[Feature Request] Support for multiple fans for IDEX extruders

[Don-Swanson]

Version

2.1.0

Operating system type + version

Fedora 31

3D printer brand / version + firmware version (if known)

Formbot T-Rex 3

Behavior

The Formbot T-Rex3 Is a dual-IDEX printer with a separate controller for the fan on each print head. Currently, when printing with both extruders, the fan is never enabled for the 2nd print head. The fan speed is always attributed to the 1st print head.

[BeatSlayer]

Can you turn it on by manually sending the Gcode? Does it stay on when toolchanging? Could be a firmware bug.

[Don-Swanson]

It's not a firmware bug. PrusaSlicer doesn't generate the necessary Gcode for a secondary fan. It only generates code as if there is only one fan.

In all of my Gcode produced by PrusaSlicer it is M106 S. IE: M106 255

In order to control the speed of the second fan there needs to be a P in the command too M106 P S. IE: M106 P1 S255

Same thing with turning the fans off, you need M107 P

If I manually send the commands to the printer via octoprint terminal, everything works as expected. The issue is that PrusaSlicer doesn't seem to have an option to account for multiple fans

[Don-Swanson]

any update, or any "cheat code" that I could use to make this happen?

[pkucmus]

I'm interested as well. On a Duet (RRF) when you setup different fans as "fan1" and "fan2" you need to do M106 P1 Sxxx and M106 P2 Sxxx to control the fans properly.

[Kachidoki2807]

Any news on this topic? I am currently building an i3 based IDEX machine, but indeed the FANs are not properly handled by PrusaSlicer.

Maybe someone has an idea to workaround this, using the custom G-Code sections and some magic placeholders (I wasn't able to find an appropriate one)?

[Don-Swanson]

As a temporary "workaround" I just add the following to my Start G-Code: M106 P1 S200

Granted it's a static temperature for the whole print, but it's better than nothing. (Especially when you do a lot of remote printing.

[Don-Swanson]

I've also read that you can change the firmware to control both fans as one in the same, so if you're building your own, that may be an option until they have software allowing the control of 2 seperate fans

[pkucmus]

That may not be a bad idea, in the "Tool change G-code" we could do something like:

{if layer_num == 3}  ; to start cooling after 2 layer
{if next_extruder == 0}
M106 P0 S1.0
M106 P1 S0
{elif next_extruder == 1}
M106 P0 S0
M106 P1 S1.0
{endif}
{endif}

And disable fan control in the filament settings.

[ogland]

I very much want this too.

[Kachidoki2807]

Hi, I have now my MakerFr i3-RDX built in alpha revision (IDEX printer). I am currently tuning the slicer profile, but I am still stuck on the FAN speed that is not properly handled by PrusaSlicer, and apparently neither by Slic3r: https://github.com/slic3r/Slic3r/issues/4694

I found also this related topic: https://github.com/prusa3d/PrusaSlicer/issues/3583

Generally speaking, the M106 handling should be reworked to fulfill at least the [P] parameter. If it imply too much impact into the current implementation, PrusaSlicer could provide at least something like a "current_extruder_fan_speed" placeholder to be able to handle it from the toolchange custom G-Code.

[ogland]

What I found is that with fanmux, the fan targeted with M106 without the P should be current extruder, but with T parameter in toolchange gcode, the M106 command fires BEFORE the toolchange and possibly only when the fan speed should change. If instead the fan speed could be set after toolchange gcode and always to the correct current speed I believe it would work good.

Also an idle fan speed is good to have with ooze stoppers and that would be very easy to enable with a tool change gcode in that case.

[Kachidoki2807]

Hello,

I digged a bit into the code (it is very new to me, I am not used with the Prusa workflow). I found that there is potentially an inversion like mentioned by @ogland. https://github.com/prusa3d/PrusaSlicer/blob/9fdf8c8b8d46e26968baa5d6e6b80bfcea046e0c/src/libslic3r/GCode/CoolingBuffer.cpp#L735-L741 My guess is that the line 741 should be before the if statement (move to 737) to place the M106 after the Tx because it is the fan speed of the new extruder that should be applied here.

I built and tested this small fix with success.

[andrewseago]

Any update on this? I'm super interested in it. One way could be to add a setting per extruder for the parts fan number.

[Don-Swanson]

@schuessm The problem is that modern more advanced idex printers now allow you to control the fan speed per head. Say for instance you are printing with something on head one that needs 100% fan, but the other head needs 0% fan.

So no, it's not a firmware thing (at least not with marlin), it's a thing that should be controlled by the slicer depending on the material/active head.

[schuessm]

oh, sorry than I missunterstood the problem. But did Prusa work for you with IDEX? I had problems with temperature. The second extruder does not head up in my modell. the setup of filament, profile is correct

[Don-Swanson]

PrusaSlicer works for Idex in general. I found you have to preheat both heads before starting the print, but I always preheat anyway, so it never really was a a problem for me.

But the problem in this issue is for different fan speeds per head.

[schuessm]

How did you realize the prehead function? I didn't found a function? Which version of Prusa are you using

[Don-Swanson]

I would request that you please stop muddying this issue thread with your general questions or unrelated issues.

