scholarly journals Employment of Some Parameters to Enhance Laser-Drilling of Aluminum

2005 ◽  
Vol 10 ◽  
pp. 93
Author(s):  
Oday A. Hamadi
Keyword(s):  
Electric Field ◽  
Nd:Yag Laser ◽  
Laser Energy ◽  
Low Pressure ◽  
Laser Drilling ◽  
Sample Temperature ◽  
Drilling Process ◽  
Pulsed Nd:Yag Laser ◽  
Hole Depth

In this work, some parameters affecting drilling of aluminum samples by a pulsed Nd:YAG laser were studied. These parameters are multi-pulses irradiation, controlling sample temperature, low-pressure ambient and application of electric field on the sample. Results presented in this work explained that these parameters can enhance drilling process throughout increasing hole depth in aluminum samples at the same laser energy used for irradiation. 

A Parameters Optimization of the CO2 Laser Drilling Process for HDI Microvia Fabrication

2012 ◽  
Vol 214 ◽  
pp. 451-454 ◽  
Author(s):  
You Zuo Hu ◽  
Wei He ◽  
Wei Dong Xue ◽  
Zhi Hua Tao ◽  
Yu Xing Huang ◽  
...  
Keyword(s):  
Pulse Width ◽  
Printed Circuit Boards ◽  
Laser Energy ◽  
Experimental Parameter ◽  
Laser Drilling ◽  
Parameters Optimization ◽  
Laser Source ◽  
Drilling Process ◽  
Beam Diameter ◽  
Via Holes

The blind via holes formation by laser drilling is one of the key technologies for demanding high density interconnect printed circuit boards. In this paper , the drilling conditions of drilling the blind via holes and the quality of the drilled holes are examined using a CO2 laser source against the FR4 board without copper foil.We chose laser energy,pulse shot,pulse width and diameter of beam as the experimental parameter . The results showed that laser energy and beam diameter played a more important role on changing the blind vias’ diameter than pulse shot and pulse width .While the pulse shot and pulse width take more important role in changing the depth of vias.

A Coupled Stagnation Flow and Knudsen Layer Analysis for Laser Drilling

1999 ◽  
Author(s):  
John J. Batteh ◽  
Michael M. Chen ◽  
Jyoti Mazumder
Keyword(s):  
Laser Energy ◽  
Flow Analysis ◽  
Laser Drilling ◽  
Knudsen Layer ◽  
Beam Radius ◽  
Drilling Process ◽  
Stagnation Flow ◽  
Recoil Pressure ◽  
Layer Analysis ◽  
Combined Action

Abstract The application of lasers in industrial drilling processes is rapidly increasing. Consequently there is a great need to understand the fundamental physics of the laser drilling process. Recent experiments have shown that material removal occurs via the combined action of vaporization and melt expulsion due to the vaporization-induced recoil pressure. The authors (Batteh et al., 1998) developed a quasi-steady stagnation flow analysis to study the physical mechanisms of laser drilling by examining the heat transfer and fluid flow in the molten metal. This paper presents an extension of that analysis by including the effects of nonequilibrium vaporization. A Knudsen layer analysis is used to model the nonequilibrium evaporation at the liquid-vapor interface and the compressible flow outside the Knudsen layer. The analysis gives the pressure, temperature, and density jumps across the Knudsen layer. Numerical results for the combined stagnation flow and Knudsen layer analysis are shown for several different materials over a range of laser intensities commonly used in laser drilling. Drilling trends are shown as functions of the laser energy and beam radius. The results show that a significant portion of the material removed occurs through melt expulsion due to the vaporization-induced recoil pressure. The results from both the equilibrium and Knudsen layer models for vaporization are compared, and the validity of equilibrium vaporization models are discussed.

Effects of Pulsed Nd:YAG Laser Energy on Teeth: A Three-Year Follow-up Study

1993 ◽  
Vol 124 (7) ◽  
pp. 45-51 ◽  
Author(s):  
Joel M. White ◽  
Harold E. Goodis ◽  
James C. Setcos ◽  
W. Stephan Eakle ◽  
Bruce E. Hulscher ◽  
...  
Keyword(s):  
Nd:Yag Laser ◽  
Laser Energy ◽  
Pulsed Nd:Yag Laser ◽  
Follow Up Study

Pulsed Nd:YAG Laser Welding of UNS S 32205 Duplex Stainless Steel

2016 ◽  
Vol 869 ◽  
pp. 458-463
Author(s):  
Gillian da S. Crespo ◽  
Josiel L. Padilha ◽  
Celso R. Sokei ◽  
Ruis C. Tokimatsu ◽  
J. Gallego ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Laser Welding ◽  
Duplex Stainless Steel ◽  
Pulse Duration ◽  
Nd:Yag Laser ◽  
Laser Energy ◽  
Cross Sectional ◽  
Pulsed Nd:Yag Laser ◽  
Oil And Natural Gas ◽  
Pulsed Nd:Yag Laser Welding

This paper reports an experimental study of laser welding on duplex stainless steel UNS S32205 employed in the oil and natural gas industries. A pulsed Nd:YAG laser was used to weld the specimens. Bead on plate condition was used. Scanning Electron and Optical microscopy was applied to measure and analyze the cross-sectional of the weld bead. From the experimental results, it was found that the shape and size of the welded spot depend not only on the laser energy, but also on the pulse duration and the focus position. Metallographic observations showed that the microstructure of the weld metal was characterized by large ferrite grains with intra and inter-granular austenite. Large voids delimited by the molten zone boundary were observed in weld beads with low pulse duration. The heat affected zone resulting from the welding is pretty much absent and no cracks were detected.

