Subject: | |
From: | |
Date: | Fri, 3 Jan 1997 13:57:41 -0600 |
Content-Type: | multipart/mixed |
Parts/Attachments: |
|
|
An aspect ratio is the size of the hole to the board thickness or the
finished plated through hole to board thickness ratio. The aspect
ratio is an indicator for the degree of difficulty for plating the
hole. In the electroless process, the deposit of copper in the hole
is a chemical process and depends on the "throwing power" of the
electoplating equipment. The ability to deposit a complete and
continuous film of copper on the hole wall. As the aspect ratio
increases, the difficulty increases. IPC/DOD-D-275 lists the
following producibility levels for plated throug hole aspect ratio.
Preferred 1:5 or less
Standard 1:6 to 1:8
Reduced producibility 1:9 or >
If you have a thick board, (.093) and use a small hole .008, it is
hard to get uniform plating. The plating can go through the hole and
create a "dog bone" effect.
There is a cost adder when you go greater than a 1 to 8 ratio.
Char Dwyer
US Robotics
______________________________ Reply Separator _________________________________
Subject: Aspect Ratios
Author: [log in to unmask] (Isaac Stringer) at Internet
Date: 12/31/96 1:18 PM
Greetings:
Would someone be so kind as to explain 'aspect ratios' in a way
that will make sense to someone who understands hole sizes and
trace width/space?
Thank you!
Isaac Stringer
KML Engineering Corp.
[log in to unmask]
***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To unsubscribe from this list at any time, send a message to: *
* [log in to unmask] with <subject: unsubscribe> and no text. *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] *
***************************************************************************
Received: from usr.com (mailgate.usr.com) by robogate2.usr.com with SMTP
(IMA Internet Exchange 2.02 Enterprise) id 2C992720; Tue, 31 Dec 96 16:23:46
-0600
Received: from simon.ipc.org by usr.com (8.7.5/3.1.090690-US Robotics)
id QAA11525; Tue, 31 Dec 1996 16:25:20 -0600 (CST)
Received: from ipc.org by simon.ipc.org via SMTP (940816.SGI.8.6.9/940406.SGI)
id QAA15504; Tue, 31 Dec 1996 16:11:05 -0800
Resent-Date: Tue, 31 Dec 1996 16:11:05 -0800
Received: by ipc.org (Smail3.1.28.1 #2)
id m0vfBlC-0000UEC; Tue, 31 Dec 96 15:30 CST
Resent-Sender: [log in to unmask]
Old-Return-Path: <[log in to unmask]>
From: [log in to unmask] (Isaac Stringer)
Message-Id: <[log in to unmask]>
Subject: Aspect Ratios
To: [log in to unmask]
Date: Tue, 31 Dec 1996 13:18:37 -0800 (PST)
Cc: [log in to unmask] (Isaac Stringer)
X-Mailer: ELM [version 2.4 PL23]
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Resent-Message-ID: <"uN7Ry2.0.RDL.ENOoo"@ipc>
Resent-From: [log in to unmask]
X-Mailing-List: <[log in to unmask]> archive/latest/8890
X-Loop: [log in to unmask]
Precedence: list
Resent-Sender: [log in to unmask]
|
|
|