Proper Extruder

Suggested price: 3.00

The download contains the 3D printable (stl) files only. The Fusion 360 and/or STEP files are accesible to my Patreon supporters. Consider becoming a supporter yourself and get access to these files!
The download contains the 3D printable (stl) files only. The Fusion 360 and/or STEP files are accesible to my Patreon supporters. Consider becoming a supporter yourself and get access to these files!


This is an experimental extruder that uses timing belts to push the filament. The idea is based on the filament manufacturing process and I miniaturized this. This is in its experimental stage, so things might change, but it seems to work very well. I managed to print the world’s most flexible filament with it!

Print settings

Printer: Anycubic Photon*
Rafts: No
Supports: Yes
Resolution: 0.05*
Filament: 3DResyns PMMA-like or PEEK-like resin*


*These are settings for resin printing which is recommended. However, it’s designed in such way that it’s printable on an FDM printer. Since the motor needs quite a lot of force to print reliably and it can’t get rid of its warmth, it’s recommended to use ABS, Nylon or polycarbonate for the motor bracket. Chances are that this can be mitigated when using it in a bowden configuration by mounting it on the standard aluminium mounting plate (standard Creality printers) between the motor and bracket. This is not yet verified!

The FDM version of the base plate has a custom support around the circumference. This way, the base plate can be printed with the flange needed to print the flexible filament. This support can be removed with pliers and a knife. The picture below shows the bottom view of this part with the proper orientation:

If you don’t need the flange it’s recommended to print the resin version with the base itself touching the build plate and the flange facing down through the build plate.

The picture below shows the right orientation for all parts

I oriented all resin printed parts flat, 5mm floating above the build plate. Basically the same orientation as the logical FDM print orientation. This puts more stress on the FEP-film, but results in better prints in my experience. This makes it possible to sand away the left over support with waterproof sandpaper (400-800). The picture below shows an example of the orientation I use:

I use Lychee slicer and if you have questions, leave a message on the about page.

Parts needed & tools required

All 3D printable parts must be printed once except for the coupler gear (2×) and modified pulley (4×). There are two variations. One which uses specialized parts and one which uses standard parts.

QTY Description Link*
13 MR85ZZ Miniature ball bearing
1 Stepper motor
7 M3 brass insert
2 M6 brass insert
2 2GT 110mm Closed loop timing belt
2 GT2×6mm driven pulley with bearing
2 GT2×6mm 20 teeth pulley
3 M5 x 14mm screw
3 M5 x 20mm screw
5 M3 x 8 countersunk screw
2 M3 x 16 rounded head screw
2 M3 x 8 rounded head screw
6 M5 nut
2 M5 x 30 heax head screw
2 M3 x 6 Set screw
1 Loctite 406 super glue
1 Loctite 243 threadlocker

*Commissions are earned from the links above which help funding this project. If you have found a better alternative for a component, please let me know!

Required tools

  • Allen key set
  • Press or vice
  • 2mm, 3mm, 4mm and 5mm drills

Mounting instructions

General notice: All holes for the inserts are designed to be glued and pressed into place without using heat. This way it’s more accurate and the inserts can be placed in resin printed parts. Pressing and gluing the inserts before curing the parts is recommended.

  • Use the 2mm drill to drill out everything related to the filament path (front plate and hotend holders) Do this as accurate as possible!
  • Use the 3mm drill to drill out all 3mm holes there the M3 screws go through
  • Use the 4mm drill to drill out the holes for the M3 inserts (use extra care for the bottom two on the front plate manual drilling is recommended)
  • Use the 5mm drill to drill out the three holes in the base part where the shaft of the motor goes through and the bolts for the coupler gears.


  • Prepare the base part
    • Press in the bearings (only glue is required for the single top bearing for the motor) Roughen up the circumference of the bearing and apply the super glue carefully.
    • Press and glue in the nuts or flat inserts.
    • Mount the top left custom pulley with the M5×14 screw and a drop of threadlocker. (ensure a smooth movement)
  • Prepare the front plate by pressing and gluing in the bottom M3 inserts on both sides
  • Prepare the motor bracket by gluing in the M3 inserts
  • Press the bolts in the coupler gears
  • Place the coupler gears on the base part and add the 20 teeth pulleys with the teeth faced towards the base part. Fasten the set screws and ensure smooth movement.
  • Place the M5×20 screws in the front plate and place it on the table with the threads facing up.
  • Add the custom GT2 pulleys with the bearings together with the belts. (the idea behind the flat side was to make sure that the belt could be removed while the pulleys are still on there which was needed for the first prototype. This has no function). The bottom two pulleys should stay in place due to the belts.
  • Carefully place the front plate assembly on the base part. Place the belts on the 20 teeth pulleys first.
  • Add the two driven pulleys with two M5×14 screws and a drop of threadlocker. These act as spanners. Ensure a smooth movement and let it dry for 10-15 minutes.
  • Press on the pulley knob and fasten it with carefully the set screws (optional)
  • Press the motor gear on the motor as far as possible without binding. If the flat edge doesn’t go far enough it’s recommended to press the shaft of the motor itself further in.
  • Mount the motor to the motor bracket using 4 M3×8 countersunk screws.
  • Mount the motor assembly to the base assembly carefully (use your thumbs at the upper bearing where the shaft of the motor goes.
  • Make sure that the bracket sits flush against the back of the base and fasten the top with an M3×8 countersunk screw
  • Mount the belt pushers with the M3×16 hex socked or rounded head screws to the bottom holes after manually feeding some filament (this ensures parallel positioning)
    • Mount using two M3×8 countersunk screws instead if you don’t use the pushers
  • Mount the tool holder
  • Mount the whole assembly to the printer

Other tools

The bottom of the front plate is designed as an adapter mount. This enables to fit multiple after market hotends. At this moment, only a bowden adapter and CR-10 stock hotend adapter is available. It’s recommended to use the bowden adapter, also for a direct drive setup. You can place the extruder directly above the hotend with a short tube. The idea is to develop several mounts with different mounting options. There is a STEP file added to the download of a blank tool holder, so you can develop your own for your specific setup. I’m going to post updates on Twitter if I developed a new mounting system so make sure to follow me!


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