On our Quad, if we use only one local fiducial, the machine will use the
fiducial to correct for the X-Y location of the part when placing the it.
It will correct the theta placement based on the theta offset that it
calculated at the beginning of the placement routine when it checked the
global fiducials.

In my opinion, two local fiducials are better if the placement machine is
capable of using two.  



At 09:11 10/14/96 -0500, [log in to unmask] wrote:
>     Address,
>     
>     From past design reviews we have always used 2 fiducials per 15mil and 
>     20mil SMT devices (my opinion, standard). Recently our designers are 
>     placing 1 fiducial in the center of the device location.  I'm not an 
>     agreement with this change due to possible lead skew on pads and 
>     similar problems.  Has visual P&P equipment changed such, that 2 
>     fiducials are no longer required or none at all.  Please advise.  
>     
>     John Gulley  
>
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-Pat-

-------------
Patrick McGuine
Nicolet Instrument
[log in to unmask]
(608) 276-6334

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