect on the surface of ordinary steel is visually completed, the roughening effect is obvious, the surface roughness of the roughened steel is 20-50μm, and the adhesion test is greater than 3MPa.

[0061] Experimental Group 3: Laser wavelength 1.0-1.1μm, duty cycle 10-50%, processing speed 3-8m / s. 2 / h, the power density of the laser beam modulated by the optical path system is 50-76MW / cm. 2 The laser beam spot size is 50-200um. Following the same testing method as experimental groups one and two, the rust removal effect on the surface of ordinary steel is visually complete, and the roughening effect is very obvious. The surface roughness of the roughened steel is 50-100μm, and the adhesion test is greater than 5.9MPa.

[0062] The laser system in this embodiment also includes a feedback system, which is used to collect workpiece surface temperature information, laser beam angle and position information, and feed the collected information back to the processing unit of the laser system to adjust the emission power, angle and position of the laser head.

[0063] Specifically, the feedback system includes a temperature management unit, which includes a temperature sensor to detect the surface temperature of the metal workpiece. Based on the properties of the material, a temperature range is set. When the surface temperature of the metal workpiece exceeds the upper limit of the temperature range, the processing unit of the laser system will reduce the power of the laser beam or increase the duty cycle during laser scraping, thereby reducing the surface temperature of the metal workpiece and preventing damage to the workpiece.

[0064] Preferably, in this embodiment of a laser scraping process applied to metal surfaces, the feedback system further includes a gyroscope mounted on the laser head for detecting the laser beam angle and position information. Based on the shape characteristics of the material and the working space, a range of laser beam rotation angles is set. When the laser beam deflection angle exceeds the set range, the processing unit of the laser system will correct the rotation angle of the laser beam to ensure the work quality and safety of laser scraping.

[0065] Preferably, in this embodiment of a laser scraping process applied to a metal surface, the laser system further includes a protective system, which includes a protective cover 22, an air blowing device, and a dust collection device. In this embodiment, the protective cover 22 is configured as a shell structure with a hollow bottom. During operation, it covers the surface of the workpiece to enclose the working space. The laser head is located on the top of the protective cover 22. The air blowing device is configured as an air blowing knife 23. The air blowing knife 23 blows out a high-speed airflow, oxygen flow, or nitrogen flow to scrape the metal surface, promptly blowing away the stripped material from the working surface after the laser scraping operation, thereby improving the scraping effect. The dust collection device uses a vacuum cleaner connected to the protective cover 22 through a dust suction pipe 24, and the dust suction pipe opening is set opposite to the air blowing knife 23 to improve the discharge speed of stripped material and exhaust gas.

[0066] This embodiment describes a laser scraping process applied to metal surfaces, referring to... Figure 1 and Figure 5 The specific steps are as follows:

[0067] Start the equipment and check that the laser head, motion mechanism, and laser operation are normal. Use the red light indicator to adjust and determine the surface treatment position. Wear laser safety goggles and ensure that there are no personnel, equipment, or other hazardous materials in the laser transmission path. Conduct a comprehensive inspection of the workpiece to be treated, confirming its surface condition, material type, and structural integrity to ensure it is suitable for laser scratching.

[0068] Before the laser scraping work is carried out, the process specification documents are followed. Based on the different surface roughness requirements of steel beams, supports and auxiliary steel structures before coating, and combined with the existing experimental data of steel substrates, the range of laser scraping process parameters is determined using Appendix Table 1. After verification, the laser scraping process parameters are determined.

[0069]

[0070] The following processing requirements must be followed during laser scratching operations:

[0071] The principle of processing should be followed from the near end to the far end or from the top end of the workpiece to the bottom end.

[0072] When processing thin-walled and mesh-like workpieces, the processing power should be controlled, and multiple low-power processing should be used to avoid workpiece deformation.

[0073] When the workpiece has a thick layer of oil stains, the oil stains can be pretreated, and the power should be adjusted during treatment to avoid open flames.

[0074] Workpieces with rust or uneven coating thickness should be scraped with high power in one pass to form a surface structure in one go, avoiding the accumulation of heat damage and structural destruction.

[0075] The smoke and exhaust fumes generated by scraping should be removed and collected by using side-blowing airflow and vacuum suction.

[0076] Before painting, any adhering substances on the workpiece surface must be removed to avoid affecting the coating performance.

[0077] During laser scratching, the workpiece surface should be protected to prevent impacts.

[0078] Workpieces that have been laser-scraped should be stored in a dry place; the workpieces should be coated within 6 hours after laser scratching to prevent surface corrosion.

[0079] After laser scratching is completed, testing and evaluation should be carried out according to the quality standards in Table 2.

