Electronics Forum | Thu Nov 21 06:36:30 EST 2002 | Ben
I'm doing SMT of lead-free solder BGA on FR4 Ni-Au PCB. The solder paste I'm using is Sn/Ag/Cu and reflow with peak temp at 240C. I found there are voids(1-2) in almost every solder joint(500 micron in dia) under xray. And the void size is violate th
Electronics Forum | Sun Nov 22 18:40:47 EST 2009 | 89jeong
Hi The bubble shows only around component body after ir reflow. I think bubble means that there is a moisture. How do you dry the PCB(?) before IR reflow? Thanks Ju-young.
Electronics Forum | Tue Mar 01 11:19:47 EST 2011 | jeddmartens
I have no knowledge into PCB designing with surface mount components, all my experience has been with through hole components. I now have to design PCBs using surface mount parts. I have a few questions I was hoping someone could answer. Can a PCB w
Electronics Forum | Mon Mar 22 19:46:17 EST 2004 | pdeuel
The bottom side is going into reflow somewhare near melting point of solder. Reduce bottom side temprature. Get a good mole so ramp and soak tempratures can be checked on bolth sides of the PCB. The object is to keep bottom side parts from approching
Electronics Forum | Fri Jan 04 15:42:03 EST 2002 | nwyatt
There are several implications: - some lead free alloys do not form an acceptable solder joint when used with lead contaning paste. (ie. Bismuth) - if you use both lead free and lead containing components, you will have different solder joint compos
Electronics Forum | Thu Jul 20 16:45:54 EDT 2000 | Darby
Good morning Bob. Darby from Australia here. We sometimes see an orange peel type finish on our reflow solder joints when viewed under the microscope. Any ideas on what causes this ? Should I worry about it. I use a straight rise profile ( no "platea
Electronics Forum | Sat Dec 11 12:15:21 EST 1999 | Steve Thomas
We have a pretty challenging board (2-up panel, 15"x20", 48 20mil pitch QFP 100's and 2 25mil QFP128) that gives us LOTS of lead bridging on the 20 mil parts. There is typically very poor wetting on these parts also, and some joints just flat aren't
Electronics Forum | Thu May 26 07:50:33 EDT 2011 | scottp
What process steps have been completed before the cross-section? What type of devices have solder cracks? Are the cracks found after just normal processing or after some type of validation testing? It is very unlikely to be a heating/cooling issue
Electronics Forum | Thu Jun 28 09:54:06 EDT 2012 | mosborne1
Dave, They rework fine. All solder joints on the whole board look great especially for lead free sac305. Here are the reflow specs: SAC305 no clean solder paste – Kester EM907 Kic thermal profiling device – 50%process window green light profile. • M
Electronics Forum | Mon Nov 25 22:08:05 EST 2002 | Ben
Thanks for the advise. I got the advise from my solder paste vendor to increase the time above melting point for flux outglassing to escape. I tried but no big help. For the moisture issue, actually I've try to bake both the PCB and components at 12
