• JLA Vol:15 Iss:4 (Induction heat treatment of laser welds)


    Authors:
    Claus Bagger
    Joakim Ilsing Sørensen
    Flemming O. Olsen
    Manufacturing Engineering and Management, Materials and Process Technology, Technical University of Denmark, Building 425, DK-2800 Lyngby, Denmark


    In this article, a new approach based on induction heat treatment of flat laser welded sheets is presented. With this new concept, the ductility of high strength steels GA260 with a thickness of 1.8 mm and CMn with a thickness of 2.13 mm is believed to be improved by prolonging the cooling time from 750 to 450 °C. Initially, a simple analytical model was used to calculate the ideal energy contributions from a CO2 high power laser s...

    $25.00

  • JLA Vol:19 Iss:4 (Ablation and cutting of silicon wafer and micro-mold fabrication using femtosecond laser pulses)


    Authors:
    Ying Wang
    Nengli Dai
    Yuhua Li
    Xinlin Wang
    Peixiang Lu
    Wuhan National Laboratory for Optoelectronics and School of Optoelectronics Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China


    Femtosecond laser micromachining of silicon wafer at a relatively higher energy fluence level (>50 J/cm2) is investigated. Laser ablating spots and cutting kerfs are examined by means of charge coupled device camera and scanning electron microscopy. The area of ablated spots increases linearly with increasing the shot number from 1 to 16 and shows saturation with t...

    $25.00

  • JLA Vol:24 Iss:4 (Femtosecond laser-induced periodic surface structures)


    Authors:
    J. Bonse
    J. Kru¨ger
    S. Ho¨hm
    A. Rosenfeld
    Array


    The formation of laser-induced periodic surface structures (LIPSS) in different materials (metals, semiconductors, and dielectrics) upon irradiation with linearly polarized fs-laser pulses (τ ∼ 30–150 fs, λ ∼ 800 nm) in air environment is studied experimentally and theoretically. In metals, predominantly low-spatial-frequency-LIPSS with periods close to the laser wavelength λ are observed perpendicular to the polarization. Under specific irradiation conditions, high-spatial-frequency-LIPSS with sub-100-nm spatial periods (∼λ/10) can be gene...

    $25.00

  • JLA Vol:5 Iss:1 (Single Pass Laser Cutting of Polymers)


    Authors:
    R. Patel
    G. Baisch
    IBM Corporation, GTD, Hopewell Junction, New York


    Since the early 1980's discovery of the ability of excimer lasers to etch polymers precisely and cleanly with minimal thermal damage, excimer lasers have been used actively in the semiconductor industry for various manufacturing processes. In the present study a process for laser cutting of polymers has been investigated. A laser beam of controlled cross‐sectional shape is imaged onto a polymer surface. The geometry of the cutting path is controlled by precise movement of a sample mounted on a 2‐axis computer controlled work stage. This type of a process is useful for applications ...

    $25.00

  • JLA Vol:25 Iss:5 (Numerical and experimental study of the effect of groove on plasma plume during high power laser welding)


    Authors:
    Cai Yan
    Xie Wen-Jing
    Wu Yue
    Sun Da-Wei
    Wu Yixiong
    Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240, China and Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai 200240, China


    The influence of groove on the static feature and dynamic behavior of plasma plume during high power CO2 laser welding process was studied using a hydrodynamic three-dimensional model and corresponding experiments. The temperature, composition, and velocity of plasma plume along the incident path of laser beam were computed. The static morphology of plasma plume was analyzed through both models ...

    $25.00

  • JLA Vol:14 Iss:1 (Multiple reflection and its influence on keyhole evolution)


    Authors:
    Hyungson Ki
    Pravansu S. Mohanty
    Jyotirmoy Mazumder
    Center for Laser Aided Intelligent Manufacturing, Department of Mechanical Engineering and Applied Mechanics, The University of Michigan, Ann Arbor, Michigan 48109-2125


    In laser drilling and keyhole welding, multiple reflection phenomena determine how the energy is transferred from the laser beam to the workpiece, and, most importantly, all other physics such as fluid flow, heat transfer, and the cavity shape itself depend on these phenomena. In this study, a multiple reflection model inside a self-consistent (or self-evolving) cavity has been developed based on the level set method and ray tracing t...

    $25.00

  • JLA Vol:18 Iss:2 (Laser ablation of silicon wafer with a water microdrop)


    Authors:
    Kouki Shimizu
    Kunimitsu Takahashi
    Photonics and Materials Research Department, Institute of Research and Innovation, 1201 Takada, Kashiwa, Chiba 277-0861, Japan

    Hiroshi Morikazu
    Nobumori Ogoshi
    Koichi Takeyama
    DISCO Corporation, 13-11 Omori-Kita 2-chome, Ota-ku, Tokyo 143-8580, Japan

    Yoji Wakayama
    LINTEC Corporation, 5-14-42 Nishiki-cho, Warabi-shi, Saitama 335-0005, Japan

    Tetsuro Obara
    Saitama University, 255-Shimo-okubo, Sakura-ku, Saitama-shi, Saitama 338-8570, Japan


    We have developed a new laser ablation process using a water-microdrop with a diameter of 70 μm....

    $25.00

  • JLA Vol:22 Iss:4 (Effect of laser and laser hybrid welding on the corrosion performance of a lean duplex stainless steel)


    Authors:
    Elin M. Westin
    Outokumpu Stainless AB, Avesta Research Center, P.O. Box 74, 774 22 Avesta, Sweden

    Anna Fellman
    Laser Processing Laboratory, Lappeenranta University of Technology, Tuotantokatu 2, 53850 Lappeenranta, Finland


    The use of duplex stainless steel increases steadily worldwide and the fluctuations in nickel price the recent years have contributed to further growth. The lean duplex grade Outokumpu LDX 2101® (EN 1.4162, UNS S32101) has a low nickel content and is alloyed with nitrogen and manganese to give a balanced microstructure. It means that good austenite formation is obtained even when laser welding autogenously (without fille...

    $25.00

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


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


    $25.00

  • JLA Vol:1 Iss:3 (Laser Welding of Plastics in Low and High Gravity Environments)


    Authors:
    R. E. Mueller
    W. W. Duley
    CRESS and Laser Processing Laboratory, York University, Toronto, Ontario, Canada M3J 1P3

    S. MacLean
    M. Garneau
    B. Tryggvason
    Canadian Astronaut Office, National Research Council, Ottawa, Ontario, Canada K1A 0R6

    W. F. J. Evans
    Atmospheric Environment Service, 4905 Dufferin Street, Downsview, Ontario M3H 5T4


    Initial results of a series of laser processing experiments performed under the micro‐gravity conditions supplied by NASA's KC‐135 aircraft are presented. Weld morphologies of polypropylene and polyethylene were obtained under both hyper‐ and hy...

    $25.00

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