The purpose of Github issues is to work on a specific bug or issue at hand and a new issue can be opened for unrelated issues. For general questions I recommend the Prusa Forum.

[bubnikv]

@We at PrusaResearch did not manufacture IDEX or tool changer machines before. Now with the introduction of the tool changer Prusa XL printer, we are actively looking into the IDEX / tool changer requirements.

The topic we are looking into is how much of the tool changer support we shall put into firmware vs. into slicer generated tool change G-code blocks. If we decide to put the functionality into the firmware, then our printer will be happy with just a single virtual cooling fan being supported by PrusaSlicer, however I understand that that may not fit your current firmware. On our newer machines we use the stock Marlin.

BTW what firmware are you running? I suppose Marlin and RepRapFirmware on Wifi Duet, right?

[themacboy]

I had the same problem. I'm managing it using macro script in Klipper... but that's not the best solution. It would be great if PS you could manage more than one tool head with a separate fan.

Thanks in advance.

[Elevatea]

Just to add a possible solution, I have used the Post Processing Scripts from PS to automatically modify the gcode while saving it, to call a script that adds a second line that turns on the second fan every time it founds a M106 S255 (for the first fan).

It's the python script below, all what you have to do is to save it as a python file, and then put the path to it with the "python" or "python3" command in the Post Processing Scripts.

import sys

def modify_gcode(input_file):
    # Open the input file and read all lines into a list
    with open(input_file, 'r') as f:
        lines = f.readlines()

    # Open the input file again in write mode, this time we will overwrite it
    with open(input_file, 'w') as f:
        # Iterate over all lines in the file
        for line in lines:
            # If the line is the fan control command for the first fan
            if line.strip() == "M106 S255":
                # Write the fan control command for the first and second fan each on a new line
                f.write("M106 S255\nM106 P2 S255\n")
            else:
                # If this line is not a fan control command, write it back to the file as is
                f.write(line) 

# Call the function with the name of the file PrusaSlicer passed to the script
modify_gcode(sys.argv[1])

To use this script, save it to a modify_fans.py file on your system. Then, in PrusaSlicer, go to Print Settings -> Output options -> Post-processing scripts and enter the path to the script, preceded by the command to run a Python script, which is typically either "python" or "python3". The exact command and path will depend on your specific system setup. For example, it might look like this: python3 /path/to/your/script/modify_fans.py.

[Calypsoblur]

I have updated the current (2.6.1) code to add the P in the fan speed setting and the current extruder, and it is working great on my Snapmaker J1S. Have not added to M107. The code is only for Marlin or similar gcode flavor, which should include RepRap and Klipper, but as stated in first sentence, not tested. This will require you to compile your own version. Include my files at your own risk. I have added "by CRobson" on all lines I modified. PrusaSlicer/src/libslic3r/GCode.cpp PrusaSlicer/src/libslic3r/GCodeWriter.cpp PrusaSlicer/src/libslic3r/GCodeWriter.hpp PrusaSlicer/src/libslic3r/GCode/CoolingBuffer.cpp PrusaSlicer/src/libslic3r/GCode/CoolingBuffer.hpp I don't remember making any changes to CoolingBuffer.hpp, and I can't see anything I may have changed, but I did mark it as updated...

you can download from my github Multi-Extruder Fan handling

[Drizzt321]

I'm finding this is an issue with the FormBot Marathon IDEX as well. When switching tool heads, PrusaSlicer doesn't have the Part Fan for either tool head turn on.

Under Filament Settings -> Cooling, I have Keep fan always on checked. This is PrusaSlicer 2.7.2, PLA.

I haven't tried the script from @Elevatea yet, just found this ticket and wanted to chime in that this is very much needed.

[YILI245]

I'm finding this is an issue with the FormBot Marathon IDEX as well. When switching tool heads, PrusaSlicer doesn't have the Part Fan for either tool head turn on.

Under Filament Settings -> Cooling, I have Keep fan always on checked. This is PrusaSlicer 2.7.2, PLA.

I haven't tried the script from @Elevatea yet, just found this ticket and wanted to chime in that this is very much needed.

Hi, I have the same problem in my Marathon. Try to remove following code in after layer change: {ifcurrent_extruder==0} SET_FANSPEEDFAN=Tool_1_partfanSPEED=O.O {else} SET_FANSPEEDFAN=Tool_0_partfanSPEED=O.O {endif}

And add following to the Tool change: {if layer_num>=disable_fan_first_layers[0]} {if current_extruder==0} SET_FAN_SPEED FAN=Tool_0_partfan SPEED=0.0 ; 关闭0号挤出头的风扇 SET_FAN_SPEED FAN=Tool_1_partfan SPEED=1.0 ; 开启1号挤出头的风扇 {else} SET_FAN_SPEED FAN=Tool_1_partfan SPEED=0.0 ; 关闭1号挤出头的风扇 SET_FAN_SPEED FAN=Tool_0_partfan SPEED=1.0 ; 开启0号挤出头的风扇 {endif} {else} {endif}