Electronics Forum | Tue May 02 13:57:21 EDT 2006 | patrickbruneel
What you can do is perforate the board holding rim by drilling holes of 0.6mm (similar to via's). This will reduce the mass and heatsinking capacity, allow excess flux drainage and facilitate convection heat contacting the board through the holes. Th
Electronics Forum | Tue Mar 04 01:00:19 EST 2008 | gdzuber
Recently I have been hearing and see this excess flux residue problem at several companies, US, Mexico, and Japan. It seems to have increased recently. In fact, it seems so common that it seems normal, but if everything is correct, a re-flow oven sho
Electronics Forum | Mon Jan 17 17:38:29 EST 2011 | bandjwet
All: I am reaching out to get some suggestions on the right flux to use as well as a recommended cleaning process for soldering a KOVAR RF shield using 80/20 Au/Sn solder to a ceramic hybrid. The recommended profile is 4-5 min at 280C and at least
Electronics Forum | Tue Sep 25 14:38:05 EDT 2001 | nwyatt
1. SRT has been recently calibrated - problem is too many hands in the machine and careless mistakes. The profile is good and has been recently checked by a fellow from Genrad. 2. We are relying on the left over solder from the previous joint and
Electronics Forum | Tue Jun 04 16:12:41 EDT 2002 | Bob
The original profile had a higher ramp rate, and the apertures were 100%. The ramp rate is now much gentler and the addition of a small soak area around 160 � 170 degrees should burn off any excess flux. Appertures are now smaller and we get no leac
Electronics Forum | Mon Mar 24 08:57:20 EST 2003 | russ
I don't know if I would call it a "blow hole". what I believe happens (I don't have a camera to watch spheres during the reflow process) is that when the flux starts heating up, expansion, bubbling, or something physically displaces the balls. We fo
Electronics Forum | Fri Sep 12 06:02:55 EDT 2003 | Neil Trelford, Nortel
Even though you use a no clean process, it is still possible that some type of fluid has created the "short". Production lines are notorious for using cleaning chemicals on PCBs to clean excess flux after rework on other areas. Unless this type of c
Electronics Forum | Wed Apr 04 19:31:57 EDT 2007 | rgduval
Dave, We're reworking with flux and solder. We're observing "exploding" joints, as well...as though something is trapped in the joints (either excess flux not burning off during solder, or residual moisture). As mentioned above, I spoke with the f
Electronics Forum | Mon Jul 02 18:40:33 EDT 2012 | joeherz
We used to have a Nuclean 324 that was running closed loop with a DI water recirc system. We also had problems with foaming that was solved with a relatively simple fix. We bypassed the final rinse solenoid so that it was always running. This allo
Electronics Forum | Tue Sep 25 13:01:48 EDT 2001 | Hussman
If the flux you are applying by brush is alcohol based, use some alcohol on a few failed PCBs and retest. It souldn't take a lot of flux to reflow the balls to a pad that's already covered with solder and flux from the first BGA - unless you are cle
