目的 探究变功率（P = 10 W、20 W、30 W）对铝合金表面丙烯酸聚氨酯复合漆层CO2激光清洗的影响规律。方法 建立对应功率条件下单坑与多道面扫描除漆瞬态模型,采用光学显微镜（OM）、扫描电子显微镜（SEM）、能谱仪（EDS）及白光干涉仪（WLI）对比研究仿真及实验结果,并结合高速ICCD成像揭示激光除漆机制。结果 单坑烧蚀模拟与实验除漆宽度相符,深度误差小于0.2%;单坑清洗实验截面轮廓随激光功率增加逐步平滑;三种功率单坑表面热应力仿真数值均超过了漆层抗拉强度,但热应力除漆深度不到烧蚀除漆深度的1.1%。多道面扫描除漆深度的仿真与实验结果基本吻合,P = 10 W时面漆全部除净,底漆剩余厚度约为15 µm;当P = 20 W和30 W时,复合漆层全部除净,氧化膜先后发生了开裂和大面积熔损崩落现象。多道面扫描清洗表面粗糙度随激光功率增加先减小后增大,三种功率除漆过程均未产生激光诱导等离子体现象。结论 单坑及多道面扫描激光除漆仿真计算均能较为准确地预测实验结果,P = 20 W为三种功率中能实现漆层除净的同时,氧化膜保存完整且除漆表面粗糙度最低的功率参数,CO2激光除漆过程仅包含烧蚀和热应力两种耦合清洗机制。
Abstract
The maintenance and refurbishment of composite paint layers on civil aircraft skins are critical for flight safety. Traditional chemical stripping and manual grinding methods, however, are characterized by high pollution, labor intensity, and low efficiency. While laser cleaning has emerged as a promising eco-friendly alternative, widely used nanosecond pulsed fiber or Nd:YAG lasers (wavelength: 1 064 nm) often cause thermal damage to the substrate due to the high absorption rate of aluminum alloys at near-infrared wavelengths. To address this challenge, the work aims to investigate the efficacy and mechanism of removing acrylic polyurethane composite paints from LY12 aluminum alloy surfaces with a continuous-wave CO2 laser (wavelength: 10.6 µm). The CO2 laser is selected for its high selectivity, as organic paint layers exhibit high absorption at this wavelength, whereas the metallic substrate reflects approximately 80% of the energy, theoretically protecting the anodic oxide film.
A comprehensive methodology integrating finite element simulation (with COMSOL Multiphysics) and experimental validation was employed. Transient thermal-mechanical coupled models were established for both single-pit ablation and multi-pass area scanning under variable power conditions (10 W, 20 W, and 30 W). The simulation assumed an ideal Gaussian beam distribution and considered the temperature-dependent thermal properties of the composite paint layer (total thickness: 115 µm). Key process parameters included a scanning speed of 600 mm/s and a 90% overlap rate. Experimental validation was conducted with a T40 CO2 laser, with surface integrity characterized via optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and white light interferometry (WLI). Additionally, high-speed ICCD imaging was utilized to capture the dynamic plume evolution to elucidate the cleaning mechanism.
Simulation results indicated that the calculated ablation crater widths were in good agreement with the experimental data, while the depth increased significantly with power. Notably, the simulation revealed that ablation did not cease immediately upon laser shut-off, and residual heat extended the material removal process by 21-48 µs. Although the calculated thermal stress at the pit center (approx. 39.8 MPa) exceeded the paint's tensile strength, the depth of removal attributed to thermal stress was less than 1.1% of the total depth, confirming that gasification ablation was the dominant mechanism.
In the multi-pass scanning experiments, the results matched well with the simulation predictions regarding the paint removal depth. At a low power of 10 W, the cleaning was incomplete; while the topcoat was removed, a residual primer layer of approximately 15 µm remained, accompanied by surface deposits of thermally stable β-copper phthalocyanine blue pigment. At a high power of 30 W, the paint was fully removed, but the excessive energy input caused the surface temperature to exceed the melting point of the anodic oxide film (reaching approx. 2 399 K in simulation), resulting in severe oxide spallation and increased surface roughness (Sa = 1.02 µm).
