OK, guys, here's one. Why is it so important for local fiducials to be placed near diagonal corners of BGA's. The keyword here is "SO". I've performed studies in the past detailing the natural tendency of BGA's to self-align during reflow. It's even lead to me to work on a patent concerning a BGA rework preform. What I'm wondering is....ssop's, tssops, qfp's, etc. have greater impact on placement quality when misplaced. And they do not self-align!!! I do, however, understand that BGA's balls are not easily seen once placed (you can only see the edges). But my point that I'm getting to is.....wouldn't you want local fiducials more at the parts that will not "self-correct" themselves during reflow than at the parts are more forgiving? Just wondering. Jason Gregory Software Specialist - NPI Group SCI Systems/Plant 2 13000 S. Memorial Pkwy. Huntsville, AL. 35803 (256) 882-4107 x3728 [log in to unmask] --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------