Fusion zone behavior in micron-size laser welding Available to Purchase

Lasers are presently employed by industry to make high efficiency, low total heat input welds ranging from ∼0.1 to ∼10mm dimensions. However, with growing emphasis on micro- and nano-scale technologies, we anticipate a need for even smaller welds. Interestingly, at such small sizes calculations suggest that the beam power densities required will result in drilling rather than welding. This work reports attempts at producing laser welds of substantially less than 0.1mm size. We investigate theoretically and experimentally the transitions seen between no melting, conduction- and keyhole-mode melting, and drilling as a function of beam size, intensity and pulse length. A simplified model of the interaction of a high intensity laser beam with the molten zone guided the development of successful welding parameters. We report parameter combinations found to result in successful small spot welds welds in pure Ni, and the values found for transitional behavior to drilling, as well as some unique experimental methods employed.