Electronics Forum | Mon Jul 16 10:44:29 EDT 2007 | Jacky
Hi All, Recently, we encountered strange defect at our SMT line. We can see solder ball spatter around at one of the component pad. This lead to insufficient solder defect at 1 side of the component. The other side of the component look good(Meet
Electronics Forum | Mon Nov 07 08:27:56 EST 2005 | chunks
It could be you are drying out your solder paste. Most flux formulations are alcohol based and after a few hours can dry out. This can can lead to dewetting and solder balling as well. Especially if you do not homeplate your R's and C's. A simple
Electronics Forum | Thu Nov 09 23:01:34 EST 2006 | davef
Tin/lead alloys tend to oxidize very easily, affecting solderability. Use the largest particle sized paste possible, because as the particles decrease in size their total surface area per unit mass increases, effecting: * Demands on the flux increase
Electronics Forum | Tue Dec 03 11:59:01 EST 2002 | slthomas
We haven't run a profile yet....probably because we're a-feared to. We can't do topside preheating here to any degree because we use an aluminum plate for aligning hundreds of top side through-hole components (pots, switches, buttons, LEDs) that te
Electronics Forum | Wed Aug 09 11:59:19 EDT 2017 | dleeper
As you already know, it depends on the paste. There isn't really a rule of thumb, but less time exposed it better. The issue is the flux exposure to the air and ambient conditions. The flux can evaporate or absorb moisture from the air. If the paste
Electronics Forum | Tue Dec 10 14:10:38 EST 2002 | Randy Villeneuve
Steve, I wave solder most if not all our boards with selective wave pallets. I did not catch if the solder balls were on top of the board or on the bottom but that will make a difference on what to do to get rid of them. Pallets are good and bad. On
Electronics Forum | Tue Dec 17 08:38:30 EST 2002 | Randy Villeneuve
Jim, In most cases if you can eliminate a process you will save money. With that in mind, an all surface mount or all through hole design is prefered. There are alternatives to that rule, like hybrid designs that can be pin and paste soldered. It al
Electronics Forum | Mon Dec 16 17:35:43 EST 2002 | davef
Jim Consider issuing a purchase order to your assembler for the purchase of selective wave soldering pallets required to solder your board. That way, you: * Own the pallets. * Can take the pallets with you should you decide that another assembler
Electronics Forum | Tue Dec 17 13:42:04 EST 2002 | robf
There are a few emerging technologies that have been growing in popularity for the past few years. Pin through paste, press fit connectors and selective soldering machines seem to be displacing custom fixtures. Most of the mixed technology boards o
Electronics Forum | Fri Mar 04 01:08:19 EST 2011 | kemasta
Thanks davef Bridging:- There is no heat sink on the BGA, the heat sink will be fix after relow. I do believe paste had something to do with it, but currently this defect didn't appear so oftenly, so we think that the main root cause is not from the
