Effect of plasma on ultrashort pulse laser material processing

Li, Chengde; Vatsya, S. R.; Nikumb, Suwas

doi:10.2351/1.2402521

Cited by 9 publications

(11 citation statements)

References 27 publications

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“…These observations are in agreement with the literature regarding the effects of plasma on the micromachining quality with ultrashort pulses. 31,32 Sun and Longtin reported that the use of inert gas improved drilling quality on Cu with fs pulses compared to drilling air by reducing plasma defocusing. 31 However, their results show taper even under inert gas conditions.…”

Section: Resultsmentioning

confidence: 99%

Comparative study of CW, nanosecond- and femtosecond-pulsed laser microcutting of AZ31 magnesium alloy stents

Demir

Previtali

2014

Biointerphases

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Magnesium alloys constitute an interesting solution for cardiovascular stents due to their biocompatibility and biodegradability in human body. Laser microcutting is the industrially accepted method for stent manufacturing. However, the laser-material interaction should be well investigated to control the quality characteristics of the microcutting process that concern the surface roughness, chemical composition, and microstructure of the final device. Despite the recent developments in industrial laser systems, a universal laser source that can be manipulated flexibly in terms of process parameters is far from reality. Therefore, comparative studies are required to demonstrate processing capabilities. In particular, the laser pulse duration is a key factor determining the processing regime. This work approaches the laser microcutting of AZ31 Mg alloy from the perspective of a comparative study to evaluate the machining capabilities in continuous wave (CW), ns- and fs-pulsed regimes. Three industrial grade machining systems were compared to reach a benchmark in machining quality, productivity, and ease of postprocessing. The results confirmed that moving toward the ultrashort pulse domain the machining quality increases, but the need for postprocessing remains. The real advantage of ultrashort pulsed machining was the ease in postprocessing and maintaining geometrical integrity of the stent mesh after chemical etching. Resultantly, the overall production cycle time was shortest for fs-pulsed laser system, despite the fact that CW laser system provided highest cutting speed

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Section: Resultsmentioning

confidence: 99%

Comparative study of CW, nanosecond- and femtosecond-pulsed laser microcutting of AZ31 magnesium alloy stents

Demir

Previtali

2014

Biointerphases

View full text Add to dashboard Cite

show abstract

“…(2) can be solved accurately and efficiently by the forward Euler method. An adequate approximation to H E is given by the energy required to melt and evaporate the unit volume of the material even in the present case of direct material removal [4,10].…”

Section: Numerical Proceduresmentioning

confidence: 99%

“…Equation (1) can be solved efficiently by evaluating the path-integral propagator [6] by the fast Fourier transform routines [7] from the amplitude at the lens location, which is determined by the pulse energy [4,7,8,10]. The calculated intensities ( , ) I r t can be used to calculate the depth ( ) z r at the radial distance r on the surface in terms of the absorption coefficient 0 a and the heat H E required to remove unit volume of the material, by solving [8] ( )…”

Section: Numerical Proceduresmentioning

confidence: 99%

“…Addition of plasma increases the distortion to the beam profile. Plasma also acts as an energy source supplying heat to the material beyond the pulse duration, which may result in melting offsetting benefits further [4]. Thus, material processing with high power ultra-short pulse lasers involves complex phenomena with both, favorable and unfavorable impact on the machined surface quality.…”

Section: Introductionmentioning

confidence: 99%

“…Balance of the competing Kerr effect and the photon-plasma scattering can result in plasma filamentation [3][4][5]. Although fragile, plasma filaments can exist in case of material processing in a sufficiently large energy range.…”

Section: Introductionmentioning

confidence: 99%

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