A laser repair method for localized scratches on the hard anodized layer of aluminum alloy parts

Abstract

This invention relates to the field of laser milling and laser polishing technology for metals and metal oxides, specifically a laser repair method for localized scratches on the hard anodized layer of aluminum alloy parts, comprising the following steps: Step (1) using laser scanning to mill and remove the hard anodized layer at the damaged area of ​​the aluminum alloy part; Step (2) using laser scanning to polish the damaged area of ​​the aluminum alloy part after removing the hard anodized layer to the required surface roughness; Step (3) placing the damaged area of ​​the aluminum alloy part after removing the hard anodized layer in an electrolyte, forming an aluminum oxide film through electrolysis. This method significantly reduces environmental pollution during the process and enables localized removal of scratches, improving repair efficiency; it can replace manual sandpaper polishing, precisely controlling part dimensions and surface roughness, and avoiding dimensional deviations and inconsistencies caused by manual operation.

Description

Technical Field

[0001] This invention relates to the field of laser milling and laser polishing technology for metals and metal oxides, specifically a laser repair method for localized scratches on the hard anodized layer of aluminum alloy parts. Background Technology

[0002] For aluminum alloy parts used in aerospace products, the hard anodized layer on its surface is a crucial functional structure ensuring the parts' wear resistance and corrosion resistance, among other service performance characteristics. Currently, the mainstream technology for preparing the hard anodized layer of aluminum alloy involves immersing the entire part in an electrolyte solution, where an anodized layer composed of aluminum oxide is generated on the part's surface through an electrolytic reaction. During the use of these aluminum alloy parts, surface scratches are unavoidable. Failure to repair these scratches will severely impact the safety and service life of aerospace products. For repairing these locally scratched aluminum alloy parts, the current technique involves using chemical milling and alkaline chipping to remove the original anodized layer from the entire aluminum alloy part, followed by manual polishing of the surface, then re-preparing the anodized layer, and finally, manual polishing again to achieve acceptable part dimensions and surface roughness. This method is complex, environmentally polluting, heavily reliant on worker experience, and suffers from poor processing consistency. Especially for parts requiring multiple repairs, this process gradually reduces the size of the aluminum alloy substrate, severely impacting the part's overall lifespan.

[0003] A search revealed that patent CN112296528A discloses a method for laser removal of a film layer on the surface of aluminum alloy. Its embodiments report that the surface roughness of the aluminum alloy after implementing this method can reach 2.4 μm. This roughness index cannot meet the requirements of the subsequent anodizing process involved in this invention. Furthermore, the thinnest film removed is 10 μm, which cannot meet the dimensional accuracy required for part repair involved in this invention. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a laser repair method for localized scratches on the hard anodized layer of aluminum alloy parts. By employing laser milling and laser polishing technologies to locally repair the scratched area, compared to traditional chemical milling and manual grinding methods, this method significantly reduces environmental pollution during production, improves processing consistency, and features full automation, non-contact operation, high efficiency, and high precision.

[0005] The technical problem to be solved by this invention is achieved by the following technical solution:

[0006] A laser repair method for localized scratches on the hard anodized layer of aluminum alloy parts includes the following steps:

[0007] Step (1) The hard anodized layer in the damaged area of ​​the aluminum alloy part is removed by laser milling using laser scanning.

[0008] Step (2) Laser polishing is performed on the damaged area of ​​the aluminum alloy part after the removal of the hard anodized layer using laser scanning to achieve the required surface roughness;

[0009] Step (3) Place the damaged area of ​​the aluminum alloy part after removing the hard anodized layer in the electrolyte to form an aluminum oxide film through electrolysis;

[0010] Step (4) Dimensionally measure the prepared coating, requiring the coating thickness to be greater than the original coating thickness;

[0011] Step (5) uses the same laser scanning method as step (1) to remove the coating processing allowance in step (4);

[0012] Step (6) uses the same laser scanning method as in step (2) to polish the coating of the aluminum alloy parts after removing the coating machining allowance to the required surface roughness.

[0013] Preferably, the laser scanning methods in steps (1) and (2) include parallel line laser scanning, cross grid laser scanning, and cross line laser scanning.

[0014] Preferably, the laser scanning process parameters in step (1) include a laser wavelength of 1030-1070nm, a laser pulse width of 500fs-15ps, a laser repetition frequency of 100kHz-1MHz, a laser average power of 30-50W, a spot diameter of 20-50μm, and a beam scanning speed of 200mm / s-500mm / s.

[0015] Preferably, the distance between adjacent laser scanning paths in step (1) is 10-40 μm.

[0016] Preferably, the laser scanning milling machining accuracy requirement in step (1) is ±5μm.

[0017] Preferably, the laser scanning process parameters in step (2) include a laser wavelength of 1030-1070nm, a laser pulse width of 500fs-15ps, a laser repetition frequency of 500kHz-1MHz, a laser average power of 5-10W, a spot diameter of 20-50μm, and a beam scanning speed of 1000mm / s-2000mm / s.

[0018] Preferably, the distance between adjacent laser scanning paths in step (2) is 2-10 μm.

[0019] Preferably, the roughness after laser scanning polishing in step (2) is required to be no greater than 0.5 μm.

[0020] Preferably, the machining allowance thickness range in step (4) is 50-200 μm.

[0021] Preferably, the machining accuracy and roughness in step (6) are the same as those in steps (1) and (2).

[0022] The beneficial effects of this invention are:

[0023] First, laser milling technology is used to replace the original chemical milling and alkaline chipping removal of the anodized layer, which greatly reduces environmental pollution in the process and can achieve local removal of scratched areas, thus improving repair efficiency.

