CN110666356A - Method for texturing surface of laser-etched aluminum alloy - Google Patents

Abstract

The invention provides a method for laser etching aluminum alloy surface texturing, which belongs to the technical field of aircraft aluminum alloy skin processing. Different texture surfaces are etched on the surface of the skin. The scanning speed is 2000mm/s, the frequency is 90kHz, the pulse width is 0.35μs, the number of scans is 1, the spacing is 0.3mm, the spot diameter is 50μm, and the power is 24W. By changing the scanning path of the laser, the aluminum alloy surface is etched with a textured structure to increase the surface roughness and surface wettability of the aluminum alloy skin, thereby increasing the adhesion of the aluminum alloy surface coating.

Description

A kind of method of laser etching aluminum alloy surface texturing

technical field

The invention relates to the technical field of aircraft aluminum alloy skin processing, in particular to a method for texturing the surface of an aluminum alloy by laser etching.

Background technique

In order to improve the weather resistance, chemical resistance and corrosion resistance of aircraft aluminum alloy skins, it is necessary to spray special aviation coatings on the surface of aircraft aluminum alloy skins. Improving the adhesion of aluminum alloy skin surface coatings has always been a research hotspot in the field of civil aviation. one. The development of new coatings is not only expensive, but also takes a long time. In order to increase the adhesion of coatings, surface modification of aluminum alloy skins has become a cost-effective method.

The chemical method for the surface treatment of aluminum alloy needs to go through the process of degreasing, pickling, cleaning, etc., but the waste liquid produced by the chemical method has great pollution to the environment. The chemical method increases the adhesion, produces waste liquid and pollutes the environment, and manual grinding requires higher proficiency of the staff and affects the health of the staff.

Application Publication No. CN109719469A discloses a textured surface processing method for improving the wear resistance of titanium alloys, comprising the following steps: using a honing machine to physically grind the surface of a titanium alloy substrate; The alloy substrate is cleaned and dried; the surface of the titanium alloy substrate is processed by a laser marking machine according to the processing plan; the surface of the processed titanium alloy substrate is polished by the method of fine polishing; The polished titanium alloy substrate is cleaned and dried in a cleaning machine. The patent obtains a variety of titanium alloy substrate surfaces with different surface properties by controlling the processing parameters of the laser technology. The local hardness, roughness and local elastic modulus of the titanium alloy substrate surface are different. It is used as friction for industrial equipment. It can obtain a lower coefficient of friction, show better anti-wear performance, and can carry a higher working load.

Application Publication No. CN109514174A discloses a laser texturing and anodizing surface treatment comprising the steps of: providing an article with a metallic surface; texturing the surface using a laser to create a controlled pattern across the surface; and The surface is anodized. The controlled pattern may comprise a series of pits etched in a predetermined repeating pattern (eg, an array or grid of dots) across the surface. The controlled pattern may also include a series of pits etched in a predetermined pseudo-random pattern across the surface. Its use is for polishing metal surfaces.

There are no reports on increasing the adhesion of aluminum alloy surface coatings by etching textured structures with lasers.

SUMMARY OF THE INVENTION

When the above-mentioned existing coating is to improve the adhesion of the aluminum alloy skin surface coating, the research and development of new coatings is expensive and the cycle is long; the waste liquid generated by the chemical method on the surface of the aluminum alloy has the defect of great pollution to the environment, and the method of the present invention is The purpose is to provide a method for laser etching aluminum alloy surface texture, by changing the scanning path of the laser to etch the texture structure on the aluminum alloy surface, to increase the surface roughness and surface wettability of the aluminum alloy skin, so as to increase the surface roughness and surface wettability of the aluminum alloy skin. Increase the adhesion of aluminum alloy surface coatings.

A method for laser etching aluminum alloy surface texturing, the method comprises using a galvanometer in a laser processing device to control a laser scanning path, etching different textured surfaces on the surface of aircraft aluminum alloy skin, and the scanning speed is 2000mm/ s, frequency 90kHz, pulse width 0.35μs, scan times 1, spacing 0.3mm, spot diameter 50μm, power 24W.

