• JLA Vol:19 Iss:3 (Gas investigation for laser drilling)

    Matthieu Schneider
    GIP GERAILP,16 bis Avenue Prieur de la Coˆte d’Or 94114 Arcueil Cedex, France

    Laurent Berthe
    Re´my Fabbro
    Maryse Muller
    Mariette Nivard
    Laboratoire pour l’Application des Lasers de Puissance (UPR CNRS no 1578), 16 bis Avenue Prieur de la Coˆte d’Or 94114 Arcueil Cedex, France

    This article deals with the gas effect on percussion laser drilling in ms pulse duration range. On the one hand, the flow of assistance gas jet is investigated with and without a target using a strioscopy setup and Pitot’s tube. By this way, the position of shock waves in the supersonic...


  • JLA Vol:24 Iss:5 (<em>Quo vadis</em>, laser additive manufacturing?)

    Ingomar Kelbassa
    Fraunhofer Institute for Laser Technology ILT, Steinbachstrasse 15, 52074 Aachen, Germany and Chair for Laser Technology LLT, RWTH Aachen University, Steinbachstrasse 15, 52074 Aachen, Germany

    Terry Wohlers
    Tim Caffrey
    Wohlers Associates, Inc., OakRidge Business Park, 1511 River Oak Drive, Fort Collins, Colorado 80525


  • JLA Vol:8 Iss:6 (Teaching laser principles with nitrogen laser pumped dye lasers)

    David H. Lieberman
    Physics Department, Queensborough Community College, 222&hyphen;05 56th Ave., Bayside, NY 11364&hyphen;1497, U.S.A.

    Nitrogen laser pumped dye lasers are useful aids to the understanding of the principles of lasers and also as tools for advanced undergraduate physics and chemistry laboratories. We have developed laboratory exercises that allow the students to develop necessary skills and study important principles. The students construct their own narrow linewidth dye lasers in a step&hyphen;by&hyphen;step process. First amplified spontaneous emission is studied and compared with broadband lasing. A grating is added to provide linewidth narrowing and tunabil...


  • JLA Vol:18 Iss:1 (Pulsed laser welding of metal-polymer sandwich materials using pulse shaping)

    H. L. Gower
    R. R. G. M. Pieters
    I. M. Richardson
    Netherlands Institute for Metals Research, Rotterdamseweg 137 2628 AL Delft, The Netherlands

    Increasing interest has been expressed in the application of hybrid metal/polymer materials for automotive applications, both to reduce weight and to improve performance. To date, the only joining methods available are mechanical fastening and adhesive bonding, both requiring an overlapping joint configuration to generate sufficient bond strength. This article describes how laser spot-welding and SHADOW™ (stepless high speed accurate and discrete one pulse welding) welding can be used to minimize degradat...


  • JLA Vol:9 Iss:1 (On the formation of the keyhole and its temperatures)

    E. A. Metzbower
    US Naval Research Laboratory, Code 6320, Washington, DC 20375&hyphen;5000, U.S.A.

    A thermodynamically based model has been developed to calculate the size and temperature of the ‘keyhole’ through the thickness of the weldment. The model is based on calculating the power loss resulting from evaporation of an element in the chemistry of the plate and a minimum power density required to produce a keyhole. The evaporative power loss is set equal to the Gaussian power density, which is used to represent the laser beam. The result is a temperature distribution across the keyhole. Absorption of the laser power in the keyhole is calculated based on inverse...


  • JLA Vol:4 Iss:3 (Using the Proposed ANSI Z136.1&hyphen;1992 Standard)

    R. James Rockwell
    Rockwell Laser Industries


  • JLA Vol:16 Iss:1 (Metallic vapor ejection effect on melt pool dynamics in deep penetration laser welding)

    Re´my Fabbro
    Mohammed Hamadou
    Frederic Coste
    CLFA (Coope´ration Laser Franco-Allemande), 16 bis, Avenue Prieur de la Côte d’Or, 94114 Arcueil Cedex, France

    The hydrodynamics phenomena involved during the laser welding process are very complex. Among the possible involved mechanisms controlling the hydrodynamics of the weld pool, it is well known that the melt displacement resulting of the local pressure applied to the liquid surface as a result of the evaporation process, plays an important role. We would like to show in this article that, using specific experiments based on twin or triple spot interaction geometry, the fricti...


  • JLA Vol:20 Iss:2 (Connection of macro-sized double-walled carbon nanotube strands by current-assisted laser irradiation)

    Tao Gong
    Yong Zhang
    Wenjin Liu
    Jinquan Wei
    Kunlin Wang
    Dehai Wu
    Minlin Zhong
    Key Laboratory for Advanced Materials Processing Ministry of Education, Department of Mechanical Engineering, Tsinghua University, Beijing, 100084, China

    Macro-sized (centimeters long) double-walled carbon nanotube (DWNT) strands were connected by current-assisted laser irradiation after bandaging their overlapped ends with DWNT films. During the laser processing, structural transformation of DWNT bundles happened at the joints, which provided molecular bonding between the strands. Tensile tests indicate that the joints mad...


  • JLA Vol:25 Iss:3 (Weldability and keyhole behavior of Zn-coated steel in remote welding using disk laser with scanner head)

    Su-Jin Lee
    Seiji Katayama
    Yousuke Kawahito
    Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan

    Keisuke Kinoshita
    Vehicle Production Engineering Division, Nissan Motor Co., Ltd., 560-2 Okatsukoku, Atsugi-shi, Kanagawa 243-0192, Japan

    Jong-Do Kim
    Division of Marine Engineering, Korea Maritime University, Yeongdo-gu, Busan 606-791, South Korea

    Zinc-coated steels are widely used in automobile bodies. Laser welding, which offers a lot of advantages over the conventional welding with metal active gas welding, CO2 arc, etc. in terms of improved weld q...


  • JLA Vol:23 Iss:2 (Comprehensive predictive modeling and parametric analysis of multitrack direct laser deposition processes)

    Shaoyi Wen
    Yung C. Shin
    Center for Laser-Based Manufacturing, School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907

    Direct laser deposition is a very useful method of fabricating complex parts directly from CAD drawings. Despite its usefulness, many parameters that affect the final quality of the fabricated part make the selection of optimal operating conditions difficult. In this paper, new comprehensive numerical modeling is presented to describe the underlying physics in multitrack direct laser deposition processes including laser powder interaction, mass addition, fluid motion, melting, and solidification. The model rigorously con...



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