Modeling of Pressure Evolution During Nanosecond Laser Ablation of Metal Films

2009 ◽  
Author(s):  
Mohammad Hendijanifard ◽  
David A. Willis
Keyword(s):  
Shock Wave ◽  
Laser Ablation ◽  
Pulse Width ◽  
Metal Films ◽  
Normal Shock ◽  
Nanosecond Laser ◽  
Time Resolved ◽  
Aluminum Films ◽  
Nanosecond Laser Ablation ◽  
Fluid Properties

Nanosecond laser ablation is studied using a theoretical model combined with experimental data from laser ablation of metal films. The purpose of the research is to obtain the recoil pressure boundary condition resulting from explosive phase change. The ablation experiments are performed using a Nd:YAG laser of 1064 nm wavelength and 7 ns pulse width at full width half maximum. Three samples, 200 and 1000 nm aluminum films and 1000 nm nickel films, are used in the experiments. The transient shock wave positions are obtained by a time-resolved shadowgraph technique. A N2-laser pumped dye laser with 3 ns pulse width is used as an illumination source and is synchronized with the ablation laser to obtain the transient shock wave position with nanosecond resolution. The transient shock position is used in a model for finding the shock wave speed as well as the pressure, temperature, and velocity just behind the shock wave. A power law is used for fitting curves on the experimentally obtained shock wave position. Knowing the shock wave position, the normal shock equations are used to calculate the thermo-fluid properties behind the shock wave. The solutions are compared with the Taylor-Sedov solution for spherical shocks and the reason for the deviation is described. The thermo-fluid property results show similar trends for all tested samples. The results show that the Taylor-Sedov solution under-estimates the pressure behind the shock wave when compared to the normal shock results.

Deburring Effect of Plasma Produced by Nanosecond Laser Ablation

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Yun Zhou ◽  
Yibo Gao ◽  
Benxin Wu ◽  
Sha Tao ◽  
Ze Liu
Keyword(s):  
Shock Wave ◽  
Laser Ablation ◽  
High Spatial Resolution ◽  
Shape Change ◽  
The Other ◽  
Nanosecond Laser ◽  
Laser Induced Plasma ◽  
Nanosecond Laser Ablation ◽  
Mechanical Breaking ◽  
The Sacrifice

This paper presents an interesting nanosecond (ns) laser-induced plasma deburring (LPD) effect (from microchannel sidewalls) discovered by the authors, which has been rarely reported before in the literature. Fast imagining study has been performed on plasma produced by ns laser ablation of the bottom of microchannels. It has been found that the plasma can effectively remove burrs from the sidewall of the channels, while on the other hand microscopic images taken in this study did not show any obvious size or shape change of the channel sidewall after LPD. LPD using a sacrifice plate has also been studied, where the plasma for deburring is generated by laser ablation of the sacrifice plate instead of the workpiece. The observed laser-induced plasma deburring effect has several potential advantages in practical micromanufacturing applications, such as high spatial resolution, noncontact and no tool wear, and less possibility of damaging or overmachining useful microfeatures when removing burrs from them. The fundamental mechanisms for the observed laser-induced plasma deburring effect still require lots of further work to completely understand, which may include mechanical breaking of burrs due to high kinetic energies carried by plasma and the associated shock wave, and/or thermal transport from plasma to burrs that may cause their heating and phase change, or other mechanisms.

Picosecond and Nanosecond Laser Ablation of Mixed Tungsten/Aluminum Films

2014 ◽  
Vol 66 (2) ◽  
pp. 308-314 ◽  
Author(s):  
M. Wisse ◽  
L. Marot ◽  
R. Steiner ◽  
D. Mathys ◽  
A. Stumpp ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Nanosecond Laser ◽  
Aluminum Films ◽  
Nanosecond Laser Ablation

The influence of material properties on highly time resolved particle formation for nanosecond laser ablation

2018 ◽  
Vol 148 ◽  
pp. 193-204 ◽  
Author(s):  
Markéta Holá ◽  
Jakub Ondráček ◽  
Hana Nováková ◽  
Michal Vojtíšek-Lom ◽  
Romana Hadravová ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Material Properties ◽  
Particle Formation ◽  
Nanosecond Laser ◽  
Time Resolved ◽  
Nanosecond Laser Ablation

scholarly journals On the Dynamics of Transient Plasmas Generated by Nanosecond Laser Ablation of Several Metals

