Hello Again Werner: I sincerely appreciate your consideration of my proposal that coupons specific to LF performance be considered as part of the PWB and PWA quality lexicon. I apologize for the length of my response but I am very interested in your continuing views on this subject. To that end I offer the following: Specific to what would benefit coupons would offer, the clear directive would be to have a clearly defined test methodology stating unequivocally that the laminate will withstand the LF processes of the respective assembler. For this particular point, the obligation for LF compliance must first rest with the laminate manufacturer. The spec sheets must be true in their statements that the Tg and Td call outs are exactly as advertised and that coupons from the particular lot be provided to the fabricator at time of purchase. Secondly, the fabricator must thusly provide coupons (if requested) for customer review (much like the old mil-p-55110 as I recall) that would show the boards have been laminated/processed correctly and will in fact withstand the subsequent demands of LF soldering. This takes into account the different types of laminate a customer may require for its end product whether it is 2layer, multi-layer, flex or flex-rigid. Lastly, and finally, the CM/OEM must also test their own specific process using coupons provided from the same lot the fabricator used to ensure the re-flow process is in line with the laminate's stated capabilities as mentioned earlier. There are two wild-cards at the assembly level...the type of components utilized and the temperature required to re-flow them, and, the method of re-flow (hot-air/IR/solder-reflow) utilized. However, that is why the assembly resources would be well served to test these coupons prior to assembly to ensure their particular process will not be outside the parameters of that the designers designed in. Therefore, It is my considered view that now more than ever a co-operative engineering strategy be employed that includes fabricators and assemblers when determining laminate choice within product design. This of course is the "HARD WAY" which takes more time and probably some additional cost however the pay-off will be substantial in quality product, reduced defects and a happy customer. In comparison, no one thought before today that oil recovered from oil sands/shale could be done economically unless the price per barrel was at $60/bbl. That is where oil is today; $60/bbl! and the USA has (as I have read) over 150 years of oil sands reserves which is now being considered for our future needs. In comparison, With the advent of RoHAS and LF, it may finally be economical for the electronic designer and supplier to finally come together for co-operative engineering as it has now become cost effective to behave in this way. 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 Werner Engelmaier Sent: Tuesday, December 13, 2005 10:00 AM To: [log in to unmask] Subject: Re: [TN] Qualification of the Pb-free capable manufacturers Hi Charlie, Yes, that would serve. We have "PTH/PTV Reliability Coupons," "Registration Coupons" and "SIR Coupons"--why not "Delamination Coupons." At this point, it is however not clear, at least to me, which PWB design features [lots of Cu, little Cu, coupon size, etc.] are the most critical in terms of lamination. But my question is as 'Why should the burden not be on the suppliers?'--they control the properties of their materials and it should be part of their data sheets. Unfortunately, data sheets are made of very uncomplaining paper--I have found data sheets from large 'reputable' suppliers giving CTE values of FR-4 material as low as 11 ppm/C when the true CTE when we measured it was almost double. Why is it, that in our industry, most of the suppliers are part of the problem rher than part of the solution? With this 'Lead-Free' insanity and the lack of resources, we had better all contribute or face the consequences. 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 ----------------------------------------------------- -- 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 -----------------------------------------------------