Easy and automatic nozzle cleaning for an Ender 3 Pro with an inexpensive brush.
PETG is quite stringy and having strings of filament on your first layer is quite annoying. To avoid babysitting each print, I looked at a couple of designs on thingiverse but none really worked well for an Ender 3 Pro.
- Cheap brass brush - in this design I used a sub-1$ one from Harbor Freight
- 2 or 3 M1.7 screws (or equivalent very small and short screws)
- T-Nut (you can 3d print this M3 Tnut )
- Brush support
- 3d print brush support (both STL and Fusion360 files are provided)
- 3d print Tnuts (or buy/reuse other ones)
- Cut away the brush handle: keep the part where the brass brush is
- Extend limits of your printer: in my case I found that I can safely extend X to 248 mm
- Write a sequence of Gcode commands that moves the head back and forth (see examples at nozzle_clean.gcode and g12_macro_klipper.cfg )
In action:
A good option is to define the cleaning code as G12 and use a macro in klipper. See code at g12_macro_klipper.cfg
The support it works best when the display is removed. If the display is not removed, you need to offset Z commands upwards in the examples provided.
I use Klipper and I simply modified the printer.cfg file to account for a larger X dimension
[stepper_x]
#...
position_endstop: 0
position_max: 248
Do not modify your slicer, it might think there is more bed than there is