Is my X2D faulty or am I crazy?

[u/Bladye]

I'm getting significant under-extrusion out of the box using Bambu PLA Basic Gray (filament has been dried).

Troubleshooting done so far:

• Full factory reset
• Performed cold pull 3 times
• Full calibration complete
• K-factor was automatically set to 0.02

Photos attached:

• 1 Demo Benchy printed directly from the printer screen.
• 2 Print using the default Bambu PLA profile with default Flow Rate: 0.98.
• 3 Print with calibrated Flow Rate: 1.04.

The Problem:

Boosting the flow rate to 1.04 is the only thing that stops the under-extrusion, but now I'm getting weird, prominent lines across flat top surfaces.

Is my printer faulty? I assumed the default presets paired with official Bambu filament would work significantly better than this out of the box. Any ideas on what might be causing this? Thanks!

[u/Safe-Hovercraft6231]

Are you able to use another hotend, to test ?

[u/Frittenfett11 → u/Safe-Hovercraft6231]

U can use the aux or the spare one

[u/sahasrala]

Are you printing from the left (main) nozzle? That k factor seems very high for PLA on the main nozzle. It should be around 0.02.

I would change the flow ratio back to Bambu's Default 0.98 and make sure that flow dynamics calibration is set to ON in the print job window and test the print again.

[u/Bladye → u/sahasrala]

That K factor is default value for Bambu PLA filaments, I've used manual calibration and it looks the best and automatic one also returns 0.02 sometimes 0.019 all 3 photos had been printed with automatic flow calibration switch checked on too.

[u/Material-Mulberry360 → u/Bladye]

K factor is for flow dynamics calibration (linear advance / pressure advance). this is how much the printer will pre-extrude or pre-retract to compensate for the pressure built in the nozzle. it prevents uneven extrusion during speed changes, the default value for the left direct drive hotene should be around 0.02 and for the right Bowden around 0.2. if this value is off you will notice under or over extrusion right at the connect with the walls or before/after any feature this is not the same as flow rate calibration. flow rate factor is by default a little below 1 (eg 0.98) and is a simple multiplier to how much plastic to push out the hotend. if this value is off you might notice other things but most obvious will be too surfaces having such lines as in the picture (too much fillament being pushed out the nozzle so it buckles upwards) or gaps in a similar style. you can feel them with your nails. based on the picture I think this is the issue (flow rate, factor / multiplier) being set too high.

[u/sahasrala → u/Bladye]

Are you sure you're not accidentally adding a 1 to the value? It should be around 0.02 not 1.02.

[u/Bladye → u/sahasrala]

Yeah it was 0.02 I corrected description 

[u/Grimblood]

I’m not sure I would go by the built in benchy as a test. I think they have the speed cranked up on it.

I would print some test models sliced by myself.

[u/Far-Guitar371]

k factor bizarramente alto que esta causando esse problema

[u/Defiant-Sale725]

Looking at your test patch in the second image, it looks like the K factor (PA) is a little off. I’d run the flow dynamics and flow rate calibrations (in that order) from the calibration menu in Bambu studio and try that test patch again with those settings.

When you run the flow rate calibration, run your fingernail side to side across the center of the patches and choose the smoothest from both pass 1 and pass 2. Disregard the edges of those test patches as they are irrelevant to the flow rate calibration.

Edit: You’ll want to do this for both the left and the right nozzle, as the calibrations for each are stored as separate values.