Laser Ignition of Methane-Air Mixtures at High Pressures and Diagnostics

2005 ◽  
Vol 127 (1) ◽  
pp. 213-219 ◽  
Author(s):  
Herbert Kopecek ◽  
Soren Charareh ◽  
Maximilian Lackner ◽  
Christian Forsich ◽  
Franz Winter ◽  
...  
Keyword(s):  
Natural Gas ◽  
Nd:Yag Laser ◽  
High Pressures ◽  
Laser Energy ◽  
Spectroscopic Technique ◽  
Laser Ignition ◽  
Pulsed Nd:Yag Laser ◽  
Natural Gas Engines ◽  
Spark Plug ◽  
Induced Ignition

Methane-air mixtures at high fill pressures up to 30 bar and high temperatures up to 200°C were ignited in a high-pressure chamber with automated fill control by a 5 ns pulsed Nd:YAG laser at 1064 nm wavelength. Both, the minimum input laser pulse energy for ignition and the transmitted fraction of energy through the generated plasma were measured as a function of the air/fuel-equivalence ratio (λ). The lean-side ignition limit of methane-air mixtures was found to be λ=2.2. However, only λ<2.1 seems to be practically usable. As a comparison, the limit for conventional spark plug ignition of commercial natural gas engines is λ=1.8. Only with excessive efforts λ=2.0 can be spark ignited. The transmitted pulse shape through the laser-generated plasma was determined temporally as well as its dependence on input laser energy and properties of the specific gases interacting. For a first demonstration of the practical applicability of laser ignition, one cylinder of a 1 MW natural gas engine was ignited by a similar 5 ns pulsed Nd:YAG laser at 1064 nm. The engine worked successfully at λ=1.8 for a first test period of 100 hr without any interruption due to window fouling and other disturbances. Lowest values for NOx emission were achieved at λ=2.05 NOx=0.22 g/KWh. Three parameters obtained from accompanying spectroscopic measurements, namely, water absorbance, flame emission, and the gas inhomogeneity index have proven to be powerful tools to judge laser-induced ignition of methane-air mixtures. The following effects were determined by the absorption spectroscopic technique: formation of water in the vicinity of the laser spark (semi-quantitative); characterization of ignition (ignition delay, incomplete ignition, failed ignition); homogeneity of the gas phase in the vicinity of the ignition; and the progress of combustion.

Experimental and Parametric Evaluation of Quality Characteristics in Nd:YAG Laser Micro-Drilling of Ti6Al4V and AISI 316

2017 ◽  
Author(s):  
Suman Chatterjee ◽  
Siba Sankar Mahapatra ◽  
Anshuman Kumar Sahu ◽  
Vijay K. Bhardwaj ◽  
Ambar Choubey ◽  
...  
Keyword(s):  
Heat Affected Zone ◽  
Repetition Rate ◽  
Pulse Repetition Rate ◽  
Pulse Width ◽  
Laser Energy ◽  
Laser Drilling ◽  
Pulse Repetition ◽  
Drilling Process ◽  
Maximum Information ◽  
Aisi 316

Titanium alloy of grade-5 (Ti6Al4V) and stainless steel of grade AISI 316 have wide applications in various engineering sectors due to their favorable material properties such as low thermal conductivity, high corrosion resistance and high strength to weight ratio. The literature survey suggests that Ti6Al4V and AISI 316 have the similar field of applications and comparative study of both the materials was limited. In the present study, laser drilling of Ti6Al4V and AISI 316 have been performed using Nd:YAG millisecond laser under identical machining conditions. The control parameters considered for the study are laser energy, pulse repetition rate, pulse width and flushing pressure having each at three different levels. To reduce the total number of experimental run and obtain maximum information for the experimental trials, Taguchi’s L27 orthogonal array has been adopted. Further, the study has been focused to understand the behavior based on experimental data on similarities and differences between laser drilling process of Ti6Al4V and AISI 316 are qualitative. The outcome of experiments in terms of circularity of hole and heat affected zone (HAZ) for laser drilled holes are studied. It is observed that HAZ increases with increase in laser energy and pulse repetition rate. It may be due to a higher average power of the laser beam, which is directly proportional to laser energy and pulse repetition rate. Higher the value of laser energy, higher will be the laser thermal energy and higher HAZ. Heat affected zone (HAZ) can be minimized with low laser energy and pulse width during laser drilling of Ti6Al4V and AISI 316. From the study, it is revealed that pulse repetition rate is the most significant parameter in the formation of circularity and HAZ.

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