Hi Technetters: Thermal stress test per IPC 6013 calls out for 3 different temperatures (288C, 260C, 232C) at which the test could be performed to determine whether the flex circuit will withstand assembly and repair heat excursions. The procedure is meant to encompass a wide variety to flex circuits - from double sided to complex rigid-flex and made with a wide variety of materials - from polyester to polyimide. The question I have is regarding the rigid section of a typical rigid-flex contruction. This section can be built up with all polyimide materials and prepreg, typical FR-4 epoxy and adhesiveless material, epoxy adhesive instead of prepreg or acrlyic adhesives instead of prepregs. How would one go about determining the correct temperature to use when performing thermal stress test if the construction is typical FR-4 (Tg 140C) and acrylic adhesive for bonding as well as coverlay, so that the test truely represents the reliability of the construction and not induce failure due to higher temperature excursion which the construction may not withstand? The part has to go through a typical rigid-flex reflow process in the assembly twice. Thanks for your help in advance. Chetan Shah ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################