A multi-modality laser processing system and method

Abstract

The application provides a multi-system laser processing system and a processing method, the multi-system laser processing system is composed of a digital pulse delay device, an auxiliary displacement platform, an ultraviolet picosecond laser, an infrared nanosecond laser, a first energy meter, a second energy meter, a first test total reflection mirror, a second test total reflection mirror, a total reflection mirror, a polarizer, a beam adjusting device, an auxiliary laser light source, a beam expander, the auxiliary displacement platform, a high-speed camera, an automatic zoom three-dimensional surface measuring instrument, a general control platform and a flue gas purification device.The application also provides a method for multi-system laser processing by using the system.The multi-system laser processing system and the processing method provided by the application can solve the problems of poor effect, low efficiency and poor activation effect when a single pulse width laser is used for surface treatment of a composite material.

Description

Technical Field

[0001] This invention belongs to the field of composite material processing, and specifically relates to a multi-mode laser processing system and method for performing multi-mode laser surface treatment on carbon fiber composite materials with multiple pulse widths and multiple wavelengths. Background Technology

[0002] Carbon fiber reinforced polymer / plastic (CFRP) is a composite material with resin as the matrix and carbon fiber as the reinforcement. Compared with traditional metal materials, carbon fiber reinforced resin matrix composites have a series of excellent properties such as high specific strength, high specific modulus, corrosion resistance, fatigue resistance, and good electrical conductivity. They are widely used as lightweight materials in aerospace, automotive, wind power, construction, sporting goods, civil engineering and other fields.

[0003] CFRP has many advantages, but it also has disadvantages such as low compressive strength and poor low-temperature resistance. In most applications, CFRP needs to be combined with composite materials or metals to construct a complete structure. Traditional mechanical connections (such as riveting and bolting) between CFRP and other materials not only reduce the static strength of the joint but also increase the load on the materials. Therefore, adhesive bonding, as a new method, can distribute the force across the entire joint surface, thereby reducing stress concentration and improving the durability and load-bearing capacity of the connection. Secondly, adhesive bonding can form a uniform distribution on the joint surface, improving the accuracy of the joint surface and reducing corrosion, thus improving the quality of the connection. Adhesive bonding is simple to operate and can distribute the force across the entire joint surface, thereby reducing stress concentration and improving the durability and load-bearing capacity of the connection.

[0004] CFRP (Chemical Fluorescent Reinforced Polymer) has a surface coated with a highly crystalline polymer resin, which is typically hydrophobic, making it difficult for adhesives to adhere and form a strong bond. Therefore, before painting or bonding, the CFRP surface needs to be pretreated to remove various contaminants and increase surface energy, making it more conducive to adhesion and thus improving quality and reliability. Currently, chemical treatment, mechanical polishing, and plasma treatment are commonly used to surface treat CFRP and metals to remove residual impurities, increase activation energy, and increase surface roughness. However, these methods have drawbacks such as significant pollution, low efficiency, and uneven surface treatment. Laser bonding technology is a rapidly developing bonding technology in recent years. Due to its low heat input, high precision, simple operation, and high efficiency, it can enhance the surface roughness and surface activity of CFRP, making it very suitable for treating composite material surfaces, filling the gaps in traditional treatment technologies, and showing great application prospects.

[0005] However, the vastly different physical properties of fibers and resins, including their mechanical, thermal, and optical properties, mean that while the surface treatment effect is excellent when lasers act on both fibers and the matrix simultaneously, the resin is often difficult to remove uniformly at the microscale, leading to processing damage and limited processing precision. As industrialization increases, various industries have more stringent requirements for laser processing. For example, in CFRP surface treatment, resins and fibers have different absorption rates for laser energy and wavelength. Laser wavelengths with lower absorption rates are limited during processing, resulting in poor treatment effects, low efficiency, and significant damage to the CFRP, leading to a substantial reduction in mechanical properties.

[0006] Existing CFRP laser surface pretreatment methods are mainly distinguished in two aspects:

[0007] First, based on the laser output mode (laser pulse width), lasers can be categorized into continuous pulse lasers, long-pulse lasers (microseconds, milliseconds), short-pulse lasers (nanoseconds), and ultrafast lasers (picoseconds, femtoseconds). Laser processing can also be classified into thermodynamic and non-thermodynamic processes based on pulse width. When the pulse width is higher than 10... -11 When the laser is applied to CFRP, the melting, vaporization, and removal of the material during burning are all achieved through thermal effects. While highly efficient, this process can easily cause severe thermal impact and damage to the edges of the laser-burned area. However, when a picosecond laser is applied to CFRP, the laser pulse duration is shorter than the electron-lattice energy relaxation time (10⁻⁶ Hz). -11 -10 -12 In the pulse duration, the movement of the lattice and thermal conduction are negligible. The material undergoes an instantaneous non-thermal phase transition. The laser energy is ejected with the formed plasma before it can diffuse to the surrounding area, thus avoiding the thermal effects and damage caused by thermal diffusion. This results in neat and high-precision processing. The disadvantages are long pre-processing time and low efficiency.

[0008] Secondly, based on the laser wavelength used, pretreatment can be divided into ultraviolet laser pretreatment, near-infrared laser pretreatment, and mid-infrared laser pretreatment. Ultraviolet laser pretreatment uses laser wavelengths between 100 and 400 nm, with relatively high single-photon energy. This single-photon energy is sufficient to break the chemical bonds of organic molecules, causing photochemical decomposition of the surface resin matrix, thereby removing the resin matrix and contaminants from the material surface. The advantages of this method are strong controllability of resin removal thickness and minimal damage to internal fibers; the disadvantages are long pretreatment time and low efficiency.

