Dear Mr. Werner,
Thanks for the inputs
Rgds
Werner Engelmaier /* wrote at Thu Aug 07 23:55:59 IST 2008:
>Hi Pradeep,
>NO, smear will not form uniformly.
>YES, smear will affect the quality and reliability of the PCBs at every stage
>of subsequent work and operational use.
>THEREFORE, effective desmear is a must.
>HOWEVER, that does not mean that you need a lot of positive etchback, because
>that too degrades quality and reliability.
>
>You need to be aware that desmearing Pb-free soldering compatible PCB base
>materials, typically phenolic cured, do not respond to smear removal like the
>traditional FR-4 PCBs.
>
>All of this, and of course much more, is detailed in my White Paper
>"Recommendations for PCB FAB Notes and Specifications in Printed Circuit Board Drawings
>for SnPb and Lead-Free Soldering Assemblies, the Qualification of PCB Shops
>and Activities to Assure Continued Quality."
>
>
>
>Werner
>Future workshops:
>Reliability Issues with Lead-Free Soldering Processes, September 22,
>Schaumburg
>Failure Mode and Root Cause Analyses Reliability (Fatigue, Brittle Fracture,
>ENIG), September 22, Schaumburg
>Solder Joint Reliability: Parts 1 & 4, Oct. 9, Moscow, Russia
>Solder Joint Reliability: Part 4, Oct. 17, Timisoara, Rumania
>Solder Joint Reliability: Parts 1 & 4, Oct. 22, Tallinn, Estonia
>
>
>
>**************
>Looking for a car that's sporty, fun and fits in your budget?
>Read reviews on AOL Autos.
>
>(http://autos.aol.com/cars-BMW-128-2008/expert-review?ncid=aolaut00050000000017 )
>
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