Whoops!!! Typo, should indeed be stating 0.050" diameter. No, a 5 thou fid would not be good... regards, - Graham -----Original Message----- From: [log in to unmask] [mailto:[log in to unmask]] Sent: Wednesday, June 04, 2008 10:00 AM To: TechNet E-Mail Forum; Collins, Graham (FN) @ ESI Subject: Re: [TN] Fiducial solder resist clearance Did you mean a .050" dia fiducial? curious. We make "simpler" assemblies and use a .050" circle for fid. The rest of the world may actually use a .005" fid. Lenny ERG www.ergpower.com ----- Original Message ----- From: "Graham Collins" <[log in to unmask]> To: <[log in to unmask]> Sent: Wednesday, June 04, 2008 6:35 AM Subject: Re: [TN] Fiducial solder resist clearance Good morning Douglas (OK, good afternoon in the UK). We (as builders) insist on 2x the fiducial radius to ensure a good vision check. We prefer a round fiducial, .0050" diameter. Not having a good fiducial usually isn't a show stopper, but will aggravate the assembly people as it means manual intervention to align the machine to the board. Obviously the finer the pitch the more problematic this can be as a manual alignment can be "close" but usually isn't quite as good as if the machine finds it. Worst fiducials I've worked with - a designer had the brilliant idea that the fiducial should double as a ground point, so all fiducials were drilled and plated through to connect to the ground plane. Essentially then the fiducial was a big via. Great for troubleshooting, but a royal pain in the butt for us - after first reflow the HASL solder in the via would flow down, so each fiducial would have it's own unique dome shape - whereas we were looking for a nice flat surface. Aaaggg!!! regards, - Graham -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Douglas McCall Sent: Wednesday, June 04, 2008 7:14 AM To: [log in to unmask] Subject: [TN] Fiducial solder resist clearance Hi, When desiging the PWB for fiducials, what is the experience of having the solder resist up to the edge of the fiducial pad. If the recommended clearance window round (2-3 x fiducial radius) the fiducial is not maintained does this in general cause excessive vision system problems, - looking at the solder resist compared to looking at the laminate material. I understand that this clearance should be left with no resist and leaving the bare PWB laminate and etched fidicial feature. What is the prefered fiducial shape used by most designers? Thanks in advance for any information. D. McCall. _________________________________________________________________ Great deals on almost anything at eBay.co.uk. Search, bid, find and win on eBay today! http://clk.atdmt.com/UKM/go/msnnkmgl0010000004ukm/direct/01/ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 15.0 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 15.0 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 -----------------------------------------------------