Hello Werner: Your guidance is always prescient and timely. The suppliers you refer to I assume are laminate suppliers and I am curious as to their lack of support of your STII proposal. As you clearly stated, the "instruction manuals" (my words) that come with the laminates as purchased by fabrication suppliers will have little use in terms of application questions for the end user based on the lead free demands of processing. Therefore, would it not be appropriate that, absent your STII proposal, the clients we supply with PWB first process coupons for each board design at assembly to ensure delamination does not occur BEFORE production. It appears that without an empirical benchmark as you properly suggest with the index, there is no other measurement of performance except the lawsuit to come when the assembled boards breakdown after assembly. I predict a blame the fabricator and assembler future for us all. I recall this being an issue when double sided SMT assembly came in requiring multiple reflow temp. exposures to the PWA. Process soon followed. Shall there not be a procedure/process in place to do manually (read: coupons) what the STII would do otherwise? At the very least it would indicate parameters. As one who believes in the Deming co-operative engineering principles and strong DFM at the fabricator, this strikes me as the one insurance policy that we need to consider. What is your view? Charlie McMahon McMahon Sales Company P.O. Box 1024 Windham, New Hampshire 03087 Tel: 603-432-3111 Fax: 603-432-6854 Cell: 603-401-4646 e-mail: [log in to unmask] -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard Sent: Tuesday, December 13, 2005 8:57 AM To: [log in to unmask] Subject: Re: [TN] Qualification of the Pb-free capable manufacturers Werner, You are absolutely correct, as usual. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier Sent: Monday, December 12, 2005 6:16 PM To: [log in to unmask] Subject: Re: [TN] Qualification of the Pb-free capable manufacturers Hi Paul, I certainly concur with you technical assessments--the reliability bottleneck for LF-soldering will be in the PWB as well as in the component areas, and less though with the solder joints, where most of the efforts are concentrated. There are people that understand these issues--there is you and PWB Solutions, there is Hans Danielsson in Europe and I give workshops on these issues. But you are correct, that the industry has not yet grasped the importance of these issues. Thermal excursions to SnPb soldering processes cost between 12 and 14% of the life of the PTHs/vias--going to LF-solders and a 30C increase raises the cost to 18 to 20% of the life--no wonder you saw what you reported. The slash sheets for laminate/prepreg materials given in IPC-4101 are so wide open in the ranges of properties that they are in fact useless. New slash sheets IPC-4101B/99, /101, /121, and /124 have been proposed for use for LF-soldering--again, the property ranges are much too wide to be useful for any designer. I proposed a "Soldering Tempreature Impact Index [STII]" for these slash sheets and was promplty shot down by the committee consisting of lots of suppliers. The STII incorporates the 3 most important properties in this context, Tg, Td, and CTE. Yes, there are people out there that understand the issues, the rest of the industry will have to learn the hard way. Regards, Werner Engelmaier Engelmaier Associates, L.C. Electronic Packaging, Interconnection and Reliability Consulting 7 Jasmine Run Ormond Beach, FL 32174 USA Phone: 386-437-8747, Fax: 386-437-8737, Cell: 386-316-5904 E-mail: [log in to unmask], Website: www.engelmaier.com --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 ----------------------------------------------------- -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.371 / Virus Database: 267.13.13/199 - Release Date: 12/13/2005 --------------------------------------------------- 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 -----------------------------------------------------