Fiducials are used for an entire spectrum of reasons. a.. Design - The Fiducials can be used on an overlay in the design program and when printing check plots, ensures that the overlay was included. b.. Gerbers - Provides alignment marks to align check plots c.. Manufacturing - Helps the manufacturer align check plots, helps ensure layer alignment d.. Board checking - When the board is x-rayed for QC these marks help ensure layer alignment (this can also be helpful if re-inspected) e.. Assembly - These marks can be used for Autoplacement or as general alignment marks. Chris Robertson Author "PCB Designer's Reference" [log in to unmask] ISBN: 0130674818 ----- Original Message ----- From: Franklin D Asbell To: [log in to unmask] Sent: Tuesday, November 04, 2003 9:09 AM Subject: Re: [TN] I fiducial is an alignment marker(s) for pick-n-place type equipment. The fiducial is a known location in relation to features upon the board that will recieve components... Franklin --------------------------------------------------- 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 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- 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 847-509-9700 ext.5315 -----------------------------------------------------