Part fan reverts to 80% but Gcode sets at 100%

Bambu Lab P1 Series Troubleshooting
1

I’m having a strange issue. For some reason even when the last fan command gcode is

M106 S255
M106 P2 S255

The fan speed seems to only go up to 80%. I can set it manually and it works for ~5 minutes but then REVERTS back to 80%. Turning fan ON in the p1p display also has the same behavior.

Anyone else having this issue?

Additionally the K-value shown in the Device menu is not what it is in the GCODE. Seemingly that reverts, as well.

Example GCODE

; filament start gcode
M106 P3 S255
M900 K0.03 L1000 M10 ; Override pressure advance value

image

2

I don’t have a P1P

You can set your fan to something like this in the slicer if you want the part fan @ 100% after layer 1

Fanpart
Fanpart727×224 17 KB

You might have to put it in the machine start G-code at the end

M975 S1 ; turn on mech mode suppression
M900 K0.03 L1000 M10 ; Override pressure advance value

3

The plot thickens. Bambu Handy app shows nothing for a K value. Setting part fan also reverts after 5 mins.

Screenshot_20230523_154352_Bambu Handy_1
Screenshot_20230523_154352_Bambu Handy_11080×1327 88.9 KB

4

My settings are the same as this, but Min fan was at 90% instead (and layer time differences). I don’t see any GCODE in which the fan is set anything under 255 speed, my gcode above is the last line before the entire rest of the print.

Good idea on the pressure advance in start gcode, I will try that as well!

5

Try the fan setting above it must be overriding your manual G-code settings.

Sound like you have looked at all your G-code if not this is what I use use - clicking on the G-code tab.

G-code Viewer

or Orca slicer

6

You were right! Setting min and max to 100 fixed it.

It’s strange, though, that with Min at 90 the Bambu puts it at 80 but in Handy it’s 90. Must be a bug.

Pressure advance even with your start Gcode seems set at default 0.020 in the desktop slicer but in Handy it’s still what it shows above. Strange. I assume it is working, and that this is another bug.

7

It’s strange, though, that with Min at 90 the Bambu puts it at 80 but in Handy it’s 90. Must be a bug.

Ya must be bug.

Pressure advance even with your start Gcode seems set at default 0.020 in the desktop slicer but in Handy it’s still what it shows above. Strange. I assume it is working, and that this is another bug.

If you run a pa test you should see the test results change that way you know 100% its working ok.

Have a good one :v:

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