TECHNET Archives

January 2005

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:
Roger Stoops <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Roger Stoops <[log in to unmask]>
Date:
Thu, 6 Jan 2005 13:33:24 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (71 lines)
No Au, appears to be SnPb (have seen these failures on parts dated from 2001-2002).

Roger


-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Blomberg, Rainer
(FL51)
Sent: Thursday, January 06, 2005 1:24 PM
To: [log in to unmask]
Subject: Re: [TN] Solder Joint Failures after Short-term Vibration


Sounds like a brittle joint.  Are the leads pre-tinned to  remove excess
gold to avoid "gold embrittlement"?


> Rainer G. Blomberg
> Staff Production Engineer
> Space Systems - Clearwater
> Honeywell International, Inc.
> * Phone       (727) 539-5534
> * Fax         (727) 539-4469
> * Email       [log in to unmask]


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Roger Stoops
Sent: Thursday, January 06, 2005 1:19 PM
To: [log in to unmask]
Subject: [TN] Solder Joint Failures after Short-term Vibration

Hello all,

We are having an ongoing problem with solder joint failures on a 144-pin
PQFP processor, after short-term vibration. The board layout and mechanical
mounting apparatus were designed with vibration in mind, and have passed
vibration testing in the past. The same processor is used on a dozen other
assemblies, none of which have this problem.

The solder joints appear to exhibit dewetting, although there is a toe and
heel fillet.  The heel fillet is unusually large, and the top of the PQFP
lead has a grainy appearance instead of a matte or shiny appearance.  Some
leads can be pushed off the solder joint with very little pressure.
Sn62Pb36Ag2 solder is being used, and our EMS provider continues to claim
that boards meet IPC-A-610 class 2 requirements.

Any ideas as to what may be causing solder joint failures?

Also, any suggestions or recommendations (preferred) for a test house to
provide x-ray, microsection and composition analysis?

TIA & Best Regards,

Roger M. Stoops, CID+
Trimble Navigation Ltd., Dayton, OH, USA
Ph: +01 937.245.5288
Fax: +01 937.233.7511

Oh, and BTW, changing EMS providers is not an option...

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
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