# Bear Extruder And X Axis
## 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
...显示更多 Upgrade project](https://github.com/gregsaun/prusa_i3_bear_upgrade) 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](https://github.com/prusa3d/Original-Prusa-i3/issues/51))
* 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](optional_parts/extruder_idler_bearing)
* 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
1. 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
1. Perfect belt alignment and closer to top smooth rod to reduce lever arm
1. Filament sensor pocket improve filament detection and ease insertion of filament
1. Support Prusa MMU2 multi color system
1. Optional: reverse bowden to smooth movement of filament
1. 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
1. Fan shroud
1. Provide STEP files
## Manual
The manual contains bill of material (BOM), print settings and assembly instructions.
[Read the manual on my GitHub](https://github.com/gregsaun/bear_extruder_and_x_axis/tree/master/manual)
## 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](https://github.com/gregsaun/bear_extruder_and_x_axis/tree/master/optional_parts)
## 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](https://www.facebook.com/groups/PrusaBearUpgra
