Electronics Forum | Wed Aug 09 08:46:01 EDT 2017 | stivais
I agree. Just thinking.. could it be copper plating issue as well? anyway, would be interesting to see some photos. Sounds like solder (from HASL process, wave or even poorly washed SMT solder paste) to me.
Electronics Forum | Mon Sep 17 12:21:43 EDT 2018 | bpeay
M_, the parts may be similar but the boards look to be different. Is the thermal relief for each lead on each board the same? what is the board finish, HASL, Enig, OSP or other? The part itself may not be your problem but the part that is partial pla
Electronics Forum | Fri Nov 16 07:55:17 EST 2018 | robl
Hi Prem, We used to place millions of Nickel battery tabs using Cobar paste. We found it particularly aggressive. Just contact your local Cobar distributor and ask them for samples of their most aggressive fluxed paste. Kind regards, Rob.
Electronics Forum | Fri Nov 16 09:04:40 EST 2018 | robl
and here.... https://smtnet.com/Forums/index.cfm?fuseaction=view_thread&CFApp=1&Thread_ID=9389&#Message37375 Which was in the days of leaded, but the ROHS paste had the same flux formulation.
Electronics Forum | Wed Nov 21 05:57:30 EST 2018 | premkumar_haribabu
Hi Robl, Thanks for your qucik reply!! , i understand if we use aggresive flux that we can impove solder wetting over nickel plate vs PCB pads & we need to solder through 12 zones reflow oven. Prem
Electronics Forum | Fri Jun 07 10:46:16 EDT 2019 | gregoryyork
The Single Solder ball stuck to the mask may indicate undercured as well. The issue is not so much the mild No Clean flux but the potentially major active HASL flux or Silver Process chemistries causing issues. This has been through flow solder hasnt
Electronics Forum | Mon Jun 03 17:17:36 EDT 2019 | gregoryyork
We see it fairly widely used over in Europe but isnt a particular favourite as if it's not cleaned or prepped properly can be very unreliable.
Electronics Forum | Fri Nov 01 18:21:50 EDT 2019 | gregcr
I does depend on the level of technology of the PCB. RoHS-HASL for basic products and Silver Immersion for a flat finish, are my preferred.
Electronics Forum | Mon Jun 15 20:37:29 EDT 2020 | travishemen
Try sending your boards to rework before SMT and have them remove the excess solder from the fiducials. It usually works great until someone accidentally removes the entire fiducial.
Electronics Forum | Fri May 14 14:46:56 EDT 2021 | emeto
Not following the lead paste process window has a whole set of risks for joints quality and reliability.
