Electronics Forum | Fri Nov 22 16:19:45 EST 2019 | davef
I'd guess ... + Pads have no solder mask, clear or otherwise. + Pads won't take solder, because you're trying to solder to nickel. + Nickel on the pads is oxidized and is sticking out its tongue at the flux you're using. + Something went south
Electronics Forum | Fri Nov 22 05:04:07 EST 2019 | SMTA-Matthew
We have some circuit boards where the solder mask seems clear instead of green on top of some of the tented via pads. No gold deposited during the ENiG process and no solder sticks to it but why is it clear and does it have any correlation to the thi
Electronics Forum | Fri Apr 29 14:16:16 EDT 2011 | ppcbs
Below is the long explanation. This defect is most commonly found with BGA components, but can arrise with all components. I see it happening more now with lead free boards that are being assembled with a no clean flux. Best short term remedy is t
Electronics Forum | Fri May 13 14:08:39 EDT 2011 | eezday
This appears to be black-pad and is often the result of using specs that call for gold plating that is too thick. The black pad is corrosion that is created between the gold and electroless nickel during the gold plating process. This is counter in
Electronics Forum | Tue May 03 21:14:19 EDT 2011 | davef
Can we talk some to better understand the scope and breadth of the problem? * From your picture, it looks as if the problem shows-up on some pads, but not others. Is this accurate? * Is this lot related? * Is this related to a few items from a lot? *
Electronics Forum | Thu May 05 01:21:42 EDT 2011 | city4497s
Hi Davef The problem shows up on * random location including component pads * all PCB and different PCB supplier * different solder paste lot * both printing and dispensing process * all production shift * we have only 1 production line It black,
Electronics Forum | Thu May 05 08:14:45 EDT 2011 | kahrpr
Where black pad exists, it is not a common problem. When I read it is totally random I doubt that. You have defiantly something going on that is unique with the process. It is either your board manufacturer or your solder paste or your profile. It c
Electronics Forum | Tue May 20 07:55:27 EDT 2014 | andrzej
Hi, I am facing an issue with PB-free HAL on our boards (270 pcs of 800pcs lot). I look for a root couse for this issue and I guess it is strongly related with PCB manufacturing process. In attachment you can see PCB with dark pads. They turned grey
Electronics Forum | Thu Dec 26 17:13:43 EST 2019 | rgduval
Doesn't really look like no-clean to me...typically, no-clean encapsulates the solder joint after reflow, trapping any organics. This looks like plain-old water soluble flux, that cooked a bit too much in reflow. As you noted, it cleaned up with
Electronics Forum | Wed Jun 18 20:27:28 EDT 2008 | davef
No, we not sure if your solder mask is LPI. The article we linked was aimed at solder mask application methods. LPI is the most common mask in use today. So, what kind is it? Green tells you nothing. Solder mask can be a variety of colors.
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