Electronics Forum | Mon Nov 12 10:57:36 EST 2001 | emmanuel
We are to use a PBGA 272 and a PBGA 388. Between 500 and 750 thermal shocks (-45�C/+125�C), we have noticed that some cracks appear in the solder joints. According to our component specialists, these cracks are due to the whole design (pcb, component
Electronics Forum | Thu Jul 22 22:57:14 EDT 1999 | Earl Moon
| Does anyone have any experiences with bga reballing. | When I had reworked failed bga part with new part It was good. | So I tried to reball bga detached but failed . | I guess the cause of fail is thermal shock. | IS IT OK TO REBALL BGA PARTS
Electronics Forum | Fri Jun 15 12:12:34 EDT 2007 | realchunks
Hi Ed, It all depends on more info needed. How many preheaers do you have in your wave? One, two, three? Are you talking bottom side preheat? What size boards do you run and what type of parts are on it. Typically, preheat does several things; w
Electronics Forum | Tue Sep 08 15:11:26 EDT 1998 | Mike Demos
Rich: In my experience, I have seen three cases of SMT Capacitors cracking: 1. Due to thermal shock when entering the wave solder. Note that these were 1210 package sizes on the wave solder side of the boards. We were able to trace this back to th
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 | Thu Mar 04 12:34:48 EST 2004 | cyber_wolf
I know that many smaller companies clean their stencils the same way you do. If you get good results cleaning your stencils this way then I would say stick with the alcohol/wipe method. Take your stencil and put it under a microscope.If the aperture
Electronics Forum | Thu May 22 16:52:39 EDT 2008 | tonyamenson
Indium got back to me with the attached PDF. I always assumed, that in order to avoid thermal shock, there could not be any more than 80 degrees C difference between the solder pot and the pre-heated board. However, it would seem that any thing le
Electronics Forum | Tue Jan 30 01:06:51 EST 2018 | dgassier81
Hi, In our shop we've always baked out PCBs and moisture sensitive parts prior to electronic assembly using a gentle ramp rate of 2 degC/minutes going hot (93degC) and same ramp rate going cold (back to room temp). We're trying to outsource that pro
Electronics Forum | Wed Aug 14 18:17:32 EDT 2019 | slthomas
We are down to the last few unresolved PCBA test failures in a work order and scrambling to get them repaired and into a mechanical assembly. What we have found in quite a few of these cases are cracked 1206 MLCCs. The failed parts are all the same
Electronics Forum | Wed Sep 20 15:51:19 EDT 2000 | John
We are considering retrofitting our Vectra wave soldering machine with a hot air knife. I've run our problem board on a machine with this option and it does seem to work; however, there is a concern of component failure due to thermal shock. Is thi
