Laser cleaning activation method and device before metal surface coating

Abstract

The invention discloses a laser cleaning activation method and device before metal surface coating, and belongs to the technical field of metal coating. The method comprises the steps that scanning parameters of a laser generator are adjusted based on laser cleaning activation requirements; a laser generator is used for emitting continuous laser beams corresponding to the scanning parameters; and the continuous laser beams are focused by a focusing system and then act on the surface of the metal matrix, so that the surface of the metal matrix is instantly melted and even gasified, and laser cleaning activation before metal surface coating is completed. The laser cleaning process is rapid and accurate, the production efficiency is remarkably improved, and the energy consumption is reduced. By accurately adjusting scanning parameters of the laser generator, such as laser power and scanning speed, accurate control on the surface depth, uniformity and roughness of the metal matrix can be realized. The metal surface subjected to laser cleaning and activation has higher activity, and the chemical bonding force between a coating and a metal base material can be remarkably enhanced.

Description

Technical Field

[0001] The invention belongs to the technical field of metal coating, and relates to a laser cleaning and activation method and device before metal surface coating. Background Art

[0002] In order to improve the corrosion resistance of the copper alloy surface, it is often necessary to coat the surface. As an effective surface protection method, coating technology can significantly improve the service life and performance stability of copper alloys in harsh environments. However, in the actual coating process of copper alloy parts, due to the dense and smooth characteristics of the copper alloy surface, the surface energy is relatively low, which makes it difficult for coating materials such as paint to adhere firmly to it. This lack of adhesion will directly affect the durability and protective effect of the coating, making copper alloy parts susceptible to corrosion and damage during application.

[0003] In view of the problem of poor coating adhesion on the surface of copper alloy, the traditional solution is to use sandblasting activation or chemical activation treatment. Sandblasting activation is a physical treatment method, which mainly uses high-speed jetting of hard particles such as sand to impact the surface of copper alloy, thereby removing surface pollution, increasing surface roughness, and thus improving coating adhesion. However, the sandblasting activation method has many shortcomings. On the one hand, this method mainly relies on manual operation, which not only consumes a lot of manpower, but also has low efficiency and cannot meet the needs of modern industry for automated and efficient production. On the other hand, a large amount of dust and noise pollution will be generated during the sandblasting activation process, which will harm the health of operators and the environment, and is not in line with the current green and environmentally friendly production concept. In addition, for thin plate parts, the strong mechanical impact during the sandblasting activation process may cause damage and deformation of the substrate, and additional leveling work is required, which not only increases the labor intensity, but also may cause product scrapping and increase production costs. Chemical activation uses chemicals such as acids and alkalis to corrode the surface of copper alloys to remove surface oxides and pollutants, while forming a certain degree of roughness, thereby improving coating adhesion. However, the chemical activation method also has many defects. On the one hand, the chemicals used in the chemical activation process are often corrosive, toxic, or flammable and explosive, posing a potential threat to the environment and operators. On the other hand, chemical activation may cause excessive corrosion on the surface of the copper alloy, affecting the dimensional accuracy and surface quality of the parts. In addition, the waste liquid and waste gas generated during the chemical activation process also need to be specially treated, increasing the cost of environmental governance. In view of the shortcomings of traditional copper alloy coating pretreatment methods, it is urgent to find a clean, efficient, and less damaging copper alloy coating pretreatment method. Summary of the invention

[0004] The purpose of the present invention is to solve the technical problems that the copper alloy pre-coating treatment method in the prior art may cause damage to the surface of parts and is not clean and efficient enough, and to provide a laser cleaning and activation method and device for metal surface before coating.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention discloses a laser cleaning and activation method for a metal surface before coating, comprising the following steps: Adjust the scanning parameters of the laser generator based on the laser cleaning and activation requirements; Using a laser generator to emit a continuous laser beam corresponding to the scanning parameters; The continuous laser beam is focused by a focusing system and then acts on the surface of the metal substrate, causing the surface of the metal substrate to melt or even vaporize instantly, thereby completing the laser cleaning and activation of the metal surface before coating.

[0006] Further improvements are: The scanning parameters include laser power, scanning speed, number of scans, pulse frequency and scanning spacing.

[0007] After completing the laser cleaning and activation of the metal surface before coating, observe whether the original metallic luster of the metal substrate is exposed on the surface of the metal substrate. If there is no oxide scale remaining, clean it, otherwise clean it again.

[0008] The metal matrix includes copper alloy, aluminum alloy and stainless steel.

