Stringing and Oozing
Reduce strings between printed features with dry filament, the stock material profile, and temperature or retraction calibration when needed.
Download the Test File
The test procedure is the same for V2, V3 and V4. No slicing is needed.
- V2 / V3: Download the test-print archive. With the printer idle, install the ZIP without extracting it through Web Interface > Machine-Specific > Install Update. Wait for installation to finish, then find the test under Jobs > Test prints > Material Tuning.
- V4: Use the test under Jobs > Material Tuning. If missing, download Retraction Test.gcode and upload through Web Interface > Jobs.
Stringing leaves fine threads between separate features when the nozzle travels without printing. Start with dry filament and the correct stock profile, then investigate temperature and retraction only as needed.
A small amount of material dripping from an idle hot nozzle is not the same test as strings across a printed part. Use a repeatable print to judge changes.
Prepare a Comparison
Choose a small model with two separated features so travel crosses an open gap. Keep the model, orientation, layer height, and nozzle fixed. Save a copy of the profile and record the starting temperature and retraction settings.
| What you see | Next step |
|---|---|
| Fine threads across travel gaps | Drying and temperature checks below |
| Thick deposits at a seam | Blobs and Zits |
| Strings only after switching heads | The tool-change check below |
| Strings plus inconsistent feeding or clicking | Inspect feeding before tuning retraction |
1. Dry the Material First
Dry the filament using Filament Drying, with the appropriate conditions for that material. A newly opened spool is not proof that the material is dry.
Repeat the comparison print with the stock profile. Keep the material protected from moisture during use as described in the drying guide. If the result improves, confirm it on the original job before changing other settings.
Drying is the first check, but it does not mean retraction can be disabled for every material or print.
2. Establish Temperature
Use the printer-specific material profile as your starting point. If strings remain on dry filament, follow the temperature test in Material Tuning. Its supplied files require a 0.4 mm nozzle; check those requirements first.
Compare surface quality and layer bonding together. A temperature that removes threads but leaves poor layer adhesion is not a successful setting. Save the selected result to the material profile, then re-slice and repeat the comparison print.
3. Review Retraction and Restart Settings
Test file: Download Retraction Test.gcode. In the Web Interface, open Jobs and upload the file. It is a ready-to-print G-code file and does not need slicing. On V4, a copy is included under Jobs > Material Tuning.
For a supported material, compare the slicer profile and any edited printer macros with their stock settings. Check whether retraction is being controlled by the slicer or through firmware macros before making changes.
For ordinary travel retraction, use Printer Settings > Extruder 1 / Extruder 2 > Retraction in PrusaSlicer and check any overrides under Filament Settings > Filament Overrides. Restore the matching Vision Miner profile's values rather than applying the tool-change distances below to travel moves.
Restore unintended changes first. Keep stock travel, wipe, and Z-hop settings as the baseline so several variables do not change at once.
If the material needs its own settings, run repeated short comparison prints:
- Keep temperature and flow fixed after calibration.
- Change one retraction setting by a small amount and record it.
- Inspect both the travel gap and the beginning of the next printed line.
- Reject settings that reduce strings but introduce restart gaps, grinding, or delayed flow.
- Save the best repeatable result in a separate profile.
Flexible or additive-filled materials may need different settings from the standard material profiles. There is no single retraction-distance increase that is appropriate for all of them.
4. Check Tool Changes and Nozzle Deposits
If strings appear only after one head returns from parking, observe whether a thread remains on its nozzle after heating and cleaning. For supported alternating-head jobs, check Prime Tower behavior in the profile and preview; see Blobs and Zits.
On V4, open Web Interface > Macros > System > Settings > Printing > Tool Change Retraction. Choose Tool 0 or Tool 1, then Retraction or Extrusion. To restore firmware defaults, enter 5 mm for Retraction and 10 mm for Extrusion, repeating for each tool. Enter positive distances. These settings control parking and priming at tool changes; they do not set ordinary travel retraction. See Tool Change Retraction for the full procedure. On V2/V3, confirm the available macro and its defaults for your firmware before applying these V4 values.
Inspect for external material buildup when the printer is stopped, using the applicable nozzle maintenance procedure. Plastic leaking around the heater block requires hotend inspection rather than a larger retraction setting.
Verify the Result
Repeat the original model with the saved profile. Check for fewer strings, continuous restart lines, and unchanged layer bonding. Confirm again after several tool changes if the job uses both heads.
Record the Diagnostic Results
Keep comparison photos with material and drying details, nozzle type and diameter, the slicer project, and a record of each setting changed. These notes make it possible to repeat the best result or give support a clear comparison.
For general slicer background, see Prusa's Stringing and Oozing. Use your 22IDEX profile rather than another printer's retraction values.
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