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  Perhaps my "rule of thumb" is no longer valid or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]

################################################################
DesignerCouncil E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE DesignerCouncil <your full name>
To unsubscribe:   SIGNOFF DesignerCouncil 
################################################################
Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information.
For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311
################################################################