Reply to: RE>Nickel/Gold Immersion
Harlan:
Not knowing the requirements for your assembly, I can only suggest an
alternative that works well for mixed technology assembly and that is also less
expensive and more "solder pot friendly". If you use an OSP copper coating
(e.g. ENTECH-106) instead of Ni/Au, the flux from the wave solder will dissolve
the coating on teh secondary side during pre-heat, the solder will wet to the
clean copper underneath and the flux/OSP will be washed off in the post-wave
cleaning operation. Thus, the solder pot will not get contaminated as fast as
with Ni/Au.
Entech is reputed to survive 6 thermal cycles without degradation, which means
you could perform (1) SMD assembly/reflow, (2) secondary adhesive
dispensing/assembly/thermal cure, (3) wave solder, and several rework cycles on
the primary side of the board without degrading unassembled unsoldered sites.
Bill Fabry
Truevision, Inc.
--------------------------------------
Date: 3/29/96 6:03 AM
To: Bill Fabry
From: Vince, Harlan
We have experienced dramatic yield improvements in SMT by
utilizing Nickel/Gold (2-6 micro-inches of Gold over 100
micro-inches of Nickel) instead of Tin/Lead(HASL) on our Printed
Wiring Boards. Due to Mixed Technology Designs, several of these
Designs are processed through Wave-Solder. We have experienced
the obvious, increased Gold contamination in the pot, but yields
have also increased. We have stepped-up Pot samples and Pot
changes to overcome this problem.
Is anyone else processing Nickel/Gold plated Printed Wiring
Boards across Wave-Solder and have there been any problems other
then what I have listed above?
Thanks for your time - Harlan
------------------ RFC822 Header Follows ------------------
Received: by rainbow.rasterops.com with SMTP;29 Mar 1996 06:03:10 -0800
Received: from ipc.org by simon.ipc.org via SMTP (940816.SGI.8.6.9/940406.SGI)
id HAA25079; Fri, 29 Mar 1996 07:55:29 -0800
Resent-Date: Fri, 29 Mar 1996 07:55:29 -0800
Received: by ipc.org (Smail3.1.28.1 #2)
id m0u2duA-000079C; Fri, 29 Mar 96 07:07 CST
Resent-Sender: [log in to unmask]
Old-Return-Path: <[log in to unmask]>
Date: Fri, 29 Mar 96 08:10:09 EST
From: "Vince, Harlan" <[log in to unmask]>
Message-Id: <[log in to unmask]>
To: [log in to unmask]
Subject: Nickel/Gold Immersion
Resent-Message-ID: <"qRjnf1.0.X23.X2-Mn"@ipc>
Resent-From: [log in to unmask]
X-Mailing-List: <[log in to unmask]> archive/latest/3193
X-Loop: [log in to unmask]
Precedence: list
Resent-Sender: [log in to unmask]
|