In the technical solution of the present application, the scanning path of the laser is controlled by a galvanometer, the scanning speed is 2000mm/s, the frequency is 90kHz, the pulse width is 0.35μs, the number of scans is 1, the spacing is 0.3mm, the spot diameter is 50μm, and the power is 24W. The surface of the skin is etched with different textured surfaces. By changing the scanning path of the laser, the surface of the aluminum alloy is etched with a textured structure to increase the surface roughness and surface wettability of the aluminum alloy skin, so as to increase the surface coating of the aluminum alloy. layer adhesion.

Preferably, the diameter of the pits produced by the laser on the surface of the aircraft aluminum alloy skin is 45-55 μm, the shape of the pits is approximately circular, and the pits are superimposed to form a scanning path.

More preferably, the diameter of the pit is 50 μm. The depth of the pit can be adjusted by adjusting the power of the laser; the path is formed by the superposition of pits, and the overlap ratio of the spot can be changed by controlling the pulse frequency and scanning speed, thereby affecting the surface roughness.

Preferably, the textured surface is diamond-shaped. Rhombus has the best roughness and wettability and is most beneficial to increase the adhesion of the coating.

Preferably, the textured surface is square. Surface texturing was performed using a pulsed laser device with a wavelength of 1064 nm, and the scanning path was a straight line formed by the superposition of light spots. The surface of the aircraft aluminum alloy skin is processed according to the preset scanning path, so that the aluminum alloy surface forms a square staggered line and a square texture structure to increase the surface roughness and surface wettability of the aluminum alloy skin, thereby increasing the aluminum alloy. Adhesion of surface coatings.

Preferably, the laser processing device includes a stage, a laser processing head is arranged above the stage, the laser processing head is electrically connected to a computer server, the computer server is also electrically connected to a laser, and the laser The laser beam is emitted into the input end of the laser processing head, and the laser processing head irradiates the laser beam downward on the surface of the aircraft aluminum alloy skin on the upper part of the stage, and the laser processing head is controlled by a six-axis mechanical arm . The graphics that need to be treated on the surface of the aircraft's aluminum alloy skin are input into the computer server in advance, the galvanometer is used to adjust the scanning path, the spot size is controlled by changing the field lens and the power is adjusted, and the overlap rate of the spot can be changed by controlling the pulse frequency and scanning speed. , The power of the laser can be adjusted through the computer server, and the dynamic laser processing head controlled by the six-axis robotic arm can be adjusted in a suitable position on the sample to be processed. The computer server controls the laser to emit light at the part that needs to be etched to complete the etching.

More preferably, the lower part of the six-axis robotic arm is provided with a fixed support.

More preferably, the laser processing head is provided with a galvanometer for adjusting the scanning path of the laser beam.

More preferably, the laser processing head is also provided with a distance sensor for realizing automatic focusing. The distance sensor enables autofocus.

Preferably, the laser is a pulsed laser with a wavelength of 1064 nm and an average power of 120W.

In the technical solution of this application:

The distance between each scanned parallel line is 300 μm;

The laser is 120W infrared fiber laser;

After the texturing of the present application, it can be directly sprayed without any treatment.

Compared with the prior art, the beneficial effects of the present invention are:

(1) By changing the scanning path of the laser, the surface of the aluminum alloy is etched with a texture structure to increase the surface roughness and surface wettability of the aluminum alloy skin, thereby increasing the adhesion of the aluminum alloy surface coating;

(2) The depth of the pit can be adjusted by adjusting the power of the laser; the path is formed by superimposing the pit, and the overlap rate of the spot can be changed by controlling the pulse frequency and the scanning speed, thereby affecting the surface roughness;

(3) The surface texture treatment is carried out by using a pulsed laser device with a wavelength of 1064 nm, and the scanning path is a straight line formed by the superposition of the light spots. The surface of the aluminum alloy is processed according to the preset scanning path, so that the surface of the aluminum alloy forms square staggered lines and a square texture structure to increase the surface roughness and surface wettability of the aluminum alloy skin, thereby increasing the surface coating of the aluminum alloy adhesion;

(4) The roughness and wettability of the diamond shape are the best, which is most beneficial to increase the adhesion of the coating;