[0009] Therefore, developing a technology that can overcome the shortcomings of existing CFRP laser surface pretreatment methods has become an urgent problem to be solved. Summary of the Invention

[0010] To address the aforementioned problems, the present invention aims to provide a multi-mode laser processing system. This system utilizes multi-pulse-width, multi-wavelength laser thermo-mechanical coupling to enhance the processing of composite materials, thereby resolving the issues of poor performance, low efficiency, and poor activation effect when using single-pulse-width lasers to treat the surface of composite materials.

[0011] Another object of the present invention is to provide a multi-mode laser processing method.

[0012] To achieve the above objectives, the present invention provides a multi-mode laser processing system, comprising an ultraviolet picosecond laser, an infrared nanosecond laser, a first test total reflection mirror, a second test total reflection mirror, a first energy meter, a second energy meter, a digital pulse delay unit, a total reflection mirror, a polarizer, a beam adjustment device, an auxiliary laser source, a beam expander, a central control platform, a high-speed camera, an auxiliary displacement platform, an automatic zoom three-dimensional surface measuring instrument, and a flue gas purification device;

[0013] The first energy meter has a first probe, and the second energy meter has a second probe.

[0014] The digital pulse delay unit is connected to the ultraviolet picosecond laser and the infrared nanosecond laser, respectively.

[0015] The first test total reflection mirror is detachably installed in the laser light path emitted by the ultraviolet picosecond laser, and the mirror surface of the first test total reflection mirror is tilted at 45° towards the ultraviolet picosecond laser; the first probe of the first energy meter is installed in the light path of the laser emitted by the ultraviolet picosecond laser reflected by the first test total reflection mirror, so that the first probe receives the energy signal of the laser emitted by the ultraviolet picosecond laser;

[0016] The total reflection mirror is placed behind the first test total reflection mirror in the laser beam path emitted by the ultraviolet picosecond laser, and the mirror surface of the total reflection mirror is tilted at 45° towards the ultraviolet picosecond laser.

[0017] The second total reflection mirror is detachably installed in the laser beam path emitted by the infrared nanosecond laser, and the mirror surface of the second total reflection mirror is tilted at 45° towards the infrared nanosecond laser; the second probe of the second energy meter is installed in the laser beam path reflected by the second total reflection mirror emitted by the infrared nanosecond laser, so that the second probe receives the energy signal of the laser emitted by the infrared nanosecond laser.

[0018] A polarizer is placed behind the second total reflection mirror in the laser beam path emitted by the infrared nanosecond laser. The mirror surface of the polarizer is tilted at 45° and the polarizer is also located in the light path of the laser emitted by the ultraviolet picosecond laser after being reflected by the total reflection mirror.

[0019] The mirror surface of the polarizer is parallel to the total reflection mirror, so that the laser emitted by the ultraviolet picosecond laser and the laser emitted by the infrared nanosecond laser can be combined into a single laser beam through the polarizer.

[0020] The beam adjustment device and the auxiliary displacement platform are sequentially arranged in the optical path of the combined laser beam; the beam adjustment device includes a scanning galvanometer and a field mirror located in the optical path of the combined laser beam; the auxiliary displacement platform is used to fix the target material, and the target material receives the irradiation of the combined laser beam after passing through the field mirror.

[0021] The auxiliary laser source is located on one side of the optical path of the combined laser. The laser emitted by the auxiliary laser source is expanded by the beam expander and then received by the high-speed camera on the other side of the optical path of the combined laser.

[0022] The high-speed camera is connected to the central control platform; the central control platform is also connected to the beam adjustment device;

[0023] The auxiliary displacement platform is used to fix the flue gas purification device on one side of the target material;

[0024] The auxiliary displacement platform is wirelessly connected to the automatic zoom three-dimensional surface measuring instrument, which in turn is wirelessly connected to the central control platform.

[0025] As described above, the output power of the infrared nanosecond laser is 10-50W, the frequency of the infrared laser emitted by the infrared nanosecond laser is 200-1000kHz, and the spot diameter is 20-50μm.

[0026] As described above, the output power of the ultraviolet picosecond laser is 5-10W, the frequency of the ultraviolet laser emitted by the ultraviolet picosecond laser is 200-1000kHz, and the spot diameter is 20-50μm.

[0027] As mentioned above, the central control platform is a computer, mobile phone, or tablet computer.

[0028] The present invention also provides a method for performing multi-mode laser processing using the above-described system, comprising the following steps:

[0029] 1) Perform ultrasonic cleaning on the surface of the target material, and then fix the target material to be treated on the auxiliary displacement platform;

[0030] 2) Adjust the working position of the ultraviolet picosecond laser, turn on the laser indicator light of the ultraviolet picosecond laser, so that the laser emitted by the ultraviolet picosecond laser illuminates the first test total reflection mirror and reflects it to the first detector head, and the laser signal is collected by the first energy meter to measure the laser power;

[0031] 3) Adjust the working position of the infrared nanosecond laser, turn on the laser indicator light of the infrared nanosecond laser, so that the laser emitted by the infrared nanosecond laser illuminates the second test total reflection mirror and reflects it to the second detector head, and the laser signal is collected by the second energy meter to measure the laser power;

[0032] 4) Disassemble the first test total reflection mirror and the second test total reflection mirror so that the laser emitted by the ultraviolet picosecond laser is reflected by the total reflection mirror to the polarizer, and the laser emitted by the infrared nanosecond laser is integrated with the laser beam at the polarizer.

