Gary
Tell engineering that a conformal coating does not SEAL against
moisture. All coatings breathe allowing air, that may contain
moisture, to move in and out of the coating film; and water, given
enough time, will go through everything...
Also inform them that thicker is not always better.
Acrylic coatings (Type AR) that are qualified to MIL-I-46058C and
meet IPC-CC-830 will perform optimally at a coating thickness of
0.002 ± 0.001 mils. (50 Micron ± 25 Micron).
The application you describe is not dissimilar to aircraft seat
entertainment systems - many using AR coatings - and you really don;t
want to know what people do in their aircraft seat! How about
superloos? These are street toilets that are fully automatic....use
your own imagination....and they use AR coatings.
I should be interested to understand your engineers proposed test
protocol...
Kindest regards
Graham Naisbitt
[log in to unmask]
Phone: +44 (0)12 5252 1500
Mobile: +44 (0) 79 6858 2121
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On 20 Jun 2006, at 16:35, Bremer, Gary wrote:
> Engineering is recommending that we increase the thickness of the
> AR coating to .005 ± .002 to seal the boards against moisture.
> These boards are used on Boeing aircraft, my thought is to use UR
> coating due to the environment these boards are used.
>
>
>
> Is the Acrylic conformal coating the best choice for this application?
>
>
>
> Are there any problems with increasing the thickness of the Acrylic
> conformal coating?
>
>
>
> This box is open to the environment and with my knowledge of the
> mounting location the sanitary lines could be located above the
> electronics.
>
>
>
> Thanks
>
> Gary Bremer
> Senior Manufacturing Engineer, CIT
>
> Curtiss-Wright Controls Inc.
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