Electronics Forum | Sat Apr 18 09:44:46 EDT 2009 | davef
Low tombstone pastes have been around for 8-10 years. Talk to your paste supplier about suggestions of the "latest and greatest." Usually these pastes: * Are a blend of alloys with slightly different melting points * Have a mid-level activity flux *
Electronics Forum | Sat Apr 18 17:42:07 EDT 2009 | billwestiet
I like this suggestion the best as a "band aid", check out some of the low tombstoning solder pastes. I've seen these work.
Electronics Forum | Tue Apr 21 16:33:06 EDT 2009 | llaerum
Home plate design is great for avoiding beads and tombstoning in some cases, but it will not help you when the spacing is too far apart. It will make it worse. You need a good even screen and accurate placement.
Electronics Forum | Wed Apr 22 15:50:24 EDT 2009 | emilioescatel
Hi: I would like to know their opinion about the critical variables that I need to control in a screenprinter(solder paste aplication on PCBs) process and how I can control them. Thanks.
Electronics Forum | Thu Apr 30 13:09:53 EDT 2009 | scottp
One factor I see missing is separation speed (or snap off speed). I've run experiments with different pastes where it was the biggest factor in standard deviation of print volume for small apertures.
Electronics Forum | Thu Apr 23 15:46:08 EDT 2009 | ccross
During initial profiling we shoot for 15% or less voiding on our BGAs. During production runs we consider voids under 15% to be ok. Voiding between 15%-25% we string tag and pay more attention to during test. Over 25% we consider a reject.
Electronics Forum | Thu Apr 23 22:01:07 EDT 2009 | davef
That you have one BGA of 30 BGA that has voids, makes us wonder what's the deal with that one BGA. Especially given that this is the initial run of a product with BGA at your plant, it really makes us want to understand just what is driving the voidi
Electronics Forum | Thu Apr 23 18:40:35 EDT 2009 | nickh
Do any of you fine people have any suggestions on how to align the Fuji CP3 tape leaf sensor? The little mirrors are out of alignment, any ideas how to get them back? Thanks!
Electronics Forum | Mon Apr 27 02:44:07 EDT 2009 | michafogel
Can someone point me to a standard, if there is any, or design rule regards with preffared spacing between PTH and SMT pads for LF wave soldering process (SAC alloy)
Electronics Forum | Tue Apr 28 04:07:56 EDT 2009 | davepick
There's a nice tool on this site - http://www.enhancetechnical.co.uk/ Click on Internet Tools and then the image - brings up a useful interactive tools which helps understand influences on wave solder bridges. Dave