[0033] 5) The integrated beam is passed through the scanning galvanometer and field mirror in the beam adjustment device to output indicator light that irradiates the target surface. The beam adjustment device is controlled and adjusted by the central control platform to ensure accurate focusing of the optical path and maximize the brightness of the spot acting on the target. Then, the beam and beam adjustment device are observed for polarization or light leakage. After ensuring that there is no polarization or light leakage, the ultraviolet picosecond laser and the infrared nanosecond laser are turned off, completing the preparation work.

[0034] 6) Turn on the picosecond laser, nanosecond laser, auxiliary laser source, and high-speed camera, and then start the digital pulse delay unit;

[0035] 7) Set the pulse delay of the digital pulse delayer to 1ms; set the parameters of the infrared nanosecond laser to: laser output wavelength 1064nm, pulse width 10~500ns, repetition rate 100~2500kHz, output power 1~100W; set the parameters of the ultraviolet picosecond laser to: laser output wavelength 355nm, pulse width 10ps, repetition rate 100~2000kHz, output power 1~30W; then use the digital pulse delayer to send signals to the ultraviolet picosecond laser and the infrared nanosecond laser, so that the ultraviolet picosecond laser outputs picosecond laser and the infrared nanosecond laser outputs nanosecond laser;

[0036] 8) The picosecond laser output from the ultraviolet picosecond laser passes through a total reflection mirror and a polarizer, while the nanosecond laser output from the infrared nanosecond laser passes through a polarizer to achieve laser beam combining.

[0037] 9) The combined laser beam passes through a beam adjustment device containing a scanning galvanometer and a field mirror to complete the adjustment of the combined laser beam;

[0038] 10) The adjusted and combined laser beam irradiates the target surface for processing and marking; at the same time, a fume purification system is used to absorb the fumes and mist generated during processing and marking; the beam adjustment device is adjusted using the central control platform; the target position is adjusted using an auxiliary displacement platform; simultaneously, a high-speed camera is used to observe the plasma impact phenomenon generated by the laser beam under the thermal coupling of the combined laser beam; the depth, roughness, and surface morphology of the target surface are observed and data are collected using an automatic zoom three-dimensional surface measuring instrument, and the data are input into the central control platform for analysis;

[0039] 11) Further feedback adjustment based on the analysis results of the central control platform: Repeat steps 7) to 10) in order to achieve the best treatment effect and the highest treatment efficiency on the target surface.

[0040] As described above, the pulse width in the infrared nanosecond laser parameters in step 7) is 10 ns or 60 ns.

[0041] As described above, the vertical height difference between the field lens and the target surface is 140-190 mm.

[0042] This invention addresses the shortcomings of current laser surface treatment technologies for composite materials by proposing a multi-mode laser-thermal coupling synergistic method for treating material surfaces, which has the following characteristics:

[0043] I. Achieving more efficient surface treatment: By integrating the beams of an infrared nanosecond laser with a wavelength of 1064nm and an ultraviolet picosecond laser with a wavelength of 355nm, the combined laser irradiates the surface of the composite material, causing the material on the surface of the composite material to melt or vaporize, achieving a highly efficient treatment effect, improving the laser processing efficiency, and being suitable for processing a variety of materials.

[0044] Second, to achieve high surface performance, a 1064nm nanosecond laser first removes the resin on the composite material to roughen the surface. Then, a picosecond laser high-energy laser pulse melts, vaporizes, and solidifies the material to form a surface microstructure, further improving surface quality and performance.

[0045] Third, the plasma generated by the laser activates the surface of the composite material, thereby activating chemical bonds on the surface, increasing surface roughness, and thus improving surface energy. This enhances the adhesion and wettability of the material, making it more suitable for surface coating and bonding applications. Compared with traditional single laser surface cleaning methods, this treatment method is more efficient, thereby improving surface quality and performance.

[0046] The beneficial effects of this invention are as follows:

[0047] This invention provides a multi-mode laser processing system and method, which utilizes multi-pulse thermally coupled lasers for surface treatment. The 1064nm nanosecond laser and the 355nm picosecond laser are integrated and combined to enhance the absorption of surface materials and achieve more comprehensive and rapid thermal accumulation, thereby rapidly melting or vaporizing the surface materials of composite materials, achieving a highly efficient processing effect and improving the efficiency of laser processing. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the laser surface treatment process provided in an embodiment of the present invention.

[0049] Figure 2 This is a topographic image of the CFRP surface after infrared nanosecond laser treatment.

[0050] Figure 3 This is a morphology image of the CFRP surface after UV picosecond laser treatment.

[0051] Figure 4 The image shows the morphology of CFRP surface after multi-mode laser treatment.

[0052] Figure 5 The image shows the morphology of CFRP surface after multi-mode laser treatment.

[0053] Figure 6 The three-dimensional morphology of CFRP after multi-mode laser processing.

[0054] Figure Labels

[0055] 1: Ultraviolet picosecond laser; 2: Infrared nanosecond laser; 3: First test total reflection mirror; 4: Second test total reflection mirror; 5: First energy meter; 51: First probe head; 6: Second energy meter; 7: Digital pulse delay unit; 8: Total reflection mirror; 9: Polarizer; 10: Scanning galvanometer; 11: Field lens; 12: Target material; 13: Auxiliary laser source; 14: Beam expander; 15: Central control platform; 16: High-speed camera; 17: Auxiliary displacement platform; 18: Automatic zoom three-dimensional surface measuring instrument; 19: Flue gas purification device. Detailed Implementation

[0056] The embodiments of the present invention will now be described in detail and comprehensively so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0057] Single-mode laser surface treatment phenomenon: Different wavelengths of laser have different effects on carbon fiber composites. When the wavelength is greater than 1000nm, the absorption rate of the composite material to the laser is low, and the laser penetrates the surface of the resin layer and acts downward, resulting in a large damage depth to the composite material. The main damage mode is resin decomposition, which will cause damage to the resin inside the composite material. When the wavelength is less than 400nm, the laser treatment process for CFRP is a photochemical process, and the composite material has a high absorption rate of this laser wavelength. The damage depth of the composite material is small and will not cause damage to the resin inside the composite material. However, due to the short wavelength, the resin or dirt on the material surface may not be completely removed.

