scholarly journals High-quality net shape geometries from additively manufactured parts using closed-loop controlled ablation with ultrashort laser pulses

2020 ◽  
Vol 9 (1-2) ◽  
pp. 101-110 ◽  
Author(s):  
Daniel Holder ◽  
Artur Leis ◽  
Matthias Buser ◽  
Rudolf Weber ◽  
Thomas Graf
Keyword(s):  
Surface Roughness ◽  
Closed Loop ◽  
High Surface ◽  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Minimum Thickness ◽  
High Quality ◽  
Surface Optical ◽  
The Individual ◽  
Ultrashort Laser

AbstractAdditively manufactured parts typically deviate to some extent from the targeted net shape and exhibit high surface roughness due to the size of the powder grains that determines the minimum thickness of the individual slices and due to partially molten powder grains adhering on the surface. Optical coherence tomography (OCT)-based measurements and closed-loop controlled ablation with ultrashort laser pulses were utilized for the precise positioning of the LPBF-generated aluminum parts and for post-processing by selective laser ablation of the excessive material. As a result, high-quality net shape geometries were achieved with surface roughness, and deviation from the targeted net shape geometry reduced by 67% and 63%, respectively.

scholarly journals High-quality percussion drilling with ultrashort laser pulses

2021 ◽  
Vol 127 (9) ◽  
Author(s):  
A. Feuer ◽  
R. Weber ◽  
R. Feuer ◽  
D. Brinkmeier ◽  
T. Graf
Keyword(s):  
Stainless Steel ◽  
Laser Fluence ◽  
Ablation Threshold ◽  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
High Quality ◽  
Edge Quality ◽  
Ultrashort Laser ◽  
Percussion Drilling

AbstractThe influence of the laser fluence on the quality of percussion-drilled holes was investigated both experimentally and by an analytical model. The study reveals that the edge quality of the drilled microholes depends on the laser fluence reaching the rear exit of the hole and changes with the number of pulses applied after breakthrough. The minimum fluence that must reach the hole’s exit in order to obtain high-quality microholes in stainless steel was experimentally found to be 2.8 times the ablation threshold.

scholarly journals Post-processing of additively manufactured metal parts by ultrashort laser pulses for high-quality net shape geometries and advanced functionality

2021 ◽  
Vol 1135 (1) ◽  
pp. 012005
Author(s):  
Daniel Holder ◽  
Matthias Buser ◽  
Artur Leis ◽  
Rudolf Weber ◽  
Thomas Graf
Keyword(s):  
Surface Roughness ◽  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Water Repellent ◽  
Support Structures ◽  
Post Processing ◽  
Shape Accuracy ◽  
Ultrashort Pulse Laser ◽  
Metal Parts ◽  
Ultrashort Laser

Abstract Additive manufacturing by means of laser-based powder bed fusion (LPBF) offers high flexibility with respect to the generation of individualized and light-weight metal parts. However, the produced parts are typically attached to support structures and deviate a few tens of micrometers from the targeted final component in geometrical net shape and surface roughness due to the melt-based fusion process. Therefore, different post-processing techniques were examined in the past to resolve the mentioned quality drawbacks. In our work, we investigated the potential of post-processing of LPBF-generated Ti6Al4V parts with ultrashort pulse laser ablation. As a result, the support structures were effectively removed, the surface roughness was reduced by 81% and complex geometries with high shape accuracy were fabricated. Furthermore, the LBPF-generated parts were laser surface structured to investigate the potential of post-processing with ultrashort laser pulses for advanced functionality, such as water-repellent surfaces. The generation of surface structures on the LPBF-generated Ti6Al4V part changed the wetting behaviour from hydrophilic to hydrophobic with an increased contact angle from 73° up to 130°.

scholarly journals Water in contact with the backside of a silicon substrate enables drilling of high-quality holes through the substrate using ultrashort laser pulses

2020 ◽  
Vol 28 (2) ◽  
pp. 1394
Author(s):  
Miku J. O. Laakso ◽  
Simone Pagliano ◽  
Umer Shah ◽  
Gustaf E. Mårtensson ◽  
Göran Stemme ◽  
...  
Keyword(s):  
Silicon Substrate ◽  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
High Quality ◽  
Ultrashort Laser

scholarly journals Rod–sphere cluster irradiation with femtosecond laser pulses: cut and paste at the nanoscale

Nanophotonics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3153-3159 ◽  
Author(s):  
Pablo Díaz-Núñez ◽  
Sabrina L. J. Thomä ◽  
Guillermo González-Rubio ◽  
Olivia Borrell-Grueiro ◽  
Roland P. M. Höller ◽  
...  
Keyword(s):  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Surface Enhanced ◽  
Fine Control ◽  
Degree Of Control ◽  
The Individual ◽  
Ultrashort Laser ◽  
Individual Particles ◽  
Selection Of

Abstract We report on the irradiation of gold rod–sphere assemblies with ultrashort laser pulses, producing structures that are very difficult to obtain by other methods. The optical response of these assemblies displays several peaks arising from the interaction of the plasmon modes of the individual particles, offering thus great flexibility to control the energy deposited on the individual particles. Judicious selection of the wavelength and fluence of the laser pulses allow fine control over the changes produced: the particles can be melted, welded and/or the organic links cleaved. In this way, it is possible to generate structures “à la carte” with a degree of control unmatched by other synthetic protocols. The method is exemplified with gold nanoparticles, but it can be easily implemented on particles composed of different metals, widening considerably the range of possibilities. The final structures are excellent candidates for surface-enhanced spectroscopies or plasmonic photothermal therapy as they have a very intense electric field located outside the structure, not in the gaps.

Welding characteristics of foturan glass using ultrashort laser pulses

2012 ◽  
Author(s):  
Isamu Miyamoto ◽  
Kristian Cvecek ◽  
Yasuhiro Okamoto ◽  
Michael Schmidt ◽  
Henry Helvajian
Keyword(s):  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Ultrashort Laser

Evaluation of Chip-Breakers Manufactured by Ultrashort Laser Pulses in Cemented Carbide Tools

2017 ◽  
Author(s):  
Marcelo Bertolete Carneiro ◽  
Patrícia Alves Barbosa ◽  
Ricardo Samad ◽  
NIlson Vieira ◽  
Wagner de Rossi ◽  
...  
Keyword(s):  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Cemented Carbide ◽  
Cemented Carbide Tools ◽  
Ultrashort Laser

Picosecond Single-Photon and Femtosecond Two-Photon Pulsed Laser Stimulation for IC Characterization and Failure Analysis

2009 ◽  
Author(s):  
V. Pouget ◽  
E. Faraud ◽  
K. Shao ◽  
S. Jonathas ◽  
D. Horain ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Single Photon ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Laser Stimulation ◽  
Two Photon ◽  
Resolution Improvement ◽  
Ultrashort Laser

Abstract This paper presents the use of pulsed laser stimulation with picosecond and femtosecond laser pulses. We first discuss the resolution improvement that can be expected when using ultrashort laser pulses. Two case studies are then presented to illustrate the possibilities of the pulsed laser photoelectric stimulation in picosecond single-photon and femtosecond two-photon modes.

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