http://www.pcb007.com/ PCB fabricator news from around the world: PCB007 Interconnect separation is usually expressed as a crack that propagates at the internal interconnection. This failure mode produces a crack that is wedge-shaped, with the large end on the side of the foil closest to the middle of the PWB. An interconnect failure frequently develops slowly over time, accumulating damage at a constant rate after onset. http://www.pcb007.com/pages/zone.cgi?a=70391 Wed, 18 Aug 2010 21:42:00 GMT Developers of mil/aero and other high-rel applications depend on solid failure analysis. Paul Reid discusses how thermal cycling will cause a robust plated through-hole to crack slowly over time. Plotting a resistance graph of damage accumulation allows technologists to determine onset, rate of accumulation and whether the damage is accelerating linearly or exponentially. http://www.pcb007.com/pages/zone.cgi?a=58530 Wed, 18 Aug 2010 12:39:00 GMT Corner cracks are observed less often than barrel cracks, but with high-rel boards, we can't be too careful. Unlike barrel cracks, which can fail catastrophically, knee cracks tend to propagate over time. The damaged pad actually resembles a funnel and the warp and weft of the glass give the funnel an uneven, puckered shape. http://www.pcb007.com/pages/zone.cgi?a=69569 Sat, 10 Jul 2010 12:07:00 GMT