[0080]

[0081] For visual inspection, the surface of the workpiece after laser scratching should not have obvious dirt or residual removal materials, and should not have new cracks, scratches, pits, or other defects, observed with the naked eye or a magnifying glass. When the user has cleanliness requirements for the workpiece, the cleanliness inspection shall be performed according to the user's requirements, and the acceptable cleanliness measurement result range is: Sa2-Sa3.

[0082] For surface roughness inspection, the surface roughness of laser-scraped workpieces shall be evaluated according to GB / T 1031. When laser scraping is a pre-coating process, the surface roughness inspection after treatment shall be carried out according to the process requirements of the subsequent process. Surface roughness can be measured using a probe-type profile measuring instrument or a three-dimensional optical profile measuring instrument. The acceptable surface roughness measurement result range is Ra20-Ra100.

[0083] For coating adhesion testing, when laser scraping is used to remove sprayed coatings, surface deposits, or other coatings with special adhesion requirements, the adhesion of the re-prepared coating after laser scraping should be tested. The adhesion between the laser-scraped substrate surface and the re-prepared coating should not be lower than the adhesion before coating removal and should meet the requirements in Table 2. A passing adhesion result is grade 0.

[0084] For hardness testing, the hardness after laser scratching and painting should meet the user's requirements. The sample, surface hardness measuring instrument, and test procedure should comply with the requirements of GB / T 6739. Hardness measurement result range: 1B-9B, HB, F, 1H-9H.

[0085] Based on the above-described preferred embodiments according to this application, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this application. The technical scope of this application is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A laser scratching process applied to metal surfaces, characterized in that, The scraping process described above uses a laser beam emitted from the laser head of a laser system to act on the metal surface to be treated, thereby simultaneously cleaning and texturing the metal surface. The laser system includes an optical path system for guiding and shaping the laser beam and causing the modulated laser beam to act on the surface of the metal material. The power density of the laser beam modulated by the optical path system is 50-76 MW / cm². 2 The laser beam has a spot size of 50-200 μm; The laser system also includes a feedback system, which is used to collect workpiece surface temperature information, laser beam angle and position information, and feed the collected information back to the processing unit of the laser system to adjust the emission power, angle and position of the laser head; The parameter selection for the laser scratching process includes the following steps: a) Determine the energy density threshold range by scratching the material properties; b) By conducting a scratching experiment, the energy density parameter was adjusted, and the damage threshold was determined. c) Identify the relationship between the damage threshold and surface morphology characteristics and properties; When the energy density exceeds the damage threshold corresponding to the desired morphological characteristics, the energy density boundary of laser scraping is determined; d) Based on the results of the scratching experiment, select and optimize the process parameters of laser wavelength, power density, laser duty cycle, scratching efficiency, and spot diameter. The formula for calculating laser power density is: Pd=P / S. Where: Pd—laser power density, unit MW / cm² 2 ; P—Average laser power, in MW; S—Spot area, in cm² 2 ; During the scraping operation, the process parameters also include: laser wavelength of 1.0-1.1μm and processing speed of 3-8m / s. 2 / h.

2. The laser scratching process applied to metal surfaces according to claim 1, characterized in that, The optical path system includes a collimating mirror (11), a first galvanometer (12), a second galvanometer (13), and a lens group (14).

3. The laser scratching process applied to metal surfaces according to claim 2, characterized in that, The feedback system includes a temperature management unit, which includes a temperature sensor for detecting the surface temperature information of the metal workpiece.

4. The laser scratching process applied to metal surfaces according to claim 3, characterized in that, The feedback system also includes a gyroscope mounted on the laser head for detecting the laser beam angle and position information.

5. A laser scratching process applied to metal surfaces according to any one of claims 1-4, characterized in that, The laser scraping process also uses a protective system to treat waste materials. The protective system includes a protective cover, an air blowing device, and a dust collection device. The protective cover is used to enclose the working space, the air blowing device is used to blow away the stripped material from the surface of the workpiece, and the dust collection device is used to absorb the stripped material and waste gas inside the protective cover.

6. The laser scratching process applied to metal surfaces according to claim 5, characterized in that, Before laser scraping, based on the material characteristics, shape and size, surface quality, and painting requirements of the steel structure workpiece to be scraped, it is necessary to determine the substrate to be retained and the dirt and coating to be removed, and to determine the process parameters according to the equipment and the properties of the laser beam.

7. The laser scratching process applied to metal surfaces according to claim 6, characterized in that, During and after the scraping operation, the workpiece needs to be protected. After the scraping operation, the workpiece also needs to be inspected. The inspection items include the workpiece appearance, surface roughness, coating adhesion and surface hardness.

8. The laser scratching process applied to metal surfaces according to claim 1, characterized in that, The metals to be processed include steel and its alloys, aluminum and its alloys, and titanium and its alloys.

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