Klipper calibration order

Calibrate in this sequence: 1. rotation distance → 2. flow / max volumetric speed → 3. pressure advance → 4. shrinkage (dimensional accuracy). The order matters because each step assumes the previous one is right: flow tests are meaningless if the extruder feeds the wrong amount of filament, pressure advance is tuned at a speed you only know after step 2, and dimensional calibration last because part dimensions depend on all three. Work through the steps below top to bottom and you only do each once.

1. Rotation distance — how much filament is fed

What it fixes: consistent over- or under-extrusion on every print, in every slicer profile.

How the tool computes it: mark the filament 120 mm above the extruder inlet, extrude 100 mm (G91, then G1 E100 F60 — make sure max_extrude_only_distance is at least 101), and measure what actually went through. The rotation distance calculator applies new = old × actual ÷ requested — the ratio is inverted versus Marlin e-steps because rotation_distance is millimeters per revolution.

Paste into printer.cfg under [extruder]: rotation_distance: 7.585 (your computed value), then RESTART and repeat the test once to confirm.

This comes first because rotation distance is a mechanical property of the drive gears — everything that follows prints plastic, and plastic printed with a wrong feed rate miscalibrates every later step.

2. Flow / max volumetric speed — how fast you may print

What it fixes: under-extrusion, weak layers and skipped steps that only appear at higher speeds — the hotend physically cannot melt filament fast enough.

How the tool computes it: layer height × line width × speed is the volume your hotend must melt each second. The volumetric flow calculator shows that demand against your hotend's limit, and the max print speed calculator reverses the formula to give the fastest safe speed for your layer settings. Run a max-flow test on your own setup before trusting the number at the edge — preset values are PLA-style figures.

Nothing goes into printer.cfg here — flow limits live in the slicer (max volumetric speed / speed caps). Set them now, because the next step is tuned at the speed you actually intend to print.

3. Pressure advance — sharp corners at speed

What it fixes: bulged corners, gaps at the start of extrusion moves, and ringing-like artifacts from pressure lag inside the melt zone.

How the tool computes it: print the pressure-advance tower (stepping the value as it prints, per the Klipper docs), find the height with the cleanest corners, and the pressure advance calculator applies PA = start + height × factor. Tune it at your real print speed from step 2 — pressure lag is speed-dependent, which is exactly why this comes after flow.

Paste into printer.cfg under [extruder]: pressure_advance: 0.04 (your computed value), then RESTART.

4. Shrinkage — dimensional accuracy

What it fixes: parts that come out consistently too small or too large — holes that don't fit, pegs that don't mate.

How the tool computes it: print a calibration cube, measure it with calipers, and the shrinkage compensation calculator gives the new slicer scale: new scale = current scale × designed ÷ measured. Successive corrections multiply, they don't add.

Slicer setting, not printer.cfg — apply the scale in your slicer's filament or print profile. This step comes last because measured dimensions only mean something once extrusion (step 1), speed (step 2) and corner behavior (step 3) are stable.

When to redo the sequence

• Nozzle swap or hotend work — redo pressure advance and re-check max flow; a worn or different nozzle changes melt behavior.
• New filament brand or material — redo pressure advance and shrinkage (shrinkage is strongly material-dependent); rotation distance normally survives a filament swap.
• Extruder gear or motor change — redo rotation distance from step 1; the drive geometry changed.
• Firmware update — printer.cfg survives updates, so nothing resets — but re-run rotation distance and pressure advance if the update changed default motion behavior.