Config help - 1 fan for both hotend and part cooling

[Perd_Hapley]

#Annex K3 Derivative
#Octopus Pro

I have an interesting hardware setup and could use some help with the config.

Background:
I designed a custom toolhead where the part cooling fan is ducted across the coldend and then piped down to the nozzle. Why? Because I’m bored and I wanted to reduce the weight of the toolhead as much as possible.

Problem:

• Check that whenever hotend Temp is above 50C the fan needs to be running at a minimum of 30% speed
• The fan should be controllable via M106 so that the slicer can still control the part cooling speed during a print

So far I have this simple macro which kicks on M106 when ever M104 is called but it’s not a very robust solution. For instance, whenever a print ends the hotend will still be hot but the fan won’t be running anymore.

[gcode_macro M104]
rename_existing: M104.1
gcode:
  M104.1 {rawparams}
  M106 S77

[EddyMI3D]

A complete klippy.log would be quite helpful.

For a better understanding, you may exactly name the fan you are referring to.
Just fan is quite vague.

@Perd_Hapley

Check that whenever hotend Temp is above 50C the fan needs to be running at a minimum of 30% speed

You set this with

https://www.klipper3d.org/Config_Reference.html#heater_fan

so 100% includes the minimum of 30%

You can’t control the heater fan by M106. It is supposed to run always when a certain temperature is reached (usually 50°C) to prevent clogging.

M106 works on the part cooling fan.

---

Edit: Sorry, misread the title.

[mykepredko]

Could you fill out the information that was indicated as required when you started this post? Without a klippy.log you won’t get any kind of helpful response (just more like this one asking for your klippy.log.

[hcet14]

@Perd_Hapley

I designed a custom toolhead where the part cooling fan is ducted across the coldend and then piped down to the nozzle.

Would you share a picture of that? I’m curious.

[jakep_82]

This could be accomplished with a delayed gcode that runs constantly to check the hotend temp, but I don’t think this is a good idea. You’re going to be fighting a never ending battle between using enough fan to prevent jamming, but not so much that bed adhesion is a problem.

[Perd_Hapley]

I’m still in the process of setting up the printer so there isn’t a klippy log yet. What value it would provide in this case?

[Perd_Hapley]

The toolhead has three purposes.

1. hold the hotend
2. direct air flow
3. hold the z probe (the one quality of life feature I added to the toolhead)

The printer is already build so there’s no turning back now. My barebones macro functions and I’ll use it if I have to but I’d love some help writing something more robust.

I built this printer solely for speed benchies and I’ve clogged enough dragons that I can unclog a heatbreak in a matter of minutes. If I need to print something I’ll just use one of my other printers.

[mykepredko]

If you’ve connected the main controller and running macros then you should have a klippy.log.

The klippy.log provides a running narrative, or “log” if you will, of what’s happening in the printer.

It’s very valuable for the people who are offering to help you. As a good, general rule of life, if people are offering to help you, give them what they feel they need to help you.

[Perd_Hapley]

I tested the macro on another printer.

But I did get the k3 flashed and fired up tonight. The rest of the config appears to be working,so I’ve attached a klippy.log

I did not intended to come across as ungrateful I just didn’t understand why it would be useful. My understanding was that klippy.log was only needed for diagnostic purposes.

klippy.zip (522.9 KB)

[mykepredko]

I was asking because there would probably be clues as to what is happening when the macros executed.

Glad to hear you’ve got things working!

[hcet14]

Which fan are you talking about? Thanks for the pictures, but I can’t recognize the fan on your pictures.

[Sineos]

It is a CPAP blower, you can see it in the back of the picture.

[Perd_Hapley]

As Sineos said, it’s a CPAP blower. Remote mounted, I’ve sketched the ducting to make it more clear how this works

[Perd_Hapley]

My simple macro to modify M104 works well enough when paired with the appriopriate GCODE start and end code.

The only issues is when I set the hotend temp through the mainsail interface instead of issuing M104 it issues

SET_HEATER_TEMPERATURE HEATER=extruder TARGET=235

Any ideas on how to modify this command to send M106 at the same time? or send my modified M104 macro instead?

[Perd_Hapley]

Bump. Still looking for ideas

[EddyMI3D]

Honestly, I would abandon this idea.

For the heat break you need cooling as much as possible, else cloggings are pre-programmed due to heat creep.

[Perd_Hapley]

No worries. Heat break clogging isn’t an issue for me.

If you could help me solve the actual problem in this thread then I would very appreciative.

[Sineos]

The only solution that exists you already mentioned in your first post

@Perd_Hapley

For instance, whenever a print ends the hotend will still be hot but the fan won’t be running anymore.

[gcode_macro M104]
rename_existing: M104.1
gcode:
  M104.1 {rawparams}
  M106 S77

As for the mentioned issue, just define a PRINT_END macro that does the needful and call it from your slicer as ending gcode.