Unfortunately, the clever CADder has put other components close to the corners. I think they will have  to move them. You are absolutely right. But I need a temporary solution, like Steve's maybe.
Thanks all for your contributions, sooner or later the coin will drop.
/Inge




From: Werner Engelmaier 
Sent: den 12 March 2010 13:19
To: [log in to unmask] ; [log in to unmask] 
Subject: Re: [TN] Vibration issue



hi Inge,
You must be hitting some Eigenfrequencies---by changing the vibrational characteristics you should be able to steer clear of the harmonics---I would think just staking the corners should do it.
Werner







-----Original Message-----
From: Inge <[log in to unmask]>
To: [log in to unmask]
Sent: Fri, Mar 12, 2010 1:47 pm
Subject: [TN] Vibration issue


Hi all, 
we are making a very vital part for a aircraft builder. Problem with TQFPs, some 200 legs. There are resonance peaks that kill the package legs. Redesign is not to think of from the customer, so we must do something on inside of the box. One solution (not popular) is to use a string of a glue along the leg rows in order to lock them. Another is to place a vibration dampening mat on one side of the board. That one is more tricky , but there is a US company with lots of stuff for that purpose. Anyone with experience from this area? I should add that not all legs are broken, just one or two after 100 hs of random vibration, but that is of course not acceptable. BGAs would solve the problem, but there is no time for redesign. 
I'm sorry for coming with a serious message at this holy time of the week. 
Thanks 
/Inge  
______________________________________________________________________ 
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
-----------------------------------------------------