Electronics Forum | Wed Jan 07 17:34:52 EST 2015 | duchoang
Customer puts our board to thermal test. Test cycle is -55c to 85c, repeat cycle in 15-20min. After 600 cycles, lot of TSOP joints are cracked, leads lifted. There are reasons such as thin PCB, mechanical impacts, warped PCB... My question is, how lo
Electronics Forum | Thu Feb 03 21:17:07 EST 2000 | Dave F
AF: Unfortunately, there is no "acceptable number of cycles" either in air-to-air and one liquid-liquid thermocycling, nor interconnect stress testing. There can be a "minimum threshold" that would assure no failures as the result of the assembly p
Electronics Forum | Wed Jun 21 11:09:37 EDT 2006 | samir
Muse, I agree. There has been much debate but the previous scenarios discussed in the forum have been regarding the SAC/RoHS BGA and Sn-Pb paste. I have successfully collapsed a SAC BGA with a Sn-Pb paste using the "hybrid" profile that Amol refers
Electronics Forum | Tue Jul 26 08:20:46 EDT 2005 | Bob R.
All you can do is try it. I did a literature search last year on causes of BGA voiding and came up with a pretty long list, sometimes contradictory. I also discussed it with several paste suppliers. What I came away with is that what aggravates voi
Electronics Forum | Fri May 15 21:09:14 EDT 1998 | Steve Gregory
| | If you have a chance check out the MSD artical (Page 69) in April Electronic Packaging & Production. It is one of the worst articals with unsubstantiated conclusions I have ever seen. Notice Figure 3 on page 72, Caption indicates two simular co
Electronics Forum | Fri Jul 08 16:35:04 EDT 2005 | Jason Fullerton
"Whether or not you need a toe fillet depends on your application. We have high reliability products where we can't use a QFN over a certain size, regardless of toe fillet. We have other applications where we meet the thermal cycle requirements for a
Electronics Forum | Fri Apr 20 07:54:25 EDT 2007 | Bob R.
I'm in the high reliability (exempt) sector and have thermal cycled hundreds of boards in the past few years. As far as which is more reliable, SnPb or SAC305, my data is similar to what the technical literature is saying, "It Depends". In low stra
Electronics Forum | Tue Aug 08 20:43:41 EDT 2000 | Dave F
Tom: So is warp or is it twist? They�re different problems, possibly with different sources!!! And possibly different solutions!!! Consultants to talk to are: Earl Moon (pod@vcn.com), Werner Engelmeyer (engelmaier@aol.com), Les Hymes (les.hymes@w
Electronics Forum | Mon Dec 31 08:51:58 EST 2001 | davef
Warp depends on: * How close the board gets to its Tg during the solder cycle (the closer you get to the Tg the worse the warp gets) * Amount of copper on each side and the balance between the two * Thickness of the board * Overall length x width * T
Electronics Forum | Thu Feb 03 10:22:23 EST 2000 | AF ng
Dear Dave, Thank you for your reply. What I meant thermal excursion is the solder cycle. That is for the same particular point, how many time we can solder them, for FR4 boards. Thank you