[0058] Lasers with different pulse widths have different effects on the processing of carbon fiber composite materials. When the pulse width is higher than 10- 11 At pulse widths of 10⁻⁶ seconds (nanosecond lasers), the primary effect is thermal, causing severe thermal damage to the laser-burned area. 11 At picosecond laser pulse widths (s), the material undergoes an instantaneous non-thermal phase transition, thus avoiding the thermal effects and damage caused by thermal diffusion. Therefore, the overall efficiency of laser treatment of CFRP surfaces decreases as the laser pulse width decreases, while the damage increases as the laser pulse width increases.

[0059] When a single laser is used to treat the surface of CFRP, the resin absorbs the heat energy input by the laser on the CFRP surface, causing oxidation, decomposition, and vaporization, producing dense white smoke. When a single infrared nanosecond laser is used to treat the CFRP surface, if the laser output power is low (laser power 20W, repetition frequency 500kHz, pulse width 60ns, number of scans 3, spot diameter 22μm), the laser energy is absorbed by surface impurities and resin. However, the low laser power density can only remove part of the resin, exposing the complete carbon fibers. It cannot completely remove the resin or contaminants on the surface of the resin-based composite material, thus the surface resin cannot be completely removed. Figure 2 As shown in Figure A; if the laser output power is too high (laser power 80W, repetition frequency 500kHz, pulse width 60ns, number of scans 3, spot diameter 22μm), it can be seen that under these parameters, the resin on the CFRP surface is completely removed, but some carbon fibers are burned off. When the output laser power is too high, the output energy not only vaporizes and decomposes the impurities and resin, but the excessive heat also burns off the carbon fibers, such as... Figure 2 As shown in B.

[0060] When using a single ultraviolet picosecond laser to treat the CFRP surface, the heating and melting process of CFRP is brief, primarily influenced by photophysical and photochemical effects. Photophysical effects include the generation of high-intensity electromagnetic fields and localized plasmas through nonlinear optical effects, enabling efficient removal of impurities, contaminants, and resin from the CFRP surface. Photochemical reactions occur under ultraviolet light irradiation, causing the chemical bonds on the CFRP surface to break or recombine, thus modifying and altering the surface. Therefore, thermal damage is minimal during CFRP treatment with an ultraviolet picosecond laser. At lower laser power (10W, 500kHz repetition rate, 8 scans, 19μm spot diameter), resin residue remains, but the fibers are not damaged. Figure 4 (A). As the laser power gradually increased, after multiple scans (laser power 20W, repetition frequency 500kHz, number of scans 8, spot diameter 19μm), a large amount of resin in the center was removed, but resin residue remained around the edges, such as... Figure 4 (B). If the laser power and the number of scans are increased at this point, some fibers will be damaged.

[0061] equipment:

[0062] 1. The ultraviolet picosecond laser was purchased from Beijing Shenglai Technology Co., Ltd., product number: leonis-355-30.

[0063] 2. The infrared nanosecond laser was purchased from Shenzhen Gongda Laser Co., Ltd., product number: 100W MOPA pulsed fiber laser.

[0064] 3. The energy meter was purchased from Ophir, product number: 30A-BB-18.

[0065] 4. The digital pulse delay unit was purchased from STANFORD in the United States, product number: DG645.

[0066] 5. The scanning galvanometer in the beam adjustment device was purchased from Anshan Precision Optical Scanning Technology Co., Ltd., product number: RAY-MOTION; the field lens was purchased from Nanjing Wavelength Optoelectronic Technology Co., Ltd., product model: NJSL-427SL-355-110-160Q-D12.

[0067] 6. The auxiliary laser source was purchased from Changchun New Industries Optoelectronic Technology Co., Ltd.

[0068] 7. The central control platform is a computer paired with Golden Orange circuit boards and corresponding control software produced by Beijing Golden Orange Technology Co., Ltd.

[0069] 8. The high-speed camera was purchased from Photron, product number: FASTCAM SA-Z.

[0070] 9. The auxiliary displacement platform was purchased from Beijing Fuliqintian Optoelectronic Technology Co., Ltd.

[0071] 10. The automatic zoom 3D surface measuring instrument was purchased from Alicona GmbH, Austria, product number: InfiniteFocus G5.

[0072] 11. The flue gas purification device is a small desktop purifier purchased from Shenzhen Jiuyefeng Technology Co., Ltd.

[0073] Example 1

[0074] like Figure 1 The multi-mode laser processing system provided by the present invention shown consists of an ultraviolet picosecond laser 1, an infrared nanosecond laser 2, a first total reflection mirror 3, a second total reflection mirror 4, a first energy meter 5, a second energy meter 6, a digital pulse delay unit 7, a total reflection mirror 8, a polarizer 9, a beam adjustment device, an auxiliary laser source 13, a beam expander 14, a central control platform 15, a high-speed camera 16, an auxiliary displacement platform 17, an automatic zoom three-dimensional surface measuring instrument 18, and a flue gas purification device 19.

