TECHNET Archives

April 1997

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Date:
Wed, 2 Apr 97 16:00:00 -0800
Content-Type:
text/plain
Parts/Attachments:
text/plain (52 lines)
Item Subject: Assembly - via hole plugging and solderballs
     What you are seeing is the outgassing of the flux through the wave 
     soldering process.  This is a very common problem and the best method 
     is to not mix mixed technology boards with plugged vias.  I have never 
     heard of any solution to this when wave soldering is involved.


______________________________ Reply Separator _________________________________
Subject: Assembly - via hole plugging and solderballs
Author:  Non-HP-Marti.tully ([log in to unmask]) at 
HP-Vancouver,shargw2
Date:    4/2/97 2:29 PM


Several of our PWB suppliers have used a via hole plugging process with the 
following sequence:  LPI, HASL, partially plug via hole (component side). 
   With mixed technology boards, our assemblers (in house, contracted etc.) 
all experience a phenomenon where the solder erupts from the top of the via 
during the wave process.  The eruption looks like a volcano and varies in 
severity.  This eruption  results in several problems including solderballs. 
  Most of the plugged vias lie under components and the spacing between vias 
can be equal to or <8mils.  Many components sit very close to the board's 
surface.
     
This seems the  PWB industry preferred method to plug holes when LPI is 
used.    How do assemblers prevent the eruption of the solder through the 
top of the plugged via during wave?  Is this a common problem in assembly 
 or rare?  
     
*************************************************************************** 
* TechNet mail list is provided as a service by IPC using SmartList v3.05 * 
*************************************************************************** 
* To subscribe/unsubscribe send a message <to: [log in to unmask]>   * 
* with <subject: subscribe/unsubscribe> and no text in the body.          * 
*************************************************************************** 
* If you are having a problem with the IPC TechNet forum please contact   * 
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask]      * 
***************************************************************************
     

***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To subscribe/unsubscribe send a message <to: [log in to unmask]>   *
* with <subject: subscribe/unsubscribe> and no text in the body.          *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact   *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask]      *
***************************************************************************



ATOM RSS1 RSS2