Received: |
by ipc.org (Smail3.1.28.1 #2)
id m0wFNZw-000BrtC; Thu, 10 Apr 97 12:24 CDT |
Encoding: |
70 Text, 30 Text |
From [log in to unmask] Fri Apr 11 11: |
25:52 1997 |
Date: |
Thu, 10 Apr 97 12:26:05 cst |
Precedence: |
list |
Resent-From: |
|
Resent-Sender: |
|
X-Status: |
|
Status: |
O |
X-Mailing-List: |
|
TO: |
|
Return-Path: |
<TechNet-request> |
Resent-Message-ID: |
<"77pIg2.0.NcP.e3IJp"@ipc> |
Subject: |
|
From: |
|
Old-Return-Path: |
|
X-Loop: |
|
Message-Id: |
|
Parts/Attachments: |
|
|
Well...I have seen post separation on boards with 0.0003"
etchback, so I think your PWB supplier is off base. Post
separation has many causes that cannot be solved with
providing a three sided lock (which is my guess as to why
they recommended etchback).
Your supplier has a post separation problem and will not
acknowledge it. They are being unresponsive. I know what I
do with suppliers like this.
If you want to call out etchback, remember it is more
expensive. There are plenty of suppliers out there who
desmear and have NO post separation.
Regards,
Dave Sullivan
Rockwell Collins, Inc.
[log in to unmask]
______________________________ Reply Separator _________________________________
Subject: Etchback
Author: [log in to unmask] at ccmgw1
Date: 4/8/97 7:44 PM
The purpose of this request is to solicited some opinions as to the
merits of etchback.
My company has recently had some field returns which analysis has
disclosed that the failures are a result of post separation. The PWB
supplier ,when contacted, suggested that if our drawing had required
etchback there would have been a less of a chance for a failure of this
nature to occur.
My company uses both IPC-RB-276 (IPC-6011&IPC-6012) and
MIL-STD-55110E as procurement specifications and it so happens we
have experienced failures in PWB's procured using both
specifications. The guidance furnished by either is not definitive
just if the Master Drawing say do it the etchback has to fall within
certain limits.
We have always gone with only a chemical desmear (permanganate) with
no apparent epoxy removal. We have never specified a chemical
etchback for fear of latent defects from residual chemicals. Our PWB
supplier tells us there is now available plasma etchback/chemical
desmear (permanganate) which we are told eliminates the potential
for the latent defect problem.
Does anyone have data which would provide information as to which
process would make the more reliable product. Any and all replies and
opinions welcome.
***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To subscribe/unsubscribe send a message <to: [log in to unmask]> *
* with <subject: subscribe/unsubscribe> and no text in the body. *
***************************************************************************
* 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 by ccmgw1.cacd.rockwell.com (SMTPLINK V2.11)
; Tue, 08 Apr 97 19:44:39 cst
Return-Path: <[log in to unmask]>
Received: from stealth.cacd.rockwell.com (stealth) by mailserv with ESMTP
(1.40.112.8/16.2) id AA054136184; Tue, 8 Apr 1997 19:36:24 -0500
Received: by stealth.cacd.rockwell.com; id TAA20555; Tue, 8 Apr 1997 19:34:09 -0500
Received: from unknown(168.113.24.64) by stealth.cacd.rockwell.com via smap (3.2)
id xma020551; Tue, 8 Apr 97 19:34:07 -0500
Received: from ipc.org by simon.ipc.org via SMTP (940816.SGI.8.6.9/940406.SGI)
id TAA16647; Tue, 8 Apr 1997 19:23:10 -0700
Resent-Date: Tue, 8 Apr 1997 19:23:10 -0700
Received: by ipc.org (Smail3.1.28.1 #2)
id m0wEjaQ-000BjkC; Tue, 8 Apr 97 17:41 CDT
Resent-Sender: [log in to unmask]
Old-Return-Path: <[log in to unmask]>
From: [log in to unmask] (BOB HAYNES)
To: [log in to unmask]
Subject: Etchback
Date: Tue, 08 Apr 97 17:15:20
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii
Content-Description: Message Body
Content-Transfer-Encoding: 7BIT
Message-Id: <[log in to unmask]>
Resent-Message-Id: <"JXOoc.0.99C.mciIp"@ipc>
Resent-From: [log in to unmask]
X-Mailing-List: <[log in to unmask]> archive/latest/11789
X-Loop: [log in to unmask]
Precedence: list
Resent-Sender: [log in to unmask]
***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To subscribe/unsubscribe send a message <to: [log in to unmask]> *
* with <subject: subscribe/unsubscribe> and no text in the body. *
***************************************************************************
* 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] *
***************************************************************************
|
|
|