I have been unable to locate a system assembly level 
        spec that details allowable warp and bend of an SMT 
        PCBA while it is being installed into a chassis of 
        some kind. 
        
        I have concerns of potential fractures of SMT 
        solder joints if the PCBA is allowed to flex "too much" 
        due to installation of daughtercards, I/O cards, power cords, 
        etc...but have no idea how much is "too much".
        
        Based solely on flexing some out-of-date circuitry
        with my bare hands, it seems evident to me that it doesn't 
        take much flex or bend to create an open or intermittent circuit 
        connection.
        
        To give you a visual idea of the kind of flex I am looking at that
         many of you may be familiar with, consider pushing the power supply 
        cable connectors of a PC power supply into an IBM PC Compatible 
        motherboard...there are generally speaking, one or several 208-pin 
        PQFP's in the area as well as numerous SOICs, R's and C's.
        
        Can anyone point me toward an allowable flex spec for a PCBA in order to 
        eliminate the incidence of assembly and handling induced SMT joint 
        problems?
        
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