Numerical simulation of multi-pulsed femtosecond laser ablation: effect of a moving laser focus

Dong, Yiwei; Wu, Zongpu; You, Yancheng; Yin, Chunping; Qu, Wenhui; Li, Xiaoji

doi:10.1364/ome.9.004194

Cited by 21 publications

(6 citation statements)

References 15 publications

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“…The ablation depth increases linearly with the number of incident ablation cycles as cycle numbers and laser intensities increase, and the microgroove surfaces become smoother and more uniform. Since the absorption coefficient a and reflectivity r are temperature-dependent parameters, the ablation threshold fluence for a given copper is as well [15,16]. The parameters of ablation threshold fluence 𝐹𝐹 𝑡𝑡ℎ (𝑁𝑁, 𝑤𝑤(𝑧𝑧 ′ )), absorbed flux of the moving incident laser 𝐹𝐹(𝑃𝑃, 𝑤𝑤(𝑧𝑧 ′ ), 𝑒𝑒), and effective penetration depth 𝑙𝑙 𝑠𝑠 in (17) cannot be explicitly calculated from the experimental conditions because the temperature of the interactive surface changes continuously during ablation at different rates, based on the scanning speed 𝑣𝑣, laser power 𝑃𝑃, wavelength 𝜆𝜆, repetition rate 𝑓𝑓, pulse duration 𝜏𝜏, focal spot size 2𝑤𝑤 𝑜𝑜 , and copper type However, the experimental results show that the ablation depth increases linearly with the number of cycles; thus, using known parameters for specific initial ablation conditions, one can fit the theoretical formula with the experimentally acquired data to achieve a robust formula of ablation-cycle-dependent depth.…”

Section: Resultsmentioning

confidence: 99%

Z-Scanning of Multiple-Pulse Laser Ablation of Copper Study for Application in Roll-Printed Electronics

2023

JST: SSAD

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The benefits of pulsed laser ablation in advanced manufacturing have been studied in terms of intensity, adequate orientation, damped noise, and great adaptability. During ultrashort laser ablation, the interaction between a copper surface and numerous pulses was explored to establish ideal focusing conditions. We present a simple theoretical description of morphological changes in the ablated channel and illustrate its utility in real-time placement of the interactive surface at the focus during multiple-pulse laser ablation of copper. The experimental results for copper ablation depth indicate that combining a dynamic focusing mechanism and a theoretical formula for ablation-cycle-dependent ablation depth allows one to regulate the geometry of ablated channels. This model can be applied to a wide range of high-efficiency ablation systems and could be crucial in the development of a high-precision ablation system for the curved surfaces in highly scaled copper gravures used in printed electronics, which currently presents an engineering problem.

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Section: Resultsmentioning

confidence: 99%

Z-Scanning of Multiple-Pulse Laser Ablation of Copper Study for Application in Roll-Printed Electronics

2023

JST: SSAD

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“…Therefore, once the lattice temperature is 0.9 times higher than the thermodynamic critical temperature of the copper (T cr = 7696 K) at the ablation temperature, ablation is triggered off and the material region above the ablation temperature is removed. [33,34] As a result, the contour of the ablation crater is obtained.…”

Section: Surface Ablationmentioning

confidence: 99%

Effect of sample temperature on femtosecond laser ablation of copper

Dang 党,

Chen 陈,

Chen 陈

et al. 2024

Chinese Phys. B

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In this work, we conducted an experimental study supported by theoretical analysis of single laser ablation of copper to investigate the interaction between laser and material at different sample temperatures, in order to predict the ablation morphology and lattice temperature changes. For investigating the effect of sample temperature on femtosecond laser processing, we conducted experiments and simulated the thermal behavior on femtosecond laser irradiation copper using a two-temperature model. The simulated results showed that both electron peak temperature and the relaxation time required reaching equilibrium increased as initial sample temperature raised. When the sample temperature grew from 300 K to 600 K, the maximum lattice temperature at the copper surface rose by about 6500 K under femtosecond laser irradiation, and the ablation depth increased by 20%. The simulated ablation depths followed the same general trend as the experimental values. This work provides some theoretical basis and technical support for the development of femtosecond laser processing in the field of metal materials.

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“…In addition, a decreasing influence of the applied fluence at very high repetition rates and a decreasing ablation threshold were observed, without any reduction in the resulting quality as a result of heat accumulation. Due to the importance of avoiding heat accumulation for fast industrial USP laser-based machining processes, it is often investigated by thermal simulations focusing the heating of the material adjacent to the ablation [17][18][19][20][21] . Bornschlegel et al also investigated the heat distribution during USP laser ablation of 1.4301 stainless steel by measuring the workpiece temperature.…”

Section: Introductionmentioning

confidence: 99%

Computational optimization of borehole sequences for the reduction of heat accumulation in drilling processes using ultrashort pulse lasers

Lutz,

Helm,

Esen

et al. 2024

Laser-Based Micro- And Nanoprocessing XVIII

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We report on laser drilling of borehole arrays using a high-power ultrashort pulse laser with particular focus on reducing heat accumulation in the workpiece by optimizing the drilling sequence, particularly for highly efficient multi-spot drilling. Different optimization approaches are chosen to improve the drilling sequence, also comparing a simplex algorithm and an evolutionary algorithm. From a laser application point of view, we also compare drilling sequences using a single spot and up to 16-fold multi-spots generated by a spatial light modulator, as to accelerate the drilling process in terms of the number of drilled holes per second.To evaluate the temperatures generated during drilling of up to 40,000 holes in less than 76 seconds in stainless steel foil, temperatures are measured by a thermal imaging camera and subsequently compared to a COMSOL-based simulation for all optimized drilling sequences. With respect to an average temperature of 706 °C without optimization, a reduction by 252 °C, i.e., a reduction by nearly 36 % based on the Celsius scale, is achieved using a 4 × 4 beam splitter and an optimized drilling sequence with a drilling rate of 526 holes per second. In addition, using a 2 × 2 beam splitter, a temperature reduction of up to 40.5 % is achieved for a drilling process with a rate of 129 holes per second using an optimized drilling sequence.

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Numerical simulation of multi-pulsed femtosecond laser ablation: effect of a moving laser focus

Cited by 21 publications

References 15 publications

Z-Scanning of Multiple-Pulse Laser Ablation of Copper Study for Application in Roll-Printed Electronics

Z-Scanning of Multiple-Pulse Laser Ablation of Copper Study for Application in Roll-Printed Electronics

Effect of sample temperature on femtosecond laser ablation of copper

Computational optimization of borehole sequences for the reduction of heat accumulation in drilling processes using ultrashort pulse lasers

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