The optimal processing window was identified at 20 W. Under this condition, the composite paint layer was completely removed without damaging the substrate. The anodic oxide film remained intact, exhibiting only minor micro-cracks induced by thermal stress, which did not compromise the substrate's integrity. This parameter yielded the superior surface quality with the lowest roughness (Sa = 0.49 µm). Furthermore, comparative ICCD imaging revealed a distinct difference in mechanisms: unlike nanosecond lasers which generated expanding plasma shockwaves, the CO2 laser process produced no plasma, relying solely on a coupling mechanism of dominant ablation and auxiliary thermal stress.
In conclusion, this study validates the accuracy of the developed finite element models for predicting CO2 laser cleaning outcomes. The findings demonstrate that optimizing laser power is crucial for achieving selective paint removal, providing a theoretical and experimental foundation for the application of CO2 lasers in high-precision aviation maintenance.
关键词
激光清洗 /
CO2激光器 /
铝合金 /
丙烯酸聚氨酯漆层 /
功率 /
仿真与实验
Key words
laser cleaning /
CO2 laser /
aluminum alloy /
acrylic polyurethane paint layer /
laser power /
simulation and experiment
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参考文献
[1] 李强, 赵子铭, 刘伟军, 等. 激光除漆对铝合金基材表面质量的影响[J]. 表面技术, 2024, 53(3): 200-209.
LI Q, ZHAO Z M, LIU W J, et al.Effect of Laser Paint Removal on Surface Quality of Aluminum Alloy Substrate[J]. Surface Technology, 2024, 53(3): 200-209.
[2] DING M, WU B E, XU J, et al.Visual Inspection of Aircraft Skin: Automated Pixel-Level Defect Detection by Instance Segmentation[J]. Chinese Journal of Aeronautics, 2022, 35(10): 254-264.
[3] 吴猛, 李多生, 叶寅, 等. 激光清洗C919飞机铝锂合金蒙皮涂层[J]. 航空学报, 2025, 46(14): 329-344.
WU M, LI D S, YE Y, et al.Laser Cleaning of C919 Aircraft Al-Li Alloy Skin Coating[J]. Acta Aeronautica et Astronautica Sinica, 2025, 46(14): 329-344.
[4] 雷正龙, 孙浩然, 田泽, 等. 不同时间尺度的激光对铝合金表面油漆层清洗质量的影响[J]. 中国激光, 2021, 48(6): 0602103.
LEI Z L, SUN H R, TIAN Z, et al.Effect of Laser at Different Time Scales on Cleaning Quality of Paint on Al Alloy Surfaces[J]. Chinese Journal of Lasers, 2021, 48(6): 0602103.
[5] WANG F S, WANG Q, HUANG H Q, et al.Effects of Laser Paint Stripping on Oxide Film Damage of 2024 Aluminium Alloy Aircraft Skin[J]. Optics Express, 2021, 29(22): 35516.
[6] ZHANG T G, LIU T X, BAN G Y, et al.Effect of Scanning Speed on Laser Cleaning of Composite Paint Layer on Aluminum Alloy[J]. Optics & Laser Technology, 2024, 171: 110470.
[7] 施曙东, 杜鹏, 李伟, 等. 1064nm准连续激光除漆研究[J]. 中国激光, 2012, 39(9): 903001.
SHI S D, DU P, LI W, et al.Research on Paint Removal with 1064 nm Quasi-Continuous-Wave Laser[J]. Chinese Journal of Lasers, 2012, 39(9): 903001.
[8] HAN J H, CUI X D, WANG S, et al.Laser Effects Based Optimal Laser Parameter Identifications for Paint Removal from Metal Substrate at 1064 nm: A Multi-Pulse Model[J]. Journal of Modern Optics, 2017, 64(19): 1947-1959.
