at time zero - as out of factory - no fracture allowed - if you have
fracture at BGA solder mask area, you got crack initiation site - you
need to change solder mask openning to avoid such a fault IMHO.
At end of sequential test (vib, thermal shock, drop/impact), 20%
max.... Noted in qual report for review as item of susceptibility of
overall system design - program manager have to sign up for knowingly
accept the reliability risk. If it is go to sky or some places that
repair and overhaul are not allowed, you have to have redundancy
exist to avoid potential failure risk. 20% is based on electrical
design and thermal design requirements for device under overall
assembly level design... not cast in stone and not universal (23% was
maximum based on FEM and design assessment of worst case performance
in this case to derive to 20%, for example, max environmental temp
plus assembly add on operational temperature for signal current
carrying capability and thermal conduction capability - special
attention to the power and ground..etc.etc)... for example.
hopefully, it helps.
jk
On Apr 6, 2018, at 6:53 AM, <[log in to unmask]> wrote:
> Fellow TechNetters:
>
> I was surprised that very little input was provided.
> Therefore, since it Friday Elements QUIZ day. I will take advantage
> of the high volume traffic day.
>
> Victor,
>
> From: Hernandez, Victor G
> Sent: Thursday, April 5, 2018 10:22 AM
> To: TechNet E-Mail Forum <[log in to unmask]>
> Cc: Hernandez, Victor G <[log in to unmask]>
> Subject: IPC-A-610G, section 5.2.9,, Solder anomalies-Fractured
> solder, Defect 1, 2, 3 (Axial leaded device)
>
> Fellow TechNetters:
>
> Is there a percentage associated with the statement "Fractured
> Solder" in the above stated IPC STD section?
> I did not a similar statement, Fractured Solder, for Surface Mount
> Devices and Surface Mount Area.
> Is there an acceptable percentage of the solder joint lead
> interface that can be fractured?
>
>
> Victor,
|