From a fabrication process capability viewpoint, the size of the
    process panel is the dimension that should be used.  Multilayer
    lamination, drilling, image artwork registration (plating, etching, and
    solder mask) are all done with repsect to the process panel.  Most
    volume board farbicators today are able to meet a fabrication allowance
    number of .012 to .014" for an 18" x 24" process panel.

    DLW
    --------------------------------------

Reference IPC-D-275, para 5.3.2.3, Table 5-10

When calculating annular ring requirements, table 5-10 lists "Greatest
Board, X,Y Dimension".  The table uses this to list a manufacturing 
allowance.  The larger the dimensions, the larger the allowance.  Is 
this the actual board dimensions, or is it the panel size that is 
being used?

Thanks,
Tom Hybiske
General Atronics Corp.