[0075] The first energy meter 5 has a first probe 51, and the second energy meter 6 has a second probe 61;

[0076] The digital pulse delay unit 7 is connected to the ultraviolet picosecond laser 1 and the infrared nanosecond laser 2, respectively.

[0077] The output power of an infrared nanosecond laser is 10-50W, the frequency of the infrared laser emitted by the infrared nanosecond laser is 200-1000kHz, and the spot diameter is 20-50μm.

[0078] The output power of the ultraviolet picosecond laser is 5-10W, the frequency of the ultraviolet laser emitted by the ultraviolet picosecond laser is 200-1000kHz, and the spot diameter is 20-50μm.

[0079] like Figure 1 In the multi-mode laser processing system shown, solid lines represent online processing, and dashed lines represent wireless connections. Compared to traditional laser processing methods, manually controlling the laser output is not only less precise but also unable to achieve effects such as laser delay. A digital pulse delay unit, as a high-precision output signal generator, can enable both the ultraviolet picosecond laser and the infrared nanosecond laser to simultaneously release their output signals, achieving synchronized output from both lasers.

[0080] The first total reflection mirror 3 is detachably installed in the laser light path emitted by the ultraviolet picosecond laser 1. The mirror surface of the first total reflection mirror 3 is tilted at 45° towards the ultraviolet picosecond laser 1. The first probe 51 of the first energy meter 5 is installed in the light path of the laser emitted by the ultraviolet picosecond laser 1 after being reflected by the first total reflection mirror 3, so that the first probe 51 receives the energy signal of the laser emitted by the ultraviolet picosecond laser 1.

[0081] To ensure the consistency and reproducibility of the laser processing process, an energy meter is usually installed behind the laser to measure the laser power in real time. This is because the laser output is easily affected by objective factors such as water molecules and floating objects in the air. These factors can cause diffuse reflection and absorption of the laser, resulting in the loss of some laser energy.

[0082] A total reflection mirror 8 is placed behind the first test total reflection mirror 3 in the laser beam path emitted by the ultraviolet picosecond laser 1. The mirror surface of the total reflection mirror 8 is tilted at 45° towards the ultraviolet picosecond laser 1.

[0083] The second total reflection mirror 4 is detachably mounted on the laser beam path emitted by the infrared nanosecond laser 2. The mirror surface of the second total reflection mirror 4 is tilted at 45° towards the infrared nanosecond laser 2. The second probe 61 of the second energy meter 6 is mounted on the laser beam path reflected by the second total reflection mirror 4, so that the second probe 61 receives the energy signal of the laser beam emitted by the infrared nanosecond laser 2.

[0084] A polarizer 9 is placed behind the second total reflection mirror 4 in the laser light path emitted by the infrared nanosecond laser 2. The mirror surface of the polarizer 9 is tilted at 45° and the polarizer 9 is also located in the light path of the laser emitted by the ultraviolet picosecond laser 1 after being reflected by the total reflection mirror 8.

[0085] A total reflection mirror is used to deflect the straight-propagating picosecond laser by 45 degrees, so that it is incident vertically downwards. Then, it is combined with the straight-propagating infrared nanosecond laser through a polarizer.

[0086] The mirror surface of the polarizer 9 is parallel to the total reflection mirror 8, so that the laser emitted by the ultraviolet picosecond laser 1 and the laser emitted by the infrared nanosecond laser 2 can be combined into a single laser beam through the polarizer 9.

[0087] The beam adjustment device and the auxiliary displacement platform 17 are sequentially arranged in the optical path of the combined laser beam; the beam adjustment device includes a scanning galvanometer 10 and a field mirror 11 located in the optical path of the combined laser beam.

[0088] The laser is adjusted by combining a scanning galvanometer and a field isolation structure, so that it moves along the X and Y vertical directions and processes the target material along a predetermined trajectory.

[0089] The auxiliary displacement platform 17 is used to fix the target 12, which receives the combined laser beam after passing through the field lens 11; the auxiliary displacement platform can move the target to achieve surface treatment of large targets.

[0090] When processing small target surfaces, the scanning galvanometer can directly achieve complete surface treatment, and the target position can be fine-tuned using an auxiliary displacement platform for more precise positioning. However, when processing large material surfaces, since the positions of the scanning galvanometer and the field lens are fixed, it is necessary to move the auxiliary displacement platform to ensure that the untreated portion remains below the field lens to guarantee the continuity of the treated area in order to process large surfaces.

[0091] The auxiliary laser source 13 is located on one side of the optical path of the combined laser beam. The laser beam emitted by the auxiliary laser source 13 is expanded by the beam expander 14 and then received by the high-speed camera 16 on the other side of the optical path of the combined laser beam. The auxiliary laser source outputs green light to assist the high-speed camera in capturing the processing process.

[0092] The high-speed camera 16 is connected to the central control platform 15; the central control platform 15 is also connected to the beam adjustment device;

[0093] The auxiliary displacement platform 17 is used to fix the flue gas purification device 19 on one side of the target material 12;

[0094] The auxiliary displacement platform 17 is wirelessly connected to the automatic zoom three-dimensional surface measuring instrument 18, and the automatic zoom three-dimensional surface measuring instrument 18 is wirelessly connected to the central control platform 15, which is a computer.

