Feb 9, 2014

RepRap X2V3 3d printer with two independently moving extruders

RepRap X2V3 is the new generation of the RepRap X2 dual extruding 3D printers line. It features two independently moving extruders on X axis, so you can print in two different colors or types of filament (base and support material).

Hardware features:
  • Support independently moving X axis carriages for 2 extruders
  • Nozzle wiping / cleaning 
  • Frame modifications allowing X stage to move higher
  • Printing area casing
  • The hardware design is similar to RepRap X2 (that is based on SAE Prusa's Mendel), but X2V3 has to be slightly wider and therefore requires some of the metal rods to be longer (basically all the rods that are positioned horizontally).
Firmware features:
  • Dual X or Y drive machines support
  • Support for simultaneous duplicate or mirror printing
  • Filament compression compensation (experimental)
  • Various new and existent command improvements

Independently moving X axis carriages for each extruder hotend
Typical dual extruder machines have both hotends located on the same carriage. That design has several disadvantages like idle extruder leaking plastic or catching and knocking off the printed object. RepRap X2V3 has two hotend carriages driven by independent motors of X axis. While one hotend is printing the other one can be positioned it its docking space away from the "action". The independent drive also allows to utilize all the available platform space for the "follow-me" mode for printing two identical objects simultaneously. Each carriage has its own independently controled hotend fan.

Nozzle wiping/cleaning capabilities
The docking positions for hotends are at the ends of the X stage. The nozzles are cleaned when hotends are sliding over cleaning element on the way back to the printing area. The silicone tube piece with triangular cut on the side where nozzle slides over the tube to get cleaned is used on my machine. Mounting of other cleaning mechanisms can be easily achieved. This feature allows priming the extruders minimizing leakage and inconsistent startup of the extrusion when switching to the hotend being idle for a while.
Frame modifications allowing X stage to move higher
The triangular pieces of the frame (sides) are changed from being equilateral to get wider at the top. That allows X stage to move up all the way over Z threaded rods without being blocked by the frame structure. This adds 10-15mm to the height of the printing area without other dimensional changes of the machine.
0.35mm hotend nozzles
The 0.35 nozzles have been used on various RepRap machines for a while now. Switching to the smaller nozzle diameter allows slightly smaller detailers to be printed reliably.
Printing area casing
Printing area casing helps a lot to avoid heat dissipation from the heated printing bed and helps to keep heat from external source (I'm using 125Wt heat lamp) inside in the printing area. I've been using casing for a while now. Initially it was done from coagulated cardboard (that can be done for a typical Mendel machine under an hour). After it has proven to be useful the cardboard plates were swapped to acrylic for the RepRap X2V3 machine.
Motor fans
The 50mm fan mounts used on the RepRap X2V3 allow to attach fans easily to any of the machine motors. I'm currently using fans on the extruder and Y axis motors. The Y axis motor fan blows air away from the motor and out of the printer casing while the extruder fans blow onto the motors.

x2v3 homepage with in-depth descriptions of all components:

Thingiverse page with all the files: