Good explanation Mary.... Just one footnote....
I used to make printed circuit boards... using a printing process... screen
printing, much like the way we put the component legend on our "silkscreen"
layer. We used fine stainless steel screen material stretched in an aluminum
screen frame and used a black ink that was applied using a squeegee onto the
bare copper surface through a lithographic photo mask that was embedded into
the screen. This left a fairly accurate image resist on the surface of the
board... when etched, it was removed with ammonia and water and a scrub
brush...
So ... Printing was used in the PCB or PWB manufacturing process... at least
back in 1975 when we were doing it... :)
Bill Brooks
PCB Design Engineer , C.I.D.
DATRON WORLD COMMUNICATIONS, INC
3030 Enterprise Court
Vista, CA 92083
Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510
mailto:[log in to unmask]
IPC Designers Council, San Diego Chapter
http://www.ipc.org/SanDiego/
http://home.fda.net/bbrooks/pca/pca.htm
-----Original Message-----
From: Mary L. Sugden, C.I.D. [mailto:[log in to unmask]]
Sent: Tuesday, October 30, 2001 11:41 AM
To: [log in to unmask]
Subject: Re: [DC] PCB or PWB: which is correct?
To: [log in to unmask] Attn: Gary Koven
From: Mary Sugden At: [log in to unmask]
Date: October 30, 2001 Subj: PCB/PWB?
Hello Gary,
In the beggining, there were Etched Circuit Boards. However, the need
for photo tools drove us to lithographers who worked in the printing
trade. Because of this early exposure to the printing trade, the
boards were soon called "printed" circuits, even though nothing about
them was printed.
After many years and many debates, someone decided that the term
circuit was inappropriate since the board only contained disconnected
conductors. The word "circuit" implies a complete path. As it is, a
board does not contain any complete circuits. So, they decided that
printed wiring board was a more correct description, even though
nothing was printed.
Some in the industry believed that both terms should be used. It
would be called a printed circuit if the electrical characteristics of
the board such as the distributed capacitance and inductance, were an
interactive part of the electrical performance such as in microwave
and controlled impedance boards. If the board did not interact with
or alter the electrical performance, it should be called printed
wiring. That is, the board was a passive interconnection structure
and had no effect on electrical performance.
According to IPC-T-50 Terms and Definitions;
Printed Circuit Board: Printed board that provides both
point-to-point connections and printed components in a
predetermined arrangement on a common base.
Printed Wiring Board: Printed board that provides
point-to-point connections but not printed components in a
predetermined arrangement on a common base.
No matter what the arguements, most of us still lovingly call them
printed circuit boards. As Grandma says, "It is better to ride the
horse in the direction it is going." I hope this helps.
Best Regards, Mary
Mary Sugden
The Copper Connection, Inc.
3003 Bunker Hill, Suite 201
Santa Clara, CA 95054-1106
Ph (408) 970-9838 Fx (408) 970-8184 [log in to unmask]
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