During wave soldering, small solder balls can be formed. These balls appear mostly on the solder side of the printed circuit board, but can sometimes also be found on the component side. The risk of the formation of solder balls seems to increase with the increasing package density, especially when SMD's are mounted at the solder side. Just in that case they are the least desirable.
In this document we will discuss the reasons for the appearance of solder balls and methods to prevent solder ball formation.
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