Wetting of different lead free solder alloys during vapour phase soldering

In this paper the wetting properties of lead free solder alloys were investigated on different printed circuit boards (PCB) during Vapour Phase Soldering (VPS), which is an alternative reflow method with non-conventional heat-transfer mechanism. Our motivation was to investigate the phenomenon on PCBs with different thermal capacities, with different heating power and with different solder alloys. The aim of the research is to clear the relations between the thermal capacities of the) PCBs and the spreading of the solder on it, and to investigate the effect of the change of heating power on the solder spreading during VPS. In addition, the impact of the VPS on different solder alloys and the performance of the VPS machine in the wake of the contact angle quality was investigated. Findings show that the thickness of the PCB is not affecting significantly the spread and the wetting. The composition of the alloy, the paste, and the heating power points to observable differences in the final result