I also use a polyimide kapton tape. A good technique for attaching a TC is to place it on a foil on the pwb and put the tape over the business end (the weld) and then use SMT chipbonder about 1/2" behind the tape to hold the TC firmly in place. The first time through the oven the epoxy will lock up and hold the thermocouples. The Kapton tape directly over the weld will reduce the reading by exactly 1 deg. C; it is almost transparent to the heat. Press the tape firmly around the weld to hold the weld in contact with the foil so you get a nice solid line in the graph. If it is not in contact it will measure the air temperature rather than the foil temperature, and the line in the graph will be quite jumpy and erratic. Be sure to put all of the TCs your profiler can load onto the pwb in a widely distributed manner when profiling a new pwb, and see which process provides you with an acceptable process window. Usually putting the board on the chain conveyor gives you the most delta T (the smallest process window) between the edges of the pwb and the center (sometimes up to a 20 deg C difference), but this may be OK for smaller .062" pwbs, the second worst process window is provided by placing the pwb directly on the mesh or link conveyor, which robs a small amount of heat from the bottom side, but is evenly distributed. This only works for single-sided pwbs, of course. The widest process window is to put the pwb in a pallet or carrier fixture that suspends the pwb with long narrow fingers holding the pwb. This robs the least amount of heat, and provides the best dispersion of heat over the entire pwb. A good delta T to shoot for is a variation of no more than 5 deg. C deviation from the mean over the entire pwb. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Jeffrey Bush Sent: Tuesday, March 21, 2006 9:18 AM To: [log in to unmask] Subject: Re: [TN] thermocouple attachment We use a Polyimide Kapton tape. Jeffrey Bush Director, Quality Assurance and Technical Support VERMONT CIRCUITS INCORPORATED 76 Technology Drive - POB 1890 Brattleboro, Vermont 05302 Voice - 802.257.4571 ext 21 Fax - 802.257.0011 <http://www.vtcircuits.com/> -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Dominic Boudreau Sent: Tuesday, March 21, 2006 9:56 AM To: [log in to unmask] Subject: [TN] thermocouple attachment Hello Techneter's, I am searching for a non-destructive technique for attaching thermocouples to a PCB for thermal profiling. I already know the technique with Aluminum tape proposed by the study made by KIC but I wanted a technique with some components installed on the PCB. Thank you Dominic --------------------------------------------------- Technet Mail List provided as a 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/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 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/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 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------