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March 2013

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Subject:
Re: Conductive path failure in thermal cycling
From:
Ioan Tempea <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Ioan Tempea <[log in to unmask]>
Date:
Fri, 1 Mar 2013 21:05:42 +0000
Content-Type:
text/plain
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text/plain (70 lines) 
ENIG

Ioan Tempea, ing.
Ingénieur principal de fabrication / Senior Manufacturing Engineer
[signature002]<http://www.digico.cc/>

950 RUE BERGAR, LAVAL, QC, H7L 5A1<http://g.co/maps/2gh3f>
T+ 1 (450) 967-7100, EXT244
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  [signature001] <http://www.facebook.com/pages/Digico/277076778479>
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Lauréat Dunamis 2012<http://digico.cc/dunamis-2012/>
Entreprise manufacturière / Gestion du capital humain

De : [log in to unmask] [mailto:[log in to unmask]]
Envoyé : March-01-13 2:30 PM
À : TechNet E-Mail Forum; Ioan Tempea
Objet : Re: [TN] Conductive path failure in thermal cycling

Hi Ioan - what is the assembly surface finish?

Dave Hillman
Rockwell Collins
[log in to unmask]<mailto:[log in to unmask]>



From:        Ioan Tempea <[log in to unmask]<mailto:[log in to unmask]>>
To:        <[log in to unmask]<mailto:[log in to unmask]>>
Date:        03/01/2013 10:40 AM
Subject:        [TN] Conductive path failure in thermal cycling
Sent by:        TechNet <[log in to unmask]<mailto:[log in to unmask]>>
________________________________



Dear Technos,

RoHS assembly, soldered with SAC305 alloy, 0.075" thick 14 layers PCB, failing after 250 cycles (-20 C to 125 C).

Failure mode is crack between the traces and pad at 3 places. Happens on 2 TH components. Traces are 0.0055" wide, pads are 0.022" in diameter on the via side or 0.065" on the component side. There is no tear dropping.

Should I bother figuring out if manual soldering of the TH component fragilizes the trace-pad junction, or this is an obvious case of design induced failure?

Thanks,

Ioan Tempea, ing.
Ingénieur principal de fabrication / Senior Manufacturing Engineer
[signature002]<http://www.digico.cc/>

950 RUE BERGAR, LAVAL, QC, H7L 5A1<http://g.co/maps/2gh3f>
T+ 1 (450) 967-7100, EXT244
------------------------------------------------------------------------
 [signature001] <http://www.facebook.com/pages/Digico/277076778479>
------------------------------------------------------------------------
Lauréat Dunamis 2012<http://digico.cc/dunamis-2012/>
Entreprise manufacturière / Gestion du capital humain


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