JLA Vol:18 Iss:1 (The effect of shielding gas composition on welding performance and weld properties in hybrid CO<sub>2</sub> laser–gas metal arc welding of carbon manganese steel)
Authors:
Anna Fellman
Laser Processing Laboratory, Department of Mechanical Engineering, Lappeenranta University of Technology, FIN-53850 Lappeenranta, Finland
Veli Kujanpa¨a¨
Laser Processing Laboratory, Department of Mechanical Engineering, Lappeenranta University of Technology and VTT Industrial Systems, FIN-53850 Lappeenranta, FinlandMetals industries producing large structures currently have a particular interest in hybrid laser welding processes, which possess advantages compared with conventional methods of welding. One major benefit is a reduction in deformation that enables the amount of postweld finishing work to be reduced. Assembly then also ...
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JLA Vol:18 Iss:1 (Three-dimensional analytical model on laser-powder interaction during laser cladding)
Authors:
Yan-Lu Huang
Jian Liu
Nai-Heng Ma
Jian-Guo Li
School of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai, China 200030To compute the attenuation of laser power by powder stream and the temperature distribution of the powder particles arriving at different sites on the surface of the workpiece, a three-dimensional analytical model was presented based on Lambert-Beer theorem, Mie’s theory, and heat equilibrium principle. The obtained results revealed that for a given stream spread and speed of powder particles, the laser intensity distribution of laser spot and the temperature distribution of the powder part...
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JLA Vol:18 Iss:2 (A high power diode laser-based technique for the bonding of composite patches to aluminium alloys on various military aircraft)
Authors:
J. Lawrence
Wolfson School of Mechanical and Manufacturing Engineering, Loughborough University, Leicestershire LE11 3TU, EnglandA rapid, effective, and repeatable technique for repairing the damaged skins of various military aircraft, both fixed and rotary winged, using high power diode laser (HPDL) radiation is described herein. The HPDL beam was traversed across the surface of an APC-2 repair patch, thereby melting a thermoplastic adhesive placed inbetween the repair patch and an Alclad substrate, consequently bonding the repair patch to the Alclad substrate. When subjected to single lap shear tests, the shear strength of the bond generated with the HPDL radiation was 47....
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JLA Vol:18 Iss:2 (CO<sub>2</sub> laser beam cutting of steels: Material issues)
Authors:
Murali Manohar
Mittal Steel USA R&D, East Chicago, Indiana 46312Laser beam cutting and its advantages along with its relevance to worldwide trends in manufacturing are introduced. Results of efforts to identify material-related factors that render steel suitable for laser cutting are described. Key material requirements for both hot-strip and discrete plate products have been summarized using data collected over several years based on anecdotal information as well as experimental results. It has become clear that near-zero residual stresses and a minimum level of residual elements (Cu, Ni, and Cr) are necessary to obtain clean pierces and consistent cut quality in thick ...
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JLA Vol:18 Iss:2 (Effect of process parameter on turbulent transport in a laser surface alloying process)
Authors:
Dipankar Chatterjee
Department of Mechanical Engineering, Indian Institute of Technology, Kharagpur 721302, India
Nilanjan Chakraborty
Department of Engineering, Cambridge University, Cambridge CB2 1PZ, United Kingdom
Suman Chakraborty
Department of Mechanical Engineering, Indian Institute of Technology, Kharagpur 721302, IndiaA three-dimensional, transient numerical model is used for analyzing turbulent momentum, heat, and mass transport in typical laser surface alloying processes. The Reynolds averaged conservation equations are solved using a finite volume approach. The turbulent transport is accounted for by a suitably modified...
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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 KoreaA 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...
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JLA Vol:18 Iss:2 (In-process monitoring and adaptive control for prevention of through-holes in full-penetration lap welds of aluminum alloy sheets)
Authors:
Yousuke Kawahito
Seiji Katayama
Joining and Welding Research Institute (JWRI), Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047, JapanThe availability of adaptive control for microspot lap welding of A3003 aluminum alloy sheets of 0.1 mm in thickness with a pulsed fundamental yttrium-aluminum-garnet laser beam was investigated with the objective of the stable production of sound full-penetration spot welds without through-holes. Two full-penetration welds with through-holes were produced among 20 samples subjected to a normal pulse laser beam. The in-process monitoring results of the reflected light and heat radiation signals showed that the minimu...
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JLA Vol:18 Iss:2 (Investigation of the effects of nonconventional beam geometries in laser surface treatment of ceramics: Theoretical analysis)
Authors:
D. Triantafyllidis
Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Manchester M60 1QD, United Kingdom and Corrosion and Protection Centre, School of Materials, The University of Manchester, Manchester M60 IQD, United Kingdom
L. Li
Laser Processing Research Center, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Manchester M60 1QD, United Kingdom
F. H. Stott
Corrosion and Protection Centre, School of Materials, The University of Manchester, Manchester M60 1QD, United KingdomLaser surface treatment of ceramics by melting and re...
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JLA Vol:18 Iss:2 (Laser ablation of silicon wafer with a water microdrop)
Authors:
Kouki Shimizu
Kunimitsu Takahashi
Photonics and Materials Research Department, Institute of Research and Innovation, 1201 Takada, Kashiwa, Chiba 277-0861, Japan
Hiroshi Morikazu
Nobumori Ogoshi
Koichi Takeyama
DISCO Corporation, 13-11 Omori-Kita 2-chome, Ota-ku, Tokyo 143-8580, Japan
Yoji Wakayama
LINTEC Corporation, 5-14-42 Nishiki-cho, Warabi-shi, Saitama 335-0005, Japan
Tetsuro Obara
Saitama University, 255-Shimo-okubo, Sakura-ku, Saitama-shi, Saitama 338-8570, JapanWe have developed a new laser ablation process using a water-microdrop with a diameter of 70 μm....
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JLA Vol:18 Iss:2 (Laser helical drilling of silicon wafers with ns to fs pulses: Scanning electron microscopy and transmission electron microscopy characterization of drilled through-holes)
Authors:
J. Kaspar
A. Luft
Fraunhofer Institut fu¨r Werkstoff- und Strahltechnik, Winterbergstr.28, D-01277 Dresden, Germany
S. Nolte
M. Will
Institut fu¨r Angewandte Physik, Friedrich-Schiller-Universita¨t, Max-Wien-Platz 1, D-07743 Jena, Germany
E. Beyer
Fraunhofer Institut fu¨r Werkstoff- und Strahltechnik, Winterbergstr.28, D-01277 Dresden, GermanyElectron microscopic methods (scanning electron microscopy and transmission electron microscopy) are used to characterize the precision and quality of microthrough-holes produced in 0.4 mm-thick silicon wafers by applying the pulsed laser helical drill...
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