Prusa 3 Dual Extruder upgrade kit

thingiverse

This is the first in a series of upgrades that I will post soon with the changes I made to the original Prusa 3: Redesign extruder and carriage to mount a direct hotend and a Bowden hotend. All files modeled with Inventor are icluded to allow modifications in a compressed file. Also the Stls for direct print. (Caution: some STLs are not oriented in the correct position for printing) This is a x-carriage with 2 hotends supports (although in the photos are mounted only one). The block on the left is a complete direct extruder . On the right side there is a support for Bowden , so at the other tube end you must place the extruder you choose. Support for Bowden is designed to screw the pneufit adapter in plastic itself. Extruder and support are joined by two screws M4x65 or M4x70 threaded rod and associated nuts and washers. This binding is through elongated holes to allow perfectly level both hotends tips. The fan duct is for 40mm fan and what it does is to concentrate the air flow in the printing area of both hotends. This is complemented by a carriage carrying a lateral tab to fix one of the screws of the motor, which rests on the top of the carriage . Also has two M4 nuts accommodations that are used in the usual way to make the union stronger . One set is used for the extruder and the other for bowden support. If screws placed 50mm long , protrude from the rear which allows to fix the fan diffuser . The assembly is designed to mount two JHead with aluminum plates. Therefore at the bottom of the extruder is made the recess for JHead. On the bowden support side I have chose not to make this recess and make a piece to level . The fact that protrude perpendicular to carriage is because it is the space required to mount the hotends with top plates ( sinks ) . The system is not exclusive for 2 JHead indeed between CAD files I have included a support I called CatNozzle Bowden mount and is sized to permit the adjustment by combining a JHead at right and a Catnozzle at left. By my calculations this alternative support could also serve for the Prusanozzle . You have to choose one piece or another depending on the size difference of hotends you want to combine .