3D Printing: Stringing, Retraction, Drying

Lisa Ernst · 20.11.2025 · Technology · 7 min

We still vividly remember our first prints with endless fine threads between the parts – classic PLA "cobwebs." It looks harmless at first glance, but it immediately makes the part less professional. At the same time, you often don't know whether to adjust the temperature, retraction, or filament. We see exactly these stringing problems in our workshop at 33d.ch almost daily – and yes, it happened to us at the beginning too. In the following sections, we'll show you based on our practical experience how to get these threads under control step by step.

Quelle: Own Presentation

Stringing is one of the most common topics in FDM printing courses and support emails we receive from hobby makers, schools, and SMEs. Anyone who ignores it wastes printing time, has to painstakingly remove strands, and risks errors on functional surfaces. The good news: With a few targeted tests on retraction, temperature, travel, and filament drying, the problem can usually be reduced very effectively in practice – without needing to buy new hardware.

Fundamentals of Stringing

The goal is a clean print without fine threads between individual printed parts. These threads are called "stringing" or "oozing" – the molten filament drips while the print head travels and draws thin threads between already printed areas. In our workshop, we particularly see this with tall, slender parts with some distance between them. (Source)

Use Cases: If your model has, for example, several small, separate towers, or if your print head travels over open areas – that's precisely where stringing is particularly visible.

Important Technical Terms:

• Retract or Retraction = Pulling the filament back into the nozzle to reduce material outflow during travel. (Source)
• Nozzle Temperature = Temperature of the nozzle; too high means filament becomes very liquid → more dripping. (Source)
• Filament Moisture = Filament has absorbed water and steams when heated → uncontrolled filament leakage. (Source)
• Infill = simplified, the inner structure of the part; high infill values extend printing time but usually have less impact on stringing than retraction and temperature.

Preparation for Testing

Before you get lost in the settings, a brief checklist is worthwhile. This way, you can prevent false conclusions like "the slicer is to blame" when in reality, the nozzle is just dirty or the bed is warped.

• Current slicer (e.g., Cura, PrusaSlicer, or similar tool) and a simple stringing test (several small towers with spacing).
• Printer mechanically in order: clean nozzle, correctly adjusted print bed, calibrated extruder (step width, feed rate).
• The planned filament – ideally not completely soaked from the workshop air, but dry and ready for use.
• Filament storage in view: store open spools preferably in a dry container or box with silica gel.

At 33d.ch, we've made it a habit to always run stringing tests with the same reference model. This way, we can see at a glance if anything has truly improved or if we're just convincing ourselves. For these tests, prepare small, clearly defined parameter ranges – for example, steps of 5 °C for temperature or 0.5–1 mm for retraction.

Step-by-Step Guide

In the next step, we'll go through the typical adjustment screws in a sensible order. If you only change one parameter at a time, you'll quickly see which change really helps – everything else makes little sense and only costs filament.

Step 1: Prepare Test Print

Goal: A baseline on which you can track changes. Procedure: Select a model with separate islands or towers (e.g., five cylindrical towers spaced about 10 mm apart). Slice with your default values (e.g., retraction = 2 mm, speed, etc.). Start the print and then evaluate: Are fine threads appearing between the islands? Then move on. Success Check: no cobweb-like threads visible anymore = good starting point.

Quelle: china-gadgets.de

Different stringing grades on test objects used for calibration.

Step 2: Adjust Retraction

Goal: Activate and optimize filament retraction during print head travel. Procedure:

• Check if "Retract" is activated. If not, activate it. (Source)
• Guideline depending on the extruder system: Direct drive starts, for example, at 0.5-2 mm retraction length; Bowden systems rather at 4-7 mm. (Source)
• Retraction speed: Start, for example, at 25–40 mm/s. (Source)

Procedure: Start with your default values, then increase the retraction length in increments of +0.5–1 mm and test again. If filament under-extrusion or clicking in the extruder occurs, reduce slightly. Success Check: significantly fewer or no threads between the towers.

In our workshop, we've found it best to optimize retraction first before activating exotic slicer features. Anyone who fiddles with dozens of special options too early quickly loses track of which setting actually helped.

Quelle: the3dprinterbee.com

Retraction settings in Ultimaker Cura software.

Step 3: Optimize Print Temperature

Goal: Set the temperature so that filament extrudes well but doesn't drip excessively. Procedure:

• Know the recommended temperature range for your filament (e.g., PLA 190-210 °C). (Source)
• Start in the middle range, then lower the temperature in 5 °C steps. (Source)

Example: You print PLA at 205 °C – lower to 200 °C → check for stringing. Still threads? Maybe down to 195 °C. Caution: Check layer adhesion afterward. Success Check: No more threads + stable layers.

Step 4: Utilize Travel Movement and Slicer Features

Goal: Minimize the time the nozzle travels over open space and could drip. Procedure:

• Increase travel speed (e.g., 150-200 mm/s depending on the machine). (Source)
• Activate "Combing" or "Avoid Crossing Perimeters" – so the head travels within printed areas as much as possible and not over open gaps. (Source)
• Optional: Z-Hop (nozzle lifts slightly during travel) – can help, but sometimes intensifies stringing, so test it. (Source)

Success Check: The test model clearly shows whether no or only minimal threads are pulled between the islands.

Step 5: Filament Quality and Dry Storage

Goal: Ensure that the filament is not moist or of poor quality. Procedure:

• If the filament has been exposed to open air or humid environments for a long time, then dry it: e.g., in the oven at 50-60 °C for a few hours. (Source)
• Store filament dry in an airtight container with silica gel. (Source)
• Observation: Audible popping noises during printing = indication of moisture. (Source)

Success Check: After drying and storage, no more stringing problems, with other settings remaining the same.

At 33d.ch, a simple routine has proven effective: Spools that have been left open for too long or extrude visibly "rough" go into the filament dryer first before important orders. This costs a few hours but ultimately saves significantly more time than reworking heavily stringed parts. (Source)

This video shows you exactly one important step in adjusting retraction and provides good visual hints.

Common Problems & Solutions

Quelle: the3dprinterbee.com

Significant stringing on a 3D printed cube model.

We encounter the following error patterns most frequently at 33d.ch when customers come with "cobweb problems." Short version as an overview:

Error 1: Stringing despite retraction activated

Diagnosis: Retraction length or speed too low, nozzle too hot, travel movement too slow. Solution: Increase retraction distance, increase speed, lower temperature. Example: Printer with Bowden system had only 2 mm retraction → at 4 mm, stringing was significantly reduced.

Error 2: Under-extrusion after increasing retraction

Diagnosis: Retraction distance too large or poor filament feeding. Solution: Gradually reduce retraction (e.g., 1 mm less), calibrate extruder. Guide: Direct drive usually <2 mm retraction. (Source)

Error 3: Stringing only with specific material or color

Diagnosis: This filament has moisture or is a bad batch. Solution: Dry or replace filament; use different parameters than for standard PLA. (Source)

Error 4: No improvement despite adjusting settings

Diagnosis: Nozzle is clogged or heavily worn, filament quality is extremely poor. Solution: Clean or replace nozzle; use quality filament. (Source)

Material and Hardware Adjustments

For different materials: PLA is more forgiving, temperature-wise in the 190-210 °C range; PETG is more robust (e.g., 230-250 °C) and more prone to stringing; TPU/Nylon require extra care (more drying, sometimes longer retraction). (Source)

If you have direct drive hardware, you can use shorter retraction values than with Bowden systems. Slicer features like "Coasting," "Wipe," or "Early Retract" can also help depending on the system. (Source)

In our customer projects, we've found that simply switching from a long Bowden setup to a direct drive extruder can significantly reduce the required retraction length. Those who frequently print technical small series save not only on strings but also a lot of time in calibration.

Those printing many small islands or very fine details might consider setting "Minimum Travel Distance" lower in slicer settings so that retraction engages even for short movements. (Source)

Further Resource: More slicer tutorials on stringing avoidance (e.g., combing techniques).

FAQ: Frequently Asked Questions from Practice

Here are answers to frequently asked questions and a summary of the most important findings.

Question: Why do I still have small threads after adjustments?

Answer: Small threads often cannot be entirely avoided. If retraction becomes too long or the temperature too low, under-extrusion may occur. Small residual threads can be removed with a hot air gun or brush, but better values are usually achieved through clean test series of retraction and temperature. (Source)

Question: Will stringing affect my print strength?

Answer: In most cases, stringing primarily affects the surface and appearance. Mechanically, it rarely plays a role, but visually it's unsightly and can make support removal more difficult.

Question: Can travel speed be set too high?

Answer: Yes, if the machine experiences vibrations or inaccuracies due to high speed. Then other errors can occur. Travel speed should suit the printer – many manufacturers cite ~150-200 mm/s as a good range. (Source)

Question: Do I have to readjust retraction every time I use new filament?

Answer: Not necessarily, but with new material, different color, or different manufacturer, we recommend a short test print. Different filaments react differently to retraction and temperature.

Question: Does it make sense to only change the temperature instead of retraction?

Answer: Lowering the temperature is a good measure – but it's often not enough on its own. If the retraction length is significantly too low, the problem persists. Optimizing retraction + temperature + travel movement together yields the best results in practice.

Mini-Conclusion: Keeping Stringing Under Control Permanently

• First, print a simple stringing test model before producing important parts.
• Start with sensible default retraction values and adjust length and speed in small increments.
• Lower the nozzle temperature in 5 °C steps until stringing significantly decreases without affecting layer adhesion.
• Use travel features like high travel speed, combing, and optional Z-hop, instead of letting the head slowly chug over open areas.
• Store filament consistently dry – if everything else is right and the material still "pops" and pulls threads, a dried or new filament is worth more than hours of fine-tuning.

In our workshop, we have a small calibration profile with proven stringing settings for each material. This way, we only need to make fine adjustments on new projects instead of starting from scratch every time.

Quelle: YouTube

This second video shows you the mechanics of retraction in detail and how stringing occurs – ideal for deepening your understanding if you want to visualize the processes in the hotend better.

Perfectly Matches

• Understanding 3D Printing Tolerances
• Storing and Drying Filament Properly
• The Most Important Slicer Settings for Beginners
• Material Comparison PLA, PETG, ABS, and TPU in FDM Printing
• Analyzing 3D Printing Error Patterns Systematically

Good luck with clean printing!