Retraction Test for PrusaSlicer – Stringing Ring, Any Firmware | HexCalibr

A ring of small pillars where every gap gets its own retraction length, in one 16-minute print. Look at the ring one gap at a time: the first clean gap is your retraction length. Works on every firmware, with no profile changes and no firmware retraction.

Step-by-step guide

Photos of strings and clean gaps, and where the value goes in PrusaSlicer: hexcalibr.ui4.eu/retraction.html

One extra step: the rewriter page

PrusaSlicer has one retraction length for the whole print, so a 3MF alone can't change it gap by gap. This file only adds a comment to the G-code. Export the G-code, drop it on the retraction rewriter, and print the file it gives back: every retraction between two neighbouring pillars is set to that gap's length, everything else stays as PrusaSlicer wrote it. It reads .gcode and binary .bgcode, and nothing is uploaded: it runs in your browser.

Why HexCalibr

• Any firmware. Prusa (MK4, Core One, MINI, XL), Klipper, Marlin, RepRapFirmware: the rewritten file uses plain G-code retractions, so there is no firmware retraction to enable and nothing to change in printer.cfg.

• Every length in the same conditions. Side by side on one ring, same height, same layer, same temperature: one photo shows them all.

• Short. 16 minutes and about 4 g, instead of an hour-long tower.

• Your own settings. Wipe, z-hop, retraction speed and the extra length on restart stay as your profile has them; only the length changes.

Quick steps

1. Clean the nozzle. Check that your retraction length is above 0.

2. Download the file for your extruder (not "Download all" as a ZIP) and open it in PrusaSlicer 2.9 with File › Open project, never Import. Slice and Export G-code.

3. Drop the G-code on the rewriter and print the file you download.

4. With something dark inside the ring, look at one gap at a time from outside. Start from 0: the first gap with no strings and no blobs is your length.

5. Type it in Filament Settings › Filament Overrides › Retraction › Length (tick it) and save the filament preset.

A real result

PETG on a RatRig V-Core 4 IDEX (RatOS, T0, direct drive), 16 min. 0.0 mm: strings everywhere and blobs on the pillar sides. 0.2 mm: still strings at every height. From 0.4 mm on the gaps were clean, with 0.8 (the profile's value) no better. Only one fine hair at the top crossed every gap, the same at every length: that one isn't retraction.

Share your Make

Printed it? Post a Make with a photo of the ring and say which gap was the first clean one. Makes help other people read their own rings.

Watch the trailer

License and credits

CC BY-SA 4.0. HexCalibr by Matteo Beretta. If you share or remix it, credit "HexCalibr by Matteo Beretta", link back to this page, and keep the same license. The HexCalibr name and logo are not covered by the license: please give modified versions a different name. The official, always-updated files are on this page. Original design (see License and credits).

Not affiliated with or endorsed by Prusa Research, Rat Rig, the Klipper or Marlin projects, or any other brand named here. All trademarks belong to their owners.

Version 0.1 · made for PrusaSlicer 2.9 (2.7 minimum).

🇮🇹 Italiano

Un anello di piccoli pilastri in cui ogni spazio ha la sua lunghezza di retrazione, in una stampa da 16 minuti: il primo spazio pulito è la tua lunghezza. Funziona con ogni firmware, senza modifiche ai profili. Apri il file con File › Apri progetto, esporta il G-code e passalo nel riscrittore prima di stamparlo. Guida completa in italiano: hexcalibr.ui4.eu/it/retraction.html