Greetings,
I print mostly from ABS. Lately I’ve noticed that the chamber fan is turned on when printing, but never turns off.
Is there a way to tell BambuSlicer (or OrcaSLicer) to turn the fan some time after the print is completed?
Thank you
chris
Hi
I understood that for ABS filamaent it’s done intentionally to continue filtering air inside the chamber after printing
I know you can activate, deactivate and adjust speed of the chamber/exhaust fan during and also after printing completion from Bambu Studio. But I couldn’t find the way to set the time
I’m also interesting to know if we can do it
Cheers
JC
Add the following to g-code to the very end of the “Machine end G-code” section of the printer profile (ie. “Bambu Lab P1S 0.4 nozzle”) you are using:
G4 S300 ; wait 5 minutes
M106 P3 S0 ; turn off chamber cooling fan
Save it as a custom Printer profile ie. “Bambu Lab P1S 0.4 nozzle (ABS)”
Use that profile when you print with ABS.
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Well,
This is what it looks like.
I just finished a test print, and it doesn’t wait 5 minutes, but turns the fan off immediately.
And then a couple of minutes later, the fan turns on.
I’m confuzzled.
I suspect that fan set-up in filament is bypassing or has priority other this instruction
When you said a couple of minutes it’s not 5 minutes?
Did you look what you have inside the gcode file ?
JC
What does the “Filament end gocde” look like in your filament profile?
Look for “M106 P3” commands in your G-code to help figure out what is going on. It is the command to control the chamber fan.
M106 P1 (or no P1) < Part Fan
M106 P2 < Aux Fan
M106 P3 < Chamber Fan
My apologies, I missed a code change I should have told you about.
If you look towards the top of “Filament end gocde” you should see the following lines:
M106 S0 ; turn off fan
M106 P2 S0 ; turn off remote part cooling fan
M106 P3 S0 ; turn off chamber cooling fan
Change the last line so it looks like this:
;M106 P3 S0 ; turn off chamber cooling fan
M106 P3 S255 ; exhaust chamber at full fan speed
(if you just comment it out with that first line, I believe is will continue to run the fan at whatever speed the filament profile is set for exhaust fan)
This is how I run my … nozzle (ABS) profile:
M106 P3 S255 > turns the fan to full speed before the rest of the print finish actions happen, like retracting filament, parking the bed, parking the tool head etc.
If you only want to run it at 50% then use “S127” instead of S255.
When it gets to the end…
G4 S300 > makes it wait (in seconds) before it moves on the next command.
M106 P3 S0 > turns the chamber fan off
No change. The fan is running at 70%.
So here is the entire section as it is now:
;===== date: 20230428 =====================
M400 ; wait for buffer to clear
G92 E0 ; zero the extruder
G1 E-0.8 F1800 ; retract
G1 Z{max_layer_z + 0.5} F900 ; lower z a little
G1 X65 Y245 F12000 ; move to safe pos
G1 Y265 F3000
G1 X65 Y245 F12000
G1 Y265 F3000
M140 S0 ; turn off bed
M106 S0 ; turn off fan
M106 P2 S0 ; turn off remote part cooling fan
;M106 P3 S0 ; turn off chamber cooling fan
M106 P3 S255
G1 X100 F12000 ; wipe
; pull back filament to AMS
M620 S255
G1 X20 Y50 F12000
G1 Y-3
T255
G1 X65 F12000
G1 Y265
G1 X100 F12000 ; wipe
M621 S255
M104 S0 ; turn off hotend
M622.1 S1 ; for prev firware, default turned on
M1002 judge_flag timelapse_record_flag
M622 J1
M400 ; wait all motion done
M991 S0 P-1 ;end smooth timelapse at safe pos
M400 S3 ;wait for last picture to be taken
M623; end of "timelapse_record_flag"
M400 ; wait all motion done
M17 S
M17 Z0.4 ; lower z motor current to reduce impact if there is something in the bottom
{if (max_layer_z + 100.0) < 250}
G1 Z{max_layer_z + 100.0} F600
G1 Z{max_layer_z +98.0}
{else}
G1 Z250 F600
G1 Z248
{endif}
M400 P100
M17 R ; restore z current
M220 S100 ; Reset feedrate magnitude
M201.2 K1.0 ; Reset acc magnitude
M73.2 R1.0 ;Reset left time magnitude
M1002 set_gcode_claim_speed_level : 0
M17 X0.8 Y0.8 Z0.5 ; lower motor current to 45% power
G4 S300 ; wait 5 minutes
M106 P3 S0 ; turn off chamber cooling fan
Thoughts?
Hi
Seems that it’s not possible to do it
Did you had a look at the very end of the .gcode file ? I’m sure you’ll find something like
M106 P3 Sxxx ; with xxx equal to speed define in filament set-up
Cheers
JC
It is possible to do it, because mine is does it.
I believe I remember having the same issue when I first set mine up to exhaust.
I am trying to remember what I had to do to resolve it.
It is indeed the filament profile. It looks like they are set to 70% (M106 P3 S180) by default.
If you are using a P1P there is “support_air_filtration” flag that is turned off in the base profiles. The P1S has this flag enabled. For some reason this makes the Chamber Fan not follow the Printer Profile G-Code.
I ended up just commenting out the G-code in the filament for any filaments I wanted to run the chamber fan for.
Here is my example for ABS.
Under Cooling:
Active air filtration: (check the box)
During print: 30%
Complete print: 0% (I bet this is what is overriding your Print Profile G-code as it default to 70%)
Under Advanced:
Filament Start G-code:
; Filament gcode
;{if activate_air_filtration[current_extruder] && support_air_filtration}
M106 P3 S{during_print_exhaust_fan_speed_num[current_extruder]}
;{endif}
I had to comment out the if/endif, as the lack of “support_air_filtration” flag was causing it not execute since I have a P1P.
This statement reads the % you set under the cooling tab:
M106 P3 S{during_print_exhaust_fan_speed_num[current_extruder]}
If you have anything but 0% set for “Complete print” it will override the ABS print profile you added the custom G-code to.
I hope that fixes you up.
Let us know!
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After thoughts about this…
It is stupid they even include the “support_air_filtration” flag at all. If the printer doesn’t have a chamber fan, even executing a M106 P3 command wouldn’t do damn thing anyhow, so why even test for it in the condition.
I believe it is legacy code left over from Prusa Slicer or Slic3r, as all of this code has been ad hoc for such a long time and carries with it lots of spaghetti and legacy code.
Hi and thanks for all these details
I’m having a P1S and by default the flag is disabled 
I printed a part this afternoon (French time) with Bambu Lab ABS using standard profile and chamber fan wasn’t running during and after printing.
I’ll do some test tomorrow as I’m curious to understand how it’s managed
Cheers
JC
Made the change to 0 after print and it shuts down.
Thank you for your assistance.
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