08

Solder Short
Solder shorts are generally on the increase in the wave soldering process this is due to the ever decreasing component pitches used in manufacture. In the past the pitch of terminations were 0.050" now we see many conventional terminations being used on a 0.025" pitch. Solder shorting occurs when the solder does not separate from two or more leads before the solder solidifies. Increasing the flux solids or quantity is one way of decreasing shorting. A reduction of the lead length and the pad size will reduce the amount of solder being held on the base of the board. The example shown is a connector on a 0.025" pitch which was improved through changes in the pad design. Alternative pads were increased in length on the exit side of the wave. This made the actual separation distance between the adjacent termination larger and decreased the shorting.