Electronics Forum | Wed Jan 05 17:56:30 EST 2011 | ppcbs
I am looking for a No-clean or water soluble solder paste, Sn63/Pb37 alloy, 15 - 25 microns (T5). I need to print with a 4.8 mil stencil opening. Does anyone know where I can get 250 to 500 grams in one week or less?
Electronics Forum | Thu May 29 16:14:34 EDT 2003 | steves
What is the general feeling in the industry on the use of 15.7 mil QFP's? Are most people shying away from them in favor of BGA or do most people consider 15.7 mil to be "standard" technology these days? What special considerations are involved? Ste
Electronics Forum | Wed Jun 04 05:13:09 EDT 2003 | emeto
Hi Pete I agree with all that. But his question was "Are most people shying away from them in favor of BGA or do most people consider 15.7 mil to be "standard" technology these days?" So, the truth is people use both.QFP has advantages and disadvanta
Electronics Forum | Thu May 29 16:29:09 EDT 2003 | swagner
I do not recommend using a HASL finish, you will have a very tough time printing repeatably.
Electronics Forum | Mon Jun 02 04:17:39 EDT 2003 | emeto
Hi Steve, Why are you so concerned about QFP(0.4) or BGA? If your equipment can manage, what's the difference? If you are designer do it better and use the cheaper or smaller package(you decide). If not use machine with vision recognition and your pr
Electronics Forum | Mon Jun 02 09:38:12 EDT 2003 | pjc
yo Evt, ".., what's the difference?". Answer: Huuuge!! between running 0.4mm pitch QFP and a BGA of same I/O, in terms of handling, storage, feeding (trays), p&p, inspection, test, rework, etc.......
Electronics Forum | Fri May 30 20:54:53 EDT 2003 | jonfox
Conversion refresher: 1 inch = 25.4 mm 1 inch = 25,400 microns 10 microns = 0.3937 mils 10 microns = 0.010 mm so 0.4mm = 400 microns and for s/n/g: 1mm = 3.240783e-20 parsecs (pc) Have some fun with that one!
Electronics Forum | Tue Jun 03 06:29:43 EDT 2003 | mk
Orrrrrr, you could eliminate the printing, shorting, and special surface finishes by bringing the boards in with the paste already on them. There is a process that is a much more forgiving method for applying paste called solid solder deposit. Check
Electronics Forum | Fri May 30 18:57:44 EDT 2003 | russ
We place a large amount of .4mm (what is that in microns?)QFPs every day. I would much prefer a BGA package. Reasons are 1. Pitch is greater which provides a larger process window 2. Alignment is easier because you don't need vision for BGA if you
Electronics Forum | Tue May 25 12:59:37 EDT 2004 | gregp
Mils to MM is actaully English to metric. 1 mil is equal to 1 thousandth of an inch (0.001")or 0.0254mm so... 12mil pitch qfp is 0.012" or 0.3mm 15mil pitch qfp is 0.015" or 0.4mm 20mil pitch qfp is 0.020" or 0.5mm (Numbers are rounded)
