JLA Vol:25 Iss:1 (Spatial analysis of the back reflected laser light during CO₂-laser cutting of metal sheets)

Authors:
David Schindhelm
Graduate School of Excellence Advanced Manufacturing Engineering in Stuttgart (GSaME), Universita¨t Stuttgart, D-70569 Stuttgart, Germany and Institut fu¨r Strahlwerkzeuge (IFSW), Universita¨t Stuttgart, Pfaffenwaldring 43, D-70569 Stuttgart, Germany

Rudolf Weber
Thomas Graf
Institut fu¨r Strahlwerkzeuge (IFSW), Universita¨t Stuttgart, Pfaffenwaldring 43, D-70569 Stuttgart, Germany

During laser material processing such as laser welding or cutting, it is known that the whole laser power is not only absorbed in or transmitted through the interaction zone, but a significant percentage is also reflected back ...

JLA Vol:25 Iss:1 (Wettability modification of electrospun poly(ε-caprolactone) fiber by femtosecond laser irradiation)

Authors:
Lingna He
Dave F. Farson
Laboratory for Multiscale Processing and Characterization, The Ohio State University, 1248 Arthur E Adams Drive, Columbus, Ohio 43221 and Department of Materials Science and Engineering, The Ohio State University, 477 Watts Hall, 2041 College Road, Columbus, Ohio 43210

Jian Chen
Materials Science and Technology Division, Oak Ridge National Laboratory, One Bethel Road, P.O. Box 2008, MS-6095, Oak Ridge, Tennessee 37831-6095

John J. Lannutti
Department of Materials Science and Engineering, The Ohio State University, 477 Watts Hall, 2041 College Road, Columbus, Ohio 43210

Stan I. Rokhlin
Labora...

JLA Vol:25 Iss:1 (Fatigue crack propagation in laser alloyed ductile cast iron surface)

Authors:
Zheng-yang Li
Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China and Key Laboratory for Advanced Manufacturing by Materials Processing Technology, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, People's Republic of China

Hai-yan Zhao
Yu Gu
Min-lin Zhong
Bin Zhang
Hong-jun Zhang
Wen-jin Liu
Key Laboratory for Advanced Manufacturing by Materials Processing Technology, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, People's Republic of China

Zhi-yuan Ren
Ming-jiang Yang

JLA Vol:25 Iss:1 (Implementation of a novel scan localization system for wireless sensor networks)

Authors:
K. Sun
W. Huang
Sachula Meng
Y. Xiao
M. T. Wang
Z. Xiao
Inner Mongolia University, Hohhot 010021, China

A novel localization scheme called laser beam scan localization by combining grid and light (laser) with mobile localization policy for wireless sensor networks is designed. The scheme utilizes a moving location assistant (LA) with a laser beam, through which the deployed area is scanned. The LA sends identities to unknown nodes to obtain the locations of sensor nodes. High localization accuracy can be achieved without the aid of expensive hardware on the sensor nodes, as required by other localization systems...

JLA Vol:25 Iss:1 (Theoretical analysis of multiple-pulse thermal damage thresholds of the retina)

Authors:
C. D. Clark
TASC Inc., 4141 Petroleum Road, Suite 4007 Fort Sam Houston, Texas 78234

W. J. Marshall
Laser Safety Specialties, Wilmington, Delaware 19810

R. J. Thomas
Air Force Research Laboratory, 711 HPW/RHDO, 4141 Petroleum Road, Fort Sam Houston, Texas 78234

In this paper, we present a theoretical analysis of multiple-pulse thermal damage thresholds based on the Arrhenius integral damage model. We consider the dependence of thresholds on both the number of pulses and the pulse spacing and show that the trends can be understood by considering the thermal relaxation time. The biological data that exists in the multiple-pulse therma...

JLA Vol:25 Iss:1 (Review on laser drilling I. Fundamentals, modeling, and simulation)

Authors:
Wolfgang Schulz
Fraunhofer Institute for Laser Technology, ILT, Aachen, Germany and Nonlinear Dynamics of Laser Processing, RWTH Aachen University, 52074 Germany

Urs Eppelt
Nonlinear Dynamics of Laser Processing, RWTH Aachen University, 52074 Germany

Reinhart Poprawe
Fraunhofer Institute for Laser Technology, ILT, Aachen, Germany and Nonlinear Dynamics of Laser Processing, RWTH Aachen University, 52074 Germany

High peak power lasers have been used for years for ablating matter. The most relevant application of this process is laser marking. Marking meets the demands of applications although the quality of ablation has potential to b...

JLA Vol:25 Iss:5 (Stoichiometric 6H-SiC thin films deposited at low substrate temperature by laser ablation)

Authors:
J. G. Quin˜ones-Galva´n
Physics Department, CINVESTAV-IPN, Apdo. Postal 14-740 Me´xico, D.F. 07360, Mexico

J. S. Arias-Cero´n
CICATA-IPN, Unidad Legaria, Me´xico D.F. 11500, Mexico

F. de Moure-Flores
Facultad de Qui´mica, Materiales, Universidad Auto´noma de Quere´taro, Quere´taro 76010, Mexico

A. Herna´ndez-Herna´ndez
A. Guille´n-Cervantes
J. Santoyo-Salazar
J. G. Mendoza-Alvarez
M. Mele´ndez-Lira
Physics Department, CINVESTAV-IPN, Apdo. Postal 14-740 Me´xico, D. F. 07360, Mexico


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JLA Vol:25 Iss:5 (Numerical and experimental study of the effect of groove on plasma plume during high power laser welding)

Authors:
Cai Yan
Xie Wen-Jing
Wu Yue
Sun Da-Wei
Wu Yixiong
Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240, China and Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai 200240, China

The influence of groove on the static feature and dynamic behavior of plasma plume during high power CO₂ laser welding process was studied using a hydrodynamic three-dimensional model and corresponding experiments. The temperature, composition, and velocity of plasma plume along the incident path of laser beam were computed. The static morphology of plasma plume was analyzed through both models ...

JLA Vol:25 Iss:5 (Heat transfer and fluid flow in additive manufacturing)

Authors:
A. Raghavan
H. L. Wei
T. A. Palmer
T. DebRoy
Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802

In laser-based direct energy deposition additive manufacturing, process control can be achieved through a closed loop control system in which thermal sensing of the melt pool surface is used to adjust laser processing parameters to maintain a constant surface geometry. Although this process control technique takes advantage of important in-process information, the conclusions drawn about the final solidification structure and mechanical properties of the deposited material are li...

JLA Vol:25 Iss:5 (Laser remote-fusion cutting with solid-state lasers)

Authors:
A. Wagner
M. Lu¨tke
A. Wetzig
Fraunhofer Institute for Material and Beam Technology IWS, Winterbergstraße 28, 01277 Dresden, Germany

L. M. Eng
Institute of Applied Photophysics, TU Dresden, George-Ba¨hr-Straße 1, 01062 Dresden, Germany

A laser remote cutting process is analyzed, which differs significantly from established laser cutting processes. On the one hand, no cutting gas is needed and a high working distance is realized. On the other hand—in opposite to conventional laser remote cutting—sheets of metal with thicknesses above 1 mm can be cut in one step. Examinations were carried out at the...