Quote Originally Posted by hanermo2 View Post
Why will racking be an issue ?
A rigid center-driven gantry has perfect balanced push on both sides.
Can't see how the geometry of this works. Surely a centre-driven gantry is only balanced if you are cutting a slot up the middle of the bed? Making the gantry stiff enough probably is not a big problem, but the racking loads when cutting at the ends of the gantry are going to put big loads on the guide rails if you want to avoid significant deflection. After all, to be able to cut a 1200mm sheet, you probably want about 1300mm travel, plus width of Z carriage, so the gantry is going to be around 1500mm wide, putting the cutting load point around 700mm from the drive screw. So much easier to drive at both ends, which then allows a better bracing structure for the bed. Slaving two motors really isn't a big deal, after all. If I can do it, anyone can.