• JLA Vol:24 Iss:2 (Laser dressing of metal bonded diamond blades for cutting of hard brittle materials)


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


    In this study, the authors investigate the laser dressing of metal bonded diamond blades by means of laser pulses with different pulse durations and wavelengths. Conventional dressing suffers from excessive blade wear, whereas laser dressing enables precise removal of the bonding metal to generate the required chip space of protruding diamond grains. The challenge for processing this composite material is to find appropriate level of ablation for the bonding metal without damaging the diamond grains thr...

    $25.00

  • JLA Vol:6 Iss:3 (Safety concerns about laser pointers)


    Authors:
    David H. Sliney
    Jerome E. Dennis



    In the past two years considerable concerns have been expressed about the safety of Class 3A laser pointers. The concern has been that Class 3A diode–laser pointers have replaced the safer helium–neon (He–Ne) Class 2 laser pointers. Hundreds of thousands of small He–Ne visible‐wavelength lasers have been traditionally used for alignment and pointing, laser demonstrations and laser displays in science, education and industry, but can the diode laser be as safe and effective? Not infrequently, some people associate “lasers” with Buck Rogers and “Star Wars”, and are concerned wh...

    $25.00

  • JLA Vol:17 Iss:3 (Laser beam analysis in direct metal deposition process)


    Authors:
    Huan Qi
    Jyoti Mazumder
    Center for Laser Aided Intelligent Manufacturing, Department of Mechanical Engineering, The University of Michigan, Ann Arbor, Michigan 48109

    Larry Green
    Spiricon, Inc., Logan, Utah 84341

    Gary Herrit
    II-VI, Inc., Saxonburg, Pennsylvania 16056


    The quality of a laser beam profile and its stability play fundamental roles in laser material processing. Beam reflections may dramatically affect the beam quality under certain material processing conditions. In this study, experiments were carried out to examine the variations of the continuous wave CO2 laser beam profile during the direct metal...

    $25.00

  • JLA Vol:21 Iss:4 (Contributions of Charles Townes’ research to nonlinear optics)


    Authors:
    Elsa Garmire
    Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA


    Nonlinear optics was profoundly influenced by early work of Charles Townes and his group at Massachusetts Institute of Technology from 1961 to 1967. His foundational contribution was the realization that coherent molecular oscillations resulted from stimulated Raman scattering, leading to the introduction of stimulated Brillouin scattering. Self-trapping of light beams and self-steeping of light pulses in nonlinear materials were two other important innovations. Some applications today of these early ideas are outlined.

    $25.00

  • JLA Vol:8 Iss:3 (Laser Hardened Materials Evaluation Laboratory (LHMEL))


    Authors:
    R. J. Hull
    M. L. Lander



    Since 1976, the Laser Hardened Materials Evaluation Laboratory (LHMEL) has been characterizing material responses to laser energy in support of national defense programs and the aerospace industry. Now that capability is available to commercial industry as well. LHMEL's power levels, beam uniformity, and diagnostics capabilities make it an ideal facility for proof‐of‐concept testing or process development. Located at Wright‐Patterson Air Force Base, Ohio, LHMEL is managed by the Wright Laboratory Materials Directorate and operated by Lawrence Associates, Incorporated. The facility's advanced hardware is centered aroun...

    $25.00

  • JLA Vol:2 Iss:2 (Binary Phase Gratings for Materials Processing)


    Authors:
    Paul J. Patt
    Array


    The feasibility of using a diffractive optical element, a phase grating, as a beam handling device for use in industrial laser material processing is examined. The binary phase grating is an efficient beam splitting device and is useful in many materials processing operations (welding, cutting, soldering, drilling) where a high degree of parallelism could significantly improve process throughput. Overall efficiency of etched quartz binary gratings agrees well with published predictions (nominal 70–90%). Copies of the grating formed in PMMA (acrylic) survived preliminary life tests (more than 1000 9‐J pulses from a commercial multimode N...

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  • JLA Vol:15 Iss:4 (Welding of thick austenitic stainless steel using Nd:yttrium–aluminum–garnet laser with filler wire and hybrid process)


    Authors:
    Tommi Jokinen
    Miikka Karhu
    VTT Industrial Systems, P.O. Box 17021, FIN 53851 Lappeenranta, Finland

    Veli Kujanpa¨a¨
    Lappeenranta University of Technology, P.O. Box 20, FIN 53851 Lappeenranta, Finland


    Autogenous laser welding has shown many advantages over traditional welding methods in numerous applications. However, there could be even more applications, but due to the power levels of present high power lasers, depth of penetration is limited. One way to overcome this limitation is to use multipass laser welding, in which a narrow gap and a filler wire are applied. By this process thick sections can be welded with a smaller heat inpu...

    $25.00

  • JLA Vol:25 Iss:5 (Heat transfer and fluid flow in additive manufacturing)


    Authors:
    A. Raghavan
    H. L. Wei
    T. A. Palmer
    T. DebRoy
    Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802


    In laser-based direct energy deposition additive manufacturing, process control can be achieved through a closed loop control system in which thermal sensing of the melt pool surface is used to adjust laser processing parameters to maintain a constant surface geometry. Although this process control technique takes advantage of important in-process information, the conclusions drawn about the final solidification structure and mechanical properties of the deposited material are li...

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  • JLA Vol:19 Iss:4 (Experimental observation of keyhole shapes in the laser welding of aluminum blanks)


    Authors:
    B. J. Aalderink
    Netherlands Institute for Metals Research, P.O. Box 217, 7500 AE Enschede, The Netherlands

    R. G. K. M. Aarts
    University of Twente, Laboratory of Mechanical Automation, P.O. Box 217, 7500 AE Enschede, The Netherlands

    D. F. de Lange
    Netherlands Institute for Metals Research, P.O. Box 217, 7500 AE Enschede, The Netherlands

    J. Meijer
    University of Twente, Laboratory of Mechanical Automation, P.O. Box 217, 7500 AE Enschede, The Netherlands


    A camera-based in situ monitoring system for the Nd:yttrium–aluminum–garnet laser keyhole welding process of aluminium has been developed. The...

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  • JLA Vol:24 Iss:4 (Laser-assisted nanofabrication of carbon nanostructures)


    Authors:
    Yun Shen Zhou
    Wei Xiong
    Jongbok Park
    Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0511, USA

    Min Qian
    Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska, 68588-0511, USA and Department of Physics, East China Normal University, Shanghai 200062, People’s Republic of China

    Masoud Mahjouri-Samani
    Yang Gao
    Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0511, USA

    Lan Jiang
    Department of Mechanical and Automation Engineering, Beijing Institute of Technology, Bei...

    $25.00

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