[0009] In the second aspect, the present invention discloses a laser cleaning and activation device before metal surface coating for realizing the above-mentioned method, comprising a main control system; the main control system is connected to a laser generator and a two-dimensional movable workbench for placing a metal substrate; a scanning galvanometer is arranged downstream of the laser emitter, and a focusing lens is arranged downstream of the scanning galvanometer, and the focusing lens is arranged directly facing the metal substrate, so that the laser beam emitted by the laser generator passes through the scanning galvanometer and the focusing lens in sequence to reach the surface of the metal substrate; the laser generator and the scanning galvanometer are both connected to the main control system.

[0010] A smoke and dust purification system is arranged adjacent to the two-dimensional movable workbench.

[0011] The scanning galvanometer includes a pair of high-speed rotatable reflectors; the main control system controls the rotation angle of the reflectors to achieve rapid deflection of the laser beam in a two-dimensional plane, thereby comprehensively scanning the surface of the metal substrate.

[0012] The two-dimensional movable workbench is provided with a positioning system for controlling the position of the metal substrate.

[0013] The focusing lens is an adjustable focus lens, which is used to adjust the laser beam to adapt to metal substrates with different thicknesses and curvatures; the focusing lens is connected to a control system.

[0014] The focusing lens is a self-focusing lens, a moiré lens, an Optotune adjustable focus lens or a dynamic focusing lens.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The invention discloses a laser cleaning and activation method before coating of a metal surface. The invention adopts laser cleaning and activation technology, does not need to use chemical solvents, and avoids environmental pollution problems that may be generated during chemical cleaning. At the same time, the laser cleaning process is fast and accurate, significantly improves production efficiency, and reduces energy consumption. By accurately adjusting the scanning parameters of the laser generator, such as laser power, scanning speed, etc., the depth, uniformity and roughness of the metal substrate surface can be accurately controlled. This can not only effectively remove pollutants such as dirt, grease, oxide scale, etc. on the metal surface, but also expose fresh and highly active metal substrates, providing ideal substrate conditions for subsequent coating processes. The metal surface after laser cleaning and activation has higher activity, which can significantly enhance the chemical bonding force between the coating and the metal substrate. At the same time, by adjusting the different roughness surfaces formed by laser parameters, the mechanical anchoring effect between the coating and the metal substrate can also be increased, thereby improving the adhesion and durability of the coating. The method of the invention is applicable to a variety of metal materials, such as copper alloys, aluminum alloys, stainless steel, etc., and can effectively clean and activate metal parts of different shapes and sizes. The laser cleaning and activation technology does not require the use of a large amount of chemical solvents or consumable tools, reducing material costs and equipment maintenance costs. At the same time, since the laser cleaning process is fast and accurate, it can significantly reduce labor costs and time costs. The laser cleaning and activation method for metal surface coating proposed in the present invention not only has significant advantages such as high efficiency and environmental protection, high cleaning quality, and enhanced coating adhesion, but is also applicable to a variety of metal materials and can significantly reduce production costs, and has broad application prospects and market value.

[0016] Furthermore, the scanning parameters include laser power, scanning speed, number of scans, pulse frequency and scanning spacing. The laser power affects the degree of laser cleaning. Appropriate laser power can ensure that the etching depth of the copper alloy surface is moderate, the cleaning is thorough, and the adhesion of the subsequent coating is improved. The scanning speed affects the residence time of the laser point on the substrate surface, thereby affecting the etching depth and cleaning efficiency. The scanning spacing determines the regional distribution of laser cleaning on the copper alloy surface. The appropriate scanning spacing can ensure that the copper alloy surface exposes enough active copper areas and improves the bonding strength between the coating and the substrate. The present invention also screens and determines the best combination of laser parameters through experiments and optimization steps to ensure that the copper alloy surface obtains a highly active, efficient and low-energy cleaning and activation effect.

