JLA Vol:18 Iss:3 (Laser welding of zinc coated steels in an edge lap configuration)
Authors:
R. R. G. M. Pieters
Netherlands Institute for Metals Research, Joining Technology, Mekelweg 2, 2628 CD, Delft, The Netherlands
J. G. Bakels
Corus, Research, Development & Technology
M. J. M. Hermans
G. den Ouden
Delft University of Technology, 3me/MSE/Joining and Mechanical Behavior, Mekelweg 2, 2628 CD, Delft, The NetherlandsEver increasing amounts of zinc coated sheet steel are being applied in the automotive industry. At present, the main joining method used for this application is resistance spot welding. In many automotive applications there are opportunities for replacing this technique by laser welding. Duri...
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JLA Vol:18 Iss:3 (Microstructuring using femtosecond pulsed laser ablation)
Authors:
Max Groenendijk
Johan Meijer
University of Twente, PO Box 217, 7500 AE Enschede, The NetherlandsA self-induced mechanism leading to the formation of periodic microstructures has been observed during femtosecond pulsed laser ablation with a high repetition laser source. The bottom of an ablated area shows two different kinds of microstructures. A periodic ripple or a chaotic columnar structure emerges. It has been observed that the second morphology grows out of the first one dependent mainly on the amount of fired laser pulses. This transition and the influence of several parameters on it are described. Both structures have several variations in morphology. Rega...
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JLA Vol:18 Iss:3 (Modified dual-beam method for welding galvanized steel sheets in lap configuration)
Authors:
M. M. S. Gualini
S. Iqbal
Faculty of Applied Sciences, International I University, Islamabad, Pakistan
F. Grassi
Convergent Prima Industrie, Collegno (Turin), ItalyThe dual laser beams method to lap weld galvanized steel sheets is being discussed, modeled, and analyzed, involving a precursor beam and a higher-power actual beam used in tandem and generated independently or otherwise split from the same source (Nd:yttrium-aluminum-garnet or CO2 laser). The first beam cuts a slot, thus making an exit path for the zinc vapors, while the second beam welds as required. The article also presents and discusses some experiments performed ...
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JLA Vol:18 Iss:3 (Multiscale modeling of solidification during laser cladding process)
Authors:
Y. Cao
J. Choi
Department of Mechanical and Aerospace Engineering, University of Missouri-Rolla, Rolla, Missouri 65409-1060Laser cladding is an additive manufacturing process in which a laser generates a melt pool on the substrate material while a second material in a powder or wire form is injected into that melt pool. Among all laser manufacturing processes, laser cladding offers the most extensive variety of possibilities to alter a component at its surface. Despite immense potential and advancements, the process model of microstructure evolution and its coupling with macro parameters of the laser cladding process has not been fully developed. To address this...
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JLA Vol:18 Iss:3 (Optimization of optical density requirements for multiwavelength laser safety)
Authors:
Kristy L. Hayes
Robert J. Thomas
Air Force Research Laboratory, 2624 Louis Bauer Drive, Brooks City-Base, Texas 78235
Richard E. Pingry
Northrop Grumman Corporation, IT Division, 7067 Buckeye Road, Roanoke, Virginia 24018Multiwavelength laser exposures pose unique safety challenges for both laser experts and users of laser systems. We describe two methods of optimizing optical density requirements for multiwavelength laser exposures. The problem is first formulated and solved using standard mathematical programming techniques, and the results are compared to those from a simplified algorithm. The result is a method that can be efficiently i...
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JLA Vol:18 Iss:3 (The effect of processing wavelength and fluence on the microdrilling of 316 L stainless steel with a diode pumped solid state laser)
Authors:
L. Tunna
A. Khan
W. O’Neill
Institute for Manufacturing, University of Cambridge, Cambridge CB2 2RX, United Kingdom
C. J. Sutcliffe
Micromanufacturing Laboratory, University of Liverpool, Liverpool L69 3BX, United KingdomDiode pumped solid state lasers (DPSSs) with multiwavelength capability have become a powerful tool in laser material processing over the last few years. One application of high beam quality DPSS lasers that has received increased attention lately is the drilling of small diameter (<100 μm) holes through industrially important materials. Processing parameters play an important role and limit th...
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JLA Vol:18 Iss:3 (The influence of joint gap on the strength of hybrid Nd:yttrium-aluminum-garnet laser-metal inert gas welds)
Authors:
M. Wouters
Division of Manufacturing Systems Engineering, Luleå University of Technology, S-971 87 Luleå, Sweden
J. Powell
Division of Manufacturing Systems Engineering, Luleå University of Technology, S-971 87 Luleå, Sweden and Laser Expertise Ltd., Acorn Park Ind. Estate, Harrimans Lane, Nottingham NG7 2TR, United Kingdom
A. F. H. Kaplan
Division of Manufacturing Systems Engineering, Luleå University of Technology, S-971 87 Luleå, SwedenThis article presents the results of an experimental and theoretical analysis of the effect of joint gap on the strength of hybrid laser-metal inert gas welds. ...
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JLA Vol:18 Iss:3 (Thermal and microstructural aspects of the laser direct metal deposition of waspaloy)
Authors:
Andrew J. Pinkerton
Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, PO Box 88, Manchester M60 1QD, United Kingdom
Mallikarjun Karadge
Manchester Materials Science Centre, School of Materials, The University of Manchester, Grosvenor Street, Manchester M1 7HS, United Kingdom
Waheed Ul Haq Syed
Lin Li
Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, PO Box 88, Manchester M60 1QD, United KingdomA potential problem in applying the laser direct metal deposition (LDMD) technique to the f...
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JLA Vol:18 Iss:4 (Aluminum alloy welding by using a high power direct diode laser)
Authors:
N. Abe
M. Tsukamoto
Joining and Welding Research Institute, Osaka University, 11-1, Mihogaoka, Ibaraki, Osaka 567-0047, Japan
K. Maeda
K. Namba
Research and Development Center, Sumitomo Light Metal Industries, Ltd., 3-1-12 Chitose, Minato-ku, Nagoya 455-8670, Japan
J. Morimoto
School of Science and Engineering, Kinki University, 3-4-1, Kowakae, Higashiosaka, Osaka 577-8502, JapanAluminum alloys are the focus of increasing attention from the automobile industry because of their light weight, high formability, and easy recyclability. In this report, a 4 kW high power direct diode laser was used to exami...
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JLA Vol:18 Iss:4 (Cutaneous sensation threshold for 3.8 μm radiation from a short duration pulsed laser on the calves of human subjects: A pilot study)
Authors:
Thomas E. Johnson
Michael J. Roy
Department of Environmental and Radiological Health Sciences, Colorado State University, 1618 Campus Delivery, Fort Collins, Colorado 80528 and Department of Medicine, School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, Maryland 20814The objective of this study was to determine the threshold for sensing a 3.8 μm laser on the skin. The identification of the skin sensation threshold for invisible lasers is useful in providing scientific guidance to the safety community regarding accidental skin exposures. Knowledge of the level of sensation of lasers might be used to s...
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