Electronics Forum | Sun Apr 05 12:30:22 EDT 2009 | qualityguy
Forum: Has anyone experience conformal coat peeling after HASS and the failure mechanism being low surface energy attributed to the solder mask?
Electronics Forum | Tue Apr 07 20:06:27 EDT 2009 | davef
We doubt that HASS has much to do with your conformal coat peeling. Sure, poor wicking [low surface energy] could cause the issue that you see. Here are links to a couple of good [no formulas or differential equations] articles on surface energy: * h
Electronics Forum | Mon Nov 27 13:36:41 EST 2000 | C.K.
You'd more than likely have repairability issues with the Acrylic based one. The acrylic-based finish is alot harder and more brittle versus the silicone. Some of the new silicones, you can just "peel" with your fingernail, while still getting reli
Electronics Forum | Tue Apr 07 15:36:15 EDT 2009 | gtemkin
Most of the conformal coating manufacturers recommend verifying the compatibility of their coating with the solder mask, so it's no surprise that occassionally there will be such issues. Are you sure your conformal coat is completely cured? If your
Electronics Forum | Thu Apr 09 06:28:11 EDT 2009 | qualityguy
We have different Solder mask 'gloss' and 'satin' the gloss has a surface energy =40 dynes. The test evidence to date is strong correlation between surface energy, mask type, HASS failure
Electronics Forum | Thu Apr 09 18:55:49 EDT 2009 | gregoryyork
seen it many times before when the resist is not cured at manufacturing. get PCB man to check with K type thermal couple that boards ARE in fact cured. this is normally 155C ON board temperture not oven setting Cheers Greg
Electronics Forum | Thu Apr 09 21:21:11 EDT 2009 | qualityguy
Hello, another SME is saying the solder resist cure level is suspect. I have had a industry SME make reference to this too. Adjusting the cure of the resist changes the surface energy
Electronics Forum | Thu Apr 09 21:15:43 EDT 2009 | qualityguy
Interesting, A north American Solder resist firm stated the same thing to a degree. They said altering the resist cure profile can effectively change the surface energy thus making the surface more conducive to conformal coat adhesion. At in coming
Electronics Forum | Thu Apr 09 06:22:27 EDT 2009 | qualityguy
We aware of the extend time for cure, and in the CA activity we tried plasma etch and expose the sample to the current process, a screen test of 4 cycles -50C to 125C and the CC held in place. Std IPC tape test passed in current process and modifie
Electronics Forum | Tue Apr 14 17:39:34 EDT 2009 | gregoryyork
Sorry been away for a while. It is actually due to high boiling solvents or plasticizers leaching from the porous resist that kills the cure as it puddles out and has nothing to adhere to. We do have some wipes to check the cure and are looking to ma
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