Bob La Londe wrote:
Is there any reason why the gantry has to move on a CNC router? Seems
to me you could get a lot more rigidity by moving the table along one
horizontal axis instead. Then just move your Z axis assembly along the
gantry for the other horizontal axis, but have the gantry solidly bolted
to your table base. I realize it will take up more room when working
this way, but that's no different than a mill.
If the gantry moves, the machine only has to take up slightly more floor
space than the length of that axis. If the table moves, the machine
occupies TWICE the floor space for the same travel. That IS the
difference. No question whatsoever that a moving table and rigid gantry
is stiffer unless you go to insane extremes on the gantry.

Jon