Electronics Forum | Thu May 08 11:58:12 EDT 2003 | fmonette
Hi Chrissie, This might be old news to you but I just wanted to make sure that you are aware of all the implications of BGA rework relative to the control of moisture-sensitive components. For example, you need to keep track of the total exposure t
Electronics Forum | Wed Oct 17 18:42:37 EDT 2001 | scott
Any processes that I need to be aware of that differs from standard FR4 during reflow and wave soldering? I've read one of the problems is the thermal expansion of teflon is quite different from copper. I've also seen a "blurb" where teflon absor
Electronics Forum | Mon Sep 26 08:39:39 EDT 2005 | avalancher
Not that this actually happens anymore, but could it possibly be moisture in the PCB? Have you tried baking one or two for a couple of hours then run to see if it repeats?
Electronics Forum | Fri Aug 06 07:16:36 EDT 2004 | davef
When moisture outgasses through plating, it continues through the molten solder, causing a meak solder connection. There's another issue with thin plating that we haven't focused on in this thread. If plating is thin, the stress on the barrel of a
Electronics Forum | Thu Jun 25 15:33:51 EDT 1998 | Earl Moon
| | Hi there, | | Does any one know what is TCE for fully wet saturated FR4. I came to know that for Dry FR4 the TCE is about 15-19 PPM �C. Is that true? | | | | Appreciated for your help. | | rgs, | | chiakl | Chiakl, | It looks like you are speaki
Electronics Forum | Thu Sep 11 23:50:51 EDT 2003 | Dean
Epoxy is hydroscopic. A cavity will form when the cure furnace reaches the boiling point of water. The steam expansion creates the pocket. It can be large enough to be filled with molten solder from the wave machine and cause a hard short under th
Electronics Forum | Thu Jun 25 11:47:39 EDT 1998 | Steve A
| Hi there, | Does any one know what is TCE for fully wet saturated FR4. I came to know that for Dry FR4 the TCE is about 15-19 PPM �C. Is that true? | | Appreciated for your help. | rgs, | chiakl Chiakl, It looks like you are speaking of what could
Electronics Forum | Wed Oct 18 16:41:35 EDT 2000 | Dave F
It's unrealistic to think that two materials with the following disperant properties would have the same reflow profile. From http://www.norplex.com/Carrier.htm Physical Properties / NEMA FR-4 / NEMA CEM-1 Glass transition temperature �C / 130 / 10
Electronics Forum | Tue May 02 14:19:26 EDT 2000 | Bill Schreiber
There are two primary causes of epoxy adhesive bond failure, heat and over exposure to moisture. Ultrasonic cavitation is a only a mechanical "scrubbing" action on a microscopic level. However, if the adhesive bond is week or has small areas of det
Electronics Forum | Mon Feb 19 13:04:17 EST 2001 | billschreiber
The ultrasonic frequency used in today�s stencil cleaners is usually a 40 kHz �sweep� frequency (also used on semiconductors and other sensitive cleaning applications). This frequency is not low enough to cause stencil damage (the lower the frequen
