Electronics Forum | Fri Jan 07 07:36:14 EST 2005 | dansmall
I have a Polyimide board that is showing signs of de-lamination. I was wondering what pre-bake times and temperatures other people would recomend for new boards as well for boards that have been on the shelf for 8 months.
Electronics Forum | Sat Jan 08 08:50:35 EST 2005 | davef
Normally, you should not have to bake boards that are properly packaged and stored. Since you are seeing problems, baking makes sense. Consider 125C for 4 to 6 hours. Additionally, look here for more, while waiting for others: http://www.smtnet.
Electronics Forum | Wed Jan 12 10:05:20 EST 2005 | Dreamsniper
we are using polyimide boards 6 inches x 7 inches, 2.5mm thick, 12 to 14 layers, for aerospace industries. I am using a long bake of 12 hours at 70'C prior to manufacturing or exposure to elevated reflow and wave soldering temperature. If schedule i
Electronics Forum | Fri Oct 04 11:34:42 EDT 2002 | Bob Willis
Some additional comments from a paper may be of interest. Baking Printed Circuit Boards - Why and How Baking printed boards prior to conventional and surface mount assembly should not be necessary. Often boards are baked for historical reasons; in
Electronics Forum | Wed Dec 22 18:09:07 EST 2004 | kmorris
At a previous job I had been taught that when reflow soldering polyimide flex circuits, it was necessary to pre-bake them before reflow soldering to prevent delamination. Our procedures said that there must be a 1hr bake prior to reflow, and the flex
Electronics Forum | Wed Dec 22 19:09:17 EST 2004 | rohman23
Very strange...I just logged into the internet to come post this very question for all the lurking experts. We have a 16 layer rigid-flex that we have never baked. Our board vendor is expressing concern that we do not perform a pre-bake before assy
Electronics Forum | Fri Oct 01 09:47:36 EDT 2010 | noid
Yes, they should be baked prior. We pre-bake all polyimide fabs, flex or not. They are prone to delam.
Electronics Forum | Wed Dec 22 21:14:53 EST 2004 | davef
IPC-FA-251 recommends 121*C for 30-60 minutes for 1 and 2 flex layer circuits. A rigid flex can take easily an hour per layer depending on the construction.
Electronics Forum | Wed Jan 05 17:53:52 EST 2005 | SuePH
We had a contract in house that included a flex board which required an 18 hour bake at 105 degrees. The other brds got along fine with 2 hours, but the flex board would delaminate until we went to this long bake. I don't know how the engineer came
Electronics Forum | Wed Dec 22 23:29:57 EST 2004 | KEN
Check with Dupont's web site. They have a wealth of information on the various polyimide products they manufacture. I was quite surrised at the differences in materials and in particular the dimensional stability and hydroscopy. Good stuff mayna
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