Depending on the type of adhesive process (thermal set or PSA tape) they could be applied at different stages. Typically they're done in panel form using external tooling holes for registration. If however, PSA tape is being used to apply then they could be applied in pc form and aligned by eye. As far as the size of clearance in the stiffeners normally they're slightly larger than the underlying pad that you plan on wicking solder to. If you're wanting a S/S flex without pads on the side your applying the stiffener to, then you could go smaller. It's best to contact the potential supplier and seeing what they recommend that will best fit their processes and get you what you need. Dan S. ----- Original Message ----- From: "Harris Dy" <[log in to unmask]> To: <[log in to unmask]> Sent: Friday, November 20, 2009 10:05 AM Subject: [TN] Stiffener on Flex Circuit Hi guys, I am not that familiar with Flex manufacturing so I would appreciate if you can share your knowledge and help me understand the process of adding FR4 stiffeners to Flex circuit. 1. At what point of the process is FR4 stiffener normally added to the Flex? 2. If there are holes that needs to be drilled on the stiffeners to match the Flex holes, is it drilled larger (due to misregistration?)? If so, by how much bigger? 3. I remember FR4 stiffeners were drilled and routed together with adhesive. How is it registered then to the Flex? It's not being attached individually or manually right? I would appreciate if you can explain in greater detail. Thanks for your help. HDY --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 15.0 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 -----------------------------------------------------