Electronics Forum | Mon Oct 15 10:51:49 EDT 2001 | davef
On over printing, the general issues are: * Paste deposits being so large that when reflowing, collapse onto many, rather than a single solder mass. * Paste expanding during heating and being close to other solder deposits and bridging [as you say].
Electronics Forum | Tue Apr 13 13:45:26 EDT 2004 | arcandspark
Ken you say reaching 218 to 221 C will give a homogenus solder ball. The pb free solder balls on the BGA reflow at 235 C to 238 C but I have seen when you combin to differnt types of solder say 63-37 and 10-90 you will atually lower the melting point
Electronics Forum | Mon Feb 10 16:59:57 EST 2014 | hegemon
It is sort of a self answering question if you come in from the solder paste angle. First....start gathering data. Check every day, or every new paste jar, for: Storage conditions (temp), paste expiration date, ambient temp and humidity where yo
Electronics Forum | Wed Aug 19 16:28:03 EDT 2015 | mdeley
Looking for a Santa Clara area contract service with capability to attach 15mil dia. solder coated Cu balls, ideally on a 12" x 18" PI panel, small job to start. T&R services are a plus. My initial search is coming up with device/component level r
Electronics Forum | Fri Dec 03 18:17:12 EST 1999 | Dave F
Dave: There's lots of stuff on the web describing BGAs. Examples are: http://www.smtnet.com/bookstore/publications/0speckdo1/s1.html http://www.smtnet.com/bookstore/publications/0shutcco1/ch1p2.html http://www.citizen-america.com/OEM/bga/process
Electronics Forum | Wed Sep 08 17:49:19 EDT 2004 | gregoryyork
Knock off some balls and you may find it has a flat bottom to it were it has mechanically stuck to the solder resist usually seen under 60X magnification. Common with Liquid photoimageable resist (I know again) Best way to check resist cure is to pay
Electronics Forum | Thu Aug 01 13:10:46 EDT 2002 | johnw
Chris, I don't know what machine your using, but we're also playing with one at the moment and don't see any problems with micro solderballing as far as I'm aware (I'll double check tomorrow thou!) We're using Kester 977 with it and don't have a pro
Electronics Forum | Thu Dec 27 11:05:40 EST 2007 | realchunks
5 or 6 mil thicjk stencil and no reduction.
Electronics Forum | Fri Dec 28 17:02:04 EST 2007 | davef
We agree with Chunks
Electronics Forum | Mon Jun 03 11:51:44 EDT 2002 | Troy
A 50KV machine will allow you to see solder bridges and balls under the BGA. It will also allow you to check placement and can "see" through the metal housing. If you want to inspect for voids, then you what to look at equipment in the 100KV range.
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