(5) The existing laser technology is generally used to treat the aluminum alloy surface as much as possible. Such treatment will cause excessive roughness, and the coating cannot penetrate into the grooves etched by the laser, affecting the coating. adhesion. Compared with the prior art, the texture treatment of the aluminum alloy surface can select the corresponding pattern according to the viscosity of the paint, and the roughness of the aluminum alloy skin surface can be changed by controlling the scanning distance, changing the field lens, etc. The bonding force between the coating and the substrate is maximized;

(6) Input the graphics that need to be processed on the surface of the aircraft aluminum alloy skin into the computer server in advance, adjust the scanning path by the galvanometer, control the spot size by changing the field lens and adjusting the power, and change the spot size by controlling the pulse frequency and scanning speed. Lap rate, the power of the laser can be adjusted through the computer server, and the dynamic laser processing head controlled by the six-axis robotic arm can be adjusted in a suitable position on the sample to be processed, and the computer server controls the laser to emit light at the part that needs to be etched. etching.

Description of drawings

1 is a schematic structural diagram of a laser processing device of the present application;

Fig. 2 is the texture surface structure schematic diagram of the rhombus of the present application;

Fig. 3 is the texture surface structure schematic diagram of the square of the present application;

Fig. 4 is the original surface three-dimensional profile diagram of the aircraft aluminum alloy skin surface of the present application;

Fig. 5 is the three-dimensional profile diagram of the rhombus after the surface treatment of the aircraft aluminum alloy skin of the present application;

FIG. 6 is a three-dimensional outline view of a square after surface treatment of the aircraft aluminum alloy skin of the present application.

Reference numerals: 1-laser, 2-six-axis robotic arm, 3-laser processing head, 4-sample to be processed, 5-stage, 6-fixed support, 7-computer server.

Detailed ways

In order to make those skilled in the art better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to specific embodiments.

Example 1

As shown in Figure 1 and Figure 2, a method for laser etching aluminum alloy surface texturing, the method includes using a galvanometer in a laser processing device to control the scanning path of the laser, and etching the surface of the aircraft aluminum alloy skin. For different textured surfaces, the scanning speed is 2000mm/s, the frequency is 90kHz, the pulse width is 0.35μs, the number of scans is 1, the spacing is 0.3mm, the spot diameter is 50μm, and the power is 24W; the diameter of the pits generated by the laser on the surface of the aircraft aluminum alloy skin is 50μm , the shape of the pits is approximately circular, the pits are superimposed to form a scanning path, and the textured surface is rhombus.

Example 2

As shown in Figures 1 and 3, the diameter of the pit is 45 μm, the textured surface is square, and the rest are the same as in Example 1.

Example 3

As shown in Figures 1 and 2, the diameter of the pit is 50 μm, the textured surface is rhombus, and the rest are the same as in Example 1.

Example 4

As shown in FIG. 1 , the laser processing device includes a stage 5 , a laser processing head 3 is arranged above the stage 5 , and the laser processing head 3 is electrically connected to a computer server 7 , and the computer server 7 Also electrically connected with the laser 1, the laser 1 emits a laser beam into the input end of the laser processing head 3, and the laser processing head 3 irradiates the laser beam downward on the aircraft aluminum alloy mask on the upper part of the stage 5. The laser processing head 3 is controlled by the six-axis mechanical arm 2; the lower part of the six-axis mechanical arm 2 is provided with a fixed support 6; the laser processing head 3 is provided with a vibrator for adjusting the scanning path of the laser beam The laser processing head 3 is also provided with a distance sensor for realizing automatic focusing; the laser 1 is a pulsed laser 1 with a wavelength of 1064 nm and an average power of 120W.

Example 5

The surface of the rhombus or square aircraft aluminum alloy skin obtained in Example 1-4 was briefly wiped with anhydrous ethanol to remove surface debris, and Xuanwei RECOATABLE EPOXY 300 type epoxy two-component aviation special paint was used, and sprayed evenly. Spray on the surface of the sample, the thickness of the coating is controlled at 40-50μm, the temperature of the painting environment is controlled at 20-24°C, preferably 22°C, and the relative humidity is controlled at 53-57%, preferably 55%, using Sata SATAjet H type Spray gun, spraying air pressure 50MPa, QJT-2.3M paint mist purification device is used in the spraying process, which conforms to the technical indicators of paint construction and the national standard GB 14444-93 "Safety Technical Regulations for Spray Paint Room". It was placed at room temperature for 7 days, and after the coating was dry, the adhesion was tested using the American DeFelsko PosiTest AT-A pull-off adhesion tester. According to the requirements of GB/T 5210-2006 "Paints and Varnishes Adhesion Test by Pull-Off Method", the samples should be placed for at least 16 hours at a temperature of 23 °C and a relative humidity of 50% before the test. The layers are closely combined, and each sample is tested for 6 groups, and the obtained values are averaged, as shown in Table 1.

