I see quite a significant practical difference in crack initiation for the roll direction vs. transverse. I'm sure specifications are available which support that. So the metal will withstand bends on either axis, but more severe bends for those with the axis of the bend at right angles to the roll direction. An additional element you need to be aware of is that you don't want any plated metal to get onto the flex in the vicinity of the bend: Doing so just about completely destroys the malleability of the conductors. Fortunately, most rigid/flex designs don't have plating added to the flex layers since its uncommon for vias to terminate there. Wayne Thayer >>> [log in to unmask] 6/1/2006 9:43 am >>> For rigid-flex boards fabricated, is it recommended that the copper conductors be aligned with the copper grain direction for bend-to-install applications? Would the copper foil grain direction have an impact on tear strength on bend-to-install applications. Any experience with this issue? Thanks --------------------------------------------------- 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 ----------------------------------------------------- Karen --------------------------------------------------- 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 -----------------------------------------------------