[0095] The specific processing procedure for the target material is as follows:

[0096] 1) Perform ultrasonic cleaning on the surface of the target material, and then fix the target material to be treated on the auxiliary displacement platform;

[0097] 2) Adjust the working position of the ultraviolet picosecond laser, turn on the laser indicator light of the ultraviolet picosecond laser, so that the laser emitted by the ultraviolet picosecond laser illuminates the first test total reflection mirror and reflects it to the first detector head, and the laser signal is collected by the first energy meter to measure the laser power;

[0098] 3) Adjust the working position of the infrared nanosecond laser, turn on the laser indicator light of the infrared nanosecond laser, so that the laser emitted by the infrared nanosecond laser illuminates the second test total reflection mirror and reflects it to the second detector head, and the laser signal is collected by the second energy meter to measure the laser power;

[0099] 4) Disassemble the first test total reflection mirror and the second test total reflection mirror so that the laser emitted by the ultraviolet picosecond laser is reflected by the total reflection mirror to the polarizer, and the laser emitted by the infrared nanosecond laser is integrated with the laser beam at the polarizer.

[0100] 5) The integrated beam is passed through the scanning galvanometer and field mirror in the beam adjustment device to output indicator light that irradiates the target surface. The beam adjustment device is controlled and adjusted by the central control platform to ensure accurate focusing of the optical path and maximize the brightness of the spot acting on the target. Then, the beam and beam adjustment device are observed for polarization or light leakage. After ensuring that there is no polarization or light leakage, the ultraviolet picosecond laser and the infrared nanosecond laser are turned off, completing the preparation work.

[0101] 6) Turn on the ultraviolet picosecond laser, the infrared nanosecond laser, the auxiliary laser source, and the high-speed camera, and then start the digital pulse delay unit;

[0102] 7) Set the pulse delay of the digital pulse delayer to 1ms; set the parameters of the infrared nanosecond laser as follows: laser output wavelength 1064nm, pulse width 10-500ns, repetition rate 100-2500kHz, output power 1-100W; set the parameters of the ultraviolet picosecond laser as follows: laser output wavelength 355nm, pulse width 10ps, repetition rate 100-2000kHz, output power 1-30W; then use the digital pulse delayer to send signals to the ultraviolet picosecond laser and the infrared nanosecond laser, so that the ultraviolet picosecond laser outputs picosecond laser and the infrared nanosecond laser outputs nanosecond laser; in this embodiment, the pulse width of the infrared nanosecond laser is 60ns. Adjust the vertical height difference between the scene and the target surface to 160mm.

[0103] 8) The picosecond laser output from the ultraviolet picosecond laser passes through a total reflection mirror and a polarizer, while the nanosecond laser output from the infrared nanosecond laser passes through a polarizer to achieve laser beam combining.

[0104] 9) The combined laser beam passes through a beam adjustment device containing a scanning galvanometer and a field mirror to complete the adjustment of the combined laser beam;

[0105] 10) The adjusted and combined laser beam irradiates the target surface for processing and marking; at the same time, a fume purification system is used to absorb the fumes and mist generated during processing and marking; the beam adjustment device is adjusted using the central control platform; the target position is adjusted using an auxiliary displacement platform; simultaneously, a high-speed camera is used to observe the plasma impact phenomenon generated by the laser beam under the thermal coupling of the combined laser beam; the target information is collected using an automatic zoom three-dimensional surface measuring instrument and input into the central control platform for analysis;

[0106] 11) Further feedback adjustment based on the analysis results of the central control platform: Repeat steps 7) to 10) in order to achieve the best treatment effect and the highest treatment efficiency on the target surface.

[0107] Due to phenomena such as smoke and plasma expansion, smoke may clog the laser beam, leading to a decrease in processing efficiency; plasma, an ionized gas generated by focusing laser energy on the workpiece surface, can cause high temperatures during processing. However, by observing these phenomena, the impact can be reduced by adjusting parameters such as laser focal length, power, and scanning speed.

[0108] As can be seen from the above embodiments, in the laser sequencing of the multi-mode lasers provided by this invention, infrared nanosecond lasers are selected for priority processing, followed by ultraviolet picosecond lasers, and the energy ratio and pulse delay are controlled. During the laser surface treatment process, through numerous single-factor experiments, experiments were first conducted on laser output power. It was found that regardless of the laser type, higher power meant more energy was delivered to the material surface, leading to more significant surface deformation or melting, which would cause fiber breakage and deformation. Therefore, low-power multi-pass scanning was performed, and the scanning speed and repetition frequency were adjusted to control the overlap rate of the laser spot, thereby reducing the overlap of laser energy. Subsequently, after controlling the delay of the two lasers, the optimal effect was finally obtained. The resin surface was relatively clean, with no resin recasting, and minimal fiber damage. Two processing schemes were given. Scheme 1 (scanning speed, repetition frequency, and number of scans are all the same, 1000mm / s, 1000kHz, 2 scans respectively, infrared nanosecond laser power 40W, ultraviolet picosecond laser power 5W) showed the following effect: Figure 5 As shown. Option 2 (scanning speed, repetition frequency, and number of scans are all the same: 1000mm / s, 1000kHz, 2 scans, infrared nanosecond laser power 30W, ultraviolet picosecond laser power 10W) ​​shows the following effect: Figure 6 As shown.

[0109] Figure 5 (A) and (B) show the observation results after multi-mode laser surface treatment of CFRP. First, as Figure 5 As shown in (A), the morphology image magnified to 100 μm can determine whether the resin on the CFRP surface after laser surface treatment has been completely removed; Figure 5 (B) shows a magnified morphology image at 1 μm to observe the damage caused by laser to CFRP fibers. From... Figure 5 As can be seen from (A) and (B), the resin was effectively removed while the fibers remained intact and undamaged, thus avoiding the reduction in mechanical properties caused by fiber damage.

