TECHNET Archives

April 2000

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Mark Holmes <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Tue, 11 Apr 2000 12:09:44 +0100
Content-Type:
text/plain
Parts/Attachments:
text/plain (60 lines)
Hello all,

Apologies if you get this message twice, I didn't get the usual the usual
'your message has been sent' message so I assume it has disappeared  into
the ether!

Anyway here goes:

I have a question for all you board manufacturers (and PCB designers) out
there. I have been working on an unusual 4-layer board which has 2oz copper
on all layers. The majority of the tracking is on the inner layers, and the
outer layers are effectively solid planes of copper. Many of the tracks on
the inner layers have to carry a lot of current, but there is also some
control circuitry which requires a clearance of 6.5mm from the high power
area. Here lies my problem. Due to the space limitations and clearance
required, I have tracked in a connector using 8th tracks which travel almost
the length of the board (around 110mm) along one edge. These 3 tracks are on
their own, 6.5 mm from the rest of the tracking, adjacent to each other with
8th gaps.

My question is - is this achievable? how much of a problem would this cause
the manufacture? The inner layers MUST be 2oz copper.

My second question is - If 2oz of copper was specified for all layers, is it
acceptable to plate up the inner layers from 1oz copper foil?
A manufacture told me they had done this (although in fact they had not!)
but I have never heard of this practice for inner layers before.

This is a hot issue for me a the moment and I would appreciate any advice or
comments.

Best Regards,

Mark Holmes

[log in to unmask]

Mark Holmes PCB Designer
Helvar Merca Ltd.
Hawley Mill, Hawley Road,
Dartford Kent. DA2 7SY
Tel: 01322 22 22 11
Fax: 01322 282 286
mailto:[log in to unmask]
http://www.helvar.com

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in
the body:
To subscribe:   SUBSCRIBE TECHNET <your full name>
To unsubscribe:   SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Keach Sasamori at [log in to unmask] or
847-509-9700 ext.5315
##############################################################

ATOM RSS1 RSS2