TECHNET Archives

October 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:
Joyce Koo <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Joyce Koo <[log in to unmask]>
Date:
Tue, 27 Oct 2009 14:44:36 -0400
Content-Type:
text/plain
Parts/Attachments:
text/plain (95 lines)
Last time I checked, none of the alloy pass the vib and fatigue test of the old Pb-Sn with Cd additive at low temp.  That was an 10 year old story. For the environmental friendly group, you would think fraction % of Cd with such safety benefit would out weight the cost.  But those guys never think alone the same wave length as me.  Give it up! 
--------------------------
Sent using BlackBerry


----- Original Message -----
From: TechNet <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Sent: Tue Oct 27 13:37:35 2009
Subject: Re: [TN] Reworking LF(SAC) Assemblies with SnPb Solder

Dave,

Echoing Denny's input, I would repair Lead Free (SAC) with Lead Free
(SAC) and Tin Lead (SnPb) with Tin Lead (SnPb). I would keep the two
technologies separated.

Just a warning, there are several papers out there that indicate that
you could do first piece production mixing technologies (SAC BGA / SnPb
paste or SnPb BGA / SAC paste), and some might imply that you can do
rework in the same manner. I am very skeptical on this since I work in
the aerospace arena and the test data documented does not come close to
what I have to deal with.

One more thing - your soldering temperatures with SAC are about 20C
higher than Tin Lead (SnPb). This means that you have to control your
processes better so you do not disturb the neighboring solder joints.

Hope this helps. Good Luck.

Lee Whiteman, PMP
Senior Member Engineering Staff
L-3 Communications East
Telephone: (856) 338-3508
FAX: (856) 338-2906
E-Mail: [log in to unmask]
 
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Dave Schaefer
Sent: Tuesday, October 27, 2009 11:53 AM
To: [log in to unmask]
Subject: [TN] Reworking LF(SAC) Assemblies with SnPb Solder

Working on a product that is exempt from RoHS requirements but does
require
LF(SAC) processing because of BGA ball solder composition. Most other
products are standard SnPb process, and rework is performed with SnPb
solder.

Am I correct to question the use of SnPb solder to rework the LF(SAC)
assemblies?

It would seem that mixing SnPB and SAC solder would result in an unknown
solder composition.

---------------------------------------------------
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
-----------------------------------------------------

---------------------------------------------------------------------
This transmission (including any attachments) may contain confidential information, privileged material (including material protected by the solicitor-client or other applicable privileges), or constitute non-public information. Any use of this information by anyone other than the intended recipient is prohibited. If you have received this transmission in error, please immediately reply to the sender and delete this information from your system. Use, dissemination, distribution, or reproduction of this transmission by unintended recipients is not authorized and may be unlawful.

---------------------------------------------------
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