TECHNET Archives

May 2009

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Kevin Glidden <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Kevin Glidden <[log in to unmask]>
Date:
Wed, 27 May 2009 07:54:18 -0400
Content-Type:
text/plain
Parts/Attachments:
text/plain (158 lines)
All great advice so far.  We use ImAg as our primary finish with little
issues.  We've covered most all of the bases, right down to specifying the
packaging requirements both to PCB suppliers and internally.  We perform
2-sided reflow and secondary hand soldering of wires, etc with no issues. We
do get occasional fingerprints in the finish from PCB handling, and that's
an on-going awareness issue.

Also, related to this, we have been considering use of the Cortec VPCI-125
plastic wrap: http://www.cortecvci.com/Publications/PDS/VpCI-125.pdf
It is a static dissipative film with anti-tarnishing properties, supposedly
good for ImAg as well.  IPC-4553 only mentions the silver saver paper
though.  Anyone yet using this wrap with good or bad results?  Offline
comments are OK.

Kevin


-----Original Message-----
From: Maurice Dore [mailto:[log in to unmask]] 
Sent: Wednesday, May 27, 2009 3:36 AM
To: [log in to unmask]
Subject: Re: [TN] Immersion Silver

Steve
Good place to start is IPC4553 - Silver tarnishes in the presence of sulfur
(Ag2S forms on the surface);

a. Storage & Handling
Handling-  Gloves worn by Operators at all stages of production 1. Immersion
silver boards should be packaged as soon as possible, to prevent exposure to
chlorides and sulfides in the air.
2. Use sulfur free, pH neutral paper to wrap stacks of parts and then
plastic wrap. Storage should be in sealed bags or sealed containers to
eliminate direct contact with air.
3. Wrapped packages should be stored below 30°C (86°F) and 75% R.H.
4. Do not use desiccant in the packages. Desiccant can contain sulfur
compounds.
5. Adhesive tape, adhesive labels, stamps, markers and rubber bands are
forbidden on silver boards and the sulfur free paper. They all contain
sulfur bearing compounds that will tarnish the silver coating.
6. If the original package is opened and not all of the boards consumed at
the EMS/OEM, they should be re-wrapped as soon as possible and returned to a
storage condition, preferably not-to-exceed 30°C (86°F) and 75% R.H.

b. Shelf Life
- Controlled Shelf Life in unopened Vendor packaging -  6 months and 4 weeks
resealed Vendor packaging
- Floor Life - Double Sided Reflow - 48 hrs max
- Floor Life - to complete all solder assembly (i.e. wave solder) - 7 Days
maximum Floor Life

c. Corrosion Prevention
-  Pads are non-soldermask defined, reduces risk of any creep corrosion ?
Pad to Pad Clearance reduces risk of electrochemical migration ? PCB
Supplier to observe ImmAg Thickness ( 0.2 - 0.4µm  )

The key is to reduce exposure time to sulfide and chlorides (remember to
check both site levels) - I noticed solderability issues after 14 days
exposure time that affects our wave soldering process. logistics of moving
between manufacturing sites should be ok if controlled as recommended.
 
Rgds
Moss




Steve Kelly <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
26/05/2009 22:00
Please respond to
TechNet E-Mail Forum <[log in to unmask]>; Please respond to Steve Kelly
<[log in to unmask]>


To
[log in to unmask]
cc

Subject
[TN] Immersion Silver






Good Afternoon,

Any concerns about using immersion silver as a finish. PWB has to take two
reflow cycles, 1 re-work cycle and one hand solder after the two reflows.
Parts have to be transported from one part of the country to another after
the two reflows. Thanks. Steve Kelly

 

Steve Kelly (PLEASE NOTE NEW E-MAIL ADDRESS)

(416) 750-8433 (work)

(416) 750-0016 (fax)

(416) 577-8433 (cell)

 


---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to 
[log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to 
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 
for additional information, or contact Keach Sasamori at [log in to unmask] or 
847-615-7100 ext.2815
-----------------------------------------------------


 
Connaught Electronics Limited
Company registration N°92489

 
This e-mail message is intended only for the use of the intended
recipient(s).
The information contained therein may be confidential or privileged, and its
disclosure or reproduction is strictly prohibited.
If you are not the intended recipient, please return it immediately to its
sender at the above address and destroy it. 
 
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16
for additional information, or contact Keach Sasamori at [log in to unmask] or
847-615-7100 ext.2815
-----------------------------------------------------

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------

ATOM RSS1 RSS2