hhy5277 / prusa_i3_bear_upgrade

Stronger frame for Prusa i3 MK2(s), MK2.5 and MK3

Prusa i3 Bear Upgrade V2.0

Introduction

This is an aluminum frame conversion for the Prusa i3 MK2, MK2s, MK2.5 and MK3.

Josef PRŮŠA has created numerous of incredible 3D printers and its latest Prusa i3 MK3 is capable of very impressive print quality for a very low price. A huge thanks to him and all its team!

One of the down point of the Prusa i3 MK2 and MK3 is the rigidity of the frame. A very good project has solved those problems by using 3030 extrusion aluminum : Prusa 3030 Haribo Edition. So why another conversion build? Check the next section ;)

Why another conversion build?

Here are the features that explain why I decided to create another printer upgrade.

• Use as much as possible original parts (no need to print a new RAMBo cover nor change any cable, rods or firmware)
• Compatible with MK2, MK2s MK2.5 and MK3
• Let user choose between two versions :
  • Half upgrade : similar to MK3 and cheaper
  • Full upgrade : stronger but more expensive
• Highly detailed manual
• Use more aluminum and less printed parts (3D printed parts can crack and are less reliable)
• Use Openbuilds hardware :
  • Single platform of multitude compatible hardware parts
  • V-Slot offers more possibilities for printed parts and customisation than T-Slot
  • Open source with powerful community
  • Easy to square and build
  • Worldwide shipping plus several other shops selling these parts
• Other type of aluminum extrusions can be supported thanks to parametric design (check Fusion 360 files)
• 3D printed parts designed using advanced techniques like selective infill, clean vertical holes, sharp angle...
• Open source by providing STL, STEP and Autodesk Fusion 360 files

WARNING: Full Upgrade MK2S, MK2.5 and MK2.5S

We are currently working on reducing the number of versions of the Full Upgrade kit. MK2S, MK2.5, MK2.5S will be merged to MK3 frame. Most of the official distributors are already selling only MK3 frame.

How to build MK2S, MK2.5 or MK2.5S on MK3 frame

1. Use this Y belt adapter: https://www.thingiverse.com/thing:3468567
2. You will need a new Y belt because MK3 frame is slightly longer. Will be a good opportunity to refresh your old belt. Here is the reference to use with the belt: GATES LL-2GT RF 6mm Width 2mm Pitch 660mm long. Belt From Prusa store works perfectly as well.
3. Use all MK2S/MK2.5(S) parts except Y rod holders and build helper.
4. You need to use the 106mm build helper

Full And Half upgrades

The Prusa i3 Bear upgrade is proposed in two versions: full or half upgrade.

• Half upgrade : upgrade your MK2/MK2s/MK2.5 frame to MK3 type
• Full upgrade : has a redesigned and stronger Z axis for all MK2 and MK3 printers but is more expensive

   

Here is a comparison table to help you choose :

	Half Upgrade	Full Upgrade
Compatibility	MK2, MK2s and MK2.5	MK2, MK2s, MK2.5 and MK3
Y axis rigidity	♥️ ♥️ ♥️ ♥️ ♥️	♥️ ♥️ ♥️ ♥️ ♥️
Z axis rigidity	♥️ ♥️ ♥️	♥️ ♥️ ♥️ ♥️ ♥️
Noise level	♥️ ♥️ ♥️ ♥️	♥️ ♥️ ♥️ ♥️
Customisation	♥️ ♥️ ♥️	♥️ ♥️ ♥️ ♥️ ♥️
Material cost	💰	💰 💰
Number of V-Slots to cut	6 (4 different lengths)	7 (4 different lengths)
Number of V-Slots to tap	4	0
Can I place the printer inside an enclosure and PSU outside?	❌ PSU rigidify the Z frame	✔️
Capability to increase Z axis height? (need customisation)	❌	✔️

Half upgrade use the same v-slots and printed part for MK2(s) and MK2.5. However, the full upgrade has 3 different versions, one for MK2(s), one for MK2.5 and another one for MK3. You can discover the difference in the full upgrade page.

Several printed parts are shared between all these versions. This makes easier to move from half to full upgrade, or full upgrade MK2 to full upgrade MK3.

Go to HALF upgrade page or FULL upgrade page.

Where can I purchase the hardware?

Official distributors

Official distributors are selling a kit with all screws and extrusions ready for the upgrade, you will only need to print latest 3D printed parts.

All distributors are following specifications to ensure you will have a perfectly squared Bear. All distributors are using professional machines dedicated to cut aluminum extrusion (like CNC machines). In case your extrusion is out of specifications, you can get a replacement for free. We have created a dedicated support channel in case customers have more technical questions or need information for a custom build.

• 
  All3D Makers (US)
  all3dmakers.com

• 
  Blackfrog (EU)
  blackfrog.pl

• 
  Lecktor (EU)
  lecktor.com

• 
  Makerparts.ca (CA)
  makerparts.ca

• 
  Ooznest (EU)
  ooznest.co.uk

• 
  RatRig (EU)
  www.ratrig.com

By purchasing a kit from official distributors you are supporting the development of the Bear project, thank you very much!

Openbuilds distributors

You can also purchase parts separately worldwide. Checkout my list of distributors here : Openbuilds stores list

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

Optional parts

Checkout the best optional parts for you Bear : Optional Parts

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/gregsaun
• A tip via Paypal: paypal.me/gregsaun
• A tip via Thingiverse: thingiverse.com/pekcitron

Big thank you in advance ❤️

Thank you

Thank you to all my Patreon : 3DPrintronics, Ahmed, Albe Gouws, Anders Svendsen, Apton Ika, Arnaud CHRISTEL, Bearpaw93, Christopher Lee, Christos Goulas, Corey Dryja, Cristian Toma, Daniele Malinconi, Darren Furniss, David Pesce, Doug Palmer, Erich Jermann, Espen Fjellvær Olsen, Evan, flobler, Grigori Palamartšuk, Hector Gonzalez, Jason Marcus, Jimmy Lee, Joan Torner Corrons, Joel Weinberg, Jonathan Ryer, Josh Carter, Joshua Jones, Jotham B, JTa, Kevin Smith, mark leino, Matthew Humphrey, Miguel Castillo, Mike Phelps, Nathan Trop, Orlando E Moran, Patch Best, Peter Boardman, Pierre Allegraud, QcRetro, ra100, RC-CnC, Richard Bateman, Riot, Ryan Lobbins, SamE0717, Schwiizer, Scott Rini, sleene, Stanislav Kljuhhin, Stephan Kohls, Steven Clark, Steven Daglish, Ted Rathkopf, Tomáš Vydra, Total Dramatist, Tree of Broken Hearts, Tyler Townes

Thank you to all that have send me a tip on Thingiverse and PayPal.

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

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

Thank you to all official distributors for taking care of the kits and customers.

Thank you Jason from LDO Motors for the quality manufacturing and relationship.

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

Thank you for making the community alibe with all your comments, issues, pull requests, optional parts, make, pictures, etc.

Thank you to David Ogles, Flobler, Jason from LDO Motors, Matthew Humphrey, Nathan Denkin, Orlando from All3DMakers, Sleene, Termlimit, Vertigo295 for helping me developing the Bear project.

Sources

Here are a list of sources I used to build this project :

• Prusa : http://www.prusa3d.com
• Prusa 3030 Haribo Edition : https://github.com/PrusaMK2Users/3030_Haribo_Edition
• Openbuilds : https://www.openbuilds.org
• Prusa i3 Solidworks parts from jzkmath : https://github.com/jzkmath/Original-Prusa-i3/

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