Electronics Forum | Fri Apr 13 02:55:47 EDT 2007 | raychamp007
Davef, Thanks for your reply. Also sorry because I didint notice your ealier reply on http://www.smtnet.com/Forums/Index.cfm?CFApp=1&Message_ID=48991 regarding the normal gull wing lead, the solder fillet must extend to the mid point of outside lead
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 | 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 | Wed Nov 06 15:47:49 EST 2002 | bpan
Hello All, Having a problem during reflow and would like your opinions. We are using Kester r562 water soluble paste and I am using a Kic 2000 profiler in a 4 zone oven (top only). We are seeing poor wetting or fillets that are not "passable" per IPC
Electronics Forum | Fri May 26 04:58:19 EDT 2023 | auriga2001
I agree with the two other replies. Left alone, it is a defect. If it's just excess adhesive or coating, you can use IPC-7711/7721 'Rework, Modification and Repair of Electronic Assemblies' for guidance on removing. Section 2.3.1 explains how to te
Electronics Forum | Thu Aug 23 16:41:06 EDT 2001 | slthomas
Naw, the rest of the BOARD we use them on. Same assembly. Actually we use them on one other assembly and have the same problem. Same oven, same line, same paste, same problem. I've tried to get the production super. to move them to another line w
Electronics Forum | Thu May 09 22:32:50 EDT 2002 | ianchan
Hi Guys, thanks to everyone for their help and advise! we are running these LCC parts in the 1000's, so its going to pose a big problem to either: 1) tin-plate the oxide layer, 2) HCL away the oxide layer, thanks for the option shown, dun think so
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 | Tue Nov 05 09:57:45 EST 2013 | cuperpeter
Hello All, We have a problem with dewetting of solder paste. Problem is most visible on the pads without components (see attached pictures) and occurs randomly, 20% of PCB's. Pcb supplier sent us a cross-section of pads with thickness of Cu, Ni and
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,
