Victor, it depends: it  is layout dependent  as well as process  
dependent.  you also need to know what reflow temperature you use and  
how many times your intended total reflow for the whole assembly....  
the best way to find out is fly probe test prior to and after  
multiple reflow, if you got suspected area pop open - delam or  
anything, you should be able to visual inspect and electrically find  
out (if you got large area resin rich, you might have warpage too...  
another story).  imo.
      jk
On Jul 25, 2014, at 1:25 PM, Victor Hernandez wrote:

> Wayne,
>
>    Are you aware of any IPC STDs which cover this anomaly or even  
> bench marking?  I hope PWB/PCB gurus will chime in on this topic.
>
> Victor,
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Thayer
> Sent: Thursday, July 24, 2014 3:44 PM
> To: [log in to unmask]
> Subject: Re: [TN] PWB, rich epoxy area
>
> Resin rich will be weaker, lower dielectric constant, more subject  
> to cracking, higher coefficient of expansion. Actual effect on  
> reliability/product use depends on how close the design relies on  
> "normal"
> laminate specs.
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Victor Hernandez
> Sent: Thursday, July 24, 2014 3:37 PM
> To: [log in to unmask]
> Subject: [TN] PWB, rich epoxy area
>
> Fellow TechNetters:
>
> Can a rich epoxy area/site within a PWB laminate be harmful. What can
> happen and what could be the reason for the rich epoxy area? Where  
> can I
> fins supporting literature in IPC STDs and or bench marking.
>
> Victor,
>
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