Gregg, Destructive tests, whether useful or not, are slow and expensive. I have tried various ways to evaluate solder joints, but the number of variants of lead size, lead type, pad properties, grain size, solder compositions etc was so abundant, that the idea of quality checking by means of solder destructive tests was abandoned. Instead, we hope that advanced 3-D X-ray analysis methods will be developed for incoming tests or final inspection. Some authors mean, that these methods will provide more data in less time than do traditional cross sectionings and shear tests. 3-D X-ray is fast and non destructive and will pay back in the long run. First, one needs collect a large number of X-ray laminographic slice images from the chip or gull wing solder joints. These images are then used for meshing in 3-D modeling and producing high speed reconstructional algorithms. One can draw a parallel with our new 3-D automatic, contactless inspection machine. In a few seconds, this machine performs dimensional measurements on hundreds of balls on a BGA, and presents the results in a number of ways, histograms, tarts, tables, curves etc. The coplanarity of component is measured in seconds. Same way, many hope that the 3-D X-ray laminography will be useful for evaluation of solder joints. In the end, you may have a register of references for gullwings, SOTs, BGAs and so on, which makes it possible to check a large number of solder joints in reasonable time. One may make a comparison with the hundred-year old method of solder joint inspection: visual inspection. Experienced eyes can get a surprising lot of information out of just looking in a microscope. Strong and reliable solder joints pass, and suspect or weak or unreliable joints are rejected. The 3-D X-ray laminography would compensate for what the human eye can't see. Like CATscan of a human body. Maybe, students could work with the development of the mentioned method? I have not followed what happens here. I saw the first articles 10 years ago. A lot must have passed since then. Is the method used daily somewhere? Is the machine affordable? Inge -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Gregg A. Owens Sent: den 16 mars 2007 19:05 To: [log in to unmask] Subject: [TN] SMT Solder Joint Strength Dear Technetters: Again I have a student asking a good question for which I don't have a reply. What IPC standard(s) or test method or methodology does one apply to test or evaluate the strength of a SMT solder joint adherence to the land (such as a chip or gull wing). Thanks, Gregg Owens, MIT MTTC, Inc. Mira Loma, CA 91752 --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------