The Footprint Optimisation Project (FOP)

The DeltaProto Footprint Optimisation Project (FOP Project)

In various projects, we noticed that pogo pins -- and other contact pins -- with a closed solder pad sometimes tend to stand crooked after soldering. The cause turns out to be subtle: a small deviation in the amount of solder paste already determines the perpendicularity of the pin. Too little paste results in a weak connection, while too much paste acts as a cushion and pushes the pin out of alignment -- sometimes so far that it no longer fits properly through a housing.

To better understand this, we conducted an experiment in our PCBAProtoLab Twente (located at the Fraunhofer Innovation Platform for Advanced Manufacturing at the University of Twente) with different pad diameters, paste quantities, and vias in pads. The latter turns out to be promising: vias in pads allow excess paste to escape through the bottom side, resulting in a more stable pin position.

Follow-up research still needs to determine the optimal ratio between pad and via diameter.

We'll keep you posted on our findings.

HappyEngineering PCBAProtoLabLearnings