Hi Don,

After initially using a "bowtie" arrangement of .04 square pads, we switched
to a .060 diameter pad with a .125 diameter clearance in the solder resist.
We use this pad for both global, and local fiducials with good results.  As
someone else suggested, on multilayer boards, it's a good idea to keep any
other features, away from the fiducial until you reach the first plane.  I
use the resist pad as a keep out guide, and this seems to work fine.

Tom Hybiske
General Atronics Corp.
Wyndmoor, Pa.

> Technetters
>
> What is the best shape of fudicials relative to size and configuration?
Also
> if the board has HASL on all of the pads, can the fudicials be of
different
> material other than HASL? We are having a problem with reflective light
> causing a lot of rejected boards. This is also causing down time. What is
> the industry using for this technolgy. We have DEK 265 printers and
Philips
> and Siemens placement machines.
>
> Donn E Steffen
> Senior Quality Engineer
> VDO Control Systems
> Auburn, IN 46706
> Phone (219)925-8887
> Fax (219)925-8710
> Email: [log in to unmask]

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