• JLA Vol:7 Iss:2 (Fraunhofer resource center for laser technology ‐ USA)

    Frank W. Kuepper
    Fraunhofer Resource Center for Laser Technology, Ann Arbor, MI, U.S.A.


  • JLA Vol:7 Iss:2 (Fraunhofer‐Institut fu¨r Lasertechnik)

    Eckhard Beyer
    Fraunhofer‐Institut fu¨r Lasertechnik, Aachen, Germany


  • JLA Vol:7 Iss:2 (Hazardous emissions: characterization of CO<sub>2</sub> laser material processing)

    H. Haferkamp
    M. Goede
    K. Engel
    J.&hyphen;S. Wittbecker
    Laser Zentrum Hannover e.V., Hollerithallee 8, D&hyphen;3000 Hannover 21, Germany

    Parallel to the growth of laser technology is a high interest in safety in industrial surroundings. The characteristics of hazards resulting from laser processing are complex and highly interdependent. In addition, very little fundamental scientific research on this topic exists. The Laser Zentrum Hannover e.V. (LZH) is working on a research project subsidized by the BMFT (German Federal Ministry for Research and Technology) concerning the characterization and reduction of hazardous emissions resulting ...


  • JLA Vol:7 Iss:2 (High&hyphen;speed photographic studies of laser drilling of ceramics and ceramic composites)

    S. Ramanathan
    M. F. Modest
    Department of Mechanical Engineering, The Pennsylvania State University, University Park, PA 16802, U.S.A.

    High&hyphen;speed photographic techniques were used to study plumes generated above a material during drilling of ceramics and ceramic composites with a carbon dioxide laser. The prinicipal objectives were to identify the mechanism of material removal (spattering, particulate and fiber debris, liquid droplets) and plume phenomena (plume shapes and sizes) for ceramics and ceramic composites. High&hyphen;speed photographic (1000 frames per second) visualization of laser drilling was undertaken for two monolithic ceramics, (sintered &...


  • JLA Vol:7 Iss:2 (Laser and optics activities at CREOL)

    C. Martin Stickley
    Center for Research and Education in Optics and Lasers (CREOL), University of Central Florida, Orlando, FL, U.S.A.


  • JLA Vol:7 Iss:2 (Laser processing centers and their research projects in Japan)

    Akira Matsunawa
    Welding Research Institute, Osaka University, 11&hyphen;1 Mihogaoka, Ibaraki, Osaka 567, Japan

    In Japan, R&D activities on laser materials processing are mainly conducted in universities, public research institutions, and technical centers in private enterprise. Among them the Welding Research Institute and the Department of Welding and Production Engineering, both at Osaka University, have taken the initiative in conducting fundamental studies on laser materials processing as well as training experts and engineers in laser technology since the mid 1960s. In 1990, a new laser center called the Applied Laser Engineering Center (ALEC) was established in Naga...


  • JLA Vol:7 Iss:2 (Understanding laser hazard evaluation)

    Wesley J. Marshall
    U.S. Army Center for Health Promotion and Preventive Medicine (Provisional), Aberdeen Proving Ground, MD 21010&hyphen;5422, U.S.A.

    The current 1993 version of the ANSI Z136.1 standard for the safe use of lasers provides maximum permissible exposures which more closely match available biological injury data. Interpreting the standard can be more difficult at times than with previous versions. By keeping the biological injury mechanism in mind, the reasoning behind the multitude of rules contained in the standard are more understandable.


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

    G. L. Goswami
    Dilip Kumar
    A. L. Pappachan
    A. K. Grover
    K. Sridhar

    High&hyphen;chromium ferritic alloys were produced on mild steel substrates by laser surface alloying. For this, chromium&hyphen;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&percnt;, with fairly uniform depth of alloying. Microscopy showed very fine austenite needles within elongated/equiaxed ferrite grains in the laser&hyphen;alloyed zone (LAZ). X&hyphen;ray diffraction indi...


  • JLA Vol:7 Iss:3 (Determination of energy absorption during laser welding by an iterative conduction method)

    Junji Mimatsu
    Jeannine A. Bos
    Elijah Kannatey&hyphen;Asibu
    Michael M. Chen
    Department of Mechanical Engineering and Applied Mechanics, The University of Michigan, 2146 G. G. Brown, Ann Arbor, MI 48109&hyphen;2125, U.S.A.

    Energy absorption is a key process in laser welding. While there is now good qualitative empirical knowledge of the dependence of the effective absorptivity on laser power level, detailed quantitative understanding is poor. In recent years there has been considerable interest in computational modeling of the heat transfer and fluid flow phenomena during laser welding, in order to have a better understanding of the physic...


  • JLA Vol:7 Iss:3 (Impact resistance of adhesive joints using laser&hyphen;induced shock waves)

    I. Gilath
    R. Englman
    Z. Jaeger
    A. Buchman
    H. Dodiuk

    The impact resistance of aluminum–aluminum joint bonded with FM&hyphen;73 (American Cyanamid) structural adhesive was studied using laser&hyphen;induced shock waves. The adhesive joint failed in a ductile mode, showing shock absorbtion ability through plastic deformation. All stages of the impact damage were identified from threshold damage through complete sample perforation. In the theoretical study, the damage induced in the target is obtained as follows. The shock wave is modeled by an expanding stress front, which creates a void population in the laser&hyphen;im...



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