Electronics Forum | Sun Aug 24 15:00:46 EDT 2003 | Handsome zhang
I am placing a plastic Cypress, 256 pin BGA on a > small assembly, and I cannot stop the corners > from bowing. I've moved my profile up and down > with no results. Any suggestions? Hi mike I am a staff of smt in ASUS(TAIWAN),I have a large in
Electronics Forum | Mon Jun 07 17:58:12 EDT 2004 | Rob
UPDATE: Just for fun... I sacrificed a scrapped board to determine what remained and what fell and this is the result. Board dimension was 18"x9" and .9" thick. Components consist of hundreds of passives plus 386 proc (QFP256), TSOPs, SOLs 14/16/20,
Electronics Forum | Wed Jul 28 00:13:03 EDT 2004 | NTV
We are seeing un-Reflowed paste along the IC > leads. There is only a very small amount imbedded > in the flux, typically there is about 10 beads > per lead. But on most leads. We are using > no-clean Kester 256 paste (Easy Profile)We have > not
Electronics Forum | Tue Jan 11 11:08:03 EST 2005 | clarkk
Hello, We are assembling a large pcb with 256 Lumex #SSL-LXA228SRC-TR31 SMT LED's on an HSP 4791. The part I'm using for the library is a modification of an existing SMT LED from the standard library. The problem is that the HSP rejects about 30% of
Electronics Forum | Wed Mar 30 19:54:36 EST 2005 | mattkehoe
We've already done it for a customer. We used 63/37 ssd's on the top side where the are a few caps and one 256 pin QFP, coated with adhesive flux to hold the component, and lead free un flattened ssd's on the bottom to be attached to the other boar
Electronics Forum | Thu Nov 03 10:33:04 EST 2005 | Samir Nagheenanajar
I've read all the SMTNet threads available on this topic, been to a couple seminars, and read some articles, and the general consensus seems to be "it can be done, but shouldn't." However, at my company, we have a Pb-Free (SAC alloy) 256 IO BGA comi
Electronics Forum | Thu May 31 19:45:47 EDT 2007 | diesel_1t
We place a QFP 256 leads 20 mil pitch, had a lot of troubles with shifted components and solderability issues. solderability is not a problem anymore; we solved with a ramp-to-spike profile with .9�C/s 'til 183� then spike to about 118�C, TAL ~60s. W
Electronics Forum | Tue Aug 14 10:01:32 EDT 2007 | gmoritz
I have posted earlier on a UIC Radial inserter machine. We have the machine running after repair of the CnC head. However, I now have a process problem with a board that has 256x3 LED parts (768 LEDs in three colors) where only 50% of the LEDs can b
Electronics Forum | Wed Sep 05 07:07:25 EDT 2007 | mun4o
hi, I have a big problem with soldering uP QFP144 package.All components in PCB are small, only this chip is big and I can't make good temperature profile.Solder joints of other components are shining and with good wetting, but in QFP leads solder j
Electronics Forum | Fri Sep 07 09:13:21 EDT 2007 | smtirl
Folks, we've recently upgraded to Heller MKIII reflow ovens with Gen 9 cooling units. We're running N2 atmosphere at 1000ppm O2 and Kester256 solder paste. We're seeing a big problem with flux residues building up in the cooling section of the
