Are solder balls a defect or process indicator? The solder balls were are observing are mid chip solder balls on low profile SMD resistors and caps. The mid chip balls typically wash off and X ray does find a few solder balls wedged under SMD devices (right now about 8 per board). I think they are process indicators and do not need touch-up (I really think desoldering the part and resoldering the part is more deleterious to reliability than these entrapped solder balls.

I went over the IPC-A-610C and found the following pertaining to solder balls. 
 Para 6.5.3.1 and Para 12.4.10  Excess solder. Target condition  is no evidence of solder balls on the printed wiring assembly
                                      Acceptable condition Class 1/Process Indicator Class2,3. Entrapped or encapsulated solder balls that are within 0.005 inch of lands or conductors, or exceed 0.0051 inch in diameter.



Tom Gervascio
Senior Process Engineer
Sparton Electronics
(352) 540-4040

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