There are some common areas inexperienced BGA assembly technicians may run into in the reworking of BGAs including:
Popcorning and component damage -this is particularly prevalent on very thin devices (MSD Class 1)
Component damage due to overheating
Improper temperature profile
Application of solder paste on the land patterns on ceramic parts
Each of these problem areas may be mitigated by either having properly trained personnel or by using a professional contract rework facility such as BEST perform the work.