Hi, Werner, I'm a little puzzled. I believed the reason why so many folks drill 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. If the BGA's outer body temperature only is measured, isn't this going to be much hotter than the balls underneath, and especially those in the centre of the array? Which, then, is the best way to thermally profile a BGA, in your experience, or does it depend on BGA size versus T/C size? Peter Werner Engelmaier <[log in to unmask]> 12/11/2002 07:54 AM 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 Toby, Your question is a good one. What I have done--and it works--was to grind a depression in the ceramic component body deep enough for the T/C beat to fit flush into it. Than I epoxy the beat into this depression; the surface is still flush so not to affect the heat transfer. I also epoxy the length of T/C wires which ends with the T/C onto the the surface of the commponent; thus, the impact of the wires being heated faster than the component body and thus a giving me a higher t-reading at the T/C is minimized. This works for both IR and Convection reflow ovens. Werner Engelmaier Engelmaier Associates, L.C. Electronic Packaging, Interconnection and Reliability Consulting 7 Jasmine Run Ormond Beach, FL 32174 USA Phone: 904-437-8747, Fax: 904-437-8737 E-mail: [log in to unmask], Website: www.engelmaier.com --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------