Current state: Alpha release and testing
Papilio, Latin for Butterfly.
What is the Papilio Extruder?

No metal teeth biting into the filament, but soft rubber belts pushing the filament down to the nozzle. This is the concept of the Papilio: An Extruder which uses regular 2GT timing belts instead of metal gears to feed the filament.
You may wonder why we need an extruder that uses belts instead of gears? Guess it’s fair to say, that we all know the woodpattern on flat surfaces or the small bites on the filament when the metal gears grab the filament. With the belts there are no teeth damaging the filament, but soft rubber pressing against the filament that also act as a perfect guide for the filament all the way through the extruder. As all my projects the Papilio will be a 100% opensource project.
How does it work?
Powered by a Nema 14 the Papilio uses a 50:10 (or 50:8) reduction to drive two tiny 2GT timing belts. In order to keep everything as minimalistic and cheap as possible the Papilio uses very common parts like the BMG Drive Gear assembly, GT2 Idlers and Pulleys.
The Nema 14 doesn’t make it just super compact but also very light weight – only 140g!
The Papilio uses a Dual-Drive System so the filament gets pushed on both sides by the two timing belts.




Alpha Testing – How can I try this out?
The Papilio is currently in a closed Alpha-Testing with limited/controlled access to the files. This is to get a controlled launch of the Papilio and improve the design before it gets published. If you want to join the Alpha-Testing I highly appreciate your willing to help.
As for all my Beta testings the Alpha-testing will happen on my Discord – check the channel “How to become a Papilio Alpha-Tester” for more information. Note that the release is limited to given number of testers to keep things organized.
Click on the icon to join my Discord Server:

Are there any limitations?
- Using the BMG drive shafts makes the assembly quite thick. While the extruder body itself is only 21mm thick, the shafts stick out additional 7mm, giving the whole assembly a thickness of ~28mm. Using custom hardware or (SLA) printed gears could make the assembly even thinner. Due to the thickness the Papilio doesn’t work with the popular Voron Stealthburner at the moment – I’m using a Papilio with a Stealthburner with different hardware already, but this isn’t part of the Alpha release yet and still needs some fine tuning.
- The Nema 14 is a small but not so powerful motor and at the same time the belts add a lot of friction. Therefore a transmission was needed that generates the required torque to push the filament. While the LDO1 Nema 14 often gets called a prototype the Moons Nema 14’s are a very different story – small but powerful. With the 10T Moons Nema 14 I get a flowrate of ~12-13mm³; with the 8T Moons Nema 14 ~22-23mm³ depending on the filament (tested with a Rapido UHF). I’m currently working on different Papilio versions which will use different and/or custom made hardware to get a higher gear ratio and therefore more torque. I will keep you updated!
- So far my testing with flexible filament has been semi successful – the open design of the extruder gives the filament too much room to escape (Not only the front but also the back towards the Nema). I already have ideas how to solve that, but so far I mainly focused on daily printing with non-flexible filament.
- Since the Papilio is a printed extruder you need somewhat of an accurate printer – nothing too crazy, my Ender 3 printed dozens of Papilios already but you should be familiar with tuning procedures like this: Ellis tuning Guide.
1 Therefore the LDO Nema 14 is not supported.
What’s planned already?
- Papilio Pro: A version which uses custom made hardware to get a light weight and very powerful extruder
- Papilio Lite: Inspired by the LGX lite this version will use some of the LGX internals to gain a smaller formfactor for Stealthburner
- Papilio Bowden: Of course there will be a bowden version of the extruder for your bowden setup – powered by a Nema 17