Actually the cracked vias I have witnessed in the inter barrell tend to start at
the intersection of the copper planes. A corner or stress riser starts the crack
during thermal shock tests. Don't understand how the extra non- connected pads
could help barrell, if so then there is no hope for a 2 sided board.
"Hinners Hans M Civ WRALC/LUGE" <[log in to unmask]> on 01/15/2002
07:40:50 AM
Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond to
"Hinners Hans M Civ WRALC/LUGE" <[log in to unmask]>
To: [log in to unmask]
cc: (bcc: Warren Crow/US/I-O INC)
Subject: Re: [TN] Remove unused "dead" pads on internal
layers
Hi Patrick,
As others have said, I don't think the class of board matters for "unused"
pads. It all depends on what your procurement documentation states, are you
building to drawing or is there a clause that says process improvements that
do not affect functionality are permissible.
"Are they really unused pads?"
They may be electrically nonfunctioning but they are there for a reason -
better lamination quality (avoiding low pressure areas or excessive prepreg
flow), better hole wall quality, better plating quality (esp. for any
isolated traces), reduced loading of your etch solution or better thermal
loading during assembly.
Hans
Integrity First - Service Before Self - Excellence in All We Do
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Hans M. Hinners
Electronics Engineer
Warner Robins - Air Logistics Center (WR-ALC/LUGE)
226 Cochran Street
Robins AFB GA 31098-1622
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-----Original Message-----
From: Patrick Lam [mailto:[log in to unmask]]
Sent: Friday, January 11, 2002 5:12 PM
To: [log in to unmask]
Subject: [TN] Remove unused "dead" pads on internal layers
Hi TechNetters,
For class 3 boards, is it acceptable to have unused pads removed on
interanal
layers.
Thanks,
Pat
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