Subject: | |
From: | |
Date: | Tue, 17 Oct 95 13:32:16 PST |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
YOUR SUCH A STAR.....
______________________________ Reply Separator _________________________________
Subject: Re: Non-Functional Pads?
Author: [log in to unmask] at internet_gateway
Date: 10/17/95 10:58 AM
Received: by ccmail from chopin.multek.com
>From [log in to unmask]
X-Envelope-From: [log in to unmask]
Received: from miso.wwa.com by chopin.multek.com with SMTP
(1.37.109.4/16.2) id AA27412; Tue, 17 Oct 95 12:00:59 -0700
Resent-Date: Tue, 17 Oct 95 10:58:28 PST
Received: from ipc by miso.wwa.com with uucp
(Smail3.1.28.1 #8) id m0t5HHm-000iOJC; Tue, 17 Oct 95 14:02 CDT
Received: by ipchq.com (Smail3.1.28.1 #2)
id m0t5GIj-0000HBC; Tue, 17 Oct 95 12:59 CDT
Old-Return-Path: <miso!multek.com!acochrane>
Date: Tue, 17 Oct 95 10:58:28 PST
From: "COCHRANE, ALAN" <[log in to unmask]>
Encoding: 79 Text
Message-Id: <[log in to unmask]>
To: [log in to unmask]
Subject: Re: Non-Functional Pads?
Resent-Message-Id: <"eBEyS1.0.n88.zx-Wm"@ipc>
Resent-From: [log in to unmask]
X-Mailing-List: <[log in to unmask]> archive/latest/1388
X-Loop: [log in to unmask]
Precedence: list
Resent-Sender: [log in to unmask]
Kevin,
I would think that if a vendor were to remove the non functional pads
then they would let the end user know. As you know I feel that non
functional pads are VERY benificial in the fabrication of boards.
1. More retained surface copper = improved or better controlled
dimensional stability
2.Complete pad stack to verify via x-ray, drill alignment
3.Complete pad stack to verify registration/misregistration via
x-section.
4.Copper to minimize the amount of drill splay specificly on thick
boards.
5. Additional copper to help remove epoxy build-up in the drill flutes
6. Extra interconnects to help deliniate the amount of z-axis
expansion and the stress on the interconnects.
The only possible negative that I see is on some high speed designs
where x-talk/coupling is a factor. If we remove the pads we can
increase the space from drill hole to trace.
I have heard alot of people say "why have more potential for shorts if
I don't need to." I would say to them "get a better AOI system"
Regards,
Alan B. Cochrane
Director of New Technology
Multek Inc.
______________________________ Reply Separator _________________________________
Subject: Non-Functional Pads?
Author: [log in to unmask] at internet_gateway
Date: 10/17/95 10:04 AM
Received: by ccmail from chopin.multek.com
>From [log in to unmask]
X-Envelope-From: [log in to unmask]
Received: from mx.smtp.psi.net by chopin.multek.com with SMTP
(1.37.109.4/16.2) id AA27280; Tue, 17 Oct 95 09:57:45 -0700
Received: from miso.wwa.com by mx.smtp.psi.net (8.6.12/SMI-4.1.3-PSI)
id MAA13812; Tue, 17 Oct 1995 12:49:28 -0400
Resent-Date: Tue, 17 Oct 1995 12:49:28 -0400
Received: from ipc by miso.wwa.com with uucp
(Smail3.1.28.1 #8) id m0t5FBj-000iKAC; Tue, 17 Oct 95 11:48 CDT
Received: by ipchq.com (Smail3.1.28.1 #2)
id m0t5Dn9-0000GlC; Tue, 17 Oct 95 10:18 CDT
Old-Return-Path: <miso!eag.unisysgsg.com!KTHORSON>
From: "Thorson, Kevin J @EAG" <[log in to unmask]>
To: "'IPC Technical Forum'" <[log in to unmask]>
Subject: Non-Functional Pads?
Date: Tue, 17 Oct 95 10:01:00 CST
Message-Id: <[log in to unmask]>
Encoding: 10 TEXT
X-Mailer: Microsoft Mail V3.0
Resent-Message-Id: <"k-ryW2.0.jt2.LbyWm"@ipc>
Resent-From: [log in to unmask]
X-Mailing-List: <[log in to unmask]> archive/latest/1384
X-Loop: [log in to unmask]
Precedence: list
Resent-Sender: [log in to unmask]
The design guides for MIL-STD-275 and IPC-D-275 require non-functional pads
on all layers of a multilayer PWB. Can manufacturers remove them an their
judgment?
If anyone knows the verse and script, that would be great.
Thank you in advance,
Kevin Thorson
Loral Defense Systems - Eagan
|
|
|