Characterization of absorptivity in micro-welding of copper by pulsed green Nd:YAG laser Available to Purchase

The absorptivity to copper depended on the laser wavelength and welding mode, and absorptivity at 532nm was five times higher than that at 1064nm under no-melting condition. Absorptivity decreased with increasing penetration depth in the case of heat conduction welding, while absorptivity increased with increasing penetration depth in the case of key-hole welding. Deep penetration with the keyhole could be performed by a pulsed green Nd:YAG laser, while fundamental wavelength of Nd:YAG laser would result in almost no-melting even under the same condition. It was cleared that the effect of weld bead geometry was large, and the control of pulse waveform was effective for stable machining. The pulse waveform with maximum peak at the early period and a long pulse duration led to good results stabilizing the penetration depth with less porosity.