Filament mixer / dual extrusion / mixing extruder

thingiverse

updated 11/9/2016 - added versions for M5 and BSP1/8 threaded PTFE coupler, and a holder to stop the mixer from tilting. designed to turn any single bowden hotend setup into a dual extruder setup, just need to add a second extruder. If you use this setup you dont need to calibrate nozzle offsets as its using the one nozzle for both filaments Need to use some gcode to manage the filament changes otherwise straightforward to assemble, print 2 copies of the body, and assemble using 3x m5 bowden ptfe couplers. The idea is that when you need to do a filament change, you need to back out the filament into the filament mixer, then push the second filament in, purge, then continue. Note this is for 1.75mm filament GCode i used in the tool change script in simplify 3D as follows. No doubt will need to tune for your setup as far as how far to retract etc, just note its always better to retract a bit further than you need, than not enough. Works fine for PLA and PETG, my stringiest filaments, havent tried TPU yet, suspect i may need to polish the inside of the mixer for it to work properly. ---SNIP--- T[old_tool] G92 E0 G1 E-30.000 F3600 ;fast initial retract G1 E-50.000 F300 ; slow down the retract let the filament cool a bit to reduce strings G1 E-120.000 F3600 ; back out the remaining distance to clear the mixer, youll probably need to tune the length on this for your setup G1 X150 Y0 F7200 ;go to purge position so you dont squirt filament all over your work T[new_tool] ;purge new tool G92 E0 G1 E120.000 F900 ;push the new filament into the hotend G1 E130.000 F450 ;slow down the push as it enters the heater block G1 E150.000 F200 ; purge the nozzle, probsbly more than required :) G1 E148.000 F1800 ; small retract to encourage the purge to snap off G92 E0 ---SNIP--- My setup is a e3d lite using a pair of these extruders http://www.thingiverse.com/thing:1708020