[0017] The invention discloses a laser cleaning and activation device before metal surface coating. The device can realize efficient and accurate cleaning and activation of the metal substrate surface by accurately controlling the laser beam generated by the laser generator through the main control system, and combining the fast scanning function of the scanning galvanometer. This non-contact cleaning method not only avoids the mechanical damage or chemical pollution that may be caused by the traditional cleaning method, but also significantly improves the efficiency and quality of cleaning and activation. Due to the flexible regulation of the scanning galvanometer, the device can flexibly adjust the scanning path and power density of the laser beam according to different metal substrate shapes and sizes, as well as different cleaning and activation requirements. This high degree of flexibility enables the device to be applicable to the surface treatment of a variety of metal materials, greatly broadening its application range. Through the integrated control of the main control system, the device can realize the automation and intelligence of the laser cleaning and activation process. This not only reduces the difficulty of operation and labor costs, but also improves the consistency of production efficiency and product quality. At the same time, the main control system can also dynamically adjust and optimize the cleaning and activation process according to the feedback data of real-time monitoring, so as to further improve the overall performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 This is a flow chart of a laser cleaning and activation method for a metal surface before coating in the present invention; Figure 2 It is a schematic structural diagram of a laser cleaning and activation device before metal surface coating in the present invention; Figure 3 This is a surface image of the copper alloy before laser cleaning and activation in an embodiment of the present invention; Figure 4 This is a surface image of the copper alloy after laser cleaning and activation in an embodiment of the present invention; Figure 5 Schematic diagram of the combination of the copper alloy surface and the primer layer after laser cleaning and activation in an embodiment of the present invention; Figure 6 (a) is the copper alloy surface after laser cleaning and activation in an embodiment of the present invention; Figure 6 (b) is a microscopic schematic diagram of the copper alloy surface after laser cleaning and activation in an embodiment of the present invention; Figure 7 (a) is the copper alloy surface activated by sandblasting; Figure 7 (b) is the copper alloy surface coated with varnish after laser cleaning and activation in an embodiment of the present invention; Figure 8 (a) is a graph showing the adhesion test after coating with polyurethane varnish after laser cleaning and activation in an embodiment of the present invention; Figure 8 (b) is a graph showing the adhesion of the acrylic polyurethane enamel after laser cleaning and activation in an embodiment of the present invention.

[0020] Among them: 1-main control system; 2-laser generator; 3-scanning galvanometer; 4-focusing lens; 5-two-dimensional mobile workbench; 6-smoke purification system; 7-oxide layer; 8-metal substrate; 9-active copper alloy surface after laser cleaning and activation; 10-base coating; 11-binding surface between base coating and surface after laser cleaning and activation; 12-chemical bond force and mechanical anchoring force. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0024] The present invention is further described in detail below in conjunction with the accompanying drawings: See also Figure 1 The embodiment of the present invention discloses a laser cleaning and activation method for a metal surface before coating, comprising the following steps: Step 1: Based on the laser cleaning and activation requirements, the scanning parameters of the laser generator are adjusted; the scanning parameters include laser power, scanning speed, number of scans, pulse frequency and scanning spacing.

[0025] Step 2, using a laser generator to emit a continuous laser beam corresponding to the scanning parameters; Step 3: The continuous laser beam is focused by a focusing system and then acts on the surface of the metal substrate, so that the surface of the metal substrate is instantly melted or even vaporized, completing the laser cleaning and activation of the metal surface before coating. The metal substrate includes copper alloy, aluminum alloy and stainless steel.

[0026] Step 4: After completing the laser cleaning and activation of the metal surface before coating, observe the surface of the metal substrate to see whether the original metallic luster of the metal substrate is exposed. If there is no oxide scale left, clean it, otherwise clean it again.

[0027] Example 1 For copper alloy in H62 Y2 state, in order to achieve a coating with good adhesion (paint layer adhesion reaches level 1, GB / 9286), laser cleaning and activation before coating can use a light pulse fiber laser with a wavelength of 1064nm. The activation parameters are: laser average power 20-30W, scanning speed 3000mm / s-5000mm / s, scanning spacing 0.2-0.3mm, pulse frequency 40-60kHz, and scanning times 2 times (vertical and horizontal scanning).

