• JLA Vol:26 Iss:1 (Performance enhancement of aluminum infrared laser welding by preconditioning with nanosecond laser pulses)


    Authors:
    Philipp von Witzendorff
    Anas Moalem
    Uwe Stute
    Ludger Overmeyer
    Laser Zentrum Hannover e.V., Hollerithallee 8, 30419 Hannover, Germany


    We condition the welding zone of the aluminum surface with nanosecond laser pulses prior to welding with infrared laser radiation to increase the process efficiency and weld quality. The high reflectivity of aluminum for infrared laser radiation (95% at 1064 nm) leads to poor process efficiency of aluminum laser welding processes. To increase the workpiece's absorptivity, the welding zone is conditioned with nanosecond laser pulses at a wavelength of 532 nm. The samples are nonalloy, 0.5 mm thick alum...

    $25.00

  • JLA Vol:15 Iss:4 (Laser–material interaction and process sensing in underwater Nd:yttrium–aluminum–garnet laser welding)


    Authors:
    Xudong Zhang
    Wuzhu Chen
    Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China

    Eiji Ashida
    Fukuhisa Matsuda
    Tarasaki R&D Center, JAPEIC, Hitachinaka, Ibaraki 312-0003, Japan


    Laser–material interaction and process sensing technology for local-dry underwater Nd:yttrium–aluminum–garnet laser beam welding were studied. The optical emissions induced by laser–water interaction were detected with an infrared (IR) optical sensor and observed with a charge coupled device camera. It was found that under laser irradiation, a kind of water–vapor plasma formed immediately above the ...

    $25.00

  • JLA Vol:20 Iss:1 (Practical and theoretical investigations into inert gas cutting of 304 stainless steel using a high brightness fiber laser)


    Authors:
    Martin Sparkes
    Markus Gross
    Steven Celotto
    Tao Zhang
    William O’Neill
    Centre for Industrial Photonics, Institute for Manufacturing, Department of Engineering, University of Cambridge, Cambridge, CB2 1RX, United Kingdom


    A 2.2 kW fiber laser was used in a series of inert cutting trials on stainless steels of section thicknesses in the range of 6–10 mm. Variations in the cutting performance with changing gas pressure, focal position, and nozzle diameter were investigated. Results showed the difficulties associated in cutting with high brightness lasers, specifically in obtaining full melt eject through narr...

    $25.00

  • JLA Vol:24 Iss:4 (Cellular reactions toward nanostructured silicon surfaces created by laser ablation)


    Authors:
    K. Wallat
    Institute of Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Universitaetsstr. 5-7, 45117 Essen, Germany

    D. Do¨rr
    R. Le Harzic
    F. Stracke
    D. Sauer
    Fraunhofer Institute for Biomedical Engineering (IBMT) and Chair for Molecular and Cellular Biotechnology (University of Saarbruecken), Ensheimer Str. 48, 66386 St. Ingbert, Germany

    M. Neumeier
    A. Kovtun
    Institute of Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Universitaetsstr. 5-7, 45117 Essen, Germany

    H. Zimm...

    $25.00

  • JLA Vol:4 Iss:3 (Recommendations for Safe and Appropriate Use of Lasers in Dentistry in Face of Rising Concerns)


    Authors:
    Leo J. Miserendino
    Elliot Abt
    David Harris
    Harvey Wigdor
    The Chicago Dental Laser Institute


    $25.00

  • JLA Vol:1 Iss:2 (Summary of Laser Plume Effects and Safety Session)


    Authors:
    Richard P. Felten
    Senior Chemist, Radiation Biology Branch, Center for Devices and Radiological Health, Food and Drug Administration


    $25.00

  • JLA Vol:14 Iss:2 (Human behavioral factors in laser safety)


    Authors:
    Rick Mannix
    Environmental Health & Safety Office, University of California, Irvine, California 92697-2725


    While training, engineering controls, warning signs/systems, and protective eyewear are emphasized in laser safety programs, laser-related accidents do occur in facilities without obvious deficiencies in those areas. Problems still occur because of insufficient attention to administrative safety issues directly related to human nature and behavioral factors. Common safety problems associated with behavioral factors are discussed. Personal experiences of the author, including lessons learned, are included. The issues are discussed within the context of laser safety, bu...

    $25.00

  • 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), Italy


    The 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 ...

    $25.00

  • JLA Vol:23 Iss:1 (Review of laser microscale processing of silicon carbide)


    Authors:
    B. Pecholt
    S. Gupta
    P. Molian
    Department of Mechanical Engineering, Laboratory for Lasers, MEMS and Nanotechnology, Iowa State University, Ames, Iowa 50011


    A review of various laser techniques for microscale processing of SiC for microelectronics and microelectromechanical-system applications is presented. SiC is an excellent material for harsh environments due to its outstanding mechanical, thermal, and chemical properties. However, its extreme thermodynamic stability and inert properties created difficulties in conventional microfabrication methods which provided an opportunity for the exploration of laser processing as an alternative. Many aspects...

    $25.00

  • JLA Vol:7 Iss:3 (Characterization of chromium bearing surface alloys produced by laser alloying on low carbon steel substrates)


    Authors:
    G. L. Goswami
    Dilip Kumar
    A. L. Pappachan
    A. K. Grover
    K. Sridhar
    Array


    High‐chromium ferritic alloys were produced on mild steel substrates by laser surface alloying. For this, chromium‐plated mild steel samples were treated with a pulsed Nd:YAG laser (300 W maximum power) by varying the average power level from 21.6 W to 30.0 W. The chromium content of the surface alloys was in the range of 3.0–27.0 wt%, with fairly uniform depth of alloying. Microscopy showed very fine austenite needles within elongated/equiaxed ferrite grains in the laser‐alloyed zone (LAZ). X‐ray diffraction indi...

    $25.00

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