Hi Dave, >Ioan - I have seen two very distinct camps of though on solder joint voids: >one camp believes that solder joint voids behave in a classical manner- >the void "blunts" the crack propagation and slows down the growth of the >crack; the second camp believes that the solder joint voids do not >participate in crack propagation in any form. Actually, the 2 camps you perceive are not mutually exclusive. Chuck Schmidt of SRI showed that the vois to in fact blunt crack propagation. However, the blunting is very local--remember, unlike the crack in a bell being stopped by a hole drilled at the whole of the crack tip--, the void occupies only a small part of the total crack front. Thus, the blunting is limited to the very local area of the void, and as soon as the crack front goes beyond the void, the crack front retardation at the void rapidly catches up with the rest of the crack front. Thus, voids both 'blunt' crack propagation but because of the local and temporary nature of the 'blunting' they make any real difference. Best regards, Werner Engelmaier --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------