Vincent,
Attached is a screen shot of some gold plated copper switch
patterns.
The line width and space on the fingers is 20 thou.
For carbon ink deposited on copper, the copper finger width
is 32 thou
with 8 space thou between fingers. The carbon ink width is
16 thou with
a 24 thou space between the carbon fingers.
It's also possible to deposit carbon ink directly on FR4,
but I don't know
anything about the longevity of that configuration.
These numbers may be a few years out of date, so check with
your board
shop for recommended dimensions.
Regards,
Mike Finczak
CopperCAD Design
www.CopperCAD.com
905-488-8958
-----Original Message-----
From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of Vince Di Lello
Sent: May 13, 2005 2:49 PM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] Carbon Switch PCB Pattern Design Guides
Good afternoon once again fellow designers .. Things sure happen on
Friday's ... does anyone have any design guideline documents regarding
acceptable PCB patterns (specifically minimum trace & space) for carbon
or rubber switches? Please and thanks ...
Vincent Di Lello, CID+
Senior CAD Designer
Kaleidescape Canada, Inc.
vdilello@xxxxxxxxxxxxxxxx
(v) 519.772.6418
(f) 519.772.6401
(c) 519.835.4477
www.kaleidescape.com
Attachment:
switches.gif
Description: GIF image
