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Laser cleaning of RTV coating on the insulator surface by using millisecond pulse lasers

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Applied Optics
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Jialin Liu
Jialin Liu
Jialin Liu
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Xin Chen
Xin Chen
Xin Chen
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Yongqian Chen at Huazhong University of Science and Technology
Yongqian Chen
Yinghao Cui
Yinghao Cui
Yinghao Cui
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High-efficiency and high-quality removal of sulfurized silicone rubber from insulator surfaces is paramount for high-voltage power systems. To address this issue, and aiming to achieve precise and nondestructive cleaning of room temperature vulcanized (RTV) coatings, we selected millisecond laser cleaning technology in this study. Successful and efficient cleaning of the RTV coating was performed by adjusting laser parameters. Characterization techniques, including scanning electron microscopy, energy-dispersive x-ray spectroscopy, and confocal microscopy, were employed to comprehensively assess the cleaning effects and ensure the integrity of the substrate surface. The results indicate that by adjusting the scanning power combination of the high power of the millisecond pulse laser to 200 W and the low power of 150 W, the glass substrate surface maintains excellent roughness and micro-morphological features after laser cleaning, providing optimal conditions for subsequent processing and utilization. This research contributes an efficient and cost-effective solution to the insulation treatment process in high-voltage power systems.
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Research Article Vol. 63, No. 9 / 20 March 2024 / Applied Optics 2271
Laser cleaning of RTV coating on the insulator
surface by using millisecond pulse lasers
Jialin Liu,1,2Xin Chen,1,2Yongqian Chen,1,2,3,* Yinghao Cui,1,2Shirui Guo,1,2
Xiwang Wu,3AND Lujun Cui1,2
1School of Mechatronics Engineering, Zhongyuan University of Technology, Zhengzhou 451191, China
2Zhengzhou Key Laboratory of Laser Additive Manufacturing Technology, Zhengzhou 451191, China
3Henan Huanghe Whirlwind Co., Ltd., Xuchang 461500, China
*chenyq@zut.edu.cn
Received 17 December 2023; revised 22 February 2024; accepted 24 February 2024; posted 26 February 2024; published 15 March 2024
High-efficiency and high-quality removal of sulfurized silicone rubber from insulator surfaces is paramount for
high-voltage power systems. To address this issue, and aiming to achieve precise and nondestructive cleaning of
room temperature vulcanized (RTV) coatings, we selected millisecond laser cleaning technology in this study.
Successful and efficient cleaning of the RTV coating was performed by adjusting laser parameters. Characterization
techniques, including scanning electron microscopy, energy-dispersive x-ray spectroscopy, and confocal micros-
copy, were employed to comprehensively assess the cleaning effects and ensure the integrity of the substrate surface.
The results indicate that by adjusting the scanning power combination of the high power of the millisecond
pulse laser to 200 W and the low power of 150 W, the glass substrate surface maintains excellent roughness and
micro-morphological features after laser cleaning, providing optimal conditions for subsequent processing and
utilization. This research contributes an efficient and cost-effective solution to the insulation treatment process in
high-voltage power systems. © 2024 Optica Publishing Group
https://doi.org/10.1364/AO.515713
1. INTRODUCTION
Room temperature vulcanized (RTV) silicone rubber exhibits
exceptional hydrophobicity, water-repellent migratory prop-
erties, and recovery characteristics, rendering it a standard
anti-pollution flashover coating in high-voltage power sys-
tems [1,2]. However, being an organic material, RTV is
susceptible to various environmental factors such as natural
deposition, temperature fluctuations, humidity, acid rain,
and ultraviolet radiation during prolonged operation [3,4].
Consequently, these environmental influences lead to aging
phenomena including peeling, powdering, and detachment,
thereby compromising its protective function for insulators
and posing a serious threat to the safe and stable operation
of high-voltage power systems. To mitigate these issues, the
“clean and recoat” approach is widely adopted for RTV coatings
[5,6]. Nonetheless, effectively removing oxidized RTV coatings
without compromising the insulator’s surface structure and
performance remains a significant challenge [7,8].
Standard techniques for cleaning room temperature
vulcanized (RTV) coatings include chemical etching, high-
pressure water jet flushing, manual scraping, and laser cleaning.
Zhao et al. [9] prepared a cleaning and repairing agent for the
outer surface of silicone rubber insulators, which proved that
it can have the dual effect of efficient cleaning and aging repair,
improve its hydrophobicity and extend its service life. In addi-
tion, through the observation of the surface and cross-section
microstructure, it is found that the surface roughness of the
insulator is greatly reduced and the micro-cracks disappear after
the use of cleaning repair agent, which highlights a certain repair
effect. Through aging test, it can be found that the cleaning
and repairing layer has certain durability. The results show that,
compared with different cleaning methods, the cleaning repair
agent can effectively clean and repair aging insulators, improve
the anti-fouling flashover ability of insulators, and extend the
service life of silicone rubber insulators.
Laser cleaning, a technique involving the irradiation of con-
taminants with high-energy pulse lasers, offers a promising
solution for removing RTV coatings from insulator surfaces.
Through physical processes such as thermal vibration and
ablation, contaminants detach from the substrate surface via
mechanisms such as light stripping, vaporization, and plasma
ejection, resulting in effective cleaning [10,11]. Laser cleaning
presents several advantages, including precise control feedback,
safety, environmental friendliness, and adaptability to various
cleaning targets, positioning it as an ideal green cleaning tech-
nology with broad applicability. As evidenced by recent research,
the interest in laser cleaning has surged among researchers.
Studies by Fang et al. [12] and others have identified vibration
and ablation as primary mechanisms during laser cleaning of
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