[0110] exist Figure 6 The image shows the three-dimensional morphological observation results of the CFRP after laser treatment. Figure 6 It can be seen that after selective treatment, less resin residue remains. Considering the layered structure of the fibers, some fibers may protrude. By using multi-mode lasers to selectively treat the composite material at the micro- and nano-scale, selective removal and treatment are performed during the cleaning stage, thereby maintaining the mechanical properties of the composite material while improving the surface roughness. Ra can be increased from the initial 4.8 μm to 9.958 μm, achieving both hydrophilic and hydrophobic surfaces. The angle between the fiber arrangement direction and the scanning direction has a certain influence on the surface roughness; the roughness is greater when the scanning direction is perpendicular to the fiber direction and smaller when the scanning direction is parallel to the fiber direction. Clearly, the CFRP surface treated with multi-mode lasers is more suitable for bonding.

[0111] When the surface of the CFRP material to be processed contains too many impurities such as release agents, or when the CFRP material is large in size or thick in thickness, high-power scanning with simultaneous infrared nanosecond and ultraviolet picosecond lasers can be used for high-precision processing and activation.

[0112] When the surface of the CFRP material to be processed is relatively clean (e.g., treated with ultrasonic cleaning or alcohol wiping beforehand), and the material is small in size and thin in thickness, infrared nanosecond laser pretreatment followed by ultraviolet picosecond laser delay treatment can be adopted. Depending on the condition of the resin layer, infrared nanosecond laser can be used to remove the resin in fewer passes, while picosecond laser can be used to treat and activate the material surface in multiple passes. This can significantly improve efficiency without damaging the fibers and ensure that the surface is fully activated.

[0113] This invention combines infrared lasers, which have low absorption rate, high processing efficiency, and thermal effect as the dominant factor, with ultraviolet lasers, which have good absorption rate, precision, and low damage, and are mainly processed by photochemical methods, to form a multi-wavelength, multi-mode laser processing technology.

[0114] This invention combines the effects of different laser pulse widths on CFRP, combining nanosecond lasers, which have a longer action time, higher efficiency, and are mainly thermally active, with picosecond lasers, which can generate higher photon density, better control surface chemistry and morphology, and will not damage or burn the material, to obtain a multi-pulse-width, multi-effect laser processing technology suitable for processing CFRP surfaces.

[0115] This invention integrates two different lasers, either simultaneously with the same laser parameters or by adjusting their respective laser parameters separately. A signal generator then uses a time-delay control of the laser to treat the CFRP surface, enabling a multi-effect processing method. After thermo-coupling of the two lasers, irradiation on the target surface achieves a synergistic cleaning effect. The irradiated target surface exhibits enhanced activation properties, improving adhesion and wettability, thereby effectively increasing the adhesion and durability of CFRP to adhesives.

[0116] In this invention, the laser-induced physicochemical modification of carbon fiber composite material surface involves first removing the resin from the composite material using a 1064nm nanosecond laser to roughen the surface. Then, a picosecond high-energy laser pulse melts, vaporizes, and solidifies the material to form a surface microstructure, further improving surface quality and performance. Secondly, the plasma generated by the laser activates the surface of the composite material, which can activate the chemical bonds on the surface, increase surface roughness, thereby increasing surface energy and enhancing the adhesion and wettability of the material, making it more suitable for surface coating and bonding applications.

[0117] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A method for multi-mode laser processing, characterized in that, Includes the following steps: 1) Perform ultrasonic cleaning on the surface of the carbon fiber composite material, and then fix the carbon fiber composite material to be treated on the auxiliary displacement platform; 2) Adjust the working position of the ultraviolet picosecond laser, turn on the laser indicator light of the ultraviolet picosecond laser, so that the laser emitted by the ultraviolet picosecond laser illuminates the first test total reflection mirror and reflects it to the first detector head, and the laser signal is collected by the first energy meter to measure the laser power; 3) Adjust the working position of the infrared nanosecond laser, turn on the laser indicator light of the infrared nanosecond laser, so that the laser emitted by the infrared nanosecond laser illuminates the second test total reflection mirror and reflects it to the second detector head. The laser signal is collected by the second energy meter to measure the laser power. 4) Disassemble the first and second total reflection mirrors so that the laser emitted by the ultraviolet picosecond laser is reflected by the total reflection mirror to the polarizer, and the laser emitted by the infrared nanosecond laser is integrated at the polarizer. 5) The integrated beam is passed through the scanning galvanometer and field mirror in the beam adjustment device to output the indicator light to irradiate the surface of the carbon fiber composite material. The beam adjustment device is controlled and adjusted by the central control platform to ensure accurate focusing of the optical path and maximize the brightness of the spot acting on the carbon fiber composite material. Then, the beam and beam adjustment device are observed for polarization and light leakage. After ensuring that there is no polarization or light leakage, the ultraviolet picosecond laser and infrared nanosecond laser are turned off to complete the preparation work. 6) Turn on the picosecond laser, nanosecond laser, auxiliary laser source, and high-speed camera, and then start the digital pulse delay unit; 7) Set the pulse delay of the digital pulse delayer to 1ms; The infrared nanosecond laser parameters are set as follows: laser output wavelength 1064nm, pulse width 10ns or 60ns, repetition rate 1000kHz, and output power 30-40W; the ultraviolet picosecond laser parameters are set as follows: laser output wavelength 355nm, pulse width 10ps, repetition rate 1000kHz, and output power 5-10W; then, a digital pulse delay unit is used to send signals to the ultraviolet picosecond laser and the infrared nanosecond laser, so that the ultraviolet picosecond laser outputs picosecond laser and the infrared nanosecond laser outputs nanosecond laser. 8) The picosecond laser output from the ultraviolet picosecond laser passes through a total reflection mirror and a polarizer, while the nanosecond laser output from the infrared nanosecond laser passes through a polarizer to achieve laser beam combining. 9) The combined laser beam passes through a beam adjustment device containing a scanning galvanometer and a field mirror to complete the adjustment of the combined laser beam; 10) The adjusted and combined laser beam irradiates the surface of the carbon fiber composite material for processing and marking; at the same time, a fume purification system is used to absorb the fumes and mist generated during processing and marking; the beam adjustment device is adjusted using the central control platform; the position of the carbon fiber composite material is adjusted using an auxiliary displacement platform; simultaneously, a high-speed camera is used to observe the plasma impact phenomenon generated by the laser beam under the thermal coupling of the combined laser beam; the depth, roughness, and surface morphology of the carbon fiber composite material surface are observed and data are collected using an automatic zoom three-dimensional surface measuring instrument, and the data are input into the central control platform for analysis; 11) Further feedback adjustments are made based on the analysis results from the central control platform: Steps 7) to 10) are repeated to achieve the best treatment effect and highest treatment efficiency on the surface of carbon fiber composite materials; When there is too much release agent on the surface of carbon fiber composite materials to be processed, and the carbon fiber composite materials are large in size and thick in thickness, high-power scanning with simultaneous infrared nanosecond and ultraviolet picosecond lasers is used to perform high-precision processing and activation. When the surface of the carbon fiber composite material to be processed is clean, and the carbon fiber composite material used is small in size and thin in thickness, infrared nanosecond laser pretreatment is adopted, followed by ultraviolet picosecond laser delay treatment. In combination with the condition of the resin layer, infrared nanosecond laser is selected to remove the resin in a few passes, and picosecond laser is used to treat and activate the surface of the carbon fiber composite material in multiple passes.

