Electronics Forum | Thu Sep 29 19:18:24 EDT 2005 | HLy
Hi, I noticed that the solder joints on my BGAs end up with a lot of wrinkles after reflow. See picture at: http://pstr-r02.ygpweb.aol.com/data/pictures/02/01A/17/DD/E3/9E/n8BhepQLFDs6GMSwaRNxPCTWR5NdpUJZ0300.jpg Does anybody have any ideas what cau
Electronics Forum | Fri Oct 07 09:19:54 EDT 2005 | Kris
the direction in which the solders cool in a BGA are also different than the rest of the boards as the joints " hidden" to ambient. Refer to an analogus phenomenon in the cookson application note. http://www.cooksonsemi.com/pdfs/How%20&%20Why%20Bum
Electronics Forum | Fri Sep 30 10:07:44 EDT 2005 | davef
Alternate explanations are: * Your reflow profile needs to be tweeked. * Bumps under a die look different than elsewhere on the package. Severe creases may indicate a problem, but creases of only a 0.001 to 0.002" deep should not pose any difficulti
Electronics Forum | Wed Oct 03 17:07:52 EDT 2001 | davef
We have had soldering problems with fine pitch QFP in the past [and probably will in the future]. Several questions leap to mind: * When you took your profile on the component pads, do you profile on the pads that did not solder well? * When you say
Electronics Forum | Tue Sep 22 06:07:02 EDT 1998 | jacqueline coia
need advice to point me in the correct direction for solution to the problem of unsoldered joints which look soldered under normal visual inspection, but when pull strength test is performed the leads are coming away from pad, no strong intermetallic
Electronics Forum | Mon Dec 17 11:20:12 EST 2001 | slthomas
Well, I was able to convince them we had a serious problem on the poorly reflowed boards without spending 2k on off- site analysis. Now all we have to do is sort out the ones that flowed well but had solder balls (looks like a damaged stencil prob
Electronics Forum | Wed Oct 03 21:28:38 EDT 2001 | davef
A firm grasp on the sublime. Mike points-out a good reason to describe Claude's problem as "open connections" or "open solder connections"? [Ahhh geez, wut a spoil spurt]
Electronics Forum | Wed Oct 03 17:08:32 EDT 2001 | davef
No comment or intent to appear critical on your particular situation, because you did the troubleshooting to determine the source of the problem, but �solder on the component lead, but not on the pad� is more often caused by a reflow profile that get
Electronics Forum | Fri Jul 12 22:15:56 EDT 2013 | ericrr
Sorry to build up your hopes. The latest thing to hit the air ways at work, I was accessed of fiddling with the oven settings, because there were reports of "cracked joints" there was no mention of where the cracks were, cracked at the pcb or cracke
Electronics Forum | Wed Oct 03 09:56:51 EDT 2001 | Claude Tremblay
Hello everyone We have a QFP-308 (0.20" pitch)on a board and we have a lot of opens after reflow. We checked our profil by installing thermocouples on the pads of the component and everythings seems OK. We checked the coplanarity of the leads and it
