BondTech Prusa i3 MK2.5-MK3 Extruder Upgrade

This extruder upgrade kit is for the Prusa MK2.5 or the Prusa MK3, where you already have Bondtech gears installed. This kit contains the parts needed to convert the newly designed 3: 1 ratio extruder for improved precision and resolution, optimised geometry for the heatsink, and many other advanced features. It also reduces the moving weight to reduce vibration and ghosting.

The extruder is a collaborative development with great people in the Prusa community who have given excellent feedback and suggestions on how to develop the "perfect" extruder setup for the Prusa printer. Much work has been done in this project and an attempt has been made to listen to all the inputs to find a solution that can be adapted to a Prusa I3 MK2, MK2S, MK2.5 and MK3.

The extruder parts were made using SLS printed polyamide 12 for highest precision and strength.

The kit comes with a 25 mm pancake stepper, which guarantees 18 Ncm of torque for lightweight but powerful extrusion. Also included is a new cable for connecting the motor.

The following parts are used by the original Prusa and are not included in the delivery:

• Centrifugal fan 50x15 as printed piece cooler
• Hot-air fan 40x40x10
• Cover of the filament sensor

The E-steps have to be updated to 415 for MK2, MK2s and MK2.5. You can simply download the GCode file, put it on the SD card and print the esteps.gcode file to make and save the setting. For MK3, it must be 830 because it uses 32-bit microstepping.

The weight is reduced by 121 g.

This project is licensed under GPL V3 and the step files are available.