Prusa MINI Linear Rails MGN12 - Y Axis

This is a remix of the Prusa MINI Y Axis Linear Rails Mod by Ryper3D that I re-created from scratch from the original Prusa MINI Printable Parts with the following differences:

• Clean and pleasant aesthetic. No personal logos, crazy lines, and colors. Enjoy an aesthetic that looks like it could be a stock part.
• Multiple front plate designs. Whether you like it plain, with hexagons, with Prusa Mini logo, or with functional attachment options for cameras and lighting, there is a version for you.
• Multiple rear plate options. Two versions with and without attachment grid for accessories.
• Higher clearances for the MGN12 rail mounting hole positions to account for cutting inaccuracies.
• STEP files available for easy remixing, including a model of the full assembly for reference.
• Elaborate documentation and detailed step-by-step assembly instructions. 
  A lot of effort went into making this project accessible with a lot of up-front questions answered, detailed parts list with tested sourcing links, and illustrated instructions that cover every single step of disassembling the Y-axis and re-assembling it with linear rails.

FAQ

• Does this work with the MINI+?
  Yes. But you have to print an older version of the Display Box (or this one with USB) because the injection molded front plate of the MINI+ uses a different display mount.
  Alternatively, you can use @Waschtl's Front Plate Remix that works with the injection molded display box.
   
• Is it better than stock? 
  I have noticed that the Y movements are a noticeably quieter and it overall feels much sturdier. The crazy noises that the printer can make during faster diagonal moves are gone, based on my experience. Multiple people have commented in their Makes that this mod made their printers quieter.
  There is no quantitative data on this and the observations are entirely subjective.
   
• Will this affect Input Shaping?
  Theoretically, yes. However, I've been using Input Shaping with this printer since the feature was released and have had no negative experiences. 
   
• Does it pass the XYZ self test?
  Yes. It passes the full self test.
   
• Is this compatible with the Prusa Mini Base by David Warboss?
  Yes! Check out this Make by Tobi3107.
   
• Is this compatible with my Z-axis stabilizer brace?
  Maybe not as it might interfere with the MGN12C blocks. However, you can use this Z-axis brace that is compatible and tested. Scroll all the way down to the “Compatibility with Other Mods” section for more info on which mods may or may not be compatible.
   
• Can I use MGN12H blocks instead?
  You can use an MGN12H block for the right rail. The two blocks on the left rail must be MGN12C in order to ensure the right amount of Y travel

Bill of Materials

All sourcing links have been tested by myself.

Linear Rail Specs

The rails should have a total length of 280mm and a hole spacing of 25mm. The rail must be symmetrical so that the distance from the last hole to the end is equal on both sides. Up to 2mm cutting error is still okay.

If you have difficulty sourcing a 280mm rail can buy a 300mm rail, which should be easier to source, and cut 10mm off each end with a Dremel cut-off wheel or other suitable tool.

Printed Parts

Front Plate Versions

Choose a front plate based on your preferences. The “Fannypack” versions have a 20x20mm grid using M3 threads (use heat-set inserts, see BOM) to attach accessories such as webcams, lighting, etc. You will have to design your own accessories or adapters.

Rear Plate Versions

Choose between a plain rear plate or one with a “Backpack”. The “Backpack” version has a 20x20mm grid (same as “Fannypack” font plate) with M3 threads (use heat-set inserts, see BOM) to mount accessories to the back of the printer, such as buck converters, relays, etc. You will have to design your own accessories or adapters.

Printing

Recommended Settings

• 0.4mm nozzle
• 4 or more perimeters
• 0.4mm extrusion width (0.45 should work too bit not tested)
• 30 to 40% infill
• 5 top and 5 bottom solid layers
• PETG or better

Part Orientation

All STL files are pre-rotated to the correct orientation for printing.

Assembly Guide

Preparation (important!)

• Install the 2nd MGN12C Block on one of the rails.
  If you have one rail with an MGN12H block, make sure to install the 2nd MGN12C block on the rail with the MGN12C block. Carefully transfer the block from its storage carrier rail onto the rail without losing any of the ball bearings.
   
• Clean and re-grease the linear rail blocks and guide rails. 
  There are various video resources online on how to do this. You must flush out any factory debris and storage grease using solvents and then re-lubricate. This is best done with the blocks installed on the rails to avoid losing any ball bearings.
   
• Inspect your parts and make sure they look great and aren't warped. 
  Do not use warped parts as it may cause misalignment of the rails. Reprint if necessary.
   
• Test if the MGN12 rails fit all the way in to the plates. 
  If you have printed the Fit Test then they should fit just fine. If not, check your parts for warped corners again. If they are not warped you can use a file to widen the opening just enough so the rails can be inserted all the way.
   
• Insert an M3 Nyloc nut into the Y Front Plate where the display will be attached. 
  This can't be done after assembly so do this first.
   
• Install heat-set inserts.
  If you use any of the “Backpack” or “Fannypack” versions of the font or rear plates, insert all the heat-set inserts. This is easier to do now than after the assembly.

Disassemble The Stock Y-Axis

Re-Assemble the Y-Axis with Linear Rails

Compatibility with Other Mods

To figure whether a mod will be compatible you must understand the dimensional changes.

The overall dimensions of the font and back plates are unchanged. However, the MGN12C blocks and rails are wider than the smooth rods and bearings. For this reason the belt path had to be moved 3.53mm to the left so that the block doesn't collide with the motor.

Mods that attach to the Y-axis extrusions should give about 1mm of clearance on the sides and bottom of the MGN12C blocks.

On the left, the MGN12C block protrudes 3.5mm beyond the Y plates.

Potentially Incompatible Mods

• Mods that are mounted to the top of the Y aluminum extrusions, such as some Z-axis stabilizers. These must potentially be changed to clear the path of the MGN12C blocks.
• Alternative belt tensioners
• Alternative belt holders

Remix Sources

• Prusa MINI upgrade hiwin Linear rails (Y mod) MGN12 by Ryper3D (Creative Commons 4.0 International
  Attribution-NonCommercial)

This remix source is listed independently because it is mis-licensed (actual license is GNU GPL v3) and this project can not be saved under the correct license because the remix source's license is incompatible with the correct license.