[0028] The invention discloses a laser cleaning and activation method before coating of a metal surface. The invention adopts laser cleaning and activation technology, does not need to use chemical solvents, and avoids environmental pollution problems that may be generated during chemical cleaning. At the same time, the laser cleaning process is fast and accurate, significantly improves production efficiency, and reduces energy consumption. By accurately adjusting the scanning parameters of the laser generator, such as laser power, scanning speed, etc., the depth, uniformity and roughness of the metal substrate surface can be accurately controlled. This can not only effectively remove pollutants such as dirt, grease, oxide scale, etc. on the metal surface, but also expose fresh and highly active metal substrates, providing ideal substrate conditions for subsequent coating processes. The metal surface after laser cleaning and activation has higher activity, which can significantly enhance the chemical bonding force between the coating and the metal substrate. At the same time, by adjusting the different roughness surfaces formed by laser parameters, the mechanical anchoring effect between the coating and the metal substrate can also be increased, thereby improving the adhesion and durability of the coating. The method of the invention is applicable to a variety of metal materials, such as copper alloys, aluminum alloys, stainless steel, etc., and can effectively clean and activate metal parts of different shapes and sizes. The laser cleaning and activation technology does not require the use of a large amount of chemical solvents or consumable tools, reducing material costs and equipment maintenance costs. At the same time, since the laser cleaning process is fast and accurate, it can significantly reduce labor costs and time costs. The laser cleaning and activation method for metal surface coating proposed in the present invention not only has significant advantages such as high efficiency and environmental protection, high cleaning quality, and enhanced coating adhesion, but is also applicable to a variety of metal materials and can significantly reduce production costs, and has broad application prospects and market value.

[0029] See also Figure 2The embodiment of the present invention discloses a laser cleaning and activation device for metal surface coating before implementing the above method, comprising a main control system 1; the main control system 1 is connected to a laser generator 2 and a two-dimensional movable workbench 5 for placing a metal substrate 8; a smoke purification system 6 is arranged adjacent to the two-dimensional movable workbench 5. A scanning galvanometer 3 is arranged downstream of the laser emitter 2, and a focusing lens 4 is arranged downstream of the scanning galvanometer 3. The focusing lens 4 is arranged directly opposite to the metal substrate 8, so that the laser beam emitted by the laser generator 2 passes through the scanning galvanometer 3 and the focusing lens 4 in sequence to reach the surface of the metal substrate 8; the laser generator 2 and the scanning galvanometer 3 are both connected to the main control system 1. The scanning galvanometer 3 includes a pair of high-speed rotating reflectors; the main control system 1 realizes the rapid deflection of the laser beam in a two-dimensional plane by controlling the rotation angle of the reflector, thereby comprehensively scanning the surface of the metal substrate 8. The focusing lens 4 is an adjustable focus lens, which is used to adjust the laser beam to adapt to metal substrates 8 of different thicknesses and curvatures; the focusing lens 4 is connected to the control system. The focusing lens 4 is a self-focusing lens, a moiré lens, an Optotune adjustable focus lens or a dynamic focusing lens. The two-dimensional moving workbench 5 is provided with a positioning system for controlling the position of the metal substrate 8.

[0030] The laser emitted by the laser is deflected and focused by the scanning galvanometer and focusing lens. The focused pulse laser acts on the surface of the copper alloy to clean and activate the copper alloy. After cleaning and activation, a clean and highly active copper alloy is exposed.

[0031] When the active surface after laser cleaning and activation is coated, the base coating can form good adhesion with the copper alloy surface, such as Figure 3 , Figure 4 and Figure 5 shown.

[0032] The beneficial effects of the present invention are verified as follows: The copper alloy substrate after degreasing is placed on the two-dimensional workbench 5, the focal length is adjusted, the laser power, scanning speed, scanning interval and pulse frequency of laser cleaning are set, and the copper alloy surface is cleaned and activated. The copper alloy surface after laser cleaning and activation and the microscopic diagram are as follows: Figure 6 (a) and Figure 6 (b) As shown. The activated copper alloy is coated to obtain a coating with uniform appearance and good adhesion. The appearance comparison diagram of the copper alloy coated with varnish after laser cleaning and activation and the copper alloy coated with varnish after sandblasting activation is shown in Figure 7 (a) and Figure 7 (b) Schematic diagram of the cross-cut test adhesion after spraying polyurethane varnish and acrylic polyurethane enamel respectively after laser cleaning and activation, as shown in Figure 8 (a) and Figure 8 (b) shown.

