Ioan,
Is the cracking limited to a specific cap value/package? If so, there is
non destructive lot testing that can be accomplished. We determined that
on ceramic caps, with the largest capacitance in the package size, was
susceptible to micro-cracking even before reflow. We pushed the
requirement on our supplier if you have enough volume to cost justify it.
If not, it can be done at your incoming. It consists of unpowered thermal
shock, alcohol bath and electrical leakage measurement. Reflow only
instead of hand soldering will also reduce the chances of damaging a good
part as well. If your problems are widespread on assemblies, then your
cracking problem might lie elsewhere. Feel free to contact me for more
details.
Jim Carlson
Sr Quality Assurance Engineer
Rockwell Collins EW-SIGINT
Phone 443-489-9121
Fax 443-489-9290
"Tempea, Ioan" <[log in to unmask]>
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[TN] Finding cracked capacitors
Hi Technos,
a never ending story, ceramic caps that crack, possibly due to
depanelizing. The damage is not visible, unless the cap is cross
sectioned.
Is there any testing, thermal cycling or something like that, that could
show the damage real fast?
Thanks,
Ioan
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