2 Extruder Mod for Prusa Mendel

thingiverse

This Prusa Mendel 3D printer mod uses Makergear hotends and Greg Frost's extruder design v3 with firmware based on Marlin, RAMPS v1.4 electronics. Extruders are mounted on the sides of the printer via PTFE tubes (A. Bowden's mount) and filament is driven through these tubes. The mod works best with 3mm filament but can also use 1.75mm. Instructions involve printing two extruder mounts, adapter, hotends, and a second extruder body (mirrored version for symmetry). Hotends require force to securely snap in place. Filament drive tubes need 2 feet PTFE tubes from mcmaster.com part #52365K611. Extruders must be at least 435mm treaded rods on top of the printer for mounting. Hotends are leveled by holding PEEK mount with pliers and adjusting nozzle/heater barrel. Electronics require additional wiring for second extruder, hotend heater connected to D9, and termistor to TERM2 pin. An external fan control board is needed if you want to use the hotend fan. The modifications are done on Marlin firmware with Configuration.h edits and building the firmware. Major commands related to multiple extruders setup include T, M104, and M105. A software package, X2SW, installs Printrun, Slic3r, and sets them up to work together using RepRap/X2/x2_0200 experimental profile. Retract speed is very important for this kind of filament drive and the mod is mostly used for switching between 0.5mm and 0.35mm hotends or between ABS and PLA. Switching between PLA and ABS for printing support vs object didn't give better results. The first attempt to print something useful in multiple colors resulted in this: http://www.thingiverse.com/thing:17670