High-voltage copper alloy contact laser cleaning method

Abstract

The invention provides a laser cleaning method for a high-voltage copper alloy contact, which comprises the following steps of: (1) obtaining light spots with uniformly distributed laser energy by adopting an optical shaping technology, avoiding ablation of a cleaned surface caused by over-high local energy density, and ensuring relatively low roughness of the laser cleaned surface; (2) a light beam with the large focal depth is designed so that the consistency of the laser spot size and the energy density can be guaranteed under the small-amplitude change of the laser cleaning distance, and the uniform cleaning effect can be achieved; (3) an oily carbon black solution is sprayed to the surface of the copper alloy through a spraying can; and (4) laser cleaning parameters of the high-voltage copper alloy contact are set, and laser cleaning is conducted on the high-voltage copper alloy contact. According to the laser cleaning method for the high-voltage copper alloy contact, low surface roughness can be obtained, and the contact through-flow effect can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of laser cleaning of high-voltage contacts, and in particular relates to a method for laser cleaning of high-voltage copper alloy contacts. Background Art

[0002] High-voltage copper alloy contacts are exposed to wind and rain and alternating hot and cold conditions for a long time, and the surface is prone to oxidation, which leads to increased resistance and poor flow effect, posing a great hidden danger to the operation of the power grid! In order to avoid greater losses caused by contact oxidation, power companies often need to shut down the power supply to sandpaper polish the oxidized parts to improve their contact flow effect. On the one hand, this requires power outages, resulting in economic losses. On the other hand, sandpaper polishing is labor-intensive and has high surface roughness, which affects the subsequent flow effect of the copper alloy contacts. Therefore, it is urgent to develop new copper alloy contact cleaning technologies.

[0003] Laser cleaning is an advanced technology that uses high peak power laser to irradiate oxidized or rusted parts. After the oxide layer or substrate absorbs the laser energy, the temperature rises sharply, producing a series of physical effects, such as swelling, gasification, thermal shock and thermal vibration, sonic shattering and ablation vaporization, etc., which eventually separates the oxide rust layer from the substrate, achieving cleaning without damaging the substrate. Compared with traditional cleaning and rust removal processes such as grinding wheels, laser cleaning has the characteristics of no contact and long-distance operation. It is particularly suitable for live cleaning of high-voltage contacts, and it is clean and pollution-free, which is expected to provide a new method for cleaning power equipment. However, due to the low absorption rate of copper alloy to laser, the existing pulse laser cleaning technology requires a higher laser power to achieve laser cleaning of the copper alloy surface. Its high peak power will form micro-ablation pits on the copper alloy surface, making the copper alloy surface rough. Subsequent grinding is required to reduce the surface roughness and improve the contact flow effect of the contact. In addition, pulse laser has the disadvantage of large power attenuation in long-distance transmission. Compared with pulse laser, continuous laser has low attenuation in long-distance transmission, which makes it easier to achieve long-distance live cleaning of copper alloy contacts. However, continuous laser cleaning mainly uses the thermal effect of the laser to remove the oxide layer. How to avoid high-temperature oxidation of the copper alloy surface and uneven local cleaning during the cleaning process and obtain lower roughness and good contact effect are the key difficulties of this technology. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a method for laser cleaning of high voltage copper alloy contacts, which can obtain lower surface roughness and improve contact flow effect.

[0005] The present invention specifically provides a method for laser cleaning of high voltage copper alloy contacts, and the method for laser cleaning of high voltage contacts comprises the following steps:

[0006] Step (1): using optical shaping technology to obtain a spot with uniform laser energy distribution, avoiding ablation of the cleaning surface caused by excessive local energy density, and ensuring a low laser cleaning surface roughness;

[0007] Step (2): Design a beam with a larger focal depth to ensure the consistency of the laser spot size and energy density when the laser cleaning distance changes slightly, so as to obtain a uniform cleaning effect;

[0008] Step (3): spraying the oily carbon black solution on the surface of the copper alloy using a spray pot;

[0009] Step (4): Setting the laser cleaning parameters for the high voltage copper alloy contacts and performing laser cleaning on the high voltage copper alloy contacts.