Table 1 Coating adhesion of samples with different treatments

The adhesion of the original sample is 6.71MPa, and the adhesion between the square sample and the diamond sample is about 70% higher than that of the original sample.

Test Example 1

As shown in Figures 4, 5 and 6, the surface roughness was measured using a laser scanning confocal microscope (LSCM) of Olympus OLS4100, Germany, with a 5x objective lens, where the roughness of the original surface was 1.9 μm, and a diamond-shaped laser The treated surface roughness reaches 7.9 μm, and the roughness is significantly improved.

Test Example 2

As shown in Figures 4, 5 and 6, the contact angle of the sample surface was measured by using the DSA100 video contact angle measuring instrument from KRUSS, Germany. Using distilled water as the test liquid, the contact angle of the original surface was 53.8°. The size of the surface contact angle is 25.6°, and it can be seen that the surface of the sample after laser treatment has better wettability.

Test Example 3

As shown in Figures 4, 5 and 6, the adhesion of the surface coating was tested by the American DeFelsko PosiTest AT-A pull-off adhesion tester. The adhesion of the sample was tested after spraying, and the adhesion of the original sample was 6.71. MPa, the coating adhesion of the laser-treated sample is 11.53MPa, and it can be seen that the laser surface texturing treatment can effectively improve the coating adhesion.

In this application, the scale (1-500 μm) in Figures 2 and 3 shows an enlarged scale.

The above-mentioned embodiments only represent specific implementations of the present application, and the descriptions thereof are specific and detailed, but should not be construed as limiting the protection scope of the present application. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the technical solution of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application.

Claims (10)

1. a method for laser etching aluminum alloy surface texturing, it is characterized in that, described method comprises the scanning path that adopts the galvanometer in the laser processing device to control the laser, etch different textures on the aircraft aluminum alloy skin surface Surface, scanning speed 2000mm/s, frequency 90kHz, pulse width 0.35μs, scanning times 1 time, spacing 0.3mm, spot diameter 50μm, power 24W. 2. a method for laser etching aluminum alloy surface texturing according to claim 1, is characterized in that, the diameter of the pit that laser produces on the surface of the aircraft aluminum alloy skin is 45-55 μm, and the shape of the pit is approximately a circle. shape, the pits are superimposed to form a scanning path. 3. The method for texturing the surface of an aluminum alloy by laser etching according to claim 2, wherein the diameter of the pit is 50 μm. 4. The method for texturing the surface of an aluminum alloy by laser etching according to claim 1, wherein the textured surface is a rhombus. 5. The method for texturing the surface of an aluminum alloy by laser etching according to claim 1, wherein the textured surface is a square. 6. A method for laser etching aluminum alloy surface texturing according to claim 1, wherein the laser processing device comprises a stage, and a laser processing head is arranged above the stage, and the The laser processing head is electrically connected to a computer server, and the computer server is also electrically connected to a laser, the laser emits a laser beam into the input end of the laser processing head, and the laser processing head irradiates the laser beam downward on the carrier. The aircraft aluminum alloy skin surface on the upper part of the stage, the laser processing head is controlled by a six-axis robotic arm. 7 . The method for texturing the surface of an aluminum alloy by laser etching according to claim 5 , wherein the lower part of the six-axis robotic arm is provided with a fixed support. 8 . 8 . The method for texturing the surface of an aluminum alloy by laser etching according to claim 5 , wherein the laser processing head is provided with a galvanometer for adjusting the scanning path of the laser beam. 9 . 9 . The method for texturing the surface of an aluminum alloy by laser etching according to claim 8 , wherein the laser processing head is further provided with a distance sensor for realizing automatic focusing. 10 . 10. The method for laser etching aluminum alloy surface texturing according to claim 5, wherein the laser is a pulsed laser with a wavelength of 1064 nm and an average power of 120W.

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