See IPC-2222 10.3
It says large areas may/shall/should be croshatched.  Three diff
paragraphs with three diff words.  Unless I misunderstand it even
INTERNAL areas should be broken up.  Anybody out there worrying about
that?
George W Uptain, Jr.
Austin Product Center of Schlumberger Oilfield Services
(512)331-3183


> -----Original Message-----
> From: Davis Ben [SMTP:[log in to unmask]]
> Sent: Friday, May 01, 1998 2:47 PM
> To:   [log in to unmask]
> Subject:      [DC] Solid vs. Hatch
>
> Greetings fellow designers...
>
> I'm having a bit of trouble explaining the reasoning behind using
> hatch
> fill vs. solid fill on outer layers.  I have, in the dark recesses of
> my
> brain, a memory of a rule of thumb saying to hatch any fill areas
> larger
> than 1 sq. inch.  I believe this was to prevent sucking too much heat
> during the soldering process, sucking too much solder during wave
> soldering (in uncoated use), and/or to prevent warping of the board.
>
> We currently have a board approx. 6x5 inches, predominately fill
> (chassis ground) on the secondary side.  We are using soldermask over
> bare copper on this 2-sided, .062, FR4 board..  The previous
> incarnation
> of this board was somewhat smaller and used solid fill with no
> problems.  Now I find myself trying to defend my choice of using hatch
> fill on the new board.  Perhaps my "rule of thumb" is no longer valid
> or
> was a myth originally.  It is easy convince others about the sucking
> up
> solder when uncoated issue, but since we have SMOBC they don't see
> this
> as a problem.  Are the warping and heat sinking issues valid?  Are
> there
> other issues/concerns I should address or use in my defense?  On the
> other hand, I don't mind if I'm wrong - solid/hatch is just a button
> push away!!!
>
> Thanks for any assistance you can provide.
>
> Ben Davis
> Systems & Electronics, Inc.
> [log in to unmask]
>
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