Mime-Version: |
1.0 |
Content-Type: |
text/plain; charset="us-ascii" |
Old-Return-Path: |
|
Date: |
Tue, 6 Feb 1996 09:16:39 -0500 |
Precedence: |
list |
Resent-From: |
|
Cc: |
|
X-Status: |
|
Status: |
O |
X-Mailing-List: |
|
From [log in to unmask] Wed Feb 7 15: |
43:55 1996 |
X-Sender: |
gary@gateway |
TO: |
|
Return-Path: |
|
Resent-Sender: |
|
Resent-Message-ID: |
<"hLkju2.0.hZB.a2s5n"@ipc> |
Subject: |
|
From: |
|
X-Loop: |
|
Received: |
by ipc.org (Smail3.1.28.1 #2)
id m0tjo3T-0000CAC; Tue, 6 Feb 96 08:07 CST |
X-Mailer: |
Windows Eudora Light Version 1.5.2 |
Message-Id: |
|
Parts/Attachments: |
|
|
Much has been stated about non-functional lands, clearances in planes, etc.
Part of the problem, is that when one reads what is suggested in a design
standard, and it doesn't say what one wants it to hear, they look to others
for blessings.
The IPC-D-275, even with it's shortcomings suggests that a standard
fabrication allowance be accounted for in every land and hole placement
calculation. In the case of holes in plane areas, the standard fabrication
allowance must be added to the minimum electrical clearance requirement. It
also states that for inner layers, we are dealing with the drilled hole.
Last but not least, is that on a plane layer, clearance from the land,
should never be less than 0.010in.
The design standard recommendations are there to help the designer achieve a
manufacturable product. To ignore the recommendations, doesn't mean that the
problem goes away! Ignore them only if you have control of the processes.
|
|
|