Relationship between the printing shape and the fillet shape

The following are examples where the fillet shape changes depending on the printing shape.

Example shows the comparison of fillet shape differences by creating the mask opening so that printing fading is inside the land at IC116 and outside the land at IC120. This result suggests that the formed fillet differs depending on the solder volume at the front fillet side. This is caused by the small wet-spreading property of Pb-free solder.

The printed solder should be managed and designed, by paying attention to which parts of lands and components are faded. However, printing at IC116 is not necessarily desirable considering the heel fillet that cannot be seen in a visual inspection.