Before You Calibrate: The First Print Check

What this check is for

Every calibration test changes one setting and asks you to judge the result. That only works if everything else on the printer is already sound. A temperature tower printed with a half-clogged nozzle, or a flow test printed on a first layer that is too close to the bed, gives you a confident wrong answer. This page is the short list of things to confirm before you print any tower.

Step 1: run the printer's own routine

Most current printers ship with a setup routine that checks the hardware and tunes what it can measure itself. Run it before anything else, and run it again after you move, repair or rebuild the printer.

• Prusa MK4/S and MK3.9/S: the printer starts a selftest the first time it is switched on. Prusa lists fan checks, a loadcell test, X, Y and Z axis checks, nozzle and heatbed heater checks, gearbox alignment and a filament sensor test. The loadcell, gearbox and filament sensor steps need your input, so stay at the printer. Keep the firmware up to date, as Prusa asks.
• Bambu Lab A1 mini: before finishing setup, Bambu Lab recommends ticking Vibration Compensation and Motor Noise Cancellation and starting the calibration, which it says usually takes about 12 minutes Maker spec. When starting a print, Bambu Lab recommends keeping bed leveling and dynamic flow calibration enabled.
• Klipper printers you configured yourself: work through Klipper's configuration checks: confirm temperatures read correctly and do not climb on their own, confirm the M112 emergency stop works, confirm each heater warms and cools, each endstop reports open and triggered, each stepper moves the right way, and the extruder turns the right way. Then run PID_CALIBRATE HEATER=extruder TARGET=170 (and the bed equivalent if the bed supports PWM control) and SAVE_CONFIG. Klipper says PID values copied from other firmware or example configs often work poorly.

Step 2: the extruder moves the right amount

OrcaSlicer's calibration guide assumes the extruder is already calibrated in firmware (E-steps or rotation distance), and notes that most modern printers ship with this set correctly. Small differences between filaments are corrected later in the flow test, not here.

Only check this yourself on a printer whose firmware configuration you control, such as a Klipper build. Klipper's method is "measure and trim": heat the hotend to printing temperature first (Klipper will not extrude cold), make sure filament is loaded, then mark the filament about 70 mm above the extruder intake, extrude 50 mm slowly with G91 then G1 E50 F60, and measure how far the mark actually moved Starting point. Klipper warns not to use a front-end's extrude button, because it extrudes too fast and the pressure skews the result.

Klipper also warns that this method is not accurate enough for the X, Y or Z axes and will likely make them worse. Do not use it to chase a part that measures a little large; see Dimensional Accuracy for that.

Step 3: a first layer you trust

Every calibration print starts with a first layer, and OrcaSlicer and Bambu Lab both say their pressure advance line test depends heavily on first layer quality. Before you print a tower:

• The bed is clean and trammed as your printer intends: Bed Tramming, Probing and Mesh Compensation. Set the Z offset before building a bed mesh, because recalibrating the probe invalidates the mesh.
• The nozzle height is right: Z Offset and First Layer Height.
• Lines are flat, touching and stuck: First Layer Fundamentals, and if they are not, First Layer Won't Stick.

Step 4: one plain print with the maker's profile

Print something small with the printer maker's own profile and the filament maker's own profile, changing nothing. If it prints well, you may not need any filament calibration for that material. OrcaSlicer's guide notes that the flow ratio in most filament profiles is already close. Calibrate when a specific problem shows up, or when you change to a filament with no tuned profile.

Step 5: the order of tests

Tests interact, so the order matters. Use the order your slicer or firmware documents.

Source	Order it gives
OrcaSlicer calibration guide	Temperature, then max volumetric speed, then pressure advance, then flow ratio, then retraction. Repeat these for each new filament. Optional printer tests (cornering, input shaping, VFA, adaptive pressure advance) come after, and tolerance comes last.
Klipper configuration checks	Pin and heater checks and PID tuning, then the bed leveling guide. Once basic printing works, consider pressure advance.

OrcaSlicer explains why pressure advance comes before flow ratio in its order: pressure advance is the value most often wrong, while the flow ratio in most filament profiles is already close. It adds that the two affect each other slightly, so if the flow ratio changed a lot, run a quick pressure advance test again.

Rules for every test

• One variable at a time. Leave everything except the setting under test at the profile's value.
• Same spool, same conditions. Results belong to one printer, nozzle and filament.
• Save the result where it belongs. OrcaSlicer's filament tests are saved to the filament profile, so they follow the material.
• Leave calibration mode. OrcaSlicer reminds you to create a new project after calibrating, to exit calibration mode.

Which test answers which problem

What you see	Start with
First layer not sticking, or ridged and scraped	Z offset
Weak layers, poor bridges, stringing with a new filament	Temperature tower
Gaps between top lines, or a rough, ridged top	Flow calibration
Bulging corners, thin line starts	Pressure advance
Hairs between parts	Retraction test, after the above
Parts or holes the wrong size	Dimensional accuracy, last