Simulation of nanosecond laser cleaning the paint based on the thermal stress

Lu, Yao; Yang, Lijun; Wang, Maolu; Wang, Yang

doi:10.1016/j.ijleo.2020.165589

Cited by 25 publications

(11 citation statements)

References 16 publications

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“…They may reach several tens of kW for continuous lasers to up to several PW for pulsed lasers. [ 18 ] Lasers may thus generate high temperatures in a sample with an extreme spatial and temporal precision and are therefore commonly used in material sciences for surface cleaning, [ 12 ] material cutting, [ 13 ] engraving, [ 14 ] welding, [ 15 ] sintering [ 16 ] or in medicine for surgery, [ 17 ] i.e., many applications for which the local heating created by the laser is advantageous. On the contrary, when lasers are used to probe a sample as in Raman spectroscopy or fluorescence microscopy, the associated increase of temperature may alter the sample.…”

Section: Introductionmentioning

confidence: 99%

“…), the surface roughness that will change the reflection, scattering and transparency of the sample and the duration of exposure to the laser beam. [ 12–17 ]…”

Section: Introductionmentioning

confidence: 99%

“…), the surface roughness that will change the reflection, scattering and transparency of the sample and the duration of exposure to the laser beam. [12][13][14][15][16][17] All these parameters have thus to be considered during micro-Raman spectroscopy analysis.…”

mentioning

confidence: 99%

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Influence of laser shape on thermal increase during micro‐Raman spectroscopy analyses

Foucher

2021

J Raman Spectroscopy

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Micro-Raman spectrometers are used in various domains, from archaeology to space exploration. These systems use microscope objectives to focus the laser onto the sample to be analysed. Although this method drastically increases the spatial resolution down to a few hundreds of nanometres, it is also commonly admitted that this focused laser beam may heat and alter the studied material.The setting of the laser power is thus a universal problem for any micro-Raman spectroscopy user who has to find a compromise between the Raman signal intensity and the risk of thermal alteration. This parameter is not easy to set based on bibliographic references because, depending on the architecture of the system used, on the laser wavelength and on the sample, damage may occur at very different laser power levels. Here, we describe the different parameters that influence thermal increase induced by the laser and propose easy to make experiments to measure them. A series of experiments is then carried out to study the thermal alteration of various materials when exposed to a laser beam focused with the different microscope objectives of a micro-Raman system. It is shown that, except for very thin samples or powdered materials, the relevant parameters to consider are the laser power at the sample surface and the duration of exposure to the laser beam, whatever the objective used. We also demonstrate that the risk of sample alteration is almost non-existent for thick transparent materials. Interestingly, it is shown that, for semi-transparent materials, alteration may occur at lower laser power for low magnification objectives than for high magnification objectives. These results are explained by the high aperture angle of microscope objectives which induces high dispersion of the laser within the sample.

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Section: Introductionmentioning

confidence: 99%

“…), the surface roughness that will change the reflection, scattering and transparency of the sample and the duration of exposure to the laser beam. [ 12–17 ]…”

Section: Introductionmentioning

confidence: 99%

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Influence of laser shape on thermal increase during micro‐Raman spectroscopy analyses

Foucher

2021

J Raman Spectroscopy

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“…In order to realize the UV laser cleaning the painting layer feasibility, the underlying analysis and discussion are crucial and essential factors to obtain the outstanding laser cleaned effects theoretically. As for the mechanisms of UV laser cleaning, it is widely recognized that the photothermal, photochemical interactions and combination of them are underscoring effects, which has been expressed in various models detailly [38][39][40][41][42][43][44][45]. It is worth pointing out that during the period of laser cleaning, the photochemical interactions, viz.…”

Section: Resultsmentioning

confidence: 99%

A characterization of laser cleaning painting layer from steel surface based on thermodynamic model

Ding

Wang

et al. 2021

Int J Adv Manuf Technol

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In this study, the environmentally friendly nanosecond ultraviolet (UV) laser is innovatively employed laser cleaning to remove the painting layer from the AH36 steel substrate. The feasibility of UV laser cleaning the painting layer is innovatively proposed and it has been calculated by the model theoretically, followed by elaborating the prominent interaction mechanism of UV laser exactly. The initial cleaning threshold and completely cleaning threshold are 2 J/cm 2 and 5 J/cm 2 , respectively. Afterwards, the UV laser cleaned surface quality is evaluated by the scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), optical microscopy (OM) and optical profiler (OP), respectively. The mechanical properties have enhanced dramatically after laser cleaning and characterized by the Vickers hardness tester and universal testing machine. By varying laser fluences (2, 5, 7 J/cm 2 ) during laser cleaning, microstructures registering various sizes of corrugated shaped, craters and ring-shaped could be acquired. In addition, the mechanical properties analysis including rapid melting, quenching and dislocation density effects illustrates that laser cleaning could effectively increase surface microhardness, tensile strength and bending strength. Thus, laser cleaning method has emerged as a favourable means to strip painting layer in lieu of traditional methods for marine industry as well as this study could promote the development of laser cleaning in the field of marine engineering.

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“…In addition, some scholars have conducted in-depth studies on the mechanism of laser paint removal on metal substrate surface [13]. For example, Jinghua Han et al [14] used a 1064 nm nanosecond pulse laser to remove epoxy polyester mixed paint from the surface of aluminum substrate.…”

Section: Introductionmentioning

confidence: 99%

Effect of Defocused Nanosecond Laser Paint Removal on Mild Steel Substrate in Ambient Atmosphere

et al. 2021

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The obvious advantages of laser paint removal technology make it a viable alternative to traditional paint removal methods. Infrared nanosecond laser was used to remove paint from car body. The microstructure, composition, surface roughness, hardness and ablative products of the samples were analyzed. The effect of the process combination of laser defocus distance and ambient atmosphere (ambient air, compressed air and inert atmosphere) on the substrate damage and the paint removal effectiveness was explored, and the related mechanism was discussed. Defocus not only changed the fluence of laser spot but also increased the spot diameter. The effect of defocused laser paint removal on the paint and substrate was caused by the superposition of these two factors. The results show that the laser with defocus distance of +4 mm effectively removed the paint in inert atmosphere and has the least adverse effect on the substrate. The content of C element and organic components on the substrate surface was the lowest, and its surface roughness and hardness was very close to the uncoated substrate. Focused laser paint removal in ambient air caused the most serious damage to the substrate. Its surface microhardness increased by 11 HV, and the influence depth reached 37 µm. The mechanism of laser paint removal without auxiliary gas is the superposition of laser plasma effect, laser gasification effect and thermal stress effect. In open atmosphere (compressed air and inert atmosphere), the mechanism of laser paint removal is laser gasification effect and thermal stress effect. This research can provide practical references and theoretical basis for the large-scale industrial application of low/non-damage laser paint removal technology.

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Simulation of nanosecond laser cleaning the paint based on the thermal stress

Cited by 25 publications

References 16 publications

Influence of laser shape on thermal increase during micro‐Raman spectroscopy analyses

Influence of laser shape on thermal increase during micro‐Raman spectroscopy analyses

A characterization of laser cleaning painting layer from steel surface based on thermodynamic model

Effect of Defocused Nanosecond Laser Paint Removal on Mild Steel Substrate in Ambient Atmosphere

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