Gottcha! Thanks Werner - and a good point to remember. I guess ramp rates will have to come down to accommodate the thermal inertia, without over-cooking other components - or we're going to have to come up with all kinds of masking or shielding ("sun shade") requirements and techniques. Thank goodness the lead-free zone hasn't expanded as far as Singapore yet (except for US customers). Peter Werner Engelmaier <[log in to unmask]> 12/11/2002 12:20 PM Sent by: TechNet <[log in to unmask]> Please respond to "TechNet E-Mail Forum."; Please respond to Engelmaier To: [log in to unmask] cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Aero/ST Group) Subject: Re: [TN] profiling BGAs Hi Peter, You are right, 'the reason why one drills up into the central ball of a BGA to place a T/C, is because it's these central contacts that generally suffer from insufficient heating owing to the shading effect of the overlying body of the component.' The question I answered was how to determine the temperature of a component body. This will be even more important given the idiotic drive towards lead-free solders, when solder reflow temperatures need to be higher and thus component temperatures as well. Thus, knowing the component temperatures will be even more important than now. Werner Engelmaier --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- [This e-mail is confidential and may also be privileged. If you are not the intended recipient, please delete it and notify us immediately; you should not copy or use it for any purpose, nor disclose its contents to any other person. Thank you.] --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------