From how you described it, there are multiple boards that are failing and my question is, are they all in the same area/via(s) or no real patterns or locations? If it is a single via or even a couple next to each other, you may want to do as Wayne said and drop a wire in the hole and solder. That said, if that via(s) connects to an internal trace/plane, I would also add additional wires to the board to ensure you connect all the points on the net. If these are scattered all around and not the same on each board, man, you go an issue that's management isn't going to like... :-[ Best of luck...
Later...
Scott Decker – Senior Analyst, Drafting & Design Services CID+ – Electronic Systems Center
UTC AEROSPACE SYSTEMS
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-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Thayer - EXT
Sent: Friday, November 11, 2016 12:30 PM
To: [log in to unmask]
Subject: [External] Re: [TN] Fixing Cracked via holes
Drop a wire in it when you solder it and finish off the wire on the via ring or nearby connected pad.
Without doing FA, you don't know how reliable this will be in the field unless it is simply a double sided board. In that case, the wire fix is guaranteed to make that particular interconnect, but what does the failure say about the surrounding vias? Are they just about to go?
Good Luck!
Wayne
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Golemme
Sent: Friday, November 11, 2016 11:14 AM
To: [log in to unmask]
Subject: [TN] Fixing Cracked via holes
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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