Hi Dale - Do you have any pictures that you can share with the group? A visual would assist in providing you accurate information. Dave Hillman Rockwell Collins [log in to unmask] "Hart, Dale L CTR USAF AFMC AFRL/RXSA" <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 07/20/2010 08:23 AM Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to "Hart, Dale L CTR USAF AFMC AFRL/RXSA" <[log in to unmask]> To [log in to unmask] cc Subject [TN] solder joint height We have been doing a some analysis of cca's for the Air Force consisting of SMT. The visual inspection of the solder joints looks very good all characteristics above the suggest minimum for class 3 of 610. The solder fillets in some instances could be characterized as being robust. In cross-sectional analysis however, the solder joint height of the components electrical termination above the land has been perhaps 0.025 mm to the point of needing a SEM to look at the land-solder-component lead interface. Closer examination in these areas revealed small cracks in the grain boundaries. I used the term grain boundaries because the solder in these areas do not resemble the colonies observed in the bulk solder of the fillet. In some of these instances the land is often deformed in the shape of the component lead. Would these joints although stronger be more susceptible to fatigue or overload failure? What are the implications if these cca's are encapsulated? What suggestions could be offered to the manufacturer? Dale L. Hart Universal Technology Corporation (UTC) Failure Analysis 1270 North Fairfield Road Dayton, Ohio 45432-2600 (937) 656-9165 Fax (937) 656-4600 Email: <mailto:[log in to unmask]> [log in to unmask] --------------------------------------------------- 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 ----------------------------------------------------- ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- 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 -----------------------------------------------------