Before changing a calibration value
Identify the steel sheet surface and the selected filament profile. Prusa’s first-layer guide starts with correct surface preparation; automatic measurement cannot establish that the surface has been prepared for the material.
The loadcell article explicitly says routine manual Live Z adjustment and saved steel-sheet calibration profiles are not necessary for this system: measurements are taken before each print. Do not follow an older printer’s manual-calibration advice simply because it describes a similar-looking first layer.
Prusa Knowledge Base · help.prusa3d.comPrusa Research · help.prusa3d.com
Use the test as a decision point
The official route is LCD Menu → Control → Calibration & Tests → Loadcell Test. Follow the on-screen timing; do not touch or manipulate the printer unless the screen asks you to. If the progress bar does not fill or an error appears, Prusa directs users to customer support.
The wider first-layer guide also includes expansion-joint orientation and nozzle seating. Those are hardware-specific branches, not permission for trial-and-error adjustment. When a check calls for handling components, follow its cooling and power-off instructions; do not substitute a generic cleaning or tightening routine.
Prusa Knowledge Base · help.prusa3d.comPrusa Research · help.prusa3d.com
FAQ
Original Prusa MK4S frequently asked questions
Each answer stays within the facts and sources shown on this page.
01Does MK4S require manual first-layer calibration?
The product page says first-layer calibration is fully automatic through the Loadcell sensor. If the first layer is still uneven or does not adhere, use the model-applicable checks rather than immediately changing Z height.
02What should I check first for a bad MK4S first layer?
Start with the correct sheet-cleaning procedure for the material, then check expansion-joint orientation. Follow Prusa’s cooled-and-powered-off condition before checking nozzle seating, and run the LoadCell test from the printer menu. Stop if a step is unclear or would put your hands near a hot toolhead.
03Does automatic first-layer calibration eliminate all MK4S adhesion checks?
No. Loadcell measurement removes the need for routine manual Live Z and steel-sheet calibration profiles, but surface preparation and the documented first-layer checks still apply. Automatic measurement is not proof that the plate is clean or the material setup is correct.