Steve, Thanks for the input to the standard. This was a very hotly contested issue with the last revision to the standard (610C). In synopsis, concern for PTH reliability was in regard to thermal shock conditions based upon some old documentation that I'm sure you are aware of, and input from companies that had experienced failures. The advancement of standards and allowances for PTH robustness may serve to cause new concerns and personally I've seen renewed issues concerning PTH reliability as a performance limitation. It would be useful to run some new tests using newer PWB technologies and see what the outcome and impact is today. I echo your concern for rework of PTH solder connections and even worse vias that have solder fill. Remember that the consideration to rework is a last resort and a drastic measure and certainly only one of the options available for consideration according to the IPC standards. We should not arbitrarily rework product without consideration for outcome based upon reliability and product performance. Other options are available under Disposition. Mel Parrish Director of Training Soldering Technology International 102 Tribble Drive Madison, AL 35758 256 705 5530 256 705 5538 Fax [log in to unmask] www.solderingtech.com -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Sauer, Steven T. Sent: Monday, May 13, 2002 7:33 AM To: [log in to unmask] Subject: Re: [TN] ReA610HoleFill Jim, Guy, Nancy and others, I respectfully submit the following: If the intent for the 50% hole fill allowance (in regard to PTHs with thermal or conductor planes) is to be limited to class 2 then the exception should be listed directly under "Acceptable - Class 2" not under "Defect - Class 3" on page 6-7 and table 6-2 should have a note that flags this allowance for Class 2. As we all know, it is impossible to clearly and concisely write with the English language in such a manner that all readers will properly understand the meaning or intent of the words that is or are being conveyed. Having not participated in the IPC-A-610 meetings (as Guy referred to), I and others do not have the luxury of understand the intent of certain requirements -- all that is affored to us is the written words. In this case, the intent may have been to limit the 50% hole fill requirement to class 2 but the printed words do not support this beyond the shadow of a doubt. I will prepare a Standard Improvement Form for IPC-A-610C and forward to IPC so the committee can fill more hours with antiquated prose about this subject. I on the other hand still believe that 50% hole fill on most class 3 products will not cause a problem in terms of long term reliability even under extreme conditions as apposed to reworking the solder connection. This statement is made under the premise that a well defined, developed and controlled process is utilized. If there is any objective evidence that 50% hole fill is a problem, I along with Sir Werner would like to review the data, hardware, photomicrographs, cross-sections, etc. Steve Sauer ---------------------------------------------------------------------------- ----- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------- ----- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------