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 | 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.
Electronics Forum | Thu Sep 07 10:32:12 EDT 2006 | slthomas
Is the solder reflowing on the pad but not wicking up the lead, or does there appear to be insufficient solder to wet both, or is it not reflowing at all, or.....? Have you verified your profile? What is the condition of your paste (expiration date,
Electronics Forum | Thu Sep 07 07:41:06 EDT 2006 | Bubba
Check for coplaner leads if this just exists at reflow process, i.e. look at part before oven, turn on 3D at placement machine. If you see after wave solder, the wave could cause coplanarity issues on top as well if you are going slow enough to refl
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