Good morning Jack.  CC-830 is more of a materials document, not a process
document.  So it has nothing to do with keep out zones or overspray zones.
J-STD-001 does not really cover how to apply coating, only what the coating
must do.  There really is no document that answers the question that you
pose Jack.  One of the coating committees did create a white paper "What
coating people wish designers knew" last year.  It was published as an IPC
white paper, though I don't have the reference handy.  As I recall, we did
not really address the issues of keepout zones and what they should be.

The amount of overspray zone really depends on what technology you are
using to apply the coating.  Some technologies, like jet printing, can give
you a very defined perimeter around a keepout zone.  Different kinds of
spray have differing levels of how much overspray to expect.  So the answer
is "it depends".  It is best for you the designer to determine where the
presence of conformal coating interferes with the form fit or function of
the assembly.  Then we in manufacturing work to keep it out of that area.
From a manufacturer's perspective, I would say the answer is "as much as
you can give me".  You might go as far as to define "no coating here",
"coating optional in this zone (don't care)" and "coating here".  Allows us
some flexibility.

Oh, and staking compound means adhesive.  When we are gluing down big ass
components to the boards.


Doug Pauls
Principal Materials and Process Engineer
Rockwell Collins

On Wed, Dec 6, 2017 at 9:18 AM, Jack Olson <[log in to unmask]> wrote:

> I don't know what staking is, and I think they are trying to avoid
> masking/demasking.
> The goal is to spray everything except the mounting holes and a few exposed
> metal areas that we are using for thermal reasons.
> I was told I need to leave an "overspray zone" as neutral territory between
> those two types of areas
>
> On Wed, Dec 6, 2017 at 9:12 AM, Tan Geok Ang <[log in to unmask]> wrote:
>
> > Staking? Masking / De-masking?
> >
> > ------------------------------
> >
> > *From:* Jack Olson <[log in to unmask]>
> > *Date:* 6 December 2017 at 10:48:41 PM SGT
> > *To:* [log in to unmask] <[log in to unmask]>
> > *Subject:* [TN] IPC-CC-830 (Conformal Coat)
> >
> > What should a designer use as an "overspray zone" for conformal coating?
> > I would like to keep components and vias away from areas that will NOT be
> > coated.
> > I don't know why 3mm sticks in my mind, but I can't find anything in
> > IPC-CC-830 about it
> > (including the new Working Draft)
> > I also downloaded the new Conformal Coat ebook from 007 and can't find it
> > there, either!
> >
>