Vert-X-Belt-Truder (Q58527)

Early concept for a fully symmetric belt-driven extruder carriage for upgrading Prusa Mendel. Belt-driven means there's no stepper motor on the X-carriage, so it can be much lighter and move much faster. It has two X-belts that are controlled by one stepper on each side. If both belts move in the same direction, the X-carriage moves in that direction too. If both belts move in opposite directions, the extruder moves but the X-carriage stands still. x_motion = (stepper1 + stepper2) / 2 extruder = (stepper1 - stepper2) / 2 We'll need new firmware to control x_motion and extruder independently by setting the correct speed for each stepper motor for the two belts. stepper1 = x_motion + extruder stepper2 = x_motion - extruder This design attempts to reduce the effects of the torque that's required to move the extruder: * It is based on the excellent VertX (vertical x-axis) by watsdesign with LM8UU linear bearings: http://www.thingiverse.com/thing:10711 * It uses a pretty large timing belt pulley on the back of the carriage. * The two belts are entering the carriage very close together and perfectly parallel.