[0024] Secondly, laser milling technology is used to mill and polish the re-anodized parts, which can replace manual sanding and precisely control the size and surface roughness of the parts, avoiding the problems of dimensional deviation and poor consistency caused by manual operation. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0026] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0027] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0028] like Figure 1 As shown, a laser repair method for localized scratches on the hard anodized layer of aluminum alloy parts involves first using a scanning galvanometer to move a laser beam at high speed along a predetermined path, removing the anodized layer in the damaged area point by point and layer by layer. By precisely controlling processing parameters, damage to the substrate is reduced or even avoided. Further laser polishing optimizes the surface roughness of the substrate. After the anodized layer is re-prepared, a similar laser scanning method is used to remove the processing allowance layer by layer, gradually reducing the surface roughness of the anodized layer. Once the part dimensions meet the requirements, the surface is further polished by adjusting the laser processing parameters to satisfy the surface roughness requirements.

[0029] The specific steps are as follows:

[0030] Step (1) Removal of anodized layer in damaged area: The damaged aluminum alloy parts are processed by laser scanning. The hard anodized layer in the damaged area of ​​the aluminum alloy parts is removed by laser milling. The processing accuracy is required to reach ±5μm.

[0031] Furthermore, the specific process parameters for the laser scanning method include: laser wavelength of 1030-1070nm, laser pulse width of 500fs-15ps, laser repetition frequency of 100kHz-1MHz, laser average power of 30-50W, spot diameter of 20-50μm, and beam scanning speed of 200mm / s-500mm / s.

[0032] In addition, laser scanning methods include parallel lines, cross grids, and intersecting lines, with the spacing between adjacent laser scanning paths ranging from 10 to 40 μm.

[0033] Step (2) Polishing of aluminum alloy substrate: The damaged area of ​​the aluminum alloy part after the removal of the hard anodized layer is laser-polished to the required surface roughness by laser scanning. The roughness requirement is not greater than 0.5μm.

[0034] Furthermore, the specific process parameters for the laser scanning method include: laser wavelength of 1030-1070nm, laser pulse width of 500fs-15ps, laser repetition frequency of 500kHz-1MHz, laser average power of 5-10W, spot diameter of 20-50μm, and beam scanning speed of 1000mm / s-2000mm / s.

[0035] In addition, laser scanning methods include parallel lines, cross grids, and intersecting lines, with the spacing between adjacent laser scanning paths ranging from 2 to 10 μm.

[0036] Step (3) Preparation of selective anodized coating: The damaged area of ​​the aluminum alloy part after the hard anodized layer is removed is placed in the electrolyte, and an aluminum oxide film is formed through electrolysis.

[0037] Step (4) Dimensionally measure the prepared coating. The coating thickness should be greater than the original coating thickness, and the machining allowance thickness range should be 50-200 μm.

[0038] Step (5) Anodized layer removal: The coating processing allowance in step (4) is removed using the same laser scanning method and process parameters as in step (1).

[0039] Step (6) Anodized layer polishing: The aluminum alloy parts after removing the coating processing allowance are polished to the required surface roughness using the same laser scanning method and process parameters as in step (2). The processing accuracy is required to reach ±5μm and the roughness is required to be no greater than 0.5μm.

[0040] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely prisms of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A laser repair method for localized scratches on the hard anodized layer of aluminum alloy parts, characterized in that: Includes the following steps: Step (1) The hard anodized layer in the damaged area of ​​the aluminum alloy part is removed by laser milling using laser scanning. The laser scanning process parameters in step (1) include a laser wavelength of 1030-1070 nm, a laser pulse width of 500 fs-15 ps, a laser repetition frequency of 100 kHz-1 MHz, an average laser power of 30-50 W, a spot diameter of 20-50 μm, a beam scanning speed of 200 mm / s-500 mm / s, a laser adjacent scanning path spacing of 10-40 μm, and a laser scanning milling machining accuracy requirement of ±5 μm. Step (2) Laser polishing is performed on the damaged area of ​​the aluminum alloy part after the removal of the hard anodized layer using laser scanning to achieve the required surface roughness; The laser scanning process parameters in step (2) include a laser wavelength of 1030-1070nm, a laser pulse width of 500fs-15ps, a laser repetition frequency of 500kHz-1MHz, a laser average power of 5-10W, a spot diameter of 20-50μm, a beam scanning speed of 1000mm / s-2000mm / s, a laser adjacent scanning path spacing of 2-10μm, and a roughness requirement of no more than 0.5μm after laser scanning polishing. The laser scanning methods in steps (1) and (2) include parallel line laser scanning, cross grid laser scanning, and intersecting line laser scanning; Step (3) Place the damaged area of ​​the aluminum alloy part after removing the hard anodized layer in the electrolyte to form an aluminum oxide film through electrolysis; Step (4) Dimensionally measure the prepared coating, requiring the coating thickness to be greater than the original coating thickness; Step (5) uses the same laser scanning method as step (1) to remove the coating processing allowance in step (4); Step (6) uses the same laser scanning method as in step (2) to polish the coating of the aluminum alloy parts after removing the coating machining allowance to the required surface roughness.

2. The laser repair method for localized scratches on the hard anodized layer of aluminum alloy parts according to claim 1, characterized in that: The machining allowance thickness range in step (4) is 50-200μm.

3. The laser repair method for localized scratches on the hard anodized layer of aluminum alloy parts according to claim 1, characterized in that: The machining accuracy and roughness in step (6) are the same as those in steps (1) and (2).

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