TECHNET Archives

March 2011

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:
Uppina Nagaraj <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, [log in to unmask]
Date:
Thu, 17 Mar 2011 08:39:55 +0530
Content-Type:
text/plain
Parts/Attachments:
text/plain (136 lines)
Hi George,

Surface finish is ENIG.

Regards,
U.Nagaraj


> U.Nagaraj
>
> What was the PCB surface finish?
>
> Regards,
> George
> George M. Wenger
> Senior Principal Reliability / FMA Engineer
> Andrew Corporation - Wireless Network Solutions
> 40 Technology Drive, Warren, NJ 07059
> (908) 546-4531 Office (732) 309-8964 Mobile
> E-mail: [log in to unmask]
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Uppina Nagaraj
> Sent: Wednesday, March 16, 2011 10:28 PM
> To: [log in to unmask]
> Subject: [TN] Query on failure of assembled PCB
>
> Dear All,
>
> 1. We are manufacturers of PCBs. One of our customer has reported
>    failure in assembled boards. The main observation is that after
>    assembly, the assembled units were functioning normally
>    and had passed all the stipulated electrical tests. These parts
>    were kept at the assembly house for around over 3-4 months. Later
>    when the assembled units were scheduled to be integrated into
>    the system, the assembled units were tested again, but now they
>    see failure.
>
>     These are the inputs given to us..........
>     a) Failures are intermittent in nature.
>     b) Failures are concentrated in and around the area where
>        BGA is mounted.
>     c) Some failures are recovered by applying mechanical stress on
>        the PCB.
>     d) Some are recovered by subjecting to reflow.
>     e) There are no component failures.
>
> 2. Our customer's assembly process flow is…
>     a) 100Deg C, 16 hours baking
>     b) Assembly done within 24 hours after baking
>     c) Pb-free reflow conducted with a peak temperature of 262Deg C
>     d) Reflow is done 2 times (once for each side of components)
>     e) Visual and physical inspection done
>     f) Cycling done at -20~+70Deg C for 10 cycles. First 9 cycles
>        are 30minutes per cycle and the last cycle is 1 hour cycle
>    g) Electrical testing
>
> 3. We had retrieved a blank PCB from the same batch and conducted
>    the following trial......
>
>    a) A standard step of baking prior to assembly (100Deg C,
>       16 hours baking) was skipped due to time constraint.
>    b) 2x reflow done at customer's place using standard profile
>       used for assembly of this part.
>
>      Electrical Testing (BBT) on bare PCB passed .
>
>    c) 10 cycles of temp. cycling done at customer's place using the
>       standard cycling profile used for assembled unit.
>
>       Electrical Testing (BBT) on bare PCB passed .
>
>    d) Repeated 2x reflow (2nd time) at customer's place using
>       standard profile used for assembly of this part.
>
>       Electrical Testing (BBT) on bare PCB passed .
>
>      Based on the above trial, we feel that the failure seen is
>      not due to PCB failure.
>
>
> 4. This particular PCB is a 8 layer PCB, built using ISOLA FR370HR
>    material.
> -----------------------------------------------------------------
>
>
> Please share your inputs and thoughts on the failure phenomenon and
> how to ascertain if the failure is due to PCB or assembly.
>
> Thanks in advance!
>
> Best Regards,
> U.Nagaraj
>
>
>
>
> ______________________________________________________________________
> 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.aspx?Pageid=E-mail-Forums 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.aspx?Pageid=E-mail-Forums for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------

ATOM RSS1 RSS2