[0010] Furthermore, in step (1), the laser beam is adjusted to a flat-top light, thereby obtaining a light spot with uniform laser energy distribution.

[0011] Furthermore, in step (3), a spray pot is used to spray a uniformly distributed oily carbon black solution on the surface of the copper alloy.

[0012] Furthermore, the specific method for setting the laser cleaning parameters of the high voltage copper alloy contact in step (4) is:

[0013] A laser cleaning process experiment was designed to test the roughness and oxygen content of the copper alloy surface under different laser cleaning parameters. The laser cleaning parameter range with low laser cleaning roughness and oxygen content was selected to finally set the laser cleaning parameters for high-voltage copper alloy contacts.

[0014] Furthermore, the roughness of the copper alloy surface was measured by laser confocal microscopy, and the oxygen content of the copper alloy surface was tested by XRF.

[0015] Compared with the prior art, the beneficial effects are: the present invention utilizes continuous laser cleaning to achieve long-distance live surface cleaning of high-voltage contacts, thereby avoiding economic losses caused by power outages; on the other hand, by designing the laser cleaning optical path and carbon black surface pretreatment, a uniform cleaning effect can be obtained on the copper alloy surface, forming a contact surface with lower roughness, thereby improving subsequent contact flow effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a working flow chart of a method for laser cleaning of high voltage copper alloy contacts of the present invention;

[0017] Figure 2 This is the energy distribution diagram of the laser cleaning beam;

[0018] Figure 3 Schematic diagram of the focal depth of the laser beam. DETAILED DESCRIPTION

[0019] The specific implementation of a method for laser cleaning of high voltage copper alloy contacts of the present invention is described in detail below with reference to the accompanying drawings.

[0020] like Figure 1 As shown, the method for laser cleaning of high voltage copper alloy contacts of the present invention comprises the following steps:

[0021] Step (1): using optical shaping technology to adjust the laser beam into a flat top light, obtain a light spot with uniform laser energy distribution, avoid ablation of the cleaning surface caused by excessive local energy density, and ensure a low laser cleaning surface roughness;

[0022] Step (2): Design a beam with a large focal depth (focal depth refers to the distance between two light spots with a diameter change of 5% on both sides of the focus) to ensure the consistency of laser spot size and energy density when the laser cleaning distance changes slightly, so as to obtain a uniform cleaning effect;

[0023] Step (3): spraying an oily carbon black solution on the surface of the copper alloy with a spray bottle. On the one hand, the carbon black can form a reducing atmosphere on the surface of the copper alloy during the laser cleaning process and react with oxygen in the air to prevent the surface of the copper alloy contact from being oxidized at high temperatures. On the other hand, it can improve the absorption efficiency of the copper alloy to the laser, avoid damage to optical components caused by laser reflection on the surface of the copper alloy, and improve the laser cleaning effect. In addition, the evenly distributed carbon black coating can avoid the difference in laser absorption rate caused by uneven oxides on the surface of the copper alloy, thereby obtaining a uniform cleaning effect.

[0024] Step (4): Design a laser cleaning process test to test the roughness and oxygen content of the copper alloy surface under different laser cleaning parameters, preferably select a process parameter range with low laser cleaning roughness and oxygen content, set the laser cleaning parameters for the high-voltage copper alloy contact, and perform laser cleaning on the high-voltage copper alloy contact.

[0025] In general, the present invention adopts long-distance laser cleaning technology to obtain a copper alloy cleaning surface with low roughness and low oxygen content, and improves the contact flow effect of high-voltage contacts. Continuous laser can be used to reduce long-distance transmission losses; by designing a laser spot with uniform energy distribution and a large focal depth design, and adopting pretreatment of spraying oily carbon black and optimization of cleaning process parameters, the uniformity of copper alloy contact cleaning can be effectively guaranteed, and a lower surface roughness and oxygen content can be obtained, thereby improving the contact flow effect of high-voltage contacts.

