Lee,
It Depends.

We have one facility that has never baked prior to coating application.  No
evidence of any conformal coating related problems.  We have several
facilities that bake religiously prior to coating application, also for
acrylic.  No evidence of any conformal coating related problems.

I think the biggest factor is how much residual water you have.  I don't
think your assemblies have to be bone dry before coating.  We do a lot with
in-line aqueous cleaners, which have heated air knifes that remove the bulk
of the water.  Now, there might still be some entrapment areas, but if so,
we find them and then blow out those entrapment areas with ionized air.


Doug Pauls
Principal Materials and Process Engineer
Rockwell Collins

On Tue, Feb 28, 2017 at 10:20 AM, Lee Hitchens <[log in to unmask]
> wrote:

> Hi all
>
> I've recently been asked about baking pcbs before conformal coating and
> whether there is any quantified data on the effect on coating performance.
>
> Does anyone know of any public studies on this or can shed some light on
> its effectiveness beyond anecdotal experience ? I would be very grateful to
> you on this.
>
> Best Regards
>
> Dr Lee Hitchens
>
> SCH Technologies is a Division of SCH Services Limited
>
> www.conformalcoating.co.uk
> Skype: leehitchens
>