[0033] The working principle of the present invention is as follows: Before coating the copper alloy surface, the surface is scanned with a laser. This process relies on the principle of laser ablation. The laser generator generates a high-energy continuous laser beam. The focused laser acts on the surface of the copper alloy, causing the surface material to melt or even vaporize instantly, forming an effect similar to etching. On the one hand, it can remove dirt and oxide scale on the surface of the copper alloy, expose fresh and highly active copper alloys, and enhance the chemical bond between the substrate and the paint; on the other hand, by adjusting the laser scanning parameters, the substrate surface with different roughness can be obtained, providing active centers for the subsequent coating process and forming a mechanical anchoring effect. During the laser cleaning and activation process of the copper alloy surface, the activation degree of the copper alloy surface can be controlled by adjusting the laser parameters to form a surface with different active effects. The parameters that affect the activation effect of the copper alloy surface include laser power, scanning speed, number of scans, pulse frequency, and scanning spacing. Among them, the average power of the laser scan affects the degree of laser cleaning. The greater the average power, the deeper the etching of the copper alloy surface, the more thorough the cleaning degree, and the stronger the adhesion of the subsequent coating; but if the average power is too large, a loose oxide layer will be produced on the surface of the copper alloy, affecting the adhesion of the subsequent coating. If the scanning speed is slow, the laser point stays on the substrate surface for a long time, the substrate is deeply etched, but the cleaning efficiency is low; on the contrary, if the scanning speed is fast, the single point stays for a short time, the etching degree of the substrate is shallow, and the cleaning is not thorough; the scanning spacing determines the area of ​​laser cleaning on the copper alloy surface. The larger the scanning spacing, the more dispersed the laser cleaning area, the smaller the exposed active copper area, the fewer active copper atoms per unit area that chemically bond with the coating molecules, and the weaker the coating adhesion; if the scanning spacing is too small, the area of ​​copper alloy surface cleaning is dense, and the laser point concentration leads to local overheating and the appearance of loose oxide layer, which affects the subsequent coating adhesion. Therefore, in the actual operation process, it is necessary to obtain the copper alloy laser cleaning activation parameters with high surface activity, high efficiency and low energy consumption through experimental screening.

[0034] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A laser cleaning and activation method for metal surface before coating, characterized in that: The following steps are involved: Adjust the scanning parameters of the laser generator based on the laser cleaning and activation requirements; Using a laser generator to emit a continuous laser beam corresponding to the scanning parameters; The continuous laser beam is focused by a focusing system and then acts on the surface of the metal substrate, causing the surface of the metal substrate to melt or even vaporize instantly, thereby completing the laser cleaning and activation of the metal surface before coating.

2. The laser cleaning and activation method for metal surface before coating according to claim 1, characterized in that: The scanning parameters include laser power, scanning speed, number of scans, pulse frequency and scanning spacing.

3. The laser cleaning and activation method for metal surface before coating according to claim 2, characterized in that: After completing the laser cleaning and activation of the metal surface before coating, observe whether the original metallic luster of the metal substrate is exposed on the surface of the metal substrate. If there is no oxide scale remaining, clean it, otherwise clean it again.

4. The laser cleaning and activation method for metal surface before coating according to claim 1, characterized in that: The metal matrix includes copper alloy, aluminum alloy and stainless steel.

5. A laser cleaning and activation device for metal surface before coating for implementing the method according to any one of claims 1 to 4, characterized in that: The invention comprises a main control system (1); the main control system (1) is connected to a laser generator (2) and a two-dimensional movable workbench (5) for placing a metal substrate (8); a scanning galvanometer (3) is arranged downstream of the laser emitter (2); a focusing lens (4) is arranged downstream of the scanning galvanometer (3); the focusing lens (4) is arranged facing the metal substrate (8), so that the laser beam emitted by the laser generator (2) passes through the scanning galvanometer (3) and the focusing lens (4) in sequence to reach the surface of the metal substrate (8); the laser generator (2) and the scanning galvanometer (3) are both connected to the main control system (1).

6. The laser cleaning and activation device for metal surface before coating according to claim 5, characterized in that: A smoke and dust purification system (6) is arranged adjacent to the two-dimensional movable workbench (5).

7. The laser cleaning and activation device for metal surface before coating according to claim 5, characterized in that: The scanning galvanometer (3) comprises a pair of high-speed rotatable reflectors; the main control system (1) controls the rotation angle of the reflectors to achieve rapid deflection of the laser beam in a two-dimensional plane, thereby fully scanning the surface of the metal substrate (8).

8. The laser cleaning and activation device for metal surface before coating according to claim 5, characterized in that: The two-dimensional movable workbench (5) is provided with a positioning system for controlling the position of the metal substrate (8).

9. The laser cleaning and activation device for metal surface before coating according to claim 5, characterized in that: The focusing lens (4) is a focus-adjustable lens, used for adjusting the laser beam to adapt to metal substrates (8) of different thicknesses and curvatures; the focusing lens (4) is connected to a control system.

10. The laser cleaning and activation device for metal surface before coating according to claim 9, characterized in that: The focusing lens (4) is a self-focusing lens, a moiré lens, an Optotune adjustable focus lens or a dynamic focusing lens.

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