I should have exclude voiding at the interface, as they are a different story all together and I want to read the paper Dave referred to, as it's rather difficult for me to understand why Pb-free solders "wouldn't follow" the fracture mechanics rules. Regards, Vladimir -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D. Sent: Sunday, February 24, 2008 7:12 PM To: [log in to unmask] Subject: Re: [TN] Shrink hole voids That is no longer held to be true in the case of BGA voids, at least. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Igoshev, Vladimir Sent: Friday, February 22, 2008 12:35 PM To: [log in to unmask] Subject: Re: [TN] Shrink hole voids Hi David, Think of rivets on a plane or ship. They are there to prevent a crack from propagating. A hole (or void) will do the same trick. It does not create a stress concentration (particularly in a ductile material like solder) and therefore it can stop a crack ("swallowing" it). You can take a look at the basics of Fracture Mechanics if you want to. Regards, Vladimir -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of David Tremmel Sent: Friday, February 22, 2008 1:29 PM To: [log in to unmask] Subject: [TN] Shrink hole voids Hello TechNet Gurus, I read an article that say that a shrink hole void (hot tear or sink hole) is not a crack, does not impact reliability, does not continue to grow under thermo-mechanical stresses. This seems to go against my common sense and would venture to say adds to solder creep fatigue. Would anyone like to comment on my comment and/or offer a link to where I can find more information? I am a poor country and your two cents goes a loooooong way. As always, thank you in advance. Thank you, David Tremmel Value Recovery 847 858-5540 - Cell 847 557-9574 - Office 847 557-9573 - Fax --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------