Electronics Forum | Wed Nov 06 10:03:59 EST 2013 | rgduval
Hi, Peter, I'm not an authority on surface finish thickness, and it's effect on reflowing, so, I can't advise on that front. If the boards are a week old, and ENIG, I would not suspect surface contamination. It's always a consideration, of course,
Electronics Forum | Fri Jul 07 09:15:23 EDT 2000 | K. Chak
Hi Dave, This particular p/n calls for print&etch for wet process..and the problem occured due to surface contamin. with resist residue resisting copper from etching off. The high pressure nozzle was a problem at developing oper. and it is fixed now
Electronics Forum | Tue Jul 30 08:37:39 EDT 2002 | davef
When you talk about 'poor wetting', 'dewett', 'no wets', etc.; are you seeing solder pulling back or away from the pad? Please describe the condition. Dewetting. The condition in the solder joint in which the liquid solder has not adhered intimate
Electronics Forum | Thu Sep 07 03:47:07 EDT 2006 | vicknesh28
I have been getting non wets on fine pitch QFP packages on random leads during reflow process. I noticed that every time there is some flux residue left between the non-wet lead and the solder pad. No residue was not observed on the rest of the good
Electronics Forum | Thu Sep 07 08:44:17 EDT 2006 | vicknesh28
Did check the coplanarity of the failed lead and found it to be as good as the wetting leads.
Electronics Forum | Thu Sep 07 18:32:51 EDT 2006 | vicknesh28
Yes the part is reworked. It solders when it's reworked.
Electronics Forum | Thu Sep 07 09:08:57 EDT 2006 | Bubba
OK, part touching paste before reflow? Check part. Maybe bad plating. Check reflow profile by slowing conveyor.
Electronics Forum | Thu Sep 07 10:39:34 EDT 2006 | vicknesh28
Can u elaborate on the bad plating? Have u had any experience on this before? The component has 90/10 Tin lead plating
Electronics Forum | Thu Sep 07 14:43:33 EDT 2006 | davef
Questions are: * So after you spot one of these leads sitting on a nice pillow of solder, what happens? * Do you rework the part? * Does it take solder? * What do you do to make it take solder, if it does take solder?
Electronics Forum | Fri Sep 08 08:00:41 EDT 2006 | davef
That's your clue. Your reflow is running ~240*C and your soldering iron is running ~370*C. Dial-up the heat.
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