Graham,
MY opinion only.

Definitely not option three.  Either one or two, but it seems that you have a bigger problem than just manufacturing. It sounds like this part is not a good choice to be naked out in the use environment. So, I would pick  option #2 and then conformal coat the board.

Regards,
Bev

Sent from Mail for Windows 10

From: Graham Collins
Sent: Friday, December 1, 2017 12:08 PM
To: [log in to unmask]
Subject: [TN] board wash / non-washable modules - the dilemma

Hello Technet!

Wondering what other people are doing with this dilemma.

We have had several customers design in pre-built RF modules on their boards.  I totally get why, it is a pre-built, FCC approved, easy solution - the fastest way to get a good Wi-Fi or bluetooth solution.

Where things go off the rails for me are where this is used in a high humidity application (e.g. a marine setting).  We strongly prefer to wash boards, we can build no-clean if needed but I'd prefer not to for an on the water use.  But the part a customer has designed in specifically says not to wash it (it has an EMI shield, so they are properly concerned with water entrapment).

So - would you:

 - build it no-clean?
 - leave the part off, build and wash as usual, install RF module later using no-clean?
 - wash it (and maybe bake it to dry it out)?
 - ????

--
regards,

Graham Collins
Senior Process Engineer
Sunsel Systems
(902) 444-7867