Hi Peter, By definition, for holes in Printed Circuit laminates with LANDS or PADS, a supported hole has plating in it or an Eyelet to support the hole thus providing mechanical support to the hole structure. By contrast, a non-supported or un-supported hole does not have plating in it. Mechanical mounting holes are typically non-plated, un-supported holes. Tooling holes most commonly have no pads or plating in them. Vias are typically supported holes with plating in them. Hope that clears it up... Bill Brooks PCB Design Engineer , C.I.D., C.I.I. TITAN SYSTEMS CORPORATION DATRON WORLD COMMUNICATIONS DIVISION 3030 Enterprise Court,Vista, CA 92083 Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510 Adjunct Instructor - PCB Design Palomar College, 1440 West Mission Road San Marcos, CA 92069-1487 http://www.palomar.edu/ Member of the IPC Designers Council http://dc.ipc.org/ Executive Board Steering Committee Education Committee San Diego Chapter of the IPC Designers Council Core Group Board of Directors, Communications Officer and Webmaster <http://www.ipc.org/SanDiego/> <http://home.fda.net/bbrooks/pca/pca.htm -----Original Message----- From: Peter Lee [mailto:[log in to unmask]] Sent: Tuesday, June 25, 2002 12:22 PM To: [log in to unmask] Subject: [TN] Definition of Suported/ unsupported hole Technet, Can anyone explain the difference between a supported and unsupported hole on PCB? I am reading a section on IPC-A-600 RevF and section 2.10.3/4 specify difference acceptance criteria according to the hole type. Rgds, Peter ---------------------------------------------------------------------------- ----- 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 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 ---------------------------------------------------------------------------- ----- --------------------------------------------------------------------------------- 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 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 ---------------------------------------------------------------------------------