I can't rememver all I forgot on the subject. Before BGA days, in the middle to late 80's, I did some work addressing leaded and chip device voiding. I'll ask Steve to post a few images showing solder joint voiding in x-section. I had some from x-ray as well but the images have dissapeared. Anyway, some of us used the same rule (20%) for maximum voiding allowable after determining, in small quantities on a few boards, failures occured after very few mechanical and thermal cycles when the requirement was exceeded. It should be noted some of the solder thickness, between leads and solder termination areas, measurments exceeded the 1.5 times requirement then used. I don't know if this rule still applies but probably is. I'll get the pictures up for you if interested. They simply will complement your stuff. Earl --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 ---------------------------------------------------------------------------------