In doing some manual pressure advance calibration, using the scripts built into Orca Slicer, I found some strange behavior.
While the test starts out as you would expect, with some under-extrusion at the beginning of the fast print move, and over-extrusion at the end (not enough PA); as you move through “ideal” PA and into “too much” PA, the behavior is not good.
Rather than seeing the over-extrusion and under-extrusion switch positions on the print line, we see a return to the “under PA” behavior, but worse.
To me, it is looking like the extruder is skipping steps:
Material: Bambu PLA
Speed: 20 - 180 mm/s
Accel: 8000 mm/s2
Layer height: 0.2 mm
Line width: 0.6 mm
PA Range: 0.010 - 0.030