Thanks Kenny,
The article underlines the 'dangerous' center placement, while, at the
same time, Richard's Doug Paul echoing more readily explains the
vibration impact vs. the secure point positions in the xy plane. I have
got enough inputs from you all to attack the problem. I'll ask the ANSYS
specialist here to make a FEM, or do a stroboscopic vibration test.
Many thanks, I know in what direction to go now. Like making a painting,
a white board is frustrating until you've put the first lines on. 

Inge

-----Ursprungligt meddelande-----
Från: TechNet [mailto:[log in to unmask]] För Bloomquist, Ken
Skickat: den 16 april 2007 19:19
Till: [log in to unmask]
Ämne: Re: [TN] SV: [TN] Placement of large flatpacks and BGAs close to
board edge

There's an interesting article that sort of talks to your question in
Fridays SMT.

http://urltea.com/5vu 

KennyB

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Hfjord
Sent: Monday, April 16, 2007 12:54 PM
To: [log in to unmask]
Subject: [TN] Placement of large flatpacks and BGAs close to board edge


Dear collegues,

I have heard of a thumb rule, never place them along and close to the
edge. Hence, we place them (when suitable) in the center. I have
forgotten why this rule. Was it because of vibration nodes, warpage
during soldering, tempcycle issues or what? Is there a IPC standard or
other reference?

Inge

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