Originally Posted by
freak_brain
When I started this process I went through all of the design possibilities, including the one you are talking about in your picture. That design, in my opinion, will not save you that much money and will prove to be more of a liability. It actually may cost you more money, two screws, two belts, a nema 34 motor etc.. The two motors and two racks work very well. and is easier than you may think to setup.
As for the "Z" axis. The reason for a "Z" axis on a plasma cutter is to maintain the proper torch heigth throughout any cut. Another words, it would actually follow warpped material by moving "Z" up or down.
Allen