Electronics Forum | Wed Feb 08 07:52:21 EST 2006 | davef
'TAL' is a poor measure of solder connection heating. In a reflow process, what you need is about 5 seconds at liquidus for the specific solder plus: * 20*C when soldering to Cu. * 35*C when soldering to Ni. This time over temperature is measured
Electronics Forum | Mon Jun 12 22:00:51 EDT 2000 | Dave F
Could be. What are your profiles? 2) Au finish fail => Could be, but that the connections can be made with hand soldering makes this a low probability cause, assuming the activity of the flux used in hand soldering is not significantly different fr
Electronics Forum | Tue Jun 07 10:38:34 EDT 2011 | davef
Boots: Here's several methods for guessing at the amount of solder on your connection: * First, 'Down & Dirty' ** Assume that the solder is flat, which is reasonable since it's 'flattened' by the component package ** Assume 100% paste transfer from t
Electronics Forum | Thu Jun 28 15:38:37 EDT 2012 | davef
Matthew: That you can get solder flow when hand soldering, but not when reflow soldering, seems to be telling you that you're not getting the connection warm enough during reflow. You need to have those connections liquidous + 20*C for at least 5 sec
Electronics Forum | Tue Sep 24 22:29:04 EDT 2002 | davef
First, I don't have a clear fix on the problem. Please drill-down to more detail. We appreciate that you probably don't know the parlance. Just describe what you have and then what you'd like to have. Second, most 0402 LED are fabricated just lik
Electronics Forum | Thu May 31 10:21:16 EDT 2001 | davef
On "Flip Chip/uBGA Under-fill Visual Standards" � The third "Satisfactory" [The under-fill if by design should be visible � ], here the notation "if by design" is unclear. Does "according to product documentation" get to the point? The first "Acc
Electronics Forum | Mon Jun 13 21:08:12 EDT 2005 | davef
Paramjeet Singh Gill So, you underfil before cleaning. Interesting. * What is it about your underfill that prevents the OA flux from attacking the FC solder balls? * Who is the underfill fabricator and product? Getting back to your solder balling
Electronics Forum | Wed Feb 23 12:42:28 EST 2011 | davef
If we understand correctly, your SMT solder connections remelt when passing through the wave solder machine and your QA-people don't like it when that happens. It's nice not to remelt this solder, but as long as the board meets your acceptance stand
Electronics Forum | Thu Aug 13 10:58:58 EDT 2009 | davef
First piece of advice: build the board as you would any other board. Probably, you will be surprised at the holding force of the solder of the connections of the BGA, because the surface area of the solder is very large compared to the weight of the
Electronics Forum | Mon Sep 28 16:15:57 EDT 2009 | davef
That your solder connections reflow properly when heated with a soldering iron, indicates that that your reflow recipe needs improvement. * Thermocouple the pads that require touch-up and adjust your oven recipe to assure that they reach liquidous+20
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