To bake or not to bake? Agh, that's the question, whether it's nobler in the mind's eye to bake and suffer the slings and arrows of solderability uncertainties or oxidental poisonings; or not to bake and go gently to that thermal excursion and watery grave of moisture ingression. The old dicy cured FR4s lulled too many people to idyllic complacencies. The times are changing and the newer engineered laminates demand proper attention to detail. Proper handling and storage conditions are mandatory. Baking protocols will need to consider some of the following: * Laminate type * Cure system * Tg of the laminate * Design robustness * PB layer count and thickness * Final surface finish * Processing window * Processing profile(including ramp rate, max. temp., and TAL) * Compensating factors Laminates that are destined for High-rel, Lead-free applications will probably require baking. To paraphrase; If in doubt Bake it out If not Lose the lot Dewey -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Joel Alexander Sent: Tuesday, October 23, 2007 9:23 AM To: [log in to unmask] Subject: [TN] Delamination of lead free PCBs Has anyone experienced an increase of delamination when processing in a lead free environment. Typically 4 to 6 layer pcbs during SMT reflow. We are using the high temp laminate suggested for our process. When we contacted the supplier and they indicated that any PCBs that are over six months old should be baked prior to processing. This was never required with leaded PCBs. Is anyone seeing the same condition and similar feedback from your PCB suppliers Joel Alexander Quality Assurance Manager TT APSCO, INC. --------------------------------------------------- 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 -----------------------------------------------------