Electronics Forum | Wed Oct 04 14:18:05 EDT 2006 | C.K. the Flip
The main cause of voids is your flux out-gassing during reflow. Try a little "knee" or slight soak in your thermal profile to dry out the volatiles a bit. Typical soak ranges from 130 deg. C to 170 deg. C for around 30-90 seconds.
Electronics Forum | Wed Oct 04 16:24:48 EDT 2006 | russ
try Alpha OM5100 this is a noclean paste that we use and have done the same thing you are now, reflowing pbfree with pb paste, we run to max temp of 230C with this paste and use a straight ramp with no soak profile is about 4 mins long from ambiant
Electronics Forum | Thu Oct 05 16:12:09 EDT 2006 | Mario Scalzo, SMT CPE
* Try 1.5C / sec from RT to 165C * Hot soak at 165-175C for up to 2 minutes (I'd start with 60 seconds flat soak.) * 60-90 seconds TAL (I's start with 60) * 230-240C Peak. Thanks, Mario
Electronics Forum | Fri Oct 06 15:43:33 EDT 2006 | Mario Scalzo, SMT CPE
What I usually do is keep the peak temperature about 5-10 deg C below the peak temperature of my lowest rated component, then set everything else up around that. Worse case scenario is to just extend the time above liquidus (TAL) in 5 second increme
Electronics Forum | Tue Oct 17 09:27:23 EDT 2006 | SWAG
We had a build that showed a relatively high occurence of BGA voids like you were seeing. It was a very small volume first article that took a long time to get through the line so the paste sat on the boards too long. As we ramped up TACT time in p
Electronics Forum | Thu Oct 05 16:03:31 EDT 2006 | C.K. the Flip
I had horrible experiences with a certain brand on multiple types of BGA's (I choose not to mention the brand). The paste was nice and active, but almost to a fault when it came to BGA's. Finally, I arrived at a profile with a more agressive ramp u
Electronics Forum | Wed Oct 04 17:15:23 EDT 2006 | russ
that question I think I will punt it on over to some of the experts here. I really do not the "why". voids for me have always been related to the escape (lack of) of the "stuff" that is in the paste. I have seen diff pastes perform differently rel
Electronics Forum | Fri Oct 06 08:21:26 EDT 2006 | inds
Mario, what happens when there are components on the boards that are not rated to take temperature of 230-240 C Peak for a mixed assembly. I guess there are tons of sn/Pb components that have rated temp of 225-230 C.. So in guess you might want
Electronics Forum | Thu Oct 26 11:49:54 EDT 2006 | sms_don
CW, The good news is that you are not trying to use SAC paste with SnPb balls for that would be a void generator due to the ball being liquidous while the SAC paste is still in a flux cleaning stage. Two points to consider: One, voids are not an i
Electronics Forum | Thu Mar 16 10:41:34 EST 2000 | Russ
Are we talking midship SMT or wave soldering? SMT - I have found the best method is not having them (WOW) this can be accomplished through pad design, aperture design, placement accuracy, and profiling, It is my understanding however, that these
