Electronics Forum | Fri Nov 22 17:55:39 EST 2002 | robertorre
Your problem may be related to different aspects. 1. Oxidation on landing pads. 2. Either high(To long over liquidous temp) or low temp. 3. Bad solder (not enough vehicles) Run this test: Set a hot plate to 220 degrees C. Make sure you have proper ve
Electronics Forum | Wed Nov 06 12:56:10 EST 2002 | slthomas
What I'm seeing is an occasional pattern of tear drop shaped features in a sea of nice shiny solder. The little islands don't really have any relief.....it's more of a surface finish feature than a 3-dimensional feature. The wetting angles are good,
Electronics Forum | Thu Nov 07 12:51:09 EST 2002 | slthomas
This is embarassing. I've used ipa (actually "70/30 rubbing" alcohol) to clean these for a better view (this is a no-clean), and found the above described anomaly to be intact. So, I assumed it was something in the solder itself. Well, today I us
Electronics Forum | Wed Nov 06 20:18:30 EST 2002 | davef
cvrgrrrl Your first thermal cycle with imm silver should be the easiest to solder. That you see copper indicates you did no soldering, got no wetting, produced no intermetallics, etc. Tell us again which components did not solder? Wuzzis "plug" t
Electronics Forum | Wed Nov 06 16:31:59 EST 2002 | slthomas
I would also consider paste control (don't take it personally...I always have to get after people about this one), time on the stencil, time between print and reflow, solderability of the component leads, paste volume (that one really got us once....
Electronics Forum | Thu Nov 07 09:23:05 EST 2002 | russ
What would the considerations be in utilizing a type 4 paste as opposed to type 3? We have an assembly that has a large amount of uBGAs (12 mil diam pad)along with 50 mil pitch BGAs assorted fine pitch etc... We are experiencing difficulty in paste
Electronics Forum | Fri Nov 08 05:08:28 EST 2002 | zolasteven
Can anyone advise on the following : 1. Insufficient pcboard support during printing We are printing on double sided pc boards (approx. 8 ins by 6 ins). There is a problem of high paste when we are printing the second side. The reason bsing the boa
Electronics Forum | Fri Nov 08 11:37:44 EST 2002 | jonfox
1. Back in the early days of consumer digital cell phones, we ran into the same problem. PCB with 2000 parts in a 5"x2" area, and double sided. We ended up using our standard vacuum tooling for the NIC side and stiff ESD safe foam for the NAC side
Electronics Forum | Mon Nov 25 20:57:23 EST 2002 | Kermit
Thanks to everyone who has responded so far. We are going with dedicated tooling for our phone cards but not for our system cards so that takes that out of the equation for the former, will evaluate for the system bds.. Thanks for the info.. Regard
Electronics Forum | Sun Nov 10 08:23:02 EST 2002 | davef
Organized or not, it is very easy to end-up with a bag of "fly shit" after sweeping the floor. Making measurements: * Search the net on "capacitance meter" to find an equipment supplier. HP [Aligent?] and IEC make very good meters. [We just use a F
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