I vote to remove them all, thought the archives may have more
information.

We build boards to military 55110 and IPC class 3 here.  We prefer to
remove all of the non-functional pads on the internal layers.  If the
spacings are tight (under 6 mils for us), removing the internal nfp's
decreases the chance of shorts.  It can also helps the drilling
department out which can be a factor if you have thousands of small
diameter (less than .0135 drill bit for us) holes.

Steve Underwood
Engineering Manager
Circuit Center, Inc.
4738 Gateway Circle
Kettering, Ohio 45440
937-435-2131 ext. 127
937-435-7698 fax
[log in to unmask]




:-) -----Original Message-----
:-) From: TechNet [mailto:[log in to unmask]]On Behalf Of Hiteshew, Michael
:-) Sent: 09 January, 2001 11:49 AM
:-) To: [log in to unmask]
:-) Subject: [TN] Unused Inner Layer Pads: Remove or Not?
:-)
:-)
:-) Hi,
:-)         I have a pcb design with two fine pitch through
:-) hole connectors. In
:-) order to route between pins on inner layers I need to
:-) remove unused inner
:-) layer pads on that connector.
:-)         Here's my question: from a production point of
:-) view, is it better to
:-) selectively remove only those pads necessary or remove all
:-) unused inner
:-) layer pads (or is there no difference?). This pcb will be
:-) manufactured IAW
:-) IPC-2222 class 3. It's operating environment will be 0 - 70
:-) degrees C; no
:-) thermal shock anticipated.
:-)
:-)
:-) Michael Hiteshew
:-) Lockheed Martin NE&SS Marine Systems
:-) [log in to unmask]
:-) (410) 682-1259
:-)
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:-)

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