Not quite true. Any bake will drive out some moisture, but the combination of time and temperature and the surrounding relative humidity is what determines the amount of removal. But you also need to know that baking is going to have some negative impact on the solderability. You also need to know what effect it may have on the components, if they are present. Many components are not able to withstand a sustained bake process. Baking can also affect the flex performance, depending on what type it is. Not all flex is polyimide, and baking will negatively affect both PEN and polyester. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Kelly Sent: Tuesday, April 29, 2008 1:53 PM To: [log in to unmask] Subject: Re: [TN] Baking Flex boards Hi Bill, Most flex materials will withstand 125C continuous so you should have no issues. What is the point of this? If it is to drive out moisture before assembly all you are doing is warming the water. Regards Steve Kelly -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Bill Dworak Sent: April-29-08 2:46 PM To: [log in to unmask] Subject: [TN] Baking Flex boards I would appreciate some input on a subject that I was just hit with today. I am being asked if my customer baked flex boards for 10 hours at 150F would there be any chance of long term reliability issue? The board is what I would call standard issue stack up for a flex board nothing wild polyimide material with a FR4 Stiffener 4 layers, no fine traces .004/.004. HAL (leaded) surface finish. I had an issue several months ago with some rigid boards that where being baked for long periods of time but that was on the assembly side of issues not durability. Any particular issues that might come from the baking? Any input is welcome. Bill Dworak --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------