Also, have you verified that the holes are actually shut?  Just 
     because that is in the tolerance, doesn't mean it has happened.
     
     Regarding the opens which occur after being shipped clean from the 
     supplier, there are things that can happen to cause this.  Two items 
     are: very thin plating in the via holes, or something attacked the 
     normal plating subsequent to the plating operation.  These should be 
     addressed with the supplier.  
     
     Matt Byrne


______________________________ Reply Separator _________________________________
Subject: Re[2]: Open vias problem
Author:  [log in to unmask] at SMTPLINK-HADCO
Date:    5/17/96 04:21 PM


     
     before we go too far down the road with the "plated shut via", 
     i have a question that would help me distinguish the 
     problem/condition:
     
     is the via plated shut, or is it a matter of some of the via locations 
     not being solder cleared completely through the HASL process?
     
     i am infinately familiar with the latter, but am somewhat surprised 
     that the former would be requested by a PWB manufacturer...
     
     the latter condition doesn't represent a reliability problem based 
     on my knowledge (yes, i am open to being educated! (-;), whereas
     i can understand each of the concerns raised with respect to a 
     "plated shut" via.