A novel concept for dual-beam laser lap joining of galvanized steel sheets without intended gap at the interface was recently developed for use in automotive body assembly. Based on the successful demonstration of this novel concept, two prototype heads were designed and built which enabled the realization of this beam configuration through use of a single laser source. Excellent quality welds were obtained with both the twin-head system and the new dual-beam heads on a variety of zinc-coated sheet combinations. In this paper, the fundamental principles are discussed first in order to provide a historical background. Both modeling results and experimental verification at each stage of development are highlighted. The prototype hardware for the two welding heads is briefly illustrated, along with representative weldability results. Finally, preliminary mechanical performance data is presented for welds derived under different conditions, suggesting that fatigue performance is improved for welds without intended gap at the interface. A new dual-beam configuration was proposed based on the fundamental study of the keyhole profile. This configuration uses a backward inclined trailing beam to lap joining zinc-coated steel sheets without intended gap at the interface. This new dual-beam configuration was proved through experiments to be able to improve the welding process robustness, compared to the conventional parallel dual-beam configuration. Based on the theoretical study and experimental proof of the new dual-beam concept, two welding heads were designed and fabricated. The first head, designed for the 4.5-kW power level was tested extensively and proved capable to satisfy the design intent. Good welds were derived on a variety of HDG steel stack-ups and certain GA steel stack-ups. To extend the success achieved from the first welding head, a second welding head was designed and fabricated. This head is intended to be used at higher power, up to 10 kW, for welding at higher speeds and weld thicker stack-ups. Additional adjustability features were built into this high-power head for the purpose of further enhancing its performance. Good weld quality on three layers of HDG steel stack-ups was obtained with this head. Preliminary mechanical testing revealed that the existence of interfacial gap does deteriorate the fatigue performance even though its influence to tensile strength is minor.


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    Titel :

    Development of advanced dual-beam laser welding head for lap joining of zinc-coated steel sheets without intended gap at the interface


    Beteiligte:
    Forrest, Mariana G. (Autor:in) / Lu, Feng (Autor:in)

    Erschienen in:

    Erscheinungsdatum :

    2006


    Format / Umfang :

    11 Seiten, 14 Bilder, 1 Tabelle, 7 Quellen


    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Print


    Sprache :

    Englisch




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