15

Poor Hole Fill
Poor hole fill can be caused by incorrect pre heat, no flux or a total miss of the solder wave. In the example there is no evidence of solder in the through hoes or vias. It is more than likely that the board failed to make contact with the wave which could be due to wave height, damaged fingers or pallets not being maintained. Incorrect loading of the board in to the systems may also have caused this fault. It is possible that the quality of the through hole plating may have been responsible. This is less likely to be the cases as it would be very apparent on other boards in the batch.