XY Translator
The XY translator before the addition of optical end-stops.
The XY translator is based on the clever cable-based linear translation system implemented by Ilan Moyer in his FoamCore CNC Project. It took just a day and a half of work in the machine shop to create a functional prototype. I employed 1/2" MDF as my primary structural material because of its high tolerances and the ease with which it can be worked with simple tools. I cut the square frame and the motor mounting blocks on a table saw and used a vertical mill to remove material inside the frame. I assembled the motor mounts with super glue and threaded rod and lined the perimeter of the frame with Teflon tape to reduce friction from the riding motor mounts.
Details of a motor mount showing the cable-based linear motion system.
I used reamed nylon bushings to create primitive, but very effective roto-linear "bearings" for the simple translation head. The bushings ride on 1/2" drill rod that is driven on one end by a stepper motor. The end of each gantry shaft has been reamed to the diameter of the stepper motor shafts and has a threaded hole to allow the shaft to be secured by a setscrew. Because the wrapped, tensioned cables prevent linear translation in the plane of the frame, the torque from the motor results in rotary motion of the shaft, which causes it to roll.
