Electronics Forum | Wed Aug 17 13:57:27 EDT 2005 | ppwlee
We have encountered what appears to be mask discoloration after wave soldering. The areas of concern coincide with the areas that were exposed selectively by fixtures during wave soldering, dominated by one date code of PCB with a slightly different
Electronics Forum | Mon Nov 10 09:03:47 EST 2014 | rgduval
I can't claim to be an expert....I've just bought a used RPS, and it'll be my first...but, after reading through their manual, and working on setting things up, I'd say: -Conceptually, I like the idea of moving the board rather than moving the entir
Electronics Forum | Wed Apr 13 12:10:47 EDT 2022 | winston_one
Hello! We have a strange effect. Some pads of big trough-hole DDR slot just dessapear. Initialy it was soldered with selective soldering process (leaded, 290 degrees, ImSn finish, very short storage). Then some connectors with poor barrel fill we hav
Electronics Forum | Mon Apr 18 12:39:57 EDT 2022 | winston_one
Thanks for all comments. Process was adjusted normally, problem was in PCBs. Microsection of bare boards confirm that the copper thickness in troughholes was unsuffient, sometimes below 10 microns, on soldered boards where there were a problems durin
Electronics Forum | Fri Apr 15 09:56:17 EDT 2022 | winston_one
Thank's Dennis. I'm also now think in this direction. Process was adjusted and soldering are good. But one from five boards can have this effect with bubbles and strange uneven distribution of solder inside the barrel. Probably copper is too thin and
Electronics Forum | Thu Apr 14 15:27:05 EDT 2022 | ppcbs
If it was ROHS I would suspect copper migration. In my experience an acceptable copper finish should last up to at least 6 reflow cycles. If you have bubbles or blow holes in the solder joint, that is a sign of voids in the walls of the copper barre
Electronics Forum | Wed Apr 13 21:17:18 EDT 2022 | stephendo
If it was ROHS, I would say that the pads are definitely dissolved away. And it sounds like that is the case here. Your best bet is if it is class 2 and the barrels are at least 50% then push for them to be accepted. If you are trying for more barr
Electronics Forum | Thu Apr 14 14:00:44 EDT 2022 | winston_one
Also at few boards we see excessive voiding, extremily excessive. During solderind some bubbling can be observed near the soldering point. Boards was dried before assembly. May be we have a problem with too thin metallisation - that's why poor adhesi
Electronics Forum | Thu Apr 14 13:49:34 EDT 2022 | winston_one
Thank you for reply, Stephen. No, As I wrote it was leaded process. I heard that it is possible with lead free solder at higher temps an dwell time. At NPL Defect Database I've find this case wich looks exactly the same: http://defectsdatabase.npl.co
Electronics Forum | Mon Apr 18 12:14:39 EDT 2022 | proceng1
As far as hole fill, as was stated above, class 2 only requires 50% up-fill. In order to get better up-fill on the initial pass, you may need to consider more pre-heat. Also, better application of flux. Are you using a drop jet, or a spray? You
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