JLA Vol:2 Iss:2 (Binary Phase Gratings for Materials Processing)

Authors:
Paul J. Patt
Array

The feasibility of using a diffractive optical element, a phase grating, as a beam handling device for use in industrial laser material processing is examined. The binary phase grating is an efficient beam splitting device and is useful in many materials processing operations (welding, cutting, soldering, drilling) where a high degree of parallelism could significantly improve process throughput. Overall efficiency of etched quartz binary gratings agrees well with published predictions (nominal 70–90%). Copies of the grating formed in PMMA (acrylic) survived preliminary life tests (more than 1000 9‐J pulses from a commercial multimode N...

JLA Vol:17 Iss:3 (Laser beam analysis in direct metal deposition process)

Authors:
Huan Qi
Jyoti Mazumder
Center for Laser Aided Intelligent Manufacturing, Department of Mechanical Engineering, The University of Michigan, Ann Arbor, Michigan 48109

Larry Green
Spiricon, Inc., Logan, Utah 84341

Gary Herrit
II-VI, Inc., Saxonburg, Pennsylvania 16056

The quality of a laser beam profile and its stability play fundamental roles in laser material processing. Beam reflections may dramatically affect the beam quality under certain material processing conditions. In this study, experiments were carried out to examine the variations of the continuous wave CO₂ laser beam profile during the direct metal...

JLA Vol:21 Iss:4 (Contributions of Charles Townes’ research to nonlinear optics)

Authors:
Elsa Garmire
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA

Nonlinear optics was profoundly influenced by early work of Charles Townes and his group at Massachusetts Institute of Technology from 1961 to 1967. His foundational contribution was the realization that coherent molecular oscillations resulted from stimulated Raman scattering, leading to the introduction of stimulated Brillouin scattering. Self-trapping of light beams and self-steeping of light pulses in nonlinear materials were two other important innovations. Some applications today of these early ideas are outlined.

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:24 Iss:4 (Laser-assisted nanofabrication of carbon nanostructures)

Authors:
Yun Shen Zhou
Wei Xiong
Jongbok Park
Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0511, USA

Min Qian
Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska, 68588-0511, USA and Department of Physics, East China Normal University, Shanghai 200062, People’s Republic of China

Masoud Mahjouri-Samani
Yang Gao
Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0511, USA

Lan Jiang
Department of Mechanical and Automation Engineering, Beijing Institute of Technology, Bei...

JLA Vol:5 Iss:1 (Heat Flow in Laser Die Blank Welding)

Authors:
Y.‐S. Yang
C. R. Hsu
C. E. Albright
Y. Kuroda

Laser welded die blanks are finding increased usage in many industrial applications. This investigation was undertaken to establish a simplified means of calculating thermal cycles experienced in the fusion and heat affected zones on laser welds typically used in die blank welding. A planar solution domain perpendicular to the direction of travel was selected to simplify the finite element calculations. The resulting calculation technique provided reasonably accurate prediction of the thermal cycles measured by Moon and Metzbower, and the size of fusion zones and heat affected zones o...

JLA Vol:15 Iss:4 (Welding of thick austenitic stainless steel using Nd:yttrium–aluminum–garnet laser with filler wire and hybrid process)

Authors:
Tommi Jokinen
Miikka Karhu
VTT Industrial Systems, P.O. Box 17021, FIN 53851 Lappeenranta, Finland

Veli Kujanpa¨a¨
Lappeenranta University of Technology, P.O. Box 20, FIN 53851 Lappeenranta, Finland

Autogenous laser welding has shown many advantages over traditional welding methods in numerous applications. However, there could be even more applications, but due to the power levels of present high power lasers, depth of penetration is limited. One way to overcome this limitation is to use multipass laser welding, in which a narrow gap and a filler wire are applied. By this process thick sections can be welded with a smaller heat inpu...

JLA Vol:19 Iss:4 (Experimental observation of keyhole shapes in the laser welding of aluminum blanks)

Authors:
B. J. Aalderink
Netherlands Institute for Metals Research, P.O. Box 217, 7500 AE Enschede, The Netherlands

R. G. K. M. Aarts
University of Twente, Laboratory of Mechanical Automation, P.O. Box 217, 7500 AE Enschede, The Netherlands

D. F. de Lange
Netherlands Institute for Metals Research, P.O. Box 217, 7500 AE Enschede, The Netherlands

J. Meijer
University of Twente, Laboratory of Mechanical Automation, P.O. Box 217, 7500 AE Enschede, The Netherlands

A camera-based in situ monitoring system for the Nd:yttrium–aluminum–garnet laser keyhole welding process of aluminium has been developed. The...

JLA Vol:22 Iss:4 (Erratum: “Weld strength improvement for Al alloy by using laser weaving method” [J. Laser Appl. 22(3), 116 (2010)])

Authors:
Kwang-Deok Choi
Young-Nam Ahn
Cheolhee Kim
Advanced Welding & Joining Technology Research Team, Korea Institute of Industrial Technology, 7-47 Songdo-Dong, Yeonsu-Gu, Incheon 406-840, Korea

JLA Vol:7 Iss:2 (Fraunhofer resource center for laser technology ‐ USA)

Authors:
Frank W. Kuepper
Fraunhofer Resource Center for Laser Technology, Ann Arbor, MI, U.S.A.