• JLA Vol:2 Iss:1 (The Energy Transfer Efficiency in Laser Welding Process)

    T. H. Kim
    Charles E. Albright
    Schichan Chiang
    Department of Welding Engineering, The Ohio State University, 190 W. 19th Ave., Columbus, Ohio 43210

    The process efficiency of laser beam welding was measured as a function of travel speed. Temperature measurements were carried out during the bead‐on‐plate laser welding of mild steel with a focused 2KW CO2 laser beam at various welding travel speeds. The laser welding process efficiency (power delivered to work/power in the beam) was calculated from the ratio of the heat content of the welded the specimen to the available laser beam energy (power × time). In the deep penetr...


  • JLA Vol:15 Iss:4 (Solution of two-temperature thermal diffusion model of laser–metal interactions)

    S. R. Vatsya
    Kuljit S. Virk
    Integrated Manufacturing Technologies Institute, National Research Council of Canada, 800 Collip Circle, London, Ontario N6G 4X8, Canada

    The two temperature coupled equations, modeling thermal diffusion during laser-induced ablation of metals, are solved under the assumptions that the electron and the lattice heat capacities, and the thermal conductivity remain constant in the process. In view of its practical value, the solution is initially obtained for the energy sources with a Gaussian distribution. The solution is then generalized to include a larger class of source terms for comparison with other results. Present analysis is vali...


  • JLA Vol:20 Iss:1 (Experimental investigation of remote welding with CO<sub>2</sub> and Nd:YAG laser-based systems)

    George Tsoukantas
    Aristidis Stournaras
    George Chryssolouris
    Laboratory for Manufacturing Systems and Automation, Department of Mechanical Engineering and Aeronautics, University of Patras, Patras 265 00, Greece

    Remote welding provides new possibilities for highly productive and flexible joining of metal structures, especially in the automotive industry. This study presents an experimental investigation on the behavior of the lap welds’ geometrical characteristics with respect to the laser beam inclination. Two remote welding systems (RWSs) have been utilized: a large field RWS with a CO2 laser and a small field RWS with an Nd:YAG las...


  • JLA Vol:25 Iss:3 (Surface pore initiated fatigue failure in laser clad components)

    M. M. Alam
    J. Powell
    A. F. H. Kaplan
    Department of Engineering Science and Mathematics, Luleå University of Technology, SE-971 87 Luleå, Sweden

    J. Tuominen
    P. Vuoristo
    Department of Materials Science, Tampere University of Technology, FI-33101 Tampere, Finland

    J. Miettinen
    J. Poutala
    Department of Mechanics and Design, Tampere University of Technology, FI-33101 Tampere, Finland

    J. Na¨kki
    Department of Materials Science, Tampere University of Technology, FI-33101 Tampere, Finland and Technology Centre KETEK Ltd, FI-67100 Kokkola, Finland

    J. Junkala


  • JLA Vol:24 Iss:4 (Structural study of near-field ablation close to plasmon-resonant nanotriangles)

    Andreas Kolloch
    Paul Leiderer
    Department of Physics, University of Konstanz, Universita¨tsstr. 10, D-78457 Konstanz, Germany

    Shyjumon Ibrahimkutty
    Daniel Issenmann
    Anton Plech
    Institute for Synchrotron Radiation, Karlsruhe Institute of Technology, Postfach 3640, D-76021 Karlsruhe, Germany

    The optical near fields in close vicinity to plasmonic nanoscale objects show a considerable enhancement of the electrical field and are localized to dimensions much less than the wavelength of light. The authors show that an ablation process caused by the near-field enhancement of femtosecond laser pulses pattern the substrate...


  • JLA Vol:14 Iss:2 (Development of simulated pigmented lesions in an optical skin-tissue phantom: Experimental measurements in the visible and near infrared)

    Manuela Lualdi
    Ambrogio Colombo
    Alberto Mari
    Stefano Tomatis
    Renato Marchesini
    Medical Physics Unit, Istituto Nazionale per lo Studio e la Cura dei Tumori, Milan, Italy

    Realistic, pigmented skin simulants (“phantoms”) can be useful in optimizing dermal laser procedures and for laser surgical training. Diffuse reflectance of skin pigmented lesions depends on the amount and distribution of the absorbing/diffusing chromophores, mainly hemoglobin and melanin, embedded in the skin layers. The reason why diffuse reflectance of benign melanocytic lesions is different from that of melanoma is still unclear. In an attempt...


  • JLA Vol:18 Iss:3 (The influence of joint gap on the strength of hybrid Nd:yttrium-aluminum-garnet laser-metal inert gas welds)

    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, Sweden

    This 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. ...


  • JLA Vol:23 Iss:1 (Picosecond laser-induced color centers in glass optics)

    David Ashkenasi
    Andreas Lemke
    Applied Laser Technology, Laser- and Medical-Technology Berlin (LMTB) GmbH, Fabeckstr. 60-62, 14195 Berlin, Germany

    It is known that ionizing radiation (x ray, gamma rays, and electrons) can induce numerous changes in the physical properties of glasses. The most obvious effect is visible coloration, which is caused by the accumulation of color centers (defects) in the irradiated volume. The application of such induced color centers has prompted a renewed interest since they can be generated and bleached reversibly. We present results on laser-induced color centers in different types of glasses using picosecond laser pulses. By applyi...


  • JLA Vol:7 Iss:3 (Study of liquid and vapor ejection processes during laser drilling of metals)

    Bekir S. Yilbas¸
    Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia

    In an experimental investigation of laser–metal interaction, one of the important parameters is the propagation velocity of the liquid–vapor interface. The quantity appears as a direct result of the theoretical examination of the interaction and may be used to test the accuracy of the theory. Consequently, in the present study, the nature of the interaction mechanism between a pulsed laser beam and metals is examined using streak photographs of the ejecta from four metals: titanium, tantalum, nickel, and EN58B stainless steel. It...



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