True Ramon, But sometimes the pad layout is spec'd for a regular SOT14 or 16, and the only available part (due to obsolescence or whatever) is a narrow body component. Dealt with that a million times before. Jason Gregory Manufacturing Engineer Innova Electronics (281)653-5593 (281)653-5594 fax (281)594-0602 cell [log in to unmask] -----Original Message----- From: Dehoyos, Ramon [mailto:[log in to unmask]] Sent: Monday, March 06, 2006 2:35 PM To: TechNet E-Mail Forum; Jason Gregory Subject: RE: [TN] Heel Overhang Usually the components have leads that are quite larger than necessary. At part prep, someone decides what die to use to form the parts. It seems that the die use was not the proper one. The right prep is when the center of the feet are in the middle of the pad's length, at both ends of the component. Ramon -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Jason Gregory Sent: Monday, March 06, 2006 2:03 PM To: [log in to unmask] Subject: Re: [TN] Heel Overhang Kevin, In IPC-A-610 Rev. D, it states clearly, for Class 3, "Minimum heel fillet height is equal to solder thickness plus lead thickness." If you have parts where the pad layout spread is larger than your component, then the larger the difference will get you further away from the acceptable spec. Jason Gregory Manufacturing Engineer Innova Electronics (281)653-5593 (281)653-5594 fax (281)594-0602 cell [log in to unmask] -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Kevin Glidden Sent: Monday, March 06, 2006 10:29 AM To: [log in to unmask] Subject: [TN] Heel Overhang Hello again. Question on IPC-610 (class 3) criteria. For SMT solder joints, there appear to be criteria set for TOE overhang, but not HEEL overhang. Is this an oversite or a purposeful omission? Is there a limit on how much the heel of an "L" shaped SMT lead can be off the pad lengthwise? The obvious and defined limit is "does not violate minimum electrical clearance", but does anyone else have info on this criteria? Thanks again, Kevin Glidden --------------------------------------------------- Technet Mail List provided as a 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/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 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/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 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------