Influence of the Pulse Duration in the ps-Regime on the Ablation Efficiency of Metals

Jaeggi, B.; Neuenschwander, Beat; Schmid, M.; Muralt, Martin; Zuercher, Joseph; Hunziker, Urs

doi:10.1016/j.phpro.2011.03.118

Cited by 113 publications

(65 citation statements)

References 16 publications

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“…The results are summarized in Table 2. With a circular polarization the result is in accordance with literature [10][11][12][13]. We observe that by changing the orientation of the polarization we are improving the efficiency of ablation.…”

Section: Resultssupporting

confidence: 91%

Laserscribing of Thin Films Using Top-Hat Laser Beam Profiles

Rung¹

2013

JLMN

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Ultrashort pulse lasers have been established as precise and universal tools for the micromachining of solid materials (cutting, texturing …). For these applications the quality of the cutting cross-section is important. The use of a Gaussian beam profile and linear polarization leads to tapered cutting sidewalls. It is possible to change the polarization orientation in order to machine a material for obtaining straight and vertical sidewalls. For this purpose a specific polarization converter was used. The transformation of the polarization distribution from linear to radial and azimuthal is done by a subwavelength, binary grating creating a π phase shift between the TE and TM transmitted waves. In this paper we report on investigations on the influence of laser polarization (radial, azimuthal, circular, linear) on the ablation characteristics of molybdenum and PZT using an Yb doped crystal laser (500 fs) and compare these results with previously published results.

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Section: Resultssupporting

confidence: 91%

Laserscribing of Thin Films Using Top-Hat Laser Beam Profiles

Rung¹

2013

JLMN

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“…Also for the higher repetition rates, the surface qualities show exactly the same trend and no significant difference between the repetition rates can be observed. A simulation of the surface temperature just before a pulse will strike on the surface leads to a maximum temperature raise (2,3,4) of about 62 °C for 200 kHz and 155 °C for 1.6 MHz which is far below the critical temperature of 610 °C 22 . Therefore one can finally conclude that working with peak fluences higher than twice the optimum value will lead to bad surface qualities and the ablation efficiency will decrease as well.…”

Section: Steel Ps: Scale -Up With Single Pulsesmentioning

confidence: 93%

“…that there exists a maximum removal rate per average power 1,2 . This maximum depends on the pulse duration 3,4,5,6 whereas shorter pulses lead to higher removal rates. As working at this maximum point usually demands moderate fluences (typically in the range of 1 J/cm 2 or less) multi -spot processing or high speed scanning represent potential technologies to work at high average powers.…”

Section: Introductionmentioning

confidence: 99%

Burst mode with ps- and fs-pulses: Influence on the removal rate, surface quality, and heat accumulation

et al. 2015

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The burst mode for ps and fs pulses for steel and copper is investigated. It is found that the reduction of the energy in a single pulse (in the burst) represents the main factor for the often reported gain in the removal rate using the burst mode e.g. for steel no investigated burst sequence lead to a higher removal rate compared to single pulses at higher repetition rate. But for copper a situation was found where the burst mode leads to a real increase of the removal rate in the range of 20%. Further the burst mode offers the possibility to generate slightly melted flat surfaces with good optical properties in the case of steel. Temperature simulations indicate that the surface state during the burst mode could be responsible for the melting effect or the formation of cavities in clusters which reduces the surface quality.

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“…It discusses about lasers with a pulse duration working on nanoseconds (10 −9 s) [21], picoseconds (10 −12 s) [22] or femtoseconds (10 −15 s) [23]. Due to the very short pulses it is possible to obtain an extremely high peak power and high energy delivered during a single pulse.…”

Section: Introductionmentioning

confidence: 99%

Laser surface texturing of tool steel: textured surfaces quality evaluation

2016

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Abstract:In this experimental investigation the laser surface texturing of tool steel of type 90MnCrV8 has been conducted. The 5-axis highly dynamic laser precision machining centre Lasertec 80 Shape equipped with the nano-second pulsed ytterbium fibre laser and CNC system Siemens 840 D was used. The planar and spherical surfaces first prepared by turning have been textured. The regular array of spherical and ellipsoidal dimples with a different dimensions and different surface density has been created. Laser surface texturing has been realized under different combinations of process parameters: pulse frequency, pulse energy and laser beam scanning speed. The morphological characterization of ablated surfaces has been performed using scanning electron microscopy (SEM) technique. The results show limited possibility of ns pulse fibre laser application to generate different surface structures for tribological modification of metallic materials. These structures were obtained by varying the processing conditions between surface ablation, to surface remelting. In all cases the areas of molten material and re-cast layers were observed on the bottom and walls of the dimples. Beside the influence of laser beam parameters on the machined surface quality during laser machining of regular hemispherical and elipsoidal dimple texture on parabolic and hemispherical surfaces has been studied.

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Influence of the Pulse Duration in the ps-Regime on the Ablation Efficiency of Metals

Cited by 113 publications

References 16 publications

Laserscribing of Thin Films Using Top-Hat Laser Beam Profiles

Laserscribing of Thin Films Using Top-Hat Laser Beam Profiles

Burst mode with ps- and fs-pulses: Influence on the removal rate, surface quality, and heat accumulation

Laser surface texturing of tool steel: textured surfaces quality evaluation

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