[9] 杨文锋, 常学东, 胡月, 等. 飞机蒙皮激光除漆对基材表面完整性的影响[J]. 中国激光, 2023, 50(8): 0802206.
YANG W F, CHANG X D, HU Y, et al.Effect of Laser Paint Removal of Aircraft Skin on Surface Integrity of Substrate[J]. Chinese Journal of Lasers, 2023, 50(8): 0802206.
[10] READY J F, FARSON D F.LIA handbook of laser materials processing[M]. Orlando: Laser Institute of America, 2001.
[11] 黄延禄, 杨福华, 梁工英, 等. 用原位法测定铝合金对激光的吸收率[J]. 中国激光, 2003, 30(5): 449-453.
HUANG Y L, YANG F H, LIANG G Y, et al.Using In-Situ Technique to Determine Laser Absorptivity of Al-Alloys[J]. Chinese Journal of Lasers, 2003, 30(5): 449-453.
[12] ZHU G D, XU Z H, JIN Y, et al.Mechanism and Application of Laser Cleaning: A Review[J]. Optics and Lasers in Engineering, 2022, 157: 107130.
[13] LU Y, YANG W, CHANG X, et al.Comparative Study of Infrared Nanosecond Laser Surface Paint Removal on Underwater Aluminum Alloy[J]. Journal of Cleaner Production, 2024, 466: 142782.
[14] CHEN G X, KWEE T J, TAN K P, et al.Laser Cleaning of Steel for Paint Removal[J]. Applied Physics A, 2010, 101(2): 249-253.
[15] 刘振明, 成健, 李子文, 等. CO2激光清洗2024铝合金表面复合涂层[J]. 电镀与涂饰, 2021, 40(12): 974-979.
LIU Z M, CHENG J, LI Z W, et al.Removal of Composite Coating from 2024 Aluminum Alloy Surface by CO2 Laser Cleaning[J]. Electroplating & Finishing, 2021, 40(12): 974-979.
[16] 陈菊芳, 张永康, 许仁军, 等. 轴快流CO2激光脱漆的实验研究[J]. 激光技术, 2008, 32(1): 64-66.
CHEN J F, ZHANG Y K, XU R J, et al.Experimental Research of Paint Removement with a Fast Axis Flow CO2 Laser[J]. Laser Technology, 2008, 32(1): 64-66.
[17] 薛合, 刘灿灿, 唐大兴, 等. 铝合金阳极氧化方法及成膜机理的研究进展[J]. 表面技术, 2024, 53(9): 1-10.
XUE H, LIU C C, TANG D X, et al.Research Progress of Anodic Oxidation Methods and Film Formation Mechanism of Aluminium Alloys[J]. Surface Technology, 2024, 53(9): 1-10.
[18] CHATTOPADHYAY D K, RAJU K V S N. Structural Engineering of Polyurethane Coatings for High Performance Applications[J]. Progress in Polymer Science, 2007, 32(3): 352-418.
[19] YANG J N, ZHOU J Z, SUN Q, et al.Digital Analysis and Prediction of the Topography after Pulsed Laser Paint Stripping[J]. Journal of Manufacturing Processes, 2021, 62: 685-694.
[20] 刘为桥, 鄢锉, 谢林春, 等. 脉冲激光辅助切削氧化铝陶瓷工艺参数选取的研究[J]. 中国激光, 2014, 41(7): 0703005.
LIU W Q, YAN C, XIE L C, et al.Research on Parameter Selection of Pulsed Laser-Assisted Machining of Alumina Ceramics[J]. Chinese Journal of Lasers, 2014, 41(7): 0703005.
[21] 张天刚, 李昱, 邹俊豪, 等. 民机铝合金蒙皮表面漆层激光清洗仿真与实验研究[J]. 中国激光, 2024, 51(16): 1602209.
