Electronics Forum | Thu Apr 09 14:02:29 EDT 1998 | Earl Moon
| | I am currently involved in a reliability project related to SMT QFP and TSSOP fine pitch solder joint reliability. I have decided to use a temp chamber for stress testing. Is there a test standard that covers this? I am also a bit unsre as to whe
Electronics Forum | Fri Apr 10 20:27:07 EDT 1998 | Jean-Paul Clech
| I am currently involved in a reliability project related to SMT QFP and TSSOP fine pitch solder joint reliability. I have decided to use a temp chamber for stress testing. Is there a test standard that covers this? I am also a bit unsre as to wheth
Electronics Forum | Wed Dec 31 10:09:27 EST 1997 | Ken Daniels
| Has anyone had any experience with thermal shocking | and cracking of SMD capacitors during the rework process? | My company was advised to preheat capacitors to 125 C | at a rate of 2 C/sec before replacing them onto boards. | Would this maybe
Electronics Forum | Tue Apr 13 08:21:05 EDT 2010 | esca
Hi manchella, After ATC test, two different failure modes can be present: solder FATIGUE (into bulk) or BRITTLE INTERMETALLIC fracture. So, first you have to verify this. Moreover, which brand of SMT paste have you used ? The crack into solder joint
Electronics Forum | Thu Nov 29 16:00:03 EST 2007 | jmelson
Desoldering often applies a LOT more heat and thermal stress to the part, and maybe mechanical forces while everything is hot, to get the part free of the board. So, a lot of damage might be done there, making post-mortem harder. Without the leads,
Electronics Forum | Fri Jul 15 13:58:32 EDT 2005 | seaK
Our production is putting QFN40 and QFN56 package on board. With 80% opening on terminal, 40% on thermal pad, we found QFN56 100% forming toe fillet, but it does not work out the same to QFN40. We suspect it's because of the weight of component.....
Electronics Forum | Mon Jun 01 16:48:16 EDT 2009 | stevezeva
Mika, Have you ever worked with a 3-row I/O QFN? QFN180 to be exact? Steve
Electronics Forum | Tue Nov 18 11:35:43 EST 2003 | John
Does IPC list a specification that describes the acceptable thermal stress capabililty of components? I seem to recall something about dipping at 260C for 10 seconds, but I can't find the reference. Also seem to remember descriptions of the allowab
Electronics Forum | Fri Dec 30 11:54:53 EST 2005 | John S.
Seen cap cracking before. It can be caused by thermal stress as noted above, but don't discount mechanical stress and handling. Your depanelization method is a strong candidate. We applied strain gages to baords and benchmarked various mechanical
Electronics Forum | Sun May 19 23:38:57 EDT 2013 | shrikant_borkar
We are EMS. Later revisions and Other models are get Modified. Now we have some remain Stock of Pcbs abd there end also. We have taken trial with Reduction in Apparatuses. But even small amount of solder paste at thermal Pad is causing QFN lift up.
