I’m printing ABS on a Bambu Lab P2S and trying to maintain a chamber temperature of around 50–60°C.
However, I can’t find any settings in Bambu Studio that control chamber heating or auxiliary fan behavior. In the ABS filament profile, the auxiliary fan is set to 0%, but when the print starts, the printer automatically ramps it up to 100%.
Because of this, the chamber temperature drops significantly, and I have to manually reduce the auxiliary fan speed every time I start a print.
Has anyone experienced this or knows where this behavior is controlled? Is there a hidden setting or override I’m missing?
I’ve already tried searching and asking GPT/Google, but couldn’t find a solution.
The P2S doesn’t have active heating so there is no control of it via Bambu Studio. The best way to “heat” the chamber is to turn the bed on full for 15-20 minutes before a print. Raising the bed to the top and turning on the AUX fan will help to move the air around the chamber and heat soak it. This technique will normally get your 50ish c chamber temp depending on your ambient temperature.
For ABS prints The Aux fan should be sent to 0 for the entirety of the print.
Another option is to use a 3rd party chamber heater.
But main problem - 100% aux fan. How to delete/remove this option?
Talking to myself:
“I can manually chose cooling or heating mode.
So why we don’t have this option in filament profile.
And it also good to have automatic pre-heat mode”
I’m not sure what problems you may have printing using ABS, but, I’ve printed plenty of models with ABS and have not had to change any default settings.
I am talking about side/auxiliary fan.
I am switching it off manually every time.
but it hard to remember every time. I am looking for way to automate it
First, we need to clarify which aux fan is which. Bambu doesn’t clearly define them so maybe this will help.
The right side aux fan (P2) is built-in and operates in two modes; cooling or heating. In cooling mode it brings outside air in from underneath the printer and blows it out over the heat bed. In heating mode, it recirculates the chamber air, drawing it through the carbon filter and blowing it back into the chamber through a lower grill, normally below the heat bed. Heating mode does NOT draw outside (cool) air into the chamber. Nor does it provide any heat. It retains the chamber heat, produced by the heat bed and hot end, by not diluting it with outside air.
The left side aux cooling fan (P10) is optional. Unless you have specifically purchased and installed this option, you don’t have it. It simple recirculates chamber air, drawing from the bottom and blowing out over the heat bed. This is the aux fan that is referenced at the bottom of the filament cooling settings as a minimum speed. The printer will automatically adjust this fan speed during a print.
ABS prints with heating mode, so there is no need to stop the (right side) aux fan.
I am printing a lot of ABS. And when Right fan 100% heating mode - chamber temperature is 37-42C. When Right fan OFF - chamber temperature is 50-52C.
Some people use default bambu ABS profile (Right fan 100% heating mode) and have no any problem. I belive theirs models are small and layer time is also small so require more cooling.
the mail problem is that is filament profile only one setting Aux Fan. It set to 0%.
I dont know which fan is in filament profile.
And where is Right fan adjustment.
Accidentally I found code in Printer profile - Machine Start G-Code:
but I have no idea how to set right fan to 0% only for ABS
definitelly “M145” - airduct mode, “M145 P0” - cooling, “M145 P1” heating
“M106 P2” - auxiliary fan
“M106 P3” - chamber fan
;==== set airduct mode ====
;==== if Chamber Cooling is necessary ====
{if (overall_chamber_temperature >= 40)}
M145 P1 ; set airduct mode to heating mode for heating
M106 P2 S255 ; turn on filter fan
M622.1 S0
M1002 judge_flag ventobox_replace_aux1_fan_flag
M622 J0
M106 P10 S0 ; turn off left aux fan
M623
{else}
{if (min_vitrification_temperature <= 50)}
M145 P0 ; set airduct mode to cooling mode for cooling
M106 P2 S255 ; turn on auxiliary fan for cooling
M106 P3 S127 ; turn on chamber fan for cooling
M1002 gcode_claim_action : 29
M191 S0 ; wait for chamber temp
M106 P2 S102 ; turn on chamber cooling fan
M622.1 S0
M1002 judge_flag ventobox_replace_aux1_fan_flag
M622 J0
M106 P10 S0 ; turn off left aux fan
M623
M142 P6 R30 S40 U0.3 V0.8 ; set PETG exhaust chamber autocooling
{else}
M145 P1 ; set airduct mode to heating mode for heating
M106 P2 S127 ; turn on 50% filter fan
M142 P6 R30 S40 U0.3 V0.8 ; set PLA/TPU exhaust chamber autocooling
{endif}
{endif}
;==== set airduct mode ====
