High precision deep drilling with ultrashort pulses

Foehl, Christian; Dausinger, Friedrich

doi:10.1117/12.540506

Cited by 30 publications

(4 citation statements)

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“…It was observed that ns laser pulses could also produce similar results for certain materials. Fohl and Dausinger [95] investigated the influence of high repetition rate on drilling efficiency and hole quality. It was found that ripple formation is more dominant in perpendicular polarization and circularly polarized laser beam reduce the effect of laser on the hole exit.…”

Section: Metalsmentioning

confidence: 99%

Laser Beam MicroMachining (LBMM) – A review

Mishra¹,

Yadava

2015

Optics and Lasers in Engineering

238

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Section: Metalsmentioning

confidence: 99%

Laser Beam MicroMachining (LBMM) – A review

Mishra¹,

Yadava

2015

Optics and Lasers in Engineering

238

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Section: Introductionmentioning

confidence: 99%

“…Laser-material interactions are known to be strongly influenced by the fluence, pulse duration, wavelength and polarization of the incident laser beam [7][8][9]. In particular, polarization affects both the efficiency and the quality of ultrashort-pulse microprocesses, including helical drilling and cutting [9][10][11][12]. For example, drilling high-aspectratio (depth/diameter) microscopic holes in metal with linearly polarized ultrashort-pulse lasers produces anisotropic profiles [10,11].…”

Section: Introductionmentioning

confidence: 99%

Laser microprocessing of steel with radially and azimuthally polarized femtosecond vortex pulses

Allegre¹,

Perrie²,

Edwardson³

et al. 2012

J. Opt.

116

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The use of a liquid-crystal spatial light modulator (SLM) device to convert a linearly polarized femtosecond laser beam into a radially or azimuthally polarized vortex beam is demonstrated. In order to verify the state of polarization at the focal plane, laser induced periodic surface structures (LIPSS) are produced on stainless steel, imprinting the complex vectorial polarization structures and confirming the efficacy of the SLM in producing the desired polarization modes. Stainless steel plates of various thicknesses are micromachined with the radially and azimuthally polarized vortex beams and the resulting cut-outs are analysed. The process efficiency and quality of each mode are compared with those of circular polarization. Radial polarization is confirmed to be the most efficient mode for machining high-aspect-ratio (depth/width > 3) channels thanks to its relatively higher absorptivity. Following our microprocessing tests, liquid-crystal SLMs emerged as a flexible off-the-shelf tool for producing radially and azimuthally polarized beams in existing ultrashort-pulse laser microprocessing systems.

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“…This simplified characterization of the beam propagation is sufficient for the intended feasibility analysis. A more detailed discussion of the working principle of the helical drilling optics 44 , 45 , 50 and the resulting 3D movements of the beam is not necessary and is beyond the scope of this paper.…”

Section: Measurement Methodology and Definitionsmentioning

confidence: 99%

Feasibility assessment of parallelized helical drilling

2023

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With the average power of commercial ultrafast lasers reaching the kW-level, process parallelization is required to avoid detrimental quality issues, such as caused by heat accumulation. This is especially relevant in the case of helical drilling, as the processing strategy is only employed when precise geometry, high-quality surface finish, tight tolerances, and high reproducibility are a priority. We illustrate that parallelization by means of a multipass process is conceptually attractive for pulsed drilling processes, but also challenging due to limitations imposed by the properties of appropriate beam-steering devices. While paraxial beam propagation methods applied to the suggested setup predict no aberrations, deviations from the idealized solution are a concern. Our experimental proof-of-principle investigations show that parallelization by means of a deflector preceding the helical drilling optics is possible while ensuring nearly identical processing parameters for all parallelly processed boreholes.

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High precision deep drilling with ultrashort pulses

Cited by 30 publications

References 0 publications

Laser Beam MicroMachining (LBMM) – A review

Laser Beam MicroMachining (LBMM) – A review

Laser microprocessing of steel with radially and azimuthally polarized femtosecond vortex pulses

Feasibility assessment of parallelized helical drilling

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