Prusa I3 MK2/MK2S extruder upgrade



Prusa I3 MK2/MK2S extruder upgrade

This extruder upgrade is for Prusa MK2 or Prusa MK2S

Includes Bondtech Drive Gears

This kit is for users that also require the Bondtech Drivegears.

Save weight and print faster

This kit contains the necessary parts to convert to our newly designed extruder with 3:1 gearing ratio for better precision and resolution together with optimized geometry for the heatsink cooling and many other cool features. I also lowers the moving weight to reduce ghosting and vibrations.

Available on backorder

  • With the new Add-On this kit also supports MK3s filament sensor.
    Download the files for the printable Add-On here:

    Co-developed with the community

    This is a co-development work with awesome guys in the Prusa Community like Chris Warkocki, Grégorie Saunier (Bear Upgrades), Olof Ogland, Erik Bjorgan, Josh Jones, Kyle Wiehe, Marc Evertz, Matt Harrison, Ocie Ward, Sando Bendig, Vecko Kojchevski (Vecko Extruder), Steven Mölby that have provided excellent feedback and suggestions of how to develop the “perfect” extruder setup for the Prusa series printer. A lot of work has been spent in this project and we have tried to listen to all the inputs in order to find a solution that can be fitted to a Prusa I3 MK2, MK2S, MK2.5 and MK3. The extruder parts are not optimized for FDM printing but for SLS printing that we use to produce the housing parts in polyamide 12 for maximum precision, strength and temperature resistance.

    Light weight stepper motor included

    This kit comes with this 25 mm pancake stepper that have 18 Ncm in torque for a lightweight but powerful extrusion and a new stepper cable for connecting the motor.

    Original Part-cooling fan is replaced

    The original part-cooling fan 50×15 radial fan used in this setup and is not included.

    This setup is made to use a 40x40x10 heat-sink cooling fan that needs to be purchased separately, it is not included. The original heatsink cooling fan on MK2 and MK2S is 30x30x10 and will not fit.

    Filament sensor cover

    A FDM-printed filament sensor cover is included.

    For MK2, MK2S and more

    This extruder will fit the stock MK2 and Mk2S carriage’s and also other popular designs like MK3, Vecko, Zaribo and Bear. Check the guide for available X-Carriage here:

    Firmware change required – new E-Steps value

    The E-steps needs to be updated to 415 for MK2, MK2s and MK2.5 and is easy to do by downloading this g-code file, put it on the SD card and select to print the file esteps.gcode which will set the esteps and save it. For MK3 it needs to be 830 as it uses 32 bit microstepping, use this file instead.

    Huge weight reduction

    Weight reduction is 121 g, from 387 g as default setup compared to 266 g for this setup (Extruder, steppermotor)

    This project is licenced under GPL V3 and the STEP-files are available here.

    Prusa table


    To use the MMU2s together with the Bondtech an extra Add-On is required. This will allow sensor to trigger once the filament is reaching the drive gears.
    You can download the STL file bundle here: MMU2s Add-On for Bondtech MK2/MK2s.
    All credits to Leon Van Roosmalen for his amazing design. Find more information about his work and designs here:

Additional information


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