ZHANG T G, LI Y, ZOU J H, et al.Simulation and Experimental Study on Laser Cleaning of Surface Paint Layer of Aluminum Alloy Skin for Civil Aircraft[J]. Chinese Journal of Lasers, 2024, 51(16): 1602209.
[22] 杨文锋, 何双江, 李绍龙, 等. 不同光束类型致铝合金表面漆层损伤形貌研究[J]. 激光与红外, 2023, 53(6): 869-874.
YANG W F, HE S J, LI S L, et al.Research on Damage Morphology of Aluminum Alloy Surface Paint by Different Beam Types[J]. Laser & Infrared, 2023, 53(6): 869-874.
[23] GÁLVEZ DíAZ-RUBIO F, RODRíGUEZ PÉREZ J, SÁNCHEZ GÁLVEZ V. The Spalling of Long Bars as a Reliable Method of Measuring the Dynamic Tensile Strength of Ceramics[J]. International Journal of Impact Engineering, 2002, 27(2): 161-177.
[24] 张天刚, 段俊杰, 刘天翔, 等. y向搭接率对铝合金表面复合漆层激光清洗的影响[J]. 中国激光, 2023, 50(16): 1602204.
ZHANG T G, DUAN J J, LIU T X, et al.Effect of Y-Direction Overlap Rate on Laser Cleaning of Composite Paint Layer on Aluminum Alloy Surface[J]. Chinese Journal of Lasers, 2023, 50(16): 1602204.
[25] 张天刚, 潘启越, 张志强, 等. 铝合金表面阳极氧化膜激光清洗机制分析[J]. 材料导报, 2024, 38(24): 208-217.
ZHANG T G, PAN Q Y, ZHANG Z Q, et al.Analysis of Laser Cleaning Mechanism of Anodic Oxide Film on Aluminium Alloy Surface[J]. Materials Reports, 2024, 38(24): 208-217.
[26] WANG Y Q, SHEN N G, BEFEKADU G K, et al.Modeling Pulsed Laser Ablation of Aluminum with Finite Element Analysis Considering Material Moving Front[J]. International Journal of Heat and Mass Transfer, 2017, 113: 1246-1253.
[27] ZHAO H C, QIAO Y L, DU X, et al.Laser Cleaning Performance and Mechanism in Stripping of Polyacrylate Resin Paint[J]. Applied Physics A, 2020, 126(5): 360.
[28] 张天刚, 黄嘉浩, 侯晓云, 等. 激光清洗铝合金表面复合漆层作用机制[J]. 航空学报, 2023, 44(11): 311-324.
ZHANG T G, HUANG J H, HOU X Y, et al.Mechanism for Composite Paint Layer on Aluminum Alloy Surface Cleaned by Laser[J]. Acta Aeronautica et Astronautica Sinica, 2023, 44(11): 311-324.
[29] ZHENG Z, WANG C F, HUANG G, et al.Effect of Defocused Nanosecond Laser Paint Removal on Mild Steel Substrate in Ambient Atmosphere[J]. Materials, 2021, 14(20): 5969.
[30] RADZIEJEWSKA J, STRZELEC M, OSTROWSKI R, et al.Experimental Investigation of Shock Wave Pressure Induced by a ns Laser Pulse under Varying Confined Regimes[J]. Optics and Lasers in Engineering, 2020, 126: 105913.
[31] FABBRO R, FOURNIER J, BALLARD P, et al.Physical Study of Laser-Produced Plasma in Confined Geometry[J]. Journal of Applied Physics, 1990, 68(2): 775-784.
[32] GARNOV S V, KONOV V I, TSARKOVA O G, et al.High-Temperature Measurements of Reflectivity and Heat Capacity of Metals and Dielectrics at 1064 nm[J]. Laser-Induced Damage in Optical Materials: 1996, 1997, 2966: 149-156.
[33] BERGSTRÖM D, POWELL J, KAPLAN A F H. The Absorptivity of Aluminium at CO2 Laser Wavelengths as a Function of Temperature[J]. Journal of Physics D: Applied Physics, 2013, 46(23): 235301.
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