Larry,

A major reason for hatched versus solid is solid boards tend to warp during
wave solder.  If the issue is ground plane, the hatched works as well as
solid (yes, frequency of operation may make this statement false).
Generally ground plane is there for shielding purposes and if you remember
what a faraday cage is like you can use either solid or hatched.  Much of
our product uses high currents (tens of amps) on our converter boards and we
tend to use large areas of solid copper for current carrying as well as heat
sinking.

A down side to large solid areas of copper is the thermal drain made on
solder joints in the solid area.  The absence of thermal reliefs at each
hole made both hand and wave solder difficult to achieve desirable results.

The moral of this story is that large areas of copper should be hatched and
have thermal reliefs at plated through holes for optimum soldering.

Just one man's opinion.

Regards,

Phil Nutting
Manufacturing Engineer
Kaiser Systems, Inc.


-----Original Message-----
From: Larry Jindra [mailto:[log in to unmask]]
Sent: Monday, October 23, 2000 9:46 PM
To: [log in to unmask]
Subject: [TN] Crosshatch vs Solid Fill


We are having some discussion of the pros/cons of crosshatch vs. solid fill
for copper ground planes on surface layers of multilayer boards.  Perhaps
someone can help me with some answers.

Is there a discernable difference in soldermask adhesion?
Does the extra copper detract from reflow or rework operations?
Is there a difference in board warp susceptibility?
Why would an electrical guy want one vs. the other?


> Larry Jindra
> TRW/Avionics Systems Division
> mailto:[log in to unmask]   ph (858) 592-3424   fax (858) 592-3606
>

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