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: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: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:14 Iss:1 (Physical–computational model to describe the interaction between a laser beam and a powder jet in laser surface processing)

Authors:
O. O. Diniz Neto
Array

R. Vilar
Departamento de Engenharia de Materiais, Instituto Superior Te´cnico, 1049-001 Lisboa, Portugal

Frequently laser surface treatments use a powder jet in conjunction with the laser beam. In this study we present a physical–computational model to describe the interaction between a laser beam and a powder jet. The model can be used to calculate the spatial distribution of particle temperature and laser beam attenuation at any moment and all over the region where the laser and particle beams interact. In calculating particle temperature, the attenuation of the laser beam by the particles themselves is taken into acc...

JLA Vol:18 Iss:2 (Fabrication of titanium microchannels using laser-assisted thermochemical wet etching)

Authors:
S. W. Son
M. K. Lee
K. H. Oh
S. H. Jeong
Department of Mechatronics, Gwangju Institute of Science and Technology, 1 Oryongdong Bukgu, Gwangju, 500-712 Republic of Korea

A fabrication method of titanium microchannels of an aspect ratio up to 16 and channel width of 10–30 μm is developed using laser-assisted thermochemical wet etching. For the fabrication of deep channel, the workpiece was repeatedly etched over the same path with the control of process parameters. The cross-sectional profile of the microchannel varied between a V shape and a U shape, depending largely upon the laser beam power and etchant concentration. Bubb...

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: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.