Study of the components self-alignment in surface mount technology

The operator or pick and place machine sometimes place the component on its position with a small shift. It isn't a critical mistake, because it is a well known phenomenon that during the time when the solder paste is in liquid state the wetting force that acts on components shifts the component to the correct (straight) position according to the soldering pads. This article deals with study of SMD components self-alignment in surface mount technology. In this article, the component self-alignment with regard to different types of solders, different types of reflow technology, different solder paste volume and different component placement angles was observed. In our experiments three types of solders - one leaded (Sn62/Pb36/Ag2) and two lead-free (Sn99,25/Cu0,7/Ni0,05 and Sn95,5/Ag4/Cu0,5) and two types of reflow technologies (hot air soldering and vapor phase soldering) were used.