We have found ENIG and HASL to have 1 year+ shelf life without any special care being taken
for boards of various sizes (from 2" x2" up to 4" x 6").
Bob Landman
H&L Instruments, LLC
----- Original Message -----
From: Inge
[mailto:[log in to unmask]]
To: [log in to unmask]
Sent: Fri,
16 Apr 2010 13:33:32 -0400
Subject: Re: [TN] PCB Shelf life
> We have found a factor that is not to be found in any standard or
> paper,
> namely, the size of the components. If you have e.g. a mobile
> telephone
> card, all components are the tiniest that are to be found on the
> market.
> With that follow extremly small solder pads equal to extremly
> small solder
> volumes. Such card are more sensitive to solder tarnish than
> board with
> much bigger components. Therefore, Ericsson have a storage
> maximum of a
> couple of weeks only. I have never seen a investigation of that
> condition.
> Nor any calculations or rules.
>
> Inge
>
> --------------------------------------------------
> From: "Bill Belanger" <[log in to unmask]>
> Sent: den 16 April 2010 10:14
> To: <[log in to unmask]>
> Subject: Re: [TN] PCB Shelf life
>
> > Hello Angel,
> >
> > As a former PCB fabricator, I'm not sure that the base material
> has a
> > shelf
> > life. It's usually quite stable, and lasts a very long time in
> the field.
> >
> > Solderability, however, is a different story. Some surface
> finishes can
> > preserve solderability for many years, such as HASL (Hot Air
> Solder
> > Level),
> > which essentially coats any exposed copper with solder. Others,
> such as
> > immersion tin and OSP (Organic Solderability Preservative),
> measure their
> > shelf life in months, weeks or days.
> >
> > Hope this helps,
> >
> > Bill Belanger
> >
> > ---------------------------------------------------
> > 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
> > -----------------------------------------------------
>
>
> ______________________________________________________________________
> This email has been scanned by the MessageLabs Email Security
> System.
> For more information please contact helpdesk at x2960 or
> [log in to unmask]
> ______________________________________________________________________
>
> ---------------------------------------------------
> 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
> -----------------------------------------------------
>
>
______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
---------------------------------------------------
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
-----------------------------------------------------
|
