• JLA Vol:8 Iss:3 (Theoretical and experimental studies of thick‐section cutting with a chemical oxygen–iodine laser (COIL))


    Authors:
    A. Kar
    J. E. Scott
    W. P. Latham



    A simple mathematical model of thick‐section stainless steel cutting with a high power chemical oxygen–iodine laser (COIL) is presented and compared with experimental results obtained with a 10‐kilowatt COIL at the U.S. Air Force's Phillips Laboratory. This model uses a lumped‐parameter technique to relate the cutting kerf depth with various process parameters and can be used to predict scaled laser materials processing performance to very thick sections. The model is similar to an empirical model developed by researchers in Japan, but includes predictive capabilities for thick metal cutting...

    $25.00

  • JLA Vol:18 Iss:1 (Optical viewport assembly for eye-safe monitoring of thin film deposition)


    Authors:
    Kevin Robbie
    Cristina Buzea
    Olivier Landry
    Cory Dean
    Department of Physics, Queen’s University, Kingston, Ontario K7L 3N6, Canada


    This article discusses the design and application of a simple eye-safe monitoring assembly of thin film deposition and its advantages over the existent eye protection filters. This assembly prevents users from being exposed to the radiation field caused by lasers or incandescent objects during thin film deposition. Its design is simple, the device being reliable and easy to operate.

    $25.00

  • JLA Vol:2 Iss:3 (Current State‐of‐the‐Art of Contouring Techniques in Manufacturing)


    Authors:
    Kevin G. Harding
    Industrial Technology Institute, Sensor Center for Improved Quality, Ann Arbor, Michigan 48106


    A manager with a major automobile manufacturer once made the comment that “the best thing we ever did to improve quality was give the guys on the floor a caliper to measure the parts”. As the tolerances on manufacturing become tighter, the need for accurate measurement has also increased. Hand fitting of parts to each other does not work in modern automated factories. Gauges in the past have been built to provide a fixed set of measurements of a known part. This practice too has been changing due to the trend toward flexible manufacturing. Now the gages...

    $25.00

  • JLA Vol:25 Iss:5 (Investigation into the effects of process parameters on bending angle in the laser bending of tailor machined blanks based on a statistical analysis)


    Authors:
    Mehdi Safari
    Mahmoud Farzin
    Abbas Ghaei
    Department of Mechanical Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran


    In this paper, the effects of process parameters on bending angle in laser bending of tailor machined blanks are investigated experimentally. The Taguchi experimental design method is employed to study various parameters, which significantly affect the bending angle in the laser bending of tailor machined blanks. The start point of scan path, irradiating method, laser output power, beam diameter, and number of radiation passes are considered in the evaluations. A L18(21×34) Ta...

    $25.00

  • JLA Vol:24 Iss:4 (Morphology of nanoscale structures on fused silica surfaces from interaction with temporally tailored femtosecond pulses)


    Authors:
    Lars Englert
    Matthias Wollenhaupt
    Cristian Sarpe
    Dirk Otto
    Thomas Baumert
    Institut fuer Physik and CINSaT, Universitaet Kassel, Heinrich-Plett-Str. 40, D-34132 Kassel, Germany


    Laser control of two basic ionization processes on fused silica, i.e., multiphoton ionization and avalanche ionization, with temporally asymmetric pulse envelopes is investigated. Control leads to different final electron densities/energies as the direct temporal intensity profile and the time inverted intensity profile address the two ionization processes in a different fashion. This results in observed different thresholds for material modification o...

    $25.00

  • JLA Vol:16 Iss:2 (Investigation of weld cracking in Nd:yttrium–aluminum–garnet keyhole spot welding of materials used in optoelectronic packaging)


    Authors:
    Geoff J. Shannon
    Unitek Miyachi Corporation, 1820 S. Myrtle Avenue, Monrovia, California 91017

    Bernard Q. Li
    Honeywell VCSEL Optical Division, Minnesota


    The welding of a problematic optical device weld joint between dissimilar materials is investigated in depth. The original material combination of cold rolled steel 1010 with 6 μm of gold coating and 304 L produced consistent weld cracking. The CRS1010 material was fixed, however the other component was open to material selection. The materials tested were 304 L stainless steel, kovar, invar, and Carpenter high permeability 49 alloy. The effect of these different materials, laser pulse parameters, lev...

    $25.00

  • JLA Vol:5 Iss:2 (Experimental Method for Determining the Coherence Length of CW Lasers Using a Michelson Interferometer)


    Authors:
    Sami Alaruri
    Allison Gas Turbine Division, General Motors Corporation, Sensor Development Group


    Theoretical analysis of the relationship between coherence length and the resonant‐longitudinal modes in an optical cavity is given. A Michelson interferometer is used to measure the coherence lengths of two CW He‐Ne laser cavities. Analysis of the experimental measurements shows good agreement with the theoretically predicted values.

    $25.00

  • JLA Vol:20 Iss:4 (Thermal stress analysis on laser scribing of glass)


    Authors:
    Koji Yamamoto
    Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, Japan

    Noboru Hasaka
    Hideki Morita
    Mitsuboshi Diamond Industrial Co., Ltd., 2-12-12 Minami-Kaneden, Suita, Osaka, Japan

    Etsuji Ohmura
    Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, Japan


    In the laser scribing of glass a thermal stress is introduced into a glass substrate by means of a CO2 laser irradiation. The glass substrate is then rapidly cooled down by water jet immediately after the irradiation. For the purpose of theoretical clarification of the factors ruling the scribable condit...

    $25.00

  • JLA Vol:9 Iss:2 (Laser cladding with a pulsed Nd:YAG laser and optical fibers)


    Authors:
    M. Brandt
    D. A. Scott
    S. B. Emms
    J. M. Yellup



    A new laser cladding technique for producing wear and corrosion resistant surfaces on engineering components is reported. The technique involves the combination of the pre‐placed and injected powder delivery methods for producing clad layers. The clad layers were formed with a pulsed Nd:YAG laser and optical fibers. The results using a nickel‐based alloy (Hastelloy C) indicate that uniform clad layers in excess of 1 mm in thickness can be achieved in a single pass with 240 W average power incident on the workpiece. The laser beam was delivered through a step‐index glass ...

    $25.00

  • JLA Vol:17 Iss:1 (Microstructural characterization of dissimilar laser weld between austenitic and ferritic stainless steels)


    Authors:
    Rakesh Kaul
    P. Ganesh
    A. K. Nath
    Industrial CO2 Laser Section, Centre for Advanced Technology, P. O. CAT, Indore 452 013, India


    The present work involved microstructural characterization of thin sheet dissimilar laser welds between type 304 austenitic stainless steel and stabilized 17% Cr ferritic stainless steel and their comparison with welds produced by autogenous gas tungsten arc welding (GTAW). Low heat input of laser welding (LW) effectively reduced the size of fusion zone (FZ) and heat affected zone (HAZ). LW with focused laser beam (LB), preferentially displaced towards austenitic stainless steel (ASS), produced FZ with uniform and highly ref...

    $25.00

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