Retraction

Retraction is a slicer setting where the extruder pulls filament back a short distance during travel moves (non-printing movements) to relieve pressure in the nozzle and prevent molten material from oozing or dripping onto the print.

How It Works

When the hot end is at printing temperature, the molten filament inside the nozzle is under constant pressure from the filament behind it. During travel moves — when the nozzle moves from one part of the print to another without extruding — this pressure can force a small amount of material out of the nozzle. That leaked material forms thin, wispy strings across the open space, a defect known as stringing or oozing.

Retraction counteracts this by reversing the extruder drive gear for a fraction of a second, pulling the filament backward and reducing the pressure inside the nozzle chamber. When the nozzle arrives at the next print position, the extruder pushes the retracted filament back in before resuming extrusion. This cycle happens dozens or hundreds of times per print.

Key Parameters

Two values control retraction: distance and speed. The optimal settings depend entirely on your extruder type.

Direct Drive Extruders — the extruder is mounted directly above the hot end. The filament path is very short, so only a small retraction is needed. Typical range: 0.5–1.5 mm at 30–45 mm/s. Excessive retraction with direct drive can pull molten filament into the heat break, causing a clog.

Bowden Extruders — the extruder is mounted on the printer frame, and filament travels through a long PTFE tube to the hot end. The flexible tube introduces slack, so a larger retraction is required. Typical range: 4–6 mm at 25–40 mm/s. Too little retraction causes stringing; too much can wear down the filament or cause jams in the Bowden tube.

Common Issues

Stringing is the number one beginner print defect, and retraction adjustment is the first fix to try. If retraction alone doesn’t eliminate stringing, check two other factors:

1. Nozzle temperature — even 5–10°C too high can make filament too runny. Try lowering the temperature in 5°C increments.
2. Filament moisture — wet filament (especially PETG and nylon) expands and oozes more. Dry the filament or try a fresh spool.

Some slicers offer a “Retract Before Outer Wall” option, which adds a small retraction just before printing the outer perimeter. This reduces pressure and produces cleaner surface finish on external walls. For advanced users, wipe (moving the nozzle along the already-printed wall during travel) and coasting (stopping extrusion slightly before the end of a path to use residual pressure) can further reduce stringing without increasing retraction distance.