Overcoming the difficulty of gap formation between the conductor junction areas during laser spot micro-welding Available to Purchase

The focus of this paper is to examine the process of laser spot-welding surface mounted devices (SMDs) onto polyisoprene foil (PI-foil) when there is a physical separation between the SMD leads and the PI-foil contact pads. In the experiments performed, the separation distance (gap size) ranged from 0 to 100 µm. The spot welds were made using a pulsed Nd:YAG laser. The parameters examined were primary the pulse shape and the gap size. Furthermore, the total energy delivered and the pulse duration were tested as well in order to improve the results. The quality of the welds were determined by observing the size of the heat affected zone in both the leads and the contact pads as well as the damaged caused to the PI-foil as a result of the welding process. The best results in relation to the weld quality and the boundary conditions were achieved by using a two peaks pulse shape at a pulse energy of 1.9 J and a pulse duration of 4 ms.