Pressure Advance tuning
Pressure Advance (PA) is a Klipper feature that compensates for the pressure lag in the melt zone — the delay between when the motor commands more flow and when molten material actually reaches the nozzle. In FGF (pellet) printing, the melt volume is much larger than in filament printing, so PA behavior is different.
What the machine actually starts with
Section titled “What the machine actually starts with”Two things set Pressure Advance, in this order.
The printer profile sends PRESSURE_ADVANCE=0.2 and
PRESSURE_ADVANCE_SMOOTH_TIME=0.5 at the start of every print. That pair is the
same on all five nozzles — Pressure Advance is not a per-nozzle setting.
The material profile then overrides the first number with its own, and every shipped profile but one does exactly that. So 0.2 is what you get only if the material you picked leaves Pressure Advance switched off.
Smooth time stays at 0.5 throughout.
When PA helps
Section titled “When PA helps”- Blobs or over-extrusion at corners and direction changes
- Oozing during travel moves
- Inconsistent line width at the start and end of each pass
When PA does NOT help (or causes problems)
Section titled “When PA does NOT help (or causes problems)”- Under-extrusion overall → adjust Rotation Volume first, not PA
- Layer shifting → belt/mechanical issue, not PA
- Very high PA values can fail at the purge line — a value around 0.75 in vase mode has thrown an error immediately after the purge. Note that the shipped 20% filled PETG profile sits at 0.7, so the problem is not the number alone but the number combined with vase mode. If it happens, come down in steps rather than dropping to a default.
Tuning procedure
Section titled “Tuning procedure”Pressure Advance is set only from Ginger Slicer, in the material profile.
Not from the console, not from the display, and not in printer.cfg.
- Set a value in the material profile and slice a test part with sharp corners
- Print it and examine the corners: look for the value where they are sharpest without under-extrusion
- Change the value in the profile and repeat
What the shipped material profiles use
Section titled “What the shipped material profiles use”| Material profile | Pressure Advance |
|---|---|
| Every PLA and rPLA profile | 0.3 |
| Plain PETG | 0.25–0.3 |
| PETG 10% filled | 0.5 |
| PETG 20% filled | 0.6–0.7 |
| PP | 0.2 |
The pattern is the useful part: the more filler in the grade, the more Pressure Advance it wants, and it climbs steeply — a 20% filled PETG runs at more than twice the value of the unfilled one. Unfilled grades sit in a narrow band around 0.3 and rarely need touching.
Start from the profile for the grade in your hopper. Tune from there, not from these rows — they are what Ginger ships, and the grade decides.
Vase mode (Spiral vase)
Section titled “Vase mode (Spiral vase)”Vase mode (Spiral vase): set Pressure Advance to 0 when using vase mode. Any PA value creates visible artifacts on the continuous spiral wall — the compensation pulses appear as a repeating texture on the outer surface. PA = 0 produces the smoothest result for vase mode prints.
- At very high MVS values (> 300 mm³/s), PA becomes less effective; prioritize Rotation Volume calibration first