2. The method as described in claim 1, characterized in that, The vertical height difference between the field lens and the surface of the carbon fiber composite material is 140-190 mm.

3. A multi-mode laser processing system for use with the method as described in claim 1 or 2, characterized in that, It consists of an ultraviolet picosecond laser, an infrared nanosecond laser, a first test total reflection mirror, a second test total reflection mirror, a first energy meter, a second energy meter, a digital pulse delay unit, a total reflection mirror, a polarizer, a beam adjustment device, an auxiliary laser source, a beam expander, a central control platform, a high-speed camera, an auxiliary displacement platform, an automatic zoom three-dimensional surface measuring instrument, and a flue gas purification device. The first energy meter has a first probe, and the second energy meter has a second probe. The digital pulse delay unit is connected to the ultraviolet picosecond laser and the infrared nanosecond laser, respectively. The first test total reflection mirror is detachably installed in the laser light path emitted by the ultraviolet picosecond laser, and the mirror surface of the first test total reflection mirror is tilted at 45° towards the ultraviolet picosecond laser; the first probe of the first energy meter is installed in the light path of the laser emitted by the ultraviolet picosecond laser reflected by the first test total reflection mirror, so that the first probe receives the energy signal of the laser emitted by the ultraviolet picosecond laser; The total reflection mirror is placed behind the first test total reflection mirror in the laser beam path emitted by the ultraviolet picosecond laser, and the mirror surface of the total reflection mirror is tilted at 45° towards the ultraviolet picosecond laser. The second total reflection mirror is detachably installed in the laser beam path emitted by the infrared nanosecond laser, and the mirror surface of the second total reflection mirror is tilted at 45° towards the infrared nanosecond laser; the second probe of the second energy meter is installed in the laser beam path reflected by the second total reflection mirror emitted by the infrared nanosecond laser, so that the second probe receives the energy signal of the laser emitted by the infrared nanosecond laser. A polarizer is placed behind the second total reflection mirror in the laser beam path emitted by the infrared nanosecond laser. The mirror surface of the polarizer is tilted at 45° and the polarizer is also located in the light path of the laser emitted by the ultraviolet picosecond laser after being reflected by the total reflection mirror. The mirror surface of the polarizer is parallel to the total reflection mirror, so that the laser emitted by the ultraviolet picosecond laser and the laser emitted by the infrared nanosecond laser can be combined into a single laser beam through the polarizer. The beam adjustment device and the auxiliary displacement platform are sequentially arranged in the optical path of the combined laser beam; the beam adjustment device includes a scanning galvanometer and a field mirror located in the optical path of the combined laser beam; the auxiliary displacement platform is used to fix the carbon fiber composite material, and the carbon fiber composite material receives the irradiation of the combined laser beam after passing through the field mirror; The auxiliary laser source is located on one side of the optical path of the combined laser. The laser emitted by the auxiliary laser source is expanded by the beam expander and then received by the high-speed camera on the other side of the optical path of the combined laser. The high-speed camera is connected to the central control platform; the central control platform is also connected to the beam adjustment device; The auxiliary displacement platform is used to fix the flue gas purification device on one side of the carbon fiber composite material. The auxiliary displacement platform is wirelessly connected to the automatic zoom three-dimensional surface measuring instrument, and the automatic zoom three-dimensional surface measuring instrument is wirelessly connected to the central control platform; The parameters of the infrared nanosecond laser are set as follows: laser output wavelength 1064nm, pulse width 10ns or 60ns, output power 30-40W, frequency of emitted infrared laser 1000kHz, and spot diameter 20-50μm. The parameters of the ultraviolet picosecond laser are set as follows: laser output wavelength 355nm, pulse width 10ps, output power 5-10W, frequency of emitted ultraviolet laser 1000kHz, and spot diameter 20-50μm.

4. The multi-mode laser processing system as described in claim 3, characterized in that, The central control platform is a computer.

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