Microstructuring of Steel and Hard Metal using Femtosecond Laser Pulses

Pfeiffer, Manuel; Engel, Andy; Weißmantel, Steffen; Scholze, Stefan; Reiße, G.

doi:10.1016/j.phpro.2011.03.106

Cited by 16 publications

(5 citation statements)

References 2 publications

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“…Dumitru et al [2][3][4][5] determined the threshold fluence for texturation regime which permits to create nanoscale structures named LIPSS or "ripples". Pfeiffer [6], Calderón Urbina [7] and Neves [8] determined the a-thermal ablation threshold fluence using respectively a femtosecond, picosecond and nanosecond-lasers. For a purpose of improving workpieces made of tungsten carbide by adapting their tribological and physicochemical properties, we need to determine precisely these threshold fluences for performing desired double-scale structures on samples.…”

Section: Introductionmentioning

confidence: 99%

Femtosecond laser–matter interaction of tungsten carbide

et al. 2021

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We investigate the femtosecond laser–matter interaction for a tungsten carbide with 10% of cobalt. A femtosecond laser (1030 nm) with a pulse duration of 400 fs was used. For cumulated fluences between 1.4 and 4 J / c m 2 , laser-induced periodic surface structures (LIPSS) could be produced with a low ablation rate. LIPSS had a spatial period of 665 nm and an amplitude of 225 nm. The athermal ablation threshold fluence ranged from 0.35 to 11 J / c m 2 in cumulated fluence for a range between 1 and 100 pulses. Thus, dimples could be fabricated without any thermal effects. In addition, the incubation coefficient and optical penetration depth of tungsten carbide were determined. They were equal to 0.79 and 19 nm, respectively.

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Section: Introductionmentioning

confidence: 99%

Femtosecond laser–matter interaction of tungsten carbide

et al. 2021

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“…Chemical etching, in turn, requires additional, time-consuming steps related to the preparation of bespoke masks in order to achieve the final goal. Lasers, in particular ultrafast lasers that emit femtosecond and/or picosecond laser pulses, are very attractive tools in manufacturing because a single laser of this type is capable of machining a wide range of materials [2][3][4][5][6][7][8][9]. The very short interaction time of individual laser pulses with the workpiece means that the heat-affected zone (HAZ) can be minimized, providing so-called "cold" machining with very high precision and spatial resolution (even below 1 µm).…”

Section: Introductionmentioning

confidence: 99%

Interlaced Laser Beam Scanning: A Method Enabling an Increase in the Throughput of Ultrafast Laser Machining of Borosilicate Glass

Wlodarczyk

Lopes

Blair

et al. 2019

JMMP

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We provide experimental evidence that the laser beam scanning strategy has a significant influence on material removal rate in the ultrafast laser machining of glass. A comparative study of two laser beam scanning methods, (i) bidirectional sequential scanning method (SM) and (ii) bidirectional interlaced scanning method (IM), is presented for micromachining 1.1-mm-thick borosilicate glass plates (Borofloat® 33). Material removal rate and surface roughness are measured for a range of pulse energies, overlaps, and repetition frequencies. With a pulse overlap of ≤90%, IM can provide double the ablation depth and double the removal rate in comparison to SM, whilst maintaining very similar surface roughness. In both cases, the root-mean-square (RMS) surface roughness (Sq) was in the range of 1 μm to 2.5 μm. For a 95% pulse overlap, the difference was more pronounced, with IM providing up to four times the ablation depth of SM; however, this is at the cost of a significant increase in surface roughness (Sq values >5 μm). The increased ablation depths and removal rates with IM are attributed to a layer-by-layer material removal process, providing more efficient ejection of glass particles and, hence, reduced shielding of the machined area. IM also has smaller local angles of incidence of the laser beam that potentially can lead to a better coupling efficiency of the laser beam with the material.

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“…In many difficult-to-machine materials, such as WC, it is useful to know the minimum fluence at which ablation occurs so that non-ablative processes stay below that fluence threshold or so that texturing or machining-type processes stay above that threshold. Pfeiffer et al (2011) measured the WC ablation threshold (0.38 J/cm 2 ) and determined the absorption coefficient to be 4.43•10 5 cm −1 . Surface roughness could be high enough to alter the reflectivity and absorption, however, to our knowledge none have reported ablation thresholds as a function of initial surface roughness.…”

Section: Introductionmentioning

confidence: 99%

High repetition rate femtosecond laser heat accumulation and ablation thresholds in cobalt-binder and binderless tungsten carbides

Mensink

Penilla

Martínez-Torres

et al. 2019

Journal of Materials Processing Technology

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Femtosecond (fs) laser ablation has been studied for the potential of fast, high precision machining of difficult-tomachine materials like binderless tungsten carbide. Obstacles that have limited its efficiency include melting from heat accumulation (HA), particle shielding, and plasma shielding. To address HA without shielding effects, high repetition rate (57.4 MHz), ultra-low fluence fs laser irradiation is performed to study the incubation effect and subsequent HA-ablation threshold of fine-grained tungsten carbides. Exposure times on the order of 100 ms were conducted in air with fluences (1.82 to 9.09 mJ/cm 2 ) two orders of magnitude below the single fs pulse ablation thresholds reported in literature (0.4 J/cm 2 ). Heat accumulation at high repetition rate explains the ultra-low fluence melt threshold behavior resulting in melt crowns around ablated holes and grooves. The results of this study aid in predicting heat buildup in high repetition rate laser irradiation for applications that wish to achieve high ablation rates of difficult-to-machine, ultrahard materials and help enable shaping of binderless tungsten carbide for use in applications too extreme for bindered tungsten carbide.

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Microstructuring of Steel and Hard Metal using Femtosecond Laser Pulses

Cited by 16 publications

References 2 publications

Femtosecond laser–matter interaction of tungsten carbide

Femtosecond laser–matter interaction of tungsten carbide

Interlaced Laser Beam Scanning: A Method Enabling an Increase in the Throughput of Ultrafast Laser Machining of Borosilicate Glass

High repetition rate femtosecond laser heat accumulation and ablation thresholds in cobalt-binder and binderless tungsten carbides

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