An improved Flexible Filliment Extruder

This is just a little preview of my new project. It’s not finished yet, and there are still a few things to clean up on the STL files, but there is enough done that you can see the general idea. This is a belted flexible fillament extruder, which uses the Bondtech 2.0 extruder core dual hobbed wheel kit as it’s core ( .

Some theoretical improvements:

  1. Double the extrusion force on flexible filliment before stripping will allow for faster printing
  2. A belt drive system is more compact, but delivers about the same amount of torgue as the greg / wade style gear system, but with zero backlash.
  3. The motor may be turned and tucked in closer to the main extruder body, so the lower filliment path may be shorter by 5mm, which should improve extrusion speed and quality
  4. The dual hobbed wheels eliminate one of the wear points of the PTFE tube. The steel inlet cap will eliminate most of the rest, which means this extruder may be suitable for ABS and PLA
    The larger diameter hobbed wheels allow greater surface area contact with the filliment even without the second wheel
  5. Cleaning ports on both side, as well as a removable side pod to access the middle.
  6. Theoretically approximatly the same weight as the stock flexystruder since the belt system weighs less than the gear setup, the unit is shorter, and the tensioner for the belt system only adds back a few grams over the weight of the normal motor mount.

Known disadvantages:

  1. It’s about 10mm thicker than the stock flexystruder, which will require a different carriage. This is due primarily to the height of the hobbed wheels.
  2. Component cost is higher by $60.

I have the parts now, I just need to finish the design work and print it to test it out. Then I need to figure out what I want to do with it.

Here’s the prototype. It will definitly need it’s own carriage, which isn’t finished yet. But the basic concept seems to work. I will need to reinforce the side lugs a little bit more to take the force of the filliment, but most everything lines up, both hobbed thingies turn, the belts fit, the belt tensioner works, etc. I’m waiting on drill bits to install PTFE tube. The bore hole may be about 1mm off at the moment too, but that will be easy enough to fix.

It’s wide enough that it does require a special extruder carriage to fit properly. Not a big deal to generate though, so here it is!

Drill bits haven’t arrived yet to install the PTFE liner, nor have my second set of fans, but aside from that it’s functionally complete. I guess I also need to figure out where to buy a 0.6mm nozzle end too.

this is looking really nice! I JUST finished assembling my own flexstruder using the hexagon hotend, all I need to do now is print a shroud for the fan blowing on the heat sink and figure out where to buy the end to crimp onto the hotend heater and heat sink fan. speaking of which, where did you get yours?

Thanks! I got the crimp ends and housings from digikey. My fans have been sourced from ebay or

The shrouds are a mix of a stock lulzbot one I printed back when my machine was a taz 3, and the blue one which is my adaptation of wolfies fan design.

thank you, but what was the actual part number? I can not seem to decode the BOM. also where have you been getting the 0.6 nozzle from?

Here are the part numbers and descriptions from my order
WM2510-ND 0016020102 CONN TERM FEMALE 22-24AWG TIN
WM2565-ND 0016020108 CONN TERM MALE 24-30AWG TIN
WM2902-ND. 0050579404 CONN HOUSING 4POS .100 W/LATCH
WM2535-ND 0701070003 CONN HOUSING MALE 4POS .100

You may also want some of the 2pos housings for fans.

I have not yet located a 0.6mm nozzle. I may have to make one.

Got the teflon liner in today. Everythign lines up great and seems good to go. I also think that i’ve held of posting the STL files long enough to make my point: People post designs here because they belive in the company and the community. They don’t “Have” to. Counting the 2 weeks I was dead in the water with the flu, this is 4 weeks in design and development from start to working prototype. Ok, I’m done with the soapbox, it is what it is.

Anyways, here are the STL files.
Improved_Flexystruder_body_1_0_b.stl (1.2 MB)
Extruder_Mount_1_Blower_duct_3_0_b.stl (459 KB)
Extruder_Mount_1_Blower_Duct_Return_1_0_a.stl (156 KB)
Improved_Flexistruder_tensioner_1_0_a.stl (69.8 KB)

And the rest.

Instructions and material list are here:

Improved_Flexystruder_Side_pod_a_1_0_b.stl (240 KB)
Improved_Flexystruder_Side_pod_b_1_0_b.stl (174 KB)
Taz_flexystruder_carriage_1_0_a.stl (785 KB)

How would this work with normal filament such as ABS?

I plan on putting a steel liner at the top, so between that and the pinch rollers, it should actually work quite well. I’m working on a standard filliment variant as well too though.

very very nice, have you had any luck with the 0.6mm nozzle? I have yet to find one, but I have a drill that will hopefully dot the trick, I plan on ‘brassing’ the drill and then drilling out the existing nozzle soon. any advice?

E3d V6 nozzles will fit the Hexagon body. I ended up buying an E3dV6 brass 3mm filliament 0.6mm nozzle from matterhackers, which works great so far.

rock on, I’m ordering it right now!

Just dropped by to say that I ordered the E3Dv6 3mm fun pack (0.25, 0.30, 0.35, 0.40, 0.60, 0.80 mm nozzles) for $48 from Matter Hackers, and within 17 minutes of receipt of payment it was shipped out the door. Amazing.