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7336
Author(s):  
Stefan Andrei Irimiciuc ◽  
Sergii Chertopalov ◽  
Michal Novotný ◽  
Valentin Craciun ◽  
Jan Lancok
Keyword(s):  
Laser Ablation ◽  
Melting Point ◽  
Nanosecond Laser ◽  
Expansion Velocity ◽  
Plasma Properties ◽  
Time Resolved ◽  
Nanosecond Laser Ablation ◽  
The Individual ◽  
Transient Plasma ◽  
The Relationship

The dynamics of transient plasma generated by UV ns-laser ablation of selected metals (Co, Cu, Ag, Bi) were investigated by the Langmuir Probe method in angle- and time-resolved modes. Multiple ionic and electronic structures were seen for all plasmas with some corresponding to anions or nanoparticle-dominated structures. The addition of an Ar atmosphere energetically confined the plasma and increased the charge density by several orders of magnitude. For pressure ranges exceeding 0.5 Pa fast ions were generated in the plasma as a result of Ar ionization and acceleration in the double layer defining the front of the plasma plume. Several correlations between the target nature plasma properties were attempted. The individual plasma structure expansion velocity increases with the melting point and decreases with the atomic mass while the corresponding charged particle densities decrease with the melting point, evidencing the relationship between the volatility of the sample and the overall abated mass.

Nanosecond Time-Resolved Measurements of Hole Opening During Laser Micromachining of Aluminum Films

2012 ◽  
Author(s):  
David A. Willis ◽  
Mohammad Hendijanifard
Keyword(s):  
Shock Wave ◽  
Pulse Width ◽  
Laser Micromachining ◽  
Nitrogen Laser ◽  
Time Resolved ◽  
Recoil Pressure ◽  
Aluminum Films ◽  
High Fluences ◽  
Transmission Imaging ◽  
Opening Process

Laser micromachining of aluminum films on glass substrates is investigated using a time-resolved transmission imaging technique with nanosecond resolution. Micromachining is performed using a 7 ns pulse-width Nd:YAG laser operating at the 1064 nm wavelength for fluences ranging from 2.2 to 14.5 J/cm2. Transmission imaging uses a nitrogen laser-pumped dye laser with a 3 ns pulse-width and 500 nm wavelength. Images are taken from the back of the sample at various time delays with respect to the beginning of the ablation process, allowing the transient hole opening process to be observed and measured. Results show that for high fluences the holes begin opening during the laser pulse and that the major portion of the holes have opened within the first 50 ns of the process. The second stage of the process is slower and lasts between 100–200 ns. The rapid hole opening process can be attributed to melt expulsion due to recoil pressure on the surface of the melt pool rather than Marangoni flow. Recoil pressure may be due to vaporization at the free surface at low fluences and phase explosion (explosive liquid-vapor phase change) at higher fluences. Measurements of the transient shock wave position are used to estimate the pressure behind the shock wave and indicate pressures at high as 89 atm during ablation. The high pressure above the laser spot results in pressure on the molten surface, leading to expulsion of the molten pool in the radial direction.

Nanosecond Laser Ablation of Titanium in Air and Water: The Time-Resolved Observation and Post-Process Characterizations

2010 ◽  
Author(s):  
Yun Zhou ◽  
Yibo Gao ◽  
Benxin Wu
Keyword(s):  
Laser Ablation ◽  
Surface Profile ◽  
Ablation Rate ◽  
Nanosecond Laser ◽  
Composition Change ◽  
Time Resolved ◽  
Laser Induced Plasma ◽  
Nanosecond Laser Ablation ◽  
Post Process ◽  
Low Efficiency

Titanium has lots of competitive applications in aerospace, biomedical and many other areas due to its special properties. However, the machining of titanium using conventional mechanical approaches often has serious tool wear and low efficiency. Laser ablation can potentially provide a good solution for titanium micromachining. In this paper, nanosecond laser ablation of titanium in air and water has been studied. The laser ablation rate, laser-induced plasma, the ablated surface profile and chemical composition change have been studied, and the results are discussed.

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