Anycubic Chiron Direct Drive conversion (BMG Mirrored, SKR V1.4 Turbo)

 Update 18/07/2024 

• Added remixed bracket for attaching the cable chain and filament sensor
  • I now use a reverse bowden to the printhead and a feedtube from the filament to the sensor
  • They are both attached using PC4-M6 pneumatic fittings
• Filament Sensor is now enabled again
• Updated firmware to fix bugs with BLTouch. Now the BLTouch should no longer falsely trigger when probing. Probing is now considerably slower but I create my mesh and then just tilt it in my Start-GCode

This is the printhead assembly of the Direct Drive conversion I did for my Anycubic Chiron. The parts I'm using:

• Bondtech BMG Mirrored with Bowden adapter and Nema17 Pancake Stepper
• E3D Volcano (also fits regular V6)
• BLTouch V3.1
• BTT SKR V1.4 Turbo with TMC2208 stepper drivers
• BTT TFT43 V3.0

I used this design as a base and modified it to work with the parts I wanted to use. The model was messy to work with in Fusion360 so I also had to use negative volumes in the slicer itself to remove some leftover geometry of the old model. Double-check, that your Carriage_Back file matches the one in the screenshot (regarding negative volumes and the BLTouch spacer). 

I included the Fusion360 file for the Carriage_Back but be aware that there are some errors and non-manifold geometry that I couldn't remove!

This conversion also comes with up-to-date custom firmware for the SKR V1.4 Turbo and includes support for most new Marlin features, most notably:

• Linear Advance
• Input Shaping
• Unified Bed Leveling
• Firmware flashing over OctoPrint

All the code can be found on my Github Repo

Assembly tips:

• The two holes next to the groove mount aren't really precise so I just drilled them out and used threaded inserts.
• I used a bit of hot glue to keep the breakout board in place, although the fit is pretty tight so its probably also fine with just a screw and washer.

Additional prints/upgrades:

2020 Extrusion Dust Covers

BTT TFT43 Case and Mount

Use this case and print the provided TFT43_Mount.3mf and modified TFT43_Back.3mf to conveniently mount the display on the front extrusion of the printer.

BLTouch cable management

I had issues with electrical interference on my BLTouch so I moved the cable away from the main cable chain. To do this I created this clip which lets me mount the cable right on top of my preexisting cable chain.

Dampener Feet

Electronics box mod

I followed these 2 videos: Vid1 & Vid2 to swap the fans of the electronics box with Noctua fans to significantly reduce the noise of the printer. The video is in German but you should be able to follow it nonetheless.

Filament Sensor Holder

This holder allows you to attach a PTFE tube to better feed the filament

SKR V1.4 Turbo Mount

Octoprint

I used this case for the Raspberry Pi and this camera mount. I also created custom support beams which get clamped to the threaded rods of the Z-Axis reinforcement. I also included a cable clip designed to better manage the long ribbon cable coming from the Raspberry Pi Camera.

Powder Coated Spring Steel Bed

I ordered a 410mm x 410mm spring steel bed on AliExpress. If this specific listing isn't available anymore, just make sure it comes with a magnet sheet which you can adhere to the original Ultrabase build surface.

Y-Axis Cable Chain

Y-Axis Motor Stabilizer

Z-Axis Reinforcement

I printed the files by Zoltan3D but I'm unable to find the original Thingiverse page so I uploaded them here as well. They use threaded rods to make the whole frame more rigid. Additionally, I also removed the pockets on the back where the Z-rods are supposed to sit in. Through testing, I found out, that leaving the Z-Axis unconstrained at the top provided better printing results.

Print Settings

Printer Brand:

Prusa

Printer: 

Mini+

Supports: 

Use provided custom supports for Carriage_Back and Fanduct.
Use supports on build plate only for Carriage_Front

Nozzle: 

0.4mm

Resolution:

0.2mm - 3 Perimeters

Infill: 

15% Adaptive Cubic

Filament:
Prusament PETG Prusa Orange