Electronics Forum | Tue Apr 29 07:38:42 EDT 2008 | davef
Warpage typically (not always) kinda, sorta points to a fabrication bake induced issue that is the racking technique & may be relieved by "flat baking" under weight. Your baking at 125* won't do dip. You need to get the laminate temperature above it'
Electronics Forum | Mon Jul 16 21:39:40 EDT 2001 | davef
The method you suggest is about the only way to �clean-up� this terrible situation. Realistically, this is a "memory" type condition induced by design, build symmetry, "cross ply construction", excessive cool down rates during lamination or reflow a
Electronics Forum | Thu Jun 27 17:24:17 EDT 2002 | Daan Terstegge
Never did a DOE on that, but I think it would be quite difficult to warp a board inside the oven if it was flat when it entered the machine. If there's no center-board support then it's another story, then the board will bend due to it's own weight.
Electronics Forum | Mon Dec 16 10:54:48 EST 2002 | davef
Knee of barrel and pad crack: Caused by thermal stress during soldering, because epoxy expands in the "z" 3X more than "x" or "y" which are restricted by the fiber. Related to: * Design of pads too large relative to hole diameter * Temperature at o
Electronics Forum | Fri Jul 23 02:54:47 EDT 2010 | wizzkid
I think that it can be solved by placing ths into a baking oven with the set point above the PCB Tg. For this process to be succesful, weights need to loaded onto the PCB stack during the heating cycles. Once the cycle is complete, the PCB stack will
Electronics Forum | Wed Feb 23 20:25:17 EST 2000 | Chris Wallace
Like all who post messages here, I'm looking for a little bit (well, maybe a lot of bit) of help. We're currently going through a redesign of a board which will utilize several FPGAs. The manufacturer (Xilinx) recommends using solder mask defined p
Electronics Forum | Wed Feb 23 20:25:17 EST 2000 | Chris Wallace
Like all who post messages here, I'm looking for a little bit (well, maybe a lot of bit) of help. We're currently going through a redesign of a board which will utilize several FPGAs. The manufacturer (Xilinx) recommends using solder mask defined p
Electronics Forum | Wed Mar 18 09:03:57 EST 1998 | Earl Moon
| Problem occurs because the glass transition temp for FR4 is lower than reflow temperature. Our company wrote an article which was printed in SMT magazine some years ago | that deals with this exact subject. Best way to deal with this is to use a ce
Electronics Forum | Thu Jun 25 14:41:07 EDT 1998 | Earl Moon
| Alright gentlemen and ladies of the forum, I again seek knowlage on what is probably a well known fact. I have spent a good part of the morning with various IPC standards and weighty tomes such as the Electronic Packaging and Interconnection Handb
Electronics Forum | Sat Aug 03 07:29:20 EDT 2002 | davef
IPC-PE-740 "Troubleshooting for Printed Board Manufacture and Assembly" has words to the effect of � 1.5---BAKING Laminate materials are baked several times during the manufacture of a printed wiring board. There are four major reasons for
