Dennis I will not be attending Apex, but would like to take part in the committee. You asked for inputs here they are: I would comment that spread does not give an indicator of joint strength as such, which is indeed a function of solderability and more importantly maps directly to reliability. When you get right down to it the function of a solder joint used to be two-fold, now of course there are 3 which are: 1 Form an interconnect of acceptably low resistance which will not degrade under the expected working conditions/life of the product. 2 Form a reliable mechanical anchor for the component being connected through all stages of manufacture and all expected field conditions for the life of the product. 3 Comply with all recycling and toxicity regulations operating in the target market. Obviously 3 should be a given, but I believe there is a major element of 2 that cannot be satisfactorily measured by a standard spread test. Perhaps a standard spread test will give a general indicator of "solderability" but is going to be much impacted by the flux systems in the paste chosen. I believe a very useful addition to any such standard would be to generate as part of the test coupon a ball attach area and then measure the shear force at a committee determined shear speed. This I believe would nail once and for all the horror stories (which are real and have cost millions of dollars even in one example) of boards delivered, manufactured and shipped with various metallurgy issues such as those experienced with the ENIG process, which (apparently) pass the "solderability tests" currently in place. The metallurgy of the ball could map usefully to the expected joint composition and be selected from a list. Just my thoughts, Kind regards, John Burke John Burke Senior Manager - Operations , Optichron [log in to unmask] W: 510 249 5233 M: 408 515 4992 http://www.optichron.com Profile: https://www.linkedin.com/e/fps/2665502/ -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Dennis Fritz Sent: Tuesday, February 07, 2006 7:19 AM To: [log in to unmask] Subject: [TN] Solder paste spread as a measure of solderablity Hello - We will be starting a new focus topic at the Thursday meeting of 5-23d Committee - Alternate Final Board Finishes Task Group. That meets at 3:15 on Thursday in Room 208A at Expo/Apex. We are looking to develop standard testing to measure solderablity of all board finishes, particularly after stress - storage, heat, humidity, etc. Our task group inputs to the J-003 Board Solderablity Standards Committee. Issues may come up including: A standard dot method for all finishes would be desireable, if possible. Is there a "standard solder paste"? that can be used Slump versus spread + hot slump method Possibly create an "index" for paste spread Evaluation of paste/finish combination Collect information on spread - possible round table in future. If you cannot attend, all comments on the possible test methodology would be appreciated. Dennis Fritz, MacDermid Committee Chairman - 5-23d Alt Finishes --------------------------------------------------- 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 -----------------------------------------------------