Craig, I agree with Rex. As we were transitioning to lead free we went from fully leaded to tin/lead boards with BGAs that were lead free to lead free with a couple of tin/lead parts to fully lead free. For scenario two we used what we called internally our "hot lead" reflow profile - AFTER checking with all of our component manufacturers to make sure we weren't going to cook anything. Bev RIM -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Rex Waygood Sent: Thursday, May 01, 2008 10:01 AM To: [log in to unmask] Subject: Re: [TN] Pb-Free BGAs on a SnPb board We run a profile that is known to achieve a full melt of the lead free BGA balls (by section). The melting point of the ball is influenced by the lead in the molten solder so the temperature required to achieve a complete melt is lower than you might expect. On our boards the slight increase in temperature is regarded as safe for the remaining components. The boards have subsequently been through qualification without failure. Our customer was involved fully with the investigation and decision. There is an NPL paper which also demonstrates this produces a reliable BGA joint, under the conditions they checked :-). Rex Rex Waygood Technical Manager PartnerTech Poole Ltd Benson Road Poole Dorset BH17 0RY United Kingdom Tel: +44 (0)1202 674333 Fax: +44 (0)1202 678028 DDI: +44 (0)1202 338222 Mob: +44 (0)7887 997403 [log in to unmask] www.PartnerTech.co.uk -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Craig Sullivan Sent: 01 May 2008 14:30 To: [log in to unmask] Subject: [TN] Pb-Free BGAs on a SnPb board Good Morning, We are seeing an increased number of our customers that specify a Pb-Free BGA when the rest of the board assembly is SnPb. Of course when we reflow at the SnPb profiles, we don't always get a properly collapsed BGA. So we end up reworking the BGA. We don't run a Pb-Free profile because we don't want to risk damaging the SnPb components. I am sure we aren't the only ones that are experiencing this. So, I have a question or two: What is everyone else doing when a customer requires a Pb-Free BGA on a SnPb assembly? Many of the jobs I refer to are consignment, so it's not like we can order the SnPb part from the get go. What reliability issues do you see? Are there any extra steps that your company takes to ensure the Pb-Free BGAs collapse properly? Is there a "special" profile anyone uses for the best of both worlds? What are the advantages, if any, to use a Pb-Free BGA on a SnPb assembly? Thanks for any and all input. Craig Sullivan Manufacturing Engineer MPL Incorporated P: 607.266.0480 F: 607.266.0482 [log in to unmask] --------------------------------------------------- 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 ----------------------------------------------------- ------------------------------------------------------------------------ ------- The information contained within this e-mail and any attachments contained therein may be confidential and/or legally privileged and is for the use of the intended recipient only. 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