Electronics Forum | Tue Aug 21 21:39:19 EDT 2001 | davef
1) why is No-clean (NC) the preferred process, for BGA mounting by SMT? Probably the same reason NC is the preferred process for mounting non-area array SMT components. 2) why is water-soluble (WS) not a hot choice? There�s not reason not to use
Electronics Forum | Mon Jan 16 16:19:22 EST 2006 | davef
Dunno. 4% higher standoff results in 16% higher reliability [�The Effects of Solder Joint Voiding on Plastic Ball Grid Array Reliability� Banks, Donald R., et al.; Proceedings of the Technical Program - Surface Mount International; September 10-12,
Electronics Forum | Tue Mar 13 11:50:21 EST 2001 | gsmguru
Here is some general things I usually ask myself when having trouble with BGA's What type of BGA ? Pitch/Bump Dia etc. Smaller bumps sizes & tighter pitches require more attention. This also impacts stencil aperature design & paste selection. Was
Electronics Forum | Thu Feb 04 10:00:26 EST 1999 | Terry Burnette
| I'd like to find some technical papers on the reliability of reworked BGAs. If you know of any, please let me know. | | I have a concern about this because our current rework process does not apply solder paste to the pads prior to placing the pa
Electronics Forum | Mon Jan 16 12:19:55 EST 2006 | russ
Dave, Why does standoff height affect reliability?
Electronics Forum | Thu Sep 22 14:25:13 EDT 2011 | hegemon
Dave has stated the caveats well. I too have similar experience in reworking BGAs that mirrors your own. The only situation where I saw this as an issue, was in memory devices where a row of BGAs might share a commonm heatsink. In those cases the
Electronics Forum | Wed Apr 27 12:26:49 EDT 2005 | jdumont
Square you say? Wouldnt this give less paste deposition than a circle and basically reduce the standoff height the same as making the pad bigger? Would using a type 4 paste for this size stencil aperture (.013") be a good idea? Thanks JD
Electronics Forum | Tue Apr 13 19:50:53 EDT 2004 | Dreamsniper
Thanks. That's a good Idea. But question. Can a cleaning equipment (aqeous cleaner design for low standoff height parts) be able to clean my PCB given that the PCB sat in our production floor for 1 week prior to cleaning? Will the flux stick hard ont
Electronics Forum | Thu Mar 28 13:19:14 EDT 2019 | davef
There is no industry standard for BTC stand-off height. "IPC-7093A Design and Assembly Process Implementation for Bottom Termination SMT (BTC) Components" just finished "Final Draft for Industry Review" in December 2018. It mentions stand-off height
Electronics Forum | Mon Jun 19 09:47:23 EDT 2017 | georgetruitt
You have a lot to think about! What does the flux manufacturer recommend as far as specifics like water temp or pressure? Do they recommend high temp di-water a detergent or saponifier? Do you currently have a cleaning machine, batch cleaner or inl
