We have experienced an intermittent missing hole (not drilled) defect on
one part number.  On each of 20 panels I have analyzed, the same hole is
missing.
The entire drill file is intact on the mainframe, however, some kind of
glitch must be occurring either during downloading the data across the
DNC or executing the program on the drill machine.
We use Hitachi drill machines.
Has anyone run across such a problem, or does anyone have an idea what
might be the cause of this mystery?

drilbert