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Date: | Fri, 11 Nov 2016 15:13:36 -0500 |
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(1) your pwa is 1st article
(2) look like failure is after reliability test - failed rel test
(3) repair is not going cut it. you need to find out what is wrong -
deficient design, MFG process fault? or MFG tolerance issue, Material
selection issue related to your rel test parameter:e.g. Tg is too low for
the thermal shock you intend to do... or your board is not balanced and
warp like potato chip during shock, etc. etc.
unless you FA showed you what is wrong, fix is easy - wire the net
externally (jump wire if you can do it for 1st article of function only
test... but you can forget the rel test... provide no EMI issue, high
speed or ground bounce).
my 2 cents
> We have a couple of expensive first time build boards that failed ICT in
> assembly due to what appears to be cracked vias. Adding solder to the via
> hole seems to fix the issue.
>
> What are folks thoughts on plugging vias with solder to fix them? What
> risks are we taking by adding solder vs another technique? Could folks
> recommend alternate repair techniques that may provide better
> thermal/vibration?
>
> Also, I'd love to hear up alternate possible root causes? This problem
> screams insufficient plating during fab or thermal shock during assembly,
> but I'd like to investigate all possible failure modes. This is a
> multi-layer double sided SMT + wave rigid-flex PCB and the cracking is on
> the rigid portion.
>
> Thanks,
> Stephen Golemme
> Manufacturing Engineer, Makani
> 650-214-5647
> solveforx.com/makani
>
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