Electronics Forum | Wed Aug 17 15:30:56 EDT 2005 | DannyJ
Hi Jaya, Here's a definition, towards the bottom of the listing... http://en.wikipedia.org/wiki/Fiducial Mainly, a 'global' fiducial refers to the outside of the board, usually on the scrap rails. This allows the machine to locate two reference
Electronics Forum | Fri Oct 20 08:55:48 EDT 2006 | nodlac
Hi Steve- Not being familiar with CS machines as you are...but do you need to use fiducials for a 20mil QFP? If so...OK...just curious. Also, it would be nice to know the reference point that the board designer uses... Board corner, Centroid, part c
Electronics Forum | Thu Oct 19 13:38:29 EDT 2006 | SWAG
We use random local fids on our Universal equipment - (they don't create a centerline placement point). On your equip., maybe you could try to shoot/dive-bomb the QFP(s) all by themselves using the 2 "random" local fids as your baseline reference po
Electronics Forum | Thu Oct 19 14:20:18 EDT 2006 | sliebl
Something that I find unusual in some of the replies is the fact that local fids that are randomly dropped around the quad don't do anything for assisting the alignment of said quad. The only way that I am aware of the local fids being useful is if t
Electronics Forum | Mon Jun 13 09:17:05 EDT 2005 | russ
Some machines may require that the two locals be used to calculate a center point where some (probably most) just use them as a second positional identifier. The fiducials are programmed as just XY and just prior to placement the machine will read th
Electronics Forum | Thu Jul 01 11:29:32 EDT 2010 | swag
We build thousands of flex boards in array format. The fiducial quality for both global and local fids give us much trouble and it seems to be inherent of flex PCB mfg. I am trying to write an internal ducument for our PCB fab house to adhere to.
Electronics Forum | Thu Feb 18 17:29:54 EST 1999 | Stefan Witte
The circle is not a "good" fiducial. The gradually change in contrast of a circle versus a cross makes it difficult to find the center of the fiducial. By pre-tinning the fiducials there will be a convex mirror surface distorting the edges even more.
Electronics Forum | Tue Aug 02 15:03:37 EDT 2016 | davef
On a previous black pad experience we soldered a wire to a fiducial and did a pull test to failure. On the black pad board the wire and solder pulled of clean leaving the fiducial on the board. On good boards the copper came off with the wire. If you
Electronics Forum | Tue Sep 06 12:39:06 EDT 2011 | deanm
According to IPC-7351A, the optimum fiducial is a solid circle with a minimum of 1mm diameter, but can be up to 3mm. There should be a solder mask clearance a minimum of 2x the radius of the copper circle. So the minimum fiducial size is 0.040" with
Electronics Forum | Wed Jun 15 00:33:11 EDT 2005 | Frank
You didn't state if you are using all CAD data or not. If you are not using any CAD data then all bets are off. If you global fid XY data and all your placement XY data are all from CAD data, but you are manually teaching your local fids, then they
