Electronics Forum | Thu Mar 30 08:48:37 EST 2006 | russ
So you have solder balls at the outer edge of the part right where the pad goes underneath? If so you just have too much solder but I wouldn't worry about them. the solder usually does not wet to the edges of these parts because of the exposed copp
Electronics Forum | Fri Apr 14 23:31:51 EDT 2006 | Pasofol
Have done some rework on BGAs but what kind of minimal pitches/solder balls you dealing with and what kind of volume of rework you planning to do on it? You can get a fancy one which is almost fully automated with alignment so on, others you need t
Electronics Forum | Tue May 02 15:43:06 EDT 2006 | bhall
Thank you PWH, All good points. I use a semi-automatic printing process not a screen printer so if more solder balls and beads are created then I would be creating more re-work and that is exactly what I do not want to do. I guess the best thing to
Electronics Forum | Wed May 24 13:10:28 EDT 2006 | Chunks
VIP 98, I believe that's a 7 zone if I can remember 6 years ago. Try 150, 165, 200, 235, 235 and 235 (top and bottom temps) with a belt speed of 35 inches per minute. This should get you in the ball park depending on the size of your board.
Electronics Forum | Wed May 24 19:46:32 EDT 2006 | JohnM
So, it looks like the backward compatible of BGA statement is not guarantee for solder joint reliability. It doesn�t matter what temperature and what melting sequence we have in order to avoid the solder void issue. Is Pb diffused homogeneously thr
Electronics Forum | Thu May 25 08:58:14 EDT 2006 | inds
aj, check out the link http://www.smtnet.com/forums/index.cfm?fuseaction=view_thread&CFapp=8&Thread_id=10387&mc=5 as Samir mentioned in that link, try keeping your peak temp within 220-225degC.. TAL 217 around 20-40 sec..depending on your ball d
Electronics Forum | Thu May 25 18:41:15 EDT 2006 | russ
How accurate is your placement machine? if it is accurate I would eval up to 25% off pad. the problem I might think you will have is errant paste or balls causing shorts if it doesn't coalesce completely. Bottom line is, if the board is good at th
Electronics Forum | Thu Jun 01 16:30:05 EDT 2006 | slthomas
Just wondering if anyone knows this off the top of there head. I might be able to figure out the math based on surface tension (this is 63/37 so the data is out there) but I REALLY do not want to put that kind of effort into this. :/ Editing to clar
Electronics Forum | Tue Jun 06 15:45:18 EDT 2006 | slthomas
Yep. What I'm really looking for is the minimum radius of curvature for 63/37, which is a function of it's surface tension. It's physical properties issue, not an agency issue. I've seen some references that I have interpreted to mean that it's some
Electronics Forum | Tue Jun 13 23:08:32 EDT 2006 | mrduckmann2000
WINSLOW IS NOT THE BEST CHOICE, WE HAVE TRIED SEVERAL DIFFERNET STYLES OF BGA'S WITH NO LUCK. WINSLOW HAS EVEN HAD TROUBLE RE-BALLING OUR BGA'S. THEY SUGGEST LONG BAKE TIMES, DIFFERENT FLUXES...ETC NOTHING HAS WORKED PERFECTLY. THE PREFORMS ARE B