Electronics Forum | Fri Apr 30 12:34:12 EDT 2004 | Bryan She
Hello all, these days I've met an OSP board testability issue. 1.OSP board 2.Solder paste:Kester R244 no clean paste 3.Print solder paste on test pad. Issue: There's brone(light yellow)flux residue on test pad,and the probe can't penetrate the residu
Electronics Forum | Wed Oct 20 07:09:12 EDT 2004 | mattkehoe
Not really. Our process is a solid solder deposition application so we are not placing components into the wet paste prior to reflow. We print the paste then reflow is without components, trying to create a meniscus which is then washed, flattened,
Electronics Forum | Mon May 13 11:20:06 EDT 2013 | emeto
From what I have read about the topic, recommendation is to use flux for fine pitch BGAs. Printing is difficult because of the small pads. HEre is the moment where you have to make your calculations. Do you have enough assemblies that will use
Electronics Forum | Tue Jan 31 19:34:11 EST 2017 | jgo
I have solder bumps diameters @ 80um, the board pad size @ 100um. Can this size be printed? How about dispensing?
Electronics Forum | Sun Sep 12 08:30:29 EDT 2004 | davef
Well, another alternative is to use a water washable flux. If you insist on staying with a NC flux, use one that is probable. We prefer to probe solder, rather than copper.
Electronics Forum | Wed Feb 01 02:21:26 EST 2017 | rob
80 micrometres (0.08mm) or 80 mil (2mm)? Smallest I've seen reliably printed is around 0.2mm x 0.4mm (01005 pad) and 0.2mm x 0.2mm CSP pad, not seen anything dispensed below 0.35ish, but we are not cutting edge.
Electronics Forum | Thu Dec 16 18:36:01 EST 2004 | mattkehoe
We use water soluble solder paste. When it gets a little dried out, can we add something to rejuvenate it? Liquid flux? We do not place components, just print and reflow the solderpaste so solderballs, spattering, and other issues like those are of
Electronics Forum | Tue Sep 18 19:32:49 EDT 2007 | davef
Welcome Jimmy Let's mince words to help focus on the issues. When you say "QFP area solder paste shifted," do you mean: * Paste printed on land pattern perfectly, but moves after printing. * Paste printed off the land pattern, even though the stenci
Electronics Forum | Mon Apr 16 14:33:50 EDT 2001 | dason_c
Consider to use micro via 10 mil or less, it may help to prevent any solder/flux reflow to the other side and affect your next printing operation. Also, solder void need to be under consideration. Dason.
Electronics Forum | Fri Mar 29 07:53:12 EDT 2019 | davef
Why are you printing paste on test via? In the old days, we probed soldered pads to cushion impact force of probing. Is that still a reasonable practice?
