Guide · Measurement tools
Pressure advance and Linear Advance: what to tune and when
What pressure advance compensates, why it is set per extruder, nozzle and filament, the typical Klipper range, Marlin's K-factor unit change, and the tuning order.
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Short answer
Pressure advance (Klipper) and Linear Advance (Marlin) compensate for the lag between the extruder moving and plastic leaving the nozzle. The value belongs to an extruder, a nozzle and a filament, not to the printer. Tune extruder calibration and temperature first, then pressure advance, and re-check it after input shaping.
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What it compensates
Molten plastic in the nozzle is under pressure. When the print head speeds up, it takes a moment for that pressure to build; when it slows down, the pressure keeps pushing plastic out. The result is thin starts and bulging corners. Pressure advance and Linear Advance move the extruder slightly ahead of that lag.
Klipper says pressure advance does not change print time or the total filament extruded.[1]
It is set per extruder, nozzle and filament
Klipper says the pressure advance value depends on the extruder, the nozzle and the filament, and recommends calibrating it on each printer and with each spool. Filament from different makers, or with different pigments, can need significantly different values.[1]
Marlin says the same of its K-factor: it depends on filament, print temperature, extruder type and nozzle, and should be recalibrated if any of these change.[2] Marlin also notes that very flexible filaments may not work with it at all.
Typical range, and Bowden
Klipper gives typical values of 0.050 to 1.000, with the upper end usually needed only on Bowden extruders.[1] It warns that values over about 0.200 can make the extruder skip, and that no setting limits the resulting extruder movement. Its tuning-tower factor is .005 for direct drive and .020 for Bowden.
The order to tune in
| Order | Step | Source |
|---|---|---|
| 1 | Extruder rotation distance or E-steps | Klipper; Marlin says steps/mm must be precise first |
| 2 | Nozzle temperature | Klipper |
| 3 | Pressure advance or Linear Advance | |
| 4 | Input shaping, then re-check pressure advance | Klipper; Marlin M593 |
| 5 | Flow ratio per filament | See the flow guide |
Klipper tells users to tune extruder rotation_distance and nozzle temperature before tuning pressure advance.[1] Marlin says extruder steps/mm must be calibrated precisely first.[2] The E-steps and rotation distance guide covers step 1.
Re-tune after input shaping
Klipper's ringing-test procedure disables pressure advance during the test, and says to re-tune pressure advance after shaper tuning if needed, after restarting Klipper.[3] Marlin's M593 page similarly notes that the Linear Advance K-factor may need recalibration after input-shaper tuning.
Marlin's K-factor unit changed
Marlin changed the unit of the Linear Advance K-factor in version 1.5. Old K values, around 30-130 for PLA, do not carry over to the new range of about 0.1-2.0, and Marlin says you have to redo the calibration.[2] If a forum post gives a K of 50, it was written for the old unit.
M900 K0 disables Linear Advance.[4] That is a useful reset if you are not sure where a value came from.
Klipper documents a typical pressure advance range of 0.050 to 1.000, and Marlin a K range of about 0.1-2.0. They are different settings in different firmware, so do not assume a number carries from one to the other: calibrate on the firmware you run.
Next
Questions
Do I tune pressure advance per filament?
Klipper says the value depends on the extruder, the nozzle and the filament, and recommends calibrating it on each printer and with each spool. Filament from different makers or with different pigments can need very different values.[1]
Why is my Marlin K value 50 when the guide says 0.05?
Marlin changed the K-factor unit in Linear Advance 1.5. Old values (around 30-130 for PLA) do not carry over to the new range of about 0.1-2.0, so you have to redo the calibration.[2]
Should I tune pressure advance before or after input shaping?
Klipper's ringing test disables pressure advance and says to re-tune it after shaper tuning if needed. Marlin's M593 page similarly notes the K-factor may need recalibration after input-shaper tuning.[3]
What is a typical pressure advance value?
Klipper gives 0.050 to 1.000 as typical, with the upper end usually needed only on Bowden extruders. It warns that values over about 0.200 can make the extruder skip.[1]