3D printer calibration

E-steps: mark the filament 120 mm above the extruder, extrude 100 mm slowly at printing temperature, and measure what is left to the mark. New steps/mm = old × requested ÷ actual. Klipper’s rotation_distance goes the other way: new = old × actual ÷ requested.

Belts: steps/mm = motor steps × microsteps ÷ (pulley teeth × belt pitch); Klipper’s rotation_distance is teeth × pitch. Lead screws: divide by the lead (pitch × starts).

Flow: print a single-wall cube, measure each wall, and scale the flow by expected ÷ measured. Calibrate e-steps first.

Scale: per-axis slicer scale = designed ÷ measured × 100 %, best done per material.

Z offset: in Marlin a more negative M851 Z moves the nozzle closer; a larger Klipper probe z_offset moves it closer.

Bambu / Orca: Bambu printers have no e-steps or Z offset to set; what you calibrate is per filament. Print the tests from the Calibration menu of Bambu Studio or OrcaSlicer and read them on this tab: flow dynamics / pressure advance K from the tower (K = start + step × height; the line and pattern tests print K beside each line), the flow ratio from the YOLO blocks (old + modifier) or the two-pass blocks (old × (100 + modifier) ÷ 100), max volumetric speed from the tower (start + height × step, then keep 10–20 % below it, and the fastest line that allows at your layer height and line width), and retraction from the tower. The formulas are the ones the OrcaSlicer wiki gives. The Bambu 3MF inspector shows these values for each filament in a project.