Creality Space Pi X4 and X4L Auto Rewinder Mod

This project is meant to replace the buffer unit for the mmu3 by rewinding filament instead.

The printed parts for this are as follows(I printed all the parts in PETG, no supports needed):

Alternatively, the parts contained in the All files have been Separated out as follows:

Non-Printed Parts:

Creality Space Pi X4 - https://www.creality.com/products/creality-spacepi-x4?spm=..page_12186981.nav_link_store_1.1

(16) M3x10 screws

(8) 608 bearings

Assembly Instructions:

1) Prep your Creality Space Pi X4 by removing the spool holders that it comes with. The New Spool Holders will be inserted where these are. 

As a note: This turned out to be the most difficult step for me, and required some prying to remove these. I am not responsible for any damage that occurs to your creality space pi x4 for this step or any others. Please take care when removing these.

2) Assemble the spool holders:

For each of the 4 spool holders, you will need:

1 - Side Bracket

1 - Middle Bracket

2 - Crossbeam 

4 - m3x10mm screws

An m3 allen key or screwdriver (depending on which type of m3x10mm screws you are using)

Start by screwing in the Crossbeams one side at a time. The hole is larger on one side of the side bracket than the other, that side will be the side you screw in from so that the screw head does not stick out once fully screwed into place.

Finish screwing in the other side so that the crossbeams are tight to the side brackets:

Push the Side Brackets into the former bearing holders, one corner at a time. This required moderate force. Please take care not to push too hard and damage the Space Pi x4, as your tolerances may be different from mine for my 3d printer. If it seems to be requiring a significant amount of force or not going in, you may need to sand down the parts before inserting.

Here is how mine looks after inserting into the bearing slots:

3) Assemble the Auto Rewind Spools.

You will need the following for each of the 4 spools:

1 - Cylinder - Hexagon OR Cylinder - Diamond

1 - Cylinder - Top

1 - Axle

1 - Spring - Top

1 - Spring - Bottom

4 - Spring - Middle 1

3 - Spring - Middle 2

2 - 608 bearings

Insert the 608 bearings into both Cylinder parts:

The version from VincentGroenhuis, linked here:
https://www.thingiverse.com/thing:3781815
Has pictures that show how the spring goes together.

Note that the Remixed version has more of a ‘Gear’ for the bottom most spring than the version shown in the picture. 

The order of assembly from bottom to top is:
Bottom → Middle 1 → Middle 2 → Middle 1 → Middle 2 → Middle 1 → Middle 2 → Middle 1 → Top

Once the spring is constructed, Put the Diamond or Hexagon Cylinder all the way onto it so that the gear interacts the gear cutouts in the Cylinder part.

Then screw on the Top Cylinder part(Take care to note the orientation of the middle of the Top Spring! It is important for inserting the axle!)

Finally, insert the axle all the way through the spring and throught the bearing.

If you enjoyed this project, please consider buying me a coffee

Cheers!

Change Log:

v1.1 - changed from 2 side brackets for the spool holders to 1 side bracket and 1 middle bracket to account for small plastic piece on bearing holder that causes spool holder to not quite sit flush.

Test folder added with metal spring version. Metal springs harvested from these mini retractable tape measurers: https://www.amazon.com/dp/B0BWHDBM1K?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
Note: this model is in testing phase and may have changes made. I have not put together a guide for assembly on this one yet. Please let me know if you are testing this model and any feedback or questions you have on it.
There are 3 key new features for this new version: Metal springs, Ratchet for when spring gets tight, and Diameter Expanders for different sized spools.