Here is the new Double Drive fitted to the Recreus Extruder. This pushes the flexible filament down into the hot end at the fasted speeds. The prints in the last photo were printed at 100mm/s on a Witbox in #Filaflex .
Both gears are grooved around the centre to allow the filament to pass through and not be crushed or stripped but still be contained sideways.
The idler tension is still adjustable too.
Nice! This beats out the Printrbot extruder I think. Adjustable tension, easy unload/reload etc is not lost with this design.
@ThantiK I believe so too, also better open airflow from extruder cooling fan (rotated out of shot) is important for flexibles.
Good job. Does it deform other filaments like the printrbot one?
@Stephanie_A No because the idler still has some adjustable sprung loaded tension.
Is it still just a groove in the normal gear teeth, or is it hobbed like a traditional filament drive gear inside the groove?
nice. Cost?
@Steve_Wood_Gyrobot Nice solution, i have been working on this problem myself quite a bit. Is the idler hobbed as well? Ar you printing 3mm filament or 1.75?
Well, it’s interesting. I’m still not convinced double driving a filament is beneficial though.
@Jeff_DeMaagd why would you need to be convinced? It’s simple physics. More surface area = more pushing power.
Because I haven’t seen the need. I don’t remember the last jam I’ve had. That extra force might even cause problems. If the nozzle’s jammed, these solutions aren’t going to help. A single hobbed pulley can and has lifted a 3D printer by itself. So where’s the need for a double?
I would prefer double traction for elastic filament. It tends to buckle very easily when pushed unevenly… Currently i resolved this by guiding the filament very closely (compacto extruder), but double traction would be the alternative.
OK, for balanced driving of flex makes sense. I don’t think there is a substitute for a close-fit guide though.
Will this retrofit to a FlashForge Dreamer?
@Jeff_DeMaagd Yes, Jeff, this is the solution for printing flexible materials, eg Filaflex at the fasted speeds.
Any testing with Bowden + e3d v5 hotends?
@Steve_Wood_Gyrobot , answer to @Whosa_whatsis ’ question? Hobbed on the inside? What does a side profile of the gear look like?
So the profile is similar to Printrbot’s version. Should be fine for flexible filaments, but I’m not crazy about the way that type of profile will deform harder filaments if there’s enough tension to do so, or the lack of grip if it doesn’t.
@Whosa_whatsis Is there any test you would like me to perform that might ease your concerns?
Well, I’d like to see what ABS and PLA filament look like after being run through it with the hot end removed.
