Introducing an auto-rotation mod for the Sunlu S4 filament dryer. 

I made this mod for various reasons. One reason is that this has not been previously done. Secondly, on the drying phase, not only will the spool be spinning, which allows for an even drying result, but it will also speed up the drying process considerably.

Seven of these parts are 3D printed. You will need to make three physical cuts into your Sunlu dryer: Two for the gears to pass through and one for the switch.

This modification uses the 12V power system of the dryer with the addition of a DC-DC Buck Converter, we are changing the voltage from the original ~12V to now approx ~3-4V. The Lower the voltage, the quieter and slow it'll spin. 

1. Is to keep the gears in 
2. Is to reduce the RPM to a controlled speed, allowing for slow consistent rotation to be used during filament drying.

Filament used to print this is ASA (Link below), i chose this so it wont deform during operation.

• Instructions: 

This project involves working with high-voltage components (120-240V). If you are not comfortable or experienced with this, please do not proceed. Before you begin, make sure to unplug the device from the wall. This is crucial before you start cutting, soldering, or touching any internal components.

• 5 Print files (Total Print Time ~ 4H 33Min - 56.5 g Filament)
  • Main Body
  • Axels (Left, Right)
  • Support Bridge
  • Spur Gears (1x Main roller, 2x Axel Gears
  • Buck Converter Box (Optional)

• Items Needed
  • Soldering Iron
  • Solder
  • Soldering Flux/Paste
  • Switch (Rocker, Push Button)
  • M3 or M2 screw
  • 20-AWG Electrical Wire

• File Type (Included) - (STL files are saved in High Mesh Resolutions, that's why file sizes are larger than normal)
  • STEP
  • STL 
  • 3MF (Bambu Studio) - I have the files orientated with proper support requirements

How-To Video 

All the Amazon links below are affiliate links. While I'm not asking for donations on this project, but using these links for any of your purchases is a wonderful way to support my work at no cost to you. Thank you so much for your support!

LM2596 DC-DC Buck Converter

[https://amzn.to/4lpaCVJ](https://amzn.to/4lpaCVJ)

Gearbox Motor

[https://amzn.to/4fC7LYc](https://amzn.to/4fC7LYc)

Polymaker ASA

[https://amzn.to/4mLT6ML](https://amzn.to/4mLT6ML)

Push Button (This switch can be interchanged with whatever you like)

[https://amzn.to/4oKPBb5](https://amzn.to/4oKPBb5) (This is the one i used)

[https://amzn.to/4oM37uX](https://amzn.to/4oM37uX)

[https://amzn.to/45H5uXr](https://amzn.to/45H5uXr)

20-AWG Electrical Wrie

[https://amzn.to/41fM6iQ](https://amzn.to/41fM6iQ)

Heat Shrink Solder Seal Wire

[https://amzn.to/3UGJKps](https://amzn.to/3UGJKps)