NEW VERSION AVAILABLE HERE:

https://www.thingiverse.com/thing:3716110

Introduction

This is a better extruder and X axis for Prusa i3 printer MK2(s), MK2.5 and MK3. It is a following of the Bear Upgrade project but is still compatible with original Prusa's 3D printers.

Features

Here is a list of improved features over stock Prusa extruder.

1. Improve print quality (reduce inconsistent extrusion) :
   • Lighter
   • Extruder motor is closer by 4.5mm to X rods to decrease the lever arm
   • Perfect filament path (check this issue)
   • Extruder body is much stiffer
   • Reduce flexing of X ends and X motor shaft
   • Optional: replacement of Bondtech "idler" gear by a 623zz bearing to eliminate gear meshing issue. See extruder_idler_bearing in optional parts
   • Hotend cooling improved (even better than Prusa MK3 R3 parts)
   • Self-centring of extruder motor
   • Bondtech drive gears no more at the end of the motor shaft
   • Includes hotend collet clip
2. Easier to maintain :
   • No need to disconnect cables from RAMBo to disassemble the extruder or access the belt
   • Z bearings installation made easier thanks to clamps
   • Simple and precise belt tensioning system with 3mm of adjustment
   • PINDA or the nozzle fan can be removed without disassembling the extruder body
   • Improved extruder body and cover assembly
   • No zip ties needed for X carriage bearings
   • Less screws
3. Perfect belt alignment and closer to top smooth rod to reduce lever arm
4. Filament sensor pocket improve filament detection and ease insertion of filament
5. Support Prusa MMU2 multi color system
6. Optional: reverse bowden to smooth movement of filament
7. Open source by providing STL and Autodesk Fusion 360 files (STEP file will come later)

Status

/! This is an ongoing development, not even a beta version for now. Use it with care. Any feedback is very welcome :relaxed:

Current version: 0.6.0-alpha

Ongoing tasks :

1. MK2s version
2. Fan shroud
3. Provide STEP files

Manual

The manual contains bill of material (BOM), print settings and assembly instructions.

Read the manual on my GitHub

Compatibility

/! This extruder and x-ends are matched to each other and cannot be used separately. As a unit, they are completely compatible with stock Prusa MK2.5, MK3, Bear Upgraded MK2.5, and Bear Upgraded MK3.

Optional parts

Official optional parts are here

Community

Here are the places were the Bear project is the most active. Do not hesitate to ask if you have a question :

• Facebook group : facebook.com/groups/PrusaBearUpgrade
• Discord server of "The 602 Wasteland" community : discordapp.com/invite/hYUjSnW
• GitHub : github.com/gregsaun
• Thingiverse : thingiverse.com/pekcitron
• Openbuilds community : openbuilds.com/builds/prusa-i3-bear-upgrade-v2.6428

Support my work

The Bear project is made possible thanks supporters. Here are some way to support me:

Become my patron with Patreon: patreon.com/gregsaunA tip via Paypal: paypal.me/gregsaunA tip via Thingiverse: thingiverse.com/pekcitron

Big thank you in advance <3

Thank you

Thank you to everybody from Facebook group and The 602 Wasteland community.

Thank you to all my Patreon : Anders Svendsen, Arnaud Christel, Barry from RC-CnC, Cristian Toma, Darren Furniss, Malo87, Mark Leino, Matthew Humphrey, Miguel Castillo, Orlando from all3dmakers, ra100, Sleene, Steven Daglish, Thomáš Vydra, Valentin Constantin, Vishesh from 3Dprintonics.

Thank you to all my tippers on Thingiverse : FurniBird, kabar03, Lucullus, NatDenkin, neofitos, Oggs, Ringo1508, TrevJonez.

Thank you for having purchased a kit from an official distributor.

Thank you Openbuilds for your hardware, community and state of mind.

Thank you to people that have helped me in the early days of the project : DoItWithSmile (jay3D), kabar03, xequtor and fishmsk, karlosek.

Thank you for all your comments and issues on GitHub and Thingiverse.

Thank you to Nathan Denkin for improving my english (I know it is not an easy task!) and for building a better assembly guide.

Credit, sources and inspiration

Here is a list of sources and inspiration :

• Prusa : http://www.prusa3d.com
• Zaribo : http://zaribo.org
• Vecko Kojchevski : https://www.thingiverse.com/vekoj/designs
• Arnaud Rousseau for "its X-Ends clamped MK3 (Zaribo)" : https://www.thingiverse.com/thing:2964026
• Prusa i3 Solidworks parts from jzkmath : https://github.com/jzkmath/Original-Prusa-i3
• Prusa MK2/S X-Carriage Adjustable Tensioner by Jon Madden : https://www.thingiverse.com/thing:2770019
• Jan Imrich from Kurzy Kocour maker space for all it's hard work on inconsistency issue
• The 602 Wasteland Discord server

Huge thanks to these projects, without them this project can not exist!