[FR] periodic nozzle auto clean

[Andrei-Pozolotin]

Description

Marlin already implements G12 nozzle clean command
http://marlinfw.org/docs/gcode/G012.html

Some high end 3d printers do periodic nozzle auto clean
by automatically executing an equivalent of G12 every few layers.

Is it feasible to introduce similar feature in Marlin?
Where in Marlin code one would start to implement this?

[reloxx13]

could be doable with postprocessing script which inserts g12 every x layers.
but i dunno if u can execute g12 mid printing in the gcode file.

if u want to try it, u can use this as start and replace the temp logic with the nozzle clean.
should not be too hard to modify
https://github.com/fchorney/CuraPlugins/blob/master/post_processing_scripts/VaryTempWithHeight.py

[Andrei-Pozolotin]

thank you for the cura plugin link, I am still interested in firmware-level solution

[boelle]

insert it in start or stop Gcode of the slicer, how would firmware know when to do it?

personal i take a single sheet of toilet paper and fold it to form a small pad
then every 2nd print i carefully wipe the nozzle while its still semi hot (~150C) and it takes off all the molten filament without scratching the nozzle

[boelle]

Some high end 3d printers do periodic nozzle auto clean
by automatically executing an equivalent of G12 every few layers.

what you dont know is how they did it, my bet is that they have it setup in slicer

with slic3r you can insert this in layer change code

{if layer_z ==5.00}M104 S200; change temp to 200C at layer height of 5.00mm{endif}

does not take much rocket science to change that to wipe the nozzle every 5 or 10 mm

[Andrei-Pozolotin]

thank you for the input. do you by chance know a "safe place" in marlin source
to inject auto-clean hook code w/o messing up the rest of the system (planner, motion advance, etc)?

[boelle]

you dont have to put in in the firmware

just trigger the clean from slicer like i suggested?

[dcwalmsley]

So I'm a bit of a NOOB when it comes to writing scripts but I am in agreement that I would like to implement G12 every so many layers (operator's choice) or after so many minutes throughout the print. In other words repeat cleaning process periodically while print is running to ensure clean nozzle and no residual or build up on nozzle tip that can blemish the print. This does not replace dialing in the temperature, feed rate, retraction distance and speed, but to help mitigate print failures.

I'd appreciate either an option to include this into firmware or some way to develop this into GCODE for slicing.

Thanks,
Doug W

[vajonam]

If you are running Prusa Slicer or Super Slicer you can add this

{if (layer_num != 0)}{if (layer_num % 40) == 0}G12 P1 S2{endif}{endif} simple mod function to do a G12 Wipe every 40 layers. skipping the first or 0th layer.

quick explanation.

layer_num - Slicer's variables that is available for custom GCode
40 - clean ever 40th layer.
G12 - Nozzle Clean - https://marlinfw.org/docs/gcode/G012.html
P1 - Triangles
S2 - Two Strokes

You can change that however often you like. This is assuming you have G12 in the start g-code, which does a more thorough wipe, this particular is just a quick wipe of S2 two strokes

Here is Pursa/Super Slicer example, but others will have similar places where you can enter it in.

EDIT: Make sure the print you are doing isn't knocked over the X-Gantry this depends on brush position.