Electronics Forum | Thu May 31 22:35:23 EDT 2012 | jacktan
I have encountered PCB delam issue with high density PCB. PCB has 42 layers , 5 mm thickness ,laminate material is NelcoN4000-13EP,Tg 210C and Td 350C. Have pre-bake at 125 c for 12 hrs before assy.My reflow temp is standard with 243 peak and TAL is
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 | Wed Oct 19 07:04:06 EDT 2022 | winston_one
If any changes in design is not possible and you have to solder it, it's a real headache, I know... I see only 3 options here that you can try consiquently: 1) Accurately profile the board and optimize a profile (go to lower limit of process windo
Electronics Forum | Fri Jan 21 14:51:08 EST 2000 | Dave F
Mike: I�d hate to see you making design decisions, based solely on the discussion here, but that this would be an impetus to consult IPC-D-279, "Design Guidelines ... " and take a course on designing reliable boards. Werner Engelmaier (Engelmaier
Electronics Forum | Mon Dec 19 07:29:30 EST 2005 | jax
Tg is just a way to say when the board goes limp... or a quick way to rank laminates... who cares. For lead free you want to look at Td, Decomposition Temperatures. ( Temp at which the material weight changes by 5% )
Electronics Forum | Wed Feb 02 22:10:30 EST 2005 | T2
Higher Tg values are only one thing to look out for. Two other things that are very important to watch are the Td or Decomposition Temperature (the temperature that the epoxy actualy starts to break down), and the CTE for the material. Some Tg 14
Electronics Forum | Sun Aug 08 11:15:32 EDT 1999 | Earl Moon
| | Mike, | | | | Got your message and those of others concerning PCB fab supplier evaluation and qualification check lists, etc. I have a severe problem here in WI as I can hardly access the internet, and when I do it is cut off abruptly for no goo
Electronics Forum | Fri Oct 27 11:17:41 EDT 2006 | MFG CAVEMAN
Since I didn't see it mentioned - Are you specifying a laminate that is considered compatible with a RoHS process? I don't mean just a high Tg but a high Td (decomposition) and CTE material such as Isola 410, FR408 etc.
Electronics Forum | Wed Jan 11 12:37:06 EST 2006 | Amol Kane
Hi all, hope everyonein the forum id doing fine and working diligently toward RoHS capability. One of my customers have asked me (my company) to recommend a lead-free laminate. us being a CEM, have no idea of design variables (df, dk etc., (process v
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
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