Nancy, Check out the paper "A Comparison of Methods for Attaching TCs to PCBs for Thermal Profiling" which is on KIC's web page: http://www.kicthermal.com/press/articles.html along with several other good articles on reflow profiling. We were using Kapton, but recently found that it was masking the temperature by 5-10 C. The methods of attachment, in order of accuracy and repeatability that I've heard/read about are: temp-probes (or similar), hi-temp solder, aluminum tape, and Kapton/glue at the bottom. As for the questions: 1. where to put the thermocouple: board and/or paste as a minimum 2 typical or maximum profile: typical, but each assembly gets profiled. 3. specify typical condition: based on the solder paste suppliers recommendations and the board design (layers, thickness, size/mix components, etc). Well, that's my two cents, Al Kreplick Sr. Mfg. Eng. Teradyne, Inc. 978-370-1726 (Embedded image moved TechNet <[log in to unmask]> to file: 11/08/2001 03:25 PM pic08573.pcx) Please respond to "TechNet E-Mail Forum." <[log in to unmask]> To: [log in to unmask] cc: Subject: [TN] Reflow Process Profiling Methods Hi Technet, I need some help to identify the most common methods of thermocouple placement when profiling reflow processes. And while we are on the subject, I would also like to collect information on targeting for typical or recommended profiles versus absolute min/max boundaries. Just three easy multiple choice questions.... 1. Where do you put the thermocouple? a. Embedded in a solder joint? b. On top surface of a component? (If so - how do you attach the TC to the part?) c. On surface of the PWB? d. In air? 2. Do you target reflow profiles to fit a "typical" curve or do you just try to stay below a maximum? a. Target for typical? b. Stay below maximum? 3. How do you specify that Typical or Maximum condition? a. Peak Temperature and Maximum Time at that Peak? (Please define conditions.) b. Total time above a fixed value (usually 183°C or 200°C)? (Please define conditions.) c. Solder Paste Alloy composition for above values? (If you are running both SnPb and Pb-free, please reply for both) If any of you would like to share soft copies of actual time/temp profiles that you use for targeting or specifying an acceptable range of reflow, please email to me off-line. Thanks in advance for your help. Nancy Reynolds KEMET Electronics --------------------------------------------------------------------------------- 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 --------------------------------------------------------------------------------- --------------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------------