[0026] Example

[0027] Figure 2 is the laser beam energy distribution diagram, where Figure 2 (a) is the energy distribution diagram of Gaussian spot, Figure 2 (b) is the energy distribution diagram of the flat-top spot.

[0028] Figure 3 is a schematic diagram of the focal depth of the laser beam, where Figure 3 (a) is a schematic diagram of the small focal depth of the laser beam. Figure 3 (b) Schematic diagram of the large focal depth of the laser beam.

[0029] Laser cleaning technology is used to clean high voltage contacts and obtain a cleaned surface with low roughness and oxygen content. The specific implementation steps include:

[0030] Step a: Design a continuous laser cleaning device, and adjust the laser beam into a flat top light through spot shaping. Its energy distribution is as follows: Figure 2 As shown in (b), the beam diameter is 2 mm and a large focal depth design is adopted, such as Figure 3 (b) shows that the focal depth is 20 mm;

[0031] Step b: setting the laser cleaning parameters, the laser power is 2000W, the laser scanning line width is 60mm, which is the width of the copper alloy contact, the laser scanning speed is 10m / s, and the cleaning head travel speed is 0.5m / min;

[0032] Step c: After the laser cleaning experiment is completed, a laser confocal microscope is used to observe the three-dimensional morphology of the surface of the above-mentioned numbered samples and measure the average surface roughness value (Ra) of the samples, and XRF is used to test the oxygen content on the surface of the copper alloy;

[0033] Step d: Evaluate the surface roughness, oxygen content and contact current flow effect of the high voltage contact after laser cleaning, determine the range of laser cleaning process parameters for the high voltage contact, and establish laser cleaning process specifications.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not intended to limit the present invention. A person skilled in the art should understand that the specific implementation of the present invention can be modified or replaced by equivalents, but these modifications or changes are within the scope of protection of the pending claims.

Claims

1. A method for laser cleaning of high voltage copper alloy contacts, characterized in that: The method for laser cleaning of high voltage copper alloy contacts comprises the following steps: Step (1): using optical shaping technology to obtain a light spot with uniform laser energy distribution, avoiding ablation of the cleaning surface caused by excessive local energy density, and ensuring a low laser cleaning surface roughness; Step (2): Design a beam with a larger focal depth to ensure the consistency of the laser spot size and energy density when the laser cleaning distance changes slightly, so as to obtain a uniform cleaning effect; Step (3): spraying the oily carbon black solution on the surface of the copper alloy using a spray pot; Step (4): Setting the laser cleaning parameters for the high voltage copper alloy contacts and performing laser cleaning on the high voltage copper alloy contacts.

2. The method for laser cleaning of high voltage copper alloy contacts according to claim 1, characterized in that: In step (1), the laser beam is adjusted to a flat top light, thereby obtaining a light spot with uniform laser energy distribution.

3. The method for laser cleaning of high voltage copper alloy contacts according to claim 2, characterized in that: In step (3), a spray pot is used to spray an evenly distributed oily carbon black solution on the surface of the copper alloy.

4. The method for laser cleaning of high voltage copper alloy contacts according to claim 3, characterized in that: The specific method for setting the laser cleaning parameters of the high voltage copper alloy contact in step (4) is: A laser cleaning process experiment was designed to test the roughness and oxygen content of the copper alloy surface under different laser cleaning parameters. The laser cleaning parameter range with low laser cleaning roughness and oxygen content was selected to finally set the laser cleaning parameters for high-voltage copper alloy contacts.

5. The method for laser cleaning of high voltage copper alloy contacts according to claim 4, characterized in that: Laser confocal microscopy was used to measure the roughness of the copper alloy surface; XRF was used to test the oxygen content of the copper alloy surface.

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