Electronics Forum | Thu Oct 28 11:50:11 EDT 2010 | phase1
We are having a little trouble with what appears to be a crystalization between our fine pitch parts. The problem appears after a a thourough wash of the pcb when dry. It looks like lead wiskers/haze between the joints.We are using water soluable lea
Electronics Forum | Sat Jun 18 00:35:15 EDT 2005 | mskler
Thanks to all. I am working on your suggetions will get back as the problem solved
Electronics Forum | Thu May 18 12:00:42 EDT 2006 | jdengler
I think he edited his original post.
Electronics Forum | Thu May 18 11:16:16 EDT 2006 | russ
Go 5 or 6 mil thick with stencil, i am not familiar with that pitch but I would recoomnd a 5mil. Was the thickness in this post before and i missed it? Russ
Electronics Forum | Thu May 18 09:18:33 EDT 2006 | Chunks
Hi dwelch123, 8 mils seems a bit thick to me. I would normally go 6 or 5 mil for fine pitch such as this. One other area to check is the the snap off. Are you using the slow snap off or just lowering the board right after print? If so you should
Electronics Forum | Thu Jun 16 09:13:46 EDT 2005 | russ
We use a 5 mil for 16mil pitch QFPs, Make sure that the stencil has been polished. Type 3 paste. We have used lead free no-clean, lead no-clean, and water soluble lead pastes for these packages. We set the printer for a slow stroke .7 in/min. wi
Electronics Forum | Thu May 18 10:20:55 EDT 2006 | slthomas
Russ asks good questions and I think Chunks pretty much nailed it. Aspect ratio (aperture width/stencil thickness) s/b 1.2 minimum (I like 1.5 if I can get it). If your aperture width = lead width (.008"), yours is 1. Tough to get consistent paste r
Electronics Forum | Thu Jun 16 00:24:29 EDT 2005 | mskler
Hi everybody, Can some body tell me that what stencil thicknes is required for the 16mil QFP. I am getting bridging as well as dry at QFP pins. What type of solder 1. Viscocity 2. mesh size 3. flux contents Should be used for this type
Electronics Forum | Mon Sep 08 09:59:56 EDT 2008 | vladig
Here we go with another "solderability problem". How do you know the pads on the bare PCB are oxidized? Just based on its colour? If that is the root cause, then why ohter parts on the same board are fine? If you want to solve the problem, get it's
Electronics Forum | Wed Sep 10 10:49:23 EDT 2008 | slthomas
You missed my point. People often don't find the need to post their problems here to begin with because "knob turning" solved them *before* they needed to lean on the collective experience of SMTnet, Technet, or what-have-you. Your posts seem to b
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