Multi-Heating Zones

The G1 pellet extruder has three independently controlled heating zones along the extrusion barrel. Unlike a filament hotend with one temperature, the G1 needs to manage compression, melting, and final flow as separate stages.

The three zones

Zone	Position	Purpose
Feeding Zone (Zone 1 / T0)	Top, near hopper	Initial heating and pellet compression
Melting Zone (Zone 2 / T1)	Middle	Completes melting; ensures homogeneous flow
Nozzle Zone (Zone 3 / T2)	Bottom, at nozzle	Maintains the right viscosity for stable extrusion onto the bed

Each zone has its own thermistor (NTC 100k) and heater band. They are tuned independently in the slicer’s material profile.

Zone numbering

In Ginger Slicer	The band	On the display / in Klipper	Zone
Zone 1	T0	`extruder`	Feeding Zone (top)
Zone 2	T1	`extruder1`	Melting Zone (middle)
Zone 3	T2	`extruder2`	Nozzle Zone (bottom)

The slicer exposes nothing else about the zones — just the three temperatures.

The G1 display showing the temperature list: Extruder, Extruder1 and Extruder2 with their current values, alongside Heater Bed

From How the G1 Automatic Feeding System works — 2:39

Recommended starting temperatures

Begin with uniform temperature across all three zones, then fine-tune per material grade.

Polymer	Starting temperature (all zones)
PLA	the value in its profile
PETG	the value in its profile

The G1 is supported on PLA and PETG. Other polymers can be extruded but Ginger does not characterise them — see Materials.

On the 1 and 1.8 mm nozzles the flow is slow and the back-pressure high, and the melt creeps back up into the Feeding Zone. The fix is directional, not a fixed number: come down on the top zone, leaving the other two where the material profile puts them. The shipped profiles already do this — several PETG ones set Zone 1 fifteen to forty degrees below the other two.

How far down depends on the grade. For scale, the shipped PLA profiles run their Feeding Zone between 185 and 215°C, and the lowest Feeding Zone in the whole set is the 170°C that Generic PP uses against a 240°C melt zone — the largest gap any profile asks for. Start from your profile and work down in steps.

If the top zone reads much higher than its setpoint despite a low target, the heat is arriving from below rather than from its own band, and active cooling above the barrel throat is what helps.

Tuning per zone

Feeding Zone

The Feeding Zone temperature follows the nozzle and the flow rate. The starting temperatures above are a baseline — expect to adjust the Feeding Zone whenever you change nozzle:

Situation	What goes wrong	Adjustment
Small nozzle, low flow	Material dwells in the Feeding Zone and clogs there	Lower the Feeding Zone
Large nozzle, high flow	Material moves through too fast to soften properly	Raise the Feeding Zone

A smaller nozzle also raises back-pressure in the barrel, which pushes molten material upward into the Feeding Zone (heat-creep). When switching to a smaller nozzle, always reduce the Feeding Zone temperature — see the nozzle-specific notes above.

Lower it (by ~10°C) when:

Melt is creeping up into the feed throat / hopper (a clog forming above the screw)
Using small-cut pellets (< 3mm, or 1.75mm cylindrical grades) — smaller pellets have more surface area relative to volume and need less thermal energy to reach melt temperature; they soften too early in the Feeding Zone and form a plug before compression completes
Pellets are fines-heavy (premature softening causes plug)
Printing very slowly and pellets sit too long in the heated barrel

Raise it (by ~5–10°C) when:

Irregular under-extrusion suggests insufficient compression
Using SmoothFlow or Liquid Masterbatch (additives can reduce friction; higher temp restores compression)
The screw struggles to “bite” the pellets

Melting and Nozzle Zones

These usually stay stable around the recommended polymer temperature. Adjust mainly to ensure complete melting without burning or degrading the material:

Too cold → solid bits in the extrudate, motor strains, layer adhesion suffers
Too hot → polymer degradation, browning, weak parts, smoke

Diagnosing temperature vs. Rotation Volume issues

The shape of the fault tells you which knob to reach for. An unsteady extrusion is never a Rotation Volume problem — fix the steadiness first, then calibrate.

What you see	What it means	What to do
Irregular extrusion — hiccups in the flow, more or less pronounced	The material is slipping in the Feeding Zone	Tune the Feeding Zone temperature
Nothing comes out at all	The material has clogged in the Feeding Zone	Clear the clog — see Extruder screw
Consistently too much or too little, but steady	Rotation Volume is wrong for this material	Calibrate Rotation Volume
Bubbles, popping sounds	Wet pellets, not temperature	Dry the pellets — see PETG foaming and moisture

Calibrating Rotation Volume from a printed part

This is quick — no test print needed beyond what you already have. Measure the printed wall thickness, compare it with the target thickness set in the slicer, and apply that ratio:

new Rotation Volume = (measured thickness / target thickness) × current Rotation Volume

Full method: Rotation Volume calibration.

Common issue — clogging at the Feeding Zone

If melted plastic flows back up into the hopper:

Lower the Feeding Zone by 10°C
Verify SmoothFlow dosage isn’t too high
Avoid printing too slowly — pellets shouldn’t dwell in heat

Stepper motor losing steps at low speeds

When the extruder motor “tak-tak-taks” at low speeds:

Apply SmoothFlow to the pellets
Optionally raise the Feeding Zone temperature by 5–10°C

See Extruder motor skipping for full diagnosis.

Best practices

Monitor extrusion behavior during the first layers and adjust gradually
Keep a log per material/batch: temperatures, MVS, additive %, supplier — repeatability matters
Use SmoothFlow proactively when working with PETG, rPLA, or reinforced grades
Don’t expect two grades of the same polymer to behave identically