Electronics Forum | Tue Sep 25 14:08:59 EDT 2001 | davef
Oooo, the solder on the pad and PGA ball is flowing during reflow down the via to the secondary side? Why didn�t you say so?? ;-) Why would you expect that gravity and capillary action wouldn�t force solder to flow down the solder plated via to the
Electronics Forum | Wed Nov 14 14:44:10 EST 2007 | grantp
Hi, Those via's sure do sound large, and I think the designer must have made a mistake in the PCB design do you think? From looking at our PCB designs, if we moved to via in pad, it would really reduce the size of the PCB, so this is an important i
Electronics Forum | Mon Sep 24 18:00:58 EDT 2001 | jagman
Does anyone know the cause(s) of solder flowing through a via to the other side of board during reflow causing solder bumps on opposite side? Is this mainly a design issue or could it be process related? Any help is appreciated.
Electronics Forum | Mon Sep 24 20:33:34 EDT 2001 | davef
Assuming you're seeing this during wave solder, the via acts like a heat pipe conducting 450�F [or whatever] air to your solder balls. Check the fine SMTnet Archives for similar threads and perspective on the direction to take.
Electronics Forum | Mon Sep 24 20:49:59 EDT 2001 | jagman
I'm not seeing this during the wave solder process, rather the REFLOW (convection) process. The board was design with the vias located "in" the land area.
Electronics Forum | Tue Nov 13 08:11:16 EST 2007 | grantp
Hi, What is this unacceptable? Designed the PCB is much easer if this is possible, so it would be really good to know why via in pad is a problem in production. Grant
Electronics Forum | Tue Nov 13 09:32:28 EST 2007 | kpm135
For the simple fact that the via in the middle of the pad causes the solder to wick into the hole instead of flowing out across the pad and part. Thus cause insufficient solder issues.
Electronics Forum | Thu Nov 15 08:25:08 EST 2007 | rgduval
I do think that the designer goofed, and used too large vias. I believe he only used on size via on the entire board, regardless of whether it was in a pad, or out on the board. I have seen vias in pad work, though. From a manufacturing standpoint
Electronics Forum | Thu Jan 06 08:03:47 EST 2005 | davef
On solder in vias: It looks like the via are not solder masked well and pick-up solder either: * Solder coating ... OR * During leveling It's possible that the design specifies openings in the solder mask for these via. On solder in the unsupporte
Electronics Forum | Mon Nov 05 07:22:02 EST 2007 | aj
Hi, We have had this before - yes they can be plugged and metalised on top . aj...
