I have an upcoming high volume product that requires a very tight 
     tolerance on the bare PCB.
     
     I need to locate the center of 3 non-plated holes of 2mm diameter to 
     +/- .004" X/Y tolerance to an etched feature. 
     
     The etched feature is square and is on one of the outside layers of 
     the board.  
     
     These holes are used to mechanically align a component to copper 
     features on the board.
     
     Improper alignment will result in massive shorts or opens.
     
     My questions are as follows:
     
     1.  For standard processing what tolerances are typical for NPTH to 
     etch feature registration on a PCB.  My experience is that it is 
     somewhat greater than +/-.004" for standard processing.
     
     2.  Is there special automated equipment (or a process technique) that 
     is available for high volume production (i.e. more than 10K per month) 
     that can improve this tolerance?  For example I have heard of optical 
     drilling equipment that can drill a hole with great precision relative 
     to an etch feature, much like a pick and place machine locates a SMT 
     part to a fidicual.  I've "heard" of it, but never seen it or talked 
     to equipment manufacturers.
     
     3.  Is there any equipment out there that can measure this dimension? 
     (i.e. the center of a non-plated hole to the center of a square copper 
     pad).
     
     I'd appreciate any insights or comments.
     
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