• JLA Vol:16 Iss:1 (Laser-assisted chemical cleaning for oxide-scale removal from carbon steel surfaces)

    Hyunkyu Lim
    Dongsik Kim
    Department of Mechanical Engineering, POSTECH, Pohang 790-784, Korea

    The article introduces a novel laser chemical processing technique for removing thin oxide layers on low-carbon steel surfaces by combining laser-induced shock waves and the chemical cleaning technique that is currently utilized in the conventional oxide-scale removal. A Q-switched Nd:yttritium–aluminum–garnet laser (wavelength 1064 nm, full width at half maximum 6 ns) induces optical breakdown in the acid solution, producing intense pressure waves which act as a noncontact scale breaker. It has been demonstrated that the novel process leads to substa...


  • JLA Vol:16 Iss:1 (Laser-induced electrochemical characteristics of aluminum alloy 2024-T3)

    Olga Kachurina
    Tammy L. Metroke
    Kai Dou
    Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078

    Laser-induced surface modification of aluminum alloy 2024-T3 was investigated as laser intensity dependence of surface composition and patterning related to electrochemical characteristics using techniques of environmental scanning electron microscopy (ESEM), potentiodynamic scan, and electrochemical impedance spectroscopy (EIS). Analysis of surface composition using ESEM and EIS indicated that laser fluences in a range of 1.1–1.3 J/cm2 were found to preferentially reduce the copper concentration in the alloy surf...


  • 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:16 Iss:1 (Nd:yttritium–aluminum–garnet laser welding of copper to stainless steel)

    Hongwei Shen
    Mool C. Gupta
    Applied Research Center, College of Engineering and Technology, Old Dominion University, Newport News, Virginia 23606

    Systematic laser welding experiments were conducted on dissimilar metal of copper and 300 series stainless steel using a high average power Lumonics JK 701H Nd:yttritium–aluminum–garnet laser. The laser melt penetration depth and width in copper and stainless steel were evaluated as a function of the laser parameters. The results reveal that melting of copper demands much higher average power, shorter pulse duration, and lower welding speed than melting stainless steel. If the laser beam is focused on the int...


  • JLA Vol:16 Iss:1 (Physics, chemistry, and laser microprocessing)

    W. W. Duley
    Physics Department, University of Waterloo, Waterloo ON N2L 3G1, Ontario, Canada

    This article discusses some basic concepts of laser processing when individual components have micron and submicron dimensions. Since joining and parting operations involve bond formation and bond breaking between atoms, the energy terms involved are quite similar in micro- and macroapplications. In fact, several elements of laser cutting and welding can be found in the laser-induced photochemical reactions of atoms and molecules. It is shown that there are no intrinsic wavelength limitations in laser processing of microsystems, as the scale length for processing is set by the dimensi...


  • JLA Vol:16 Iss:1 (Plume attenuation under high power Nd:yttritium–aluminum–garnet laser welding)

    J. Greses
    Engineering Department, University of Cambridge, Cambridge, CB2 1RX United Kingdom

    P. A. Hilton
    TWI, Granta Park, Abington, Cambridge, CB1 6AL United Kingdom

    C. Y. Barlow
    Engineering Department, University of Cambridge, Cambridge, CB2 1RX United Kingdom

    W. M. Steen
    Laser Group, University of Liverpool, Liverpool, L69 3GH United Kingdom

    During high-power continuous wave (cw) Nd:yttritium–aluminum–garnet (YAG) laser welding a vapor plume is formed containing vaporized material ejected from the keyhole. The gas used as a plume control mechanism affects the plume shape but not its temperature,...


  • JLA Vol:16 Iss:2 (Effects of irradiated conditions of Er:yttritium–aluminum–garnet laser on tooth vibration)

    Kazunori Takamori
    Shigeru Watanabe
    Department of Pediatric Dentistry, Meikai University School of Dentistry

    Clinical studies that the Er:yttritium–aluminum–garnet (YAG) laser cause less pain in cutting. Unlike high-speed drilling Er:YAG laser irradiation does not cause pain by vibration, pressure, heat, or noise. We suspected that the greatest difference in characteristics between the Er:YAG laser and the high-speed drill is the amount of tooth vibration during cavity preparation. It will be simultaneously pain or discomfort during tooth cutting. Previously, the authors revealed that increased vibration speed was observed with an increase in Er:YAG la...


  • JLA Vol:16 Iss:2 (Foam coating on aluminum alloy with laser cladding)

    V. Ocelı´k
    V. van Heeswijk
    J. Th. M. De Hosson
    Department of Applied Physics, Material Science Center and The Netherlands Institute for Metals Research, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands

    K. Csach
    Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 043 53 Košice, Slovakia

    This article concentrates on the creation of a foam layer on an Al–Si substrate with laser technology. The cladding of Al–Si powder in the front of a laser track has been separated from the side injection of mixture of Al–Si/TiH2 powder (foaming agent),...


  • JLA Vol:16 Iss:2 (High-power CO<sub>2</sub> laser design &ldquo;from resonator end mirror to cutting lens focal point&rdquo;)

    David Toebaert
    HACO NV, Oekenestraat 120, 8800 Rumbeke, Belgium

    Wybo Wagenaar
    Infinite Simulation Systems BV, Lange Bunder 3, 4854 MB Bavel, Netherlands

    An algorithm is derived that allows calculating all optical parameters relevant to the design of a high-power CO2 laser, taking into account the practical needs of a flying-optics type of laser cutting machine. The novelty of the approach taken is that the resonator and the beam delivery optics are treated simultaneously, which allows for greater flexibility in design. To begin with, the often-used optical configuration of a stable resonator combined with a beam expander for collimation is mod...


  • JLA Vol:16 Iss:2 (In-process monitoring and feedback control during laser microspot lap welding of copper sheets)

    Yousuke Kawahito
    Production Core Engineering Laboratory, Corporate Production Engineering Division, Matsushita Electric Industrial Co., Ltd., 2-7 Matsuba-cho, Kadoma, Osaka 571-8502, Japan

    Seiji Katayama
    Joining and Welding Research Institute (JWRI), Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan

    The establishment of laser welding of copper sheets, as an electronics manufacturing process is anticipated. This study was performed with an objective of stably and consistently producing fully penetrated lap welds in two copper sheets of 0.1 mm thickness. A new procedure for in-process monitoring and feedback control was developed for microsp...



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